JP6891564B2 - Transparent heat-resistant laminated film, transparent flexible printed circuit board, transparent electrode substrate, lighting device and organic electroluminescence display device - Google Patents

Description

The present invention relates to a transparent heat-resistant laminated film, a transparent flexible printed circuit board, a transparent electrode substrate, a lighting device, and an organic electroluminescence display device, and in particular, can improve wet heat durability adhesion to a metal layer while maintaining transparency. It relates to a transparent heat-resistant laminated film that can be formed.

In recent years, flexible substrates have come to be used with the miniaturization and weight reduction of electronic devices and the like. For example, a flexible substrate is also required for lighting applications, and a film having excellent heat resistance such as a polyimide film may be used as a general flexible substrate film for LED lighting devices (see, for example, Patent Document 1). .).
In the transparent heat-resistant laminated film, for example, since there is a problem when it is used for a display or the like, a resin having high transparency and a high coefficient of thermal expansion (CTE) is used.
Further, in the transparent heat-resistant laminated film, a metal layer such as a metal foil is adhered on the base film, but in order to secure the adhesiveness between the base film and the metal layer, a three-layered base film is known. Has been done. For example, a transparent heat-resistant laminated film that can be bonded to a metal layer by laminating by using a non-thermoplastic polyimide resin for the core layer and using a thermoplastic polyimide resin on both surfaces as a base film. (See, for example, Patent Document 2).

However, when the wet and heat durability evaluation was performed on the transparent heat-resistant laminated film as described above, it was found that the metal layer was interfacially peeled from the base film.

International Publication No. 2009/107433 Japanese Unexamined Patent Publication No. 2013-75525

The present invention has been made in view of the above problems and situations, and the problem to be solved is a transparent heat-resistant laminated film capable of improving wet heat durability adhesion to a metal layer while maintaining transparency, the transparent film. It is an object of the present invention to provide a transparent flexible printed circuit board, a transparent electrode substrate, a lighting device, and an organic electroluminescence display device provided with a heat-resistant laminated film.

In order to solve the above problems, the present inventor reduces the coefficient of thermal expansion of the B layer on which the metal layers are laminated and has a higher coefficient of thermal expansion than the B layer in the process of examining the cause of the above problem. We have found that by laminating the highly transparent A layer under the B layer, it is possible to improve the adhesion peeling due to the dimensional change between the B layer and the metal layer in the moist heat durability evaluation while maintaining the transparency, and have reached the present invention.
That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. A transparent heat-resistant laminated film having layers A and B containing a transparent heat-resistant resin and a metal layer in this order.
The A layer contains a fluorinated polyimide resin and contains
The layer B contains a polyimide resin, and the polyimide resin has an imide group concentration in the range of 20 to 30% by mass after imidization of the polyimide precursor.
The B layer has a smaller coefficient of thermal expansion and a thinner layer thickness than the A layer.
The coefficient of thermal expansion of the B layer is in the range of 10 to 40 ppm / ° C.
The yellow index value including the A layer and the B layer is 3.0 or less.
A transparent heat-resistant laminated film in which the A layer and the B layer are bonded by a thermosetting type or photocurable type adhesive.

2. The transparent heat-resistant laminated film according to item 1, wherein the ratio of the thickness of the A layer to the B layer is within the range of A layer: B layer = 99: 1 to 67:33.

3. 3. The A layer contains dichloromethane and is
The transparent heat-resistant laminated film according to item 1 or 2, wherein the content of dichloromethane is in the range of 1 to 800 mass ppm.

4 . A transparent flexible printed circuit board comprising the transparent heat-resistant laminated film according to any one of items 1 to 3.

5 . A transparent electrode substrate comprising the transparent heat-resistant laminated film according to any one of items 1 to 3.

6 . A lighting device comprising the transparent heat-resistant laminated film according to any one of items 1 to 3.

7 . An organic electroluminescence display device comprising the transparent heat-resistant laminated film according to any one of items 1 to 3.

A transparent heat-resistant laminated film capable of improving wet and heat-durable adhesion to a metal layer while maintaining transparency, a transparent flexible printed substrate provided with the transparent heat-resistant laminated film, and a transparent electrode substrate by the above means of the present invention. , Lighting devices and organic electroluminescence display devices can be provided.
Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.
In the transparent heat-resistant laminated film of the present invention, the coefficient of thermal expansion (CTE) of the B layer on which the metal layer is laminated is reduced, and the A layer having a higher CTE than the B layer but having high transparency is laminated under the B layer. Therefore, the difference between the CTE of the B layer and the CTE of the metal layer can be reduced. As a result, when the moist heat durability evaluation is performed, stress is generated between the metal layer and the base film due to the dimensional change of each layer, but the dimensional change amount of the B layer becomes smaller than the dimensional change amount of the A layer. The generated stress can be reduced, and the metal layer can be prevented from peeling off from the base film.

Schematic diagram of the apparatus used for co-flow spreading according to the present invention.

The transparent heat-resistant laminated film of the present invention is a transparent heat-resistant laminated film having layers A and B containing a transparent heat-resistant resin and a metal layer in this order, and the layer A contains a fluorine-based polyimide resin. The B layer contains a polyimide resin, and the polyimide resin has an imide group concentration in the range of 20 to 30% by mass after imidization of the polyimide precursor. The value of the thermal expansion coefficient is smaller than that of the A layer, the layer thickness is thin, the thermal expansion coefficient of the B layer is in the range of 10 to 40 ppm / ° C., and the A layer and the B layer are present. The yellow index value including the above is 3.0 or less, and the A layer and the B layer are bonded by a heat-curable or photocurable adhesive. This feature is a technical feature common to or corresponding to the invention according to each claim.

In an embodiment of the present invention, the ratio of the thickness of the A layer to the B layer is within the range of A layer: B layer = 99: 1 to 67:33 from the viewpoint of durability adhesion and transparency. Is preferable.

When the A layer contains dichloromethane and the content of the dichloromethane is in the range of 1 to 800 mass ppm, the solvent excessively permeates into the B layer adjacent to the A layer to provide adhesiveness and transparency. It is preferable in that it is possible to prevent the decrease in the amount of the material and the adhesion to the B layer is improved.

The layer A contains a fluorine-based polyimide resin, the layer B contains a polyimide resin, and the polyimide resin has an imide group concentration of 20 to 30% by mass after imidizing the polyimide precursor. It is preferable that it is within the range because it is excellent in transparency and heat resistance.

The transparent heat-resistant laminated film of the present invention is suitably used for a transparent flexible printed circuit board, a transparent electrode substrate, a lighting device, and an organic electroluminescence display device.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

[Overview of the transparent heat-resistant laminated film of the present invention]
The transparent heat-resistant laminated film of the present invention is a transparent heat-resistant laminated film having layers A and B containing a transparent heat-resistant resin and a metal layer in this order. In the present application, the film composed of the A layer and the B layer is also referred to as a base film.
The "transparent" of the transparent heat-resistant resin in the present invention means "transparent" when the YI (yellow index) value satisfies the following conditions when the heat-resistant laminated film is formed using the transparent heat-resistant resin. Is defined as.

<Coefficient of thermal expansion>
The value of the coefficient of thermal expansion of the layer B is smaller than that of the layer A, and the coefficient of thermal expansion of the layer B is in the range of 10 to 40 ppm / ° C. More preferably, it is in the range of 10 to 25 ppm / ° C.
Further, the coefficient of thermal expansion of the layer A is preferably larger than 20 ppm / ° C. The upper limit of the coefficient of thermal expansion of the A layer is preferably 60 ppm / ° C.

Here, the "coefficient of thermal expansion (also referred to as the average linear expansion coefficient) (ppm / ° C.)" of the present application means that when the temperature of the sample changes from T _{1 to T 2} , the length in the uniaxial direction is L ₁ to L. _If it changes to 2, it means the value obtained by dividing the changed length (L _2- L ₁ ) by the sample length (L ₀ ) and the temperature difference (T _2- T _{1) at room temperature or 0 ° C.} (See JIS-K-0129: 2005, JIS-K-7197: 1991)
Coefficient of thermal expansion (ppm / ° C) = [{(L _2- L ₁ ) / L ₀ } / (T _2- T ₁ )] × 10 ⁶

As the thermomechanical analyzer to be used, for example, TMA / SS7100 (manufactured by Hitachi High-Tech Science Corporation) can be used.

As a specific measurement method, for example, a test piece of a film having a thickness of 35 μm composed of a single layer of A layer is made to have a constant size (for example, length 20 mm and width 3 mm), and a force of 50 mN is applied to the test piece. While applying tension, the temperature is raised from 23 ° C. to Tg-50 ° C. of the film at a heating rate of 10 ° C./min, then the temperature is lowered to 23 ° C., and the Tg of the film is again increased from 23 ° C. at a heating rate of 10 ° C./min. The coefficient of thermal expansion at 50 to 200 ° C. at the time of the second temperature rise when the temperature is raised to −50 ° C. is calculated by the following formula.
<Formula> Coefficient of thermal expansion (ppm / ° C.) = ((Sample length at 200 ° C.)-(Sample length at 50 ° C.) / (Sample length at 23 ° C.)) / (200 ° C.-50 ° C.) ) × 10 ⁶
The film composed of the B layer single layer can also be measured in the same manner as described above.

As a means for setting the coefficient of thermal expansion of the A layer and the B layer within the above range, it can be achieved by adjusting the type and content of the resin contained in the A layer and the B layer. Specifically, as will be described later, a fluorine-based polyimide resin is used as the resin of the A layer, a polyimide resin is used as the resin of the B layer, and the polyimide resin has an imide group concentration after imidizing the polyimide precursor. Is preferably in the range of 20 to 30% by mass.

<Yellow index value>
The yellow index (YI) value including the A layer and the B layer is 3.0 or less. It is more preferably in the range of 0.3 to 4.0, and particularly preferably in the range of 0.3 to 2.0. The smaller the yellow index value, the less the coloring, which is preferable.
The yellow index value can be adjusted by selecting the composition of the transparent heat-resistant resin contained in the A layer and the B layer. In order to reduce the yellow index value to 3.0 or less, the A layer will be described later. It is preferable that the transparent heat-resistant resin contained in the layer B is a fluorine-based polyimide resin in the layer A and a polyimide resin in the layer B having an imide group concentration in the range of 20 to 30% by mass.

The yellow index value can be obtained according to the YI (yellow index: yellowish index) of the film defined in JIS K 7103.

As a method for measuring the yellow index value, a sample of a base film composed of layers A and B is prepared, and using the spectrophotometer U-3300 of Hitachi High-Technologies Corporation and the attached saturation calculation program, etc., JIS The tristimulus values X, Y, and Z of the light source color defined in Z 8701 are obtained, and the yellow index value is obtained according to the definition of the following equation.
Yellow index value (YI value) = 100 (1.28X-1.06Z) / Y

<Layer thickness>
The layer thickness of the base film composed of the A layer and the B layer according to the present invention is preferably 200 μm or less from the viewpoint of strength and transparency as a base film and a retardation (also referred to as retardation). More preferably, it is in the range of ~ 100 μm. When the layer thickness is 10 μm or more, the film strength of a certain level or more can be guaranteed. When the layer thickness is 100 μm or less, it is flexible as a printed circuit board.
Further, in the base film, the thickness ratio of the A layer and the B layer is preferably 99: 1 to 67:33. That is, it is preferable that the thickness of the A layer is in the range of 9 to 67 μm and the thickness of the B layer is in the range of 1 to 33 μm.

The layer thickness can be measured, for example, with a contact-type film thickness meter. In addition, the thickness can be measured by cutting the cross section of the film using a microtome and observing the cross section with SEM.

Further, the base film according to the present invention is preferably long, specifically, preferably about 100 to 10,000 m in length, and is wound into a roll. The width of the base film according to the present invention is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably in the range of 1.4 to 4 m.

[Construction of transparent heat-resistant laminated film]
<Layer A and Layer B>
The transparent heat-resistant laminated film of the present invention is a transparent heat-resistant laminated film having layers A and B containing a transparent heat-resistant resin and a metal layer in this order.
The A layer and the B layer are characterized by containing a transparent heat-resistant resin.

[1] Transparent Heat Resistant Resin The transparent heat resistant resin is preferably at least one resin selected from polyimide, polyamic acid, polyarylate and polyether, from the viewpoint of heat resistance and transparency. In the present invention, the A layer contains a fluorine-based polyimide resin, the B layer contains a polyimide resin, and the polyimide resin has an imide group concentration of 20 to 30 mass after imidizing the polyimide precursor. It is preferably in the range of% from the viewpoint of excellent transparency and heat resistance.

The imide group concentration is a value calculated by the following formula in the polyimide resin after imidizing the polyimide precursor.
(Molecular weight of imide group part) / (Molecular weight of all polymers) x 100
Specifically, the imide group concentration is calculated by the following method.
The imide group concentration in units is calculated from the molecular weights of aromatic tetracarboxylic dianhydride and aromatic diamine. For example, in the case of a polyimide having a structure represented by the following formula (X), the imide group concentration is
Imid group molecular weight = 70.03 x 2 = 140.06
Since the unit molecular weight is 894.96,
The imide group concentration (%) = (140.06) / (894.96) × 100 = 15.6%.

[1-1] Polyimide or Polyamic Acid The transparent heat-resistant resin according to the present invention is preferably selected from polyimide or polyamic acid, and more preferably polyimide.

The polyimide or polyamic acid used in the present invention is particularly represented by a polyimide having a repeating unit represented by the following general formula (1) (hereinafter referred to as polyimide (A)) or the following general formula (1'). Polyamic acid (hereinafter, referred to as polyamic acid (A')) having a repeating unit to be used is preferable.
In particular, as the resin used for the A layer according to the present invention, a fluorine-based polyimide resin in which at least one of R and Φ has a fluorine atom in the following general formula (1) is preferable.
Further, as described above, the resin used for the B layer according to the present invention is preferably a polyimide resin or a polyamide resin, and the imide group concentration is preferably in the range of 20 to 30% by mass, and the polyimide resin. This may be a fluorine-based polyimide resin or a non-fluorine-based polyimide resin.

In the general formulas (1) and (1'), R is an aromatic hydrocarbon ring or an aromatic heterocycle, or a tetravalent aliphatic hydrocarbon group having 4 to 39 carbon atoms or an alicyclic hydrocarbon group. is there. Φ is a divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a group composed of a combination thereof, and as a bonding group, −O−, At least selected from the group consisting of _{-SO 2-} , -CO-, -CH _2- , -C (CH ₃ ) _2- , -OSi (CH ₃ ) _2- , -C ₂ H _{4 O- and -S-} It may contain one group.

Examples of the aromatic hydrocarbon ring represented by R include a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysen ring, a naphthacene ring, a triphenylene ring, and an o-terphenyl ring. , M-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronen ring, fluorene ring, fluorantrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphene ring, picene ring, pyrene ring, pyrentrene ring, and anthra Anthrene ring and the like can be mentioned.

Examples of the aromatic heterocycle represented by R include a silol ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, and an oxaziazole ring. , Triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (carbazole ring) (Represents any one or more of the carbon atoms constituting the ring replaced with a nitrogen atom), any one or more of the carbon atoms constituting the dibenzosilol ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or dibenzofuran ring. Ring replaced with a nitrogen atom, benzodifuran ring, benzodithiophene ring, aclysine ring, benzoquinoline ring, phenazine ring, phenanthridin ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidin ring, quinindrin ring, triphenodithiazine Ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofranc ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene ring , Thiophene ring, phenoxatiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.

Examples of the tetravalent aliphatic hydrocarbon group having 4 to 39 carbon atoms represented by R include butane-1,1,4,4-triyl group and octane-1,1,8,8-triyl group. Examples include groups such as decane-1,1,10,10-triyl groups.

Examples of the tetravalent alicyclic hydrocarbon group having 4 to 39 carbon atoms represented by R include cyclobutane-1,2,3,4-tetrayl group and cyclopentane-1,2,4,5. -Tetrayl group, cyclohexane-1,2,4,5-tetrayl group, bicyclo [2.2.2] octo-7-en-2,3,5,6-tetrayl group, bicyclo [2.2.2] Octane-2,3,5,6-tetrayl group, 3,3', 4,4'-dicyclohexyltetrayl group, 3,6-dimethylcyclohexane-1,2,4,5-tetrayl group, 3,6- Examples thereof include groups such as diphenylcyclohexane-1,2,4,5-tetrayl groups.

Examples of the divalent aliphatic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-mentioned bonding group represented by Φ include a group represented by the following structural formula.

In the above structural formula, n represents the number of repeating units, preferably 1 to 5, and more preferably 1 to 3. Further, X is an alkanediyl group having 1 to 3 carbon atoms, that is, a methylene group, an ethylene group, a trimethylene group, or a propane-1,2-diyl group, and a methylene group is preferable.

Examples of the divalent alicyclic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-mentioned bonding group represented by Φ include a group represented by the following structural formula.

Examples of the divalent aromatic hydrocarbon group having 2 to 39 carbon atoms having or not having the above-mentioned bonding group represented by Φ include a group represented by the following structural formula.

Examples of the group composed of a combination of an aliphatic hydrocarbon group represented by Φ, an alicyclic hydrocarbon group and an aromatic hydrocarbon group include a group represented by the following structural formula.

The group represented by Φ is preferably a divalent aromatic hydrocarbon group having 2-39 carbon atoms or a combination of the aromatic hydrocarbon group and an aliphatic hydrocarbon group, particularly preferably. , A group represented by the following structural formula is preferable.

As described above, the polyamic acid (A') corresponds to a structure in which a part of the imide bond of the polyimide (A) is dissociated, and the detailed description of the polyamic acid (A') can be considered in correspondence with the polyimide (A). Therefore, the polyimide (A) will be typically described in detail below.

The repeating unit represented by the general formula (1) is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, still more preferably 80 to 100 mol%, and particularly preferably 80 to 100 mol% with respect to all the repeating units. It is 90 to 100 mol%. The number of repeating units of the general formula (1) in one molecule of polyimide (A) is 10 to 2000, preferably 20 to 200, and the glass transition temperature is 230 to 350 ° C. in this range. Is preferable, and the temperature is more preferably 250 to 330 ° C. The glass transition temperature can be measured by a DSC device (differential scanning calorimetry device), for example, using a differential scanning calorimetry device (DSC-6220 type manufactured by Seiko Instruments Co., Ltd.), the temperature rise rate is 20 ° C. The midpoint glass transition temperature (Tmg) measured at / min and determined according to JIS K7121 (1987) can be determined as the glass transition point (Tg).

Polyimide (A) can be obtained by reacting an aromatic, aliphatic or alicyclic tetracarboxylic dian or a derivative thereof with a diamine or a derivative thereof.

Examples of the aliphatic or alicyclic tetracarboxylic dian derivative include aliphatic or alicyclic tetracarboxylic dianesters, aliphatic or alicyclic tetracarboxylic dianhydride and the like. Of the aliphatic or alicyclic tetracarboxylic acid or its derivative, an alicyclic tetracarboxylic dianhydride is preferable.

Examples of the diamine derivative include diisocyanate and diaminodisilane. Of the diamines or derivatives thereof, diamines are preferable.

Examples of the aliphatic tetracarboxylic acid include 1,2,3,4-butanetetracarboxylic acid. Examples of the alicyclic tetracarboxylic acid include 1,2,3,4-cyclobutanetetracarboxylic dian, 1,2,4,5-cyclopentanetetracarboxylic dian, and 1,2,4,5-cyclohexanetetracarboxylic dian. , Bicyclo [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic acid, Bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, etc. Can be mentioned.

Examples of the aliphatic tetracarboxylic acid esters include monoalkyl esters, dialkyl esters, trialkyl esters, and tetraalkyl esters of the above-mentioned aliphatic tetracarboxylic acids. Examples of the alicyclic tetracarboxylic acid ester include monoalkyl ester, dialkyl ester, trialkyl ester and tetraalkyl ester of the alicyclic tetracarboxylic acid. The alkyl group moiety is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, 1,2. , 4,5-Cyclohexanetetracarboxylic dianhydride, Bicyclo [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, Bicyclo [2.2.2] Examples thereof include octane-2,3,5,6-tetracarboxylic dianhydride. Particularly preferred is 1,2,4,5-cyclohexanetetracarboxylic dianhydride. In general, in polyimide containing an aliphatic diamine as a constituent component, polyamic acid and diamine, which are intermediate products, form a strong salt, so that a solvent having a relatively high salt solubility (for example, cresol) can be used to increase the molecular weight. , N, N-dimethylacetamide, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) are preferably used. However, even in the case of polyimide containing an aliphatic diamine as a constituent component, when 1,2,4,5-cyclohexanetetracarboxylic dianhydride is used as a constituent component, the polyamic acid and the salt of the diamine are bound by a relatively weak bond. Therefore, it is easy to increase the molecular weight, and it is easy to obtain a flexible film.

In addition, for example, 4,4'-biphthalic anhydride, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic hydride, 4- (2,2) 5-Dioxotetrahydrofuryl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-3 Cyclohexene-1,2-dicarboxylic hydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic hydride, 3,4'-oxydiphthalic anhydride, 3,4,9,10-perylenetetra Carboic Acid Dianhydride (Pigment Red 224) 1,2,3,4-Tetramethyl-1,2,3,4-Cyclobutane Tetracarboxylic Acid Dianhydride Tricyclo [6.4.0.02,7] Dodecane- 1,8: 2,7-Tetracarboxylic acid dianhydride and the like can be used.

As the aromatic, aliphatic or alicyclic tetracarboxylic acid or a derivative thereof, one type may be used alone, or two or more types may be used in combination. Further, other tetracarboxylic dians or derivatives thereof (particularly dianhydrides) may be used in combination as long as the solvent solubility of the polyimide, the flexibility of the film, the thermocompression bonding property, and the transparency are not impaired.

Examples of such other tetracarboxylic acids or derivatives thereof include pyromellitic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetracarboxylic acid, 2, 2-bis (3,4-dicarboxyphenyl) propane, 2,2-bis (2,3-dicarboxyphenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1 , 3,3,3-hexafluoropropane, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane, bis (3,4-dicarboxyphenyl) Phenyl) sulfone, bis (3,4-dicarboxyphenyl) ether, bis (2,3-dicarboxyphenyl) ether, 3,3', 4,4'-benzophenone tetracarboxylic acid, 2,2', 3, 3'-benzophenone tetracarboxylic acid, 4,4- (p-phenylenedioxy) diphthalic acid, 4,4- (m-phenylenedioxy) diphthalic acid, 1,1-bis (2,3-dicarboxyphenyl) Aromatic tetracarboxylic acids such as ethane, bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane and their derivatives (particularly dianhydride); Examples thereof include aliphatic tetracarboxylic acids having 1 to 3 carbon atoms and derivatives thereof (particularly dianhydride).

In the method for producing a transparent heat-resistant film of the present invention, it is preferable to contain polyimide or polyamic acid having a fluorene skeleton in order to improve the coloring peculiar to conventional polyimide. The polyimide or polyamic acid having the fluorene skeleton is preferably a compound formed from a diamine or a derivative thereof and an acid anhydride or a derivative thereof, and one of the diamine or the acid anhydride has a fluorene skeleton.

The fluorene skeleton referred to in the present invention means the following structure.

A commercially available polyimide film has a problem that it is colored from yellow to brown due to absorption in the visible light region derived from an intermolecular or intramolecular charge transfer interaction. Further, the above-mentioned film has a problem that the process load is high and the moldability is low, for example, heat treatment at a high temperature is required to form the film into a film. Specifically, the polyimide that forms the film has low solubility in a solvent, and it is difficult to form a film by using the polyimide as it is. Therefore, a film-like coating film is formed by casting on a support or the like using a solvent solution of polyamic acid, which is a precursor of the polyimide, and then the coating film is heat-treated at a high temperature of about 400 ° C. to apply the coating film. It is necessary to imidize the polyamic acid in the film to obtain a film made of polyimide. Therefore, there is a problem that coloring is strong.

In the present invention, preferably by using polyimide or polyamic acid having a fluorene skeleton, the problem of coloring can be improved and a transparent heat-resistant laminated film can be obtained.

Among the acid anhydrides, the acid anhydride having a fluorene skeleton includes, for example, 9,9-bis (3,4-dicarboxyphenyl) fluorenic hydride, 9,9-bis [4- (3,4). -Dicarboxyphenoxy) phenyl] fluorenic hydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-phenylphenyl] fluorenic hydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-phenylphenyl] (2,3-dicarboxyphenoxy) -3-phenylphenyl] fluorenic hydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-phenylphenyl] fluorenic hydride, 9,9-Bis [4- (2,3-dicarboxyphenoxy) -2-phenylphenyl] Fluoleic dianhydride, 9,9-Bis [4- (3,4-dicarboxyphenoxy) -3-methyl Phenyl] Fluoleic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-methylphenyl] Fluoleic dianhydride, 9,9-bis [4- (3,4-3,4-) Dicarboxyphenoxy) -2-methylphenyl] fluorenic acid dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -2-methylphenyl] fluorenic acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-ethylphenyl] fluorenic hydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-ethylphenyl] fluorenic acid dihydride Anhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-ethylphenyl] Fluoleic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy)- 2-Ethylphenyl] Fluoleic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3-propylphenyl] Fluoleic dianhydride, 9,9-bis [4- (2) , 3-Dicarboxyphenoxy) -3-propylphenyl] fluorenic hydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-propylphenyl] fluorenic hydride, 9, 9-Bis [4- (2,3-dicarboxyphenoxy) -2-propylphenyl] Fluoleic dianhydride, 9,9-Bis [4- (3,4-dicarboxyphenoxy) -3-butylphenyl] Fluoleic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-butylphenyl] Fluoleic dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -3- (3,4-dicarboxyphenoxy) -3-butylphenyl] Enoxy) -2-butylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -2-butylphenyl] fluorenic dianhydride, 9,9-bis [4 -(3,4-dicarboxyphenoxy) -3-t-butylphenyl] fluorenic dianhydride, 9,9-bis [4- (2,3-dicarboxyphenoxy) -3-t-butylphenyl] fluorene Acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-t-butylphenyl] Fluoleic dianhydride, 9,9-bis [4- (2,3-di) Carboxyphenoxy) -2-t-butylphenyl] fluorenic dianhydride, etc. can be mentioned. Among these aromatic bis (etheric acid anhydride) compounds, 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic acid dianhydride, 9,9-bis [4- (3) , 4-Dicarboxyphenoxy) -3-phenylphenyl] fluorenic acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-phenylphenyl] fluorenic acid dianhydride, 9, 9-Bis [4- (3,4-dicarboxyphenoxy) -3-methylphenyl] fluorenic acid dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) -2-methylphenyl] Examples thereof include fluorenic acid dianhydride.

Among them, 9,9-bis (3,4-dicarboxyphenyl) fluorenic dianhydride or 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic dianhydride should be used. However, it is preferable from the viewpoint of heat resistance and transparency.

The diamine may be an aromatic diamine, an aliphatic diamine, or a mixture thereof. In the present invention, the "aromatic diamine" represents a diamine in which an amino group is directly bonded to an aromatic ring, and an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or the like is part of the structure thereof. It may contain a substituent (for example, a halogen atom, a sulfonyl group, a carbonyl group, an oxygen atom, etc.). The "aliphatic diamine" represents a diamine in which an amino group is directly bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and an aromatic hydrocarbon group or other substituent (a part of the structure thereof) is used. For example, it may contain a halogen atom, a sulfonyl group, a carbonyl group, an oxygen atom, etc.).

Examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, benzidine, o-trizine, m-trizine, and bis (trifluoromethyl) benzidine. Octafluorobenzidine, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3 , 3'-difluoro-4,4'-diaminobiphenyl, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diamino Diphenylmethane, 4,4'-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminobenzophenone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2- Bis (4- (2-methyl-4-aminophenoxy) phenyl) propane, 2,2-bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) propane, 2,2-bis (4-) (4-Aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (2-methyl-4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (2,6-dimethyl) dimethyl) -4-Aminophenoxy) phenyl) hexafluoropropane, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (2-methyl-4-aminophenoxy) biphenyl, 4,4'-bis (2,6-dimethyl-4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (2-methyl) -4-Aminophenoxy) phenyl) sulfone, bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) ether, bis (4- (2) -Methyl-4-aminophenoxy) phenyl) ether, bis (4- (2,6-dimethyl-4-aminophenoxy) phenyl) ether, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (2-Methyl-4-aminophenoxy) benzene, 1,4-bis (2,6-dimethyl-4-aminophenoxy) benzene, 1,3-bis (4-ami) Nophenoxy) benzene, 1,3-bis (2-methyl-4-aminophenoxy) benzene, 1,3-bis (2,6-dimethyl-4-aminophenoxy) benzene, 2,2-bis (4-amino) Phenyl) propane, 2,2-bis (2-methyl-4-aminophenyl) propane, 2,2-bis (3-methyl-4-aminophenyl) propane, 2,2-bis (3-ethyl-4-aminophenyl) propane Aminophenyl) propane, 2,2-bis (3,5-dimethyl-4-aminophenyl) propane, 2,2-bis (2,6-dimethyl-4-aminophenyl) propane, 2,2-bis (4) -Aminophenyl) Hexafluoropropane, 2,2-bis (2-methyl-4-aminophenyl) hexafluoropropane, 2,2-bis (2,6-dimethyl-4-aminophenyl) hexafluoropropane, α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (2-methyl-4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (2) , 6-Dimethyl-4-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,4-diisopropylbenzene, α, α'-bis (4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (2-methyl-4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (2,6-dimethyl-4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (3-aminophenyl) -1,3-diisopropylbenzene, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (2-methyl) -4-aminophenyl) fluorene, 9,9-bis (2,6-dimethyl-4-aminophenyl) fluorene, 1,1-bis (4-aminophenyl) cyclopentane, 1,1-bis (2-methyl) -4-Aminophenyl) cyclopentane, 1,1-bis (2,6-dimethyl-4-aminophenyl) cyclopentane, 1,1-bis (4-aminophenyl) cyclohexane, 1,1-bis (2-) Methyl-4-aminophenyl) cyclohexane, 1,1-bis (2,6-dimethyl-4-aminophenyl) cyclohexane, 1,1-bis (4-aminophenyl) 4-methyl-cyclohexane, 1,1-bis (4-Aminophenyl) Norbornan, 1,1-bis (2-Methyl-4-aminophenyl) Norborna , 1,1-bis (2,6-dimethyl-4-aminophenyl) norbornane, 1,1-bis (4-aminophenyl) adamantan, 1,1-bis (2-methyl-4-aminophenyl) adamantan , 1,1-bis (2,6-dimethyl-4-aminophenyl) adamantan, 1,4-phenylenediamine, 3,3'-diaminobenzophenone, 2,2-bis (3-aminophenyl) hexafluoropropane, 3-Aminobenzylamine, 9,9-bis (4-amino-3-fluorophenyl) fluorene, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 1,3-bis (3-bis) Aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] sulfone, 1,3-bis [2- (4-aminophenyl) phenyl] ) -2-propyl] benzene, bis (2-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 4,4'-diamino-3 , 3'-dimethyldiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-ethylenedianiline, 4,4'-methylenebis (cyclohexylamine), 4,4'-methylenebis (2,6-diethylaniline), Examples thereof include 4,4'-methylenebis (2-methylcyclohexylamine).

Examples of the aliphatic diamine include ethylenediamine, hexamethylenediamine, polyethylene glycol bis (3-aminopropyl) ether, polypropylene glycol bis (3-aminopropyl) ether, 1,3-bis (aminomethyl) cyclohexane, and 1,4. -Bis (aminomethyl) cyclohexane, m-xylylene diamine, p-xylylene diamine, 1,4-bis (2-amino-isopropyl) benzene, 1,3-bis (2-amino-isopropyl) benzene, isophorone Diamine, Norbornan Diamine, siloxane Diamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, 3 , 3', 5,5'-Tetramethyl-4,4'-diaminodicyclohexylmethane, 2,3-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,5-bis (aminomethyl) -Bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,2-bis (4,4'-diaminocyclohexyl) propane, 2,2 -Bis (4,4'-diaminomethylcyclohexyl) propane and the like can be mentioned.

Examples of the diisocyanate as a diamine derivative include diisocyanates obtained by reacting the above aromatic or aliphatic diamines with phosgene.

Examples of diaminodisilanes that are diamine derivatives include trimethylsilylated aromatic or aliphatic diamines obtained by reacting the above aromatic or aliphatic diamines with chlorotrimethylsilane.

The above diamines and their derivatives may be arbitrarily mixed and used, but the amount of diamine in them is preferably 50 to 100 mol%, more preferably 80 to 100 mol%.

Among the diamines or derivatives thereof, the diamine having a fluorene skeleton or a derivative thereof is preferably an aromatic diamine, for example, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9. -Bis [4- (4-aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- ( 2-Aminophenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4- (4- (4- (4-) 4-) Amino-2-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-ethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- ( 4-Amino-2-ethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-i-propylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-Amino-2-i-propylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-t-butylphenoxy) -3-phenylphenyl] fluorene , 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-3-trifluoromethylphenoxy)- 3-Phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-2-) Methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-4-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-) 5-Methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-6-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3- (3-) 3-phenylphenyl] Amino-2-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-4-trifluoromethylphenoxy) -3-phenylphenyl] fluorene,
9,9-bis [4- (3-amino-5-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (3-amino-6-trifluoromethylphenoxy) -3 -Phenylphenyl] fluorene, 9,9-bis [4- (2-amino-3-methylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-4-methylphenoxy) -3-Phenylphenyl] Fluorene, 9,9-bis [4- (2-amino-5-methylphenoxy) -3-phenylphenyl] Fluorene, 9,9-bis [4- (2-amino-6-methyl) Phenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-3-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino) -4-Trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (2-amino-5-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [ 4- (2-Amino-6-trifluoromethylphenoxy) -3-phenylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) phenyl] fluorene, 9,9-bis [ 4- (4-Amino-2-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) phenyl] fluorene,
9,9-bis [4- (4-amino-2-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) phenyl] fluorene, 9, 9-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-3-methylphenoxy) phenyl] fluorene, 9,9-bis [ 4- (4-Amino-3-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-3-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (4) −Amino-3-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-3-t-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino) -3-Trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-3-methylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-methyl) phenyl] Phenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5-methylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-methylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-3-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-ethylphenoxy) phenyl] fluorene, 9,9-bis [ 4- (2-Amino-5-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-ethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino) -3-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5) -N-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-n-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-3-i) -Propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-i-propylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5-i-propyl) Phenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-i-propylphenoxy) phenyl] fluorene, 9 , 9-Bis [4- (2-amino-3-t-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-4-t-butylphenoxy) phenyl] fluorene, 9,9 -Bis [4- (2-amino-5-t-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-6-t-butylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-Amino-3-trifluoromethylphenoxy) phenyl] Fluorene,
9,9-bis [4- (2-amino-4-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (2-amino-5-trifluoromethylphenoxy) phenyl] fluorene, 9, 9-Bis [4- (2-amino-6-trifluoromethylphenoxy) phenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-methylphenyl] fluorene, 9, 9-bis [4- (4-amino-2-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-methylphenyl] Fluoren, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-methylphenyl] Fluoren, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3-Methylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (4-amino-2) -Methylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino) -2-n-propylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [ 4- (4-Amino-2-t-butylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-ethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-n -Propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2) -I-propylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3-n-propylphenyl] fluorene, 9,9- Bis [4- (4-amino-2-trifluoromethylphenoxy) -3-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-) 2-Methylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-n-propylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-i-propylphenyl ] Fluolene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3-i-propylphenyl] Fluolene, 9,9-bis [4- (4-amino-2-trifluoro) Methylphenoxy) -3-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3-t-butylphenyl] fluorene, 9,9-bis [4- (4-(4-amino-2-methylphenoxy) -3-t-butylphenyl] 4-Amino-2-ethylphenoxy) -3-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3-t-butylphenyl] fluorene, 9 , 9-bis [4- (4-amino-2-i-propylphenoxy) -3-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy)- 3-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3-t-butylphenyl] fluorene, 9,9-bis [4- (4- (4- (4- (4- (4-) 4-) Amino-2-methylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-Amino-2-n-propylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3-trifluoro Methylphenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-) Trifluoromethylphenoxy) -3-trifluoromethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-ethylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-pro) Pyrphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-t-butylphenoxy) -3,5-dimethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3,5-dimethylphenyl ] Fluolene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-diethylphenyl] Fluoren, 9,9-bis [4- (4-amino-2-ethylphenoxy)- 3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-n-propylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (4- (4- (4- (4- (4-) 4-) Amino-2-i-propylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3,5-diethylphenyl] fluorene, 9 , 9-bis [4- (4-amino-2-trifluoromethylphenoxy) -3,5-diethylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3, 5-Di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-n-propylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3, 5-Di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-Amino-2-trifluoromethylphenoxy) -3,5-di-n-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3, 5-di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4 -(4-Amino-2-n-propylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3, 5-di-i-propylphenyl] Fluolene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3,5-di-i-propylphenyl] Fluolene, 9,9-bis [4- (4-amino-2) -Trifluoromethylphenoxy) -3,5-di-i-propylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-di-t-butylphenyl] Fluolene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di-t-butylphenyl] Fluoren, 9,9-bis [4- (4-amino-2-n) -Propylphenoxy) -3,5-di-t-butylphenyl] Fluolene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5-di-t-butylphenyl] Fluolene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3,5-di-t-butylphenyl] Fluoren, 9,9-bis [4- (4-amino-2) -Trifluoromethylphenoxy) -3,5-di-t-butylphenyl] fluorene, 9,9-bis [4- (4-amino-2-methylphenoxy) -3,5-di (trifluoromethyl) phenyl ] Fluolene, 9,9-bis [4- (4-amino-2-ethylphenoxy) -3,5-di (trifluoromethyl) phenyl] Fluoren, 9,9-bis [4- (4-amino-2) -N-propylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene, 9,9-bis [4- (4-amino-2-i-propylphenoxy) -3,5-di (trifluoro) Methyl) phenyl] fluorene, 9,9-bis [4- (4-amino-2-t-butylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene, 9,9-bis [4- (4- (4-) 4-Amino-2-trifluoromethylphenoxy) -3,5-di (trifluoromethyl) phenyl] fluorene,
9,9-Bis [4- (2-amino-3-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-4-methylphenoxy) -3-methylphenyl] Fluolene, 9,9-bis [4- (2-amino-5-methylphenoxy) -3-methylphenyl] Fluoren, 9,9-bis [4- (2-amino-6-methylphenoxy) -3-methyl Phenyl] fluorene, 9,9-bis [4- (2-amino-3-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-4-trifluoromethyl) 4- (2-amino-4-trifluoromethyl) Phenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino-5-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-amino) -6-Trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-Amino-4-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [ 4- (3-Amino-6-methylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-ethylphenoxy) -3-methylphenyl] fluorene, 9,9- Bis [4- (3-amino-4-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-ethylphenoxy) -3-methylphenyl] fluorene, 9, 9-bis [4- (3-amino-6-ethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-n-propylphenoxy) -3-methylphenyl] Fluoren, 9,9-bis [4- (3-amino-4-n-propylphenoxy) -3-methylphenyl] Fluoren, 9,9-bis [4- (3-amino-5-n-propylphenoxy)] -3-Methylphenyl] fluorene, 9,9-bis [4- (3-amino-6-n-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2) -I-propylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-4-i-propylphenoxy) -3-methylphenyl Enyl] Fluorene, 9,9-bis [4- (3-amino-5-i-propylphenoxy) -3-methylphenyl] Fluoren, 9,9-bis [4- (3-amino-6-i-propyl) Phenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-t-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino) -4-t-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-t-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [ 4- (3-Amino-6-t-butylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-2-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-4-trifluoromethylphenoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (3-amino-5-trifluoromethylphenoxy) -3 -Methylphenyl] fluorene, 9,9-bis [4- (3-amino-6-trifluoromethylphenoxy) -3-methylphenyl] fluorene and the like can be mentioned.

The polyimide or polyamic acid having a fluorene skeleton is a diamine or a derivative thereof, and as an acid anhydride or a derivative thereof, the diamine is 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-). It is preferably either amino-3-methylphenyl) fluorene or 9,9-bis (3-fluoro-4-aminophenyl) fluorene, and the acid anhydride is 9,9-bis (3,4-). It is preferable to use either dicarboxyphenyl) fluorene dianhydride or 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorenic acid dianhydride from the viewpoint of improving non-colorability. ..

The polyamic acid can be obtained by polymerizing at least one of the tetracarboxylic acids and at least one of the diamines in a suitable solvent.

The polyamic acid ester is formed by diesterifying the tetracarboxylic acid dianhydride with an alcohol such as methanol, ethanol, isopropanol, or n-propanol, and the obtained diester is used in an appropriate solvent. It can be obtained by reacting with a diamine compound. Further, the polyamic acid ester can also be obtained by esterifying the carboxylic acid group of the polyamic acid obtained as described above by reacting with the alcohol as described above.

The reaction between the tetracarboxylic dianhydride and the diamine compound can be carried out under conventionally known conditions. The order and method of adding the tetracarboxylic dianhydride and the diamine compound are not particularly limited. For example, a polyamic acid can be obtained by sequentially adding a tetracarboxylic dianhydride and a diamine compound to a solvent and stirring the mixture at an appropriate temperature.

The amount of the diamine compound is usually 0.8 mol or more, preferably 1 mol or more, based on 1 mol of the tetracarboxylic dianhydride. On the other hand, it is usually 1.2 mol or less, preferably 1.1 mol or less. By setting the amount of the diamine compound in such a range, the yield of the obtained polyamic acid can be improved.

The concentrations of the tetracarboxylic dianhydride and the diamine compound in the solvent are appropriately set according to the reaction conditions and the viscosity of the polyamic acid solution. For example, the total mass of the tetracarboxylic dianhydride and the diamine compound is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more, based on the total amount of the solution, while usually 70. It is mass% or less, preferably 30 mass% or less. By setting the amount of the reaction substrate in such a range, polyamic acid can be obtained at low cost and in good yield.

The reaction temperature is not particularly limited, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, while it is usually 100 ° C. or lower, preferably 80 ° C. or lower. The reaction time is not particularly limited, but is usually 1 hour or more, preferably 2 hours or more, while it is usually 100 hours or less, preferably 24 hours or less. By carrying out the reaction under such conditions, a polyamic acid can be obtained at low cost and in good yield.

Examples of the polymerization solvent used in this reaction include hydrocarbon solvents such as hexane, cyclohexane, heptane, benzene, toluene, xylene and mesitylen; carbon tetrachloride, methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene and di. Halogened hydrocarbon solvents such as chlorobenzene and fluorobenzene; ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane and methoxybenzene; ketone solvents such as acetone and methyl ethyl ketone; N, N-dimethylformamide, N, N Amido solvents such as -dimethylacetamide and N-methyl-2-pyrrolidone; aproton polar solvents such as dimethylsulfoxide and γ-butyrolactone; heterocyclic solvents such as pyridine, picolin, lutidine, quinoline and isoquinolin; phenol and cresol Examples thereof include, but are not limited to, phenolic solvents such as. As the polymerization solvent, only one kind may be used, or two or more kinds of solvents may be mixed and used.

Further, the polymerization reaction may be controlled by adding a small amount of end-capping agent to the aromatic diamines before the polymerization reaction.

As will be described later, the polyimide can be obtained by heat-treating a film in which a polyamic acid solution is cast, or by casting a polyamic acid solution mixed with a ring-closing catalyst onto a support to imidize the film. Specific examples of the ring-closing catalyst include aliphatic tertiary amines such as trimethylamine and triethylenediamine and heterocyclic tertiary amines such as isoquinoline, pyridine and picoline, which are selected from heterocyclic tertiary amines. It is preferable to use at least one amine. The content of the ring-closing catalyst with respect to the polyamic acid is preferably in the range in which the content of the ring-closing catalyst (mol) / the content of the polyamic acid (mol) is 0.5 to 8.0.

As the polyamic acid or polyimide constructed as described above, those having a weight average molecular weight of 30,000 to 1,000,000 are used from the viewpoint of forming a film.

Further, the polyamic acid may be imidized at the time of casting, and the imidization ratio at the time of casting is preferably 10 to 100%. Here, the imidization ratio can be obtained from the peak obtained by Fourier transform infrared spectroscopy by the following formula.

Formula (A): (C / D) × 100 / (E / F)
In the above formula (A), C ^{represents the absorption peak height of 1370 cm -1} of the polyamic acid or polyimide dope, D represents the absorption peak height ^{of 1500 cm -1 of the polyamic acid or polyimide dope, and E} Represents the absorption peak height of 1370 cm ^-1 of the polyimide film, and F represents the absorption peak height ^{of 1500 cm -1 of the polyimide film.}

By setting the imidization rate of the polyamic acid at the time of casting to 10 to 100%, a polyimide film having a lower elastic modulus than the method of forming a casting film using a polyamic acid having an imidization rate of 0% and then imidizing the film. Can be obtained.

[1-2] Polyarylate The transparent heat-resistant resin according to the present invention may be selected from polyarylate.

<Polyarylate>
Polyarylate contains at least an aromatic dialcohol component unit and an aromatic dicarboxylic acid component unit.

(Aromatic dialcohol component unit)
The aromatic dialcohol for obtaining the aromatic dialcohol component unit is preferably bisphenols represented by the following general formula (2), and more preferably bisphenols represented by the following general formula (2').

L in the general formulas (2) and (2') is a divalent organic group. The divalent organic group is preferably a single bond, an alkylene group, -S-, -SO-, -SO _2- , -O-, -CO- or -CR _{1 R 2-} (R ₁ and R ₂ are each other. Combine to form an aliphatic or aromatic ring).

The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, and an isopropylidene group. The alkylene group may further have a substituent such as a halogen atom or an aryl group.

R ₁ and R ₂ of −CR ₁ R ₂ − are bonded to each other to form an aliphatic ring or an aromatic ring, respectively. The aliphatic ring is preferably an aliphatic hydrocarbon ring having 5 to 20 carbon atoms, and preferably a cyclohexane ring which may have a substituent. The aromatic ring is an aromatic hydrocarbon ring having 6 to 20 carbon atoms, and is preferably a fluorene ring which may have a substituent. _{Examples of −CR 1} R ₂₋ forming a cyclohexane ring which may have a substituent include cyclohexane-1,1-diyl group, 3,3,5-trimethylcyclohexane-1,1-diyl group and the like. included. _{Examples of −CR 1} R ₂₋ forming a fluorene ring which may have a substituent include a fluoreneyl group represented by the following general formula.

R of the general formulas (2) and (2') is independently an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. n is an independently integer of 0 to 4, preferably an integer of 0 to 3.

Examples of bisphenols in which L is an alkylene group include 1,1-bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 1,1-bis (4-methyl-2). -Hydroxyphenyl) methane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-) Hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA), etc. Is included. Among them, 2,2-bis (4-hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2-bis (3,5-dimethyl-). Isopropyridene-containing bisphenols such as 4-hydroxyphenyl) propane (TMBPA) are preferred.

Examples of bisphenols with L of -S-, -SO- or -SO _2- are bis (4-hydroxyphenyl) sulfone, bis (2-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4). -Hydroxyphenyl) sulfone (TMBPS), bis (3,5-diethyl-4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) sulfone, Bis (4-hydroxyphenyl) sulfide, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, bis (3,5-diethyl-4-hydroxyphenyl) sulfide, bis (3-methyl-4-hydroxyphenyl) Includes sulfide, bis (3-ethyl-4-hydroxyphenyl) sulfide, 2,4-dihydroxydiphenyl sulfone and the like. Examples of bisphenols with L -O- include 4,4'-dihydroxydiphenyl ethers; examples of bisphenols with L-CO- include 4,4'-dihydroxydiphenyl ketones. ..

An example of bisphenols in which L is −CR ₁ R ₂₋ and R ₁ and R ₂ bind to each other to form an aliphatic ring is 1,1-bis (4-hydroxyphenyl) cyclohexane (BPZ). , And bisphenols having a cyclohexane skeleton such as 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (BPTMC).

Examples of bisphenols in which L is −CR ₁ R ₂ − and R ₁ and R ₂ are bonded to each other to form an aromatic ring are 9,9-bis (3-methyl-4-hydroxyphenyl). Includes bisphenols having a fluorene skeleton such as fluorene (BCF), 9,9-bis (3,5-dimethyl-4-hydroxyphenyl) fluorene (BXF).

The aromatic dialcohol component constituting the polyarylate may be one kind or two or more kinds.

Among these, from the viewpoint of improving the solubility of the resin in the solvent and improving the adhesion of the transparent heat-resistant laminated film to the metal when applied to a flexible printed substrate, for example, a sulfur atom (-S) in the main chain. -, - SO- or -SO ₂ -) bisphenols containing preferably. From the viewpoint of increasing the heat resistance of the film, for example, bisphenols containing a sulfur atom in the main chain and bisphenols having a cycloalkylene skeleton are preferable. From the viewpoint of reducing the birefringence of the film and increasing the wear resistance, bisphenols having a fluorene skeleton are preferable.

Bisphenols having a cyclohexane skeleton and bisphenols having a fluorene skeleton are preferably used in combination with bisphenols containing an isopropylidene group. In that case, the content ratio of the bisphenol having a cyclohexane skeleton or the bisphenol having a fluorene skeleton to the bisphenol containing an isopropylidene group is 10/90 to 90/10 (molar ratio), preferably 20/80 to 20/80. It is 80/20 (molar ratio).

The polyarylate may further contain an aromatic multihydric alcohol component unit other than the aromatic dialcohol component as long as the effect of the present invention is not impaired. Examples of aromatic polyhydric alcohol components include the compounds described in paragraph [0015] of Japanese Patent No. 4551503. Specifically, tris (4-hydroxyphenyl) methane, 4,4'-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, 2,3. Includes 4,4'-tetrahydroxybenzophenone, 4- [bis (4-hydroxyphenyl) methyl] -2-methoxyphenol, tris (3-methyl-4-hydroxyphenyl) methane and the like. The content ratio of these aromatic polyhydric alcohol component units can be appropriately set according to the required characteristics, and is, for example, 5 with respect to the total of the aromatic dialcohol component units and the other aromatic polyhydric alcohol component units. It can be less than or equal to mol%.

<Aromatic dicarboxylic acid component unit>
The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid component unit is preferably terephthalic acid, isophthalic acid or a mixture thereof.

A mixture of terephthalic acid and isophthalic acid is preferable from the viewpoint of enhancing the mechanical properties of the film. The content ratio of terephthalic acid to isophthalic acid is preferably in the range of terephthalic acid / isophthalic acid = 90/10 to 10/90 (molar ratio), more preferably in the range of 70/30 to 30/70, and further preferably in the range of 50/30. It is in the range of 50. When the content ratio of terephthalic acid is in the above range, a polyarylate having a sufficient degree of polymerization can be easily obtained, and a film having sufficient mechanical properties can be easily obtained.

The polyarylate may further contain aromatic dicarboxylic acid component units other than terephthalic acid and isophthalic acid as long as the effects of the present invention are not impaired. Examples of such aromatic dicarboxylic acid components are orthophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenic acid, 4,4'-dicarboxydiphenyl ether, bis (p-carboxyphenyl) alkane, 4,4'-. Dicarboxyphenyl sulfone and the like are included. The content ratio of the aromatic dicarboxylic acid component unit other than terephthalic acid and isophthalic acid is appropriately set according to the required characteristics, but is the total of the terephthalic acid component, the isophthalic acid component unit and the other aromatic dicarboxylic acid component units. For example, it can be 5 mol% or less.

<Glass-transition temperature>
The glass transition temperature of the polyarylate is preferably in the range of 260 to 350 ° C, more preferably in the range of 265 to 300 ° C, and even more preferably in the range of 270 to 300 ° C.

The glass transition temperature of polyarylate is similarly measured according to JIS K7121 (1987). Specifically, using a DSC6220 manufactured by Seiko Instruments Inc. as a measuring device, measurement can be performed under the conditions of a polyarylate sample of 10 mg and a heating rate of 20 ° C./min.

The glass transition temperature of polyarylate is adjusted by the type of aromatic dialcohol component constituting the polyarylate. In order to raise the glass transition temperature, for example, it is preferable to include "a unit derived from bisphenols containing a sulfur atom in the main chain" as an aromatic dialcohol component unit.

<Intrinsic viscosity>
The intrinsic viscosity of the polyarylate, at 25 ° C., is preferably 0.3~1.0cm ³ / g, more preferably 0.4~0.9cm ³ / g, 0.45~0.8cm ³ / g is even more preferable, and 0.5 to 0.7 cm ³ / g is even more preferable. When the intrinsic viscosity of polyarylate is 0.3 cm ³ / g or more, the molecular weight of the resin composition tends to be constant or higher, and a film having sufficient mechanical properties and heat resistance can be easily obtained. When the intrinsic viscosity of polyarylate is 1.0 cm ³ / g or less, it is possible to suppress an excessive increase in the viscosity of the solution during film formation.

Intrinsic viscosity can be measured according to ISO 1628-1. Specifically, a solution is prepared in which a polyarylate sample is dissolved in 1,1,2,2-tetrachloroethane so as to have a concentration of 1 g / cm ^3. The intrinsic viscosity of this solution at 25 ° C. is measured using an Ubbelohde viscous tube.

The method for producing polyarylate may be a known method, preferably an interface in which an aromatic dicarboxylic acid halide dissolved in an organic solvent incompatible with water and an aromatic dialcohol dissolved in an alkaline aqueous solution are mixed. It is a polymerization method (WM ARECKSON, J. Poly. Sci. XL399, 1959, Japanese Patent Publication No. 40-1959).

The content of the polyarylate is 50% by mass or more, preferably 60% by mass or more, and more preferably 80% by mass or more with respect to the entire polyarylate film.

[1-3] Polyester The transparent heat-resistant resin according to the present invention may be selected from polyether.

The polyether according to the present invention is a structural unit represented by the following general formula (3) (hereinafter, also referred to as “structural unit (3)”) and a structural unit represented by the following general formula (4) (hereinafter, “structure”). It is preferable to have at least one structural unit (i) selected from the group consisting of the unit (4). Therefore, the polyether (I) having the structural unit (i), which will be described later, is excellent in color resistance, heat resistance and light transmission. Further, since the polyether (II) having the structural unit (i) and having a specific molecular weight, which will be described later, has a small amount of low molecular weight components, it is further excellent in color resistance, heat resistance and light transmission.

In the general formula (3), R ^{1 to} R ⁴ independently represent monovalent organic groups having 1 to 12 carbon atoms. Each of a to d independently represents an integer of 0 to 4, preferably 0 or 1, and more preferably 0.

The monovalent organic group having 1 to 12 carbon atoms includes a monovalent hydrocarbon group having 1 to 12 carbon atoms and at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom. Twelve monovalent organic groups and the like can be mentioned.

The monovalent hydrocarbon groups having 1 to 12 carbon atoms include linear or branched hydrocarbon groups having 1 to 12 carbon atoms, alicyclic hydrocarbon groups having 3 to 12 carbon atoms, and 6 to 12 carbon atoms. Examples include aromatic hydrocarbon groups.

As the linear or branched hydrocarbon group having 1 to 12 carbon atoms, a linear or branched hydrocarbon group having 1 to 8 carbon atoms is preferable, and a linear or branched hydrocarbon group having 1 to 5 carbon atoms is used. Hydrogen groups are more preferred.

Preferable specific examples of the linear or branched hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group and n-pentyl. Examples include groups, n-hexyl groups and n-heptyl groups.

As the alicyclic hydrocarbon group having 3 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms is preferable, and an alicyclic hydrocarbon group having 3 or 4 carbon atoms is more preferable.

Preferable specific examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; cyclobutenyl group, cyclopentenyl group and cyclohexenyl group and the like. Cycloalkenyl groups can be mentioned. The binding site of the alicyclic hydrocarbon group may be any carbon on the alicyclic.

Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms include a phenyl group, a biphenyl group and a naphthyl group. The binding site of the aromatic hydrocarbon group may be any carbon on the aromatic ring.

Examples of the organic group having 1 to 12 carbon atoms including an oxygen atom include an organic group composed of a hydrogen atom, a carbon atom and an oxygen atom, and among them, a total carbon composed of an ether bond, a carbonyl group or an ester bond and a hydrocarbon group. The organic groups of numbers 1 to 12 can be preferably mentioned.

Examples of the organic group having a total carbon number of 1 to 12 having an ether bond include an alkoxy group having 1 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, an alkynyloxy group having 2 to 12 carbon atoms, and 6 to 12 carbon atoms. Examples thereof include an aryloxy group and an alkoxyalkyl group having 2 to 12 carbon atoms. Specific examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropyloxy group, a butoxy group, a phenoxy group, a propenyloxy group, a cyclohexyloxy group and a methoxymethyl group.

Examples of the organic group having a carbonyl group and having a total carbon number of 1 to 12 include an acyl group having 2 to 12 carbon atoms. Specific examples thereof include an acetyl group, a propionyl group, an isopropionyl group and a benzoyl group.

Examples of the organic group having a total carbon number of 1 to 12 having an ester bond include an acyloxy group having a total carbon number of 2 to 12. Specific examples thereof include an acetyloxy group, a propionyloxy group, an isopropionyloxy group and a benzoyloxy group.

Examples of the organic group having 1 to 12 carbon atoms including a nitrogen atom include an organic group consisting of a hydrogen atom, a carbon atom and a nitrogen atom, and specifically, a cyano group, an imidazole group, a triazole group, a benzimidazole group and a benz. Examples thereof include a triazole group.

Examples of the organic group having 1 to 12 carbon atoms including an oxygen atom and a nitrogen atom include an organic group composed of a hydrogen atom, a carbon atom, an oxygen atom and a nitrogen atom, and specifically, an oxadiazole group and an oxadiazole group. Examples thereof include a benzoxazole group and a benzoxadiazole group.

^{As R 1 to} R ⁴ in the general formula (3), a monovalent hydrocarbon group having 1 to 12 carbon atoms is preferable, an aromatic hydrocarbon group having 6 to 12 carbon atoms is more preferable, and a phenyl group is further preferable. ..

In the general formula (4), R ^{1 to} R ^{4 and a to d are independently synonymous with R 1 to} R ⁴ and a to d in the general formula (3), respectively, and Y is a single bond. -SO ₂ -or> C = O, R ⁷ and R ⁸ independently represent a halogen atom, a monovalent organic group or a nitro group having 1 to 12 carbon atoms, and m represents 0 or 1. .. However, when m is 0, R ⁷ is not a cyano group. g and h each independently represent an integer of 0 to 4, preferably 0.

Examples of the monovalent organic group having 1 to 12 carbon atoms include an organic group similar to the monovalent organic group having 1 to 12 carbon atoms in the general formula (3).

The polyether has optical properties in terms of the molar ratio of the structural unit (3) and the structural unit (4) (however, both (the total of the structural unit (3) + the structural unit (4) is 100)). From the viewpoint of heat resistance and mechanical properties, the structural unit (3): structural unit (4) is preferably in the range of 50:50 to 100: 0, and the structural unit (3): structural unit (4) = 70. It is more preferably in the range of: 30 to 100: 0, and further preferably in the range of structural unit (3): structural unit (4) = 80:20 to 100: 0.

Here, the mechanical properties refer to properties such as tensile strength, elongation at break, and tensile elastic modulus of the polyether.

Further, the polyether may further have at least one structural unit selected from the group consisting of the structural unit represented by the following general formula (5) and the structural unit represented by the following general formula (6). Good. It is preferable that the polyether has such a structural unit because the mechanical properties of the film containing the polyether are improved.

In the general formula (5), ^{R 5} and ^{R 6} are each independently a monovalent organic group having 1 to 12 carbon atoms, Z is a single bond, -O -, - S -, - SO 2 - ,> C = O, -CONH-, -COO- or a divalent organic group having 1 to 12 carbon atoms, where n represents 0 or 1. e and f each independently represent an integer of 0 to 4, preferably 0.

Examples of the monovalent organic group having 1 to 12 carbon atoms include an organic group similar to the monovalent organic group having 1 to 12 carbon atoms in the general formula (3).

The 012-valent organic group having 1 to 12 carbon atoms is a group consisting of a divalent hydrocarbon group having 1 to 12 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 12 carbon atoms, an oxygen atom and a nitrogen atom. A divalent organic group having 1 to 12 carbon atoms containing at least one selected atom, and a divalent organic group having 1 to 12 carbon atoms containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom. Examples thereof include halogenated organic groups.

Examples of the divalent hydrocarbon group having 1 to 12 carbon atoms include a linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and a divalent hydrocarbon group having 3 to 12 carbon atoms. Examples thereof include divalent aromatic hydrocarbon groups having 6 to 12 carbon atoms.

Examples of the linear or branched divalent hydrocarbon group having 1 to 12 carbon atoms include a methylene group, an ethylene group, a trimethylene group, an isopropylidene group, a pentamethylene group, a hexamethylene group and a heptamethylene group.

Examples of the divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms include a cycloalkylene group such as a cyclopropylene group, a cyclobutylene group, a cyclopentylene group and a cyclohexylene group; a cyclobutenylene group, a cyclopentenylene group and a cyclohexyl group. Examples thereof include a cycloalkenylene group such as a senylene group. The binding site of the alicyclic hydrocarbon group may be any carbon on the alicyclic.

Examples of the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms include a phenylene group, a naphthylene group and a biphenylene group. The binding site of the aromatic hydrocarbon group may be any carbon on the aromatic ring.

Examples of the divalent halogenated hydrocarbon group having 1 to 12 carbon atoms include a linear or branched divalent halogenated hydrocarbon group having 1 to 12 carbon atoms and a divalent halogenated hydrocarbon group having 3 to 12 carbon atoms. Examples thereof include a cyclic hydrocarbon group and a divalent halogenated aromatic hydrocarbon group having 6 to 12 carbon atoms.

Examples of the linear or branched divalent halogenated hydrocarbon group having 1 to 12 carbon atoms include a difluoromethylene group, a dichloromethylene group, a tetrafluoroethylene group, a tetrachloroethylene group, a hexafluorotrimethylene group and a hexachlorotrimethylene group. Examples thereof include a hexafluoroisopropylidene group and a hexachloroisopropyridene group.

As the divalent halogenated alicyclic hydrocarbon group having 3 to 12 carbon atoms, at least a part of the hydrogen atoms of the groups exemplified in the divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms are fluorine atoms. , A group substituted with a chlorine atom, a bromine atom or an iodine atom, and the like.

As the divalent halogenated aromatic hydrocarbon group having 6 to 12 carbon atoms, at least a part of the hydrogen atoms of the groups exemplified in the divalent aromatic hydrocarbon group having 6 to 12 carbon atoms are fluorine atom and chlorine. Examples thereof include a group substituted with an atom, a bromine atom or an iodine atom.

The divalent organic group having 1 to 12 carbon atoms containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom includes a hydrogen atom and a carbon atom, and an oxygen atom and / or a nitrogen atom. Examples of the valent organic group include an ether bond, a carbonyl group, an ester bond or a divalent organic group having a total carbon number of 1 to 12 having an amide bond and a hydrocarbon group.

The divalent halogenated organic group having 1 to 12 carbon atoms containing at least one atom selected from the group consisting of an oxygen atom and a nitrogen atom is specifically selected from the group consisting of an oxygen atom and a nitrogen atom. Examples thereof include a group in which at least a part of hydrogen atoms of the group exemplified in the divalent organic group having 1 to 12 carbon atoms including at least one atom is replaced with a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. ..

As the Z in the general formula (5), a single _{bond, -O -, - SO 2 -} ,> C = O or a divalent organic group having 1 to 12 carbon atoms are preferred, divalent C1-12 The hydrocarbon group of 1 to 12 or a divalent halogenated hydrocarbon group having 1 to 12 carbon atoms is more preferable, and the divalent hydrocarbon group having 1 to 12 carbon atoms is a divalent alicyclic group having 3 to 12 carbon atoms. Hydrocarbon groups are preferred.

In the general formula (6), R ⁷ , R ⁸ , Y, m, g and h are independently ^{synonymous with R 7} , R ⁸ , Y, m, g and h in the general formula (4). ^There, R ^5, R 6, Z, n, e and f have the same meanings as respectively ^R 5 in independently the general formula ^{(5), R 6, Z} , n, e and f. When m is 0, R ⁷ is not a cyano group.

The polyether has optical properties and heat resistance according to the molar ratio of the structural unit (5) and the structural unit (6) (however, the total of both ((5) + (6)) is 100). And from the viewpoint of mechanical properties, it is preferably in the range of (5) :( 6) = 50:50 to 100: 0, and in the range of (5) :( 6) = 70:30 to 100: 0. Is more preferable, and the range of (5): (6) = 80:20 to 100: 0 is even more preferable.

From the viewpoint of optical properties, heat resistance and mechanical properties, the polyether preferably contains the structural unit (5) and the structural unit (6) in an amount of 70 mol% or more in all structural units, and 95 mol in all structural units. It is more preferable to contain% or more.

<Method of synthesizing polyether>
The polyether is, for example, a compound represented by the following general formula (7) (hereinafter, also referred to as “compound (7)”) and a compound represented by the following general formula (8) (hereinafter, “compound (8)”). It can also be obtained by reacting a component (C) containing at least one compound selected from the group consisting of (also referred to as) with a component (D) containing a compound represented by the following general formula (9).

In the general formula (7), X independently represents a halogen atom, and a fluorine atom is preferable.

In the general formula (8), R ⁷ , R ⁸ , Y, m, g and h are independently ^{synonymous with R 7} , R ⁸ , Y, m, g and h in the general formula (4). Yes, X is independently synonymous with X in the general formula (7). However, when m is 0, R ⁷ is not a cyano group.

In the general formula (9), R ^a is independently a hydrogen atom, a methyl group, an ethyl group, an acetyl group, a methanesulfonyl group or a trifluoromethylsulfonyl group, a hydrogen atom among the preferred. In the general formula (9), R ^{1 to} R ^{4 and a to d are independently synonymous with R 1 to} R ⁴ and a to d in the general formula (3), respectively.

Specific examples of the compound (7) include 2,6-difluorobenzonitrile, 2,5-difluorobenzonitrile, 2,4-difluorobenzonitrile, 2,6-dichlorobenzonitrile, and 2,5-dichloro. Benzonitrile, 2,4-dichlorobenzonitrile and reactive derivatives thereof can be mentioned. In particular, 2,6-difluorobenzonitrile and 2,6-dichlorobenzonitrile are preferably used from the viewpoint of reactivity, economy and the like. It is also possible to use two or more of these compounds in combination.

Specific examples of the compound represented by the general formula (9) (hereinafter, also referred to as “compound (9)”) include 9,9-bis (4-hydroxyphenyl) fluorene and 9,9-bis (hereinafter, also referred to as “compound (9)”). 3-Phenyl-4-hydroxyphenyl) fluorene, 9,9-bis (3,5-diphenyl-4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9 Examples thereof include −bis (4-hydroxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-cyclohexylphenyl) fluorene and reactive derivatives thereof. Among the above-mentioned compounds, 9,9-bis (4-hydroxyphenyl) fluorene and 9,9-bis (3-phenyl-4-hydroxyphenyl) fluorene are preferably used. It is also possible to use two or more of these compounds in combination.

Specific examples of the compound (8) include 4,4'-difluorobenzophenone, 4,4'-difluorodiphenylsulfone, 2,4'-difluorobenzophenone, 2,4'-difluorodiphenylsulfone, 2,2. ′ -Difluorobenzophenone, 2,2′-difluorodiphenylsulfone, 3,3′-dinitro-4,4′-difluorobenzophenone, 3,3′-dinitro-4,4′-difluorodiphenylsulfone, 4,4′- Dichlorobenzophenone, 4,4'-dichlorodiphenylsulfone, 2,4′-dichlorobenzophenone, 2,4′-dichlorodiphenylsulfone, 2,2′-dichlorobenzophenone, 2,2′-dichlorodiphenylsulfone, 3,3′ Examples thereof include −dinitro-4,4′-dichlorobenzophenone and 3,3′-dinitro-4,4′-dichlorodiphenylsulfone. Among these, 4,4'-difluorobenzophenone and 4,4'-difluorodiphenyl sulfone are preferable. It is also possible to use two or more of these compounds in combination.

At least one compound selected from the group consisting of compound (7) and compound (8) is preferably contained in an amount of 80 to 100 mol%, preferably 90 to 100 mol%, in 100 mol% of the component (C). It is more preferable that the compound is used.

Further, the component (D) preferably contains a compound represented by the following general formula (10) (hereinafter, also referred to as “compound (10)”), if necessary.

The compound (9) is preferably contained in an amount of 50 to 100 mol%, more preferably 80 to 100 mol%, and 90 to 100 mol% in 100 mol% of the component (D). Is more preferable.

In the general formula (10), R ⁵ , R ⁶ , Z, n, e and f are independently ^{synonymous with R 5} , R ⁶ , Z, n, e and f in the general formula (5). Yes, ^Ra is independently synonymous with ^Ra in the general formula (9).

Examples of the compound (10) include hydroquinone, resorcinol, 2-phenylhydroquinone, 4,4'-biphenol, 3,3'-biphenol, 4,4'-dihydroxydiphenylsulfone, 3,3'-dihydroxydiphenylsulfone, 4 , 4'-dihydroxybenzophenone, 3,3'-dihydroxybenzophenone, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy) Phenyl) -1,1,1,3,3,3-hexafluoropropane and reactive derivatives thereof can be mentioned. It is also possible to use two or more of these compounds in combination.

Among the compounds mentioned above, resorcinol, 4,4'-biphenol, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy). Phenyl) -1,1,1,3,3,3-hexafluoropropane is preferable, and 4,4'-biphenol is preferably used from the viewpoint of reactivity and mechanical properties.

More specifically, the polyether can be synthesized by the method (I') or the method (II') shown below. Among these, by using the method (I'), a polyether having the above-mentioned structural unit, having a specific weight average molecular weight, and having a polystyrene-equivalent molecular weight by GPC of a certain molecular weight or less and having a small amount of low molecular weight components. Can be easily obtained.

In the method (I'), the component (D) is reacted with an alkali metal compound to obtain an alkali metal salt of the component (D), and the mixture after the step (a) and the component (C). ) Is mixed and the alkali metal salt obtained in the step (a) is reacted with the component (C), which is a method including the step (b).

Specifically, in the step (a), an alkali metal salt such as the compound (8) or the compound (10) is obtained, and in the step (b), a polyether having the structural unit (i) is obtained.

In steps (a) and (b), it is preferable to carry out each reaction in the presence of a solvent.

The method (II') is a method in which the reaction between the component (D) and the alkali metal compound is carried out in the presence of the component (C).

In this method (II'), the alkali metal salt of the component (D) reacts with the component (C) to obtain the polyether.

In the method (II'), the reaction is preferably carried out in the presence of a solvent.

When the polyether is produced by the method (I') or the method (II'), for example,
It is preferable to increase the sum of the concentrations of the component (C) and the component (D) in the reaction system (component (C) + component (D) + solvent compounding amount). Specifically, the sum of the concentrations of the component (C) and the component (D) before the start of the reaction is in the range of 20 to 50% by mass with respect to 100% by mass of the total amount of the component (C), the component (D) and the solvent. It is preferably in the range of 24 to 35% by mass, and more preferably.

When the sum of the concentrations of the component (C) and the component (D) in the reaction system is within the above range, the molecular weight distribution is narrow and the proportion of low molecular weight components having a molecular weight of 5000 or less is small, that is, the number of terminal groups. A low amount of polyether can be obtained. Therefore, by using the polyether, it is possible to obtain a film having excellent color resistance, particularly excellent light transmission in which coloring due to heating is suppressed.

Examples of the alkali metal compound used in the reaction include alkali metals such as lithium, potassium and sodium; alkali metals hydride such as lithium hydride, potassium hydride and sodium hydride; lithium hydroxide, potassium hydroxide and sodium hydroxide and the like. Alkali metal hydroxides; alkali metal carbonates such as lithium carbonate, potassium carbonate and sodium carbonate; alkali metal hydrogen carbonates such as lithium hydrogen carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate and the like can be mentioned. These can be used alone or in combination of two or more.

The amount of the metal atom in the alkali metal compound is usually 1 to 3 times equivalent, preferably 1.1 to 2 times equivalent, and more preferably 1.1 to 2 times equivalent, with respect to all -O-Ra in the component (D). Is used in an amount that is 1.2 to 1.5 times equivalent.

The solvents that can be used in the reaction include N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, γ-butyllactone, and sulfolane. , Dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, diphenyl sulfone, diphenyl ether, benzophenone, dialkoxybenzene (1 to 4 carbon atoms in the alkoxy group) and trialkoxybenzene (1 to 4 carbon atoms in the alkoxy group). Etc. can be used. Among these solvents, polar solvents having a high dielectric constant such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, diphenyl sulfone and dimethyl sulfoxide are particularly preferably used.

Further, in the reaction, a solvent that azeotropes with water such as benzene, toluene, xylene, hexane, cyclohexane, octane, chlorobenzene, dioxane, tetrahydrofuran, anisole and phenetol can be further used.

The proportion of the component (C) and the component (D) used is preferably in the range of 45 to 55 mol% when the total of the component (C) and the component (D) is 100 mol%. It is more preferably in the range of 50 to 52 mol%, further preferably more than 50 mol% and 52 mol% or less, and the component (D) is preferably in the range of 45 to 55 mol%, more preferably 48 to 50 mol%. It is more preferably 48 mol% or more and less than 50 mol%.

The reaction temperature is preferably in the range of 60 to 250 ° C, more preferably 80 to 200 ° C. The reaction time is preferably in the range of 15 minutes to 100 hours, more preferably 1 hour to 24 hours.

<Physical properties of polyether, etc.>
The polyether (I) is a polystyrene-equivalent weight measured using an HLC-8220 type GPC device (column: TSKgelα-M, developing solvent: tetrahydrofuran (hereinafter, also referred to as “THF”)) manufactured by Tosoh Corporation. The average molecular weight (Mw) is preferably in the range of 5,000 to 500,000, more preferably in the range of 15,000 to 400,000, and even more preferably in the range of 30,000 to 300,000.

The polyether (II) was measured using an HLC-8220 type GPC apparatus (column: SuperH2000 and SuperH4000, guard column: column connected with SuperH-L, developing solvent: THF) manufactured by Toso Co., Ltd., in terms of polystyrene. weight average molecular weight (Mw) is preferably in the range of ^{2.5 × 10 4 ~5.0 × 10 5} , more preferably from ^{5.0 × 10 4 ~4.0 × 10 5} , more preferably in the range of ^{7.0 × 10 4 ~3.0 × 10 5} .

Furthermore, the polyether was calculated from the molecular weight distribution curve by GPC, amounts molecular weight in terms of polystyrene measured by GPC to the total polyether occupied low molecular weight component is 5.0 × 10 ³ or less (ratio) is preferably It is 5.0% or less, more preferably 3.5% or less.

When the molecular weight of the polyether and its distribution are within the above range, the polyether is excellent in color resistance, particularly color resistance even when exposed to a high temperature. Therefore, the film containing the polyether (II) is further excellent in light transmission, particularly light transmission even when exposed to a high temperature.

The amount of the molecular weight in terms of polystyrene is occupied by low molecular weight component is 5.0 × 10 ³ or less, specifically, Tosoh H manufactured by HLC-8220 type GPC apparatus (column: SuperH2000 and SuperH4000, guard column: SuperH- L, developing solvent: THF, detector: UV254nm, flow rate: 0.6 ml / min) using the integral value in the chromatogram of the components eluted prior to the elution time of polystyrene standard samples having a molecular weight of 5.0 × 10 ³ When, it can be calculated by measuring the integral value in the chromatogram of the components eluted after the elution time of polystyrene standard samples having a molecular weight of 5.0 × 10 ^3.

The thermal decomposition temperature of the polyether measured by thermogravimetric analysis (TGA) is preferably 400 ° C. or higher, more preferably 425 ° C. or higher, still more preferably 450 ° C. or higher.

[2] Solvent When producing a transparent heat-resistant laminated film using the transparent heat-resistant resin according to the present invention, a low-boiling solvent having a boiling point of 80 ° C. or lower is used as a main solvent as a solvent for dissolving the transparent heat-resistant resin. Is preferable.

Here, "used as the main solvent" means that the low boiling point solvent according to the present invention is used in an amount of 55% by mass or more, preferably 70% by mass or more, based on the total amount of the solvent, as long as it is a mixed solvent. It is preferably used in an amount of 80% by mass or more, particularly preferably 90% by mass or more. Of course, if used alone, it will be 100% by mass.

The solvent useful for forming the resin solution (dope) when the transparent heat-resistant resin is produced by the solution casting film forming method may be a solvent that dissolves the transparent heat-resistant resin and other additives at the same time. For example, dichloromethane as a chlorine-based solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate as non-chlorine solvents, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-Methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, methanol, ethanol, Examples thereof include n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and the like.

Examples of the low boiling point solvent having a boiling point of 80 ° C. or lower according to the present invention include dichloromethane (40 ° C.), ethyl acetate (77 ° C.), methyl ethyl ketone (79 ° C.), tetrahydrofuran (66 ° C.), and acetone (56. ° C.) among the above solvents. It is preferable to contain at least one selected from 5 ° C.) and 1,3-dioxolane (75 ° C.) as the main solvent (the boiling points are shown in parentheses).

Further, as the solvent contained in the case of the mixed solvent, as long as it can dissolve the transparent heat-resistant resin according to the present invention, it can be used within a range that does not impair the effect of the present invention, and other than the solvents listed above. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, hexamethylphosphoramide, Tetramethylene sulfone, dimethyl sulfoxide, m-cresol, phenol, p-chlorophenol, 2-chloro-4-hydroxytoluene, diglime, triglime, tetraglime, dioxane, γ-butyrolactone, dioxolane, cyclopentanone, epsilon caprolactam, chloroform Etc. can be used, and two or more types may be used in combination. In addition to these solvents, a poor solvent such as hexane, heptane, benzene, toluene, xylene, chlorobenzene, or o-dichlorobenzene may be used to the extent that the transparent heat-resistant resin according to the present invention does not precipitate.

In the layer A constituting the transparent heat-resistant resin of the present invention, the layer A contains dichloromethane, and the content of dichloromethane is preferably in the range of 1 to 800 mass ppm, preferably 1 to 75 mass ppm. Is more preferable.
When it is 800 mass ppm or less, the solvent does not excessively permeate into the B layer adjacent to the A layer, and the adhesiveness and transparency with the B layer are improved. On the other hand, if it is 1 mass ppm or more, the adhesion to the B layer adjacent to the A layer is good because the dichloromethane remains appropriately.
The amount of dichloromethane residual solvent in layer A is defined by the following formula (Z).
Equation (Z)
Residual solvent amount (%) = (mass before heat treatment of casting film or film-mass after heat treatment of casting film or film) / (mass after heat treatment of casting film or film) × 100
The heat treatment for measuring the amount of residual solvent means that the heat treatment is performed at 115 ° C. for 1 hour.

[3] Additives Various additives can be added to the dope containing the transparent heat-resistant resin according to the present invention. The additives that can be used will be described below.

A thermally conductive filler may be added to the dope containing the transparent heat-resistant resin according to the present invention as long as the effects of the present invention are not impaired. As a result, the thermal conductivity of the transparent heat-resistant laminated film can be increased.

The thermally conductive filler is preferably a highly thermally conductive filler, and specific examples thereof include aluminum, copper, nickel, silica, diamond, alumina, magnesia, beryllium, boron nitride, aluminum nitride, silicon nitride, and silicon carbide. The shapes of these fillers are not particularly limited, such as spherical and plate-like ones, and needle-like ones. Among these, at least one kind of filler selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride and magnesia is preferable.

Further, it is also preferable to use fine particles of an inorganic compound or fine particles of a resin for the purpose of improving the slipperiness of the film surface. Examples of fine particles of inorganic compounds are silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silicic acid. Examples thereof include magnesium and calcium phosphate. The fine particles containing silicon are preferable in that the turbidity is low, and silicon dioxide is particularly preferable.

The average particle size of the primary particles of the fine particles is preferably in the range of 5 to 400 nm, more preferably in the range of 10 to 300 nm. These may be mainly contained as secondary aggregates having a particle size in the range of 0.05 to 0.3 μm, and particles having an average particle size in the range of 80 to 400 nm do not aggregate and are used as primary particles. It is also preferable that it is contained.

The content of these fine particles in the film is preferably in the range of 0.01 to 1% by mass, and particularly preferably in the range of 0.05 to 0.5% by mass.

In the case of a multi-layered film produced by the cocurrent spreading method, it is preferable that the surface contains fine particles in this amount.

Fine particles of silicon dioxide are commercially available under the trade names of Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 (manufactured by Nippon Aerosil Co., Ltd.) and can be used. it can.

Fine particles of zirconium oxide are commercially available under the trade names of Aerosil R976 and R811 (all manufactured by Nippon Aerosil Co., Ltd.) and can be used.

Examples of the fine particles of the resin include silicone resin, fluororesin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are preferable, and for example, trade names of Tospearl 103, 105, 108, 120, 145, 3120 and 240 (all manufactured by Toshiba Silicone Co., Ltd.). It is commercially available at and can be used.

Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of lowering the friction coefficient while keeping the haze of the film low.

Further, a dehydrating agent may be added to the dope containing the transparent heat-resistant resin. Specific examples of the dehydrating agent include acetic anhydride, propionic anhydride, butyric anhydride and other aliphatic carboxylic acid anhydrides, benzoic anhydride and other aromatic carboxylic acid anhydrides, and acetic anhydride and / or anhydride. Benzoic anhydride is preferred. The content of the dehydrating agent with respect to the transparent heat-resistant resin is preferably in the range of 0.1 to 5.0 in terms of the content of the dehydrating agent (mol) / the content of the transparent heat-resistant resin (mol). In this case, a gelation retarder such as acetylacetone may be used in combination.

Further, for example, a fluorine-based or polysiloxane-based surfactant may be added to the dope containing the transparent heat-resistant resin. When a surfactant is added, it becomes easy to obtain a film having good surface smoothness. Commercially available products may be used as the surfactant, and examples of the fluorine-based surfactant include the Megafuck (registered trademark) series of DIC Corporation and the footer (registered trademark) series of Neos Co., Ltd. Gent (registered trademark) 251 and 212MH, 250, 222F, 212D, FTX-218 and the like can be mentioned. Examples of the polysiloxane-based surfactant include BYK-307, BYK-315, BYK-320, BYK-325, BYK-330, BYK-331, BYK-332, BYK-333, BYK of Big Chemie Japan Co., Ltd. -344 and the like.

Further, for example, an antioxidant such as a phenol-based, sulfur-based, phosphoric acid-based, or phosphorous acid-based antioxidant may be added to the dope containing the transparent heat-resistant resin.

Further, various other functional materials may be added to the dope containing the transparent heat-resistant resin. The various functional materials, e.g., carbon nanotube, a conductive material such as nano-metal material, a ferroelectric material such as barium _{titanate, ZnS: Ag, ZnS: Cu} , Y 2 O 2 S: phosphor such as Eu , UV absorber, etc.

Further, a phosphorus-based flame retardant may be added to the dope containing the transparent heat-resistant resin. This makes it possible to impart flame retardancy to the transparent heat-resistant laminated film. As the phosphorus-based flame retardant, for example, ammonium polyphosphate, phosphoric acid ester, condensed phosphoric acid ester, phenoxyphosphazene compound, phosphoric acid ester amide and the like can be used. Among these phosphorus-based flame retardants, it is preferable to use a phenoxyphosphazen compound. As the phenoxyphosphazenic compound, for example, SPS-100 manufactured by Otsuka Chemical Co., Ltd. can be used. Although a halogen-type flame retardant can be mixed to impart flame retardancy, it is preferable to use a phosphorus-based flame retardant.

[4] Imidization Treatment of Film When a cast film is formed using polyamic acid, a film containing polyimide can be produced by subjecting the obtained film to an imidization treatment.

When the film is subjected to appropriate heat treatment, imidization within the polymer chain molecules and between the polymer chain molecules progresses and the mechanical properties are improved, but the more the heat treatment is performed, the more the optical film using polyimide changes the absorption wavelength. It changes deeply with it. In particular, in a film using a thin polyimide of 4.0 to 15.0 μm, the ^{higher the L *} value, the lighter the color as a whole, so that horizontal unevenness due to thickness unevenness is hard to see and the appearance is good. Since the progress of imidization is not sufficient, mechanical properties such as bending resistance and breaking strength of the film deteriorate. On the other hand, if the L ^* value is too low, the color contrast due to the uneven thickness becomes clear and the horizontal unevenness worsens, and the film using polyimide becomes partially carbonized and becomes brittle, and the film is mechanical. The characteristics recede significantly. For the above reasons, in the method for producing a film using polyimide according to the present invention, it is ^{good to set the L *} value to 30 to 55 in order to maintain good mechanical properties, and more preferably, the L ^* value is 38 to 55. It is better to set it to 54.

The L ^* value of the film was measured using SM-7-CH manufactured by Suga Test Instruments. For each sample divided into five in the film width direction, a range of 30 mm × 30 mm centered on the center position in the width direction was cut out and measured, and the average value was taken over the five points. As for the L value, the sensitivity of the detector becomes dull as the film thickness becomes thin, and appropriate evaluation cannot be performed. Therefore, the minimum L value is 50 μm or more for a film having a film thickness of 50 μm or more and 50 μm or more for a film having a film thickness of less than 50 μm. It is a value measured by stacking the number of sheets.

Regarding the method of heat treatment for obtaining a film having an L ^* value of the film of 30 to 55, for example, a method of adjusting the amount of heat treatment using a known means such as hot air or an electric heater (for example, an infrared heater). Can be mentioned.

In the method for producing a film using a polyimide according to the present invention, a solution of a polyamic acid containing no ring-closing catalyst and a dehydrating agent is cast to form a film, heat-dried on a support, and then the film is formed from the support. A thermal ring-closing method can be used in which the film is imidized by peeling the film and further performing a dry heat treatment at a high temperature. Further, a solution of polyamic acid containing a ring-closing catalyst and a dehydrating agent is cast to form a film, and imidization is partially promoted on the support to form a film, and then the film is peeled off from the support. It is also possible to use a chemical ring-closing method in which heat-drying / imidization and heat treatment are performed. As the ring closure catalyst, the above-mentioned tertiary amine or the like can be used.

In the thermal ring closure method, heat treatment can be performed by using, for example, an infrared heater.

As the infrared heater, for example, a heater body formed so as to surround the filament with an inner tube is covered with an outer tube so that a cooling fluid can flow between the heater body and the outer tube. The filament is energized and heated to 700-1200 ° C. and emits infrared rays having a peak at a wavelength of around 3 μm. The inner tube and outer tube are made of quartz glass, crown glass borosilicate, or the like, and function as a filter that passes infrared rays having a wavelength of 3.5 μm or less and absorbs infrared rays having a wavelength exceeding 3.5 μm. In such an infrared heater, when infrared rays having a peak in the wavelength of about 3 μm are emitted from the filament, infrared rays having a wavelength of 3.5 μm or less are emitted to the film through the inner tube or the outer tube. By irradiating infrared rays of this wavelength, the mixed solvent in the film can be efficiently evaporated, and the polyamic acid in the film can be imidized. The inner tube and outer tube absorb infrared rays having a wavelength exceeding 3.5 μm, but are cooled by the cooling fluid flowing through the flow path, so that the temperature can be maintained below the ignition point of the mixed solvent that evaporates from the film. It is possible.

In the method for producing a film using polyimide according to the present invention, any of the above ring-closing methods may be adopted, but the chemical ring-closing method requires equipment for containing a ring-closing catalyst and a dehydrating agent in a polyamic acid solution. However, it can be said to be a more preferable method in that a film having self-supporting property can be obtained in a short time.

<Metal layer>
The transparent heat-resistant laminated film of the present invention has layers A and B and a metal layer containing the above-mentioned transparent heat-resistant resin in this order.
The metal layer differs depending on the application of the transparent heat-resistant laminated film, and in the case of a transparent flexible printed substrate application, the metal layer is preferably copper foil from the viewpoint of cost reduction, but aluminum, gold, silver, and aluminum. , Nickel, tin and other metal foils may be used.
Further, in the case of a transparent electrode substrate application, in addition to ITO as a metal layer (transparent conductive layer), silver nanowires, metal mesh (silver, copper) and the like are used as the metal layer.

[5] Method for Producing Transparent Heat-Resistant Laminated Film A specific example of the method for producing a transparent heat-resistant laminated film will be described below.

As a method for producing the transparent heat-resistant laminated film of the present invention,
(1) A doping for forming the A layer and a doping for forming the B layer are prepared respectively, and these two types of doping are co-cast to prepare a base film composed of the A layer and the B layer. A method of further forming a metal layer on the B layer of the base film,
(2) A dope for forming the A layer and a dope for forming the B layer are prepared, and these two types of dopes are individually formed to form the A layer and the B layer, respectively. , A method of producing a base film composed of the A layer and the B layer by laminating the A layer and the B layer via an adhesive, and further forming a metal layer on the B layer of the base film.
Can be mentioned.

The method (1) above will be described in detail.
As the method (1), a step (dope) of adjusting a dope in which the transparent heat-resistant resin contained in the A layer is dissolved in a solvent and a dope in which the transparent heat-resistant resin contained in the B layer is dissolved in a solvent are prepared. A step (preparation step), a step (casting step) of forming a casting film (also referred to as a web) by co-spreading two types of dope prepared in the doping adjusting step on a support, and the casting film. It is preferable to have a step of peeling from the support (peeling step). Further, a step of evaporating the solvent from the casting film on the support (solvent evaporation step), a step of drying the obtained film (first drying step), a step of stretching the film (stretching step), and a step after stretching. A step of further drying the film (second drying step), a step of winding the obtained base film composed of the A layer and the B layer (winding step), and a step of heat-treating the film to imidize it if necessary. It is preferably performed by (heating step) or the like. By further forming a metal layer on the B layer of the base film thus obtained, the transparent heat-resistant laminated film of the present invention is produced.

Hereinafter, each step will be specifically described.

[5-1] Dope Preparation Step As described above, this is a step of preparing at least two types of dope having different formulations in which the transparent heat-resistant resin is dissolved in a solvent. As the solvent, the above-mentioned low boiling point solvent having a boiling point of 80 ° C. or lower is used as the main solvent. At that time, in order to prepare at least two kinds of dopes having different formulations in which the transparent heat-resistant resin is dissolved in a solvent, they may be dissolved in the same solvent or in different solvents. However, from the viewpoint of avoiding the influence of mixing the solvents between the layers, it is preferable to dissolve them in the same solvent.

Then, the prepared dope is guided to a filter by a liquid feed pump or the like and filtered.

The gel-like foreign matter in the dope is removed by filtering the dope at a temperature of + 5 ° C. or higher at a boiling point of the low boiling point solvent at 1 atm. The preferred temperature range is 45-120 ° C, more preferably 45-70 ° C, even more preferably 45-55 ° C.

[5-2] Flowing film forming step This is a step of forming a casting film by co-spreading the two types of dope prepared above on a support.

In the present invention, it is preferable to use the following devices and methods for co-inflow.

FIG. 1 is a schematic view showing a part of the apparatus used for co-flow spreading according to the present invention.

The layers A and B constituting the transparent heat-resistant laminated film of the present invention are obtained by laminating dope (dope 1 and dope 2) by co-flowing, and in FIG. 1, the dope 1 and dope 2 are laminated. An example of forming a two-layer base film will be described.

As shown in the figure, the hypersalivation has a plurality of slits 13 and 14 in the base portion 11 of the hypersalivation die 10, and the slits 13 and 14 to the A layer are simultaneously formed on the metal support 16. By casting the dope 1 (17) and the dope 2 (18) for the B layer, a multilayer structure web (casting film) 20 having a structure in which the B layer 22 is provided on the A layer 21 is formed.

The multilayer structure web 20 is then vaporized with a solvent to form a film, which is peeled off from the metal support 16 to form a base film composed of layers A and B.

The surface temperature of the metal support is preferably 10 to 70 ° C., the temperature of the solution is preferably 25 to 60 ° C., and the temperature of each solution is preferably the same as or higher than the temperature of the support.

A more preferred range for the temperature of the metal support depends on the solvent used, but a more preferred range for the solution temperature is 30-50 ° C.

For casting, a plurality of dopes may be prepared and the plurality of dope may be cast on a smooth band as a support or on a drum to form a film.

In this case, two or more types of dope may be flowed onto the support at the same time, or may be separately flown onto the support. In the case of the sequential casting method in which the dope is cast separately, the dope on the support side can be cast first, dried on the support to some extent, and then cast on top of it.
Unlike the method of applying on a dried film, these methods of forming a film by co-rolling or sequential casting make the boundary between each layer of the laminated structure unclear, and the laminated structure is clarified by observing the cross section. It has the characteristic that it may not be divided into two, and has the effect of improving the adhesion between each layer.

As the co-infusion method, a known co-infusion method can be used. For example, a film may be produced by casting and laminating a dope containing a transparent heat-resistant resin from a plurality of flow ports provided at intervals in the traveling direction of the metal support, for example, Japanese Patent Application Laid-Open No. 61. The methods described in JP-A-158414, JP-A-1-122419, JP-A-11-198285, etc. can be applied. Further, a dope containing a transparent heat-resistant resin may be cast from two casting ports to form a film. For example, JP-A-60-27562, JP-A-61-94724, JP-A-61- It can be carried out by the methods described in JP-A-974245, JP-A-61-104813, JP-A-61-158413, and JP-A-6-134933.

The metal support in casting is preferably a mirror-finished surface, and the support is a stainless steel belt or a drum whose surface is plated with a casting, or a metal support such as a stainless steel belt or a stainless steel belt. Is preferably used. The width of the cast can be in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, more preferably in the range of 2 to 2.8 m. The support does not have to be made of metal.

The traveling speed of the metal support is not particularly limited, but is usually 5 m / min or more, preferably 10 to 180 m / min, and particularly preferably 80 to 150 m / min. The higher the traveling speed of the metal support, the easier it is for companion gas to be generated, and the more remarkable the occurrence of thickness unevenness due to disturbance.

The traveling speed of the metal support is the moving speed of the outer surface of the metal support.

The die has a shape that gradually becomes thinner toward the discharge port in a cross section perpendicular to the width direction. Specifically, the die usually has tapered surfaces on the downstream side and the upstream side in the traveling direction of the lower portion, and a discharge port is formed in a slit shape between the tapered surfaces. A metal die is preferably used, and specific examples thereof include stainless steel and titanium. In the present invention, when producing films having different thicknesses, it is not necessary to change to dies having different slit gaps.

It is preferable to use a pressure die that can adjust the slit shape of the base portion of the die and can easily make the thickness uniform. The pressure die includes a coat hanger die, a T die, and the like, and any of them is preferably used. Even when films of different thicknesses are continuously produced, the discharge rate of the die is maintained at a substantially constant value. Therefore, when a pressure die is used, conditions such as extrusion pressure and shear rate are also omitted. It is maintained at a constant value. Further, in order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the doping amount may be divided and laminated.

The discharge rate of the dope from the die is preferably 200 to 720 g / m ² , and more preferably 400 to 650 g / m ² . In the present invention, it is preferable that the dope discharge amount from the die is maintained at a substantially constant value within the above range even when films having different thicknesses are continuously produced. When the discharge amount is 200 g / m ² or more, the cast film is less susceptible to disturbances such as vibration and wind, so that uneven thickness can be sufficiently prevented. When the discharge amount is 720 g / m ² or less, shrinkage is unlikely to occur excessively, and thickness unevenness due to shrinkage does not occur, so that thickness unevenness can be sufficiently prevented.

[5-3] Solvent Evaporation Step The solvent evaporation step is a pre-drying step performed on a metal support, heating the cast film on the metal support, and evaporating the solvent.

To evaporate the solvent, for example, a method of blowing heating air from the casting film side and the back side of the metal support with a dryer, a method of transferring heat from the back surface of the metal support with a heating liquid, and a method of transferring heat from the front and back by radiant heat. And so on. A method of appropriately selecting and combining them is also preferable. The surface temperature of the metal support may be the same as a whole or may differ depending on the position.

In the present invention, the multi-layered web is dried on the metal support at a temperature of (T-1) ° C. or lower, where the boiling point of the low boiling point solvent according to the present invention is T ° C. This is a more preferable embodiment from the viewpoint of suppressing the diffusion of the heat-resistant resin and remarkably suppressing the mixing of the materials at the layer interface. It is preferably (T-5) ° C. or lower, more preferably (T-10) ° C. or lower. Therefore, when the heating air is blown by the dryer, the temperature of the heating air is preferably in the range of 10 to 70 ° C.

In the method of heating the metal support, a higher temperature is preferable because the drying speed of the (casting film) of the multilayer structure web can be increased, but if it is too high, the casting film foams or the flatness deteriorates. Therefore, it is preferable to adjust the temperature appropriately depending on the resin and solvent used.

In the solvent evaporation step, it is preferable to dry the casting film until the residual solvent amount becomes 10 to 150% by mass from the viewpoint of the peelability of the casting film and the transportability after peeling.

In the present invention, the amount of residual solvent can be expressed by the following formula.

Residual solvent amount (mass%) = {(MN) / N} x 100
Here, M is the mass of the casting film (film) at a predetermined time point, and N is the mass of M when it is dried at 115 ° C. for 1 hour. In particular, M when calculating the amount of residual solvent achieved in the solvent evaporation step is the mass of the cast film immediately before the peeling step.

[5-4] Peeling Step The casting film in which the solvent has evaporated on the metal support is peeled off at the peeling position.

The peeling tension when peeling the metal support and the casting film is usually in the range of 60 to 400 N / m, but if wrinkles are likely to occur during peeling, the metal support is peeled at a tension of 190 N / m or less. Is preferable.

In the present invention, the temperature at the peeling position on the metal support is preferably in the range of −50 to 60 ° C, more preferably in the range of 10 to 40 ° C, and in the range of 15 to 40 ° C. Is the most preferable.

The peeled film may be sent directly to the stretching step, or may be sent to the stretching step after being sent to the first drying step so as to achieve a desired residual solvent amount. In the present invention, from the viewpoint of stable transport in the stretching step, it is preferable that the film is sequentially fed to the first drying step and the stretching step after the peeling step.

[5-5] First Drying Step The first drying step is a drying step of heating the film and further evaporating the solvent. The drying means is not particularly limited, and for example, hot air, infrared rays, heating rollers, microwaves and the like can be used. From the viewpoint of convenience, it is preferable to dry the film with hot air or the like while transporting the film with rollers arranged in a staggered pattern. The drying temperature is preferably in the range of 30 to 200 ° C. in consideration of the amount of residual solvent, the expansion / contraction rate during transportation, and the like.

[5-6] Stretching Step By stretching the transparent heat-resistant laminated film peeled from the metal support, the thickness, flatness, orientation, etc. of the film can be controlled.

In the method for producing a transparent heat-resistant laminated film according to the present invention, it is preferable to stretch in the longitudinal direction and / or the width direction.

The stretching operation may be performed in multiple stages. Further, when biaxial stretching is performed, simultaneous biaxial stretching may be performed, or biaxial stretching may be performed step by step. In this case, the term “stepwise” means, for example, that stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any of the steps. Is also possible.

That is, for example, the following stretching steps are also possible:
・ Stretching in the longitudinal direction → Stretching in the width direction → Stretching in the longitudinal direction → Stretching in the longitudinal direction ・ Stretching in the width direction → Stretching in the width direction → Stretching in the longitudinal direction → Stretching in the longitudinal direction Also includes the case of stretching in one direction and contracting the other with relaxation of tension.

The amount of residual solvent at the start of stretching is preferably in the range of 2 to 50% by mass.

When the amount of the residual solvent is 2% by mass or more, the film thickness deviation becomes small, which is preferable from the viewpoint of flatness, and when it is 50% by mass or less, the unevenness of the surface is reduced and the flatness is improved, which is preferable.

In the method for producing a transparent heat-resistant laminated film of the present invention, the film may be stretched in the longitudinal direction and / or the width direction, preferably in the width direction, so that the thickness after stretching is within a desired range. When the lowest Tg of the glass transition points (Tg) of the film is TgL and the highest Tg is TgH, it is preferable to stretch the film in a temperature range of (TgL-200) to (TgH + 50) ° C. When stretched in the above temperature range, the stretching stress can be reduced and the haze becomes low. In addition, a transparent heat-resistant laminated film containing polyimide, which suppresses the occurrence of breakage and is excellent in flatness and colorability of the film itself, can be obtained. The stretching temperature is more preferably in the range of (TgL-150) to (TgH + 40) ° C.

In the method for producing a transparent heat-resistant laminated film of the present invention, a self-supporting film peeled from a support can be stretched in the longitudinal direction by controlling the traveling speed with a stretching roller. The stretching ratio in the longitudinal direction is preferably 1.03 to 2.00 times, more preferably 1.10 to 1.80 times, still more preferably 1.20 to 1.60 times in the temperature range of 30 to 250 ° C. is there.

In order to stretch in the width direction, for example, the width of both ends of the width of the film is held by a clip or a pin in the width direction by performing a total drying treatment or a part of the drying treatment as shown in Japanese Patent Application Laid-Open No. 62-46625. A method of drying while drying (called a tenter method), in particular, a tenter method using a clip is preferably used.

It is preferable that the film stretched in the longitudinal direction or the unstretched film is introduced into the tenter with both ends in the width direction gripped by the clip, and is stretched in the width direction while traveling together with the tenter clip. The draw ratio in the width direction is not particularly limited, but is preferably 1.03 to 2.00 times, more preferably 1.10 to 1.80 times, and further preferably 1.20 to 1.20 times in the temperature range of 30 to 300 ° C. It is 1.60 times.

When stretching in the width direction, it is preferable to stretch the film in the width direction at a stretching rate of 50 to 1000% / min from the viewpoint of improving the flatness of the film.

When the stretching speed is 50% / min or more, the flatness is improved and the film can be processed at high speed, which is preferable from the viewpoint of production suitability. When the stretching speed is 1000% / min or less, the film breaks. It can be processed without any problem, which is preferable.

A more preferred stretching rate is in the range of 100-500% / min. The stretching rate is defined by the following formula.

Stretching rate (% / min) = [(d ₁ / d ₂ ) -1] × 100 (%) / t
(In the above formula, d ₁ is the width dimension of the stretched resin film in the stretching direction, d ₂ is the width dimension of the resin film before stretching in the stretching direction, and t is the time required for stretching (min). Is.)
In the stretching step, holding / relaxation is usually performed after stretching. That is, in this step, it is preferable to perform a stretching step of stretching the film, a holding step of holding the film in a stretched state, and a relaxing step of relaxing the film in the stretching direction in these orders. In the holding step, the stretching at the stretching ratio achieved in the stretching step is held at the stretching temperature in the stretching step. In the relaxation step, the stretching in the stretching step is held in the holding step, and then the tension for stretching is released to relax the stretching. The relaxation step may be performed at a temperature equal to or lower than the stretching temperature in the stretching step.

[5-7] Second Drying Step Next, the stretched film is heated and dried. When the film is heated by hot air or the like, a means for preventing the mixing of used hot air by installing a nozzle capable of exhausting used hot air (air containing a solvent or wet air) is also preferably used. The hot air temperature is more preferably in the range of 40 to 350 ° C. The drying time is preferably about 5 seconds to 30 minutes, more preferably 10 seconds to 15 minutes.

Further, the heating and drying means is not limited to hot air, and for example, infrared rays, heating rollers, microwaves and the like can be used. From the viewpoint of convenience, it is preferable to dry the film with hot air or the like while transporting the film with rollers arranged in a staggered pattern. The drying temperature is more preferably in the range of 40 to 350 ° C. in consideration of the amount of residual solvent, the expansion / contraction rate during transportation, and the like.

In the second drying step, it is preferable to dry the film until the residual solvent amount becomes 0.5% by mass or less.

[5-8] Winding Step The winding step is a step of winding the obtained film and cooling it to room temperature. The winder may be a generally used one, and can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress.

The thickness of the film is not particularly limited, and is preferably in the range of 5 to 200 μm, particularly preferably in the range of 7 to 50 μm.

In the winding step, both ends of the film sandwiched by a tenter clip or the like when stretched and conveyed may be slit. The slit end is preferably reused as a return material. Here, the return material refers to a portion of the film formed into a film that is reused as a raw material for some reason, such as the slit end (also referred to as an ear) and the feeding / ending of manufacturing. Examples include the full width portion of the film located in, and a film that is incompatible as a product due to appearance problems such as scratches and streaks. The slit end of the film is finely cut to a width of 1 to 30 mm, and then dissolved in a solvent for reuse.

The ratio of the portion of the molded film that is reused as the return material is preferably in the range of 10 to 90% by mass, more preferably in the range of 20 to 80% by mass, and further preferably in the range of 30 to 70% by mass. Is inside.

The input amount varies slightly depending on the amount of the return material generated during or finally in the film forming process, but usually, the mixing ratio of the return material with respect to the total solid content in the dope is about 10 to 50% by mass, preferably about 10 to 50% by mass. It is about 15 to 40% by mass. It is preferable that the mixing ratio of the return material is as constant as possible from the viewpoint of production stability.

Each step from the solvent evaporation step to the winding step described above may be carried out in an air atmosphere or an inert gas atmosphere such as nitrogen gas. Further, each step, particularly the drying step and the stretching step, is carried out in consideration of the explosive limit concentration of the solvent in the atmosphere.

[5-9] Heating Step After the winding step, the film dried in the second drying step is further heat-treated in order to promote imidization within the polymer chain molecule and between the polymer chain molecules to improve the mechanical properties. It is also possible to carry out a heating step.

Further, even when the dope is prepared using polyimide (imidization rate 100%) or the film imidization rate becomes 100% by performing the second drying step, the residual stress of the film is obtained. It is also preferable to carry out a heating step for the purpose of alleviating the above.

The second drying step may also serve as a heating step.

The heating means is performed by using known means such as hot air, an electric heater, and a microwave. As the electric heater, the infrared heater described above can be used.

As for the heat treatment conditions ^{, the heater output, hot air temperature, etc. are adjusted so that the film L *} value is 30 to 55, and the final treatment conditions are in the temperature range of 200 to 450 ° C., in the range of 30 seconds to 1 hour. It is preferable to carry out as appropriate. Thereby, the dimensional stability of the polyimide film can be improved. In the heating step, if the film is rapidly heated, problems such as an increase in surface defects occur. Therefore, it is preferable to appropriately select the heating method. Further, the heating step is preferably performed in a low oxygen atmosphere.

If the heating temperature in the second drying step and the heating step exceeds 450 ° C., the energy required for heating becomes very large, which increases the manufacturing cost and further increases the environmental load. Therefore, the heating temperature is 450 ° C. It is preferable to make the following.

After the winding step, before or after the heating step, a step of slitting the widthwise end portion of the polyimide film, a step of removing static electricity from the polyimide film when it is charged, and the like are further performed. It may be.

[5-10] Metal Layer Formation Step When the transparent heat-resistant laminated film of the present invention is used, for example, as a transparent flexible printed substrate described later, the metal layer is a base film in which A layer and B layer are laminated. It is formed by crimping a metal foil on top with an adhesive.
Examples of the adhesive used here include acrylic, polyimide, and epoxy adhesives.
Further, when the transparent heat-resistant laminated film of the present invention is used as a transparent electrode substrate, which will be described later, for example, in addition to ITO as a metal layer (transparent conductive layer), silver nanowires, metal meshes (silver, copper), etc. Metal layer is used. In the case of ITO, a physical vapor deposition method such as a sputtering method is preferable, and in the case of silver nanowires, a composition for forming a transparent conductive layer containing metal nanowires is applied onto the base film. Can be formed. Further, in the case of a metal mesh, fine metal lines are formed in a grid pattern on the base film. Details will be described later.

As the method (2), the above steps [5-1] to [5-9] are performed on the A layer and the B layer, respectively, and the A layer single layer film and the B layer single layer are formed. Films are prepared, respectively, and layers A and B are adhered via, for example, an optical adhesive such as an optical clear adhesive (OCA) or a pressure sensitive adhesion (PSA). A base film composed of A layer and B layer is produced by adhering with a heat-curable or photo-curable adhesive. After that, a transparent heat-resistant laminated film can be produced on the B layer through the above steps [5-10].

[6] Transparent flexible printed circuit board, transparent electrode substrate]
[6-1] Transparent Flexible Printed Substrate The transparent flexible printed substrate of the present invention can be obtained by forming an electric circuit on the transparent heat-resistant laminated film of the present invention. Examples of the transparent flexible printed circuit board include flexible printed circuit boards (FPCs).

[6-2] Transparent Electrode Substrate The transparent heat-resistant laminated film of the present invention is also suitable as a transparent electrode substrate.
The transparent electrode substrate has at least a base film (hereinafter, also referred to as a base material) composed of layers A and B of the present invention, and a metal layer (hereinafter, also referred to as a transparent conductive layer).
The transparent conductive layer preferably has conductivity, transparency, visibility, and patternability. For example, in addition to ITO (indium-tin composite oxide), metal nanowires such as silver nanowires and metal meshes such as metal mesh (silver, copper) can be mentioned.
Further, the base film preferably has high transparency (high transmittance, low haze).

Further, the resistance value of the transparent conductive layer of the present application is in the range of 0.01 to 150 Ω / □. More preferably, the resistance value of the transparent conductive layer is in the range of 0.1 to 100 Ω / □. When the resistance value of the transparent conductive layer is 0.01 Ω / □ or more, durability against keystrokes is obtained, and when the resistance value is 150 Ω / □ or less, curling can be suppressed, which is preferable.

(ITO)
When ITO (indium-tin composite oxide) is used as the transparent conductive layer, the tin oxide (SnO ₂ ) content in the metal oxide is the total amount of tin oxide and indium oxide (In ₂ O _3). On the other hand, it is preferably in the range of 0.5 to 15% by mass, preferably in the range of 3 to 15% by mass, more preferably in the range of 5 to 12% by mass, and 6 to 12% by mass. It is more preferred that it is not in 12% by mass of leaves. If the amount of tin oxide is too small, the durability of the ITO film may be inferior. Further, if the amount of tin oxide is too large, the ITO film is difficult to crystallize, and the transparency and the stability of the resistance value may not be sufficient.

The ITO in the present specification may be a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of the additional component include metal elements other than In and Sn, and specifically, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W and Fe. , Pb, Ni, Nb, Cr, Ga, and combinations thereof. The content of the additional component is not particularly limited, but may be 3% by mass or less.

The transparent conductive layer may have a structure in which a plurality of indium-tin composite oxide layers having different amounts of tin are laminated. In this case, the ITO film may have two layers or three or more layers.

When ITO is used as the transparent conductive layer, the method for forming the transparent conductive layer is not particularly limited, and from the viewpoint of layer thickness uniformity and film formation efficiency, a chemical vapor deposition method (CVD) or a physical vapor deposition method is used. A vacuum film forming method such as (PVD) is preferably adopted. Among them, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, an ion plating method, and an electron beam vapor deposition method is preferable, and a sputtering method is particularly preferable.

From the viewpoint of obtaining a long laminated body, it is preferable that the transparent conductive layer is formed while transporting the film base material by, for example, a roll-to-roll method or the like.

As the sputtering target, a target having the above ITO composition can be preferably used. In sputter film formation, first, the vacuum degree (reaching vacuum degree) in the sputtering apparatus is preferably ^{exhausted to 1 × 10 -3} Pa or less, more preferably 1 × 10 ^-4 Pa or less, and then the inside of the sputtering apparatus is exhausted. It is preferable to create an atmosphere in which impurities such as water and organic gas generated from the base material are removed. This is because the presence of water and organic gas terminates dangling bonds generated during sputter film formation and hinders crystal growth of conductive oxides such as ITO.

In the sputtering apparatus exhausted in this way, along with an inert gas such as Ar, oxygen gas or the like which is a reactive gas is introduced as necessary, and while transporting the base material, sputtering is performed under a reduced pressure of 1 Pa or less. Make a membrane. The pressure at the time of film formation is preferably in the range of 0.05 to 1 Pa, and more preferably in the range of 0.1 to 0.7 Pa. If the film forming pressure is too high, the film forming speed tends to decrease, and conversely, if the pressure is too low, the discharge tends to be unstable.

The substrate temperature when the ITO is sputter-deposited is preferably in the range of −10 ° C. to 190 ° C., more preferably in the range of −10 ° C. to 150 ° C.

(Metal nanowires)
The metal nanowire is a conductive substance whose material is metal, whose shape is needle-shaped or thread-shaped, and whose diameter is nanometer-sized. The metal nanowires may be linear or curved. If a transparent conductive layer made of metal nanowires is used, the metal nanowires have a mesh shape, so that a good electric conduction path can be formed even with a small amount of metal nanowires, and electric resistance can be obtained. A transparent conductive film having a small size can be obtained. Further, since the metal nanowires have a mesh shape, an opening can be formed in the gap between the meshes to obtain a transparent conductive film having high light transmittance.

The ratio of the thickness d to the length L (aspect ratio: L / d) of the metal nanowire is preferably in the range of 100 to 100,000, more preferably in the range of 50 to 100,000. Yes, particularly preferably in the range of 100 to 10,000. When metal nanowires having such a large aspect ratio are used, the metal nanowires can cross each other well, and a small amount of metal nanowires can exhibit high conductivity. As a result, a transparent conductive film having high light transmittance can be obtained.

In the present specification, the "thickness of the metal nanowire" means the diameter of the metal nanowire when the cross section is circular, and the minor diameter when the cross section of the metal nanowire is elliptical. When it is a polygon, it means the longest diagonal line. The thickness and length of the metal nanowires can be confirmed by a scanning electron microscope or a transmission electron microscope.
The thickness of the metal nanowires is preferably less than 500 nm, more preferably less than 200 nm, particularly preferably in the range of 10 to 100 nm, and most preferably in the range of 10 to 50 nm. Within such a range, a transparent conductive layer having high light transmittance can be formed.

The length of the metal nanowires is preferably in the range of 2.5 to 1000 μm, more preferably in the range of 10 to 500 μm, and particularly preferably in the range of 20 to 100 μm. Within such a range, a transparent electrode substrate having high conductivity can be obtained.
As the metal constituting the metal nanowire, any suitable metal can be used as long as it is a highly conductive metal. Examples of the metal constituting the metal nanowire include silver, gold, copper, nickel and the like. Further, a material obtained by plating (for example, gold plating) these metals may be used. Of these, silver or copper is preferable from the viewpoint of conductivity.

Any suitable method can be adopted as the method for producing the metal nanowires. For example, a method of reducing silver nitrate in a solution, a method of applying an applied voltage or an electric current to the surface of the precursor from the tip of the probe, drawing out a metal nanowire at the tip of the probe, and continuously forming the metal nanowire. Can be mentioned. In the method of reducing silver nitrate in a solution, silver nanowires can be synthesized by liquid-phase reduction of a silver salt such as silver nitrate in the presence of a polyol such as ethylene glycol and polyvinylpyrrolidone.
Uniform size silver nanowires are available, for example, from Xia, Y. et al. etal. , Chem. Mater. (2002), 14, 4736-4745, Xia, Y. et al. etal. , Nano letters (2003) 3 (7), 955-960, can be mass-produced.

The transparent conductive layer can be formed by applying a composition for forming a transparent conductive layer containing the metal nanowires on the base film. More specifically, a dispersion liquid (composition for forming a transparent conductive layer) in which the metal nanowires are dispersed in a solvent is applied onto the base film, and then the coated layer is dried to form a transparent conductive layer. Can be formed.
Examples of the solvent include water, alcohol solvents, ketone solvents, ether solvents, hydrocarbon solvents, aromatic solvents and the like. From the viewpoint of reducing the environmental load, it is preferable to use water.
The dispersion concentration of the metal nanowires in the composition for forming a transparent conductive layer containing the metal nanowires is preferably in the range of 0.1 to 1% by mass. Within such a range, a transparent conductive layer having excellent conductivity and light transmission can be formed.

The composition for forming a transparent conductive layer containing the metal nanowires may further contain any suitable additive depending on the purpose. Examples of the additive include a corrosion inhibitor that prevents corrosion of metal nanowires, a surfactant that prevents aggregation of metal nanowires, and the like. The type, number and amount of additives used can be appropriately set according to the purpose. In addition, the composition for forming a transparent conductive layer may contain any suitable binder resin, if necessary, as long as the effects of the present invention can be obtained.

Any suitable method can be adopted as a method for applying the composition for forming a transparent conductive layer containing the metal nanowires. Examples of the coating method include spray coating, bar coating, roll coating, die coating, inkjet coating, screen coating, dip coating, letterpress printing method, intaglio printing method, gravure printing method and the like.
As a method for drying the coating layer, any suitable drying method (for example, natural drying, blast drying, heat drying) can be adopted. For example, in the case of heat drying, the drying temperature is typically in the range of 100 to 200 ° C., and the drying time is typically in the range of 1 to 10 minutes.

When the transparent conductive layer contains metal nanowires, the thickness of the transparent conductive layer is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 3 μm, and particularly preferably in the range of 0.05 to 3 μm. Is in the range of 0.1 to 1 μm. Within such a range, a film having excellent conductivity and light transmission can be obtained.
When the transparent conductive layer contains metal nanowires, the total light transmittance of the transparent conductive layer is preferably 85% or more, more preferably 90% or more, still more preferably 95% or more.

(Metal mesh)
The transparent conductive layer containing the metal mesh is formed by forming fine metal lines in a grid pattern on a base film (base material) composed of the A layer and the B layer according to the present invention. As the metal constituting the metal mesh, any suitable metal can be used as long as it is a highly conductive metal. Examples of the metal constituting the metal mesh include silver, gold, copper, nickel and the like. Further, a material obtained by plating (for example, gold plating) these metals may be used. Of these, copper is preferable, and migration phenomenon is unlikely to occur, and it is also preferable from the viewpoint of suppressing disconnection at the time of keystroke.

The transparent conductive layer containing the metal mesh can be formed by any suitable method. For the transparent conductive layer, for example, a photosensitive composition containing a silver salt (composition for forming a transparent conductive layer) is applied onto the laminate, and then exposure treatment and development treatment are performed to form a fine metal wire in a predetermined pattern. It can be obtained by forming in. Further, the transparent conductive layer can also be obtained by printing a paste containing metal fine particles (composition for forming a transparent conductive layer) on a predetermined pattern.
Details of such a transparent conductive layer and a method for forming the transparent conductive layer are described in, for example, Japanese Patent Application Laid-Open No. 2012-18634, and the description thereof is incorporated herein by reference. Further, as another example of the transparent conductive layer made of a metal mesh and the method for forming the transparent conductive layer, the transparent conductive layer described in JP-A-2003-331654 and the method for forming the transparent conductive layer can be mentioned.
When the transparent conductive layer contains a metal mesh, the thickness of the transparent conductive layer is preferably in the range of 0.1 to 30 μm, more preferably in the range of 0.1 to 9 μm.
When the transparent conductive layer contains a metal mesh, the transmittance of the transparent conductive layer is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more.

The transparent electrode substrate may optionally include any other suitable other layer. Examples of the other layers include a hard coat layer, an antistatic layer, an antiglare layer, an antireflection layer, and a color filter layer.

[7] LED Lighting Device The lighting device of the present invention is not particularly limited as long as it uses the transparent heat-resistant laminated film produced by the method for producing the transparent heat-resistant laminated film of the present invention. ..

Specifically, the LED lighting device includes a step of preparing a flexible printed substrate having a metal portion using the transparent heat-resistant laminated film according to the present invention, a step of fixing an LED chip on the substrate, and a step of covering the metal portion. As described above, in the step of applying the coating composition for the barrier layer to form the barrier layer, the composition for the wavelength conversion layer containing the transparent resin and the phosphor particles is applied so as to cover the LED chip, and the wavelength conversion layer is formed. It is formed by a step of forming or the like.

[8] Organic Electroluminescent Display Device In the organic electroluminescent display device of the present invention, a transparent heat-resistant laminated film produced by the method for producing a transparent heat-resistant laminated film of the present invention and a base material for a flexible display provided with the transparent heat-resistant laminated film are used. It is preferable to have it.

Regarding the outline of the organic EL element applicable to the organic electroluminescence display device of the present invention, for example, Japanese Patent Application Laid-Open No. 2013-157634, Japanese Patent Application Laid-Open No. 2013-168552, JP-A-2013-177361, JP-A-2013- 187211, JP2013-191644, JP2013-191804, JP2013-225678, JP2013-235994, JP2013-243234, JP2013-243236 Japanese Patent Application Laid-Open No. 2013-242366, Japanese Patent Application Laid-Open No. 2013-243371, Japanese Patent Application Laid-Open No. 2013-245179, Japanese Patent Application Laid-Open No. 2014-003249, Japanese Patent Application Laid-Open No. 2014-003299, Japanese Patent Application Laid-Open No. 2014-013910, Examples thereof include the configurations described in JP-A-2014-017493 and JP-A-2014-017494.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

The structures of the compounds used in the following examples are listed below.

The sources of commercially available products of the above compounds are as follows.
Acid anhydride 1: Daikin Industries, Ltd. Diamine 1: Daikin Industries, Ltd.

(Preparation of polyimide film [1])
2,2-bis (3,4-dicarboxyphenyl) -1,1,1, in a four-necked flask equipped with a dry nitrogen gas introduction tube, a cooler, a Dean-Stark aggregator filled with toluene, and a stirrer. Add 25.59 g (57.6 mmol) of 3,3,3-hexafluoropropane dianhydride (acid anhydride 1) (manufactured by Daikin Industries, Ltd.) to N, N-dimethylacetamide (134 g) at room temperature under a nitrogen stream. Was stirred with.

To it, 19.2 g (60 mmol) of 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl (diamine 1) (manufactured by Daikin Industries, Ltd.) was added, and the mixture was heated and stirred at 80 ° C. for 6 hours. Then, the outside temperature was heated to 190 ° C., and the water generated by imidization was azeotropically distilled off together with toluene. After continuing heating, refluxing and stirring for 6 hours, no water was generated. Subsequently, the mixture was heated for 7 hours while distilling off toluene, and after distilling off toluene, methanol was added to reprecipitate, and after the solid content was dried, the solid content was made into an 8% by mass dichloromethane solution to prepare a polyimide solution A containing a polyimide resin A. Prepared. The weight average molecular weight of the polyimide resin A was 140,000.

(Preparation of dope)
A main dope having the following composition was prepared. First, dichloromethane (boiling point 40 ° C.) was added to the pressure dissolution tank. The polyimide solution A prepared above was put into a pressure dissolution tank containing a solvent with stirring. This is heated and completely dissolved while stirring, and this is Azumi Filter Paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare the main dope.

(Composition of main dope)
Dichloromethane 350 parts by mass Polyimide solution A 100 parts by mass Matte agent (Aerosil R812, manufactured by Nippon Aerosil Co., Ltd.) 0.5 parts by mass

(Hypersalivation process)
Then, using an endless belt casting device, the dope was uniformly cast on the stainless belt support at a temperature of 30 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled to 30 ° C.

(Peeling process)
On the stainless belt support, the solvent is evaporated until the amount of residual solvent in the cast film (web) reaches 75%, and then the solvent is peeled off from the stainless belt support at a peeling tension of 180 N / m. did.

(Preliminary drying process)
While transporting the peeled cast film on a roller, it was pre-dried so that the amount of residual solvent was 15% by mass immediately before entering the tenter.

(Stretching process)
The pre-dried cast film was stretched 1.50 times in the width direction using a clip-type tenter while maintaining the temperature from the start of stretching to the end of stretching at 250 ° C. The amount of residual solvent at the start of stretching was 15% by mass.

(Drying process)
While transporting the stretched film with a large number of rollers, the polyimide film [1] was dried at a drying temperature of 120 ° C. with a transport tension of 100 N / m and a drying time of 15 minutes until the residual solvent amount was less than 500 mass ppm. Obtained.

(Preparation of polyimide film [2])
As the polyimide film [2], Neoprim LL-3430 manufactured by Mitsubishi Gas Chemical Company, Inc. was used.

(Preparation of polyimide film [3])
As a reactor, a 1.5 L reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler was filled with 769 g of N, N-dimethylacetamide (DMAc) while passing nitrogen through the reactor, and the reaction was carried out. After adjusting the temperature of the reactor to 25 ° C., 64.046 g (0.2 mol) of 2,2'-bis (trifluoromethyl) benzidine (TFDB) was dissolved to obtain a first solution, and this first solution was used as 25. Maintained at ° C. 8.885 g (0.02 mol) of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanoic acid dianhydride (6FDA) and 3,3,4', 4'-biphenyltetracarboxylic in the first solution After adding 17.653 g (0.06 mol) of acid dianhydride (BPDA) (BPDA), it was stirred for a certain period of time to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, 24.362 g (0.12 mol) of terephthalic acid chloride (TPC) was added to obtain a polyamic acid solution having a solid content concentration of 13 chambers by weight.

13 g of pyridine and 17 g of anhydrous acetic acid were added to the polyamic acid solution and stirred at 25 ° C. for 30 minutes, then further stirred at 70 ° C. for 1 hour to cool to room temperature, and this was precipitated in 20 L of methanol to obtain the precipitated solid content. After filtering and pulverizing, the mixture was dried at 100 ° C. for 6 hours in a vacuum to obtain 108 g of a solid content powder copolymer-polyamide-imide.

The copolymerized polyamide-imide of 108 g of the solid content powder was dissolved in 722 g of N, N-dimethylacetamide (DMAc) to obtain a 13 mass% solution.
The solution thus obtained was applied to a stainless steel plate, cast to a thickness of 390 μm, dried with hot air at 130 ° C. for 30 minutes, and then the film was peeled off from the stainless steel plate and fixed to a frame with a pin. The frame on which the film was fixed was placed in a vacuum oven, slowly heated from 100 ° C. to 300 ° C. for 2 hours, then gradually cooled and separated from the frame to obtain a polyamide-imide film. Then, as a final heat treatment step, the polyamide-imide film was further heat-treated at 300 ° C. for 30 minutes to obtain a polyimide film [3].

(Preparation of polyimide film [4]) In a 500 mL five-necked flask equipped with a thermometer, agitator, a nitrogen introduction tube, a dropping funnel with a side tube, a Dean-Stark apparatus and a cooling tube, under a nitrogen stream, 4,4'as a diamine. 18.515 g (0.050 mol) of −bis (4-aminophenoxy) biphenyl, 2.719 g (0.013 mol) of 3,3′-dihydroxybenzidine as a phenol hydroxyl group-containing diamine, and γ-butyrolactone 42 as an organic solvent. .31 g and 10.58 g of N, N-dimethylacetamide were charged and dissolved. To this, 14.072 g (0.063 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 0.3 g (0.005 mol) of triethylamine as an imidization catalyst were added in a batch by dropping. After completion of the dropping, the temperature was raised to 180 ° C., reflux was performed for 1 hour while distilling off the distillate as needed, and after confirming that the distillate of water was completed, the mixture was cooled to 60 ° C. to obtain a polyimide resin solution. It was. The number average molecular weight of the polyimide resin was 385,000.
After cooling to 60 ° C., 385 g of "DMAC-ST" (average particle size 11 nm, silica content 20% by mass, N, N-dimethylacetamide solution: manufactured by Nissan Chemical Industry Co., Ltd.) was added as silica fine particles, and the mixture was stirred for 2 hours. The mixture was mixed to obtain a polyimide resin composition.
The obtained polyimide resin composition was applied onto a glass plate and held on a hot plate at 100 ° C. for 60 minutes to volatilize an organic solvent to obtain a self-supporting colorless and transparent primary dry film. This film was fixed to a stainless steel frame and heated in a hot air dryer at 250 ° C. for 2 hours to evaporate the organic solvent to obtain a polyimide film [4].

(Preparation of polyimide film [5])
Using SPIXAREA TP001 (Somar) as a polyimide solution, this polyimide solution is mixed with a dispersion in which silica particles having a solid content concentration of 30% by mass are dispersed in γ-butyrolactone, and a dimethylacetamide solution of alkoxysilane having an amino group. , Stirred for 30 minutes.
Here, the mass ratio of the silica particles to the polyimide was 60:40, and the amount of the alkoxysilane having an amino group was 1.67 parts by mass with respect to 100 parts by mass of the total of the silica particles and the polyimide.
The mixed solution was applied to a glass substrate and heated at 50 ° C. for 30 minutes and 140 ° C. for 10 minutes to dry the solvent. Then, the film was peeled off from the glass substrate, a gold frame was attached, and the film was heated at 210 ° C. for 1 hour to obtain a polyimide film [5].

The coefficient of thermal expansion (CTE) of the polyimide films [1] to [5] obtained above was measured by the method described later and is shown in Table I below. Table I also shows the thickness and imide group concentration when the coefficient of thermal expansion of each polyimide film was measured. The polyimide film [1] is a fluorine-based polyimide.

[Example 1]
(Preparation of transparent heat-resistant laminated film [101])
A polyimide film [1] having a thickness of 35 μm is used as the A layer, a polyimide film [3] having a thickness of 5 μm is used as the B layer, and the polyimide film [1] and the polyimide film [3] have a thickness of 5 μm. As described above, an acrylic adhesive was applied and cured to adhere to the polyimide film [3], and a metal layer made of ITO was formed on the polyimide film [3] according to the following method to prepare a transparent heat-resistant laminated film [101].
As a specific method for forming the metal layer made of ITO, a base film made of a polyimide film [1] (A layer) and a polyimide film [3] (B layer) is used, indium oxide is 97% by mass, and tin oxide is 3 A fired body target containing mass% was placed in a sputtering apparatus, and an indium tin oxide layer having a thickness of 27 nm was formed on the polyimide film [3] by a sputtering method.
Next, the base film provided with the indium tin oxide oxide layer was heat-treated at 150 ° C. for 90 minutes to convert the indium tin oxide oxide layer from amorphous to crystalline.

(Preparation of transparent heat-resistant laminated films [102] to [106])
In the preparation of the transparent heat-resistant laminated film [101], the transparent heat resistance is the same except that the type of the polyimide film used for the A layer and the B layer and the layer thicknesses of the A layer and the B layer are changed according to Table II below. Sex laminated films [102] to [106] were produced.

[Example 2]
(Preparation of transparent heat resistant laminated films [201] to [204])
The same applies to the production of the transparent heat-resistant laminated film [101], except that the type of polyimide film used for the A layer and the B layer and the layer thickness of the polyimide film used for the A layer and the B layer are changed according to Table III below. To prepare transparent heat-resistant laminated films [201] to [204], respectively. The ratio of the layer thickness of the A layer and the B layer is shown in Table III below.

[Example 3]
(Preparation of transparent heat-resistant laminated films [301] to [305])
In the production of the transparent heat-resistant laminated film [101], the type of the polyimide film used for the B layer and the layer thickness of the polyimide film used for the A layer and the B layer are changed according to Table IV below, and are used for the A layer. The transparent heat-resistant laminated films [301] to the same, except that the polyimide film [1] was prepared so that the residual solvent amount (drying step) of the polyimide film [1] was the solvent amount shown in Table IV below. [305] was prepared. The ratio of the layer thickness of the A layer and the B layer is shown in Table IV below.

[Example 4]
(Preparation of transparent electrode substrates [401], [402], [405] and [406])
The same applies to the production of the transparent heat-resistant laminated film [101], except that the type of polyimide film used for the A layer and the B layer and the layer thickness of the polyimide film used for the A layer and the B layer are changed according to Table V below. To prepare transparent electrode substrates [401], [402], [405] and [406], respectively.

(Preparation of transparent electrode substrate [403])
In the production of the transparent electrode substrate [402], the transparent electrode substrate [403] was produced in the same manner except that the metal layer formed on the B layer was changed from ITO to a copper mesh.
As a method for forming a metal layer made of a copper mesh, a base film made of a polyimide film [1] (A layer) and a polyimide film [4] (B layer) was glow-discharged and pretreated. The base film after this pretreatment was placed in the vacuum chamber of the magnetron sputtering apparatus facing the copper target, and the degree of vacuum obtained by completely replacing the air with argon was 2.7 × 10 ^-1 Pa (2 ×). In ^{an environment of 10 -3} tolls), sputter vapor deposition was repeated 3 times at an applied voltage of DC 9 kW at 1 m / min, and the thickness of the copper thin film obtained above was 0.6 μm. Then, referring to paragraphs 0046 to 0050 of JP-A-11-243296, a conductive layer of a copper mesh was formed to obtain a transparent electrode substrate [403].

(Manufacturing of transparent electrode substrate [404])
In the production of the transparent electrode substrate [402], the transparent electrode substrate [404] was produced in the same manner except that the metal layer formed on the B layer was changed from ITO to silver nanowires.
Silver nanowires are available from Y. Sun, B. Gates, B.I. Mayers, & Y. Xia, "Crystalline silver nanowires by soft solution processing", Nanolets, (2002), 2 (2) After the method with polyols described in 165-168, in the presence of polyvinylpyrrolidone (PVP). It is a nanowire synthesized by dissolving silver sulfate in 2002 and reducing it. That is, in the present invention, nanowires synthesized by the modified polyol method described in Cambrios Technologies Corporation US Provisional Application No. 60 / 815,627 were used.
As the silver nanowires forming the metal layer, silver nanowire water containing 0.5% w / v of silver nanowires having a minor axis diameter of about 70 to 80 nm and an aspect ratio of 100 or more synthesized by the above method in an aqueous medium. A base composed of a polyimide film [1] (A layer) and a polyimide film [4] (B layer) using a dispersion composition (ClearOhmTM, Inc-AAQ manufactured by Cambrios Technologies Corporation) using a slot die coating machine. It is applied onto the polyimide film [4] of the film so that the thickness becomes 1.5 μm after drying, and after drying ^{, pressure treatment is performed at a pressure of 2000 kN / m 2} to form a metal layer, and a transparent electrode substrate [4] is formed. 404] was obtained.

[Evaluation]
The following items were calculated or evaluated, and the results are shown in Tables I to V.
(Coefficient of thermal expansion)
A test piece of a polyimide film having a thickness of 35 μm composed of a single layer of A layer has a length of 20 mm and a width of 3 mm, and while applying tension to the test piece with a force of 50 mN, the temperature rises from 23 ° C. to 10 ° C./min. The temperature was raised to Tg-50 ° C. of the film, then lowered to 23 ° C., and the temperature was raised again from 23 ° C. to Tg-50 ° C. of the film at a heating rate of 10 ° C./min for the second time. The coefficient of thermal expansion at 50 to 200 ° C. was calculated by the following formula.
<Formula> Coefficient of thermal expansion (ppm / ° C.) = ((Sample length at 200 ° C.)-(Sample length at 50 ° C.) / (Sample length at 23 ° C.)) / (200 ° C.-50 ° C.) ) × 10 ⁶
The polyimide film composed of the B layer single layer was also measured in the same manner as described above.

(Layer thickness)
As for the layer thicknesses of the A layer and the B layer, the thickness of each single layer was measured with a contact type film thickness meter.

(Amount of Remaining Dichloromethane Solvent in Layer A)
The amount of dichloromethane residual solvent contained in the layer A was calculated based on the following formula (Z).
Equation (Z)
Residual solvent amount (%) = (mass before heat treatment of casting film or film (A layer) -mass after heat treatment of casting film or film (A layer)) / (mass after heat treatment of casting film or film (A layer)) Mass after heat treatment) x 100
The heat treatment for measuring the amount of residual solvent means that the heat treatment is performed at 115 ° C. for 1 hour.

(Transparency: Yellow index value)
The yellow index value was determined according to the YI (yellow index: yellowish index) of the film defined in JIS K 7103.
As a method for measuring the yellow index value, a sample of a base film composed of layers A and B is prepared, and using the spectrophotometer U-3300 of Hitachi High-Technologies Corporation and the attached saturation calculation program, etc., JIS The tristimulus values X, Y, and Z of the light source color defined in Z 8701 were obtained, and the yellow index value was obtained according to the definition of the following equation.
Yellow index value (YI value) = 100 (1.28X-1.06Z) / Y

(Durable adhesion)
Each transparent heat-resistant laminated film (or transparent electrode substrate) produced above is composed of a metal layer, an A layer, and a B layer when the following time elapses at 60 ° C. and 90% RH in a state of being bent to 5 mmφ. It was visually confirmed whether the interface with the base film was peeled off. The peeling time was evaluated as follows. ◎, 〇, △ are considered to have no problem in practical use.
⊚: Does not peel off even after 600 hours have passed.
◯: Peeled after 480 hours.
Δ: Peeled after 360 hours.
X: Peeled after 240 hours or before 240 hours.

From the results shown in Tables I to V, the transparent heat-resistant laminated film or transparent electrode substrate of the present invention has better transparency than the transparent heat-resistant laminated film of the comparative example, and has wet and heat durability with the metal layer. It is recognized that the adhesion is good.

[Example 5]
A polyimide film [1] having a thickness of 35 μm is used as the A layer, a polyimide film [3] having a thickness of 5 μm is used as the B layer, and the polyimide film [1] and the polyimide film [3] have a thickness of 5 μm. The acrylic adhesive is applied and cured to adhere to the polyimide film [3], and the average thickness is increased by the DC sputtering method using a sputtering facility composed of a winding machine, a sputtering device, and a winding machine on the polyimide film [3]. A 230 Å 20 mass% Cr chromium-nickel alloy layer was formed as a metal thin film. Further, in the same manner, a copper thin film having an average thickness of 1000 Å was formed on the metal thin film.
Next, a copper layer having a thickness of 9 μm was provided on the copper thin film by an electrolytic copper plating method to obtain a metallized polyimide film. The copper plating bath used was a copper sulfate plating bath having a copper concentration of 23 g / L, and the bath temperature during plating was 27 ° C. Further, the plating tank is a multi-structured tank in which a plurality of plating tanks are connected so that a polyimide film having a metal layer on one side is continuously immersed in each tank by a winding machine and a winding machine. Electroplating was performed while transporting. The transport speed was 75 m / h, and the average cathode current density of the plating tank ^{was adjusted to 1.0 to 2.5 A / dm 2} for copper plating.
Next, using this metal-coated polyimide film, a COF (Chip on film) having a wiring interval of 30 μm and a total wiring width of 15000 μm was produced by a subtractive method. An IC chip was mounted on the IC chip, and the electrodes on the surface of the IC chip and the lead portion of the wiring were wire-bonded at 400 ° C. for 0.5 seconds using a wire bonding device. At this time, the ratio of poor bonding between the lead and the polyimide film generated in the inner lead portion was 0.0001%. The transparent flexible printed circuit board [1] was produced as described above.
When the above-mentioned durability adhesion was evaluated for the produced transparent flexible printed circuit board [1], the polyimide film and the metal thin film did not peel off at the interface.

From the evaluation results shown above, it has been confirmed that the transparent heat-resistant laminated film of the present invention can be suitably used for a transparent flexible printed circuit board, a transparent electrode substrate, an LED lighting device including them, and an organic electroluminescence display device. Was done.

10 Co-current die 11 Mouthpiece 13 Slit 14 Slit 16 Metal support 17 Dope for A layer 18 Dope for B layer 20 Multi-layer structure web 21 A layer 22 B layer

Claims (7)

A transparent heat-resistant laminated film having layers A and B containing a transparent heat-resistant resin and a metal layer in this order.
The A layer contains a fluorinated polyimide resin and contains
The layer B contains a polyimide resin, and the polyimide resin has an imide group concentration in the range of 20 to 30% by mass after imidization of the polyimide precursor.
The B layer has a smaller coefficient of thermal expansion and a thinner layer thickness than the A layer.
The coefficient of thermal expansion of the B layer is in the range of 10 to 40 ppm / ° C.
The yellow index value including the A layer and the B layer is 3.0 or less.
A transparent heat-resistant laminated film in which the A layer and the B layer are bonded by a thermosetting type or photocurable type adhesive. The transparent heat-resistant laminated film according to claim 1, wherein the ratio of the thickness of the A layer to the B layer is within the range of A layer: B layer = 99: 1 to 67:33. The A layer contains dichloromethane and is
The transparent heat-resistant laminated film according to claim 1 or 2, wherein the content of dichloromethane is in the range of 1 to 800 mass ppm. A transparent flexible printed circuit board comprising the transparent heat-resistant laminated film according to any one of claims 1 to 3. A transparent electrode substrate comprising the transparent heat-resistant laminated film according to any one of claims 1 to 3. A lighting device comprising the transparent heat-resistant laminated film according to any one of claims 1 to 3. An organic electroluminescence display device comprising the transparent heat-resistant laminated film according to any one of claims 1 to 3.

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