WO2022019226A1

WO2022019226A1 - Polyimide resin, polyimide varnish, and polyimide film

Info

Publication number: WO2022019226A1
Application number: PCT/JP2021/026768
Authority: WO
Inventors: 菜摘脇田; 重之廣瀬
Original assignee: 三菱瓦斯化学株式会社
Priority date: 2020-07-21
Filing date: 2021-07-16
Publication date: 2022-01-27
Also published as: TW202214747A; JPWO2022019226A1; CN116134072A; KR20230041690A

Abstract

A polyimide resin that has structural units A derived from tetracarboxylic acid dianhydride and structural units B derived from diamine, said structural units A containing structural units (A1) derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene acid dianhydride and structural units (A2) derived from aliphatic tetracarboxylic acid dianhydride, and said structural units B containing structural units (B1) derived from 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane.

Description

Polyimide resin, polyimide varnish and polyimide film

The present invention relates to a polyimide resin, a polyimide varnish and a polyimide film.

Polyimide resins are obtained from aromatic tetracarboxylic acid anhydrides and aromatic diamines and generally have excellent heat resistance, chemical resistance, mechanical properties and electrical properties due to molecular rigidity, resonance stabilization and strong chemical bonds. Therefore, it is widely used in the fields of molding materials, composite materials, electrical / electronic parts, optical materials, displays, aerospace, and the like.
In particular, the application to flexible devices is being studied by taking advantage of the fact that it is flexible with respect to glass materials that have been conventionally used for applications such as electric / electronic parts, optical materials, and displays.

For example, Patent Document 1 describes a tetracarboxylic dianhydride component containing an alicyclic tetracarboxylic dianhydride and a fluorine-containing aromatic for the purpose of improving heat resistance, polyimide, flexibility, and transparency. A composition for forming a flexible device substrate is disclosed, which comprises a polyimide which is a reaction product with a diamine component containing a diamine, and an organic solvent.

International Publication No. 2018/097143

In recent years, the application of polyimide resin to applications of displays and front plates that protect them has been advancing, and from the viewpoint of substituting glass materials that have been conventionally used, good mechanical strength, that is, high strength and high elastic modulus. Polyimide resin is required. However, the conventional high-strength polyimide resin has a problem that the flexibility is not sufficient and many of them are inferior in colorless transparency.
Recently, since it is also used as a display or protective plate for smartphones with a foldable structure, it is required to have higher strength and higher flexibility, and it is also necessary to have the property of recovering the shape after the polyimide film is deformed. There is.
Therefore, a polyimide resin having these properties has been desired.
That is, the problem to be solved by the present invention is a polyimide resin capable of forming a film having both mechanical properties and colorless transparency and having high strength and excellent deformation recovery, and both mechanical properties and colorless transparency. Further, it is an object of the present invention to provide a polyimide film having high strength and excellent deformation recovery property.

As a result of diligent studies by the inventors, they have found that a polyimide resin containing a combination of specific structural units can solve the above-mentioned problems, and have reached the present invention.

That is, the present invention relates to the following [1] to [8].
[1] A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine.
The structural unit A includes a structural unit (A1) derived from the compound represented by the following formula (a1) and a structural unit (A2) derived from the aliphatic tetracarboxylic dianhydride, and the structural unit B is the following formula. A polyimide resin containing a structural unit (B1) derived from the compound represented by (b1).

[2] The polyimide resin according to the above [1], wherein the structural unit (A2) is a structural unit derived from an alicyclic tetracarboxylic dianhydride.
[3] The structural unit (A2) is a structural unit (A2-1) derived from a compound represented by the following formula (a2-1) and a configuration derived from a compound represented by the following formula (a2-2). The above-mentioned [1] or [2], which is at least one selected from the group consisting of the unit (A2-2) and the structural unit (A2-3) derived from the compound represented by the following formula (a2-3). The polyimide resin described in.

[4] The polyimide resin according to any one of the above [1] to [3], wherein the ratio of the structural unit (B1) to the structural unit B is 30 mol% or more.
[5] The polyimide resin according to any one of the above [1] to [4], wherein the ratio of the structural unit (A1) to the structural unit A is 50 to 90 mol%.
[6] The structural unit (A2) is one of the above-mentioned [1] to [5], which is a structural unit (A2-2) derived from a compound represented by the following formula (a2-2). The polyimide resin described.

[7] A polyimide varnish in which the polyimide resin according to any one of the above [1] to [6] is dissolved in an organic solvent.
[8] A polyimide film containing the polyimide resin according to any one of the above [1] to [6].

According to the present invention, a polyimide resin capable of forming a film having both mechanical properties and colorless transparency and having high strength and excellent deformation recovery properties, a polyimide varnish containing the polyimide resin, and mechanical properties and colorless transparency. It is possible to provide a polyimide film having both high strength and excellent deformation recovery.

It is a conceptual diagram which shows the method of measuring the deformation recovery property of a polyimide film.

[Polyimide resin]
The polyimide resin of the present invention is a polyimide resin having a structural unit A derived from tetracarboxylic acid dianhydride and a structural unit B derived from diamine, and the structural unit A is represented by the following formula (a1). Containing a structural unit (A1) derived from a compound and a structural unit (A2) derived from an aliphatic tetracarboxylic acid dianhydride, the structural unit B is a structural unit derived from a compound represented by the following formula (b1). (B1) and is included.

Hereinafter, the polyimide resin of the present invention will be described.

[Constructive unit A]
The structural unit A contained in the polyimide of the present invention is a structural unit derived from the tetracarboxylic dianhydride in the polyimide resin.
The structural unit A includes a structural unit (A1) derived from the compound represented by the formula (a1) and a structural unit (A2) derived from the aliphatic tetracarboxylic dianhydride.

The compound represented by the formula (a1) is 9,9-bis (3,4-dicarboxyphenyl) fluorenic acid dianhydride (BPAF).
When the structural unit A includes the structural unit (A1), the mechanical strength of the obtained polyimide resin is improved.

The structural unit (A2) is a structural unit derived from the aliphatic tetracarboxylic acid dianhydride, and the structural unit (A2) preferably contains a structural unit derived from the alicyclic tetracarboxylic acid dianhydride, and more. It preferably contains a structural unit derived from a tetracarboxylic acid dianhydride having an alicyclic having 4 to 25 carbon atoms. By containing a structural unit derived from a tetracarboxylic dianhydride having an alicyclic ring, deformation recovery and colorless transparency are improved while maintaining mechanical strength.
In the present specification, the aliphatic tetracarboxylic acid dianhydride means a tetracarboxylic acid dianhydride containing no aromatic ring, and the alicyclic tetracarboxylic acid dianhydride means an aliphatic tetracarboxylic acid dianhydride. Among the substances, it means a tetracarboxylic acid dianhydride containing one or more alicyclics.
Here, the "alicyclic" refers to a cyclic hydrocarbon structure excluding an aromatic ring among the structures in which carbon atoms are cyclically bonded, and the number of carbon atoms in the alicyclic ring refers to the number of carbons constituting the ring.

Specific examples of the alicyclic tetracarboxylic acid dianhydride include 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, and norbornan-2. -Spiro-α-cyclopentanone-α'-Spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid dianhydride, bicyclo [2.2.2] octa-7 -En-2,3,5,6-tetracarboxylic acid dianhydride, dicyclohexyltetracarboxylic acid dianhydride, position isomers thereof and the like can be mentioned.
Specific examples of the aliphatic tetracarboxylic acid dianhydride other than the alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-butanetetracarboxylic acid dianhydride.

Among these, the structural unit (A2) derived from the aliphatic tetracarboxylic dianhydride includes the structural unit (A2-1) derived from the compound represented by the following formula (a2-1) and the following formula (A2-1). At least one selected from the structural unit (A2-2) derived from the compound represented by a2-2) and the structural unit (A2-3) derived from the compound represented by the following formula (a2-3). It is preferably contained, and more preferably it contains a structural unit (A2-2) derived from a compound represented by the following formula (a2-2). The structural unit (A2) derived from the aliphatic tetracarboxylic acid dianhydride is a structural unit (A2-1) derived from the compound represented by the following formula (a2-1), and the following formula (a2-2). It is preferably at least one selected from the structural unit (A2-2) derived from the compound represented by the above and the structural unit (A2-3) derived from the compound represented by the following formula (a2-3). , It is more preferable that it is a structural unit (A2-2) derived from a compound represented by the following formula (a2-2).

The compound represented by the formula (a2-1) is 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA).
The compound represented by the formula (a2-2) is 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA).
The compound represented by the above formula (a2-3) is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'', 6,6''-tetra. It is a carboxylic dianhydride (CpODA).
When the structural unit A includes the structural unit (A2), the deformation recovery property and the colorless transparency are improved while maintaining the mechanical strength.
As described above, since the structural unit A derived from tetracarboxylic acid dianhydride has the structural units (A1) and (A2), the polyimide resin and the polyimide film of the present invention have both mechanical properties and colorless transparency. However, the reason why it is excellent in deformation recovery while having high strength is not clear, but it is considered to be derived from the rigidity of the fluorene group and the degree of freedom of the aliphatic compound.

The ratio of the constituent unit (A1) to the constituent unit A is preferably 30 to 90 mol%, more preferably 40 to 90 mol%, still more preferably 50 to 90 mol%, still more preferably 50. ~ 80 mol%.
The ratio of the constituent unit (A2) to the constituent unit A is preferably 10 to 70 mol%, more preferably 10 to 60 mol%, still more preferably 10 to 50 mol%, still more preferably 20. ~ 50 mol%.

The total ratio of the structural unit (A1) and the structural unit (A2) in the structural unit A is preferably 50 mol% or more, more preferably 70 mol% or more, and further preferably 90 mol% or more. The upper limit of the ratio of the total of the constituent units (A1) and the constituent units (A2) is not particularly limited, and is 100 mol% or less. The constituent unit A may be composed of only the constituent unit (A1) and the constituent unit (A2).

The molar ratio [(A1) / (A2)] of the structural unit (A1) and the structural unit (A2) in the structural unit A is preferably 20/80 from the viewpoint of improving mechanical properties, colorless transparency and deformation recovery. It is ~ 90/10, more preferably 30/70 to 90/10, further preferably 40/60 to 80/20, and even more preferably 50/50 to 70/30.
Especially from the viewpoint of improving the deformation recovery at high temperature, it is preferably 40/60 to 80/20, more preferably 40/60 to 70/30, and further preferably 40/60 to 60/40. Is.

The polyimide resin of the present invention contains a constituent unit derived from a tetracarboxylic dianhydride other than the constituent unit (A1) and the constituent unit (A2) in the constituent unit A as long as the effect of the present invention is not impaired. You may.
The tetracarboxylic acid dianhydride that gives a structural unit other than the structural unit (A1) and the structural unit (A2) is not particularly limited, but is pyromellitic anhydride, 2,3,5,6-toluenetetracarboxylic dianhydride. Examples thereof include aromatic tetracarboxylic acid dianhydrides such as 1,4,5,8-naphthalenetetracarboxylic acid dianhydride. These can be used alone or in combination of two or more.

In the present specification, the aromatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing one or more aromatic rings.

[Structural unit B]
The structural unit B contained in the polyimide of the present invention is a structural unit derived from diamine.
The structural unit B includes a structural unit (B1) derived from the compound represented by the following formula (b1).

The compound represented by the formula (b1) is 2,2'-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane (HFBAPP).
When the structural unit B includes the structural unit (B1), the mechanical strength can be improved while maintaining the colorless transparency of the obtained polyimide resin.

The ratio of the constituent unit (B1) to the constituent unit B is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably 50 mol% or more. Is.
In particular, from the viewpoint of improving the elongation of the obtained polyimide film, it is more preferably 70 mol% or more, still more preferably 90 mol% or more.
Further, the upper limit of the ratio of the constituent unit (B1) is not particularly limited, and is 100 mol% or less. The structural unit B may be composed of only the structural unit (B1).

The polyimide resin of the present invention contains a diamine other than the compound represented by the general formula (b1) as a structural unit other than the structural unit (B1) in the structural unit B as long as the effect of the present invention is not impaired. It may contain the building blocks from which it is derived.
The diamine other than the compound represented by the above general formula (b1) is not particularly limited, but is limited to 3,5-diaminobenzoic acid (3,5-DABA) and bis [4- (3-aminophenoxy) phenyl] sulfone. (BAPS-M), 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA), 1,4-phenylenediamine, p-xylylene diamine, 1,5-diaminonaphthalene, 2 , 2'-dimethylbiphenyl-4,4'-diamine, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, 1,4-bis [2- (4-aminophenyl) )-2-propyl] benzene, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4'-diaminobenzanilide, 1- (4-aminophenyl) -2,3-dihydro-1,3 , 3-trimethyl-1H-inden-5-amine, α, α'-bis (4-aminophenyl) -1,4-diisopropylbenzene, N, N'-bis (4-aminophenyl) terephthalamide, 2, Aromatic diamines such as 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and 1,4-bis (4-aminophenoxy) benzene; 1,3-bis (aminomethyl) cyclohexane, and 1, Examples thereof include alicyclic diamines such as 4-bis (aminomethyl) cyclohexane; aliphatic diamines such as ethylenediamine and hexamethylenediamine; and modified silicone diamines. These can be used alone or in combination of two or more.
Among these, from the viewpoint of high strength and improvement of deformation recovery at high temperature, 3,5-diaminobenzoic acid (3,5-DABA) and bis [4- (3-aminophenoxy) phenyl] sulfone ( At least one selected from the group consisting of BAPS-M) and 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (6FODA) is preferred.

In the present specification, the aromatic diamine means a diamine containing one or more aromatic rings, the aliphatic diamine means a diamine not containing an aromatic ring, and the aliphatic diamine means an aliphatic diamine. , Means a diamine containing one or more alicyclics.

[Characteristics of polyimide resin, etc.]
The number average molecular weight of the polyimide resin of the present invention is preferably 5,000 to 100,000 from the viewpoint of the mechanical strength of the obtained polyimide film. The number average molecular weight of the polyimide resin can be measured by gel filtration chromatography or the like.

The polyimide resin of the present invention may be further mixed with various additives as long as the effects of the present invention are not impaired. Examples of the additive include antioxidants, light stabilizers, surfactants, flame retardants, plasticizers, polymer compounds other than the polyimide resin, and the like.
Examples of the polymer compound include polyimides other than the polyimide resin of the present invention, polyesters such as polycarbonate, polystyrene, polyamide, polyamideimide and polyethylene terephthalate, polyethersulfone, polycarboxylic acid, polyacetylene, polyphenylene ether, polysulfone, polybutylene, polypropylene and poly. Examples include acrylamide, polyvinyl chloride and the like.

[Manufacturing method of polyimide resin]
The polyimide resin of the present invention is obtained by reacting a tetracarboxylic acid component containing the above-mentioned compound giving the structural unit (A1) and the compound giving (A2) with a diamine component containing the compound giving the structural unit (B1). Can be manufactured.

Examples of the compound giving the structural unit (A1) include the compound represented by the formula (a1), but the compound is not limited to this, and may be a derivative thereof as long as the same structural unit is given. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a1) and an alkyl ester of the tetracarboxylic acid. As the compound giving the structural unit (A1), the compound represented by the formula (a1) (that is, dianhydride) is preferable.
Similarly, examples of the compound giving the structural unit (A2) include an aliphatic tetracarboxylic dianhydride, preferably an alicyclic tetracarboxylic dianhydride, and more preferably a formula (a2-1) and a formula (a2-1). Examples thereof include the compound represented by a2-2) or the formula (a2-3), but the compound is not limited to this, and may be a derivative thereof as long as the same structural unit is given. Examples of the derivative of the compound represented by the formula (a2-1), the formula (a2-2) or the formula (a2-3) include the formula (a2-1), the formula (a2-2) or the formula (a2-3). Examples thereof include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by and an alkyl ester of the tetracarboxylic acid. As the compound giving the structural unit (A2), a compound represented by the formula (a2-1), the formula (a2-2) or the formula (a2-3) (that is, a dianhydride) is preferable.

The tetracarboxylic acid component contains, preferably 30 to 90 mol%, more preferably 40 to 90 mol%, still more preferably 50 to 90 mol%, and even more preferably 50, the compound giving the structural unit (A1). Contains ~ 80 mol%.
The tetracarboxylic acid component contains, preferably 10 to 70 mol%, more preferably 10 to 60 mol%, still more preferably 10 to 50 mol%, and even more preferably 20 to the compound giving the structural unit (A2). Contains ~ 50 mol%.

The total content ratio of the compound giving the structural unit (A1) and the compound giving the structural unit (A2) is preferably 50 mol% or more, more preferably 70 mol% or more, in the total tetracarboxylic acid component. More preferably, it is 90 mol% or more. The upper limit of the total content ratio of the compound giving the structural unit (A1) and the compound giving the structural unit (A2) is not particularly limited and is 100 mol% or less. The tetracarboxylic dian component may consist only of a compound that gives a constituent unit (A1) and a compound that gives a constituent unit (A2).

The molar ratio [(A1) / (A2)] of the compound giving the constituent unit (A1) to the compound giving the constituent unit (A2) in the tetracarboxylic acid component improves mechanical properties, colorless transparency and deformation recovery. From the viewpoint, it is preferably 20/80 to 90/10, more preferably 30/70 to 90/10, still more preferably 40/60 to 80/20, and even more preferably 50/50 to 70. / 30.
Especially from the viewpoint of improving the deformation recovery at high temperature, it is preferably 40/60 to 80/20, more preferably 40/60 to 70/30, and further preferably 40/60 to 60/40. Is.

The tetracarboxylic acid component may contain a compound other than the compound giving the structural unit (A1) and the compound giving the structural unit (A2), and the compound includes the above-mentioned aromatic tetracarboxylic dianhydride and derivatives thereof. (Tetracarboxylic acid, alkyl ester of tetracarboxylic acid, etc.) can be mentioned.
The compound arbitrarily contained in the tetracarboxylic acid component (that is, a compound other than the compound giving the structural unit (A1) and the structural unit (A2)) may be one kind or two or more kinds.

Examples of the compound giving the structural unit (B1) include the compound represented by the formula (b1), but the compound is not limited to this, and may be a derivative thereof as long as the same structural unit is given. Examples of the derivative include diisocyanates corresponding to the diamine represented by the formula (b1). As the compound that gives the structural unit (B1), the compound represented by the formula (b1) (that is, a diamine) is preferable.

The diamine component contains the compound giving the constituent unit (B1) in an amount of preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably 50 mol% or more. Including the above. In particular, from the viewpoint of improving the elongation of the obtained polyimide film, it is more preferably contained in an amount of 70 mol% or more, and further preferably contained in an amount of 90 mol% or more. Further, the upper limit of the ratio of the compound giving the structural unit (B1) is not particularly limited, and is 100 mol% or less. The diamine component may consist only of the compound giving the structural unit (B1).

The diamine component may contain a compound other than the compound giving the structural unit (B1), and the compound includes the above-mentioned aromatic diamine, alicyclic diamine, aliphatic diamine, modified silicone diamine, and derivatives thereof (diisocyanate). Etc.).
The compound arbitrarily contained in the diamine component (that is, a compound other than the compound giving the structural unit (B1)) may be one kind or two or more kinds.

When producing the polyimide resin according to the present invention, the charging amount ratio of the tetracarboxylic acid component and the diamine component is preferably 0.9 to 1.1 mol of the diamine component with respect to 1 mol of the tetracarboxylic acid component. ..

When producing the polyimide resin of the present invention, an end-capping agent may be used in addition to the tetracarboxylic acid component and the diamine component. As the terminal encapsulant, monoamines or dicarboxylic acids are preferable. The amount of the terminal encapsulant to be introduced is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.06 mol, based on 1 mol of the tetracarboxylic acid component. Preferred monoamine terminal encapsulants include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine and 3-ethyl. Benzylamine, aniline, 3-methylaniline, 4-methylaniline and the like can be mentioned. Of these, benzylamine and aniline are more preferable. As the dicarboxylic acid terminal encapsulant, dicarboxylic acids are preferable, and a part thereof may be ring-closed. Preferred dicarboxylic acids include phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid and cyclopentane. Examples thereof include -1,2-dicarboxylic acid and 4-cyclohexene-1,2-dicarboxylic acid. Of these, phthalic acid and phthalic anhydride are more preferable.

The method for reacting the above-mentioned tetracarboxylic acid component and the diamine component is not particularly limited, and a known method can be used.
As a specific reaction method, (1) a tetracarboxylic acid component, a diamine component, and a reaction solvent are charged in a reactor, stirred at 10 to 110 ° C. for 0.5 to 30 hours, and then heated to imidize. Method of carrying out the reaction, (2) The diamine component and the reaction solvent are charged into a reactor and dissolved, then the tetracarboxylic acid component is charged, and if necessary, the mixture is stirred at 10 to 110 ° C. for 0.5 to 30 hours, and then. Examples thereof include a method of carrying out an imidization reaction by raising the temperature to (3) a method of charging a tetracarboxylic acid component, a diamine component and a reaction solvent into a reactor and immediately raising the temperature to carry out the imidization reaction.

The reaction solvent used for producing the polyimide resin may be any one that does not inhibit the imidization reaction and can dissolve the produced polyimide resin. For example, an aprotic solvent, a phenol solvent, an ether solvent, a carbonate solvent and the like can be mentioned.

Specific examples of the aprotonic solvent include N, N-dimethylisobutylamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethyl. Amide solvents such as imidazolidinone and tetramethylurea, lactone solvents such as γ-butyrolactone and γ-valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphintriamide, dimethyl sulfone, Sulfur-containing solvents such as dimethyl sulfoxide and sulfolane, ketone solvents such as acetone, cyclohexanone and methylcyclohexane, amine solvents such as picolin and pyridine, ester solvents such as acetic acid (2-methoxy-1-methylethyl), etc. Can be mentioned.

Specific examples of the phenolic 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 can be mentioned.
Specific examples of the ether solvent include 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, and bis [2- (2-methoxyethoxy) ethyl]. Examples include ether, tetrahydrofuran, 1,4-dioxane and the like.
Specific examples of the carbonate solvent include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate and the like.
Among the above reaction solvents, an amide solvent or a lactone solvent is preferable. Further, the above reaction solvent may be used alone or in combination of two or more.

In the imidization 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 degree of polymerization and the imidization rate can be further increased.

In the above imidization reaction, a known imidization catalyst can be used. Examples of the imidization catalyst include a base catalyst or an acid catalyst.
Base catalysts include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, imidazole, N, N-dimethylaniline. , N, N-diethylaniline and the like, organic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogencarbonate, sodium hydrogencarbonate and the like.
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, paratoluenesulfonic acid, naphthalenesulfonic acid and the like. Can be mentioned. The above imidization catalyst may be used alone or in combination of two or more.
Of the above, from the viewpoint of handleability, it is preferable to use a base catalyst, more preferably an organic base catalyst, and even more preferably triethylamine.

When the above catalyst is used, the temperature of the imidization reaction is preferably 120 to 250 ° C., more preferably 160 to 190 ° C., still more preferably 180 to 190 ° C. from the viewpoint of suppressing the reaction rate and gelation. be. The reaction time is preferably 0.5 to 10 hours after the start of distillation of the produced water.
The temperature of the imidization reaction when no catalyst is used is preferably 200 to 350 ° C.

[Polyimide varnish]
The polyimide varnish of the present invention is obtained by dissolving the polyimide resin of the present invention in an organic solvent. That is, the polyimide varnish of the present invention contains the polyimide resin of the present invention and an organic solvent, and the polyimide resin is dissolved in the organic solvent.
The organic solvent may be any one that dissolves the polyimide resin, and is not particularly limited, but it is preferable to use the above-mentioned compounds alone or in combination of two or more as the reaction solvent used for producing the polyimide resin.
The polyimide varnish of the present invention preferably contains 5 to 60% by mass of the polyimide resin of the present invention, and more preferably 5 to 45% by mass. The viscosity of the polyimide varnish is preferably 0.1 to 200 Pa · s, more preferably 0.5 to 150 Pa · s.

[Polyimide film]
The polyimide film of the present invention contains the above-mentioned polyimide resin. Further, the polyimide film of the present invention is preferably made of the above-mentioned polyimide resin.
That is, it has a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine, and the structural unit A is a structural unit (A1) derived from the compound represented by the formula (a1). A polyimide resin containing a structural unit (A2) derived from an aliphatic tetracarboxylic dianhydride, wherein the structural unit B contains a structural unit (B1) derived from the compound represented by the formula (b1).
By containing such a polyimide resin, the polyimide film of the present invention has both mechanical properties and colorless transparency, and is excellent in deformation recovery while having high strength.

The method for producing the polyimide film of the present invention is not particularly limited, and a known method can be used. For example, a solution containing the polyimide resin of the present invention or a solution containing the solution containing the polyimide resin of the present invention and the various additives described above is applied onto a smooth support such as a glass plate, a metal plate, or plastic. Alternatively, a method of removing a solvent component such as an organic solvent contained in the solution after molding into a film can be mentioned.

The solution containing the polyimide resin may be the polyimide resin solution itself obtained by the polymerization method. Further, at least one selected from the compounds exemplified above as a solvent for dissolving the polyimide resin in the polyimide resin solution may be mixed. By adjusting the solid content concentration and viscosity of the solution containing the polyimide resin as described above, the thickness of the polyimide film of the present invention can be easily controlled.

If necessary, a mold release agent may be applied to the surface of the support. The following method is preferable as a method of applying the polyimide resin or a solution containing the polyimide resin composition to the support and then heating to evaporate the solvent component. That is, after evaporating the solvent at a temperature of 120 ° C. or lower to form a self-supporting film, the self-supporting film was peeled off from the support, the end portion of the self-supporting film was fixed, and the solvent component used was used. It is preferable to produce a polyimide film by drying at a temperature equal to or higher than the boiling point and 350 ° C. or lower. Further, it is preferable to dry in a nitrogen atmosphere. The pressure in the dry atmosphere may be reduced pressure, normal pressure, or pressurized pressure.

The thickness of the polyimide film of the present invention can be appropriately selected depending on the intended use and the like, but is preferably in the range of 1 to 250 μm, more preferably 5 to 100 μm, and further preferably 10 to 80 μm. When the thickness is 1 to 250 μm, it can be practically used as a self-supporting film.

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

The present invention will be specifically described below with reference to Examples. However, the present invention is not limited to these examples.

The physical characteristics of the polyimide films obtained in the following Examples and Comparative Examples were measured by the methods shown below.
(1) Film thickness The film thickness was measured using a micrometer manufactured by Mitutoyo Co., Ltd.
(2) Tensile strength and tensile elastic modulus were measured in accordance with JIS K7127 using a tensile tester "Strograph VG1E" manufactured by Toyo Seiki Co., Ltd.
(3) Tensile breaking elongation rate The tensile breaking elongation rate was measured by a tensile test (measurement of elongation rate) in accordance with JIS K7127. The test piece used had a width of 10 mm and a thickness of 10 to 70 μm.
(4) Total light transmittance (evaluation of transparency)
The measurement was carried out in accordance with ASTM E313-05, using a color and turbidity simultaneous measuring instrument "COH7700" manufactured by Nippon Denshoku Kogyo Co., Ltd.
(5) Yellow index (YI) (evaluation of colorlessness)
The measurement was carried out in accordance with ASTM E313-05, using a color and turbidity simultaneous measuring instrument "COH7700" manufactured by Nippon Denshoku Kogyo Co., Ltd.
(5) Deformation recovery property As shown in FIG. 1A, the polyimide film 1 cut into a width of 10 mm and a length of 100 mm was fixed at R = 3 mm with a jig, and under the conditions of 65 ° C. and 90% relative humidity. Alternatively, it was allowed to stand at 70 ° C. under dry conditions for 24 hours or 100 hours. Then, the jig was removed at 23 ° C. and a relative humidity of 50%, and after allowing the film to stand for 170 hours, the deformation recovery was evaluated by measuring the angle θ shown in FIG. 1 (b). The smaller the measured angle, the better the deformation recovery, and the smaller the value, the better.

[Example 1]
A 300 mL five-necked round-bottom flask equipped with a stainless half-moon stirring blade, a nitrogen inlet tube, a Dean-Stark apparatus with a cooling tube, a thermometer, and a glass end cap, and 2,2'-bis as a diamine component. 4- (4-Aminophenoxy) phenyl] Hexafluoropropane (manufactured by Seika Co., Ltd., hereinafter HFBAPP) 27.66 g (0.053 mol), γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd., hereinafter GBL) 44. 8 g and 2.70 g of triethylamine (manufactured by Kanto Chemical Co., Ltd., hereinafter TEA) were added as an imidization catalyst, and the mixture was stirred at a system temperature of 70 ° C. and a nitrogen atmosphere at a rotation speed of 150 rpm to obtain a solution. To this, 12.23 g (0.027 mol) of 9,9-bis (3,4-dicarboxyphenyl) fluorenic acid dianhydride (manufactured by JFE Chemical Co., Ltd., hereinafter BPAF) as a tetracarboxylic acid component and 1,2,2, After adding 5.98 g (0.027 mol) of 4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd., hereinafter HPMDA) and 24.1 g of GBL in a batch, heat with a mantle heater to obtain about. The temperature inside the reaction system was raised to 190 ° C. over 20 minutes. A polyimide solution was obtained by collecting the components to be distilled off, maintaining the temperature inside the reaction system at 190 ° C., and refluxing for 2 hours while adjusting the rotation speed according to the increase in viscosity. After that, when the temperature inside the reaction system is cooled to 120 ° C., N, N-dimethylacetamide (manufactured by Mitsubishi Gas Chemical Company, Inc., hereinafter DMAc) is added so as to have a predetermined solid content concentration, and the mixture is further stirred for about 3 hours to make it uniform. A polyimide varnish (A) having a solid content concentration of 20.0% by mass was obtained.

Subsequently, the polyimide varnish (A) is applied onto a PET substrate, held at 60 ° C. for 20 minutes, 80 ° C. for 20 minutes, and 100 ° C. for 30 minutes to volatilize the solvent to provide self-supporting transparent primary. A dried film was obtained, and the film was further fixed to a stainless steel frame and dried at 220 ° C. in an air atmosphere for 20 minutes to remove the solvent to obtain a polyimide film. Table 1 shows the measurement results and evaluation results of the physical properties.

[Example 2]
The amount of HFBAPP is set to 24.25 g (0.047 mol), and 1.78 g (0.012 mol) of 3,5-diaminobenzoic acid (manufactured by Nippon Junyaku Ryohin Co., Ltd., hereinafter 3,5-DABA) is added. The same method as in Example 1 except that the amount of TEA was changed to 0.296 g, the amount of BPAF was changed to 13.40 g (0.029 mol), and the amount of HPMDA was changed to 6.55 g (0.029 mol). Obtained a polyimide varnish (B) having a solid content concentration of 15.0% by mass. Using the obtained polyimide varnish (B), a polyimide film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Example 3]
The amount of HFBAPP is 14.58 g (0.028 mol), and 12.16 g (0.028 mol) of bis [4- (3-aminophenoxy) phenyl] sulfone (manufactured by Seika Co., Ltd., hereinafter BAPS-M) is added. , The same as in Example 1 except that the amount of TEA was changed to 0.296 g, the amount of BPAF was changed to 12.89 g (0.028 mol), and the amount of HPMDA was changed to 6.31 g (0.028 mol). A polyimide varnish (C) having a solid content concentration of 18.5% by mass was obtained by the above method. Using the obtained polyimide varnish (C), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Example 4]
The amount of HFBAPP is 19.15 g (0.037 mol), and 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether (ChinaTech Chemical (Taijin) Co., Ltd., hereinafter 6FODA). 12.42 g (0.037 mol) was added, the amount of TEA was changed to 0.296 g, the amount of BPAF was 16.93 g (0.037 mol), and the amount of HPMDA was 8.28 g (0.037 mol). A polyimide varnish (D) having a solid content concentration of 18.5% by mass was obtained by the same method as in Example 1 except that the solid content was changed to 18.5% by mass. Using the obtained polyimide varnish (D), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Example 5]
The amount of HFBAPP is 12.08 g (0.023 mol), the amount of 6FODA is 18.28 g (0.054 mol), the amount of BPAF is 17.80 g (0.039 mol), and the amount of HPMDA is 8.70 g (. A polyimide varnish (E) having a solid content concentration of 18.5% by mass was obtained by the same method as in Example 4 except that the content was changed to 0.039 mol). Using the obtained polyimide varnish (E), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Example 6]
The amount of HFBAPP is 18.19 g (0.035 mol), the amount of 6FODA is 11.79 g (0.035 mol), the amount of BPAF is 22.51 g (0.049 mol), and the amount of HPMDA is 4.72 g (. A polyimide varnish (F) having a solid content concentration of 18.5% by mass was obtained by the same method as in Example 4 except that the content was changed to 0.021 mol). Using the obtained polyimide varnish (F), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Example 7]
The amount of HFBAPP was changed to 33.49 g (0.065 mol), the amount of BPAF was changed to 14.81 g (0.032 mol), and Norbornane-2-spiro-α-cyclopentanone-α was not used. Add 12.42 g (0.032 mol) of'-spiro-2''-norbornane-5,5'', 6,6''-tetracarboxylic acid dianhydride (manufactured by JXTG Energy Co., Ltd., hereinafter CpODA). A polyimide varnish (G) having a solid content concentration of 20.0% by mass was obtained by the same method as in Example 1. Using the obtained polyimide varnish (G), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Comparative Example 1]
Except that the amount of HFBAPP was changed to 30.52 g (0.059 mol), the amount of TEA was changed to 0.298 g, the amount of BPAF was changed to 26.98 g (0.059 mol), and HPMDA was not used. A polyimide varnish (H) having a solid content concentration of 18.5% by mass was obtained by the same method as in Example 1. Using the obtained polyimide varnish (H), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Comparative Example 2]
The amount of HFBAPP is 39.23 g (0.076 mol), the amount of 3,5-DABA is 2.88 g (0.019 mol), and the amount of HPMDA is 21.20 g (0.095 mol) without using BPAF. A polyimide varnish was produced by the same method as in Example 2 except that the solid content concentration was changed to (I), and a polyimide varnish (I) having a solid content concentration of 20% by mass was obtained. Using the obtained polyimide varnish (I), a film was obtained by the same method as in Example 1.

[Comparative Example 3]
Without using HFBAPP, 29.81 g (0.093 mol) of 2,2'-bis (trifluoromethyl) benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd., hereinafter TFMB) was used, and the amount of TEA was 0.471 g. By the same method as in Example 1, the solid content concentration was 20. 0% by mass of polyimide varnish (J) was obtained. Using the obtained polyimide varnish (J), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Comparative Example 4]
The amount of HFBAPP was changed to 29.96 g (0.058 mol), and 1,4-bis (aminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemicals Co., Ltd., hereinafter 1,4-BACT) was 8.22 g (0.058 mol). Mole) In addition, a polyimide varnish having a solid content concentration of 20.0% by mass by the same method as in Example 1 except that the amount of HPMDA was changed to 25.91 g (0.116 mol) without using BPAF. K) was obtained. Using the obtained polyimide varnish (K), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

[Comparative Example 5]
The amount of HFBAPP was set to 24.64 g (0.048 mol), the amount of TEA was changed to 0.481 g, and 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (Wakayama Seika Kogyo Co., Ltd.) The same method as in Example 1 except that 17.41 g (0.048 mol) of DABPAF (hereinafter referred to as DABPAF) manufactured by the company was added, and the amount of HPMDA was changed to 21.31 g (0.095 mol) without using BPAF. Obtained a polyimide varnish (L) having a solid content concentration of 20.0% by mass. Using the obtained polyimide varnish (L), a film was obtained by the same method as in Example 1. Table 1 shows the measurement results and evaluation results of the physical properties.

From Table 1, it can be seen that the polyimide films of Examples 1 to 7 have both mechanical properties and colorless transparency, and are excellent in deformation recovery under both high humidity conditions and dry conditions while having high strength. ..

Claims

A polyimide resin having a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine.
The structural unit A includes a structural unit (A1) derived from the compound represented by the following formula (a1) and a structural unit (A2) derived from the aliphatic tetracarboxylic dianhydride, and the structural unit B is the following formula. A polyimide resin containing a structural unit (B1) derived from the compound represented by (b1).
The polyimide resin according to claim 1, wherein the structural unit (A2) is a structural unit derived from an alicyclic tetracarboxylic dianhydride.
The structural unit (A2) is a structural unit (A2-1) derived from a compound represented by the following formula (a2-1), and a structural unit (A2) derived from a compound represented by the following formula (a2-2). -2) The polyimide resin according to claim 1 or 2, which is at least one selected from the group consisting of the structural unit (A2-3) derived from the compound represented by the following formula (a2-3).
The polyimide resin according to any one of claims 1 to 3, wherein the ratio of the structural unit (B1) to the structural unit B is 30 mol% or more.
The polyimide resin according to any one of claims 1 to 4, wherein the ratio of the structural unit (A1) to the structural unit A is 50 to 90 mol%.
The polyimide resin according to any one of claims 1 to 5, wherein the structural unit (A2) is a structural unit (A2-2) derived from a compound represented by the following formula (a2-2).
A polyimide varnish in which the polyimide resin according to any one of claims 1 to 6 is dissolved in an organic solvent.
A polyimide film containing the polyimide resin according to any one of claims 1 to 6.