TWI784056B - Polyimide resin, polyimide varnish and polyimide film - Google Patents

Abstract

This invention provides a polyimide resin comprising a constituting unit A derived from a tetracarboxylic acid dianhydride and a constituting unit B derived from a diamine, wherein the constituting unit A contains a constituting unit (A-1) derived from a compound represented by the following formula (a-1) and a constituting unit (A-2) derived from a compound represented by the following formula (a-2), and the constituting unit B contains a constituting unit (B-1) derived from a compound represented by the following formula (b-1) and a constituting unit (B-2) derived from a compound represented by the following formula (b-2).

Description

Polyimide resin, polyimide varnish and polyimide film

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

Polyimide resin, because of its excellent mechanical properties and heat resistance, has been studied for its various applications in the fields of electrical and electronic parts. For example, in order to reduce the weight or flexibility of the device, it is desired to replace the glass substrate used in image display devices such as liquid crystal displays or OLED displays with plastic substrates, and there are also people who are working on polyimide resins suitable for this plastic material. Research. Transparency is also required for the polyimide resin used in this way, and further, high dimensional stability to heat (that is, a low linear thermal expansion coefficient) is required so that it can cope with the manufacturing steps of image display devices. High temperature process.

As for the polyimide resin having a low coefficient of linear thermal expansion, for example, it is described in Patent Document 1 that a first tetracarboxylic acid component such as pyromellitic anhydride, 3,3',4,4'-bis A polyimide resin synthesized from a second tetracarboxylic acid component such as phenylsulfone tetracarboxylic acid dianhydride, and a diamine component of a ditoluidine skeleton, is described in Patent Document 2 as a polyimide resin composed of a benzoxazolyl-containing diamine. Polyimide resin synthesized from amine compound and aromatic tetracarboxylic dianhydride.

In addition, in recent years, in the field of microelectronics, in terms of the method of peeling the support body and the resin film from the support body laminated with the resin film, it is called laser lift-off (Laser Lift-off, LLO). ) laser lift-off processing is attracting attention. Therefore, in order for the polyimide film to be able to cope with the laser peeling process, laser peelability is also required for the polyimide film. In order to be able to cope with the exfoliation process performed by the XeCl excimer laser with a wavelength of 308nm, it is required that the polyimide film has excellent characteristics of absorbing light with a wavelength of 308nm (that is, the light transmittance at a wavelength of 308nm is small). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-053336 [Patent Document 2] Japanese Patent Laid-Open No. 2015-093915

[Problem to be Solved by the Invention]

Generally speaking, polyimide resins are excellent in mechanical properties and heat resistance, but in order to improve transparency, further improve thermal dimensional stability and laser peelability, the structure of polyimide resins is changed Finally, as a result, there is a possibility of impairing these properties, and the development of a polyimide resin with a good balance of mechanical properties, heat resistance, transparency, thermal dimensional stability, and laser peelability has not been satisfactory. satisfy. The object of the present invention is to provide a polyimide resin which has good mechanical properties, heat resistance and transparency, and is excellent in dimensional stability against heat and laser peelability. [Means to solve the problem]

The present inventors found that a polyimide resin containing a combination of specific structural units can solve the above-mentioned problems, and completed the present invention.

That is, the present invention relates to the following [1] to [7]. [1] A polyimide resin comprising a constituent unit A derived from a tetracarboxylic dianhydride and a constituent unit B derived from a diamine; the constituent unit A comprises a constituent unit derived from a compound represented by the following formula (a-1) ( A-1) and a constituent unit (A-2) derived from a compound represented by the following formula (a-2); the constituent unit B comprises a constituent unit (B-1) derived from a compound represented by the following formula (b-1) and A structural unit (B-2) derived from a compound represented by the following formula (b-2).

【Chemical 1】

In formula (a-2), L is a single bond or a divalent linking group; In formula (b-2), R is each independently a hydrogen atom, a fluorine atom, or a methyl group.

[2] The polyimide resin according to [1], wherein the ratio of the constituent unit (A-1) in the constituent unit A is 50 to 95 mol%, and the constituent unit (A-1) in the constituent unit A is 2) The ratio is 5~50 mole%. [3] The polyimide resin according to [1] or [2], wherein the structural unit (A-2) is selected from structural units derived from compounds represented by the following formula (a-2-1) ( A-2-1), the structural unit (A-2-2) derived from the compound represented by the following formula (a-2-2) and the structural unit (A-2-2) derived from the compound represented by the following formula (a-2-3) 2-3) At least one of the groups formed.

【Chemical 2】

[4] The polyimide resin according to any one of [1] to [3], wherein the ratio of the structural unit (B-1) in the structural unit B is 20 to 90 mol%, and the structural unit The ratio of the constituent unit (B-2) in B is 10-80 mol%. [5] The polyimide resin according to any one of [1] to [4], wherein R represents a hydrogen atom. [6] A polyimide varnish obtained by dissolving the polyimide resin according to any one of [1] to [5] in an organic solvent. [7] A polyimide film containing the polyimide resin according to any one of [1] to [5]. [Effect of Invention]

The polyimide resin of the present invention has good mechanical properties, heat resistance and transparency, and is excellent in dimensional stability against heat and laser peelability.

[Polyimide resin] The polyimide resin of the present invention comprises structural unit A derived from tetracarboxylic dianhydride and structural unit B derived from diamine; The constituent unit A comprises a constituent unit (A-1) derived from a compound represented by the following formula (a-1) and a constituent unit (A-2) derived from a compound represented by the following formula (a-2); the constituent unit B comprises A structural unit (B-1) derived from a compound represented by the following formula (b-1) and a structural unit (B-2) derived from a compound represented by the following formula (b-2).

【Chemical 3】

In formula (a-2), L is a single bond or a divalent linking group; In formula (b-2), R is each independently a hydrogen atom, a fluorine atom, or a methyl group.

＜Constituent Unit A＞ Structural unit A is a structural unit derived from tetracarboxylic dianhydride, including structural unit (A-1) derived from a compound represented by formula (a-1) and a structural unit (A-1) derived from a compound represented by formula (a-2). 2). By the structural unit (A-1), heat resistance, transparency, and dimensional stability are improved, and by the structural unit (A-2), dimensional stability and laser peelability are improved.

The compound represented by formula (a-1) is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetra Carboxylic dianhydride. In formula (a-2), L is a single bond or a divalent linking group. The above-mentioned divalent linking group is preferably a substituted or unsubstituted alkylene group, more preferably -CR ₁ R ₂ - (here, R ₁ and R ₂ are each independently a hydrogen atom, or a substituted or unsubstituted An alkyl group, or R ₁ and R ₂ are bonded to each other to form a ring.). L is preferably selected from the group consisting of a single bond, a group represented by the following formula (L-1), and a group represented by the following formula (L-2).

【Chemical 4】

The constituent unit (A-2) is preferably a constituent unit (A-2-1) derived from a compound represented by the following formula (a-2-1), a compound derived from a compound represented by the following formula (a-2-2) At least one of the structural unit (A-2-2) of and the structural unit (A-2-3) from the compound represented by the following formula (a-2-3) constitutes at least one of the group, more preferably selected from the group consisting of At least one of the group consisting of the structural unit (A-2-1) and the structural unit (A-2-2).

【Chemical 5】

The compound represented by the formula (a-2-1) is biphenyltetracarboxylic dianhydride (BPDA). Specific examples thereof include 3,3',4, 4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) represented by the following formula (a-2-1a), 2,2',3,3'-biphenyltetracarboxylic dianhydride (i-BPDA) represented by the following formula (a-2-1i).

【Chemical 6】

The compound represented by the formula (a-2-2) is 9,9'-bis(3,4-dicarboxyphenyl) fluorine dianhydride. The compound represented by the formula (a-2-3) is 4,4'-(hexafluoroisopropylidene)diphthalic anhydride.

The ratio of the constituent unit (A-1) in the constituent unit A is preferably 50-95 mole %, more preferably 55-95 mole %, further preferably 60-95 mole %, especially preferably 75-95 mole % Ear%. The ratio of the constituent unit (A-2) in the constituent unit A is preferably 5-50 mole %, more preferably 5-45 mole %, further preferably 5-40 mole %, especially preferably 5-25 mole % Ear%. The total content ratio of the constituent unit (A-1) and the constituent unit (A-2) in the constituent unit A is preferably 55 mol% or more, more preferably 60 mol% or more, further preferably 65 mol% or more , especially preferably more than 80 mole%. The upper limit of the total content ratio of the structural unit (A-1) and the structural unit (A-2) is not particularly limited, that is, 100 mol%. The structural unit A may consist only of a structural unit (A-1) and a structural unit (A-2).

Structural unit A may contain structural units other than structural units (A-1) and (A-2). Tetracarboxylic dianhydrides forming such structural units are not particularly limited, and examples thereof include aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride (except for compounds represented by formula (a-2). ); 1,2,3,4-cyclobutane tetracarboxylic dianhydride and 1,2,4,5-cyclohexane tetracarboxylic dianhydride and other alicyclic tetracarboxylic dianhydrides (except for formula (a-1) compounds); and aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butane tetracarboxylic dianhydride. In addition, in this specification, an aromatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride containing one or more aromatic rings, and an alicyclic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride containing one or more alicyclic rings and does not contain an aromatic ring. Cyclic tetracarboxylic dianhydrides and aliphatic tetracarboxylic dianhydrides refer to tetracarboxylic dianhydrides that do not contain an aromatic ring and do not contain an alicyclic ring. The structural units arbitrarily contained in the structural unit A (that is, structural units other than the structural units (A-1) and (A-2)) may be one type or two or more types.

<Constituent unit B> The structural unit B is a structural unit derived from a diamine, and includes a structural unit (B-1) derived from a compound represented by formula (b-1) and a structural unit (B-2) derived from a compound represented by formula (b-2). The mechanical properties and dimensional stability are improved by the constituent unit (B-1), and the heat resistance is improved by the constituent unit (B-2).

The compound represented by formula (b-1) is 2,2'-bis(trifluoromethyl)benzidine. In formula (b-2), R is each independently selected from the group consisting of hydrogen atom, fluorine atom, and methyl group, and is preferably a hydrogen atom. For the compound represented by formula (b-2), 9,9-bis(4-aminophenyl) fluorine, 9,9-bis(3-fluoro-4-aminophenyl) fluorine, and 9,9-bis(3-methyl-4-aminophenyl) fluorene, etc., preferably 9,9-bis(4-aminophenyl) fluorine.

The ratio of the constituent unit (B-1) in the constituent unit B is preferably 20 to 90 mol%, more preferably 45 to 85 mol%, and still more preferably 50 to 80 mol%. The ratio of the constituent unit (B-2) in the constituent unit B is preferably 10 to 80 mol%, more preferably 15 to 55 mol%, and still more preferably 20 to 50 mol%. The total content ratio of the constituent unit (B-1) and the constituent unit (B-2) in the constituent unit B is preferably 30 mol% or more, more preferably 60 mol% or more, further preferably 70 mol% or more . The upper limit of the total content ratio of the structural unit (B-1) and the structural unit (B-2) is not particularly limited, that is, 100 mol%. The structural unit B may consist only of a structural unit (B-1) and a structural unit (B-2).

Structural unit B may contain structural units other than structural units (B-1) and (B-2). There are no particular limitations on the diamine that forms such a structural unit, and examples include 1,4-phenylenediamine, p-xylylenediamine, 3,5-diaminobenzoic acid, 2,2'- Dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2-bis(4-amino Phenyl)hexafluoropropane, bis(4-aminophenyl)pyridine, 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, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl ]propane, and aromatic diamines such as 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (except compounds represented by formula (b-1) and compounds represented by formula (b-1) Compounds represented by -2); alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and ethylenediamine and hexa Aliphatic diamines such as methylenediamine. In addition, in this specification, an aromatic diamine refers to a diamine containing one or more aromatic rings, an alicyclic diamine refers to a diamine containing one or more alicyclic rings and does not contain an aromatic ring, and an aliphatic diamine Refers to diamines that do not contain aromatic rings and do not contain alicyclic rings. The structural units arbitrarily contained in the structural unit B (that is, structural units other than the structural units (B-1) and (B-2)) may be one type or two or more types.

The number average molecular weight of the polyimide resin of the present invention is preferably 5,000 to 100,000 in consideration of the mechanical strength of the obtained polyimide film. In addition, the number average molecular weight of a polyimide resin can be calculated|required from the standard polymethylmethacrylate (PMMA) conversion value measured by gel filtration chromatography, for example.

The polyimide resin of the present invention has good mechanical properties, heat resistance and transparency, and has excellent dimensional stability against heat and laser peeling property, so it can have the following physical properties. The tensile strength of the polyimide resin of the present invention is preferably 70 MPa or more, more preferably 85 MPa or more, further preferably 90 MPa or more, especially preferably 105 MPa or more. The tensile elastic modulus of the polyimide resin of the present invention is preferably above 2.2 GPa, more preferably above 2.4 GPa, further preferably above 2.8 GPa, especially preferably above 3.0 GPa.

The glass transition temperature (Tg) of the polyimide resin of the present invention is preferably above 350°C, more preferably above 380°C, further preferably above 400°C, especially above 430°C.

When the polyimide resin of the present invention is made into a polyimide film with a thickness of 10 μm, the total light transmittance should be above 85%, more preferably above 88%, further preferably above 90%, especially above 91%. .

The linear thermal expansion coefficient (CTE) of the polyimide resin of the present invention is preferably below 30ppm/°C, more preferably below 20ppm/°C, further preferably below 15ppm/°C, especially It should be below 10ppm/°C; as far as the CTE of 100~350°C is concerned, it should be below 35ppm/°C, more preferably below 30ppm/°C, further preferably below 25ppm/°C, especially below 20ppm/°C, most preferably It is preferably below 15ppm/°C.

When the polyimide resin of the present invention is made into a polyimide film with a thickness of 10 μm, the light transmittance at a wavelength of 308 nm should be below 2.5%, more preferably below 1.5%, further preferably below 1.0%, especially preferably below 0.5% %the following. The smaller the transmittance of light with a wavelength of 308nm, the better the laser stripping performance of the XeCl excimer laser with a wavelength of 308nm. In addition, the tensile elastic modulus, tensile strength, glass transition temperature (Tg), total light transmittance, linear thermal expansion coefficient (CTE), and light transmittance at a wavelength of 308nm of the present invention can be specifically determined by the examples Measured according to the method described.

Moreover, the polyimide resin-type yellow index (YI) of one aspect of this invention is small, that is, it is excellent in colorless transparency. Therefore, the yellowness index (YI) of a polyimide film having a thickness of 10 μm is preferably not more than 3.5, more preferably not more than 2.5, further preferably not more than 2.0, and especially preferably not more than 1.5. In addition, the yellowness index (YI) in this invention is specifically measured by the method described in an Example.

[Manufacturing method of polyimide resin] The polyimide resin of the present invention can be obtained by making a tetracarboxylic acid component containing a compound providing the above-mentioned structural unit (A-1) and a compound providing the above-mentioned structural unit (A-2) and a compound containing the above-mentioned structural unit (B) The compound of -1) is produced by reacting the diamine component of the compound providing the above-mentioned structural unit (B-2).

Compounds that provide the structural unit (A-1) include compounds represented by formula (a-1), but are not limited thereto, and may be represented by formula (a-1) as long as the same structural unit can be formed. derivatives of the compound. As such derivatives, tetracarboxylic acids corresponding to tetracarboxylic dianhydrides represented by the formula (a-1) (that is, norbornane-2-spiro-α-cyclopentanone-α'-spiro -2''-norbornane-5,5'',6,6''-tetracarboxylic acid), and alkyl esters of the tetracarboxylic acid. As the compound providing the constituent unit (A-1), a compound represented by formula (a-1) (that is, a dianhydride) is preferable. Compounds that provide the structural unit (A-2) include compounds represented by formula (a-2), but are not limited thereto, and may be represented by formula (a-2) as long as the same structural unit can be formed. derivatives of the compound. As this derivative, the tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by formula (a-2), and the alkyl ester of this tetracarboxylic acid are mentioned. As the compound providing the structural unit (A-2), it is preferably a compound represented by formula (a-2) (that is, a dianhydride).

Compounds that provide the structural unit (B-1) include compounds represented by formula (b-1), but are not limited thereto, and may be represented by formula (b-1) as long as the same structural unit can be formed. derivatives of the compound. Examples of such derivatives include diisocyanates corresponding to diamine represented by formula (b-1). As the compound providing the constituent unit (B-1), it is preferably a compound represented by formula (b-1) (that is, a diamine). Compounds that provide the structural unit (B-2) include compounds represented by formula (b-2), but are not limited thereto, and may be represented by formula (b-2) as long as the same structural unit can be formed. derivatives of the compound. Examples of such derivatives include diisocyanates corresponding to diamine represented by formula (b-2). As the compound providing the structural unit (B-2), it is preferably a compound represented by formula (b-2) (ie, diamine).

The tetracarboxylic acid component preferably contains 50-95 mole % of the compound providing the constituent unit (A-1), more preferably 55-95 mole %, further preferably 60-95 mole %, especially preferably 75-95 mole % Ear%. In addition, the tetracarboxylic acid component preferably contains 5-50 mole % of the compound providing the constituent unit (A-2), more preferably 5-45 mole %, further preferably 5-40 mole %, especially 5-50 mole % 25 mole%. In the tetracarboxylic acid component, the total of the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2) is preferably 55 mol% or more, more preferably 60 mol% or more, and still more preferably More than 65 mol%, especially preferably more than 80 mol%. The upper limit of the total content ratio of the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2) is not particularly limited, and may be 100 mol%. The tetracarboxylic acid component may consist only of the compound to which the structural unit (A-1) was given, and the compound to which the structural unit (A-2) was given.

The tetracarboxylic acid component may contain compounds other than the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2). For this compound, the above-mentioned aromatic tetracarboxylic dianhydrides, esters, etc. Cyclic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, and derivatives thereof (tetracarboxylic acid, alkyl ester of tetracarboxylic acid, etc.). The compounds optionally contained in the tetracarboxylic acid component (that is, compounds other than the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2)) may be one type or two or more types.

The diamine component preferably contains 20-90 mol % of the compound providing the constituent unit (B-1), more preferably 45-85 mol %, further preferably 50-80 mol %. In addition, the diamine component preferably contains 10-80 mole % of the compound providing the constituent unit (B-2), more preferably 15-55 mole %, and further preferably contains 20-50 mole %. The diamine component preferably contains 30 mol% or more of the total of the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2), more preferably 60 mol% or more, further preferably 70 mol% %above. The upper limit of the total content ratio of the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2) is not particularly limited, that is, it is 100 mol%. The diamine component may consist only of the compound which provides a structural unit (B-1) and the compound which provides a structural unit (B-2).

The diamine component may also contain compounds other than the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2). As for the compound, the above-mentioned aromatic diamine, alicyclic diamine, etc. Amines, aliphatic diamines, and their derivatives (diisocyanates, etc.). The compound arbitrarily contained in the diamine component (that is, compounds other than the compound providing the structural unit (B-1) and the compound providing the structural unit (B-2)) may be one type or two or more types.

In the present invention, the ratio of the added amount of the tetracarboxylic acid component used in the manufacture of the polyimide resin to the diamine component is relative to 1 mole of the tetracarboxylic acid component, and the diamine component is 0.9 to 1.1 moles. Ear.

Moreover, in this invention, in manufacture of a polyimide resin, you may use a terminal blocking agent other than the said tetracarboxylic-acid component and diamine component. The blocking agent is preferably a monoamine or a dicarboxylic acid. In terms of the amount of the end-capping agent to be introduced, it is preferably 0.0001-0.1 mole, especially 0.001-0.06 mole, relative to 1 mole of the tetracarboxylic acid component. As far as the monoamine blocking agent is concerned, it is recommended to be, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, etc. Among these, benzylamine and aniline are suitably used. The dicarboxylic acid-type end-capping agent is preferably a dicarboxylic acid, and a part thereof may be ring-closed. Suggestions are e.g. phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid Carboxylic acid, cyclohexane-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. Among these, phthalic acid and phthalic anhydride are suitably used.

The method of making the said tetracarboxylic-acid component and diamine component react is not specifically limited, A well-known method can be used. As far as the specific reaction method is concerned, it can be listed as follows: (1) Add the tetracarboxylic acid component, the diamine component, and the reaction solvent into the reactor, stir at room temperature ~ 80 ° C for 0.5 ~ 30 hours, and then raise the temperature to carry out the reaction process. The method of amination reaction, (2) After adding the diamine component and the reaction solvent into the reactor to dissolve it, add the tetracarboxylic acid component, and stir at room temperature ~ 80 ° C for 0.5 ~ 30 hours according to the demand, and then raise the temperature to carry out the amination reaction. The method of the amination reaction, (3) the method of adding the tetracarboxylic acid component, the diamine component, and the reaction solvent into the reactor, and raising the temperature immediately to carry out the imidization reaction, etc.

The reaction solvent used in the production of the polyimide resin may be any one that does not interfere with the imidization reaction and can dissolve the produced polyimide. Examples thereof include aprotic solvents, phenol-based solvents, ether-based solvents, carbonate-based solvents, and the like.

Specific examples of aprotic solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methyl Amide-based solvents such as caprolactam, 1,3-dimethylimidazolidinone, and tetramethylurea, lactone-based solvents such as γ-butyrolactone and γ-valerolactone, hexamethylphosphamide, Phosphorus-containing amide-based solvents such as hexamethylphosphine triamide; sulfur-containing solvents such as dimethylsulfoxide, dimethylsulfoxide, and cyclobutane (sulfolane); acetone, cyclohexanone, and methylcyclohexanone Ketone-based solvents such as picoline and pyridine; amine-based solvents such as picoline and pyridine; ester-based solvents such as acetic acid-2-methoxy-1-methylethyl ester, etc.

Specific examples of phenolic solvents 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, etc. Specific examples of ether solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy) Ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, 1,4-dioxane (1,4-dioxane), etc. Moreover, specific examples of carbonate-based solvents include diethyl carbonate, methylethyl carbonate, ethylene carbonate, propylene carbonate, and the like. Among the above-mentioned reaction solvents, amide-based solvents or lactone-based solvents are preferred. In addition, the said reaction solvent can be used individually or in mixture of 2 or more types.

For the imidization reaction, a Dean-Stark apparatus or the like is used, and it is preferable to carry out the reaction while removing water generated during production. By performing such an operation, the degree of polymerization and the imidization rate can be increased.

In the above-mentioned imidization reaction, a known imidization catalyst can be used. As an imidization catalyst, an alkali catalyst or an acid catalyst is mentioned. Examples of alkali catalysts include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine , tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, N,N-diethylaniline and other organic base catalysts; potassium hydroxide, sodium hydroxide, potassium carbonate , sodium carbonate, potassium bicarbonate, sodium bicarbonate and other inorganic alkali catalysts. In addition, examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, p- Toluenesulfonic acid, naphthalenesulfonic acid, etc. These imidization catalysts can be used individually or in combination of 2 or more types. Among the above, in view of operability, it is preferable to use an alkali catalyst, more preferably an organic alkali catalyst, and further preferably to use triethylamine, especially a combination of triethylamine and triethylenediamine.

The temperature of the imidization reaction is preferably 120 to 250°C, more preferably 160 to 200°C, in consideration of the reaction rate and gelation suppression. In addition, the reaction time is preferably 0.5 to 10 hours after the start of distillation of the produced water.

[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 is not particularly limited as long as it dissolves the polyimide resin, but it is preferable to use the above-mentioned compounds used as reaction solvents in the production of polyimide resin alone or in combination of two or more as the organic solvent. Because the polyimide resin of the present invention has solvent solubility, it can be made into a stable high-concentration varnish at room temperature. The content of the polyimide resin of the present invention in the polyimide varnish of the present invention is preferably 5 to 40% by mass, more preferably 10 to 30% by mass. The viscosity of polyimide varnish should be 1~200Pa･s, more preferably 5~150Pa･s. In addition, the polyimide varnish of the present invention may contain inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, and surfactants within the range that does not impair the properties required for polyimide films. , Spreading agent, defoaming agent, fluorescent whitening agent, crosslinking agent, polymerization initiator, photosensitive agent and other additives. The method for producing the polyimide varnish of the present invention is not particularly limited, and known methods can be applied.

[Polyimide film] The polyimide film of the present invention contains the polyimide resin of the present invention. Therefore, the polyimide film of the present invention has good mechanical properties, heat resistance and transparency, and is excellent in dimensional stability against heat and laser peelability. The method for producing the polyimide film of the present invention is not particularly limited, and known methods can be used. For example, a method of removing the organic solvent after coating or forming the polyimide varnish of the present invention into a film form, etc. may be mentioned.

The polyimide film of the present invention has good mechanical properties, heat resistance and transparency, and has excellent thermal dimensional stability and laser peelability, so it is suitable for use as color filters, flexible displays, semiconductor parts, Films for various components such as optical components. The polyimide film of the present invention is particularly suitable as a substrate for image display devices such as liquid crystal displays or OLED displays. [Example]

The following examples illustrate the present invention in detail, however, the present invention is not limited by these examples. The solid content concentration of the varnishes obtained in Examples and Comparative Examples and various physical properties of the polyimide film were measured by the methods shown below.

(1) Solid content concentration The solid content concentration of the varnish was measured by heating the sample at 320°C for 120 minutes with a small electric furnace "MMF-1" manufactured by AS ONE Corporation. The solid content concentration was calculated from the mass difference of the sample before and after heating. (2) Film thickness The film thickness was measured using a micrometer manufactured by Mitutoyo Corporation. (3) Tensile strength, tensile modulus of elasticity The measurement was performed using a tensile testing machine "STROGRAPH VG-1E" manufactured by Toyo Seiki Co., Ltd. in accordance with JIS K7127. (4) Glass transition temperature (Tg) Use the thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi High-Tech Science Corporation. In the tensile mode, the sample size is 2mm×20mm, the load is 0.1N, and the heating rate is 10℃/min. The temperature is raised to above Tg to remove the residual stress , and then perform TMA measurement under the same conditions from 50°C to 500°C to obtain Tg. (5) Total light transmittance, yellow index (YI) In accordance with JIS K7361-1, the measurement was performed using a simultaneous colorimeter and turbidity measuring instrument "COH400" manufactured by Nippon Denshoku Kogyo Co., Ltd. (6) Coefficient of thermal expansion (CTE) Using the thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi High-Tech Science Corporation., TMA was measured in tensile mode with a sample size of 2mm x 20mm, a load of 0.1N, and a heating rate of 10°C/min to obtain 100 CTE at ~200℃ and CTE at 100~350℃. (7) Light transmittance at a wavelength of 308nm Measurement was performed using an ultraviolet-visible-near-infrared spectrophotometer "UV-3100PC" manufactured by Shimadzu Corporation.

<Example 1> Add 2,2'-bis (Trifluoromethyl) benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd.) 16.012 g (0.050 mol), 9,9-bis(4-aminophenyl) fennel (manufactured by Tagoka Chemical Industry Co., Ltd. ) 17.423 g (0.050 mol), γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) 87.573 g, and stirred at a system internal temperature of 70° C. under a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution. Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) Co., Ltd.) 34.594 g (0.090 mol), 9,9'-bis(3,4-dicarboxyphenyl) stilbenic dianhydride (JFE Chemical Co., Ltd.) 4.584 g (0.010 mol), and γ - After adding 21.893 g of butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) to the solution together, 0.506 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) and triethylene glycol were added as imidization catalysts. 0.056 g of diamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was heated with a mantle heater, and the temperature in the reaction system was raised to 190° C. over about 20 minutes. The distilled components were collected and the rotation speed was adjusted according to the increase in viscosity, while the temperature in the reaction system was kept at 190° C. and reflux was performed for 5 hours. After that, 193.524 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and after cooling the temperature in the reaction system to 120° C., it was stirred for about 3 hours to make it uniform, and a polymer with a solid content concentration of 20% by mass was obtained. imide varnish. Then apply the obtained polyimide varnish to a glass plate, keep it on a heating plate at 80°C for 20 minutes, and then heat it in a hot air dryer at 400°C for 30 minutes under a nitrogen atmosphere to evaporate the solvent to obtain a 10 μm thick film. film. The results are shown in Table 1-1.

<Example 2> Change 9,9'-bis(3,4-dicarboxyphenyl) terpene dianhydride (manufactured by JFE Chemical Co., Ltd.) to the same molar amount of 3,3',4,4'-biphenyltetracarboxylic Acid dianhydride (s-BPDA) (manufactured by Mitsubishi Chemical Co., Ltd.), except that, a polyimide varnish was prepared in the same manner as in Example 1, and a polyimide varnish with a solid content concentration of 20% by mass was obtained. varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 11 μm was obtained. The results are shown in Table 1-1.

<Example 3> The amount of 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd.) was changed from 16.012g (0.050 mole) to 25.619g (0.080 mole), and 9,9 -The amount of bis(4-aminophenyl) terpene (manufactured by Tianoka Chemical Industry Co., Ltd.) was changed from 17.423g (0.050 mol) to 6.969g (0.020 mol), and in addition, it was the same as in Example 1 A polyimide varnish was prepared in the same manner to obtain a polyimide varnish with a solid content concentration of 20% by mass. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-1.

<Example 4> Change 9,9'-bis(3,4-dicarboxyphenyl) terpene dianhydride (manufactured by JFE Chemical Co., Ltd.) to the same molar amount of 3,3',4,4'-biphenyltetracarboxylic Acid dianhydride (s-BPDA) (manufactured by Mitsubishi Chemical Co., Ltd.), except that, a polyimide varnish was prepared in the same manner as in Example 3, and a polyimide varnish with a solid content concentration of 20% by mass was obtained. . Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-1.

<Example 5> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) Co., Ltd.) was changed from 34.594g (0.090 moles) to 30.750g (0.080 moles), and 9,9'-bis(3,4-dicarboxyphenyl) terpinedianhydride (JFE Chemical Co., Ltd. Except for changing the amount of 4.584 g (0.010 mol) to 9.169 g (0.020 mol), a polyimide varnish was prepared in the same manner as in Example 3 to obtain a solid content concentration of 20% by mass. polyimide varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-1.

<Example 6> Change 9,9'-bis(3,4-dicarboxyphenyl) fluorine dianhydride (manufactured by JFE Chemical Co., Ltd.) to the same molar amount of 4,4'-(hexafluoroisopropylidene) di Except for phthalic anhydride, a polyimide varnish was produced by the same method as in Example 5, and a polyimide varnish with a solid content concentration of 20% by mass was obtained. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 11 μm was obtained. The results are shown in Table 1-1.

<Example 7> Change 9,9'-bis(3,4-dicarboxyphenyl) terpene dianhydride (manufactured by JFE Chemical Co., Ltd.) to the same molar amount of 3,3',4,4'-biphenyltetracarboxylic Acid dianhydride (s-BPDA) (manufactured by Mitsubishi Chemical Co., Ltd.), except that, a polyimide varnish was prepared in the same manner as in Example 5, and a polyimide varnish with a solid content concentration of 20% by mass was obtained. . Using the obtained polyimide varnish, a film with a thickness of 11 μm was obtained by the same method as in Example 1. The results are shown in Table 1-1.

<Example 8> The amount of 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd.) was changed from 25.619g (0.080 mol) to 19.214g (0.060 mol), and 9,9 - The amount of bis(4-aminophenyl) terpene (manufactured by Tianoka Chemical Industry Co., Ltd.) was changed from 6.969 g (0.020 mole) to 13.938 g (0.040 mole). 4 A polyimide varnish was prepared in the same manner to obtain a polyimide varnish with a solid content concentration of 20% by mass. Using the obtained polyimide varnish, a film was produced in the same manner as in Example 1 to obtain a film with a thickness of 14 μm. The results are shown in Table 1-1.

<Example 9> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) company) was changed from 34.594g (0.090 mol) to 30.750g (0.080 mol), and 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (Mitsubishi Chemical (stock) Co., Ltd.) is changed from 2.942g (0.010 mol) to 5.884g (0.020 mol), except that, polyimide varnish is produced in the same way as in Example 8, and a solid content concentration of 20 is obtained. mass % polyimide varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-2.

<Example 10> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) company) was changed from 30.750g (0.080 mol) to 23.063g (0.060 mol), and 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (Mitsubishi Chemical (manufactured by Co., Ltd.) was changed from 5.884g (0.020 mol) to 11.768g (0.040 mol), except that, the polyimide varnish was produced by the same method as in Example 9, and the solid content concentration was obtained 20% by mass of polyimide varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 11 μm was obtained. The results are shown in Table 1-2.

<Example 11> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) company) was changed from 34.594g (0.090 mol) to 19.219g (0.050 mol), and 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (Mitsubishi Chemical (Co., Ltd.) was changed from 2.942g (0.010 mol) to 14.711g (0.050 mol), and 2,2'-bis(trifluoromethyl)benzidine (Wakayama Seika Kogyo Co., Ltd. manufactured) from 16.012g (0.050 mol) to 6.405g (0.020 mol), and the amount of 9,9-bis(4-aminophenyl) fennel (manufactured by Tianoka Chemical Industry Co., Ltd.) was changed from 17.423g (0.050 mol) was changed to 27.876g (0.080 mol), except that, the polyimide varnish was produced by the same method as in Example 2, and a polyimide varnish with a solid content concentration of 20% by mass was obtained . Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-2.

<Example 12> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) company) was changed from 34.594g (0.090 mol) to 26.906g (0.070 mol), and 9,9'-bis(3,4-dicarboxyphenyl) tertiary dianhydride (JFE Chemical Co., Ltd. Except for changing the amount of 4.584 g (0.010 mol) to 13.753 g (0.030 mol), a polyimide varnish was produced in the same manner as in Example 1 to obtain a solid content concentration of 20% by mass polyimide varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-2.

<Example 13> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) Co., Ltd.) was changed from 34.594g (0.090 moles) to 19.219g (0.050 moles), and 9,9'-bis(3,4-dicarboxyphenyl) terpinedianhydride (JFE Chemical Co., Ltd. Except for changing the amount of 4.584 g (0.010 mol) to 22.922 g (0.050 mol), a polyimide varnish was produced in the same manner as in Example 1 to obtain a solid content concentration of 20% by mass polyimide varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-2.

<Example 14> Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy (stock ) company) was changed from 34.594g (0.090 mol) to 19.219g (0.050 mol), and 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (Mitsubishi Chemical (made by Co., Ltd.) was changed from 2.942g (0.010 mol) to 14.711g (0.050 mol), except that, the polyimide varnish was produced by the same method as in Example 4, and the solid content concentration was obtained 20% by mass of polyimide varnish. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-2.

<Example 15> The amount of 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd.) was changed from 25.619g (0.080 mole) to 17.613g (0.055 mole), and 9,9 - The amount of bis(4-aminophenyl) terpene (manufactured by Tianoka Chemical Industry Co., Ltd.) was changed from 6.969 g (0.020 mole) to 15.680 g (0.045 mole). 3 A polyimide varnish was prepared in the same manner to obtain a polyimide varnish with a solid content concentration of 20% by mass. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 1-2.

＜Comparative example 1＞ Add 9,9-bis( 34.845 g (0.100 moles) of 4-aminophenyl) fennel (manufactured by Tianoka Chemical Industry Co., Ltd.), 88.395 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.), at a system internal temperature of 70° C. Under a nitrogen atmosphere, the solution was obtained by stirring at a rotation speed of 200 rpm. In this solution, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (manufactured by JX Energy Co., Ltd.) 38.438g (0.100 mol) and gamma-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) 22.099g are added together, and triethylamine ( Kanto Chemical Co., Ltd.) 0.506 g and triethylenediamine (Tokyo Chemical Industry Co., Ltd.) 0.056 g were heated with a heating pack, and the temperature in the reaction system was raised to 190° C. in about 20 minutes. The distilled components were collected and the rotational speed was adjusted according to the increase in viscosity, while the temperature in the reaction system was kept at 190° C. for 5 hours of reflux. After that, 191.840 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and after cooling the temperature in the reaction system to 120° C., it was stirred for about 3 hours to make it uniform, and a polyamide with a solid content concentration of 20% by mass was obtained. Imine varnish. Then, the obtained polyimide varnish was coated on a glass plate, kept at 80° C. for 20 minutes by a heating plate, and then, under a nitrogen atmosphere, the solvent was deactivated by heating at 400° C. for 30 minutes in a hot air drier. Evaporated to obtain a film with a thickness of 10 μm. The results are shown in Table 2.

＜Comparative example 2＞ The amount of 9,9-bis(4-aminophenyl) fennel (manufactured by Tianoka Chemical Industry Co., Ltd.) was changed from 34.845 g (0.100 mol) to 6.969 g (0.020 mol), and 2,2 '-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd.) 25.619g (0.080 mole), except that, with the same method as Comparative Example 1, a polyimide varnish was prepared, A polyimide varnish having a solid content concentration of 20% by mass was obtained. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 2.

＜Comparative example 3＞ The amount of 2,2'-bis(trifluoromethyl)benzidine (manufactured by Wakayama Seika Kogyo Co., Ltd.) was changed from 25.619g (0.080 mole) to 16.012g (0.050 mole), and 9,9 - The amount of bis(4-aminophenyl) terpene (manufactured by Tianoka Chemical Industry Co., Ltd.) was changed from 6.969 g (0.020 mole) to 17.423 g (0.050 mole). A polyimide varnish was prepared in the same manner to obtain a polyimide varnish with a solid content concentration of 20% by mass. Using the obtained polyimide varnish, a film was produced by the same method as in Example 1, and a film with a thickness of 10 μm was obtained. The results are shown in Table 2.

＜Comparative example 4＞ Add 9,9-bis( 34.845 g (0.100 moles) of 4-aminophenyl) fen (manufactured by Tianoka Chemical Industry Co., Ltd.), 77.404 g of N,N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) The temperature in the system was 50° C., and the solution was obtained by stirring at a rotation speed of 200 rpm under a nitrogen atmosphere. In this solution, 29.420 g (0.100 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) (manufactured by Mitsubishi Chemical Co., Ltd.) and N,N-diphenyl After 19.351 g of methylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added together, it took about 20 minutes to dissolve, and it was stirred at room temperature for 5 hours while adjusting the rotation speed according to the increase in viscosity. Thereafter, 166.194 g of N,N-dimethylformamide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added, stirred for about 1 hour to make it uniform, and a polyamic acid varnish with a solid content concentration of 20% by mass was obtained. Then apply the obtained polyamic acid varnish to a glass plate, keep it on a heating plate at 80°C for 20 minutes, and then heat it in a hot air dryer at 400°C for 30 minutes under a nitrogen atmosphere to make the polyamide The acid was imidized while evaporating the solvent in the varnish to obtain a film with a thickness of 8 μm. The results are shown in Table 2.

＜Comparative example 5＞ Change 9,9-bis(4-aminophenyl) fennel (manufactured by Tianoka Chemical Industry Co., Ltd.) to the same molar amount of 2,2'-bis(trifluoromethyl)benzidine (Wakayama Seika Industrial Co., Ltd.), except that, a polyamic acid varnish was produced by the method similar to Comparative Example 4, and a polyamic acid varnish with a solid content concentration of 20% by mass was obtained. Using the obtained polyamic acid varnish, a film was produced by the same method as in Comparative Example 4, and a film with a thickness of 22 μm was obtained. The results are shown in Table 2.

【Table 1-1】

【Table 1-2】

【Table 2】

The abbreviations in Table 1-1, Table 1-2 and Table 2 are as follows. CpODA: norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (formula (a -1) the compound indicated) BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (compound represented by formula (a-2)) BPAF: 9,9'-bis(3,4-dicarboxyphenyl) stilbenic dianhydride (compound represented by formula (a-2)) 6FDA: 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (compound represented by formula (a-2)) TFMB: 2,2'-bis(trifluoromethyl)benzidine (compound represented by formula (b-1)) BAFL: 9,9-bis(4-aminophenyl) fluorine (compound represented by formula (b-2))

As shown in Table 1-1 and Table 1-2, the polyimide films of Examples 1 to 15 have good mechanical properties, heat resistance and transparency, and are excellent in dimensional stability against heat and laser peelability. In addition, the polyimide films of Examples 1 to 10, 12, 13, and 15 have a small YI, that is, excellent colorless transparency. On the other hand, as shown in Table 2, the polyimide film of Comparative Example 1 has very poor dimensional stability to heat, and the polyimide film of Comparative Example 2 and 3 has very poor laser peelability. The polyimide film of 4 is not only very poor in thermal dimensional stability, but also poor in mechanical properties, and the polyimide film of Comparative Example 5 is not only very poor in thermal dimensional stability, but also poor in heat resistance.

Claims (7)

A kind of polyimide resin, comprises the constituent unit A from tetracarboxylic dianhydride and the constituent unit B from diamine; This constituent unit A comprises the constituent unit (A-1) from the compound represented by following formula (a-1) ) and a structural unit (A-2) derived from a compound represented by the following formula (a-2); the structural unit B comprises a structural unit (B-1) derived from a compound represented by the following formula (b-1) and derived from a compound represented by the following formula The constituent unit (B-2) of the compound represented by (b-2);

In formula (a-2), L is a single bond or a divalent linking group; in formula (b-2), R is each independently a hydrogen atom, a fluorine atom or a methyl group. Such as the polyimide resin of item 1 of the scope of the patent application, wherein, the ratio of the constituent unit (A-1) in the constituent unit A is 50~95 mole%, and the constituent unit (A-1) in the constituent unit A is 2) The ratio is 5~50 mole%. Such as the polyimide resin of claim 1 or 2 of the patent scope, wherein, the structural unit (A-2) is selected from the structural unit (A-2) of a compound represented by the following formula (a-2-1) 2-1), a structural unit (A-2-2) derived from a compound represented by the following formula (a-2-2) and a structural unit (A-2-2) derived from a compound represented by the following formula (a-2-3) 3) At least one of the groups formed;

Such as the polyimide resin of claim 1 or 2 of the patent scope, wherein, the ratio of the constituent unit (B-1) in the constituent unit B is 20-90 mole%, and the constituent unit (B-1) in the constituent unit B ( The ratio of B-2) is 10 to 80 mol%. Such as the polyimide resin of item 1 or 2 of the scope of application, wherein R represents a hydrogen atom. A polyimide varnish is formed by dissolving the polyimide resin in any one of items 1 to 5 of the patent application in an organic solvent. A polyimide film, containing the polyimide resin according to any one of items 1 to 5 in the scope of the patent application.