KR20200066302A - Polyimide varnish composition, manufacturing method thereof, and polyimide film - Google Patents

Abstract

The present invention is a polyimide varnish composition containing a polyimide having a structural unit A derived from tetracarboxylic acid or a derivative thereof and a structural unit B derived from diamine and an organic solvent, wherein the structural unit A is 4,4 '- (hexafluoroisopropylidene) containing a structural unit (A-1) derived from diphthalic anhydride, with respect to the total amount of this polyimide varnish composition, at least one organic solvent selected from lactone-based solvents 20 A polyimide varnish composition comprising at least 20% by mass and having a YI of 20 or less measured at a cell of 23°C and an optical path length of 10 mm of the polyimide varnish composition, a method for producing the polyimide varnish composition, and a polyyi obtained from the polyimide varnish composition Provided is a polyimide varnish composition, a polyimide varnish composition capable of forming a film having excellent colorless and transparent properties, a method for producing the same, and a polyimide varnish composition.

Description

Polyimide varnish composition, manufacturing method thereof, and polyimide film

The present invention relates to a polyimide varnish composition, a method for producing the same, and a polyimide film.

In general, polyimide is obtained from aromatic tetracarboxylic acid anhydride and aromatic diamine, and has excellent heat resistance, chemical resistance, mechanical properties, and electrical properties due to molecular rigidity, resonance stabilization, and strong chemical bonding. , Electrical and electronic parts, optical materials, displays, and aerospace.

In recent years, properties such as colorless transparency and solvent solubility as polyimide have been required. However, the conventional polyimide had problems such as a high haze value and a high yellow index (YI: yellowness).

For example, Patent Document 1 discloses a polyimide film produced using a fluorinated diamine and a fluorinated acid anhydride, and having a haze value of 4 or less, a YI of 3 or less, and a fluorinated polyimide layer having a total light transmittance of 90% or more. It is.

Japanese Patent Publication No. 2016-27146

However, the polyimide film of Patent Document 1 is produced through a process of purifying a fluorinated polyimide solution by reprecipitation. Accordingly, it is desired to improve the colorless transparency of the polyimide film in a simpler way.

That is, the problem to be solved by the present invention is to provide a polyimide varnish composition capable of forming a film excellent in colorless transparency, a manufacturing method thereof, and a polyimide film obtained from the polyimide varnish composition.

As a result of careful review by the inventors, the YI of the polyimide varnish composition containing a polyimide composed of a specific structural unit and a specific organic solvent is greatly reduced, and the polyimide film obtained from the varnish composition is colorless and transparent. I found something excellent. Based on these findings, the present invention has been reached. That is, the present invention relates to the following [1] to [3].

[1] A polyimide varnish composition containing a polyimide and an organic solvent,

This polyimide has a structural unit A derived from tetracarboxylic acid or a derivative thereof, and a structural unit B derived from diamine,

This structural unit A contains the structural unit (A-1) derived from the compound represented by the following formula (a-1),

With respect to the total amount of the polyimide varnish composition, at least one organic solvent selected from lactone-based solvents is contained in an amount of 20% by mass or more,

The polyimide varnish composition having a YI of 20 or less measured in a cell of 23°C and an optical path length of 10 mm of this polyimide varnish composition.

[Formula 1]

[2] A polyimide film obtained from the polyimide varnish composition.

[3] Diamine components and 4,4'-(hexafluoroisopropylidene)diphthalic acid or derivatives thereof in the presence of at least one organic solvent selected from lactone-based solvents and in the absence of catalysts and dehydrating agents. As a method for producing a polyimide varnish composition containing a polyimide and an organic solvent by reacting a tetracarboxylic acid component containing, the content of the lactone-based solvent relative to the total amount of the polyimide varnish composition is 20% by mass or more, A method for producing a polyimide varnish composition, wherein the polyimide varnish composition has a YI of 20 or less measured in a cell having a light path length of 10 mm and a temperature of 23°C.

ADVANTAGE OF THE INVENTION According to this invention, the polyimide varnish composition which can form the film excellent in colorless transparency, its manufacturing method, and the polyimide film obtained from this polyimide varnish composition can be provided.

The polyimide varnish composition of the present invention contains a polyimide and an organic solvent. On the other hand, the polyimide varnish composition of the present invention may be simply abbreviated as "varnish composition."

Hereinafter, the polyimide varnish composition of the present invention will be described.

The polyimide contained in the varnish composition of the present invention has a structural unit A derived from tetracarboxylic acid or a derivative thereof and a structural unit B derived from diamine, and the structural unit A is represented by the following formula (a-1). It contains the structural unit (A-1) derived from the compound shown.

[Formula 2]

〔Composition unit A〕

The structural unit A contained in the polyimide according to the present invention is a structural unit derived from tetracarboxylic acid or a derivative thereof. Tetracarboxylic acid or a derivative thereof can be used alone or in combination of two or more.

As a derivative of tetracarboxylic acid, anhydride or alkyl ester of tetracarboxylic acid is mentioned. As alkyl ester of tetracarboxylic acid, it is preferable that carbon number of alkyl is 1-3, For example, dimethyl ester, diethyl ester, and dipropyl ester of tetracarboxylic acid are mentioned. As tetracarboxylic acid or its derivative, tetracarboxylic dianhydride is preferable.

The structural unit A contains the structural unit (A-1) derived from the compound represented by the formula (a-1). When the structural unit A contains the structural unit (A-1), the colorless transparency of the film is improved.

The ratio of the structural unit (A-1) to the structural unit A is preferably 30 mol% or more, more preferably 35 mol% or more, still more preferably 40 mol% or more, even more preferably 45 mol% Or more, even more preferably 50 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 80 mol% or less, It is even more preferably 70 mol% or less, and even more preferably 60 mol% or less.

It is preferable that the structural unit A further includes a structural unit (A-2) derived from a compound represented by the following formula (a-2) from the viewpoints of heat resistance, mechanical properties (elastic modulus) and organic solvent resistance.

[Formula 3]

As a compound represented by Formula (a-2), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following Formula (a-2-1), the following Formula 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) represented by (a-2-2), 2,2' represented by the following formula (a-2-3), 3,3'-biphenyltetracarboxylic dianhydride (i-BPDA) is mentioned, and among them, 3,3',4,4'-biphenyltetracar represented by the following formula (a-2-1) This acid dianhydride is preferred. The compound represented by formula (a-2) can be used alone or in combination of two or more.

s-BPDA is preferred from the viewpoint of organic solvent resistance, and a-BPDA and i-BPDA are preferred from the viewpoint of heat resistance and solution processability.

[Formula 4]

The ratio of the structural unit (A-2) to the structural unit A is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably from the viewpoints of heat resistance, mechanical properties (elastic modulus), and organic solvent resistance. It is preferably 20 mol% or more, even more preferably 30 mol% or more, and even more preferably 40 mol% or more. The ratio of (A-2) is preferably 70 mol% or less, more preferably 65 mol% or less, more preferably 60 mol% or less, and even more preferably from the viewpoint of improving the colorless transparency of the film. 55 mol% or less, even more preferably 50 mol% or less.

When the structural unit A contains the structural unit (A-2), the molar ratio [(A-1)/(A-2)] of the structural unit (A-1) and the structural unit (A-2) is colorless From the viewpoints of transparency, heat resistance, and mechanical properties (elastic modulus), 30/70 to 95/5 are preferable, 35/65 to 90/10 are more preferable, 40/60 to 80/20 are more preferable, and 45/ 55-70/30 are more preferable, and 50/50-60/40 are more preferable.

In the structural unit A constituting the polyimide according to the present invention, the proportion occupied by the sum of the structural units (A-1) and structural units (A-2) is preferably 70 to 100 mol%, more preferably 85-100 mol%, more preferably 99-100 mol%, even more preferably 100 mol%.

The polyimide according to the present invention has the formula (a-) as a structural unit other than the structural units (A-1) and (A-2) in the structural unit A, within a range not impairing the effects of the present invention. The structural units derived from tetracarboxylic dianhydride other than the compounds represented by 1) and (a-2) may be included, but it is preferable not to.

(Composition unit B)

The structural unit B contained in the polyimide according to the present invention is a structural unit derived from diamine. These diamines can be used alone or in combination of two or more.

The structural unit B preferably includes at least one member selected from the group consisting of a structural unit derived from an aliphatic diamine, and a structural unit derived from an aromatic diamine, more preferably a structural unit derived from an aliphatic diamine, And structural units derived from aromatic diamines.

By containing the structural unit derived from an aliphatic diamine in the said structural unit B, organic solvent resistance and colorless transparency are improved.

Meanwhile, in the present invention, “aliphatic diamine” refers to a diamine in which an amino group is directly bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and an aliphatic group, alicyclic group, aromatic group, or other substituent (for example, a part of the structure) , Halogen atom, sulfonyl group, carbonyl group, oxygen atom, etc.). “Aromatic diamine” refers to a diamine in which an amino group is directly bonded to an aromatic ring, and part of the structure may include an aliphatic group, an alicyclic group, an aromatic group, and other substituents. For example, metaxylylenediamine is an aliphatic diamine because the amino group is directly bonded to an aliphatic hydrocarbon group (methylene group).

As a structural unit derived from an aliphatic diamine, a structural unit (B-1) derived from the compound represented by the following formula (b-1), a structural unit (B-2) derived from the following formula (b-2), And at least one member selected from the group consisting of structural units (B-3) derived from the compound represented by the following formula (b-3), and structural units derived from the following formula (b-2) ( It is more preferable to include B-2). When the said structural unit B contains at least 1 sort(s) selected from the group which consists of structural units (B-1) and (B-2), organic solvent resistance and colorless transparency are improved. When the structural unit B has the structural unit (B-3), mechanical properties (elastic modulus) and colorless transparency are improved.

[Formula 5]

The cis:trans ratio of the compound represented by formulas (b-1) and (b-2) is preferably 0:100 to 100:0, and 0:100 to 0,100 from the viewpoint of organic solvent resistance and heat resistance, respectively. 80:20 is more preferable, 0.1:99.9 to 70:30 is more preferable, 0.5:99.5 to 60:40 is more preferable, and 1:99 to 20:80 is still more preferable.

The ratio of the total amount of the structural units derived from the aliphatic diamine to the structural unit B is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, from the viewpoint of organic solvent resistance and colorless transparency. 20 to 80 mol% is more preferable, 35 to 75 mol% is more preferable, and 45 to 60 mol% is even more preferable.

The proportion of the total of the structural units (B-1), (B-2), and (B-3) in the structural units derived from the aliphatic diamine is 60 mol% or more from the viewpoint of organic solvent resistance and colorless transparency. It is preferable, 80 mol% or more is more preferable, 90 mol% or more is more preferable, and 100 mol% or more is more preferable.

As a structural unit derived from an aromatic diamine, it is preferable to include the structural unit (B-4) derived from the compound represented by the following formula (b-4) from a viewpoint of heat resistance and mechanical properties.

[Formula 6]

The ratio of the structural unit (B-4) to the structural unit B is preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less, from the viewpoint of organic solvent resistance. Even more preferably 65 mol% or less, even more preferably 55 mol% or less, from the viewpoint of heat resistance and mechanical properties, preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, even more preferably 20 mol% or more, even more preferably 25 mol% or more, even more preferably 40 mol% or more.

The proportion of the structural unit (B-4) in the structural unit derived from the aromatic diamine is preferably 60 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, 100 Molar% is more preferred.

The proportion of the total of the constituent units derived from the aromatic diamine to the constituent unit B is preferably 5 to 90 mol%, more preferably 10 to 85 mol%, from the viewpoints of heat resistance, mechanical properties, and organic solvent resistance. And more preferably 20 to 80 mol%, more preferably 25 to 65 mol%, and even more preferably 40 to 55 mol%.

The proportion of the total of the structural units (B-1) to (B-4) with respect to the structural unit B is preferably 70 to 100 mol%, more preferably 85 to 100 mol%, and even more preferably 99-100 mol%, more preferably 100 mol%.

The polyimide according to the present invention includes, in a range not impairing the effects of the present invention, constituent units derived from diamines other than the compounds represented by formulas (b-1) to (b-4) in the constituent units B It may be, but it is preferable that it is not included.

(Method for producing polyimide)

The polyimide is obtained by reacting the tetracarboxylic acid component that gives the structural unit A and the diamine component that gives the structural unit B.

As a tetracarboxylic acid component which gives a structural unit A, tetracarboxylic acid or its derivative(s) is mentioned. The tetracarboxylic acid components may be used alone or in combination of two or more.

Examples of the derivative of tetracarboxylic acid include anhydride or alkyl ester of this tetracarboxylic acid.

As alkyl ester of tetracarboxylic acid, it is preferable that carbon number of alkyl is 1-3, For example, dimethyl ester, diethyl ester, and dipropyl ester of tetracarboxylic acid are mentioned.

The tetracarboxylic acid component is essential to include 4,4'-(hexafluoroisopropylidene)diphthalic acid or derivatives thereof, and preferably 4,4'-(hexafluoroisopropylidene)diphthalic acid Anhydride [Formula (a-1) above] is included.

Furthermore, it is preferable that the tetracarboxylic acid component contains biphenyltetracarboxylic acid and its derivatives, and it is more preferable to include biphenyltetracarboxylic dianhydride [Formula (a-2)], and 3,3 It is more preferable to include',4,4'-biphenyltetracarboxylic dianhydride [Formula (a-2-1) above].

The amount of the 4,4'-(hexafluoroisopropylidene) diphthalic acid or derivative thereof is preferably 30 to 100 mol%, more preferably 35 to the total tetracarboxylic acid component from the viewpoint of colorless transparency. ~95 mol%, more preferably 40-90 mol%, even more preferably 45-80 mol%, even more preferably 50-70 mol%, even more preferably 50-60 mol%.

The amount of biphenyltetracarboxylic acid and its derivatives used is preferably 70 mol% or less, more preferably 5 to 65, based on the total tetracarboxylic acid component from the viewpoints of heat resistance, mechanical properties (elastic modulus), and organic solvent resistance. Molar%, more preferably 10 to 60 mol%, even more preferably 20 to 55 mol%, even more preferably 30 to 50 mol%, even more preferably 40 to 50 mol%.

Furthermore, 4,4'-(hexafluoroisopropylidene) diphthalic acid and its derivatives, and biphenyltetracarboxylic acid and tetracarboxylic acid components other than its derivatives (hereinafter also referred to as "other tetracarboxylic acid components") It may contain.

Examples of the other tetracarboxylic acid component include tetracarboxylic acid containing an aromatic ring or derivatives thereof, and tetracarboxylic acid containing an alicyclic hydrocarbon structure or derivatives thereof. Other tetracarboxylic acid components may be used alone or in combination of two or more.

Examples of the tetracarboxylic acid containing an aromatic ring or a derivative thereof include pyromellitic acid, 3,3',4,4'-diphenylsulfonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid , 4,4'-oxydiphthalic acid, 2,2',3,3'-benzophenonetetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2, 3-dicarboxyphenyl)propane, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane, 1,1-bis(2,3-dicarboxyphenyl)ethane, 1,2-bis(2, 3-dicarboxyphenyl)ethane, 1,1-bis(3,4-dicarboxyphenyl)ethane, 1,2-bis(3,4-dicarboxyphenyl)ethane, bis(2,3-dicarboxyphenyl) Methane, bis(3,4-dicarboxyphenyl)methane, 4,4'-(p-phenylenedioxy)diphthalic acid, 4,4'-(m-phenylenedioxy)diphthalic acid, 2,3,6, And 7-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,5,6-toluenetetracarboxylic acid, and derivatives thereof.

Tetracarboxylic acids or derivatives thereof containing an alicyclic hydrocarbon structure include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,4,5-cyclopentanetetracarboxylic acid, 1,2,4, 5-cyclohexanetetracarboxylic acid, bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic acid, dicyclohexyltetracarboxylic acid, and cyclopentanonebisspironobonantetracar And the acid or their positional isomers and their derivatives.

Tetracarboxylic acids or derivatives thereof that do not include both alicyclic hydrocarbon structures and aromatic rings include 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, or the like. And derivatives.

The amount of the other tetracarboxylic acid component is preferably 30 mol% or less, more preferably 15 mol% or less, more preferably 1 mol% or less, even more preferably 0 mol with respect to the total tetracarboxylic acid component. %to be.

The diamine component constituting the structural unit B is not particularly limited, but is preferably at least one selected from the group consisting of aliphatic diamines and aromatic diamines, from the viewpoint of colorless transparency, heat resistance, and mechanical properties, and aliphatic diamines. It is more preferable to include, and aromatic diamine. On the other hand, the diamine component that gives the structural unit B is not limited to diamine, and may be a derivative thereof (such as diisocyanate) in the range in which the same structural unit is formed, but diamine is preferred.

The aliphatic diamine preferably has 2 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 6 to 8 carbon atoms.

Examples of the aliphatic diamine include hexamethylenediamine, polyethylene glycol bis(3-aminopropyl) ether, polypropylene glycol bis(3-aminopropyl) ether, and 1,3-bis(aminomethyl)cyclohexane [above] Formula (b-2)], 1,4-bis(aminomethyl)cyclohexane [formula (b-1) above], metaxylylenediamine [formula (b-3) above], paraxylylenediamine, 1, 4-bis(2-amino-isopropyl)benzene, 1,3-bis(2-amino-isopropyl)benzene, isophoronediamine, norbornanediamine, siloxanediamine, 4,4'-diaminodicyclohexylmethane , 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodicyclohexylmethane, 3,3',5,5'- Tetramethyl-4,4'-diaminodicyclohexylmethane, 2,3-bis(aminomethyl)-bicyclo[2.2.1]heptane, 2,5-bis(aminomethyl)-bicyclo[2.2.1 ]Heptane, 2,6-bis(aminomethyl)-bicyclo[2.2.1]heptane, 2,2-bis(4,4'-diaminocyclohexyl)propane, 2,2-bis(4,4' -Diaminomethylcyclohexyl)propane. These may be used alone or in combination of two or more.

As the aliphatic diamine, among them, 1,3-bis(aminomethyl)cyclohexane [formula (b-2)], 1,4-bis(aminomethyl)cyclohexane [formula (b-1)], It is preferable to include at least one selected from the group consisting of metaxylylenediamine [Formula (b-3)] and paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4- It is more preferable to include at least one selected from the group consisting of bis(aminomethyl)cyclohexane and metaxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, and 1,4-bis(amino) It is more preferable to include at least one selected from the group consisting of methyl)cyclohexane, and even more preferably to include 1,3-bis(aminomethyl)cyclohexane.

From the viewpoints of organic solvent resistance and colorless transparency, the total amount of the aliphatic diamine used is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, and even more preferably 20 to 80 mol%, relative to the total diamine component. And 35 to 75 mol% is more preferable, and 45 to 60 mol% is even more preferable.

The total amount of the aliphatic diamine represented by the formulas (b-1), (b-2) and (b-3) is 60 from the viewpoint of organic solvent resistance and colorless transparency, based on the total amount of the aliphatic diamine in the total diamine component. Molar% or more is preferable, 80 mol% or more is more preferable, 90 mol% or more is more preferable, and 100 mol% is even more preferable.

The amount of the aliphatic diamine other than the aliphatic diamine represented by the formulas (b-1), (b-2) and (b-3) is preferably 10 mol% or less, more preferably 5, based on the total diamine component. Mol% or less, more preferably 1 mol% or less, even more preferably 0 mol%.

Examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, benzidine, o-tolidine, m-tolidine, Bis(trifluoromethyl)benzidine [formula (b-4)], octafluorobenzidine, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dimethoxy- 4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,6- Diaminonaphthalene, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'- Diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2,2- Bis[4-(2-methyl-4-aminophenoxy)phenyl]propane, 2,2-bis[4-(2,6-dimethyl-4-aminophenoxy)phenyl]propane, 2,2-bis( 4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis[4-(2-methyl-4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4- (2,6-dimethyl-4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(2-methyl-4-amino Phenoxy)biphenyl, 4,4'-bis(2,6-dimethyl-4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, bis[4-(4 -Aminophenoxy)phenyl]sulfone, bis[4-(2-methyl-4-aminophenoxy)phenyl]sulfone, bis[4-(2,6-dimethyl-4-aminophenoxy)phenyl]sulfone, bis [4-(4-aminophenoxy)phenyl]ether, bis[4-(2-methyl-4-aminophenoxy)phenyl]ether, bis[4-(2,6-dimethyl-4-aminophenoxy) Phenyl]ether, 1,4-bis(4-aminophenoxy)benzene, 1,4-bis(2-methyl-4-aminophenoxy)benzene, 1,4-bis(2,6-dimethyl-4- Aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(2-methyl-4-aminophenoxy)benzene, 1,3-bis(2,6-dimethyl- 4-aminophenoxy)benzene, 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene,

2,2-bis(4-aminophenyl)propane, 2,2-bis(2-methyl-4-aminophenyl)propane, 2,2-bis(3-methyl-4-aminophenyl)propane, 2,2 -Bis(3-ethyl-4-aminophenyl)propane, 2,2-bis(3,5-dimethyl-4-aminophenyl)propane, 2,2-bis(2,6-dimethyl-4-aminophenyl) Propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(2-methyl-4-aminophenyl)hexafluoropropane, 2,2-bis(2,6-dimethyl- 4-aminophenyl)hexafluoropropane, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, α,α'-bis(2-methyl-4-aminophenyl)-1 ,4-diisopropylbenzene, α,α'-bis(2,6-dimethyl-4-aminophenyl)-1,4-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1 ,4-diisopropylbenzene, α,α'-bis(4-aminophenyl)-1,3-diisopropylbenzene, α,α'-bis(2-methyl-4-aminophenyl)-1,3 -Diisopropylbenzene, α,α'-bis(2,6-dimethyl-4-aminophenyl)-1,3-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,3 -Diisopropylbenzene, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(2-methyl-4-aminophenyl)fluorene, 9,9-bis(2,6-dimethyl- 4-aminophenyl)fluorene, 9,9-bis(3-fluoro-4-aminophenyl)fluorene, 9,9-bis(3-methyl-4-aminophenyl)fluorene, 5-amino-1 ,3,3-trimethyl-1-(4-aminophenyl)-indan, 1,1-bis(4-aminophenyl)cyclopentane, 1,1-bis(2-methyl-4-aminophenyl)cyclopentane, 1,1-bis(2,6-dimethyl-4-aminophenyl)cyclopentane, 1,1-bis(4-aminophenyl)cyclohexane, 1,1-bis(2-methyl-4-aminophenyl)cyclo Hexane, 1,1-bis(2,6-dimethyl-4-aminophenyl)cyclohexane, 1,1-bis(4-aminophenyl)4-methyl-cyclohexane, 1,1-bis(4-aminophenyl) )Novonan, 1,1-bis(2-methyl-4-aminophenyl)norbonane, 1,1-bis(2,6-dimethyl-4-aminophenyl)norbonane, 1,1-bis(4- Aminophenyl) adamantane, 1,1-bis(2-methyl-4-aminophenyl) adamantane, 1,1-bis(2,6-dimethyl-4 -Aminophenyl) adamantane and the like. These may be used alone or in combination of two or more.

Among these, 2,2'-bis(trifluoromethyl)benzidine [formula (b-4)] is preferable from the viewpoint of heat resistance and mechanical properties.

The amount of aromatic diamine used is preferably from 5 to 90 mol%, more preferably from 10 to 85 mol%, even more preferably from 20 to 80, relative to the total diamine component, from the viewpoint of organic solvent resistance, heat resistance and mechanical properties. Molar%, more preferably 25 to 65 mol%, even more preferably 40 to 55 mol%.

The amount of aromatic diamines other than 2,2'-bis(trifluoromethyl)benzidine is preferably 20 mol% or less, more preferably 10 mol% or less, further preferably 1 mol with respect to the total diamine component. % Or less, even more preferably 0 mol%.

When preparing the polyimide according to the present invention, it is preferable that the diamine component is 0.9 to 1.1 moles relative to 1 mole of the tetracarboxylic acid component in the input ratio of the tetracarboxylic acid component and the diamine component.

When preparing the polyimide according to the present invention, in addition to the tetracarboxylic acid component and the diamine component, a terminal sealant may be used. As the terminal blocker, monoamines or dicarboxylic acids are preferred. As an input amount of the terminal sealing agent to be introduced, 0.0001 to 0.1 mol is preferable, and 0.001 to 0.06 mol is more preferable with respect to 1 mol of the tetracarboxylic acid component. Examples of the monoamine terminal blockers include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, and 3-methylbenzylamine. , 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like are recommended. Of these, benzylamine and aniline can be suitably used. Dicarboxylic acids are preferable as the terminal sealing agent for dicarboxylic acids, and a part of them may be closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid, Cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. are recommended. Of these, phthalic acid and phthalic anhydride can be suitably used.

The method for reacting the above-mentioned tetracarboxylic acid component and diamine component is not particularly limited, and a known method can be used.

As a specific reaction method, (1) a method of introducing a tetracarboxylic acid component, a diamine component, and a reaction solvent into a reactor, stirring at room temperature to 80°C for 0.5 to 30 hours, and then raising the temperature to perform an imidization reaction, ( 2) After dissolving the diamine component and the reaction solvent in a reactor, a tetracarboxylic acid component is added, and if necessary, the mixture is stirred at room temperature to 80°C for 0.5 to 30 hours, and then heated to perform an imidization reaction. And (3) a method in which a tetracarboxylic acid component, a diamine component, and a reaction solvent are introduced into a reactor, and the temperature is raised immediately to perform an imidization reaction.

The reaction solvent used in the production of the polyimide may be any one that can dissolve the resulting polyimide without inhibiting the imidation reaction, but is preferably locked from the viewpoint of reducing the YI of the polyimide varnish composition of the present invention. At least one organic solvent selected from tone-based solvents is selected. The above reaction solvents may be used alone or in combination of two or more.

Examples of the lactone-based solvent include γ-butyrolactone and γ-valerolactone, and among them, γ-butyrolactone is preferable.

Reactive solvents other than lactone solvents may be used, but from the viewpoint of reducing the YI of the polyimide varnish composition, N,N-dimethylisobutylamide, N,N-dimethylformamide, N,N-dimethylacetamide, N -Amide solvents such as methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, amine solvents such as picoline and pyridine, and hexamethylphosphoricamide It is preferable not to contain a phosphorus-based amide solvent such as hexamethylphosphine triamide.

When the amide-based solvent, amine-based solvent, and phosphorus-based amide-based solvent are contained in the reaction system as a reaction system solvent, YI of the resulting varnish composition increases with the temperature rise in the imidization reaction, and the colorless transparency of the polyimide film It cannot be avoided that it falls.

Reaction solvents other than lactone-based solvents include, for example, phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylole Phenolic solvents such as phenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol, sulfur-based solvents such as dimethylsulfone, dimethylsulfoxide and sulfolane, acetone and cyclohexa Ketone solvents such as paddy and methylcyclohexanone, ester solvents such as acetic acid (2-methoxy-1-methylethyl), 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1, Ether-based solvents such as 2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane, diethyl carbonate, methyl And carbonate-based solvents such as ethyl carbonate, ethylene carbonate, and propylene carbonate. Among these, phenolic solvents are preferred.

The total content of the lactone-based solvent relative to the total amount of the reaction solvent used in the production of the polyimide is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, Even more preferably, it is 100 mass %.

In the imidation reaction, it is preferable to carry out the reaction while removing water generated during production using a Dean Stark apparatus or the like. By performing such an operation, the polymerization degree and the imidation rate can be further increased.

In the reaction of the diamine component and the tetracarboxylic acid component, after completion of the imidization reaction, a polyimide solution containing at least a polyimide and a reaction solvent can be obtained.

In the reaction between the diamine component and the tetracarboxylic acid component, a catalyst and a dehydrating agent can be suitably used within a range that does not impair the effects of the present invention, but it is preferable to react under conditions where the catalyst and the dehydrating agent are not present. Among them, pyridine derivatives such as pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tri It is preferable to perform the above imidization reaction without using tertiary amines such as butylamine, N,N-dimethylaniline, N,N-diethylaniline and triethylenediamine. In the present invention, by reacting a diamine component and a tetracarboxylic acid component under conditions where no catalyst and dehydrating agent are present, the imidization reaction is completed in a shorter reaction time than when a tertiary amine such as triethylamine is used as the imidization catalyst. It became clear that YI of the obtained polyimide varnish composition was significantly reduced.

The temperature of the imidation reaction is preferably 120 to 350°C, more preferably 160 to 250°C, and still more preferably 170 to 190°C, from the viewpoint of improving the reaction rate and suppressing gelation and the like. Further, the reaction time is preferably 0.5 to 10 hours, more preferably 1 to 8 hours, and even more preferably 2 to 6 hours after the start of the outflow of product water.

[Polyimide]

The weight average molecular weight of the polyimide according to the present invention is preferably 500 to 1,000,000, more preferably 5,000 to 100,000, from the viewpoint of the mechanical strength of the resulting polyimide film. On the other hand, the weight average molecular weight of the polyimide can be measured by gel filtration chromatography or the like.

As a measurement example of the weight average molecular weight, a method of measuring the absolute molecular weight with a light scattering detector using N,N-dimethylformamide as a developing solvent can be given.

〔Polyimide varnish composition and preparation method therefor〕

The polyimide varnish composition of the present invention includes the polyimide and the organic solvent according to the present invention. In the varnish composition of the present invention, the polyimide is dissolved in the organic solvent. The polyimide varnish composition of the present invention may be a polyimide solution itself obtained by the reaction of the above-described diamine component and tetracarboxylic acid component. Further, at least one organic solvent selected from diluents described later may be mixed with the polyimide solution.

As the organic solvent contained in the varnish composition, it is preferable to include at least an organic solvent used as a reaction solvent. The content of the organic solvent used as the reaction solvent is preferably 20% by mass or more, more preferably 22% by mass or more, with respect to the total amount of the polyimide varnish composition, from the viewpoint of solubility of the polyimide and processability for the polyimide film. , More preferably 24% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less. The content of the lactone-based solvent contained in the varnish composition is 20 mass% or more, preferably 22 mass% or more, more preferably 24 mass% or more, and preferably 50 mass% or more, relative to the total amount of the polyimide varnish composition. Hereinafter, it is more preferably 40% by mass or less.

The polyimide varnish composition of the present invention may further mix various additives within a range not impairing the effects of the present invention. Examples of the additives include antioxidants, light stabilizers, surfactants, flame retardants, plasticizers, inorganic fillers, and polymer compounds other than the polyimide.

As the polymer compound, polyesters such as polyimide, polycarbonate, polystyrene, polyamide, polyamideimide, and polyethylene terephthalate other than polyimide according to the present invention, polyether sulfone, polycarboxylic acid, polyacetal, polyphenylene And ether, polysulfone, polybutylene, polypropylene, polyacrylamide, and polyvinyl chloride.

The solid content concentration of the polyimide varnish composition can be appropriately selected depending on the workability and the like when forming the polyimide film to be described later, and the reaction solvent used in the production of the polyimide according to the present invention is volatilized or condensed, or diluted The solid content concentration and viscosity of the polyimide varnish composition of the present invention can also be adjusted by adding an organic solvent as a solvent.

By adjusting the solid content concentration or viscosity of the polyimide varnish composition as described above, the thickness of the polyimide film according to the present invention described later can be easily controlled, and the polyimide film can be easily produced.

The diluting solvent is not particularly limited as long as it can dissolve the polyimide, but it is preferable to include an amide-based solvent from the viewpoint of solubility of the polyimide and ease of solvent removal when processing the polyimide film. Do.

Specific examples of the amide-based solvent include N,N-dimethylisobutylamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-methylcaprolactam, And 1,3-dimethylimidazolidinone, tetramethylurea, and the like. Among these, N,N-dimethylacetamide is preferred.

The content of the diluting solvent relative to the total amount of the varnish composition is preferably 70 mass% or less, more preferably 65 mass% or less, still more preferably 60 mass% or less, and preferably 10 mass% or more, 20 mass % Or more and 25% by mass or more. It is preferable that the content of the amide-based solvent used as a diluting solvent contained in the varnish composition is also in the same range as above.

In the present invention, even when an amide-based solvent is used as a diluting solvent, YI of the varnish composition can be reduced and a polyimide excellent in colorless transparency can be produced.

The solid content concentration of the polyimide varnish composition of the present invention is not particularly limited, but is preferably 5 to 60 mass%, more preferably 10 to 45 mass%, even more preferably 10 to 30 mass%, and 15 to 25 mass% % Is more preferred.

The viscosity of the polyimide varnish composition of the present invention at 25°C is preferably 1 to 200 Pa·s, more preferably 5 to 150 Pa·s, and even more preferably 10 to 100 Pa·s.

The yellow index (YI) of the polyimide varnish composition of the present invention can be preferably 20 or less, more preferably 15 or less, further preferably 12 or less, and even more preferably 10 or less. When the YI of the polyimide varnish composition is 20 or less, the YI of the polyimide film obtained from this polyimide varnish composition is reduced, and a polyimide film excellent in colorless transparency can be obtained. The YI of the polyimide varnish composition of the present invention is a value measured by a cell at 23°C and an optical path length of 10 mm, and can be specifically measured by the method described in Examples. The solid content concentration for measuring the YI of the varnish composition is not particularly limited, but for example, it is preferable to use a varnish composition in which the solid content concentration is adjusted to 20% by mass.

The total content of tertiary amines, pyridine derivatives, and impurities derived therefrom contained in the polyimide varnish composition of the present invention is preferably 30 mass ppm or less, more preferably 20 mass ppm or less, with respect to the polyimide, It is more preferable that it is 10 ppm by mass or less. If the total content of the tertiary amine, pyridine derivative, and impurities derived from the polyimide varnish composition is 30 ppm by mass or less, a polyimide varnish composition having a YI of 20 or less can be prepared, and polyyi excellent in colorless transparency A mid film can be formed. The total content of tertiary amines, pyridine derivatives, and impurities derived from these contained in the polyimide varnish composition can be specifically measured by the method described in Examples. As a tertiary amine and a pyridine derivative, the thing similar to what was illustrated above is mentioned.

In the reaction of the diamine component and the tetracarboxylic acid component, it is generally practiced to use tertiary amines or pyridine derivatives as imidation catalysts, dehydrating agents, or solvents. Then, it is thought that tertiary amine, a pyridine derivative or a compound derived from these exists as an impurity in the polyimide solution, and as a result, the YI of the varnish composition is deteriorated. In the present invention, from the viewpoint of reducing the YI of the varnish composition, a tertiary amine, a pyridine derivative, included in the polyimide varnish composition, by reacting a diamine component and a tetracarboxylic acid component without using a tertiary amine and a pyridine derivative, And the total content of impurities derived from these can be 30 ppm by mass or less.

[Polyimide Film]

The polyimide film of the present invention is characterized by being obtained from the polyimide varnish composition of the present invention, and is excellent in colorless transparency. It is preferable that the polyimide film of this invention consists of polyimide contained in the polyimide varnish composition of this invention.

The method for producing the polyimide film of the present invention is not particularly limited, and a known method can be used. For example, after the polyimide varnish composition of the present invention is coated on a smooth support such as a glass plate, a metal plate, or plastic, or molded into a film shape, a method of removing the solvent component contained in the varnish composition is mentioned. Can be.

A mold release agent may be applied to the surface of the support, if necessary. As a method of removing the solvent component by heating after applying the polyimide varnish composition to the support, the following method is preferable. That is, after evaporating the solvent component at a temperature of 120° C. or lower to obtain a self-supporting film, the self-supporting film is peeled from the support, the end of the self-supporting film is fixed, and the boiling point of the used solvent component is 350 or more. It is preferable to produce a polyimide film by drying at a temperature of ℃ or lower. In addition, it is preferable to dry under a nitrogen atmosphere. The pressure of the dry atmosphere may be any of reduced pressure, normal pressure and pressurization.

The thickness of the polyimide film of the present invention can be appropriately selected depending on the application and the like, but is preferably in the range of 1 to 250 μm, more preferably 5 to 100 μm, and more preferably 10 to 90 μm. When the thickness is 1 to 250 μm, practical use as a freestanding film becomes possible.

In the present invention, the total light transmittance at a thickness of 80 μm is preferably 80% or more, more preferably 85% or more, and even more preferably a polyimide film of 88% or more.

In the present invention, the yellow index (YI) at a thickness of 80 µm is preferably 3.5 or less, more preferably 3.3 or less, more preferably 3.1 or less, and even more preferably a polyimide film of 2.6 or less. .

In the present invention, haze at a thickness of 80 µm is preferably 1.0% or less, more preferably 0.8% or less, more preferably 0.7% or less, even more preferably a polyimide film of 0.6% or less. .

The total light transmittance, YI, and haze of the polyimide film can be specifically measured by the method described in Examples.

In the present invention, when the total light transmittance of the polyimide film having a thickness of 80 μm is 80% or more, YI is 3.5 or less, and haze is 1.0% or less, it can be said that the polyimide film is excellent in colorless transparency. In other words, it is preferable that the polyimide film of the present invention has a YI of 3.5 or less, a total light transmittance of 80% or more, and a haze of 1.0% or less as a property value at a thickness of 80 μm.

In the present invention, the glass transition temperature is preferably 200°C or higher, more preferably 220°C or higher, more preferably 235°C or higher, and even more preferably 250°C or higher.

The polyimide film obtained from the polyimide varnish composition of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members.

Example

The present invention will be specifically described by the following examples. However, the present invention is not limited at all by these examples.

The properties of the varnish composition and the polyimide film obtained in the following Examples and Comparative Examples were measured by the methods shown below.

(1) Total light transmittance, yellow index (YI), haze:

The total light transmittance, YI, and haze of the polyimide film were measured using a color and turbidity measuring instrument "COH400" manufactured by Japan Color Industries, Ltd.

The YI of the varnish composition was measured by calculating the varnish composition in a quartz glass cell having a width of 10 mm and measuring at 23°C in the same manner as above.

The measurement of total light transmittance and YI was based on JIS K7361-1:1997, and the measurement of haze was based on JIS K7136:2000.

(2) Solid content concentration:

The solid content concentration of the polyimide varnish composition was calculated from the sample weight difference before and after heating the sample by heating it at 300°C x 30 min with MMF-1 using a small electric machine manufactured by As One Corporation.

(3) Polyimide film thickness:

The polyimide film thickness was measured using a micrometer manufactured by Mitsutoyo Corporation.

(4) Viscosity of the polyimide varnish composition

The viscosity of the polyimide varnish composition was measured at 25°C using a viscometer TV-25 manufactured by Toki Sangyo Co., Ltd.

(5) Contents of tertiary amines, pyridine derivatives, and impurities derived therefrom

The total content of tertiary amines, pyridine derivatives, and impurities derived therefrom from the polyimide varnish composition (hereinafter also referred to as "specific impurity content") is measured by gas chromatography (GC) and analyzed by the following method. Did.

(GC analysis conditions)

As a measuring device, the analysis was conducted using 7890A, Aglilent Technology, column DB-624 (length 30 m×inner diameter 0.25 mm, film thickness 1.4 μm).

On the other hand, the detection limit or less means that the specific impurity content with respect to the polyimide is 30 mass ppm or less.

[Example 1]

1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., hereinafter referred to as 1,3-BAC:trans ratio 30) as a diamine component in a reaction pot made of stainless steel having a 3-stage paddle stirring blade made of stainless steel, about 240L. %)) 5589g and 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Industrial Co., Ltd.) 12476g, γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) 61.44kg added as a reaction solvent, and added to the system The solution was obtained by stirring under a nitrogen atmosphere at a temperature of about 90°C. As a tetracarboxylic acid component, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (manufactured by Daikin Industries, Ltd.) 17333g, 3,3', 4,4'-biphenyltetracarboxylic dianhydride ( After adding 11466 g of Mitsubishi Chemical Co., Ltd. and 15000 g of γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as a reaction solvent, the temperature in the reaction system was raised to 180° C. over about 80 minutes. The distilled components were collected, and the reaction system temperature was maintained at 180°C and stirred for 5.25 hours to obtain a polyimide solution. Thereafter, the reaction system was cooled to 120°C to stop the reaction, and a total of 113,800 g of N,N-dimethylacetamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as a diluting solvent. The solution was stirred until uniform, and a polyimide varnish composition (A) having a solid content concentration of 16.5 mass% was obtained. The YI value of this polyimide varnish composition (A) was 6.3, the specific impurity content was below the detection limit, and the viscosity was 55.0 Pa·s.

Subsequently, a polyimide varnish composition (A) was applied on a glass substrate, and maintained at 60°C for 30 minutes and 100°C for 1 hour, and the solvent was volatilized to obtain a colorless and transparent primary dry film having self-supporting properties, Then, the film was fixed to a stainless frame, and dried at 280° C. under a nitrogen atmosphere for 2 hours to remove the solvent, thereby obtaining a film having a thickness of 73 μm. FT-IR analysis of the obtained film confirmed the disappearance of the raw material peaks and the appearance of peaks originating from the imide skeleton. The total light transmittance of this polyimide film was 90.4%, the YI value was 2.6, and the haze was 0.2.

[Example 2]

1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., 1,3-BAC:trans ratio 30%) in a reaction pot made of SUS made of stainless steel with a three-stage paddle stirring wing of about 240L. ) 5589g and 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Co., Ltd.) 12476g, γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) 61.44kg as a reaction solvent was added, and the temperature inside the system was about 90°C. , Stirred under a nitrogen atmosphere to obtain a solution. As a tetracarboxylic acid component, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (manufactured by Daikin Industries, Ltd.) 17333g, 3,3', 4,4'-biphenyltetracarboxylic dianhydride ( After adding 11466 g of Mitsubishi Chemical Co., Ltd. and 15000 g of γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as a reaction solvent, the temperature in the reaction system was raised to 180° C. over about 80 minutes. The distilled components were collected, and the reaction system temperature was maintained at 180°C and stirred for 4 hours to obtain a polyimide solution. Thereafter, the reaction temperature was cooled to 120°C to stop the reaction, and a total of 105,870 g of N,N-dimethylacetamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added. The solution was stirred until uniform, and a polyimide varnish composition (B) having a solid content concentration of 19.8% by mass was obtained. The YI value of this polyimide varnish composition (B) was 9.5, the specific impurity content was below the detection limit, and the viscosity was 47.7 Pa·s.

Subsequently, a polyimide varnish composition (B) was applied onto a glass substrate, and maintained at 60°C for 30 minutes and 100°C for 1 hour, and the solvent was volatilized to obtain a colorless and transparent primary dry film having self-supporting properties. Then, this film was fixed to a stainless frame, and dried at 280° C. under a nitrogen atmosphere for 2 hours to remove the solvent to obtain a film having a thickness of 80 μm. FT-IR analysis of the obtained film confirmed the disappearance of the raw material peaks and the appearance of peaks originating from the imide skeleton. The total light transmittance of this polyimide film was 90.3%, the YI value was 3.1, and the haze was 0.6.

[Comparative Example 1]

1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., 1,3-BAC:trans ratio 30%) in a reaction pot made of SUS made of stainless steel with a three-stage paddle stirring wing of about 240L. ) 5589g and 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Co., Ltd.) 12476g, γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) 61.44kg as a reaction solvent was added, and the temperature inside the system was about 90°C. , Stirred under a nitrogen atmosphere to obtain a solution. As a tetracarboxylic acid component, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (manufactured by Daikin Industries, Ltd.) 17333g, 3,3', 4,4'-biphenyltetracarboxylic dianhydride ( 11466 g of Mitsubishi Chemical Co., Ltd. and 15000 g of γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as a reaction solvent were added, and 394 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) as a catalyst was added, and the reaction system was added over about 80 minutes. The temperature was raised to 180°C. The distilled components were collected, and the reaction system temperature was maintained at 180°C and stirred for 9.5 hours to obtain a polyimide solution. Thereafter, the reaction system was cooled to 120°C to stop the reaction, and a total of 113,800 g of N,N-dimethylacetamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as a diluting solvent. The solution was stirred until uniform, and a polyimide varnish composition (C) having a solid content concentration of 18.5% by mass was obtained. The polyimide varnish composition (C) had a YI value of 56.1, a specific impurity content of 330 mass ppm, and a viscosity of 50.2 Pa·s.

Subsequently, the polyimide varnish composition (C) was applied onto a glass substrate, and maintained at 60°C for 30 minutes and 100°C for 1 hour, and a solvent was volatilized to obtain a primary dry film having self-supporting properties, and The film was fixed to a stainless frame and dried at 280° C. under a nitrogen atmosphere for 2 hours to remove the solvent to obtain a film having a thickness of 76 μm. FT-IR analysis of the obtained film confirmed the disappearance of the raw material peaks and the appearance of peaks originating from the imide skeleton. The total light transmittance of this polyimide film was 89.7%, the YI value was 5.8, and the haze was 0.4.

[Comparative Example 2]

1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., 1,3-BAC:trans ratio 30%) in a reaction pot made of SUS made of stainless steel with a three-stage paddle stirring wing of about 240L. ) 5589g and 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Industrial Co., Ltd.) 12476g, γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) 61.44kg as a reaction solvent was added, and the temperature inside the system was about 90°C. , Stirred under a nitrogen atmosphere to obtain a solution. As a tetracarboxylic acid component, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (manufactured by Daikin Industries, Ltd.) 17333g, 3,3', 4,4'-biphenyltetracarboxylic dianhydride ( 11466 g of Mitsubishi Chemical Co., Ltd. and 15000 g of γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as a reaction solvent were added, and 236 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) as a catalyst was added, and the reaction system was added over about 80 minutes. The temperature was raised to 180°C. The distilled components were collected, and the reaction system temperature was maintained at 180°C and stirred for 8 hours to obtain a polyimide solution. Thereafter, the reaction temperature was cooled to 120°C to stop the reaction, and a total of 113240 g of N,N-dimethylacetamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as a diluting solvent. The solution was stirred until uniform, and a polyimide varnish composition (D) having a solid content concentration of 18.7 mass% was obtained. The polyimide varnish composition (D) had a YI value of 36.1, a specific impurity content of 300 mass ppm, and a viscosity of 49.5 Pa·s.

Subsequently, the polyimide varnish composition (D) was applied on a glass substrate, and maintained at 60°C for 30 minutes and 100°C for 1 hour, and the solvent was volatilized to obtain a primary dry film having self-supporting properties, and The film was fixed to a stainless frame, and dried at 280° C. under a nitrogen atmosphere for 2 hours to remove the solvent, thereby obtaining a film having a thickness of 80 μm. FT-IR analysis of the obtained film confirmed the disappearance of the raw material peaks and the appearance of peaks originating from the imide skeleton. The total light transmittance of this polyimide film was 89.6%, the YI value was 5.6, and the haze was 0.5.

The symbol in the table is as follows.

6FDA: 4,4'-(hexafluoroisopropylidene) diphthalic anhydride [compound represented by formula (a-1)]

s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride [compound represented by formula (a-2-1)]

1,3-BAC: trans ratio 30%: 1,3-bis(aminomethyl)cyclohexane [cis:trans=70:30 (molar ratio) compound represented by formula (b-2)]

TFMB: 2,2'-bis(trifluoromethyl) benzidine [compound represented by formula (b-4)]

GBL: γ-butyrolactone

DMAc: N,N-dimethylacetamide

TEA: triethylamine

From Table 1, it is understood that the polyimide films having excellent colorless transparency can be formed from the viewpoints of low YI of the polyimide varnish compositions of Examples 1 and 2, low YI and haze of the polyimide film, and high total light transmittance. Can be. On the other hand, the polyimide varnish compositions of Comparative Examples 1 and 2 and the polyimide film had a high YI and could not make the colorless transparency of the polyimide film favorable.

Claims (17)

A polyimide varnish composition comprising a polyimide and an organic solvent,
This polyimide has a structural unit A derived from tetracarboxylic acid or a derivative thereof, and a structural unit B derived from diamine,
This structural unit A contains the structural unit (A-1) derived from the compound represented by the following formula (a-1),
With respect to the total amount of the polyimide varnish composition, at least one organic solvent selected from lactone-based solvents is contained at least 20% by mass,
The polyimide varnish composition having a YI of 20 or less measured in a cell of 23°C and an optical path length of 10 mm of this polyimide varnish composition.
[Formula 1]

According to claim 1,
A polyimide varnish composition, wherein the total content of tertiary amine, pyridine derivative, and impurities derived therefrom is 30 ppm by mass or less with respect to polyimide. The method according to claim 1 or 2,
The polyimide varnish composition, wherein the structural unit B comprises at least one member selected from the group consisting of a structural unit derived from an aliphatic diamine and a structural unit derived from an aromatic diamine. The method according to any one of claims 1 to 3,
A polyimide varnish composition, wherein the structural unit B includes a structural unit derived from an aliphatic diamine, and a structural unit derived from an aromatic diamine. The method of claim 3 or 4,
The structural unit derived from the said aliphatic diamine is a structural unit (B-1) derived from the compound represented by the following formula (b-1), and a structural unit derived from the compound represented by the following formula (b-2) (B A polyimide varnish composition comprising at least one member selected from the group consisting of -2) and a structural unit (B-3) derived from a compound represented by the following formula (b-3).
[Formula 2]

The method according to any one of claims 3 to 5,
The polyimide varnish composition, wherein the structural unit derived from the aromatic diamine includes a structural unit (B-4) derived from a compound represented by the following formula (b-4).
[Formula 3]

The method according to any one of claims 1 to 6,
The said structural unit A further contains the structural unit (A-2) derived from the compound represented by following formula (a-2), The polyimide varnish composition.
[Formula 4]

The method according to any one of claims 1 to 7,
The ratio of the structural unit (A-1) to the structural unit A is 30 mol% or more, a polyimide varnish composition. The method according to any one of claims 3 to 8,
The ratio of the structural unit derived from the aliphatic diamine to the structural unit B is 10 to 95 mol%, a polyimide varnish composition. The method according to any one of claims 3 to 9,
The ratio of the structural unit derived from the aromatic diamine to the structural unit B is 5 to 90 mol%, a polyimide varnish composition. The method according to any one of claims 1 to 10,
The polyimide varnish composition wherein the content of the amide solvent relative to the total amount of the polyimide varnish composition is 70% by mass or less. A polyimide film obtained from the polyimide varnish composition according to any one of claims 1 to 11. The method of claim 12,
The polyimide film whose YI of the polyimide film in thickness 80 micrometers is 3.5 or less, total light transmittance is 80% or more, and haze is 1.0% or less. Diamine component and 4,4'-(hexafluoroisopropylidene)diphthalic acid or a derivative thereof in the presence of at least one organic solvent selected from a lactone-based solvent, and in the absence of a catalyst and a dehydrating agent. As a method for producing a polyimide varnish composition containing a polyimide and an organic solvent by reacting a tetracarboxylic acid component, the content of the lactone-based solvent relative to the total amount of the polyimide varnish composition is 20% by mass or more, and this polyimide A method for producing a polyimide varnish composition, wherein the YI measured in a cell of 23° C., optical path length of 10 mm of the varnish composition is 20 or less. The method of claim 14,
Diamine component and 4,4'-(hexafluoroisopropylidene)diphthalic acid or a derivative thereof in the presence of at least one organic solvent selected from a lactone-based solvent, and in the absence of a catalyst and a dehydrating agent. A method for producing a polyimide varnish composition, wherein a polyimide varnish composition is obtained by reacting a tetracarboxylic acid component to obtain a polyimide solution, and mixing the obtained polyimide solution with a diluting solvent. The method of claim 15,
A method for producing a polyimide varnish composition, wherein the diluting solvent contains an amide solvent. The method according to any one of claims 14 to 16,
Method of producing a polyimide varnish composition, the reaction temperature is 170 ~ 190 ℃.