JP4957592B2 - Polyimide resin composition and molded body thereof - Google Patents

Description

  The present invention relates to a polyimide resin composition and a molded body thereof.

Generally, polyimide resin has high mechanical strength, abrasion resistance, dimensional stability, chemical resistance and other mechanical properties, as well as electrical properties such as insulation properties. Widely used in the electrical and electronic industry.
In recent years, with the advent of an advanced information society, plastic substrates that are lightweight and have excellent flexibility in optical communication fields such as optical fibers and optical waveguides, and optical material fields such as liquid crystal alignment films and protective films for color filters. A glass substrate that can be bent and rolled up is being actively developed. In the field of optical materials, there is a strong demand for the development of resin materials that have excellent folding resistance in addition to transparency and toughness.

  However, in general, a polyimide resin is essentially yellowish brown due to intramolecular conjugation or formation of a charge transfer complex. As a solution to this problem, a method of imparting transparency by using a fluorinated polyimide resin, a semi-alicyclic or a fully alicyclic polyimide resin has been proposed (Patent Documents 1 to 3).

  Although the method using the fluorinated polyimide resin exhibits good transparency, its production cost is high, and it is problematic in that it lacks versatility in industrial use.

  In the method using a semi-alicyclic or fully alicyclic polyimide resin, since the polyimide resin is usually hardly soluble in an organic solvent, it is necessary to use a precursor polyamic acid varnish for molding processing. is there. However, when the polyamic acid varnish is molded, there is a problem that the transparency in the visible light region is remarkably impaired because it is exposed to a high temperature to cause thermal decomposition or the like. Therefore, in applications where transparency is required, there has been an expectation for the development of a solvent-soluble transparent polyimide resin that replaces the polyamic acid varnish.

However, since most conventional solvent-soluble all-alicyclic polyimide resins have relatively low molecular weight, the desired original mechanical properties (particularly toughness) tend to be low.
The reason why the molecular weight is low is that during the imidization reaction during the production of the fully alicyclic polyimide resin, the amic acid produced as an intermediate and the alicyclic diamine form a strong salt, and the reaction hardly proceeds. Is the cause.

  For example, when 1,2,4,5-cyclohexanetetracarboxylic dianhydride is used for the tetracarboxylic acid component, a reported example of obtaining a tough all-cyclocyclic polyimide resin that can be used as a substrate material is There are almost no reports of polyimide resins consisting of 4,4′-diaminodicyclohexylmethane (Patent Document 4).

JP-A-11-106508 JP 2002-146021 A JP 2002-348374 A JP 2005-15629 A

  An object of the present invention is to provide a solvent-soluble polyimide resin and its varnish that can be used for optical material applications, and to provide a polyimide molded body excellent in transparency, flexibility, folding resistance and toughness.

As a result of intensive studies to solve the above-described problems, the present inventors have obtained the following findings (i) to (iii) in the examination process.
(I) 1,2,4,5-cyclohexanetetracarboxylic dianhydride and its derivative are used for the tetracarboxylic acid component, and dicyclohexane skeleton diamine component (A) and polyoxyalkylenediamine component (B) are used for the diamine component. And a polyimide resin excellent in solvent solubility, transparency, flexibility, folding resistance, and toughness.
(Ii) When a part of the diamine component of the dicyclohexane skeleton diamine component (A) and the polyoxyalkylene diamine component (B) of the polyimide resin described in (i) is replaced with a fluorene skeleton diamine component (C), the above physical properties It is possible to increase the refractive index of polyimide resin while maintaining
(Iii) It is possible to reduce the refractive index of the polyimide resin while maintaining the physical properties by dispersing finely divided silica in the polyimide resin described in (i).
The present invention has been completed based on such knowledge and provides the following items.

(Claim 1)
In the presence of a reaction solvent, at least one tetracarboxylic acid component selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and derivatives thereof, and dicyclohexane represented by the following general formula (1) A skeleton diamine component (A), a polyoxyalkylene diamine component (B) represented by the following general formula (2) and a fluorene skeleton diamine component (C) represented by the following general formula (3),
With respect to the tetracarboxylic acid component 100, the component (A) is 20 to 99, the component (B) is 1 to 40, the component (C) is 0 to 40, and the component (A) + A solvent-soluble polyimide resin obtained by imidation polymerization reaction at a charged molar ratio in which the sum of component (B) + component (C) is in the range of 95 to 105.
General formula (1)
[Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents hydrogen, a methyl group, an ethyl group, a methoxy group or an ethoxy group. Y represents a direct bond, —CH ₂ —, —O—, —S—, —SO ₂ —, —CONH—, —C (—CH ₃ ) ₂ — or —CO—. ]
General formula (2)
[Wherein, R ⁵ represents hydrogen or a methyl group. Z represents a linear or branched alkylene group having 2 to 4 carbon atoms. a, b and c each represent an integer of 0 to 50, and the sum of a + b + c is an integer of 2 to 50. ]
General formula (3)
[Wherein R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different and each represents hydrogen, a methyl group or an ethyl group. ]

(Section 2)
In the presence of a reaction solvent, at least one tetracarboxylic acid component selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and derivatives thereof, and dicyclohexane represented by the above general formula (1) A skeleton diamine component (A), a polyoxyalkylene diamine component (B) represented by the general formula (2) and a fluorene skeleton diamine component (C) represented by the general formula (3),
With respect to the tetracarboxylic acid component 100, the component (A) is 20 to 99, the component (B) is 1 to 40, and the component (C) is greater than 0 and less than or equal to 40, and the component (A ) + Solvent-soluble polyimide resin obtained by imidation polymerization reaction at a charged molar ratio of component (B) + component (C) in the range of 95 to 105.

(Section 3)
In the presence of a reaction solvent, at least one tetracarboxylic acid component selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and derivatives thereof, and dicyclohexane represented by the above general formula (1) A skeleton diamine component (A) and a polyoxyalkylene diamine component (B) represented by the general formula (2),
With respect to the tetracarboxylic acid component 100, the component (A) is in the range of 20 to 99 and the component (B) is in the range of 1 to 40, and the total of the component (A) + component (B) is 95 to 105. Solvent-soluble polyimide resin obtained by imidation polymerization reaction at a charged molar ratio in the range of

(Claim 4)
The polyimide varnish containing the polyimide resin in any one of said claim | item 1-3, and the organic solvent.

(Section 5)
Furthermore, the polyimide varnish of said claim | item 4 containing the silica fine particle whose average particle diameter is 0.5-50 nm.

(Claim 6)
Item 6. A polyimide molded body obtained by molding the polyimide varnish according to Item 4 or Item 5.

  According to the present invention, a solvent-soluble polyimide resin and its varnish that can be used for optical material applications, further, a varnish containing silica fine particles in the varnish, and by molding the varnish, transparency, flexibility, A polyimide molded body having excellent folding resistance and toughness can be obtained.

<Solvent-soluble polyimide resin>
The solvent-soluble polyimide resin according to the present invention comprises at least one tetracarboxylic acid component selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and derivatives thereof in the presence of a reaction solvent, The cyclohexane skeleton diamine component (A), the polyoxyalkylene diamine component (B) and the fluorene skeleton diamine component (C) are diamine components with respect to the tetracarboxylic acid component 100, and the components (A) are 20 to 99, respectively. The component (B) is 1 to 40 and the component (C) is in the range of 0 to 40, and the total of the component (A) + component (B) + component (C) is in the range of 95 to 105 It is obtained by carrying out imidization polymerization reaction by dehydration by heating at a molar ratio.

(Tetracarboxylic acid component)
The tetracarboxylic acid component is at least one tetracarboxylic acid selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and derivatives thereof. Examples of 1,2,4,5-cyclohexanetetracarboxylic acid derivatives include 1,2,4,5-cyclohexanetetracarboxylic acid, which is a hydrous acid of the tetracarboxylic dianhydride, , Tri or tetra acid chloride, and mono, di, tri or tetra ester with lower alcohol having 1 to 4 carbon atoms.

  In addition, the tetracarboxylic acid component can be used by substituting a part of the tetracarboxylic acid component with another tetracarboxylic acid component as long as the effects of the present invention are not hindered. Examples of other tetracarboxylic acid components include alicyclic tetracarboxylic acid components, aromatic tetracarboxylic acid components, and aliphatic tetracarboxylic acid components.

Specifically, as the alicyclic tetracarboxylic acid component, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 3 -Carboxymethylcyclopentane-1,2,4-tricarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, Bicyclo [2.2.1] heptanetetracarboxylic dianhydride, bicyclo [2.2.1] heptane-5-carboxymethyl-2,3,6-tricarboxylic dianhydride, bicyclo [2.2.2 ] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, pentacyclo [ .2.1.1 ^4,7. 0 ^2,9 . 0 ^3,8 ] tetradecane-5,6,11,12-tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride Bicyclo [2.2.1] heptane-2-carboxymethyl-2,5,6-tricarboxylic dianhydride, bicyclo [2.2.2] octane-2-carboxyethyl-2,5,6- Examples include tricarboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride and derivatives thereof.

  As the aromatic tetracarboxylic acid component, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4'-oxydiphthalic dianhydride, pyromellitic dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-di Carboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,2 -Screw 2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride Bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 4,4 ′-(p-phenylenedioxy) diphthalic dianhydride, 4 , 4 ′-(m-phenylenedioxy) diphthalic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1 , 2-ethylenebis (anhydrotrimellitate), 1,4-phenylenebis (anhydrotrimellitate), 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo And 3-furanyl) naphtho [1,2-c] furan-1,3-dione and their derivatives are exemplified.

  Examples of the aliphatic tetracarboxylic acid component include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride, and derivatives thereof. The

  Said other tetracarboxylic-acid component can be used for the said imidation polymerization reaction individually or in mixture of 2 or more types.

  When a part of the tetracarboxylic acid component is replaced with the other tetracarboxylic acid component, the amount used is preferably 10 mol% or less, more preferably, based on the number of moles of all tetracarboxylic acid components. 5 mol% or less, particularly 1 mol% or less is recommended.

(Dicyclohexane skeleton component (A))
The dicyclohexane skeleton diamine component (A) represented by the general formula (1), which is a constituent component of the polyimide resin according to the present invention, is not particularly limited, and commercially available products or those obtained by a conventionally known production method can be used. .

Among the dicyclohexane skeleton diamine component (A) represented by the general formula (1), R ¹ , R ² , R ³ and R ⁴ are hydrogen, a methyl group or an ethyl group, and Y is − Those that are CH ₂ —, —O— or —C (—CH ₃ ) ₂ — are recommended.

  Specifically, 4,4′-diaminodicyclohexylmethane, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 3,3′-diethyl-4,4′-diaminodicyclohexylmethane, 3,3 ′ , 5,5′-tetramethyl-4,4′-diaminodicyclohexylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diaminodicyclohexylmethane, 3,5-diethyl-3 ′, 5 ′ -Dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexyl ether, 3,3'-dimethyl-4,4'-diaminodicyclohexyl ether, 3,3'-diethyl-4,4'-diamino Dicyclohexyl ether, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodicyclohexyl ether, 3,3 ', 5,5'-tetraethyl-4,4'-diaminodicyclohexyl ether, 3,5-diethyl-3', 5'-dimethyl-4,4'-diaminodicyclohexyl ether, 2,2-bis (4-amino) (Cyclohexyl) propane, 2,2-bis (3-methyl-4-aminocyclohexyl) propane, 2,2-bis (3-ethyl-4-aminocyclohexyl) propane, 2,2-bis (3,5-dimethyl-) 4-aminocyclohexyl) propane, 2,2-bis (3,5-diethyl-4-aminocyclohexyl) propane, 2,2- (3,5-diethyl-3 ′, 5′-dimethyl-4,4′- Examples include diaminodicyclohexyl) propane. These dicyclohexane skeleton diamine components (A) may be used alone or in admixture of two or more.

  Among the above, preferably 4,4′-diaminodicyclohexylmethane, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-diamino Examples include dicyclohexylmethane, and 4,4′-diaminodicyclohexylmethane is particularly recommended.

(Polyoxyalkylenediamine component (B))
The polyoxyalkylene diamine component (B) represented by the general formula (2), which is a component of the polyimide resin according to the present invention, is not particularly limited, and commercially available products or those obtained by a conventionally known production method can be used. .

Among the polyoxyalkylene diamine components (B) represented by the general formula (2), R ⁵ is hydrogen, a is 2 to 50 and b, c is 0 diamine, R ⁵ is methyl group and a Is a diamine having 2 to 50 and b, c is 0, R ⁵ is a methyl group, Z is an ethylene group, and a + b is 2 to 50 and c is 0, R ⁵ is hydrogen, Z is a tetramethylene group, and a + b is 2 50 and diamines c is 0, ^{R 5} is Z is diamine tetramethylene group and a + b is 2 to 50 and c is 0 in methyl, diamine Z ^{R 5} is hydrogen is a trimethylene group and a + b + c is 2 to 50 , R ⁵ is hydrogen, Z is a tetramethylene group and a + b + c is a diamine of 2 to 50, R ⁵ is a methyl group, Z is an ethylene group, and a + b + c is a diamine of 2 to 50, R ⁵ is a methyl group, and Z is a tetramethylene group And a b + c is recommended diamine of 2 to 50.

More preferably, R ⁵ is hydrogen and a is 5 to 40 and b and c are 0 diamines, R ⁵ is a methyl group and a is 5 to 40 and b and c is 0 diamine, and R ⁵ is methyl. Z is an ethylene group and a + b is a diamine having 5 to 40 and c is 0, R ⁵ is hydrogen, Z is a tetramethylene group and a + b is 5 to 40 and c is a diamine, R ⁵ is a methyl group, and Z is A diamine having a tetramethylene group and a + b of 5 to 40 and c of 0, R ⁵ is hydrogen and Z is a trimethylene group and a + b + c is a diamine of 5 to 40, R ⁵ is hydrogen, Z is a tetramethylene group and a + b + c is 5 to 40 Diamines, R ⁵ is a methyl group, Z is an ethylene group and a + b + c is 5 to 40, and R ⁵ is a methyl group, Z is a tetramethylene group and a + b + c is a diamine having 5 to 40.

More preferably, R ⁵ is hydrogen and a is 10 to 30 and b and c is a diamine of 0, R ⁵ is a methyl group and a is 10 to 30 and b and c is a diamine of 0, and R ⁵ is a methyl group. Z is an ethylene group and a + b is a diamine having 10 to 30 and c is 0, R ⁵ is hydrogen and Z is a tetramethylene group and a + b is 10 to 30 and c is a diamine, R ⁵ is a methyl group and Z is tetramethylene A diamine in which the group and a + b are 10 to 30 and c is 0, R ⁵ is hydrogen, Z is a trimethylene group and a + b + c is a diamine in 10-30, R ⁵ is hydrogen, Z is a tetramethylene group, and a + b + c is a diamine in 10 to 30 A diamine in which R ⁵ is a methyl group, Z is an ethylene group and a + b + c is 10 to 30, and a diamine in which R ⁵ is a methyl group, Z is a tetramethylene group and a + b + c is 10 to 30 is recommended.

  As a commercial item of such a polyoxyalkylene diamine component (B), the Jeffamine series made by Huntsman is exemplified. Specifically, Jeffamine D-230, Jeffamine D-400, Jeffamine D-2000, Jeffamine HK-511 (XTJ-511), Jeffamine XTJ-500 (ED-600), Jeffamine XTJ-501 (ED-900) Jeffamine XTJ-502 (ED-2003), Jeffamine EDR-148 (XTJ-504), Jeffamine XTJ-533, Jeffamine XTJ-536, Jeffamine XTJ-542, and the like. These polyoxyalkylene diamine components (B) can be used alone or in admixture of two or more.

(Fluorene skeleton diamine component (C))
The fluorene skeleton diamine component (C) represented by the general formula (3) that can be a constituent component of the polyimide resin according to the present invention is not particularly limited, and is obtained by a commercially available product or a conventionally known production method. Can be used.

Among the fluorene skeleton diamine components (C) represented by the general formula (3), R ⁶ and R ⁷ are hydrogen, methyl group or ethyl group, and R ⁸ and R ⁹ are hydrogen. Is recommended.

  Specific examples of such a fluorene skeleton diamine component (C) include 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (2-methyl-4-aminophenyl) fluorene, 9,9- Bis (3-methyl-4-aminophenyl) fluorene, 9,9-bis (2-ethyl-4-aminophenyl) fluorene, 9,9-bis (3-ethyl-4-aminophenyl) fluorene, 9,9 -Bis (4-aminophenyl) -1-methylfluorene, 9,9-bis (4-aminophenyl) -2-methylfluorene, 9,9-bis (4-aminophenyl) -3-methylfluorene, 9, Examples include 9-bis (4-aminophenyl) -4-methylfluorene. These fluorene skeleton diamine components (C) may be used alone or in combination of two or more.

  Among the above, 9,9-bis (4-aminophenyl) fluorene and 9,9-bis (3-methyl-4-aminophenyl) fluorene are recommended.

  The charged molar ratio of the dicyclohexane skeleton component (A) is 20 to 99 with respect to the tetracarboxylic acid component 100, and it is recommended to use it in a molar ratio range of 30 to 97.

  The charged molar ratio of the polyoxyalkylene diamine component (B) is 1 to 40 with respect to the tetracarboxylic acid component 100, and it is recommended that the polyoxyalkylene diamine component (B) be used in a molar ratio range of 3 to 30.

  Moreover, when a fluorene frame | skeleton diamine component (C) is used, it is possible to raise the refractive index of the polyimide molded body obtained. However, as a harmful effect of using the fluorene skeleton diamine component (C), there is a tendency that the transparency of the obtained polyimide molded body is impaired.

  Therefore, the charged molar ratio of the fluorene skeleton diamine component (C) is 0 to 40 (0 or greater than 0 and 40 or less), preferably 0 to 35 (greater than 0 or 0) with respect to the tetracarboxylic acid component 100. It is recommended to use in a molar ratio range of 35 or less).

  The charge molar ratio of each component according to the present invention is such that the total of the diamine component (A), the diamine component (B), and the diamine component (C) is in the range of 95 to 105 with respect to the tetracarboxylic acid component 100. Yes, preferably in the range 98-102. By performing the imidization polymerization reaction within this range, a polyimide resin having a sufficient degree of polymerization that can be used for optical material applications can be obtained.

  Other diamine components can be used in combination with the diamine component as long as the effects of the present invention are not hindered. Other diamine components include aromatic diamine components, alicyclic diamine components, and aliphatic diamine components.

Examples of the aromatic diamine component include diamines having 6 to 30 carbon atoms having at least one aromatic ring in the molecule.
Specifically, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4,4′-diaminobiphenyl, 4,4′-diaminodiphenylmethane, 1, 1-bis (4-aminophenyl) ethane, 1,2-bis (4-aminophenyl) ethane, 2,2-bis (4-aminophenyl) propane, bis (4-aminophenyl) sulfide, bis (4- Aminophenyl) sulfoxide, bis (4-aminophenyl) sulfone, 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 1,3- Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) ben 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, bis [4- (4-amino Phenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [3- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2- Bis [3- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) -3-methylphenyl] propane, 4,4′-bis (4-aminophenoxy) Phenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) -3,3′-methylbiphenyl, bis [4- (4-aminophenoxy) phenyl] sulfide Bis [3- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [3- (4-aminophenoxy) phenyl] sulfoxide, bis [4- (4- Aminophenoxy) phenyl] sulfone, bis [3- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (4-Aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy) phenyl] Tons and the like are exemplified.

Examples of alicyclic and aliphatic diamine components include 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 1,3 -Bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, 2,3-diaminobicyclo [2.2.1] heptane, 2,5-diaminobicyclo [2.2.1] heptane, 2,6-diamino Bicyclo [2.2.1] heptane, 2,7-diaminobicyclo [2.2.1] heptane, 2,5-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,6-bis (Aminomethyl) -bicyclo [2.2.1] heptane, 2,3-bis (aminomethyl) -bicyclo [2.2.1] heptane, 3 (4), 8 (9) -bis Aminomethyl) - tricyclo [5.2.1.0 ^2. 6] Decane, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-hebutanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1 , 9-nonanediamine, 1,10-decanediamine, alkylene diamine such as 1,12-dodecanediamine, oxydi (2-aminoethane), oxydi (2-aminopropane), 1,4-bisaminopropylpiperazine, etc. The These other diamine components can be used alone or in combination of two or more for the imidation polymerization reaction.

  When the other diamine component is used, the amount used is preferably 10 mol with respect to the total number of moles of the diamine component (A), the diamine component (B) and the diamine component (C). % Or less, more preferably 5 mol% or less, particularly 1 mol% or less is recommended.

  In the present specification and claims, each diamine component is described in the form of “diamine”. However, for the purpose of improving the reactivity and exhibiting the effects of the present invention, amino groups are substituted for them. A compound in which a part or all of it is converted to an isocyanate group, a silylated compound, or the like can be used.

<Reaction solvent>
The reaction solvent used in the imidation polymerization reaction according to the present invention may be any reaction solvent as long as it does not inhibit the imidation polymerization reaction and can dissolve the polyimide resin to be formed. For example, preferred examples include aprotic solvents, phenol solvents, ether solvents, carbonate solvents, and the like.

  Specific examples of the aprotic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea and the like. Amide solvents, lactone solvents such as γ-butyrolactone, γ-valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoric amide, hexamethylphosphine triamide, sulfur-containing dimethylsulfone, dimethylsulfoxide, sulfolane, etc. Examples thereof include ketone solvents such as acetone solvents, acetone, cyclohexane and methylcyclohexane, amine solvents such as picoline and pyridine, and ester solvents such as acetic acid (2-methoxy-1-methylethyl).

  Specific examples of the phenol solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4 -Xylenol, 3,5-xylenol and the like are exemplified.

  Specific examples of the ether solvent include 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl]. Examples include ether, tetrahydrofuran, 1,4-dioxane and the like.

  Specific examples of carbonate solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, and the like. You may use said reaction solvent individually or in mixture of 2 or more types.

  Among these reaction solvents, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N, N-dimethylformamide, and N, N-dimethylacetamide are particularly recommended.

  The amount of the reaction solvent used may be an amount that can dissolve the produced polyimide resin. It is recommended that the specific polyimide resin concentration be adjusted to preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and still more preferably 10 to 30% by weight. The density | concentration of a polyimide resin can be calculated | required by measuring the amount of weight reduction before and behind a heating using a TG-DTA apparatus (differential thermothermal weight simultaneous measuring apparatus) like the below-mentioned Example.

  The reaction solvent may be the same as or different from the organic solvent constituting the polyimide varnish according to the present invention, but is preferably the same in consideration of the complexity of the solvent replacement operation.

<Imidation polymerization reaction>
The reaction method of the imidation polymerization reaction is not particularly limited as long as the target polyimide resin can be produced, and a known reaction method can be used.

  As a specific reaction method, (i) a predetermined amount of all components (reaction substrate) and a reaction solvent are charged into a reactor, stirred at room temperature to 80 ° C. for 0.5 to 30 hours, and then subjected to imidation polymerization reaction. A method of performing an imidation polymerization reaction at a reaction temperature; (ii) a predetermined amount of all diamine components and a reaction solvent are charged and dissolved in a reactor, and then a predetermined amount of tetracarboxylic acid component is charged at room temperature to 80 ° C. A method of performing an imidation polymerization reaction at the reaction temperature of the imidation polymerization reaction after stirring for 0.5 to 30 hours, (iii) A predetermined amount of a dicyclohexane skeleton diamine component (A) and a reaction solvent are charged into a reactor and dissolved. Then, a predetermined amount of a tetracarboxylic acid component is charged and stirred at room temperature to 80 ° C. for 0.5 to 30 hours, and then a predetermined amount of polyoxyalkylenediamine component (B) and fluorene skeleton diamine component (C) are added. And (iv) carrying out the imidation polymerization reaction at the reaction temperature of the imidation polymerization reaction, (iv) charging a predetermined amount of the dicyclohexane skeleton component (A) and the reaction solvent into the reactor, and then dissolving the predetermined amount of tetra After the carboxylic acid component is charged and stirred at room temperature to 80 ° C. for 0.5 to 30 hours, the imidation polymerization reaction is performed at the reaction temperature of the imidization polymerization reaction, and a predetermined amount of polyoxyalkylenediamine component (B) and fluorene skeleton A method in which the diamine component (C) is charged and the imidization polymerization reaction is further performed at the reaction temperature of the imidation polymerization reaction. (V) All the reaction substrates and reaction solvents in a predetermined amount are charged into the reactor, and the imidization polymerization reaction is immediately performed. Examples thereof include a method in which the temperature is raised to a reaction temperature and an imidation polymerization reaction is performed.

  The reaction temperature of the imidation polymerization reaction is usually 120 to 250 ° C, preferably 160 to 190 ° C. When reaction temperature is lower than 120 degreeC, the tendency for an imidation ratio to become low is recognized. When the reaction temperature is higher than 250 ° C., a thermally crosslinked body may be partially formed to cause thickening or generation of a gel-like material. Moreover, since decomposition of the solvent proceeds and yellowing occurs, it is not preferable.

  Although the reaction time of the imidation polymerization reaction depends on the type of substrate, the charging ratio, the substrate concentration, and the like, it is usually preferably about 2 to 10 hours after the start of the distillation of the produced water. When reaction time is too short, the tendency for imidation ratio to become low is recognized. If the reaction time is too long, the reaction system may partially cause a thermal crosslinking reaction to thicken the reaction system or form a gel-like material, or the reaction system may be colored due to thermal degradation of the reaction solvent. .

In the imidation polymerization reaction, it is preferable to perform the reaction using a Dean Stark apparatus or the like while removing water generated during production. By performing such an operation, the degree of polymerization and the imidization rate can be further increased. At this time, it is recommended to use a liquid or a gas body accompanied with water for the purpose of efficiently removing generated water. The accompanying liquid or gas body is generally called a reflux liquid, an azeotropic agent, an accompanying agent or an accompanying gas.
Examples of the reflux liquid include benzene, toluene, xylene, ethylbenzene, tetralin, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, and mixtures thereof. These reflux solutions are usually used in an amount of 5 to 25% by weight based on the reaction solvent. The addition time is not particularly limited, and may be added to the reaction system from the time when the reaction solvent is charged, or may be added immediately before the imidation polymerization reaction.

  The inside of the reaction system is desirably an inert gas atmosphere from the viewpoint of preventing coloration and safety of the reaction system. Usually, a method is used in which the inside of the reaction system is replaced with an inert gas and the inert gas is circulated during the reaction. Examples of the inert gas include nitrogen and argon.

  In the imidation polymerization reaction according to the present invention, a known catalyst can be used. However, it is preferable to carry out the reaction in the absence of a catalyst from the viewpoints of complicated post-treatment, deterioration of the storage stability of the polyimide varnish due to the residual amount of catalyst used, and coloring of the polyimide varnish.

  When a catalyst is used, for example, pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, trimethylamine, Organic base catalysts such as butylamine, imidazole, N, N-dimethylaniline, N, N-diethylaniline, inorganic bases represented by potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate Examples are catalysts.

  Examples of the acid catalyst include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and the like. Is exemplified.

  The imidation rate in the imidation polymerization reaction is preferably 100%, but the imidization rate effective from an industrial viewpoint is usually 70% or more, preferably 75% or more, more preferably 80% or more, particularly 85% or more is recommended. This is because the operation of bringing the imidization rate close to 100% not only causes the reaction time of the imidation polymerization reaction to exceed (that is, the productivity decreases), but also increases the reaction system due to the excess of the reaction time. May promote by-product of viscosity and gel. When the imidization ratio is less than 70%, the long-term storage stability of the polyimide varnish is impaired, and the cause of surface defects and voids accompanying the evaporation of the generated water during the molding process, particularly the molded body Since it may cause a decrease in transparency, it is not preferable.

  The number average molecular weight of the present polyimide resin obtained by the imidation polymerization reaction is usually 8,000 to 100,000, and the polydispersity is usually in the range of 1.5 to 20.0. This range is a range having a degree of polymerization that can give a molded product.

  In addition, as long as the effects of the present invention are not impaired, known monofunctional acid anhydrides and monoamines used in this field are used in combination as end cap agents for the purpose of improving heat resistance, adhesion, and molecular weight control. can do. Specific examples of the end cap agent include phthalic anhydride, maleic anhydride, nadic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. for acid anhydrides, and aniline, methylaniline, allylamine, etc. for monoamines. The

<Polyimide varnish>
The polyimide varnish of the present invention contains the present polyimide resin and an organic solvent.

  As a method for preparing a polyimide varnish, (i) a method of using a reaction solvent solution of a polyimide resin obtained by an imidization polymerization reaction as it is as a polyimide varnish, (ii) a reaction solvent solution of a polyimide resin obtained by an imidization polymerization reaction Examples are a method of obtaining a polyimide varnish by isolating a polyimide resin from the following and then dissolving the isolated polyimide resin in a desired organic solvent.

  The solution viscosity of the polyimide varnish is recommended to be in the range of 0.5 to 50 Pa · s, preferably 1.0 to 20 Pa · s (measurement conditions; B-type viscometer, resin concentration 20 wt%, 25 ° C.). The It is desirable that the viscosity is appropriately adjusted during the production of the varnish.

  The concentration of the polyimide resin in the polyimide varnish is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and further preferably 10 to 30% by weight. The density | concentration of a polyimide resin can be calculated | required by measuring the amount of weight reduction before and behind a heating using a TG-DTA apparatus (differential thermothermal weight simultaneous measuring apparatus) like the below-mentioned Example.

  The organic solvent is not particularly limited as long as it is an organic solvent capable of dissolving the polyimide resin according to the present invention, and specific examples include those exemplified as the reaction solvent. Of these, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N, N-dimethylformamide, and N, N-dimethylacetamide are particularly recommended.

  Moreover, you may add another component, as long as the effect of this invention is acquired. Examples include polyester resins, polyimide resins (excluding the polyimide resin of the present invention), polymer compounds such as polyamideimide resins and polyamide resins, flame retardants, antifoaming agents, and antioxidants.

  As the antioxidant, a conventionally known antioxidant can be used without particular limitation. Examples of such antioxidants include phenol-based antioxidants, amine-based antioxidants, benzotriazole-based antioxidants, etc. Among them, phenol antioxidants are preferable, and in particular, the number of carbon atoms is 6 to 100, more preferably carbon number. The phenolic antioxidant of 10-80 is preferable at the point which gives the outstanding heat resistance (retention rate of the elasticity modulus after a long-term heating) to a polyimide copolymer. Specific examples of such phenolic compounds include 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 4,4′-methylenebis (2,6-di-tert). -Butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl- 6-tert-butylphenol), 4,4′-isopropylidenebisphenol, 2,4-dimethyl-6-tert-butylphenol, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,2′-dihydroxy-3,3-di (Α-methylcyclohexyl) -5,5′-dimethyldiphenylmethane, 2,2′-isobutylidenebis (4,6-dimethylphenol), 2,6-bis (2′-hydroxy-3′-tert-butyl) -5′-methylbenzyl) -4-methylphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,5-di-tert-amylhydroquinone, 2,5-di-tert-butylhydroquinone, 1, 4-dihydroxyanthraquinone, 3-tert-butyl-4-hydroxyanisole, 2-tert-butyl-4-hydroxyanisole, 2 , 4-Dibenzoylresorcinol, 4-tert-butylcacatechol, 2,6-di-tert-butyl-4-ethylphenol, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′ -Dihydroxy-4-methoxybenzophenone, 2,4,5-trihydroxybenzophenone, α-tocopherol, bis [2- (2-hydroxy-5-methyl-3-tert-butylbenzyl) -4-methyl-6-tert -Butylphenyl] terephthalate, triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di- tert-butyl 4-hydroxyphenyl) propionate] It is. Among these, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4, 4′-isopropylidenebisphenol, 2,4-dimethyl-6-tert-butylphenol, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3 -Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3, -Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,6-di-tert-butylphenol, bis [2- (2-hydroxy-5-methyl) -3-tert-butylbenzyl) -4-methyl-6-tert-butylphenyl] terephthalate, triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1, Examples include 6-hexanediol-bis [3- (3,5-di-tert-butyl 4-hydroxyphenyl) propionate] and the like.

  The polyimide varnish containing silica fine particles according to the present invention is a varnish characterized by containing silica fine particles having an average particle size of 0.5 to 50 nm in the polyimide varnish.

The silica used for the above-mentioned silica fine particles is silicon dioxide (SiO ₂ ), and the form (crystal form, amorphous form, etc.) is not limited.

  The shape of the silica fine particles is not particularly limited, and examples thereof include a spherical shape, an elliptical shape, a flat shape, a rod shape, and a fiber shape.

  The silica fine particles contained preferably have a small particle size in order to prevent light scattering and to maintain high light transmittance. The average particle size is 0.5 to 50 nm, preferably 0.5 to 30 nm. The average particle diameter is a value measured using the BET method described in Examples described later.

  The content of silica is preferably 1 to 50% by weight, more preferably 10 to 40% by weight, based on the polyimide resin. As the content increases, the refractive index of the resulting polyimide molded body decreases. However, when the content is large, there is a tendency for flexibility and folding resistance to decrease.

  Various known methods can be used as a method for incorporating the silica fine particles into the polyimide varnish. For example, there can be mentioned a method of adding silica silane or polyalkoxy silane to a polyimide varnish, adding a small amount of hydrolysis accelerator such as water, and dispersing silica fine particles by a sol-gel method. Moreover, the fine particle silica powder manufactured by the vapor phase method as colloidal silica is also marketed, and you may add and mix directly to a varnish.

  As a suitable example for preparing the silica fine particle-containing polyimide varnish according to the present invention, a method of preparing an organosilica sol mixed with a polyimide varnish is recommended.

  The organosilica sol is obtained by dispersing silica fine particles in an organic solvent at a ratio of about 20% by weight. Examples of the organic solvent include methanol, isopropanol, normal butanol, ethylene glycol, normal propyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, and propylene. Those using glycol monomethyl acetate, propylene glycol monomethyl ether, xylene, N, N-dimethylacetamide or the like are commercially available.

  The organic solvent of the organosilica sol is preferably a good solvent for polyimide, and N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide are particularly recommended. Is done.

  In order to improve the dispersibility of silica with respect to the polyimide resin, it is preferable to treat the organosilica sol with a silane coupling agent. If the terminal functional group of the silane coupling agent has an epoxy group or amino group, it will bind to the carboxylic acid remaining in the polyimide resin, increasing the affinity between the silica sol and the polyimide resin, resulting in more effective dispersion. It can be performed.

  Examples of such silane coupling agents include those having an epoxy group such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidyloxypropyl (dimethoxy) methylsilane, and 3-glycidyloxy. Examples include propyltrimethoxysilane and diethoxy (3-glycidyloxypropyl) methylsilane.

  Moreover, as a silane coupling agent having an amino group, 3- (2-aminoethylamino) propyldimethoxymethylsilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propyl Triethoxysilane, 3- (3-aminopropylamino) propyltriethoxysilane, 3- (3-aminopropylamino) propyltrimethoxysilane, 3-aminopropyldiethoxymethylsilane, 3-aminopropyltriethoxysilane, 3 -Aminopropyltrimethoxylane and the like are exemplified.

  Various known methods can be used as a method of treating the organosilica sol with a silane coupling agent. For example, it can be treated by adding a silane coupling agent to organosilica sol with adjusted silica concentration and stirring at room temperature to 80 ° C. for 0.5 to 2 hours. At this time, a small amount of water may be added to accelerate the treatment reaction.

<Preparation method of silica fine particle-containing polyimide varnish>
A preferred method for preparing the silica fine particle-containing polyimide varnish according to the present invention will be described below.

A polyimide varnish is dropped at room temperature to 40 ° C. in a commercially available organosilica sol or an organosilica sol treated with a silane coupling agent by the method described above. The dropping speed depends on the amount of the organosilica sol and the silica concentration in the organosilica sol, but all of the polyimide varnish is dropped in the range of 10 minutes to 3 hours.
It is recommended that the silica concentration of the organosilica sol before dropping is 5 to 50% by weight, preferably 10 to 20% by weight. Further, the resin concentration of the dropped polyimide varnish is desirably a dilute within a range that does not impair the practicality, so that the dispersibility is improved. The range is recommended to be 1 to 40% by weight, preferably 5 to 30% by weight. .
Preparation is completed by continuing stirring in the temperature range of room temperature to 80 ° C. for 0.5 to 2 hours after dropping of the polyimide varnish.

<Polyimide molded product>
The polyimide molded body of the present invention is obtained by molding the polyimide varnish. As a method for molding, a conventionally known method can be used without any particular limitation.
For example, after applying or molding the polyimide varnish into a film, film, fiber, or sheet, the organic solvent is removed from the polyimide varnish to form a film, film, fiber, or sheet of polyimide. Examples are a method of forming into a body.

  As an example of producing a polyimide molded body, a polyimide varnish is cast on a PET substrate (polyethylene terephthalate substrate), and is placed in a vacuum dryer (decompression degree: 1 to 10 mmHg) at room temperature for 30 minutes to 2 hours, and further about 200. The temperature is raised to 30 ° C. in 30 minutes to 2 hours, and the solvent is distilled off at that temperature for 1 to 4 hours. After cooling to room temperature, the polyimide film formed on the PET substrate is taken out from the vacuum dryer and peeled off from the PET substrate. Fix the peeled polyimide film to a stainless steel metal frame, and again raise the temperature from room temperature to 230 to 280 ° C. in 1 to 4 hours in a vacuum dryer, and dry at that temperature for 2 to 5 hours to completely remove the solvent. After distilling off and cooling to room temperature, a polyimide film can be obtained by taking out from the vacuum dryer. A method of adjusting the thickness of the polyimide film thus obtained to a target thickness by adjusting the coating thickness at the time of casting can be mentioned.

  The transparency of the polyimide molded body can be evaluated by, for example, the total light transmittance (film thickness: 80 μm) and yellowness. The total light transmittance (film thickness: 80 μm) is usually 85% or more, preferably 90% or more. The total light transmittance is a value obtained by the method described in Examples described later in this specification and claims.

  The yellowness is usually 7.0 or less, preferably 5.0 or less, more preferably 3.0 or less. The yellowness is a value obtained by the method described in Examples described later in the present specification and claims. The range of the total light transmittance and the yellowness is an effective range particularly in applications that place importance on transparency such as optical material applications.

  The flexibility and folding resistance of the polyimide molded body can be evaluated by, for example, values obtained by a flexibility test described in Examples described later. The evaluation value for the flexibility test is preferably 20 or more, more preferably 30 or more, and still more preferably 40 or more. The flexibility test is a value obtained by the method described in Examples described later in this specification and claims. This range is an effective range particularly in applications that require flexibility and folding resistance.

  The toughness of the polyimide molded body can be evaluated by, for example, breaking elongation by a tensile test. The elongation at break is preferably 50% or more, more preferably 80% or more, and still more preferably 100% or more. The elongation at break is a value obtained by the method described in Examples described later in the present specification and claims. This range is an effective range particularly for applications that require high toughness.

  Moreover, the refractive index of a polyimide resin can obtain the molded object of a high refractive index by adjusting the ratio of the fluorene frame | skeleton diamine component which is a copolymerization component of a polyimide resin, and adjusts content of a silica fine particle. Thus, a molded article having a low refractive index can be obtained. By using these polyimide resins, the refractive index of the polyimide molded body can be adjusted in the range of usually 1.480 to 1.590.

  Since the polyimide molded body of the present invention thus obtained has transparency, flexibility, folding resistance, and high toughness, it can be suitably used as an optical material application. Examples include applications such as liquid crystal display applications, organic electroluminescence display applications, solar cell applications, and polymer optical waveguides.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, the analytical value in each Example and a comparative example was calculated | required with the following method.

[Average particle diameter of silica fine particles]
<BET method>
In accordance with JIS Z8830 (2001), a specific surface area S (m ² / g) was measured using Tristar 3000 manufactured by Shimadzu Corporation.
The average particle diameter D (nm) of the silica fine particles was obtained from the calculation formula D = 6000 / S × ρ (density). The density of silica was 2.2 g / cm ³ .

<Number average molecular weight of polyimide resin>
The number average molecular weight of the polyimide resin was determined by GPC (gel permeation chromatograph).
As the GPC apparatus, LC-20A (manufactured by Shimadzu Corporation) was used. As the separation column, Showa Denko “AD-802.5 / S”, “AD-803 / S”, “AD-804 / S” and “AD-805 / S” were connected in that order. As the eluent, N, N-dimethylformamide (3.8 L) to which lithium bromide (1.7 g) and phosphoric acid (1.9 g) were added was used. The molecular weight was determined as a converted molecular weight using polyethylene glycol as a standard substance.

<Concentration of polyimide resin in reaction solution>
The concentration (% by weight) of the polyimide resin in the reaction solution was determined according to the following method.
10 mg of the polyimide resin reaction solution is precisely weighed (to the second decimal place) and set in a TG-DTA device (device name manufactured by Seiko Instruments Inc .; EXSTAR6000, TG-DTA6200). The weight at 0 ° C. was measured. It calculated according to the following formula (1) using the obtained measured value.
Measurement condition;
Temperature increase rate: 5 ° C / min Flowing nitrogen amount: 100ml / min Measurement start temperature: 30 ° C
(a formula)
Concentration of polyimide resin in reaction solution = (W1 / W0) × 100 (1)
W1; Weight of measurement sample at 350 ° C. (g)
W0: Weight of measurement sample before starting measurement (g)
In addition, the resin concentration of a polyimide varnish can also be calculated | required with the same measuring method.

[Evaluation of physical properties of polyimide moldings]
<Total light transmittance>
The total light transmittance (%) of the polyimide molded body (film, thickness 80 μm) according to the present invention is determined according to JIS K-7361-1 (1996) using a haze meter HAZE GARD II (manufactured by Toyo Seiki Co., Ltd.). Measured.

<Yellowness (Yellow Index)>
The yellowness of the polyimide molded body (film, thickness 80 μm) according to the present invention was measured according to JIS K7105 (1981) using a colorimeter CM-3500d (manufactured by Minolta) and using a light source C.

<Flexibility test>
In the flexibility test, a sample of 30 mm × 30 mm size was cut out from a polyimide molded body (film) having a thickness of 50 μm, bent into a 30 mm × 15 mm rectangle with overlapping corners and corners, and the bent portion was pointed to Then, the sample was opened and bent to the opposite side, and the same operation was repeated in the same manner, and the number of breaks of the sample crease was recorded. A similar test was performed on 10 samples, and the average value (rounded to one decimal place) was used as the evaluation value for the flexibility test.

<Tension modulus, elongation at break>
The tensile modulus, tensile strength, and elongation at break of the polyimide molded body (film) were measured according to JISK7127 (1999) using a universal material testing machine 5565 (Instron). First, a test piece having a thickness of 80 μm and a width of 10 mm was fixed to a length of 50 mm, and the test piece was stretched at a speed of 10 mm / min under the conditions of 25 ° C. and RH 60%.

<Refractive index>
The refractive index was measured at 25 ° C. by D line (589 nm) using a Milton Roy Abbe refractometer according to JIS K7142 (1996). As the immersion liquid, 1-bromonaphthalene was used.

Abbreviations used in the following examples are as follows.
HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride HDAM: 4,4′-diaminodicyclohexylmethane XTJ-542: In the above general formula (2), R ⁵ is a methyl group, a + c = 6, b = 9 diamine ("Jeffamine XTJ-542" manufactured by Huntsman)
Total amine number (mgKOH / g) 109.8 (established by Japan Oil Chemistry Association "Standard Oil Analysis Test Method")
FDA: 9,9-bis (4-aminophenyl) fluorene DMI: 1,3-dimethylimidazolidinone NMP: N-methyl-2-pyrrolidone DMAC-ST: average particle size 15 nm, silica 20 wt%, N, N- Dimethylacetamide solution (“DMAC-ST” manufactured by Nissan Chemical Industries, Ltd.)
KBM-403: 3-glycidyloxypropyltrimethoxysilane (“KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.)

Example 1
After substituting the inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen introducing tube, a separator decanter and a cooling tube with nitrogen, 60.0 g HDAM as a dicyclohexane skeleton diamine component (A) under a nitrogen stream 0.285 mol), 1,215 g of DMI as a reaction solvent and 151 g of ethylcyclohexane as a refluxing solution were stirred for 15 minutes at room temperature to dissolve the diamine. Next, 75.2 g (0.335 mol) of powdered HPMDA as a tetracarboxylic acid component was added with stirring. After a while, salt was formed and an exotherm was observed. After confirming that the exotherm had subsided, the temperature was raised to 180 ° C., and the imidation polymerization reaction was carried out at the reaction temperature for 2.5 hours. Once the temperature is cooled to 80 ° C., 51.1 g (0.050 mol) of XTJ-542 is added as the polyoxyalkylenediamine component (B), the temperature is raised again to 180 ° C., and imidization is performed at the reaction temperature. The polymerization reaction was carried out for 2.5 hours. Along with the reaction, the produced water azeotroped with ethylcyclohexane, so the distilled water was separated with a liquid separation decanter.
After completion of the reaction, stirring is continued at 180 ° C. for 0.5 hours to distill off and recover the ethylcyclohexane in the reflux liquid, and DMI is added to the reaction system to adjust the concentration of the polyimide resin. A polyimide resin DMI solution (this polyimide varnish) was obtained. Table 1 shows the measurement results of the number average molecular weight, polydispersity, and polyimide resin concentration of the obtained polyimide resin.

(Example 2)
After substituting the inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen introducing tube, a separator decanter, and a cooling tube with nitrogen, 61. HDAM as a dicyclohexane skeleton diamine component (A) under a nitrogen stream. 8 g (0.294 mol), 99.2 g (0.097 mol) of XTJ-542 as a polyoxyalkylenediamine component (B), 980.7 g of DMI as a reaction solvent, and 85.3 g of ethylcyclohexane as a reflux liquid are charged. The diamine was dissolved by stirring at room temperature for 15 minutes. Next, 87.9 g (0.392 mol) of powdered HPMDA as a tetracarboxylic acid component was added with stirring. After a while, salt was formed and an exotherm was observed. After confirming that the exotherm had subsided, the temperature was raised to 180 ° C., and the imidation polymerization reaction was carried out at that reaction temperature for 4 hours. Along with the reaction, the produced water azeotroped with ethylcyclohexane, so the distilled water was separated with a liquid separation decanter.
After completion of the reaction, stirring is continued at 180 ° C. for 0.5 hours to distill off and recover the ethylcyclohexane in the reflux liquid, and DMI is added to the reaction system to adjust the concentration of the polyimide resin. A polyimide resin DMI solution (this polyimide varnish) was obtained. Table 1 shows the measurement results of the number average molecular weight, polydispersity, and polyimide resin concentration of the obtained polyimide resin.

(Example 3)
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen introducing tube, a separator decanter, and a cooling tube was purged with nitrogen, and then HDAM was added as a dicyclohexane skeleton diamine component (A) in an amount of 82. 3 g (0.391 mol), 75.6 g (0.074 mol) of XTJ-542 as the polyoxyalkylenediamine component (B), and 8.6 g (0.025 mol) of FDA as the fluorene skeleton diamine component (C) In addition, 956.8 g of NMP as a reaction solvent and 83.2 g of ethylcyclohexane as a refluxing solution were charged and stirred at room temperature for 15 minutes to dissolve the diamine. Next, 111.0 g (0.495 mol) of powdered HPMDA as a tetracarboxylic acid component was added with stirring. After a while, salt was formed and an exotherm was observed. After confirming that the exotherm had subsided, the temperature was raised to 180 ° C., and the imidation polymerization reaction was carried out at that reaction temperature for 4 hours. Along with the reaction, the produced water azeotroped with ethylcyclohexane, so the distilled water was separated with a liquid separation decanter.
After completion of the reaction, stirring was continued at 180 ° C. for 0.5 hours to distill off and recover the ethylcyclohexane in the reflux liquid, and NMP was added to the reaction system in order to adjust the concentration of the polyimide resin. NMP solution of this polyimide resin (this polyimide varnish) was obtained. Table 1 shows the measurement results of the number average molecular weight, polydispersity, and polyimide resin concentration of the obtained polyimide resin.

Example 4
As the dicyclohexane skeleton component (A), 51.0 g (0.242 mol) of HDAM, as the polyoxyalkylene diamine component (B), 126.8 g (0.124 mol) of XTJ-542, the fluorene skeleton diamine component (C ) Was used in the same manner as in Example 3 except that 43.1 g (0.124 mol) of FDA was used to obtain an NMP solution of the polyimide resin of the present invention (present polyimide varnish). Table 1 shows the measurement results of the number average molecular weight, polydispersity, and polyimide resin concentration of the obtained polyimide resin.

(Example 5)
40.3 g (0.192 mol) of HDAM as the dicyclohexane skeleton diamine component (A), 125.7 g (0.123 mol) of XTJ-542 as the polyoxyalkylene diamine component (B), fluorene skeleton diamine component (C ) Was used in the same manner as in Example 3 except that 59.9 g (0.172 mol) of FDA was used to obtain an NMP solution of the polyimide resin of the present invention (present polyimide varnish). Table 1 shows the measurement results of the number average molecular weight, polydispersity, and polyimide resin concentration of the obtained polyimide resin.

(Comparative Example 1)
After substituting the inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, a liquid separation decanter, and a cooling tube with nitrogen, 150. HDAM as a dicyclohexane skeleton diamine component (A) under a nitrogen stream. 8 g (0.717 mol), 1,233 g of DMI as a reaction solvent, and 217 g of ethylcyclohexane as a refluxing solution were charged and stirred at room temperature for 15 minutes to dissolve the diamine. Subsequently, when 4.04.0 g (0.732 mol) of powdered HPMDA as a tetracarboxylic acid component was added with stirring, a salt precipitated. The mixture was stirred at room temperature for 30 minutes and then heated to 120 ° C. The salt dissolved when it reached 120 ° C. The temperature was further raised and an imidation polymerization reaction was carried out at 180 ° C. for 4 hours. Along with the reaction, the produced water azeotroped with ethylcyclohexane, so the distilled water was separated with a liquid separation decanter.
After completion of the reaction, stirring is continued at 180 ° C. for 0.5 hours to distill off the ethylcyclohexane in the reflux liquid, and the polyimide is recovered by adding DMI to the reaction system in order to adjust the concentration of the polyimide resin. A resin MDI solution (comparative polyimide varnish) was obtained. Table 1 shows the measurement results of the number average molecular weight, polydispersity, and polyimide resin concentration of the obtained polyimide resin.

(Example 6)
A magnetic stirrer was placed in a 100 ml eggplant flask, and 30.0 g of the polyimide varnish obtained in Experimental Example 2 was collected, diluted with 12 g of DMI, and sufficiently stirred at room temperature.
Separately, 2.7 g of DMAC-ST as an organosilica sol was charged in a 100 ml three-necked flask equipped with a thermometer, a stirrer and a nitrogen introduction tube under a nitrogen stream, and diluted with 27 g of DMI and stirred. Furthermore, 0.70 g of KBM-403 was added as a silane coupling agent, heated to 80 ° C. and stirred for 30 minutes. After cooling to room temperature, the previously prepared dilution of the polyimide varnish was added dropwise over 30 minutes. The polyimide varnish was obtained by stirring at 40 degreeC after completion | finish of dripping for 1 hour. Table 2 shows the amounts of organosilica sol and silane coupling agent used.

(Example 7)
This polyimide varnish was obtained in the same manner as in Example 6 except that 8.1 g of DMAC-ST was used as the organosilica sol. Table 2 shows the amounts of organosilica sol and silane coupling agent used.

(Example 8)
This polyimide varnish was obtained in the same manner as in Example 7 except that 0.11 g of KBM-403 was used as the silane coupling agent. Table 2 shows the amounts of organosilica sol and silane coupling agent used.

Example 9
The gap (500 to 1300 μm) is appropriately adjusted by the number of turns of the tape seal so that the polyimide varnish obtained in Examples 1 to 8 and Comparative Example 1 has a predetermined thickness (50 or 80 μm) after the predetermined solvent is distilled off. The obtained glass rod was cast on a PET substrate (polyethylene terephthalate substrate). Subsequently, it was deaerated in a vacuum dryer at room temperature for 1 hour, further heated to 180 ° C. in 0.5 hours, and heat-treated at that temperature for 0.5 hours. After cooling to room temperature and peeling off the film from the substrate, the film was fixed to a stainless steel frame, heated again from room temperature to 250 ° C. in 1.5 hours, and heat-treated at that temperature for 2 hours. . It cooled to room temperature and removed from the metal frame, and this polyimide molding was obtained. Table 3 shows the measurement results of the total light transmittance, yellowness, flexibility test, tensile modulus, elongation at break, and refractive index of the obtained polyimide molded body.

  From Table 1, since the number average molecular weight of each polyimide resin of this invention is 8,000 or more, it turns out that it has a high polymerization degree which can give polyimide molded objects, such as a film.

  From Table 3, since the total light transmittance (film thickness: 80 μm), which is an index of transparency, is 90% or more and the yellowness is 5.0 or less, it is particularly transparent for optical materials and the like. It is effective in applications that place importance on sex.

  In addition, since the evaluation value of the flexibility test, which is an index of flexibility and folding resistance, is 40 or more, it is particularly effective in applications that require flexibility and folding resistance.

  Furthermore, since the elongation at break by a tensile test, which is an index of toughness, is 60% or more, it can be seen that the toughness is high.

  Therefore, as can be seen from Table 3, the polyimide molded body (film form) of the present invention has excellent transparency, flexibility, folding resistance and high toughness, and is particularly useful as an optical material application. I understand.

  Further, from Table 3, the range of the refractive index is 1.512 to 1.548, and within this range, the polyimide molded body with a low refractive index is changed from a polyimide molded body with a low refractive index depending on the application. You can choose.

  The polyimide resin of the present invention is a solvent-soluble polyimide resin. A polyimide molded body obtained by molding a polyimide varnish obtained from the polyimide resin is excellent in transparency, flexibility, folding resistance and toughness, and can be suitably used for optical material applications.

Claims (4)

In the presence of a reaction solvent, at least one tetracarboxylic acid component selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and derivatives thereof, and dicyclohexane represented by the following general formula (1) A skeleton diamine component (A), a polyoxyalkylene diamine component (B) represented by the following general formula (2) and a fluorene skeleton diamine component (C) represented by the following general formula (3),
With respect to the tetracarboxylic acid component 100, the component (A) is 20 to 99, the component (B) is 1 to 40, the component (C) is 0 to 40, and the component (A) + A solvent-soluble polyimide resin obtained by imidation polymerization reaction at a charged molar ratio in which the sum of component (B) + component (C) is in the range of 95 to 105.
General formula (1)
[Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents hydrogen, a methyl group, an ethyl group, a methoxy group or an ethoxy group. Y represents a direct bond, —CH ₂ —, —O—, —S—, —SO ₂ —, —CONH—, —C (—CH ₃ ) ₂ — or —CO—. ]
General formula (2)
[Wherein, R ⁵ represents hydrogen or a methyl group. Z represents a linear or branched alkylene group having 2 to 4 carbon atoms. a, b and c each represent an integer of 0 to 50, and the sum of a + b + c is an integer of 2 to 50. ]
General formula (3)
[Wherein R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same or different and each represents hydrogen, a methyl group or an ethyl group. ]   A polyimide varnish containing the polyimide resin according to claim 1 and an organic solvent.   Furthermore, the polyimide varnish of Claim 2 containing the silica fine particle whose average particle diameter is 0.5-50 nm.   A polyimide molded body obtained by molding the polyimide varnish according to claim 2.