JP6937557B2 - Method of manufacturing polyimide film - Google Patents

Description

The present invention relates to a method for producing a laminate having a polyimide layer, a method for producing a polyimide film using this laminate, and a method for producing a laminate in which a functional layer is provided on the polyimide layer.

The polyimide film is excellent as a polyimide film for flexible devices. The present invention is suitable as a method for producing an ultrathin polyimide film used for flexible devices such as touch panels, barrier films, liquid crystal displays, organic EL displays, organic EL lighting, electronic paper, color filters, circuit boards, and coverlays.

For example, display devices such as liquid crystal displays and organic EL display devices are used for various display applications such as large displays such as televisions and small displays such as mobile phones, personal computers, and smartphones. Of these, for example, in an organic EL display device, a thin film transistor (TFT) is formed on a glass substrate, electrodes, a light emitting layer, and electrodes are sequentially formed, and finally, the glass substrate or a multilayer thin film is separately airtightly sealed. Is made. The structure of the organic EL device includes a bomb emission structure that extracts light from the glass substrate side that is the supporting base material and a top emission structure that extracts light from the opposite side of the glass substrate that is the supporting base material. It is used properly. Further, since the structure allows external light to pass through as it is, a transparent structure has been proposed in which an electronic element such as a TFT can be seen through from the outside. Both can be realized by selecting transparent electrodes and substrate materials.

By replacing the glass substrate with a resin substrate in these display devices, it is possible to realize thinner, lighter weight, and more flexible display devices than before, and it is possible to further expand the applications and variations of the display devices. However, in general, resin is inferior in dimensional stability, transparency, heat resistance, moisture resistance, gas barrier property, etc. as compared with glass, and various studies have been conducted to improve these.

For example, in Patent Document 1, a base film having a polyimide layer on a support base material is used, a functional layer is formed by a roll-to-roll method or the like, and then the interface between the polyimide layer and the support material is used. It is disclosed that by separating and removing the support material, a laminated member having a functional layer on a thin resin film made of a polyimide layer can be obtained.

Further, Non-Patent Documents 1 and 2 propose an organic EL display device in which a highly transparent resin material is applied to a support substrate.

In Patent Documents 2 and 3, a polyamic acid solution is cast on a support and heated to obtain a partially imidized self-supporting film, which is peeled off from the support, and a stretching device is used. It is described that a polyimide film having been imidized is obtained by heat-treating the film while stretching it in the length direction and the width direction. A tenter having a mechanism for pulling in the width direction is used for this stretching. The tenter is provided with a mechanism for gripping the end portion in the width direction, and has a function of stretching in the width direction by pulling in the width direction while moving a long film or the like in the length direction. This stretching in the width direction is usually performed by gradually widening the width of the gripping mechanism on both end sides as the movement in the length direction is performed.

Japanese Unexamined Patent Publication No. 2014-166722 Japanese Unexamined Patent Publication No. 2013-82149 Japanese Unexamined Patent Publication No. 2004-2880

S. An et. al., “2.8-inch WQVGA Flexible AMOLED Using High Performance Low Temperature Polysilicon TFT on Plastic Substrates”, SID2010 DIGEST, p706 (2010) Oishi et. al., “Transparent PI for flexible display”, IDW’11 FLX2 / FMC4-1

A laminate having a polyimide layer on a support base material improves the handleability of a thin polyimide film, but if the linear expansion coefficient (CTE) of the support base material and the polyimide layer are different, warpage occurs during cooling after curing. It becomes difficult to handle.

The present invention provides a manufacturing method for obtaining a laminate having a thin polyimide layer on a supporting base material, simplifying the drying and heat treatment steps, and suppressing curling even if the CTEs are different combinations. With the goal.

As a result of diligent studies in order to solve the above problems, the present inventors have applied a polyamic acid solution or a polyimide solution on the supporting substrate and cured the supporting substrate while holding both ends, and preferably cured while stretching. The present invention was completed by finding that it is advantageous to make it.

The present invention is a method for producing a laminate having one or more polyimide layers on a support base material, in which a long flexible film is used as the support base material and a polyamic acid is used on the support base material. It has a coating step of applying a solution or a polyimide solution to form one or more coating layers, and a heat treatment step of heat-treating while transporting a supporting base material having the coating layer. The film is conveyed in the feed direction while fixing or pulling the widthwise end of the supporting substrate having the coating layer by the mechanism for gripping the widthwise end, and the heat treatment is imidization of the polyimideic acid. This is a method for producing a laminate having a polyimide layer, which is carried out under the condition that the temperature and time for completion or the maximum temperature is 200 ° C. or higher to form a polyimide layer.

In the method for producing a laminate having a polyimide layer, it is preferable that one or two or more of the following requirements are satisfied.
1) In the heat treatment step, when transporting the supporting base material having the coating layer in the feed direction, transport while pulling in the feed direction.
2) In the coating process, form one or more coating layers on one side or both sides of the supporting base material.
3) The flexible film is a resin film or metal foil with a thickness of 25 to 200 μm.
4) The supporting base material is a polyimide resin film.
5) The difference in the coefficient of thermal expansion between the supporting base material and the polyimide layer is 1 ppm / K or more, or the difference in the coefficient of thermal expansion between the supporting base material and the polyimide layer adjacent to it is 1 ppm / K or more.
6) In the heat treatment step, by pulling the film in the width direction of the supporting base material, the film is stretched so that the stretch ratio in the width direction is 100% to 120%.

It is a preferable aspect of the method for producing a laminate of the present invention that a functional layer forming step is provided next to the heat treatment step and the functional layer is provided on the polyimide layer.

Further, the present invention is characterized in that the laminate obtained by the above-mentioned method for producing a laminate having a polyimide layer is formed into a polyimide film by peeling the polyimide layer at the interface between the support base material layer and the polyimide layer. It is a manufacturing method of.

When the laminate obtained by the above method for producing a laminate having a polyimide layer has a plurality of polyimide layers, the polyimide film layer is peeled off at at least one interface between the polyimide layers to obtain a polyimide film. Is another aspect of the method for producing a polyimide film of the present invention.

According to the method for producing a laminate having a polyimide layer of the present invention, the coating layer and the support base material are not once separated from the support base material having the coated polyimide layer or the precursor layer (coating layer). Since the curing is completed by heat treatment as it is, the manufacturing process is simplified. Further, by heat-treating while applying stretching or tension or holding force in the width direction, not only the CTE of the polyimide layer can be lowered, but also the curl can be reduced even if the CTE of each layer of the laminated body is different. It is possible to prevent the polyimide layer from peeling off during the roll transfer process, and to facilitate the handling of the laminate or the roll.

After the heat treatment step, a functional layer forming step is provided, the functional layer is provided on the polyimide layer, and then the polyimide layer is peeled off at the interface between the supporting base material layer and the polyimide layer to obtain a polyimide film having the functional layer. A flexible device having a functional layer on a thin polyimide film can be effectively obtained.

It is a schematic diagram which shows an example of the apparatus which manufactures the laminated body of this invention. It is a schematic diagram which shows another example of the apparatus which manufactures the laminated body of this invention. It is a top view which shows another example of the apparatus which manufactures the laminated body of this invention.

In the method for producing a laminate having a polyimide layer of the present invention, a coating step of coating a polyamic acid solution or a polyimide solution (hereinafter referred to as a resin solution) on a supporting base material to form one or more coating layers, and coating. It has a heat treatment step of heat-treating while transporting a supporting base material having a layer. Here, the coating layer becomes a polyimide layer after the heat treatment, but since both are resin layers, it is also called a resin layer in the sense that both are included.

A resin solution selected from a polyamic acid solution and a polyimide solution is applied onto the supporting base material. This coating may be on one side or both sides of the supporting substrate. If provided on both sides, two polyimide films can be obtained at the same time. The resin solution may be applied in one layer or in multiple layers, but it is determined according to the use of the polyimide film. If it is applied in multiple layers to form a removable interlayer between the polyimide layers, it is possible to obtain two polyimide films at the same time by peeling there.

The polyamic acid or polyimide in the polyamic acid solution or polyimide solution can be a polyamic acid or polyimide obtained from diamine and tetracarboxylic acid dianhydride and / or tricarboxylic acid anhydride as raw materials. The diamine and the tetracarboxylic dianhydride and / or the tricarboxylic acid anhydride may each consist of a single species or a plurality of species.

Generally, polyimide is obtained by polymerizing an acid anhydride as a raw material and a diamine, and can be represented by the following general formula (1). The polyamic acid is a precursor of polyimide, and can be obtained as polyimide by subjecting it to heat treatment or the like. Therefore, since polyamic acid can be understood from the explanation of polyimide, it is represented by the explanation of polyimide.

式中、Ａｒ_１は酸無水物残基である４価の有機基を表し、Ａｒ_２はジアミン残基である２価の有機基であり、耐熱性の観点から、Ａｒ_１、Ａｒ_２の少なくとも一方は、芳香族残基であるのが望ましい。

In the formula, Ar ₁ represents a tetravalent organic group which is an acid anhydride residue, and Ar ₂ is a divalent organic group which is a diamine residue. From the viewpoint of heat resistance, at least _{Ar 1} and Ar ₂ One is preferably an aromatic residue.

The polyimide used in the present invention is not particularly limited, and as a first example, a polyimide having the following repeating structural unit (a) can be mentioned.

A polyimide having a repeating structural unit (a) as in the first example can form a heat-resistant polyimide layer having a glass transition temperature (Tg) of 300 ° C. or higher, and such a polyimide layer can be formed. By being formed, it is possible to facilitate separation at the interface between the polyimide layer and the support material.

Further, as a second example of the polyimide which is preferably used, a fluorine-containing polyimide can be mentioned. Here, the fluorine-containing polyimide refers to a polyimide having a fluorine atom in the polyimide structure, and has fluorine in at least one component of an acid anhydride and a diamine, which are polyimide raw materials. As such a fluorine-containing polyimide, for example, among those represented by the above general formula (1), Ar _{1 in} the formula is a tetravalent organic group, and Ar ₂ is the following general formula (2) or (3). ) Is represented by a divalent organic group.

_{R 1 to} R ₈ in the general formula (2) or the general formula (3) are hydrogen atoms, fluorine atoms, alkyl groups or alkoxy groups having 1 to 5 carbon atoms, or fluorine-substituted hydrocarbon groups independently of each other. , In the general formula (2), _{at least one of R 1 to} R ₄ is a fluorine atom or a fluorine-substituted hydrocarbon group, and in the general formula (3), R _{1 to} R ₈ At least one of them is a fluorine atom or a fluorine-substituted hydrocarbon group. Of these, suitable specific examples of _{R 1 to} R _{8 include -H, -CH 3} , -OCH ₃ , -F, -CF _{3, and the} like, but at least in the formula (2) or the formula (3). It is preferable that one substituent is _{either -F or -CF 3.}

_{Specific examples of Ar 1} in the general formula (1) in the case of a fluorine-containing polyimide include the following tetravalent acid anhydride residues.

Since the fluorine-containing polyimide as described above includes those having excellent transparency, it is suitable for applications in which a transparent polyimide film is desired. For example, it is suitable as a polyimide layer for obtaining a laminated member that is used in a display device such as a liquid crystal display device or an organic EL display device and requires transparency. Considering that the transparency is made more excellent and the peelability at the interface between the polyimide layer and the support material is further improved, a specific diamine residue giving _{Ar 2 in the general formula (1) is given.} Preferred examples of are shown below.

Further, in such a fluorine-containing polyimide, when any of the structural units represented by the following general formulas (4), (5) or (6) is contained in a proportion of 80 mol% or more, transparency is obtained. In addition to being excellent in peelability, it is more preferable because it has low thermal expansion and excellent dimensional stability. That is, in the case of a polyimide having a structural unit represented by the following general formula (4), (5) or (6), the light transmittance in the wavelength region of 440 nm to 780 nm is 70% or more, preferably 80%. From the above, it is more advantageous to form a polyimide layer in a laminated member that requires transparency such as a display device. Further, the glass transition temperature of 300 ° C. or higher can be obtained, and the coefficient of thermal expansion can be 25 ppm / K or less, preferably 10 ppm / K or less. Therefore, by using such a polyimide, even if the temperature is changed during the process, the thermal expansion coefficients of both are close to each other, so that it is possible to prevent warping or wrinkling. Then, a polyimide resin film is used as the supporting base material, and the polyimide resin film and the polyimide layer formed on the polyimide resin film are both made of such a fluorine-containing polyimide to prevent warping or wrinkling. The effect of

Including the first and second examples above, the polyimide may contain a unit derived from a diamine or acid anhydride having an alicyclic structure, for example, CBDA (1,2,3,4-cyclobutanetetracarboxylic acid). Dianoxide), CHDA (1,2,4,5-cyclohexanedicarboxylic acid anhydride) or trans-1,4-diaminocyclohexane and the like.

Including the first and second examples above, the polyimide can be obtained by imidizing a polyamic acid. Here, the resin solution of polyamic acid is preferably obtained by reacting a diamine as a raw material with tetracarboxylic dianhydride and / or tricarboxylic acid anhydride in substantially equimolar amounts in an organic solvent. .. Specifically, after dissolving diamine in an organic polar solvent such as N, N-dimethylacetamide under a nitrogen stream, tetracarboxylic acid dianhydride and / or tricarboxylic acid anhydride is added, and the temperature at room temperature is about 5 hours. It can be obtained by reacting. From the viewpoint of uniform film thickness during coating and mechanical strength of the obtained polyimide film, the weight average molecular weight of the obtained polyamic acid is preferably 10,000 to 300,000. The preferable molecular weight range of the obtained polyimide layer is also the same molecular weight range as this polyamic acid. Further, the polyimide layer may be formed of a single layer or may be formed of a plurality of layers. When formed from a plurality of layers, it is preferable to use polyimide as described as the first and second examples above, at least for the layer in contact with the supporting base material.

The supporting base material has flexibility and can be coated with a resin solution, and does not peel off until the heat treatment is completed or the subsequent steps such as forming a functional layer are completed. It should be easily peeled off with a force of a certain level or higher. When stretching, a resin film such as a polyimide resin or PET that can be stretched together with the applied resin is suitable. Further, the flexible film referred to in the present invention includes a flexible metal foil such as a copper foil or a SUS foil, and includes a sheet shape. The thickness of the supporting base material is preferably in the range of 20 to 500 μm, preferably in the range of 25 to 200 μm, and more preferably in the range of 50 to 100 μm.

The supporting base material is preferably a polyimide resin film. From the viewpoint of facilitating separation at the interface between the polyimide layer and the supporting base material, the surface of the supporting base material in contact with the polyimide layer preferably has a surface roughness Ra of 100 nm or less, but 30 nm or less. preferable. Further, when stretching, a support base material that is easily stretchable is suitable.

In the production method of the present invention, the coating step and the heat treatment step are often continuously performed, and for that purpose, the supporting base material is continuously fed out by a roll, wound up, and coated while the roll moves. It needs to be long so that it is possible to provide a process and a heat treatment process. The long length is a state in which the other side is longer than one side of the supporting base material, and when forming a roll, the roll is formed so that the long side is in the feeding direction. It should be noted that another step such as a drying step may be provided between the coating step and the heat treatment step, and the drying step and the heat treatment step may be heated in different heating furnaces.

Further, in the production method of the present invention, when the difference in thermal expansion coefficient between the supporting base material and the entire polyimide layer is 1 ppm / K or more, or when the difference in thermal expansion coefficient between the supporting base material and the polyimide layer adjacent to the supporting base material is 1 ppm / K or more. The effect is large when it is 1 ppm / K or more. If the difference in the coefficient of thermal expansion is large, curl is likely to occur, but it can be reduced by the production method of the present invention. In particular, when the coefficient of thermal expansion of the polyimide layer is larger than that of the supporting base material, curl is likely to occur, but according to the production method of the present invention, an increase in the coefficient of thermal expansion of the polyimide layer is suppressed to prevent this. Further, by gripping the end portion of the supporting base material, warpage during the heat treatment process is prevented.

In the coating process, the thickness of the coating layer is not particularly limited, but in order to apply it to applications where transparency is required for the polyimide layer such as a touch panel, a liquid crystal display device, an organic EL display, an organic EL lighting, and a color filter, the polyimide layer is used. Is required to have a transmittance of 80% or more. Therefore, the thickness of the polyimide layer is preferably 30 μm or less, more preferably 20 μm or less, and therefore it is preferable to have such a thickness.

The concentration of the resin solution to be applied is preferably 5 to 30 wt%. As the coating means, a knife coater, a lip coater, a die coater or the like is suitable for the cast coating.

After the coating process is completed, it is dried if necessary and then subjected to a heat treatment process. The drying is carried out by heating at, for example, about 150 to 160 ° C., but a part or all of the drying may be carried out in the heat treatment step. The heat treatment is carried out so that the imidization of the polyamic acid is completed at a temperature at which the maximum temperature is 300 to 450 ° C. The heat treatment performed at the time of imidization may be, for example, continuously or stepwise raising the temperature from a temperature of about 160 ° C. to a temperature of about 400 ° C.

When a polyimide solution is used as the resin solution in the coating step, imidization is not necessary, but drying and heat treatment are necessary, and the maximum temperature is 200 ° C. or higher, preferably 300 ° C. or higher. Perform under conditions. If the heat treatment is performed under conditions such as a temperature and time higher than the drying conditions, the characteristics of the polyimide film are improved.

In this heat treatment step, the film is conveyed in the feeding direction while fixing or pulling the widthwise end of the supporting base material having the coating layer by a mechanism for gripping the widthwise end of the supporting base material. As a result, a polyimide film having a small curl (also referred to as a warp amount) and a CTE can be obtained. A known tenter device can be used as a device for fixing the end portion in the width direction or pulling the end portion in the width direction. Fixing the end in the width direction means applying a holding force or a tensile force to the supporting base material to give the supporting base material a force to keep the tension or the position of the end (for example, the horizontal position) constant without stretching. .. Pulling in the width direction includes stretching in the width direction.
By using the tenter, not only the CTE of the polyimide layer can be reduced, but also the tensile strength of the polyimide film can be increased.

The mechanism and shape for gripping the ends are not particularly limited, and examples thereof include clips for gripping both ends and pins for piercing both ends.

The operation of fixing the end in the width direction or pulling in the width direction may be performed at a temperature of 80 ° C. or higher, preferably 160 ° C. or higher, and after reaching the maximum temperature, the temperature may be within the range until the glass transition temperature of polyimide or lower. preferable. Specifically, the maximum temperature is raised while grasping or pulling the end portion in the width direction of the supporting base material, and after reaching the maximum temperature, the glass transition temperature of the polyimide constituting the polyimide layer to the glass transition temperature minus 100. It is preferable to form the polyimide layer by lowering the temperature to a temperature range of ° C. and relaxing the tensile force in the width direction to 90 to 50% at the time of raising the temperature. By forming the polyimide layer by this method, it is possible to obtain a laminate in which the difference between the CTE in the feed direction and the CTE in the width direction of the polyimide layer is small and the amount of warpage is small.

Stretching in the length direction is possible by adjusting the speeds of the take-up roll and the feed roll and transporting the roll while pulling in the feed direction. Therefore, in the production method of the present invention, it is preferable to stretch the film so as to form a uniaxially stretched or biaxially stretched film. The draw ratio is preferably in the range of more than 1 time and 1.2 times. A polyimide film having a small curl and CTE can be obtained by stretching in the length direction.

The method for producing a laminate having a polyimide layer of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example of an apparatus for manufacturing this laminate. The support base material 4 is pulled out from the roll 8 by the rotating roll 2, and the resin solution is applied to both sides by the two coating apparatus 1. The resin layer 5 is formed. The supporting base material on which the resin layer is formed is dried in a heating furnace 61, heat-treated in a second heating furnace 6 through a plurality of rotary rolls 22 and 23, and then wound up in a take-up roll 3. From the front of the inlet to immediately after the outlet of the heating furnace 6, a tenter having a gripping tool 7 is provided, and both ends of the supporting base material on which the resin layer is formed are held and fixed or stretched.

FIG. 2 shows another example of an apparatus for manufacturing a laminate, and the reference numerals common to those in FIG. 1 have the same meaning. In this example, there is no heating furnace for drying, and drying and heat treatment are performed in the heating furnace 6. FIG. 3 is a plan view of the tenter, and the grips 7 arranged at both ends have a constant distance (opening) between both ends, a portion where the distance between both ends is constant and an enlarged portion which gradually increases. There is a part. Then, the enlarged portion exists in the heating furnace 6 and is stretched there. When not stretched, the supporting base material on which the resin layer is formed is fixed by applying a constant tension, although it does not have an enlarged portion.

The laminate having the polyimide layer obtained through the heat treatment step is peeled off from the supporting base material to form a polyimide film. If the polyimide layer is provided in multiple layers and the polyimide layer can be peeled off, the polyimide layer may be peeled off there as well.

In the present invention, by using the polyimide exemplified above, the adhesive strength at the interface between the polyimide layer and the supporting base material can be preferably 0.1 to 20 N / m, for example, human. It will be possible to easily peel it off by hand. The upper limit of the peel strength when peeling the support base material from the polyimide layer varies depending on the thickness of the polyimide layer, the type of the functional layer, the peeling method, and the like, and is not particularly limited. In order to prevent peeling at the interface between the polyimide layer and the supporting base material when the laminate is conveyed by the roll-to-roll method, it is preferably 0.1 N / m or more. On the other hand, in order to facilitate peeling, it is preferably 20 N / m or less.

Further, when the functional layer is provided on the polyimide film, if the functional layer is provided on the laminated body before peeling, the functional layer can be easily formed even with a thin polyimide film.

Here, the functional layer is a liquid crystal display device, an organic EL display device, an electronic paper, a display device such as a touch panel, a vapor deposition mask, a substrate for a fan-out wafer level package (FOWLP), a lighting device, a detection device, or a component thereof. It constitutes a layer and various functional material layers, and specifically, one kind such as an electrode layer, a light emitting layer, a gas barrier layer, an adhesive layer, an adhesive layer, a thin film transistor, a wiring layer, and a transparent conductive layer. Or it means something like a combination of two or more types.
The polyimide film provided with the functional layer can be used in organic EL lighting equipment, and has various functions such as a conductive film on which ITO and the like are laminated, a gas barrier film that prevents the penetration of moisture and oxygen, and components of a flexible circuit board. It is used as a functional material that has. Preferably, it is used as a flexible device.

A polyimide film provided with a functional layer is called a flexible device, which is an element for an electronic device or a member for an electronic device having flexibility to the extent that it can be bent manually. The form in which the flexible device is mounted on an electronic device may be a bending application in which the curvature changes during use, a fixed curved surface in which the curvature does not change, or a flat surface.

Here, if the laminate having the polyimide layer is warped, it becomes difficult to handle it, and not only the production thereof becomes difficult, but also the lamination of the functional layer and the peeling of the polyimide layer become difficult, so that the curl is small. is important. In order to suppress curl, it is effective to combine the CTEs of the support base material and the polyimide layer, but control by another method is desirable because the selection of the support base material and the polyimide is limited. Therefore, in the heat treatment step, fixing the end portion in the width direction or pulling operation in the width direction is effective for reducing the CTE of the polyimide layer and suppressing curling.

Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not limited to the scope of the following Examples.

The abbreviations in the examples, the methods for measuring various physical properties, and the conditions thereof are shown below.

TFMB: 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl 6FDA: 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride PMDA: dipyromellitic acid Anhydride DMAc: N, N-dimethylacetamide

-Amount of warpage The laminate having the polyimide layer was cut out to a size of 10 cm x 10 cm with the support substrate side facing down and placed on a flat place, and the state of warpage of the laminate was judged. The value of the average value of the floating amount (mm) of the four corners of the laminated body piece was taken as the warp amount. When it was warped on the support substrate side, it was set to a negative (−) value, and when it was warped on the polyimide layer side, it was set to a positive (+) value.

・ Coefficient of thermal expansion: CTE
The polyimide layer is peeled off from the laminate having the polyimide layer to form a polyimide film having a size of 3 mm × 15 mm with the width direction (TD direction) as the long side, and this polyimide film is subjected to 5 by a thermomechanical analysis (TMA) apparatus. A tensile test was conducted in the temperature range of 30 ° C. to 280 ° C. at a constant temperature rise rate (10 ° C./min) while applying a load of 0.0 g, and the coefficient of thermal expansion (ppm /) in the width direction was determined from the amount of elongation of the polyimide film with respect to the temperature. K) was measured. Further, the size was 3 mm × 15 mm with the feeding direction (MD direction) as the long side, and the coefficient of thermal expansion (ppm / K) in the feeding direction was measured by the same measuring method.

Synthesis example 1
849 g of TFMB was dissolved in 7 kg of DMAc in a 30 L reaction kettle. Next, 147 g of 6FDA was added to this solution and stirred, and then 504 g of PMDA was added, 1.5 kg of DMAc was added so that the solid content became 15 wt%, and the mixture was stirred at room temperature for 5 hours to carry out a polymerization reaction. After the reaction, a viscous transparent polyamic acid solution A was obtained.

Synthesis example 2
765 g of TFMB was dissolved in 7 kg of DMAc in a 30 L reaction kettle. Next, 423 g of 6FDA was added to this solution and stirred, and then 311 g of PMDA was added, 1.5 kg of DMAc was added so that the solid content became 15 wt%, and the mixture was stirred at room temperature for 5 hours to carry out a polymerization reaction. After the reaction, a viscous transparent polyamic acid solution B was obtained.

Synthesis example 3
629 g of TFMB was dissolved in 7 kg of DMAc in a 30 L reaction kettle. Next, 871 g of 6FDA was added to this solution and stirred, 1.5 kg of DMAc was added so that the solid content became 15 wt%, and the mixture was stirred at room temperature for 6 hours to carry out a polymerization reaction. After the reaction, a viscous colorless and transparent polyamic acid solution C was obtained.

In the following Examples and Comparative Examples, a polyimide resin film having a thickness of 75 μm and a CTE of 56 ppm / K (520 mm in the width direction and 200 m in the feed direction) was used as the supporting base material. In addition, except for Example 9, the speed of the unwinding roll and the speed of the winding roll were set to 0.5 m / min.

Example 1
The polyamic acid solution A obtained in Synthesis Example 1 was applied onto a long polyimide resin film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, a polyimide layer is formed by heat-treating from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min while holding and fixing the film edge in the width direction of the supporting base material, and a polyimide layer having a thickness of 10 μm is formed. A laminate was obtained.

Example 2
Similar to Example 1, the polyamic acid solution A obtained in Synthesis Example 1 was applied onto a long polyimide resin film as a supporting base material, and then heated and dried at 120 ° C. to remove the solvent. Next, the support base material is carried into the heating furnace while holding the film end in the width direction of the support base material with a gripper, and is supported while being heat-treated at a heating rate of about 30 ° C./min from 180 ° C. to 360 ° C. The substrate was stretched by 2% in the width direction to form a polyimide layer. A laminate having a polyimide layer having a thickness of 10 μm was obtained.

Example 3
The polyamic acid solution B obtained in Synthesis Example 2 was applied onto a long polyimide resin film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, a polyimide layer is formed by heat-treating from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min while holding and fixing the film edge in the width direction of the supporting base material, and a polyimide layer having a thickness of 10 μm is formed. A laminate was obtained.

Example 4
Similar to Example 3, the polyamic acid solution B obtained in Synthesis Example 2 was applied onto a long polyimide resin film as a supporting base material, and then heated and dried at 120 ° C. to remove the solvent. Next, the support base material is carried into the heating furnace while holding the film end in the width direction of the support base material with a gripper, and is supported while being heat-treated at a heating rate of about 30 ° C./min from 180 ° C. to 360 ° C. The substrate was stretched by 2% in the width direction to form a polyimide layer. A laminate having a polyimide layer having a thickness of 10 μm was obtained.

Comparative Example 1
The polyamic acid solution A obtained in Synthesis Example 1 was applied onto a long polyimide resin film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, a polyimide layer was formed by heat-treating from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min without holding the edge of the film, and a laminate having a polyimide layer having a thickness of 10 μm was obtained. ..

Comparative Example 2
The polyamic acid solution B obtained in Synthesis Example 2 was applied onto a long polyimide resin film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, a polyimide layer was formed by heat-treating from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min without holding the edge of the film, and a laminate having a polyimide layer having a thickness of 10 μm was obtained. ..

Example 5
The polyamic acid solution C obtained in Synthesis Example 3 was applied onto a long polyimide resin film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, a polyimide layer is formed by heat-treating from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min while holding and fixing the film edge in the width direction of the supporting base material, and a polyimide layer having a thickness of 10 μm is formed. A laminate was obtained.

Example 6
Similar to Example 5, the polyamic acid solution C obtained in Synthesis Example 3 was applied onto a long polyimide resin film as a supporting base material, and then heated and dried at 120 ° C. to remove the solvent. Next, the support base material is carried into the heating furnace while holding the film end in the width direction of the support base material with a gripper, and is supported while being heat-treated at a heating rate of about 30 ° C./min from 180 ° C. to 360 ° C. The substrate was stretched by 2% in the width direction to form a polyimide layer. A laminate having a polyimide layer having a thickness of 10 μm was obtained.

Example 7
Similar to Example 6, the polyamic acid solution C obtained in Synthesis Example 3 was applied onto a long polyimide resin film as a supporting base material, and then heated and dried at 120 ° C. to remove the solvent. Next, the support base material is carried into the heating furnace while holding the film end in the width direction of the support base material with a gripper, and is supported while being heat-treated at a heating rate of about 30 ° C./min from 180 ° C. to 360 ° C. The substrate was stretched by 5% in the width direction to form a polyimide layer. A laminate having a polyimide layer having a thickness of 10 μm was obtained.

Example 8
Similar to Example 6, the polyamic acid solution C obtained in Synthesis Example 3 was applied onto a long polyimide resin film as a supporting base material, and then heated and dried at 120 ° C. to remove the solvent. Next, the support base material is carried into the heating furnace while holding the film end in the width direction of the support base material with a gripper, and is supported while being heat-treated at a heating rate of about 30 ° C./min from 180 ° C. to 360 ° C. The substrate was stretched by 10% in the width direction to form a polyimide layer. A laminate having a polyimide layer having a thickness of 10 μm was obtained.

Example 9
The polyamic acid solution A obtained in Synthesis Example 1 was applied onto a long polyimide film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, the temperature rise rate of about 30 ° C./min from 180 ° C. to 360 ° C. while stretching in the vertical direction by winding at 0.51 m / min, which is 2% faster than the speed of the unwinding roll (0.5 m / min). A polyimide layer was formed by heat treatment with, and a laminate having a polyimide layer having a thickness of 10 μm was obtained.

Example 10
The polyamic acid solution C obtained in Synthesis Example 3 was applied onto a long polyimide film as a supporting base material, and then dried by heating at 120 ° C. to remove the solvent. Next, both ends in the width direction are gripped, heat treatment is performed from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min while stretching 20%, and then the temperature is lowered to 250 ° C. to stretch in the width direction. A polyimide layer was formed by loosening the above and setting the draw ratio to 16%, and a laminate having a polyimide layer having a thickness of 10 μm was obtained.

Comparative Example 3
After applying the polyamic acid solution C obtained in Synthesis Example 3 on a long polyimide resin film, the solvent was removed by heating and drying at 120 ° C. Next, a polyimide layer was formed by heat-treating from 180 ° C. to 360 ° C. at a heating rate of about 30 ° C./min without holding the edge of the film, and a laminate having a polyimide layer having a thickness of 10 μm was obtained. ..

Tables 1 and 2 show the results of various evaluations of the laminates obtained in Examples and Comparative Examples.

1 Coating device
4 Support base material
6 Heating furnace
7 Grip

Claims (10)

A method for producing a laminate having one or more polyimide layers on a support base material, in which a long flexible film is used as the support base material, and a polyamic acid solution or a polyimide solution is used on the support base material. It has a coating step of forming one or more coating layers by coating, and a heat treatment step of heat-treating while transporting the support base material having the coating layer. By the mechanism for gripping the portion, the support base material is transported in the feed direction while fixing or pulling the width direction end portion of the support base material having the coating layer, and the heat treatment is performed by imidization of the polyimide acid. A method for producing a laminate having a polyimide layer, which is carried out under the condition that the completion temperature and time or the maximum temperature is 200 ° C. or higher to form a removable polyimide layer at an interface with a supporting base material. .. The method for producing a laminate having a polyimide layer according to claim 1, wherein when the supporting base material having the coating layer is conveyed in the feeding direction in the heat treatment step, the supporting base material is conveyed while being pulled in the feeding direction. The method for producing a laminate having a polyimide layer according to claim 1 or 2, wherein in the coating step, one or more coating layers are formed on both sides of the supporting base material. The method for producing a laminate having a polyimide layer according to any one of claims 1 to 3, wherein the flexible film is a resin film or a metal foil having a thickness of 25 to 200 μm. The method for producing a laminate having a polyimide layer according to any one of claims 1 to 4, wherein the supporting base material is a polyimide resin film. A claim characterized in that the difference in thermal expansion coefficient between the support base material and the polyimide layer is 1 ppm / K or more, or the difference in thermal expansion coefficient between the support base material and the polyimide layer adjacent to the support base material is 1 ppm / K or more. The method for producing a laminate having a polyimide layer according to any one of 1 to 5. Claim 1 is characterized in that, in the heat treatment step, by pulling the support base material in the width direction of the support base material, the stretch ratio in the width direction exceeds 1 times and stretches to 1.2 times or less. A method for producing a laminate having a polyimide layer according to any one of 0 to 6.

The method for producing a laminate having a polyimide layer according to any one of claims 1 to 7, wherein a functional layer forming step is provided next to the heat treatment step, and the functional layer is provided on the polyimide layer. The laminate obtained by the method for producing a laminate having a polyimide layer according to any one of claims 1 to 8 is characterized in that the polyimide layer is peeled off at the interface between the support base material layer and the polyimide layer to form a polyimide film. A method for producing a polyimide film. The laminate obtained by the method for producing a laminate having a polyimide layer according to any one of claims 1 to 8 has a plurality of polyimide layers, and a polyimide film is formed at at least one interface between the polyimide layers. A method for producing a polyimide film, which comprises peeling off a layer to form a polyimide film.

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