Polyimide resin composition, polyimide varnish, and polyimide film

Abstract

A polyimide resin composition comprising a polyimide resin and a crosslinking agent having at least two oxazolyl groups, wherein the polyimide resin is a polyimide resin having a constituent unit A derived from tetracarboxylic acid dianhydride and a constituent unit B derived from a diamine, and wherein constituent unit B comprises a constituent unit (B-1) derived from a diamine having a sulfonyl group in its structure and a constituent unit (B-2) derived from a specific compound represented by 3,5-DABA.

Description

Technology Field

[0001] The present invention relates to a polyimide resin composition, a polyimide varnish, and a polyimide film. Background Technology

[0002] Polyimide resins are being considered for various applications in fields such as electrical and electronic components. For example, there is a desire to replace glass substrates used in image display devices, such as liquid crystal displays or OLED displays, with plastic substrates for the purpose of making the device lighter or more flexible, and research is being conducted on polyimide films suitable as such plastic substrates.

[0003] In an image display device, when light emitted from a display element passes through a plastic substrate and is emitted, the plastic substrate is required to be colorless and transparent. Furthermore, when light passes through a phase difference film or a polarizer (e.g., liquid crystal display, touch panel, etc.), in addition to being colorless and transparent, high optical isotropy (i.e., low Rth) is also required.

[0004] In addition, when a polyimide film is used as a substrate, a target electronic circuit is formed on the polyimide film through various processes, such as sputtering or etching processes, to form oxide semiconductor films, such as indium tin oxide (ITO) films, depending on the application. When forming a target electronic circuit on a polyimide film, it is necessary to ensure the flatness of the polyimide film. Therefore, the polyimide film is adhered to a rigid support such as a glass plate, and then peeled off from the support after cooling.

[0005] As a method for adhering a polyimide film to a support, in addition to the method of adding an adhesive to the polyimide itself, a method is known in which a layer called a so-called release layer is interposed between the polyimide film and the support to ensure adhesion during the process.

[0006] In addition, the following method is known as a method for peeling a polyimide film from a support.

[0007] (1) A method for peeling off polyimide resin by obtaining a structure including a polyimide resin / support and then irradiating a laser from the support side to ablate the polyimide resin interface (see, for example, Patent Document 1). The types of lasers include solid-state (YAG) lasers and gas (UV excimer) lasers, and a spectrum such as 308 nm is used.

[0008] (2) A method of forming a release layer on a support before coating a resin composition on the support, and then obtaining a composition comprising a polyimide resin film / release layer / support and mechanically peeling off the polyimide resin film (see, for example, Patent Document 2). As for the release layer, there are methods using perylene (registered trademark, manufactured by Japan Perylene Co., Ltd.) or tungsten oxide, or methods using vegetable oil-based, silicone-based, fluorine-based, or alkyd-based release agents. In addition, laser irradiation as described in (1) above may be used in combination.

[0009] In addition, Patent Document 3 discloses a method of fixing a resin substrate to a support substrate by interposing an adhesive layer, forming an electronic element on the resin substrate, and peeling off an electronic device including the electronic element and the resin substrate from the support substrate, wherein the adhesive layer is composed mainly of a material that reduces adhesion to the support substrate upon contact with moisture. Prior art literature

[0010] Japanese Patent Publication No. 2007-512568, Japanese Patent Publication No. 2010-067957, Japanese Patent Publication No. 2016-021384 The problem to be solved

[0011] In the method according to (1) above, an expensive laser irradiation device is required, and there were cases where the resin substrate formed on the gas phase was damaged during laser irradiation. In the method according to (2) above, the combination of the types of the peeling layer and polyimide was limited in order to achieve performance.

[0012] In the method of Patent Document 3, when forming an electronic device, it was necessary to form a sealing layer that encapsulates the exposed areas of the adhesive layer to prevent the adhesive layer from coming into contact with moisture so as not to reduce the adhesive strength. On the other hand, when peeling off the electronic device after forming the electronic device, it was necessary to remove the sealing layer before peeling to allow the adhesive layer to come into contact with moisture. Therefore, the method of Patent Document 3 was a cumbersome process overall. Furthermore, there was a problem in that it was necessary to install the device in a high-humidity environment of 90% or more to allow contact with moisture, making it difficult to control the moisture content and difficult to secure stable peelability. Moreover, the polyimide used in Patent Document 3 utilized phenylenediamine, which has strong intramolecular charge transfer interactions, and thus was prone to discoloration, resulting in low transparency; additionally, due to its structure in which polymer molecules are easily arranged, it had low optical isotropy.

[0013] As such, according to the above method, optical properties such as colorless transparency and optical isotropy of the film were degraded due to damage, the addition of a peeling layer, or the characteristics of the polymer, and the yield also tended to deteriorate.

[0014] As such, there was a demand for a polyimide resin that could easily and stably peel off a polyimide film from a glass substrate or a silicon substrate while maintaining optical properties such as high colorless transparency and optical isotropy of the obtained polyimide film.

[0015] Accordingly, the present invention aims to provide a polyimide resin composition capable of forming a film having excellent colorless transparency and optical isotropy, and further having excellent peelability from a substrate, and a polyimide varnish and a polyimide film comprising the polyimide resin composition. means of solving the problem

[0016] The inventors have discovered that a polyimide resin composition comprising a specific combination of constituent units and a specific crosslinking agent can solve the above problem, and have thus completed the invention.

[0017] That is, the present invention is, the following <1> ~ <11> It is about.

[0018] <1> A polyimide resin composition comprising a polyimide resin and a crosslinking agent having at least two oxazolyl groups, wherein the polyimide resin is a polyimide resin having a constituent unit A derived from a tetracarboxylic acid dianhydride and a constituent unit B derived from a diamine, and wherein constituent unit B comprises a constituent unit (B-1) derived from a diamine having a sulfonyl group in its structure and a constituent unit (B-2) derived from a compound represented by the following formula (b-2).

[0019] [Chemical Formula 1]

[0020]

[0021] (In formula (b-2), X is a single bond, a substituted or unsubstituted alkylene group, a carbonyl group, an ether group, a group represented by the following formula (b-2-i), or a group represented by the following formula (b-2-ii); p is an integer from 0 to 2; m1 is an integer from 0 to 4; and m2 is an integer from 0 to 4. However, if p is 0, m1 is an integer from 1 to 4.)

[0022] [Chemical Formula 2]

[0023]

[0024] (In Equation (b-2-i), m3 is an integer from 0 to 5; in Equation (b-2-ii), m4 is an integer from 0 to 5. Meanwhile, m1+m2+m3+m4 is greater than or equal to 1, and when p is 2, each of the two Xs and the two m2~m4s are selected independently.)

[0025] <2> The constituent unit (B-2) is a constituent unit (B-21) derived from a compound represented by the following formula (b-21), the above <1> Polyimide resin composition described in

[0026] [Chemical Formula 3]

[0027]

[0028] <3> The constituent unit (B-1) is at least one selected from the group consisting of a constituent unit (B-11) derived from a compound represented by the following formula (b-11), a constituent unit (B-12) derived from a compound represented by the following formula (b-12), and a constituent unit (B-13) derived from a compound represented by the following formula (b-13). <1> or <2> Polyimide resin composition described in

[0029] [Chemical Formula 4]

[0030]

[0031] <4> The constituent unit A comprises at least one selected from the group consisting of 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). <1> ~ <3> Polyimide resin composition described in any one of the following.

[0032] [Chemical Formula 5]

[0033]

[0034] <5> The constituent unit B further comprises a constituent unit (B-3) derived from a compound represented by the following formula (b-3), the above <1> ~ <4> Polyimide resin composition described in any one of the following.

[0035] [Chemical Formula 6]

[0036]

[0037] (In Equation (b-3), Z 1 and Z 2 Each independently represents a divalent aliphatic group that may contain an oxygen atom, or a divalent aromatic group, and R 1 and R 2 Each independently represents a monovalent aromatic group or a monovalent aliphatic group, and R 3 and R 4 Each independently represents a monovalent aliphatic group, and R 5 and R 6 Each represents independently a monovalent aliphatic group or a monovalent aromatic group, m and n each represent independently an integer greater than or equal to 1, and the sum of m and n represents an integer between 2 and 1000. However, R 1 and R 2 At least one of the groups represents a monovalent aromatic group.)

[0038] <6> The constituent unit B further comprises a constituent unit (B-4) derived from a compound represented by the following formula (b-4), wherein the above <1> ~ <5> Polyimide resin composition described in any one of the following.

[0039] [Chemical Formula 7]

[0040]

[0041] <7> The above crosslinking agent is a compound comprising an aromatic ring or an aromatic heterocyclic ring to which at least two oxazolyl groups are bonded, the <1> ~ <6> Polyimide resin composition described in any one of the following.

[0042] <8> The above crosslinking agent is a compound comprising a benzene ring to which at least two oxazolyl groups are bonded, the <1> ~ <7> Polyimide resin composition described in any one of the following.

[0043] <9> The above crosslinking agent is 1,3-bis(4,5-dihydro-2-oxazolyl)benzene, the above <1> ~ <8> Polyimide resin composition described in any one of the following.

[0044] <10> The above <1> ~ <9> A polyimide varnish formed by dissolving a polyimide resin composition described in any one of the above into an organic solvent.

[0045] <11> The above <1> ~ <9> A polyimide film formed by crosslinking the polyimide resin in the polyimide resin composition described in any one of the above by the crosslinking agent. Effects of the invention

[0046] According to the present invention, a film having excellent colorless transparency and optical isotropy, and furthermore excellent peelability from a substrate can be formed. Specific details for implementing the invention

[0047] [Polyimide Resin Composition]

[0048] The polyimide resin composition of the present invention comprises a polyimide resin and a crosslinking agent. Hereinafter, the polyimide resin and the crosslinking agent in the present invention will be described.

[0049] Meanwhile, although the exact reason why the polyimide resin composition of the present invention maintains optical properties such as colorless transparency and optical isotropy while exhibiting excellent peelability is unclear, it is believed that stacking between imides is inhibited by the curved polymer molecular structure derived from a diamine monomer having sulfonyl groups in the main chain, resulting in excellent optical properties such as optical isotropy and the ability to reduce residual stress in the resulting polyimide film, thus providing excellent peelability.

[0050] Polyimide Resin

[0051] The polyimide resin included in the polyimide resin composition of the present invention has a constituent unit A derived from tetracarboxylic acid dianhydride and a constituent unit B derived from a diamine, wherein constituent unit B comprises a constituent unit (B-1) derived from a diamine having a sulfonyl group in its structure and a constituent unit (B-2) derived from a compound represented by the following formula (b-2).

[0052] [Chemical Formula 8]

[0053]

[0054] (In formula (b-2), X is a single bond, a substituted or unsubstituted alkylene group, a carbonyl group, an ether group, a group represented by the following formula (b-2-i), or a group represented by the following formula (b-2-ii); p is an integer from 0 to 2; m1 is an integer from 0 to 4; and m2 is an integer from 0 to 4. However, if p is 0, m1 is an integer from 1 to 4.)

[0055] [Chemical Formula 9]

[0056]

[0057] (In Equation (b-2-i), m3 is an integer from 0 to 5; in Equation (b-2-ii), m4 is an integer from 0 to 5. Meanwhile, m1+m2+m3+m4 is greater than or equal to 1, and when p is 2, each of the two Xs and the two m2~m4s are selected independently.)

[0058] (Constituent Unit A)

[0059] Constituent unit A is a constituent unit derived from tetracarboxylic acid dianhydride that occupies the polyimide resin.

[0060] It is preferable that the constituent unit A includes at least one selected from the group consisting of 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), and it is more preferable to include the constituent unit (A-2). By including the constituent unit (A-2), colorless transparency and optical isotropy can be improved, and residual stress can also be reduced.

[0061] Meanwhile, it is more desirable to include the constituent unit (A-1), particularly in terms of colorless transparency and heat resistance.

[0062] [Chemical Formula 10]

[0063]

[0064] The compound represented by formula (a-1) is norbonan-2-spiro-α-cyclopentanone-α'-spiro-2”-norbonan-5,5”,6,6”-tetracarboxylic acid dianhydride. By including constituent unit A as constituent unit (A-1), the colorless transparency and heat resistance of the film can be improved.

[0065] The proportion of constituent unit (A-1) in constituent unit A is preferably 40 mol% or more, more preferably 50 mol% or more, and even more preferably 60 mol% or more. The upper limit of the proportion of constituent unit (A-1) is not specifically limited, i.e., 100 mol%. Constituent unit A may consist only of constituent unit (A-1).

[0066] The compound represented by formula (a-2) is 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride. By including constituent unit A in constituent unit (A-2), the colorless transparency and optical isotropy of the film can be improved, and furthermore, residual stress can be reduced.

[0067] The proportion of constituent unit (A-2) in constituent unit A is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more. The upper limit of the proportion of constituent unit (A-2) is not specifically limited, i.e., 100 mol%. Constituent unit A may consist only of constituent unit (A-2).

[0068] When constituent unit A includes constituent unit (A-1) and constituent unit (A-2), the ratio of the total of constituent units (A-1) and (A-2) in constituent unit A is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio of the total of constituent units (A-1) and (A-2) is not specifically limited, i.e., 100 mol%. Constituent unit A may consist only of constituent unit (A-1) and constituent unit (A-2).

[0069] Constituent unit A may include constituent units other than constituent units (A-1) and (A-2).

[0070] Constituent unit A may include, in addition to constituent units (A-1) and (A-2), a constituent unit (A-3) derived from an acid anhydride modified silicon at both ends.

[0071] As the above-mentioned acid anhydride modified silicone, a compound represented by the following formula (a-3) is preferred.

[0072] [Chemical Formula 11]

[0073]

[0074] (among Equation (a-3),

[0075] R 31 ~R 36 Each is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and

[0076] L 31 and L 32Each is independently a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms, and

[0077] Z 31 and Z 32 Each is independently a trivalent hydrocarbon group having 1 to 20 carbon atoms, and

[0078] n3 is 1 to 200.

[0079] R in Equation (a-3) 31 ~R 36 Each is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0080] Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 3 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, aryl groups having 7 to 20 carbon atoms, and alkenyl groups having 2 to 20 carbon atoms.

[0081] As for the alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 10 carbon atoms is preferred, and examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, and a hexyl group. As for the cycloalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms is preferred, and examples include a cyclopentyl group and a cyclohexyl group. As for the aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms is preferred, and examples include a phenyl group and a naphthyl group. As for the aralkyl group having 7 to 20 carbon atoms, an aralkyl group having 7 to 10 carbon atoms is preferred, and examples include a benzyl group and a phenethyl group. As for the alkenyl group having 2 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms is preferred, and examples include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, and a butenyl group.

[0082] R in Equation (a-3) 31 ~R 36Each is independently selected, preferably, from the group consisting of an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an alkenyl group having 2 to 20 carbon atoms; more preferably, selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and an alkenyl group having 2 to 10 carbon atoms; and even more preferably, selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an alkenyl group having 2 to 10 carbon atoms; Particularly preferably selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, phenyl, naphthyl, vinyl, allyl, propenyl, isopropenyl, and butenyl groups; most preferably selected from the group consisting of methyl, ethyl, phenyl, and vinyl groups.

[0083] L in equation (a-3) 31 and L 32 Each is independently a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms.

[0084] Examples of divalent hydrocarbon groups having 1 to 20 carbon atoms include alkylene groups having 1 to 20 carbon atoms, cycloalkylene groups having 3 to 20 carbon atoms, and arylene groups having 6 to 20 carbon atoms.

[0085] As for the alkylene group having 1 to 20 carbon atoms, an alkylene group having 1 to 10 carbon atoms is preferred, and examples include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group.

[0086] As for the cycloalkylene group having 3 to 20 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms is preferred, and examples include a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, and a cycloheptylene group.

[0087] As for the arylene group having 6 to 20 carbon atoms, the arylene group having 6 to 10 carbon atoms is preferred, and examples include the phenylene group and the naphthylene group.

[0088] L 31 and L 32 Each is independently selected, preferably, from the group consisting of a single bond, an alkylene group having 1 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, and an arylene group having 6 to 20 carbon atoms; more preferably, selected from the group consisting of a single bond, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, and an arylene group having 6 to 10 carbon atoms; even more preferably, selected from the group consisting of a single bond, an alkylene group having 1 to 10 carbon atoms, and an arylene group having 6 to 10 carbon atoms; particularly preferably, selected from the group consisting of a single bond, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a phenylene group, and a naphthylene group; most preferably, selected from the group consisting of a single bond, a methylene group, an ethylene group, a propylene group, and a phenylene group.

[0089] Z in Equation (a-3) 31 and Z 32 Each is independently a trivalent hydrocarbon group having 1 to 20 carbon atoms.

[0090] Z in Equation (a-3) 31 and Z 32 Each is selected independently, preferably, from the group consisting of the group represented by the following formula (a-3-i), the group represented by the following formula (a-3-ii), the group represented by the following formula (a-3-iii), and the group represented by the following formula (a-3-iv).

[0091] [Chemical Formula 12]

[0092]

[0093] The group represented by formula (a-3-i) is a succinic acid residue, the group represented by formula (a-3-ii) is a phthalic acid residue, the group represented by formula (a-3-iii) is a 2,3-norvonandicarboxylic acid residue, and the group represented by (a-3-iv) is a 5-norbornene-2,3-dicarboxylic acid residue. Meanwhile, among formulas (a-3-i) to (a-3-iv), "*" indicates the bonding position.

[0094] n3 in formula (a-3) is 1 to 200. n3 is preferably 3 to 150, and more preferably 5 to 120.

[0095] Examples of commercially available acid anhydride-modified silicones include "X22-168AS," "X22-168A," "X22-168B," and "X22-168-P5-8" manufactured by Shin-Etsu Chemical Co., Ltd., and "DMS-Z21" manufactured by Gerest.

[0096] When constituent unit A includes constituent unit (A-3), the proportion of constituent unit (A-3) in constituent unit A is preferably 1 to 50 mol%, more preferably 2 to 40 mol%, and even more preferably 3 to 30 mol%.

[0097] By additionally including constituent unit A (A-3), the colorless transparency can be improved while maintaining low residual stress of the film.

[0098] Constituent units other than constituent units (A-1) and (A-2) optionally included in constituent unit A are not limited to constituent unit (A-3). Tetracarboxylic acid dianhydrides that impart such optional constituent units are not particularly limited, but may include aromatic tetracarboxylic acid dianhydrides such as pyromellitic acid dianhydride, 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, and 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride; alicyclic tetracarboxylic acid dianhydrides such as 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride (excluding compounds represented by formula (a-1) or (a-2); and aliphatic tetracarboxylic acid dianhydrides such as 1,2,3,4-butanetetracarboxylic acid dianhydride.

[0099] Meanwhile, in the present specification, an aromatic tetracarboxylic acid dianhydride means a tetracarboxylic acid dianhydride containing one or more aromatic rings, an alicyclic tetracarboxylic acid dianhydride means a tetracarboxylic acid dianhydride containing one or more alicyclic rings and not an aromatic ring, and an aliphatic tetracarboxylic acid dianhydride means a tetracarboxylic acid dianhydride containing neither aromatic rings nor alicyclic rings.

[0100] Constituent units other than constituent units (A-1) and (A-2) optionally included in constituent unit A may be of one type or two or more types.

[0101] (Constituent Unit B)

[0102] Constituent unit B is a constituent unit derived from a diamine that occupies the polyimide resin, and includes a constituent unit (B-1) derived from a diamine having a sulfonyl group in its structure and a constituent unit (B-2) derived from a compound represented by the following formula (b-2).

[0103] [Chemical Formula 13]

[0104]

[0105] (In formula (b-2), X is a single bond, a substituted or unsubstituted alkylene group, a carbonyl group, an ether group, a group represented by the following formula (b-2-i), or a group represented by the following formula (b-2-ii); p is an integer from 0 to 2; m1 is an integer from 0 to 4; and m2 is an integer from 0 to 4. However, if p is 0, m1 is an integer from 1 to 4.)

[0106] [Chemical Formula 14]

[0107]

[0108] (In Equation (b-2-i), m3 is an integer from 0 to 5; in Equation (b-2-ii), m4 is an integer from 0 to 5. Meanwhile, m1+m2+m3+m4 is greater than or equal to 1, and when p is 2, each of the two Xs and the two m2~m4s are selected independently.)

[0109] Meanwhile, in equations (b-2-i) and (b-2-ii), "*" indicates the joining position.

[0110] The constituent unit (B-1) derived from a diamine having a sulfonyl group in its structure is preferably at least one selected from the group consisting of a constituent unit (B-11) derived from a compound represented by the following formula (b-11), a constituent unit (B-12) derived from a compound represented by the following formula (b-12), and a constituent unit (B-13) derived from a compound represented by the following formula (b-13).

[0111] [Chemical Formula 15]

[0112]

[0113] The compound represented by formula (b-11) is bis(3-aminophenyl)sulfone (3,3'-DDS), the compound represented by formula (b-12) is bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS), and the compound represented by formula (b-13) is bis[4-(3-aminophenoxy)phenyl]sulfone (BAPS-M).

[0114] The polyimide resin used in the composition of the present invention comprises at least one diamine-derived constituent unit selected from the group consisting of compounds represented by formulas (b-11), (b-12), and (b-13), thereby improving the colorless transparency and optical isotropy of the polyimide film obtained.

[0115] When the constituent unit (B-1) includes the constituent unit (B-12), it is preferable to use it in combination with the constituent unit (B-13) from the perspective of optical isotropy. That is, from the perspective of optical isotropy, the constituent unit (B-1) preferably includes the constituent unit (B-12) and the constituent unit (B-13).

[0116] It is thought that using a diamine having a sulfonyl group affects the flexibility of the polymer molecular chain and affects the peelability of the polyimide film. Furthermore, it is thought that the sulfonyl group in the diamine inhibits intramolecular charge transfer and inhibits electron conjugation, thereby improving the colorless transparency and optical isotropy when made into a polyimide film.

[0117] Specific examples of compounds represented by formula (b-2) include compounds represented by any one of the following formulas (b-21) to (b-27).

[0118] [Chemical Formula 16]

[0119]

[0120] Specific examples of the compound represented by formula (b-21) include the compound represented by the following formula (b-211), namely 3,5-diaminobenzoic acid.

[0121] [Chemical Formula 17]

[0122]

[0123] The constituent unit (B-2) is preferably a constituent unit (B-21) derived from a compound represented by formula (b-21), and more preferably a constituent unit (B-211) derived from a compound represented by formula (b-211).

[0124] By including constituent unit B as constituent unit (B-2), the heat resistance and chemical resistance of the film are improved.

[0125] The proportion of the constituent unit (B-1) in the constituent unit B is preferably 15 to 95 mol%, more preferably 20 to 95 mol% in terms of heat resistance, even more preferably 50 to 90 mol%, and even more preferably 70 to 85 mol%.

[0126] The proportion of the constituent unit (B-2) in the constituent unit B is preferably 5 to 85 mol%, more preferably 5 to 80 mol%, even more preferably 10 to 50 mol%, and even more preferably 15 to 30 mol%.

[0127] The molar ratio [(B-1) / (B-2)] of the constituent unit (B-1) and the constituent unit (B-2) in constituent unit B is preferably 15 / 85 to 95 / 5, and from the perspective of reducing residual stress or improving elongation, it is more preferably 15 / 85 to 70 / 30, even more preferably 15 / 85 to 50 / 50, and even more preferably 15 / 85 to 40 / 60.

[0128] The ratio of the total of constituent units (B-1) and (B-2) in constituent unit B is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. The upper limit of the ratio of the total of constituent units (B-1) and (B-2) is not specifically limited, i.e., 100 mol%. Constituent unit B may consist only of constituent unit (B-1) and constituent unit (B-2).

[0129] It is preferable that constituent unit B includes a constituent unit (B-3) derived from a compound represented by the following formula (b-3). By including the constituent unit (B-3) in constituent unit B, the colorless transparency and optical isotropy of the film are improved, and residual stress is reduced.

[0130] [Chemical Formula 18]

[0131]

[0132] In Equation (b-3), Z 1 and Z 2 Each independently represents a divalent aliphatic group that may contain an oxygen atom, or a divalent aromatic group, and R 1 and R 2 Each independently represents a monovalent aromatic group or a monovalent aliphatic group, and R 3 and R 4 Each independently represents a monovalent aliphatic group, and R 5 and R 6 Each represents independently a monovalent aliphatic group or a monovalent aromatic group, m and n each represent independently an integer greater than or equal to 1, and the sum of m and n represents an integer between 2 and 1000. However, R 1 and R 2 At least one of them represents a monovalent aromatic group.

[0133] Meanwhile, in Equation (b-3), two or more different repeating units listed in parallel by [ ] may each be repeated in any form and order of random, alternating, or block.

[0134] In Equation (b-3), Z 1 and Z 2 The divalent aliphatic group or divalent aromatic group in the above may be substituted with a fluorine atom. Examples of divalent aliphatic groups include divalent saturated or unsaturated aliphatic groups having 1 to 20 carbon atoms, and aliphatic groups containing an oxygen atom. The number of carbon atoms of the divalent aliphatic group is preferably 3 to 20.

[0135] Examples of divalent saturated aliphatic groups include alkylene groups having 1 to 20 carbon atoms, such as methylene groups, ethylene groups, propylene groups, trimethylene groups, tetramethylene groups, hexamethylene groups, octamethylene groups, decamethylene groups, dodecamethylene groups, etc.

[0136] Examples of divalent unsaturated aliphatic groups include alkylene groups having 2 to 20 carbon atoms, such as vinylene groups, propenylene groups, and alkylene groups having an unsaturated double bond at the terminal end.

[0137] Aliphatic groups containing oxygen atoms include alkyleneoxy groups and aliphatic groups having ether bonds.

[0138] Examples of divalent aromatic groups include arylene groups with 6 to 20 carbon atoms and aralylene groups with 7 to 20 carbon atoms. Z 1 and Z 2 Specific examples of arylene groups having 6 to 20 carbon atoms include o-phenylene groups, m-phenylene groups, p-phenylene groups, 4,4'-biphenylylene groups, 2,6-naphthylene groups, etc.

[0139] Z in Equation (b-3) 1 and Z 2 In particular, trimethylene groups and p-phenylene groups are preferred, and trimethylene groups are more preferred.

[0140] In Equation (b-3), R 1 ~R 6 Examples of monovalent aliphatic groups include monovalent saturated or unsaturated aliphatic groups. Examples of monovalent saturated aliphatic groups include alkyl groups having 1 to 22 carbon atoms, such as methyl groups, ethyl groups, and propyl groups. Examples of monovalent unsaturated aliphatic groups include alkenyl groups having 2 to 22 carbon atoms, such as vinyl groups and propenyl groups. These groups may be substituted with fluorine atoms.

[0141] R of Equation (b-3) 1 , R 2 , R 5 and R6 Examples of monovalent aromatic groups include an aryl group having 6 to 20 carbon atoms, an aryl group having 7 to 30 carbon atoms substituted with an alkyl group, and an aralkyl group having 7 to 30 carbon atoms. Among the monovalent aromatic groups, an aryl group is preferred, and a phenyl group is more preferred.

[0142] R in Equation (b-3) 1 and R 2 At least one side of represents a monovalent aromatic group, R 1 and R 2 It is desirable that all are monovalent aromatic groups, and R 1 and R 2 It is more desirable that all of them are phenyl groups.

[0143] R in Equation (b-3) 3 and R 4 In the case of the group, an alkyl group having 1 to 6 carbon atoms is preferred, and a methyl group is more preferred.

[0144] R in Equation (b-3) 5 and R 6 As for the group, a monovalent aliphatic group is preferred, and a methyl group is more preferred.

[0145] As described above, among the compounds represented by formula (b-3), the compound represented by the following formula (b-31) is preferred.

[0146] [Chemical Formula 19]

[0147]

[0148] (In Equation (b-31), m and n are equivalent to m and n in Equation (b-3), respectively, and the preferred ranges are also the same.)

[0149] In formula (b-3), m represents the number of repetitions of a siloxane unit to which at least one aromatic group is attached, and in formula (b-3), n represents the number of repetitions of a siloxane unit to which one aliphatic group is attached.

[0150] In equation (b-3), m and n each independently represent an integer greater than or equal to 1, and the sum of m and n (m+n) represents an integer from 2 to 1000. The sum of m and n is preferably an integer from 3 to 500, more preferably from 3 to 100, and even more preferably from 3 to 50.

[0151] The ratio of m / n in formula (b-3) is preferably 5 / 95 to 50 / 50, more preferably 10 / 90 to 40 / 60, and even more preferably 20 / 80 to 30 / 70.

[0152] The functional group equivalent (amine equivalent) of the compound represented by formula (b-3) is preferably 150 to 5,000 g / mol, more preferably 400 to 4,000 g / mol, and even more preferably 500 to 3,000 g / mol.

[0153] Meanwhile, the functional group equivalent refers to the mass of the compound represented by formula (b-3) per mole of functional group (amino group).

[0154] Among the compounds represented by formula (b-3) that are available as commercial products, examples include “X-22-9409”, “X-22-1660B”, “X-22-161AS”, “X-22-161A”, and “X-22-161B” manufactured by Shin-Etsu Chemical Co., Ltd.

[0155] The proportion of the constituent unit (B-3) in the constituent unit B is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, even more preferably 3 to 15 mol%, even more preferably 5 to 15 mol%, and even more preferably 7 to 15 mol%.

[0156] It is preferable that constituent unit B includes a constituent unit (B-4) derived from a compound represented by the following formula (b-4). By including constituent unit B with constituent unit (B-4), the colorless transparency of the film is improved.

[0157] [Chemical Formula 20]

[0158]

[0159] The proportion of the constituent unit (B-4) in the constituent unit B is preferably 1 to 50 mol%, more preferably 5 to 45 mol%, even more preferably 5 to 40 mol%, even more preferably 10 to 40 mol%, and even more preferably 10 to 30 mol%.

[0160] Constituent unit B may include constituent units other than constituent units (B-1) to (B-4). Diamines providing such constituent units are not particularly limited, but include 1,4-phenylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminobenzanilide, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)terephthalamide, 4,4'-bis(4-aminophenoxy)biphenyl, Examples include aromatic diamines such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, and 9,9-bis(4-aminophenyl)fluorene (excluding compounds represented by any one of formulas (b-1) to (b-4); alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine (excluding compounds represented by formula (b-1) and compounds represented by formula (b-3)).

[0161] Meanwhile, in this specification, an aromatic diamine means a diamine containing one or more aromatic rings, a diamine alicyclic means a diamine containing one or more alicyclic rings and not an aromatic ring, and an aliphatic diamine means a diamine that does not contain either an aromatic ring or alicyclic rings.

[0162] Constituent units other than constituent units (B-1) to (B-4) optionally included in constituent unit B may be of one type or two or more types.

[0163] The number average molecular weight of the polyimide resin is preferably 5,000 to 100,000 in terms of the mechanical strength of the polyimide film obtained. Meanwhile, the number average molecular weight of the polyimide resin can be obtained, for example, from the standard polymethyl methacrylate (PMMA) equivalent value obtained by gel filtration chromatography measurement.

[0164] Polyimide resins may include structures other than polyimide chains (structures formed by imide bonding between constituent unit A and constituent unit B). Examples of structures other than polyimide chains that may be included in polyimide resins include structures containing amide bonds.

[0165] It is preferable that the polyimide resin contains polyimide chains (a structure formed by imide bonding between constituent unit A and constituent unit B) as the main structure. Accordingly, the proportion of polyimide chains in the polyimide resin is preferably 50 mass% or more, more preferably 70 mass% or more, even more preferably 90 mass% or more, and particularly preferably 99 mass% or more.

[0166] The polyimide resin composition of the present invention comprising the above-mentioned polyimide resin can form a film with excellent colorless transparency, optical isotropy, and peelability, and the suitable physical property values ​​of the film are as follows.

[0167] The total light transmittance is preferably 88% or more when the film is 10 μm thick, more preferably 89% or more, and even more preferably 90% or more.

[0168] The yellow index (YI) is preferably 5.0 or less when the film is 10 μm thick, more preferably 4.0 or less, and even more preferably 3.0 or less.

[0169] The residual stress is preferably 25.0 MPa or less, more preferably 24.0 MPa or less, and even more preferably 22.0 MPa or less.

[0170] The absolute value of the thickness phase difference (Rth) is preferably 100 nm or less, more preferably 60 nm or less, and even more preferably 35 nm or less when using a film with a thickness of 10 μm. In this range, optical isotropy is excellent.

[0171] In addition, the film that can be formed using the above-mentioned polyimide resin has good heat resistance and mechanical properties, and possesses the following favorable physical property values.

[0172] The glass transition temperature (Tg) is preferably 250°C or higher, more preferably 270°C or higher, and even more preferably 280°C or higher.

[0173] The tensile modulus is preferably 2.0 GPa or higher, more preferably 2.5 GPa or higher, and even more preferably 2.6 GPa or higher.

[0174] The tensile elongation is preferably 5%, more preferably 6% or more, even more preferably 7% or more, and even more preferably 10% or more.

[0175] If the tensile modulus and tensile elongation are within the above ranges, the peelability of the film from the substrate during processing becomes good.

[0176] Meanwhile, the physical property values ​​described above in the present invention can be specifically measured by the method described in the examples.

[0177] Method for manufacturing polyimide resin

[0178] In the present invention, the polyimide resin can be prepared by reacting a tetracarboxylic acid component containing a compound that provides the above-described constituent unit A with a diamine component containing a compound that provides the above-described constituent unit (B-1) and a compound that provides the above-described constituent unit (B-2).

[0179] Examples of compounds imparting constituent unit A include compounds represented by formula (a-1) and compounds represented by formula (a-2), but are not limited thereto and may also be derivatives thereof within the scope of imparting the same constituent unit. Examples of such derivatives include tetracarboxylic acids corresponding to tetracarboxylic acid dianhydrides represented by formulas (a-1) and (a-2) (i.e., norbonan-2-spiro-α-cyclopentanone-α'-spiro-2”-norbonan-5,5”,6,6”-tetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid), and alkyl esters of said tetracarboxylic acids. Among these, tetracarboxylic acid dianhydrides represented by formulas (a-1) and (a-2) are preferred.

[0180] The tetracarboxylic acid component preferably contains 40 mol% or more of a compound providing the constituent unit (A-1), more preferably 50 mol% or more, and even more preferably 60 mol% or more. The upper limit of the content of the compound providing the constituent unit (A-1) is not particularly limited, i.e., 100 mol%. The tetracarboxylic acid component may consist only of the compound providing the constituent unit (A-1).

[0181] The tetracarboxylic acid component preferably contains 50 mol% or more of a compound providing the constituent unit (A-2), more preferably 70 mol% or more, and even more preferably 85 mol% or more. The upper limit of the content of the compound providing the constituent unit (A-2) is not particularly limited, i.e., 100 mol%. The tetracarboxylic acid component may consist only of the compound providing the constituent unit (A-2).

[0182] When the tetracarboxylic acid component comprises a compound that provides a constituent unit (A-1) and a compound that provides a constituent unit (A-2), the tetracarboxylic acid component preferably comprises at least 50 mol% of the compound that provides the constituent unit (A-1) and the compound that provides the constituent unit (A-2), more preferably at least 70 mol%, even more preferably at least 90 mol%, and particularly preferably at least 99 mol%. The upper limit of the compound that provides the constituent unit (A-1) and the compound that provides the constituent unit (A-2) is not specifically limited, i.e., 100 mol%. The tetracarboxylic acid component may consist only of the compound that provides the constituent unit (A-1) and the compound that provides the constituent unit (A-2).

[0183] The tetracarboxylic acid component may include compounds other than the compound providing the constituent unit (A-1) and the compound providing the constituent unit (A-2).

[0184] The tetracarboxylic acid component may additionally include a compound that provides a constituent unit (A-3) in addition to the compound that provides a constituent unit (A-1) and the compound that provides a constituent unit (A-2).

[0185] Examples of compounds providing the constituent unit (A-3) include bilateral acid anhydride-modified silicon (e.g., a compound represented by formula (a-3)), but are not limited thereto and may also be derivatives thereof within the scope of providing the same constituent unit. Examples of such derivatives include tetracarboxylic acids corresponding to bilateral acid anhydride-modified silicon and alkyl esters of said tetracarboxylic acids. As for the compound providing the constituent unit (A-3), bilateral acid anhydride-modified silicon (i.e., a dihydride) is preferred.

[0186] When the tetracarboxylic acid component includes a compound that provides a constituent unit (A-3), the tetracarboxylic acid component preferably includes 1 to 50 mol% of the compound that provides the constituent unit (A-3), more preferably 2 to 40 mol%, and even more preferably 3 to 30 mol%.

[0187] Compounds other than the compound that provides the constituent unit (A-1) optionally included in the tetracarboxylic acid component and the compound that provides the constituent unit (A-2) are not limited to the compound that provides the constituent unit (A-3). Examples of such optional compounds include the aromatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, and aliphatic tetracarboxylic acid dianhydrides described above, and their derivatives (tetracarboxylic acid, alkyl esters of tetracarboxylic acid, etc.).

[0188] Compounds other than the compound that provides the constituent unit (A-1) optionally included in the tetracarboxylic acid component and the compound that provides the constituent unit (A-2) may be one type or two or more types.

[0189] Compounds that impart the constituent unit (B-1) include compounds represented by formula (b-11), compounds represented by formula (b-12), and compounds represented by formula (b-13), but are not limited thereto and may also be derivatives thereof within the scope of imparting the same constituent unit. Examples of such derivatives include diisocyanates corresponding to the diamine represented by formula (b-11), diisocyanates corresponding to the diamine represented by formula (b-12), and diisocyanates corresponding to the diamine represented by formula (b-13). Among these, diamines represented by formulas (b-11), (b-12), and (b-13) are preferred.

[0190] Likewise, the compound providing the constituent unit (B-2) may be a compound represented by formula (b-2), but is not limited thereto and may be a derivative thereof within the scope of providing the same constituent unit. The derivative may be a diisocyanate corresponding to the diamine represented by formula (b-2). The compound providing the constituent unit (B-2) is preferably a compound represented by formula (b-2) (i.e., a diamine).

[0191] The diamine component contains a compound that provides a constituent unit (B-1), preferably 15 to 95 mol%, more preferably 20 to 95 mol%, even more preferably 50 to 90 mol%, and even more preferably 70 to 85 mol%.

[0192] The diamine component contains a compound that provides a constituent unit (B-2), preferably 5 to 85 mol%, more preferably 5 to 80 mol%, even more preferably 10 to 50 mol%, and even more preferably 15 to 30 mol%.

[0193] The diamine component comprises, in total, a compound providing a constituent unit (B-1) and a compound providing a constituent unit (B-2), preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the total content of the compound providing a constituent unit (B-1) and the compound providing a constituent unit (B-2) is not specifically limited, i.e., 100 mol%. The diamine component may consist only of a compound providing a constituent unit (B-1) and a compound providing a constituent unit (B-2).

[0194] The diamine component may include compounds other than the compound providing the constituent unit (B-1) and the compound providing the constituent unit (B-2).

[0195] The diamine component may additionally include a compound that provides a constituent unit (B-3) in addition to the compound that provides a constituent unit (B-1) and the compound that provides a constituent unit (B-2).

[0196] Examples of compounds that provide the constituent unit (B-3) include compounds represented by formula (b-3), but are not limited thereto and may also be derivatives thereof within the scope of providing the same constituent unit. Examples of such derivatives include diisocyanates corresponding to the diamine represented by formula (b-3). As for the compound providing the constituent unit (B-3), the compound represented by formula (b-3) (i.e., diamine) is preferred.

[0197] The diamine component contains a compound that provides a constituent unit (B-3), preferably 1 to 25 mol%, more preferably 2 to 20 mol%, even more preferably 3 to 15 mol%, even more preferably 5 to 15 mol%, and even more preferably 7 to 15 mol%.

[0198] The diamine component may additionally include a compound that provides a constituent unit (B-4) in addition to the compound that provides a constituent unit (B-1) and the compound that provides a constituent unit (B-2).

[0199] Examples of compounds that provide the constituent unit (B-4) include compounds represented by formula (b-4), but are not limited thereto and may also be derivatives thereof within the scope of providing the same constituent unit. Examples of such derivatives include diisocyanates corresponding to the diamine represented by formula (b-4). As for the compound providing the constituent unit (B-4), the compound represented by formula (b-4) (i.e., diamine) is preferred.

[0200] The diamine component preferably contains 1 to 50 mol% of a compound providing a constituent unit (B-4), more preferably 5 to 45 mol%, even more preferably 5 to 40 mol%, even more preferably 10 to 40 mol%, and even more preferably 10 to 30 mol%. In addition, particularly from the perspective of reducing residual stress, it preferably contains 1 to 50 mol%, more preferably 10 to 50 mol%, and even more preferably 20 to 40 mol%.

[0201] Compounds other than the compound providing the constituent unit (B-1) and the compound providing the constituent unit (B-2) optionally included in the diamine component are not limited to the compound providing the constituent unit (B-3) and the compound providing the constituent unit (B-4). Examples of such optional compounds include the aromatic diamines, alicyclic diamines, and aliphatic diamines described above, and their derivatives (such as diisocyanates).

[0202] Compounds other than the compound that provides the constituent unit (B-1) optionally included in the diamine component and the compound that provides the constituent unit (B-2) may be one type or two or more types.

[0203] In the present invention, the ratio of the input amounts of the tetracarboxylic acid component and the diamine component used in the manufacture of the polyimide resin is preferably 0.9 to 1.1 moles of the diamine component per 1 mole of the tetracarboxylic acid component.

[0204] In addition, in the present invention, in addition to the aforementioned tetracarboxylic acid component and diamine component, a terminal encapsulant may be used for the manufacture of the polyimide resin. Monoamines or dicarboxylic acids are preferred as terminal encapsulants. The amount of terminal encapsulant introduced is preferably 0.0001 to 0.1 mole per 1 mole of tetracarboxylic acid component, and particularly preferably 0.001 to 0.06 mole. Examples of monoamine terminal encapsulants include 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 may be suitably used. As for dicarboxylic acid terminal encapsulators, dicarboxylic acids are preferred, and some of them may have closed rings. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. are suggested. Among these, phthalic acid and phthalic anhydride can be used appropriately.

[0205] There are no particular restrictions on the method of reacting the tetracarboxylic acid component and the diamine component of the invention, and known methods can be used.

[0206] Specific reaction methods include: (1) a method of introducing a tetracarboxylic acid component, a diamine component, and a reaction solvent into a reactor, stirring at room temperature to 80°C for 0.5 to 30 hours, and then raising the temperature to carry out an imidation reaction; (2) a method of introducing a diamine component and a reaction solvent into a reactor and dissolving them, then introducing a tetracarboxylic acid component, stirring at room temperature to 80°C for 0.5 to 30 hours as needed, and then raising the temperature to carry out an imidation reaction; and (3) a method of introducing a tetracarboxylic acid component, a diamine component, and a reaction solvent into a reactor and immediately raising the temperature to carry out an imidation reaction.

[0207] The reaction solvent used in the manufacture of polyimide resins only needs to be capable of dissolving the resulting polyimide without inhibiting the imidization reaction. Examples include aprotic solvents, phenolic solvents, etheric solvents, carbonate solvents, etc.

[0208] Specific examples of aprotic solvents include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, lactone solvents such as γ-butyrolactone (GBL), γ-valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoricamide, hexamethylphosphintriamide, sulfur-containing solvents such as dimethylsulfone, dimethyl sulfoxide, sulfolane, ketone solvents such as acetone, cyclohexanone, methylcyclohexanone, amine solvents such as picoline, pyridine, and ester solvents such as acetic acid (2-methoxy-1-methylethyl).

[0209] 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.

[0210] Specific examples of ether-based 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, etc.

[0211] In addition, specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, etc.

[0212] Among the above reaction solvents, amide-based solvents or lactone-based solvents are preferred. In addition, the above reaction solvents may be used alone or in a mixture of two or more types.

[0213] In the imidation reaction, it is preferable to carry out the reaction while removing water generated during manufacturing using a Dean Stark apparatus or the like. By performing such operations, the degree of polymerization and the imidation rate can be further increased.

[0214] In the above imidation reaction, a known imidation catalyst may be used. Examples of imidation catalysts include base catalysts or acid catalysts.

[0215] Examples of base catalysts include organic base catalysts such as pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-rutidine, 2,6-rutidine, trimethylamine, triethylamine (TEA), tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, N,N-diethylaniline, and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

[0216] In addition, examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexanoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxycyanoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, etc. The above imidization catalysts may be used alone or in combination of two or more types.

[0217] Among the above, from the perspective of handling ease, it is preferable to use a base catalyst, more preferable to use an organic base catalyst, even more preferable to use triethylamine, and particularly preferable to use a combination of triethylamine and triethylenediamine.

[0218] The temperature of the imidation reaction is preferably 120 to 250°C, more preferably 160 to 200°C, in terms of the reaction rate and inhibition of gelation. In addition, the reaction time is preferably 0.5 to 10 hours after the start of the discharge of the generated water.

[0219] <Cross-linking agent>

[0220] In the present invention, the crosslinking agent has at least two oxazolyl groups. That is, the crosslinking agent in the present invention is a polyfunctional oxazolin compound having two or more oxazolyl groups (oxazolin ring) in the molecule.

[0221] The oxazolyl group is reactive with the carboxyl group, and when the carboxyl group and the oxazolyl group react, an amide ester bond is formed as shown below. This reaction proceeds particularly easily when heated above 80°C.

[0222] [Chemical Formula 21]

[0223]

[0224] Since the polyimide resin included in the polyimide resin composition of the present invention has carboxyl groups, when the polyimide resin composition of the present invention is heated, the polyimide resins cross-link with each other through the interposition of a cross-linking agent, thereby forming a cross-linked polyimide resin. For this reason, the chemical resistance of the film is improved.

[0225] The crosslinking agent is not particularly limited as long as it is a polyfunctional oxazolin compound having two or more oxazolyl groups in the molecule, and specific examples thereof include 1,3-bis(4,5-dihydro-2-oxazolyl)benzene, 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, 2,2'-bis(2-oxazolin), Japan Catalytic Co., Ltd.'s "K-2010E", "K-2020E", "K-2030E", 2,6-bis(4-isopropyl-2-oxazolin-2-yl)pyridine, 2,6-bis(4-phenyl-2-oxazolin-2-yl)pyridine, 2,2'-isopropylidenebis(4-phenyl-2-oxazolin), 2,2'-isopropylidenebis(4-terthulbutyl-2-oxazolin), etc.

[0226] The crosslinking agent is preferably a compound comprising an aromatic ring or an aromatic heterocyclic ring to which at least two oxazolyl groups are attached, more preferably a compound comprising a benzene ring or a pyridine ring to which at least two oxazolyl groups are attached, even more preferably a compound comprising a benzene ring to which at least two oxazolyl groups are attached, and particularly preferably 1,3-bis(4,5-dihydro-2-oxazolyl)benzene.

[0227] Crosslinking agents may be used alone or in combination of two or more types.

[0228] The polyimide resin composition of the present invention preferably comprises a polyimide resin and a crosslinking agent in a ratio such that the molar ratio (oxazolyl group / carboxyl group) between the oxazolyl group in the crosslinking agent and the carboxyl group in the polyimide resin is in the range of 1 / 8 to 1 / 0.5. More preferably, the molar ratio is 1 / 6 to 1 / 1, and even more preferably 1 / 4 to 1 / 2.

[0229] Meanwhile, the above molar ratio refers to the molar ratio between the oxazolyl group included in the crosslinking agent and the carboxyl group included in the compound that provides the constituent unit (B-2) used in the manufacture of the polyimide resin, and is calculated based on the amount of crosslinking agent added and the amount of the compound that provides the constituent unit (B-2).

[0230] [Polyimide Varnish]

[0231] As a suitable embodiment of the polyimide resin composition of the present invention, a polyimide resin composition (hereinafter also referred to as “polyimide varnish”) can be provided, wherein, in addition to the polyimide resin and the crosslinking agent described above, an organic solvent is additionally included, and the polyimide resin is dissolved in the said organic solvent.

[0232] The organic solvent may be any solvent that dissolves the polyimide resin and is not particularly limited, but it is preferable to use the above-described compound as a reaction solvent used in the manufacture of the polyimide resin, either alone or in a mixture of two or more.

[0233] Polyimide varnish may be a solution in which a polyimide resin obtained by polymerization is dissolved in a reaction solvent, to which a crosslinking agent is added, or a solution in which a diluent solvent and a crosslinking agent are added.

[0234] The polyimide varnish preferably contains 5 to 40 mass% of polyimide resin, more preferably 7 to 30 mass%, and even more preferably 8 to 20 mass%. The viscosity of the polyimide varnish is preferably 50 to 5000 Pa·s, more preferably 100 to 4000 Pa·s, and even more preferably 300 to 3500 Pa·s. The viscosity of the polyimide varnish is a value measured at 25°C using an E-type viscometer.

[0235] In addition, the polyimide varnish of the present invention may include various additives such as inorganic fillers, adhesion promoters, release agents, flame retardants, UV stabilizers, surfactants, leveling agents, defoaming agents, fluorescent whitening agents, crosslinking agents, polymerization initiators, and photosensitive agents, to the extent that the required characteristics of the polyimide film are not impaired.

[0236] The method for manufacturing the polyimide varnish of the present invention is not particularly limited, and known methods may be applied.

[0237] [Polyimide Film]

[0238] The polyimide film of the present invention is formed by crosslinking the polyimide resin described above, which is included in the polyimide resin composition of the present invention, with the crosslinking agent described above. That is, the polyimide film of the present invention comprises a crosslinked polyimide resin, which is a crosslinked product of polyimide resins interposed with a crosslinking agent. Accordingly, the polyimide film of the present invention has excellent heat resistance, colorless transparency, and chemical resistance, and furthermore, has low residual stress. The suitable physical properties of the polyimide film of the present invention are as described above.

[0239] The method for manufacturing a polyimide film according to the present invention is not particularly limited as long as it includes a crosslinking process at a temperature (preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 150°C or higher) at which the crosslinking reaction between the polyimide resin and the crosslinking agent proceeds. For example, a method may be used in which the polyimide varnish described above is applied onto a smooth support such as a glass plate, a metal plate, or plastic, or formed into a film, and then heated. Through this heat treatment, the crosslinking reaction between the polyimide resin and the crosslinking agent in the polyimide varnish proceeds, while organic solvents such as reaction solvents or diluents contained in the polyimide varnish can be removed. If necessary, a release agent may be applied to the surface of the support in advance.

[0240] The following method is preferred for the heat treatment. Specifically, it is preferable to first evaporate the organic solvent at a temperature of 120°C or lower, and then dry it at a temperature above the boiling point of the organic solvent to produce a polyimide film. Additionally, it is preferable to dry under a nitrogen atmosphere. The pressure of the drying atmosphere may be reduced pressure, atmospheric pressure, or increased pressure. By drying at two different temperatures, a film with a smooth surface and no defects can be obtained. Furthermore, the drying temperature for the second stage is not particularly limited, but is preferably 200 to 450°C, more preferably 300 to 430°C, and particularly preferably 350 to 400°C. By drying within this temperature range, the transparency and yellowness of the film are improved, and furthermore, good solvent resistance is obtained.

[0241] In addition, the polyimide film of the present invention may also be manufactured using a polyamide acid varnish formed by dissolving a polyamide acid and a crosslinking agent in an organic solvent.

[0242] The polyamide acid included in the above polyamide acid varnish is a product of a heavy addition reaction between a tetracarboxylic acid component containing a compound that provides the aforementioned constituent unit A, a compound that provides the aforementioned constituent unit (B-1), and a diamine component containing a compound that provides the aforementioned constituent unit (B-2), as a precursor of the polyimide resin in the present invention. By imidizing (dehydrating and cloning) this polyamide acid, a polyimide resin is obtained.

[0243] As the organic solvent included in the above polyamide acid varnish, the organic solvent included in the polyimide varnish of the present invention may be used.

[0244] In the present invention, the polyamide acid varnish may be the polyamide acid solution itself obtained by adding a tetracarboxylic acid component containing a compound providing the above-described constituent unit A, a diamine component containing a compound providing the above-described constituent unit (B-1), and a compound providing the above-described constituent unit (B-2) in a reaction solvent, or it may be a polyamide acid solution to which a diluent solvent has been further added.

[0245] A method for manufacturing a polyimide film using a polyamide acid varnish includes a crosslinking process at a temperature (preferably 80°C or higher, more preferably 100°C or higher, even more preferably 150°C or higher) at which the crosslinking reaction between the polyimide resin and the crosslinking agent proceeds, and known methods may be used. For example, a polyamide acid varnish may be applied or formed into a film on a smooth support such as a glass plate, a metal plate, a silicon wafer, or a plastic, and an organic solvent such as a reaction solvent or a diluent contained in the varnish may be removed by heating to obtain a polyamide acid film, and the polyamide acid in the polyamide acid film may be imidized by heating, and further crosslinked by reacting the polyimide resin with the crosslinking agent.

[0246] The heating temperature for obtaining a polyamide film by drying the polyamide varnish is preferably 50 to 120°C. The heating temperature for imidizing the polyamide by heating is preferably 200 to 400°C.

[0247] Meanwhile, the imidation method is not limited to thermal imidation, and chemical imidation may also be applied.

[0248] The thickness of the polyimide film of the present invention can be appropriately selected according to the application, etc., preferably in the range of 1 to 250 μm, more preferably 5 to 100 μm, and even more preferably 10 to 80 μm. Since the thickness is 1 to 250 μm, practical use as a self-supporting film becomes possible.

[0249] The thickness of the polyimide film can be easily controlled by adjusting the solid content or viscosity of the polyimide varnish.

[0250] The polyimide film of the present invention is suitably used as a film for various components such as color filters, flexible displays, semiconductor components, and optical components. The polyimide film of the present invention is particularly suitably used as a substrate for image display devices such as liquid crystal displays or OLED displays.

[0251] Examples

[0252] The present invention will be specifically explained below by way of examples. However, the present invention is not limited in any way by these examples.

[0253] The solid content concentration of the varnish and each physical property of the film obtained in the examples and comparative examples were measured by the method shown below.

[0254] (1) Solid content concentration

[0255] The solid content of the varnish was measured by heating the sample at 320°C × 120 min in a small electric furnace “MMF-1” manufactured by As One Co., Ltd., and calculating it from the difference in mass of the sample before and after heating.

[0256] (2) Film thickness

[0257] The film thickness was measured using a micrometer manufactured by Mitutoyo Corporation.

[0258] (3) Total light transmittance, Yellow Index (YI)

[0259] Total light transmittance and YI were measured in accordance with JIS K7105:1997 using the color and turbidity simultaneous measuring instrument “COH7700” manufactured by Nippon Color Industry Co., Ltd.

[0260] (4) Hayes

[0261] Measurements were performed in accordance with JIS K7361-1 using the "COH400" color and turbidity simultaneous measuring instrument manufactured by Nippon Jeonsaekyo Co., Ltd.

[0262] (5)b *

[0263] b * The color and turbidity were measured in accordance with JIS Z8781:2013 using the color and turbidity simultaneous measuring instrument “COH7700” manufactured by Japan Color Industry Co., Ltd.

[0264] (6) In-plane retardation (Re)

[0265] In-plane retardation (Re) was measured using an ellipsometer “M-220” manufactured by Nippon Spectroscopic Corporation. The value of the in-plane phase difference was measured at a measurement wavelength of 590 nm.

[0266] (7) Thickness phase difference (Rth)

[0267] The thickness phase difference (Rth) was measured using an ellipsometer "M-220" manufactured by Nippon Spectroscopic Corporation. The value of the thickness phase difference was measured at a measurement wavelength of 590 nm. Meanwhile, Rth is expressed by the following formula, where the maximum refractive index within the plane of the polyimide film is nx, the minimum is ny, the refractive index in the thickness direction is nz, and the thickness of the film is d.

[0268] Rth=[{(nx+ny) / 2}-nz]×d

[0269] (8) Peeling power

[0270] The peel strength between the polyimide film and the glass interface was measured using the "Strograph EII-L05" tensile testing machine manufactured by Toyo Seiki Co., Ltd. The test specimen used was a polyimide film formed on a glass plate with dimensions of 10 mm × 100 mm. A test specimen with one end of the film peeled off was installed horizontally in the apparatus, the end of the film was fitted into the chuck, and the stress at which the peeled film and the glass were pulled at an angle of approximately 90° was defined as the peel strength. Meanwhile, the tensile test speed was set to 50 mm / min.

[0271] (9) Glass transition temperature (Tg)

[0272] Using the thermomechanical analyzer “TMA / SS6100” manufactured by Hitachi High-Tech Science Co., Ltd., the sample was heated to a temperature sufficient to remove residual stress under conditions of sample size 2 mm × 20 mm, load 0.1 N, and heating rate 10 ℃ / min in tensile mode, and then cooled to room temperature. After that, the elongation of the test specimen was measured under the same conditions as the treatment for removing residual stress, and the point where the inflection point of elongation was observed was determined as the glass transition temperature.

[0273] (10)1% weight loss temperature (Td 1%)

[0274] The 1% weight loss temperature was determined using a thermogravimetric analyzer ("TG / DTA6200" manufactured by Seiko Instruments Co., Ltd.) with a sample of approximately 10 mg.

[0275] It was determined by measuring the temperature at which the sample weight decreases by 1% by weight relative to 100% by weight of the sample weight at 100℃ when the temperature is raised from room temperature to 450℃ under the condition of a heating rate of 10℃ / min.

[0276] Meanwhile, under conditions of an air gas flow rate of 50 mL / min in an air atmosphere and a nitrogen gas flow rate of 100 mL / min in a nitrogen atmosphere, the temperature was raised, respectively.

[0277] (11) Residual stress

[0278] Polyimide varnish or polyamide varnish was applied using a spin coater onto a 4-inch silicon wafer with a thickness of 525 μm ± 25 μm, for which the "warping amount" had been measured in advance using the residual stress measuring device "FLX-2320" manufactured by KLA Tenkors, and pre-baked. Afterward, a heat curing treatment was performed using a hot air dryer at 350 to 400°C for 30 minutes under a nitrogen atmosphere, and a silicon wafer with a polyimide film attached having a film thickness of 8 to 15 μm after curing was produced. The warping amount of this wafer was measured using the aforementioned residual stress measuring device, and the residual stress generated between the silicon wafer and the polyimide film was evaluated.

[0279] (12) Chemical resistance 1 (PGMEA)

[0280] A solvent was applied dropwise at room temperature to a polyimide film formed on a glass plate, and it was checked whether there was any change on the film surface. Meanwhile, propylene glycol monomethyl ether acetate (PGMEA) was used as the solvent.

[0281] The evaluation criteria for content formulation were as follows.

[0282] ○: There was no change on the film surface.

[0283] △: A slight crack formed on the film surface.

[0284] ×: Cracks formed on the film surface, or the film surface dissolved.

[0285] (13) Chemical resistance 2 (acid resistance)

[0286] The polyimide film deposited on the glass plate was immersed in a mixed acid solution (a mixed solution of H3PO4 (70 mass%) + HNO3 (10 mass%) + CH3COOH (5 mass%) + H2O (15 mass%)) heated to 40°C for 4 minutes, and then washed with water. After washing, the moisture was wiped off, and the film was dried by heating it on a hot plate at 240°C for 50 minutes. b before and after the test * Measure , and the change (Δb * ) was calculated. In the table, b after the test * and Δb* It represents. Meanwhile, b here * Measurements were performed with a polyimide film deposited on a glass plate (glass plate + polyimide film state).

[0287] (14) Tensile modulus and tensile elongation (tensile fracture deformation)

[0288] Tensile modulus and tensile elongation (tensile fracture deformation) were measured in accordance with JIS K7161:2014 and JIS K7127:1999 using the tensile testing machine “Strograph VG-1E” manufactured by Toyo Seiki Co., Ltd. The chuck distance was 50 mm, the specimen size was 10 mm × 70 mm, and the test speed was 20 mm / min.

[0289] The tetracarboxylic acid components and diamine components used in the examples and comparative examples, and their abbreviations, are as follows.

[0290] Diamine

[0291] 3,3'-DDS: 3,3'-bis(aminophenyl)sulfone (manufactured by Seika Corporation; compound represented by formula (b-11))

[0292] BAPS: Bis[4-(4-aminophenoxy)phenyl]sulfone (manufactured by Seika Corporation; compound represented by formula (b-12))

[0293] BAPS-M: Bis[4-(3-aminophenoxy)phenyl]sulfone (manufactured by Seika Corporation; compound represented by formula (b-13))

[0294] 3,5-DABA: 3,5-diaminobenzoic acid (manufactured by Japan Pure Pharmaceutical Co., Ltd.; compound represented by formula (b-2))

[0295] X-22-9409: Amino-modified silicone oil "X-22-9409" (manufactured by Shin-Etsu Chemical Co., Ltd.; compound represented by formula (b-3))

[0296] 6FODA: 4,4'-Diamino-2,2'-Bistrifluoromethyldiphenyl ether (Manufactured by ChinaTech Chemical (Tianjin) Co., Ltd.; compound represented by formula (b-4))

[0297] Tetracarboxylic acid component

[0298] CpODA: Novonan-2-spiro-α-cyclopentanone-α'-spiro-2”-novonan-5,5”,6,6”-tetracarboxylic acid dianhydride (manufactured by JX Energy Co., Ltd.; compound represented by formula (a-1))

[0299] HPMDA: 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride (Mitsubishi Gas & Chemical Corporation; compound represented by formula (a-2))

[0300] <Cross-linking agent>

[0301] 1,3-PBO: 1,3-bis(4,5-dihydro-2-oxazolyl)benzene (Mikuni Pharmaceutical Co., Ltd.)

[0302] Others

[0303] GBL: γ-butyrolactone (Mitsubishi Chemical Corporation)

[0304] TEA: Triethylamine (manufactured by Kanto Chemical Co., Ltd.)

[0305] Example 1

[0306] 28.793 g (0.066 mol) of BAPS-M, 3.372 g (0.022 mol) of 3,5-DABA, and 125.425 g of GBL were added to a 300 mL five-neck round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a cooling tube, a thermometer, and a glass end cap, and the mixture was stirred at a rotation speed of 200 rpm under a nitrogen atmosphere at an internal temperature of 70°C to obtain a solution.

[0307] To this solution, 35.026 g (0.089 mol) of CpODA and 35.026 g of GBL were added in a lump sum, and 0.784 g of TEA was additionally added as an imidization catalyst. The mixture was heated with a mantle heater, and the temperature inside the reaction system was raised to 200°C over approximately 30 minutes. The leached components were collected, and while adjusting the rotation speed to match the increase in viscosity, the temperature inside the reaction system was maintained at 200°C and refluxed for 4 hours.

[0308] Afterwards, GBL was added to achieve a solid content concentration of 20 mass%, the temperature in the reaction system was cooled to 100°C, and the mixture was homogenized by stirring for about 1 hour. Subsequently, 0.755 g of 1,3-PBO (0.5 mol% relative to 1 mol% of 3,5-DABA) was added to 100 g of the obtained varnish and the mixture was homogenized by stirring for 30 minutes to obtain a polyimide varnish.

[0309] The obtained polyimide varnish was subsequently applied to a glass plate and a silicon wafer by spin coating and dried on a hot plate at 120°C for 15 minutes. Afterwards, the solvent was evaporated by heating at 260°C for 60 minutes in a hot air dryer under atmospheric conditions to obtain a film with a thickness of 10 μm.

[0310] Example 2

[0311] 15.007 g (0.045 mol) of 6FODA, 5.564 g (0.022 mol) of 3,3'-DDS, 6.791 g (0.045 mol) of 3,5-DABA, 13.670 g (0.011 mol) of X-22-9409, and 127.679 g of GBL were added to a 300 mL five-neck round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a cooling tube, a thermometer, and a glass end cap, and the mixture was stirred at a rotation speed of 200 rpm under a nitrogen atmosphere at an internal temperature of 70°C to obtain a solution.

[0312] To this solution, 27.368 g (0.122 mol) of HPMDA and 31.920 g of GBL were added in a lump sum, and 0.730 g of TEA was additionally added as an imidization catalyst. The mixture was heated with a mantle heater, and the temperature inside the reaction system was raised to 200°C over approximately 30 minutes. The leached components were collected, and while adjusting the rotation speed to match the increase in viscosity, the temperature inside the reaction system was maintained at 200°C and refluxed for 4 hours.

[0313] Afterwards, GBL was added to achieve a solid content concentration of 20 mass%, the temperature in the reaction system was cooled to 100°C, and the mixture was homogenized by stirring for about 1 hour. Subsequently, 1.492 g of 1,3-PBO (0.5 mol% relative to 1 mol% of 3,5-DABA) was added to 100 g of the obtained varnish, stirred for 30 minutes, and homogenized to obtain a polyimide varnish.

[0314] The obtained polyimide varnish was subsequently applied to a glass plate and a silicon wafer by spin coating and dried on a hot plate at 120°C for 15 minutes. Afterwards, the solvent was evaporated by heating at 260°C for 60 minutes in a hot air dryer under atmospheric conditions to obtain a film with a thickness of 10 μm.

[0315] Example 3

[0316] 13.853 g (0.041 mol) of 6FODA, 8.921 g (0.021 mol) of BAPS-M, 6.269 g (0.041 mol) of 3,5-DABA, 13.610 g (0.011 mol) of X-22-9409, and 127.099 g of GBL were added to a 300 mL five-neck round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a cooling tube, a thermometer, and a glass end cap, and the mixture was stirred at a rotation speed of 200 rpm under a nitrogen atmosphere at an internal temperature of 70 ℃ to obtain a solution.

[0317] To this solution, 25.436 g (0.113 mol) of HPMDA and 31.775 g of GBL were added in a lump sum, and 0.678 g of TEA was additionally added as an imidization catalyst. The mixture was heated with a mantle heater, and the temperature inside the reaction system was raised to 200°C over approximately 30 minutes. The leached components were collected, and while adjusting the rotation speed to match the increase in viscosity, the temperature inside the reaction system was maintained at 200°C and refluxed for 4 hours.

[0318] Afterwards, GBL was added to achieve a solid content concentration of 20 mass%, the temperature in the reaction system was cooled to 100°C, and the mixture was homogenized by stirring for about 1 hour. Subsequently, 1.384 g of 1,3-PBO (0.5 mol% relative to 1 mol% of 3,5-DABA) was added to 100 g of the obtained varnish, stirred for 30 minutes, and homogenized to obtain a polyimide varnish.

[0319] The obtained polyimide varnish was subsequently applied to a glass plate and a silicon wafer by spin coating and dried on a hot plate at 120°C for 15 minutes. Afterwards, the solvent was evaporated by heating at 260°C for 60 minutes in a hot air dryer under atmospheric conditions to obtain a film with a thickness of 10 μm.

[0320] Example 4

[0321] 14.512 g (0.034 mol), 8.363 g (0.034 mol), 2.552 g (0.017 mol), 6.616 g (0.005 mol), X-22-9409, and 125.448 g of GBL were added to a 300 mL five-neck round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a cooling tube, a thermometer, and a glass end cap, and the mixture was stirred at a rotation speed of 200 rpm at an internal temperature of 70°C under a nitrogen atmosphere to obtain a solution.

[0322] To this solution, 35.161 g (0.089 mol) of CpODA and 31.362 g of GBL were added in a lump sum, and 0.619 g of TEA was additionally added as an imidization catalyst. The reaction system was heated with a mantle heater to raise the temperature to 200°C over approximately 30 minutes. The leached components were collected, and the reaction system was refluxed for 4 hours while maintaining the temperature at 200°C, while adjusting the rotation speed to match the increase in viscosity.

[0323] Afterwards, GBL was added to achieve a solid content concentration of 20 mass%, the temperature in the reaction system was cooled to 100°C, and the mixture was homogenized by stirring for about 1 hour. Subsequently, 0.571 g of 1,3-PBO (0.5 mol% relative to 1 mol% of 3,5-DABA) was added to 100 g of the obtained varnish, stirred for 30 minutes, and homogenized to obtain a polyimide varnish.

[0324] The obtained polyimide varnish was subsequently applied to a glass plate and a silicon wafer by spin coating and dried on a hot plate at 120°C for 15 minutes. Afterwards, the solvent was evaporated by heating in a hot air dryer at 260°C for 60 minutes under atmospheric conditions to obtain a film with a thickness of 10 μm.

[0325] Example 5

[0326] 17.235 g (0.040 mol), 17.252 g (0.040 mol), 3.031 g (0.020 mol), 6.771 g (0.005 mol), X-22-9409, and 126.514 g of GBL were added to a 300 mL five-neck round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a cooling tube, a thermometer, and a glass end cap, and the mixture was stirred at a rotation speed of 200 rpm under a nitrogen atmosphere at an internal temperature of 70°C to obtain a solution.

[0327] To this solution, 23.486 g (0.105 mol) of HPMDA and 31.629 g of GBL were added in a lump sum, and 0.731 g of TEA was additionally added as an imidization catalyst. The reaction system was heated with a mantle heater to raise the temperature to 200°C over approximately 30 minutes. The leached components were collected, and the reaction system was refluxed for 4 hours while maintaining the temperature at 200°C, while adjusting the rotation speed to match the increase in viscosity.

[0328] Afterwards, GBL was added to achieve a solid content concentration of 20 mass%, the temperature in the reaction system was cooled to 100°C, and the mixture was homogenized by stirring for about 1 hour. Subsequently, 0.672 g of 1,3-PBO (0.5 mol% relative to 1 mol% of 3,5-DABA) was added to 100 g of the obtained varnish, stirred for 30 minutes, and homogenized to obtain a polyimide varnish.

[0329] The obtained polyimide varnish was subsequently applied to a glass plate and a silicon wafer by spin coating and dried on a hot plate at 120°C for 15 minutes. Afterwards, the solvent was evaporated by heating at 260°C for 60 minutes in a hot air dryer under atmospheric conditions to obtain a film with a thickness of 10 μm.

[0330] The above evaluation was performed on the obtained film. The results are shown in Table 1.

[0331] [Table 1]

[0332]

[0333] As shown in Table 1, the polyimide films of Examples 1 to 5 had good colorless transparency and optical isotropy, and also had excellent peelability from the substrate.

Claims

Claim 1 A polyimide resin composition comprising a polyimide resin and a crosslinking agent having at least two oxazolyl groups, wherein the polyimide resin is a polyimide resin having a constituent unit A derived from a tetracarboxylic acid dianhydride and a constituent unit B derived from a diamine, wherein constituent unit B comprises a constituent unit (B-1) derived from a diamine having a sulfonyl group in its structure and a constituent unit (B-2) derived from a compound represented by the following formula (b-2), and constituent unit (B-1) is at least one selected from the group consisting of a constituent unit (B-12) derived from a compound represented by the following formula (b-12) and a constituent unit (B-13) derived from a compound represented by the following formula (b-13). (In formula (b-2), X is a single bond, a substituted or unsubstituted alkylene group, a carbonyl group, an ether group, a group represented by the following formula (b-2-i), or a group represented by the following formula (b-2-ii); p is an integer from 0 to 2; m1 is an integer from 0 to 4; and m2 is an integer from 0 to 4. However, if p is 0, m1 is an integer from 1 to 4.) (In Equation (b-2-i), m3 is an integer from 0 to 5; in Equation (b-2-ii), m4 is an integer from 0 to 5. Meanwhile, m1+m2+m3+m4 is greater than or equal to 1, and when p is 2, each of the two Xs and the two m2~m4s are selected independently.) Claim 2 A polyimide resin composition according to claim 1, wherein the constituent unit (B-2) is a constituent unit (B-21) derived from a compound represented by the following formula (b-21). Claim 3 delete Claim 4 A polyimide resin composition according to claim 1, wherein constituent unit A comprises at least one selected from the group consisting of 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). Claim 5 A polyimide resin composition according to claim 1, wherein constituent unit B further comprises a constituent unit (B-3) derived from a compound represented by the following formula (b-3). (In Equation (b-3), Z 1 and Z 2 Each independently represents a divalent aliphatic group that may contain an oxygen atom, or a divalent aromatic group, and R 1 and R 2 Each independently represents a monovalent aromatic group or a monovalent aliphatic group, and R 3 and R 4 Each independently represents a monovalent aliphatic group, and R 5 and R 6 Each represents independently a monovalent aliphatic group or a monovalent aromatic group, m and n each represent independently an integer greater than or equal to 1, and the sum of m and n represents an integer between 2 and 1000. However, R 1 and R 2 At least one of the groups represents a monovalent aromatic group.) Claim 6 A polyimide resin composition according to claim 1, wherein constituent unit B further comprises a constituent unit (B-4) derived from a compound represented by the following formula (b-4). Claim 7 A polyimide resin composition according to claim 1, wherein the crosslinking agent is a compound comprising an aromatic ring or an aromatic heterocyclic ring to which at least two oxazolyl groups are bonded. Claim 8 A polyimide resin composition according to claim 1, wherein the crosslinking agent is a compound comprising a benzene ring to which at least two oxazolyl groups are bonded. Claim 9 A polyimide resin composition according to claim 1, wherein the crosslinking agent is 1,3-bis(4,5-dihydro-2-oxazolyl)benzene. Claim 10 A polyimide varnish formed by dissolving a polyimide resin composition described in any one of claims 1, 2, and 4 to 9 in an organic solvent. Claim 11 A polyimide film formed by crosslinking the polyimide resin in the polyimide resin composition described in any one of claims 1, 2, and 4 to 9 with the crosslinking agent.

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