Copolymer, copolymer solution, photosensitive resin composition, cured product, copolymer manufacturing method, and copolymer solution manufacturing method

Abstract

To provide a copolymer which gives a cured product excellent in solvent resistance even under a low temperature curing condition, and is suitably usable as a thermosetting resin in various applications such as a color filter.SOLUTION: A copolymer has an epoxy group-containing unit (A) having a specific structure and an acid group-containing unit (B) represented by formula (2), and has an epoxy equivalent of 20,000 or less. (In the formula (2), R5 represents a bond chain having a length of 2 atoms or more, Y represents an acid group, and a represents 0 or 1).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a copolymer, and more particularly to a copolymer capable of giving a cured product having excellent solvent resistance even under low-temperature curing conditions, a copolymer solution, a photosensitive resin composition, a cured product, a method for producing the copolymer, and a method for producing the copolymer solution. [Background technology]

[0002] Compositions containing curable resins have been widely studied for their application to various applications, such as various optical components and electric / electronic devices, including color filters, inks, printing plates, printed wiring boards, semiconductor devices, photoresists, organic insulating films, and organic protective films used in liquid crystal displays and solid-state imaging devices, and resins and resin compositions having excellent properties required for each application have been developed. In recent years, optical components and electrical and electronic devices have become smaller, thinner, and more energy-efficient, and as a result, higher performance is required for the various components used in these devices. To meet these demands, research is being conducted on curable resins, which are used as materials for various components.

[0003] Up to now, curable resins have been developed to meet various requirements. For example, Patent Document 1 describes a photosensitive resin composition containing an oligomer having a carboxyl group and a photoreactive unsaturated group in a side chain and being soluble in an alkaline aqueous solution, a compound having an epoxy group, a sensitizer, and a modified dicyandiamide. Furthermore, for example, Patent Document 2 describes a photosensitive composition containing an alkali-soluble polymer obtained by polymerizing a radical polymerizable monomer having an epoxy group or an oxetanyl group, a radical polymerizable monomer having a carboxyl group, or the like. Furthermore, for example, Patent Document 3 describes a curable polymer having an acid group, a hydroxy group, and a polymerizable unsaturated bond in the side chain, which is obtained by performing a specific modification reaction on an addition copolymer of a (meth)acrylate monomer having a glass transition temperature of 10°C or less when made into a homopolymer, or a (meth)acrylate monomer having an epoxy group or a carboxyl group, and a photosensitive polymer composition containing the curable polymer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 4-25846 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-251009 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-210892 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, various studies have been conducted on curable resins, but when conventional curable resins are used together with color materials as raw materials for color filters, for example, there is a problem that the color materials are eluted from the raw materials into cleaning solvents during the production of color filters. Therefore, further improvement in the solvent resistance of curable resins has been desired.

[0006] Furthermore, in recent years, particularly in color filter applications, the improvement in quality and expansion of applications of color liquid crystal display devices and the like have led to a strong demand for higher performance, such as higher brightness and contrast, in display panels. However, in the production of color filters, if the baking process (post-curing process) after exposure and development is performed at a high temperature above 200°C, discoloration such as yellowing occurs in the resulting cured product, preventing sufficient high coloration of the desired color. Furthermore, if the baking process is performed at a high temperature, unwanted reactions occur, producing by-products and degrading the properties of the substrate and the cured film. To suppress such unwanted reactions and efficiently obtain color filters with the desired properties, it is desirable for the curing reaction to proceed sufficiently even under relatively low heating conditions of 200°C or less. Furthermore, if the curable resin composition can be cured at a relatively low temperature, the production efficiency of color filters can also be improved. The conventional photosensitive resin composition described in Patent Document 1 requires high temperatures for resin synthesis, and there is also room for improvement in the curability of the resin.

[0007] The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a copolymer which can give a cured product having excellent solvent resistance even under low-temperature curing conditions and can be suitably used as a thermosetting resin in various applications such as color filters. [Means for solving the problem]

[0008] The present inventors have conducted extensive research into curable resins and have found that by forming a copolymer having an epoxy group-containing group and a long-chain acid group in one molecule and having an epoxy equivalent within a specific range, the crosslinking reaction proceeds well even under low-temperature curing conditions of 160°C or less, and a cured product with excellent solvent resistance can be obtained, leading to the completion of the present invention.

[0009] That is, the present invention relates to a copolymer having an epoxy group-containing structural unit (A) represented by the following general formula (1) and an acid group-containing structural unit (B) represented by the following general formula (2), and having an epoxy equivalent of 20,000 or less.

[0010] [Chemical formula] (In formula (1), R 1 represents a hydrogen atom or a methyl group. R 2 represents a direct bond or a divalent organic group. X represents an epoxy group-containing group.)

[0011] [Chemical formula]

[0012] (In formula (2), R 3 represents a hydrogen atom or a methyl group. R 4 represents a direct bond or an organic group. R 5 represents a bonding chain having a length of 2 atoms or more. Y represents an acid group. a represents 0 or 1.)

[0013] In the above copolymer, it is preferable that the structural unit (A) includes a structural unit represented by the following general formula (1-1).

[0014] [Chemical formula] (In formula (1-1), R 1 represents a hydrogen atom or a methyl group. R 6 represents a direct bond or a divalent organic group.)

[0015] In the above copolymer, it is preferable that the structural unit (B) includes a structural unit represented by the following general formula (2-1).

[0016] [Chemical formula] (In formula (2-1), R 3 represents a hydrogen atom or a methyl group. R 7 and R 8 are the same or different and represent a direct bond or an organic group. b represents 0 or 1.)

[0017] The copolymer preferably further has a ring structure in the main chain.

[0018] The copolymer preferably further contains a structural unit derived from a monomer having 5 to 20 carbon atoms in the longest side chain or a monomer having a ring structure in the side chain.

[0019] The present invention is also a copolymer solution characterized by containing the above-described copolymer and a protic polar solvent.

[0020] The copolymer solution preferably further contains an acid compound having a pKa of 4.2 or less.

[0021] The copolymer solution preferably further contains a phosphate derivative.

[0022] The copolymer solution preferably further contains a basic compound.

[0023] The present invention is also a photosensitive resin composition characterized by containing the above-described copolymer or copolymer solution, a polymerizable compound, and a photopolymerization initiator.

[0024] The photosensitive resin composition preferably further contains a coloring material.

[0025] The photosensitive resin composition is preferably for negative type.

[0026] The present invention is also a cured product of the above-described copolymer, the above-described copolymer solution, or the above-described photosensitive resin composition.

[0027] The present invention is also a method for producing a copolymer, including a step of polymerizing a monomer component containing an epoxy group-containing monomer represented by the following formula (a) and a hydroxyl group-containing monomer represented by the following formula (b1), and a step of reacting the polymer obtained in the above polymerization step with an acid group-containing compound represented by the following formula (b2) or formula (b3).

[0028] [ka] (In formula (a), R 1 represents a hydrogen atom or a methyl group. 2 represents a direct bond or a divalent organic group. X represents an epoxy group-containing group.

[0029] [ka] (In formula (b1), R 3 represents a hydrogen atom or a methyl group. 4 represents a direct bond or an organic group.

[0030] [ka] (In formula (b2), R 5 represents a bonded chain of two or more atoms in length. Y represents an acid group.

[0031] [ka] (In formula (b3), R 5 represents a bonded chain of two or more atoms in length.)

[0032] The present invention also provides a method for producing a copolymer solution, comprising the steps of: polymerizing a monomer component containing an epoxy group represented by the following formula (a) and a hydroxyl group-containing monomer represented by the following formula (b1); reacting the polymer obtained in the polymerization step with an acid group-containing compound represented by the following formula (b2) or (b3) in the presence of a basic compound; and adding an acid compound having a pKa of 4.2 or less and a protic polar solvent.

[0033] [ka] (In formula (a), R 1 represents a hydrogen atom or a methyl group. 2represents a direct bond or a divalent organic group. X represents an epoxy group-containing group.)

[0034]

Chemical formula

[0035]

Chemical formula

[0036]

Chemical formula

Advantages of the Invention

[0037] The copolymer of the present invention can provide a cured product excellent in solvent resistance even under relatively low curing conditions of 160°C or lower. The copolymer of the present invention is suitably used for various applications such as various optical members used in liquid crystal, organic EL, quantum dot, and micro LED liquid crystal display devices, solid-state imaging devices, touch panel display devices, and constituent members of electrical and electronic devices, etc.

Modes for Carrying Out the Invention

[0038] The present invention will be described in detail below. In addition, a combination of two or more of the individual preferred forms of the present invention described below is also a preferred form of the present invention. In the present specification, “(meth)acrylic acid” means “acrylic acid and / or methacrylic acid”, and “(meth)acrylate” means “acrylate and / or methacrylate”.

[0039] 1. Copolymer The copolymer of the present invention has an epoxy group-containing structural unit (A) represented by the following general formula (1) and an acid group-containing structural unit (B) represented by the following general formula (2), and is characterized in that the epoxy equivalent is 20,000 or less.

[0040] [Chemical formula] (In formula (1), R 1 represents a hydrogen atom or a methyl group. R 2 represents a direct bond or a divalent organic group. X represents an epoxy group-containing group.)

[0041] [Chemical formula] (In formula (2), R 3 represents a hydrogen atom or a methyl group. R 4 represents a direct bond or an organic group. R 5 represents a bonding chain having a length of 2 atoms or more. Y represents an acid group. a represents 0 or 1.)

[0042] The copolymer of the present invention can give a cured product having excellent solvent resistance even under relatively low-temperature curing conditions of 160°C or lower (preferably about 90°C). This is because it has an epoxy group and an acid group, and the acid group is a long-chain acid located relatively far from the main chain. Therefore, the acid group reacts very easily with the epoxy group, and the cross-linking reaction proceeds even at a relatively low temperature to form a strong cured film. It is presumed that when the side chain of the acid group-containing structural unit becomes longer, the glass transition temperature becomes lower than that of the structural units of acrylic acid or methacrylic acid, and the higher molecular side chain becomes more flexible, making the above cross-linking reaction proceed easily at low temperatures.

[0043] The copolymer of the present invention has the above-mentioned epoxy group-containing structural unit (A) and acid group-containing structural unit (B), and has an epoxy equivalent (g / equivalent) of 20,000 or less. If the epoxy equivalent exceeds 20,000, curing may be insufficient, and solvent resistance may decrease. The epoxy equivalent of the copolymer of the present invention is preferably 10,000 or less, more preferably 8,000 or less, even more preferably 5,000 or less, even more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less. Furthermore, from the viewpoint of storage stability, the epoxy equivalent is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more. The epoxy equivalent can be determined by dividing the copolymer solid content by the number of moles of epoxy groups contained in the copolymer. Alternatively, the epoxy equivalent can be determined by a method in accordance with JIS K7236:2001.

[0044] <Structural unit (A)> The copolymer of the present invention has an epoxy group-containing structural unit (A) represented by the above general formula (1). In the above general formula (1), R 1 represents a hydrogen atom or a methyl group. R 2 represents a direct bond or a divalent organic group. Examples of the organic group include linear or cyclic saturated or unsaturated hydrocarbon groups, -O-, -CO-, -COO-, -NH-, -S-, -SO-, -SO2-, and divalent groups formed by combinations of these. Examples of the hydrocarbon group include divalent aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The aliphatic hydrocarbon group may be linear or branched, and examples thereof include alkylene groups such as methylene, ethylene, trimethylene, propylene, ethylidene, propylidene, and isopropylidene groups, as well as vinylene, propenylene, and vinylidene groups. Examples of the alicyclic hydrocarbon group include cycloalkylene groups such as 1,2-cyclopentylene, 1,2-cyclohexylene, cyclopentylidene, and cyclohexylidene. Examples of the aromatic hydrocarbon group include a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a benzylidene group, a cinnamylidene group, and a biphenylylene group.

[0045] The hydrocarbon group may have at least one atom substituted with an oxygen atom, a nitrogen atom, or a sulfur atom. The hydrocarbon group may also have a substituent. Examples of the substituent include a hydroxyl group, an alkoxy group, an alkyl group, an allyl group, an aryl group, and a halogen atom. The substituent may also have a further substituent.

[0046] Specific examples of the divalent organic group include -R-, -CO-, -CO-R-, -R-CO-R'-, -COO-, -COO-R-, -R-COO-R'-, -OR-, and -RO-R'- (wherein R and R' are the same or different and represent the divalent hydrocarbon group).

[0047] The divalent organic group preferably has 0 to 10 atoms, more preferably 1 to 5 atoms, and even more preferably 2 to 4 atoms.

[0048] Among them, R 2 is preferably -R-, -COO-, or -COO-R-, and more preferably -COO- or -COO-R- (R represents a hydrocarbon group having 1 to 4 carbon atoms which may have a substituent, and preferably represents an alkylene group having 1 to 2 carbon atoms).

[0049] X represents a group containing an epoxy group. In the present specification, the epoxy group-containing group is a group containing an oxirane ring (epoxy group), such as a group in which the oxirane ring is bonded to carbon like a glycidyl group, or a group containing an ether bond or an ester bond like a glycidyl ether group and a glycidyl ester group, and an alicyclic epoxy group containing an epoxycyclohexane ring, etc. are included. As the epoxy group-containing group, for example, groups represented by the following formulas (x1) to (x4) are preferably mentioned.

[0050]

Chemical formula

[0051] In the formulas, n is an integer from 0 to 10, preferably an integer from 0 to 4, and more preferably an integer from 0 to 2. m is an integer from 1 to 10, preferably an integer from 2 to 8, and more preferably an integer from 3 to 6. Among them, as X, from the viewpoint of reactivity, (x1) is preferable, and (x1) with n = 1 is more preferable.

[0052] The above structural unit (A) is preferably a structural unit (A-1) represented by the following general formula (1-1) in terms of further improving the solvent resistance.

[0053]

Chemical formula

[0054] In the above general formula (1-1), R 1 represents a hydrogen atom or a methyl group. Among them, R 1 is preferably a methyl group. R 6 As the divalent organic group represented by, for example, the above-mentioned R 2Groups similar to the divalent organic group represented by R 6 The number of carbon atoms of the divalent organic group represented by is preferably from 0 to 10, more preferably from 1 to 4, and still more preferably from 1 to 2.

[0055] Among them, R 6 As the divalent organic group represented by, a divalent aliphatic hydrocarbon group is preferable, a divalent aliphatic hydrocarbon group having no substituent is more preferable, and a methylene group is preferable.

[0056] The copolymer having the above structural unit (A) can be obtained by polymerizing a monomer component containing a monomer capable of introducing the above structural unit (A). Examples of the monomer capable of introducing the above structural unit (A) include, for example, a compound represented by the following formula (a).

[0057]

Chemical formula

[0058] Specific examples of the monomer capable of introducing the above structural unit (A) include, for example, glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, β-ethylglycidyl (meth) acrylate, vinylbenzyl glycidyl ether, allyl glycidyl ether, (3,4-epoxycyclohexyl) methyl (meth) acrylate, vinylcyclohexene oxide and the like. Among them, glycidyl (meth) acrylate and (3,4-epoxycyclohexyl) methyl (meth) acrylate are preferable, glycidyl (meth) acrylate is more preferable, and glycidyl methacrylate is still more preferable in terms of suppressing side reactions and expecting an improvement in storage stability.

[0059] The copolymer of the present invention may have one or more types of the above structural unit (A).

[0060] In the copolymer of the present invention, the content of the structural unit (A) is preferably 0.1 to 50% by mass, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, relative to 100% by mass of all structural units, and more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0061] <Structural unit (B)> The copolymer of the present invention further has an acid group-containing structural unit (B) represented by the above general formula (2).

[0062] In the above general formula (2), R 3 represents a hydrogen atom or a methyl group. R 4 represents a direct bond or an organic group. 4 The organic group represented by the formula (I) is the above-mentioned R 2 and the like. R 4 The organic group represented by the formula (I) preferably has 1 to 10 atoms, more preferably 1 to 8 atoms, and even more preferably 2 to 5 atoms. R 4 The organic group represented by the formula (I) is preferably a divalent organic group which may have a substituent, more preferably a divalent organic group containing an ester bond, more preferably -CO-OR- (wherein R represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms), or -CO-OR(-O-CO-R')- (wherein R represents a linear or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms, and R' represents a monovalent aliphatic hydrocarbon group having 1 to 3 carbon atoms), and even more preferably -CO-OR- (wherein R represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms).

[0063] R 5represents a bonding chain having a length of two or more atoms. The length of the bonding chain refers to the number of atoms connected in the main chain of the bonding chain, and does not include the number of atoms constituting the side chain of the bonding chain. Specifically, examples of bonding chains having a length of two atoms include -CH2-CH2-, -C(CH3)-CH2-, -C(CH3)-C(CH3)-, -CH2-O-, -O-CH2-, -CO-O-, and -CH=CH-, while examples of bonding chains having a length of three atoms include -CH2-CH2-CH2-, -CH2-O-CH2-, -CO-O-CH2-, -CH2-O-CO-, and -CH=CH-CH2-. A bonding chain length of 0 is synonymous with a "direct bond."

[0064] R 5 The length of the bond chain represented by the formula (I) is preferably 10 or less, more preferably 5 or less, and most preferably 2, in terms of superior crosslinkability.

[0065] The linking chain is preferably a divalent organic group. Examples of the divalent organic group include the above-mentioned R 2 Examples of the divalent organic group include the same groups as those represented by the following formula: Among these, the organic group is preferably -R-, -OR-, -ORO-, -CO-R-, or -ORO-CO-R'- (R and R' are the same or different and represent divalent hydrocarbon groups which may have a substituent), more preferably -R-, -OR-, or -ORO-CO-R'- (R and R' are the same or different and represent divalent aliphatic hydrocarbon groups which may have a substituent), and even more preferably an ethylene group.

[0066] Y represents an acid group. Examples of the acid group include functional groups that undergo a neutralization reaction with alkaline water, such as a carboxyl group, a phenolic hydroxyl group, a carboxylic anhydride group, a phosphoric acid group, and a sulfonic acid group. Only one of these may be present, or two or more may be present. Among these, a carboxyl group or a carboxylic anhydride group is preferred, and a carboxyl group is more preferred. It may also have two or more acid groups.

[0067] a represents 0 or 1. In terms of further improved solvent resistance, a is preferably 1.

[0068] As the above structural unit (B), the structural unit (B-1) represented by the following general formula (2-1) is preferably exemplified.

[0069]

Chemical formula

[0070] In the above general formula (2-1), R 3 represents a hydrogen atom or a methyl group. R 3 is preferably a methyl group in terms of good heat resistance and developability of the polymer. R 7 and R 8 Examples of the organic group represented by include the above-mentioned divalent organic groups, etc. Among them, R 7 is preferably a divalent hydrocarbon group which may have a substituent, more preferably a divalent aliphatic hydrocarbon group which may have a substituent, and still more preferably an alkylene group. R 8 is preferably a divalent hydrocarbon group which may have a substituent, more preferably a divalent aliphatic hydrocarbon group which may have a substituent, and still more preferably an alkylene group.

[0071] R 7 and R 8 The number of carbon atoms of the organic group represented by is preferably 1 to 10, more preferably 1 to 5, and still more preferably 1 to 3.

[0072] b represents 0 or 1, but in terms of further improved solvent resistance, b is preferably 1.

[0073] The copolymer having the above structural unit (B) can be obtained by polymerizing a monomer component containing a monomer capable of introducing the above structural unit (B), or by reacting a base polymer obtained by polymerizing a monomer component containing a hydroxyl group-containing monomer with an acid group-containing compound.

[0074] Examples of the monomer capable of introducing the above structural unit (B) include long-chain unsaturated monocarboxylic acids in which the chain is extended between an unsaturated group and a carboxyl group, such as β-carboxyethyl (meth)acrylate, succinic acid mono(2-acryloyloxyethyl), and succinic acid mono(2-methacryloyloxyethyl).

[0075] Examples of the hydroxyl group-containing monomer include compounds represented by the following formula (b1).

[0076] [Chemical formula] (In the formula, R 3 and R 4 are the same as R 3 and R 4 in the above general formula (2), respectively.)

[0077] Specific examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2,3-hydroxypropyl (meth)acrylate; mono(meth)acrylates of polyols such as glycerin mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, mono(meth)acrylate of pentaerythritol, ditrimethylolpropane mono(meth)acrylate, and dipentaerythritol mono(meth)acrylate; and hydroxyalkylacrylamides such as N-hydroxyethylacrylamide.

[0078] Examples of the acid group-containing compound include compounds represented by the following formula (b2) or (b3).

[0079] [ka] (In the formula, R 5 and Y is R in the above general formula (2). 5 and Y, respectively.)

[0080] [ka] (In the formula, R 5 is R in the above general formula (2). 5 is the same as

[0081] Specific examples of the acid group-containing compound include carboxylic acids such as succinic acid, maleic acid, phthalic acid, tetrahydrophthalic acid, and trimellitic acid; and carboxylic acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, itaconic anhydride, and trimellitic anhydride. Among these, carboxylic acid anhydrides are preferred, and succinic anhydride is more preferred, in view of higher addition reactivity.

[0082] A specific method for obtaining a copolymer having the structural unit (B) will be described in detail in the method for producing a polymer below.

[0083] The copolymer of the present invention may have one or more types of structural units (B).

[0084] In the copolymer of the present invention, the content of the structural unit (B) is preferably 0.1 to 50% by mass, more preferably 0.2% by mass or more, and even more preferably 1% by mass or more, relative to 100% by mass of all structural units, and more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0085] <Structural unit (C)> The copolymer of the present invention is preferably a copolymer having a ring structure in the main chain. That is, the above copolymer preferably further has a structural unit (C) having a ring structure in the main chain. When the above copolymer is a polymer having a ring structure in the main chain, a cured product excellent in heat resistance can be obtained. Examples of the above ring structure include an imide ring, a tetrahydropyran ring, a tetrahydrofuran ring, a lactone ring and the like. By polymerizing a monomer component containing a monomer capable of introducing a ring structure into the main chain, a copolymer having the above structural unit (C) can be obtained.

[0086] Examples of the monomer capable of introducing a ring structure into the main chain include a monomer having a double bond-containing ring structure in the molecule, a monomer that undergoes cyclopolymerization to form a polymer having a ring structure in the main chain, and a monomer that forms a ring structure after polymerization. From the viewpoints of good heat resistance, hardness, colorant dispersibility, etc., specifically, at least one monomer selected from the group consisting of N-substituted maleimide monomers, dialkyl-2,2'-(oxydimethylene) diacrylate monomers, and α-(unsaturated alkoxyalkyl) acrylate monomers is preferably mentioned. Among them, N-substituted maleimide monomers are preferred in terms of even better solvent resistance.

[0087] Examples of the above N-substituted maleimide monomers include N-cyclohexyl maleimide, N-phenyl maleimide, N-methyl maleimide, N-ethyl maleimide, N-isopropyl maleimide, N-t-butyl maleimide, N-dodecyl maleimide, N-benzyl maleimide, N-naphthyl maleimide and the like, and one or more of these can be used. Among them, from the viewpoint of heat resistance, N-phenyl maleimide, N-benzyl maleimide, and N-cyclohexyl maleimide are preferred, and N-benzyl maleimide is more preferred.

[0088] Examples of the N-benzylmaleimide include benzylmaleimide; alkyl-substituted benzylmaleimides such as p-methylbenzylmaleimide and p-butylbenzylmaleimide; phenolic hydroxyl group-substituted benzylmaleimides such as p-hydroxybenzylmaleimide; and halogen-substituted benzylmaleimides such as o-chlorobenzylmaleimide, o-dichlorobenzylmaleimide and p-dichlorobenzylmaleimide.

[0089] Examples of the dialkyl-2,2'-(oxydimethylene) diacrylate monomer include dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, diethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, di(n-propyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(isopropyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(n-butyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, and di(isobutyl)-2,2'-[oxybis(methylene)]bis-2-propenoate. di(t-butyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(t-amyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(stearyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(lauryl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(2-ethylhexyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, etc. Among these, dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate is more preferred from the viewpoints of transparency, dispersibility, ease of industrial availability, etc.

[0090] Examples of the α-(unsaturated alkoxyalkyl)acrylate monomer include α-(allyloxymethyl)acrylate monomers. Specific examples of the α-(allyloxymethyl)acrylate monomer include α-allyloxymethylacrylic acid; methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, i-propyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, s-butyl α-allyloxymethylacrylate, t-butyl α-allyloxymethylacrylate, n-amyl α-allyloxymethylacrylate, s-amyl α-allyloxymethylacrylate, t-amyl α-allyloxymethylacrylate, n-hexyl α-allyloxymethylacrylate, s-hexyl α-allyloxymethylacrylate, n-heptyl α-allyloxymethylacrylate, n-octyl α-allyloxymethylacrylate, s-octyl α-allyloxymethylacrylate, and α-allyloxymethylacrylate. alkyl-(α-allyloxymethyl)acrylate monomers such as t-octyl α-allyloxymethylacrylate, 2-ethylhexyl α-allyloxymethylacrylate, capryl α-allyloxymethylacrylate, nonyl α-allyloxymethylacrylate, decyl α-allyloxymethylacrylate, undecyl α-allyloxymethylacrylate, lauryl α-allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, pentadecyl α-allyloxymethylacrylate, cetyl α-allyloxymethylacrylate, heptadecyl α-allyloxymethylacrylate, stearyl α-allyloxymethylacrylate, nonadecyl α-allyloxymethylacrylate, eicosyl α-allyloxymethylacrylate, ceryl α-allyloxymethylacrylate, and melissyl α-allyloxymethylacrylate;Alkoxyalkyl-(α-allyloxymethyl)acrylate monomers such as methoxyethyl α-allyloxymethyl acrylate, methoxyethoxyethyl α-allyloxymethyl acrylate, methoxyethoxyethoxyethyl α-allyloxymethyl acrylate, 3-methoxybutyl α-allyloxymethyl acrylate, ethoxyethyl α-allyloxymethyl acrylate, ethoxyethoxyethyl α-allyloxymethyl acrylate, phenoxyethyl α-allyloxymethyl acrylate, and phenoxyethoxyethyl α-allyloxymethyl acrylate;2-Hydroxyethyl α-allyloxymethylacrylate, 2-hydroxypropyl α-allyloxymethylacrylate, 4-hydroxybutyl α-allyloxymethylacrylate, 2-fluoroethyl α-allyloxymethylacrylate, 2,2-difluoroethyl α-allyloxymethylacrylate, 2-chloroethyl α-allyloxymethylacrylate, 2,2-dichloroethyl α-allyloxymethylacrylate, 2-bromoethyl α-allyloxymethylacrylate, 2,2-dibromoethyl α-allyloxymethylacrylate, vinyl α-allyloxymethylacrylate, allyl α-allyloxymethylacrylate, methallyl α-allyloxymethylacrylate, crotyl α-allyloxymethylacrylate, propargyl α-allyloxymethylacrylate, cyclopentyl α-allyloxymethylacrylate, cyclohexyl α-allyloxymethylacrylate, 4-methylcyclohexyl α-allyloxymethylacrylate, 4-t-butylcyclohexyl α-allyloxymethylacrylate, tricyclodecanyl α-allyloxymethylacrylate, isobornyl α-allyloxymethylacrylate, adamantyl α-allyloxymethylacrylate, dicyclopentadienyl α-allyloxymethylacrylate, phenyl α-allyloxymethylacrylate, methylphenyl α-allyloxymethylacrylate, dimethylphenyl α-allyloxymethylacrylate, trimethylphenyl α-allyloxymethylacrylate, 4-t-butylphenyl α-allyloxymethylacrylate, benzyl α-allyloxymethylacrylate, diphenylmethyl α-allyloxymethylacrylate, diphenylethyl α-allyloxymethylacrylate, triphenylmethyl α-allyloxymethylacrylate, cinnamyl α-allyloxymethylacrylate, naphthyl α-allyloxymethylacrylate, anthranyl α-allyloxymethylacrylate; and the like. Among them, alkyl-(α-allyloxymethyl)acrylate monomers are preferred. As the above alkyl-(α-allyloxymethyl)acrylate monomers, methyl α-allyloxymethylacrylate (also referred to as methyl-(α-allyloxymethyl)acrylate) is particularly preferred from the viewpoints of transparency, dispersibility, ease of industrial availability, etc.;

[0091] The above-mentioned α-(unsaturated alkoxyalkyl)acrylate can be produced, for example, by the production method disclosed in WO 2010 / 114077.

[0092] Another preferred example of a monomer capable of introducing a ring structure into the main chain is a 2-(hydroxyalkyl)acrylic acid alkyl ester, which can react with (meth)acrylic acid to form a lactone ring structure in the main chain.

[0093] Examples of the 2-(hydroxyalkyl)acrylic acid alkyl ester include 2-(1-hydroxyalkyl)acrylic acid alkyl esters and 2-(2-hydroxyalkyl)acrylic acid alkyl esters. Specific examples include 2-(1-hydroxymethyl)methyl acrylate, 2-(1-hydroxymethyl)ethyl acrylate, 2-(1-hydroxymethyl)isopropyl acrylate, 2-(1-hydroxymethyl)n-butyl acrylate, 2-(1-hydroxymethyl)t-butyl acrylate, and 2-ethylhexyl 2-(1-hydroxymethyl)acrylate. Among these, 2-(1-hydroxymethyl)methyl acrylate and 2-(1-hydroxymethyl)ethyl acrylate are preferred. These may be used alone or in combination of two or more.

[0094] The copolymer may have one or more types of structural units (C).

[0095] In the copolymer, the content of the structural unit (C) is preferably 0.1 to 50% by mass, more preferably 0.2% by mass or more, and even more preferably 1% by mass or more, relative to 100% by mass of all structural units, and more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0096] <Structural unit (D)> In addition to the structural units (A), (B), and (C) described above, the copolymer may further have other structural units (D). Examples of the structural unit (D) include structural units derived from, for example, in addition to the above-described hydroxyl group-containing monomers, acid group-containing monomers other than the above-described long-chain unsaturated monocarboxylic acids, (meth)acrylic acid ester monomers, monomers having a group that generates an acid group, and other copolymerizable monomers.

[0097] Examples of the acid group-containing monomer include unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, cinnamic acid, and vinylbenzoic acid; unsaturated polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid; unsaturated acid anhydrides such as maleic anhydride and itaconic anhydride; phosphate group-containing unsaturated compounds such as Light Ester P-1M (manufactured by Kyoeisha Chemical Co., Ltd.); and the like.

[0098] Examples of the (meth)acrylic acid ester monomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, n-amyl (meth)acrylate, s-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and dicyclopentaerythritol (meth)acrylate. nyl, dicyclopentenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, 1,4-dioxaspiro[4,5]dec-2-yl methacrylic acid, (meth)acryloylmorpholine, 4-(meth)acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2-methyl-2-cyclohexyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2,2-dimethyl-1,3-dioxolane, and the like.

[0099] The monomer having a group that generates an acid group includes a compound having a group that generates an acid group by heat or acid and a polymerizable double bond. Examples of the polymerizable double bond include a (meth)acryloyl group, a vinyl group, an allyl group, and a methallyl group. Examples of the group that generates an acid group by heat or an acid include a tertiary carbon-containing group, a group in which an acid group is blocked by a vinyl ether compound, a group in which a phenolic hydroxyl group is protected by a protecting group such as a t-butyl group or an acetyl group, and the like.

[0100] As the above-mentioned tertiary carbon-containing group, preferably, -COO * R a (R a represents a monovalent organic group, and the carbon atom bonded to O * is a tertiary carbon atom.) The group represented by the group is mentioned. By heating, the O-C bond between -COO * and R a is cleaved, and a carboxyl group is generated.

[0101] In the above -COO * R a of R a represents a monovalent organic group, and the carbon atom bonded to O * is a tertiary carbon atom. The tertiary carbon atom means a carbon atom to which three other carbon atoms are bonded.

[0102] Examples of the above monovalent organic group preferably include a monovalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 91 carbon atoms. The above organic group may have a substituent. R a The number of carbon atoms is more preferably 1 to 50 carbon atoms, still more preferably 1 to 35 carbon atoms, still more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and most preferably 1 to 9 carbon atoms.

[0103] R a is preferably represented by -C(R b )(R c )(R d ). In this case, R b , R c , and R dare preferably the same or different and are hydrocarbon groups having 1 to 30 carbon atoms. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, may have a cyclic structure, or may have a substituent. b , R c , and R d may be linked to each other at their terminal sites to form a cyclic structure.

[0104] In the tertiary carbon-containing group, it is preferable that at least one of the adjacent carbon atoms of the tertiary carbon atom is bonded to a hydrogen atom. a But -C(R b )(R c )(R d ), R b , R c and R d It is preferable that at least one of the groups contains a carbon atom having one or more hydrogen atoms, and that the carbon atom is bonded to a tertiary carbon atom. Above R b , R c and R d are the same or different and are preferably saturated hydrocarbon groups having 1 to 15 carbon atoms, more preferably saturated hydrocarbon groups having 1 to 10 carbon atoms, even more preferably saturated hydrocarbon groups having 1 to 5 carbon atoms, and particularly preferably saturated hydrocarbon groups having 1 to 3 carbon atoms. Above R a is preferably a t-butyl group or a t-amyl group.

[0105] Preferable examples of the tertiary carbon-containing monomer include t-butyl (meth)acrylate and t-amyl (meth)acrylate.

[0106] Examples of the group in which the acid group is blocked with a vinyl ether compound include groups in which a vinyl ether compound is bonded to the above-mentioned acid group such as a carboxyl group. Examples of the vinyl ether compound include aliphatic vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, i-propyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, and cyclohexyl vinyl ether; and cyclic ether compounds such as dihydropyran that can generate a vinyl ether upon ring-opening. Among the above vinyl ether compounds, dihydropyran is preferred because the protecting group is easily removed at a lower temperature.

[0107] The group in which the acid group is blocked with dihydropyran is preferably a group represented by the following formula:

[0108] [ka]

[0109] The above-mentioned group in which a phenolic hydroxyl group is protected by a protecting group such as a t-butyl group or an acetyl group is preferably a group represented by the following formula:

[0110] [ka] (In the formula, n represents the number of substituents and is an integer of 1 to 5.)

[0111] The group represented by the above formula is reacted, for example, in a solvent in the presence of an acid catalyst such as hydrochloric acid or sulfuric acid at a temperature of 50 to 150° C. for 1 to 30 hours, whereby the protecting group is eliminated and an acid group is generated.

[0112] Specific examples of the monomer having a group represented by the above formula include monomers in which the hydroxyl group of an aromatic vinyl compound having a phenolic hydroxyl group, such as p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, or o-isopropenylphenol, is protected with a t-butyl group or an acetyl group.

[0113] Among these, the monomer having a group in which the acid group is blocked with dihydropyran is preferred as the monomer having the group that generates the acid group, since the acid group can be generated at a lower temperature.

[0114] Examples of the other copolymerizable monomer include one or more of the following compounds: (Meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, and N-isopropylacrylamide; macromonomers having a (meth)acryloyl group at one end of the polymer molecular chain, such as polystyrene, polymethyl(meth)acrylate, polyethylene oxide, polypropylene oxide, polysiloxane, polycaprolactone, and polycaprolactam; conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate; aromatic vinyls such as styrene, vinyl toluene, α-methylstyrene, xylene, methoxystyrene, and ethoxystyrene; methyl vinyl ether, ethyl vinyl ether vinyl ethers such as propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, 2-hydroxyethyl vinyl ether, and 4-hydroxybutyl vinyl ether; N-vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinylmorpholine, and N-vinylacetamide; and unsaturated isocyanates such as isocyanatoethyl (meth)acrylate and allyl isocyanate.

[0115] Among them, as the monomer that provides the above structural unit (D), for example, by copolymerizing a monomer having an amide group such as the above (meth)acrylamides, an addition reaction can be carried out without using a basic catalyst such as an amine, and the storage stability of the copolymer can be improved. Also, when using a monomer having an amine group such as N,N-dimethylaminoethyl (meth)acrylate or N,N-diethylaminoethyl (meth)acrylate, an addition reaction can be carried out without using a catalyst, and the storage stability of the copolymer can be improved.

[0116] Further, as the monomer that provides the above structural unit (D), it is preferable to use a monomer with a long side chain or a monomer with a large steric hindrance in terms of suppressing gelation and having good storage stability. As the monomer with a long side chain, those having 5 to 20 atoms in the longest side chain of the monomer are preferable, those having 6 to 20 atoms are more preferable, and those having 7 to 10 atoms are even more preferable. The above side chain may be linear or branched. A specific example of the monomer with a long side chain is preferably 2-ethylhexyl (meth)acrylate.

[0117] As the monomer with a large steric hindrance, those having a ring structure in the side chain are preferably mentioned. For example, those having structures such as cyclohexyl, bicyclo, phenyl, biphenyl, dicyclopentanyl, furan, pyran, piperidine, etc. are mentioned. Specific examples of the monomer with a large steric hindrance include, for example, vinyltoluene, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, phenoxyethyl (meth)acrylate, (meth)acrylic acid, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, tricyclodecanyl (meth)acrylate, isobornyl (meth)acrylate, pentamethylpiperidinyl (meth)acrylate, etc. Among them, dicyclopentanyl (meth)acrylate, vinyltoluene, benzyl (meth)acrylate, and cyclohexyl (meth)acrylate are preferable.

[0118] Among them, the above copolymer preferably has a structural unit derived from at least one monomer selected from the group consisting of vinyltoluene, 2-ethylhexyl (meth)acrylate, and dicyclopentanyl (meth)acrylate in that the storage stability can be further improved. Further, when the above copolymer has a structural unit derived from 2-ethylhexyl (meth)acrylate, the glass transition temperature of the copolymer can be lowered and the developability can be improved.

[0119] The above copolymer may have one or more structural units (D).

[0120] In the above copolymer, the content ratio of the above structural unit (D) is preferably 0.1 to 50% by mass, more preferably 0.2% by mass or more, still more preferably 1% by mass or more, and more preferably 45% by mass or less, still more preferably 40% by mass or less, based on 100% by mass of all the structural units.

[0121] The acid value of the above copolymer is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, still more preferably 30 mgKOH / g or more. Also, it is preferably 300 mgKOH / g or less, more preferably 250 mgKOH / g or less, still more preferably 200 mgKOH / g or less, and even more preferably 100 mgKOH / g or less. The above acid value is a value obtained by measurement by a neutralization titration method using a potassium hydroxide (KOH) solution, and is the acid value per 1 g of the polymer solid content.

[0122] The weight average molecular weight of the above copolymer is preferably 2000 or more, more preferably 3000 or more, still more preferably 4000 or more. Also, it is preferably 250000 or less, more preferably 100000 or less, still more preferably 50000 or less, and even more preferably 20000 or less. The weight average molecular weight of the above copolymer can be measured by gel permeation chromatography (GPC), specifically, it can be measured by the method described in the examples.

[0123] The above copolymer may have a polymerizable double bond (carbon-carbon double bond) in the side chain. By having a polymerizable double bond in the side chain, the photocurability of the copolymer can be improved. Examples of the above polymerizable double bond include those described above, and among them, a (meth)acryloyl group is preferable.

[0124] When the above copolymer has a polymerizable double bond in the side chain, the double bond equivalent of the above copolymer is preferably 200 to 20000 g / equivalent. The above double bond equivalent is more preferably 250 to 15000 g / equivalent, still more preferably 300 to 10000 g / equivalent, and still more preferably 300 to 4000 g / equivalent in terms of improved curability.

[0125] The above double bond equivalent is the mass of the solid content of the polymer solution per 1 mol of the double bond of the above copolymer. The mass of the solid content of the above polymer solution is the sum of the mass of the monomer components constituting the above copolymer and the mass of the polymerization inhibitor. The above double bond equivalent can be obtained by dividing the mass (g) of the polymer solid content of the polymer solution by the amount (mol) of the double bond of the copolymer. The amount of the double bond of the above copolymer can be determined from the amounts of the monomer containing an acid group used in the polymerization and the compound having a polymerizable double bond. It can also be measured using various analyses such as titration, elemental analysis, NMR, IR, etc. and differential scanning calorimetry. For example, it may be calculated by measuring the number of ethylenic double bonds contained per 1 g of the copolymer in accordance with the iodine value test method described in JIS K 0070:1992.

[0126] <Method for Producing Copolymer> As a method for producing the copolymer of the present invention, any method can be used without particular limitation as long as it can obtain a copolymer having at least the above structural unit (A) and structural unit (B) and having an epoxy equivalent within a predetermined range. For example, a method of polymerizing a monomer component containing monomers capable of introducing each of the above structural units, a method of polymerizing a monomer component to obtain a base polymer, and subjecting the groups of the base polymer to an addition reaction with other compounds to obtain a polymer having a predetermined structural unit, and the like can be mentioned.

[0127] The method of polymerizing the above monomer component is not particularly limited, and usually used techniques such as bulk polymerization, solution polymerization, and emulsion polymerization can be used. Among them, solution polymerization is preferable in terms of being industrially advantageous and easy to adjust the structure such as molecular weight. In addition, as the polymerization mechanism of the above monomer component, a polymerization method based on a mechanism such as radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization can be used, but a polymerization method based on a radical polymerization mechanism is preferable in terms of industrial advantages. In addition, the molecular weight of the polymer obtained by polymerizing the above monomer component can be controlled by appropriately adjusting the amount and type of the polymerization initiator, the polymerization temperature, and the type and amount of the chain transfer agent.

[0128] Examples of the above polymerization initiator include peroxides and azo compounds that are usually used as polymerization initiators. Examples of the above chain transfer agent include compounds having a mercapto group such as alkyl mercaptans, mercapto carboxylic acids, and mercapto carboxylic acid esters that are usually used as chain transfer agents. These may be used alone or in combination of two or more. In addition, the addition amounts thereof can be appropriately set from known methods.

[0129] Examples of solvents used in the polymerization include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; chloroform; dimethyl sulfoxide; and dimethyl carbonate. These solvents may be used alone or in combination of two or more.

[0130] The polymerization concentration when polymerizing the monomer composition (reaction liquid) containing the above-mentioned monomer components is preferably 5 to 90 mass %, more preferably 5 to 70 mass %, and even more preferably 10 to 60 mass %. The polymerization concentration is the mass % of the monomers used relative to 100 mass % of the reaction liquid.

[0131] Regarding the polymerization conditions, the polymerization temperature may be appropriately set depending on the type and amount of the monomer used, the type and amount of the polymerization initiator, etc., and is, for example, preferably 50 to 130° C., more preferably 60 to 120° C. Similarly, the polymerization time can also be appropriately set, and is, for example, preferably 1 to 5 hours, more preferably 2 to 4 hours.

[0132] A preferred example of a method for producing the copolymer includes a step (1) of polymerizing a monomer component containing an epoxy group-containing monomer represented by the formula (a) above and a hydroxyl group-containing monomer represented by the formula (b1) above, and a step (2) of reacting the polymer obtained in the polymerization step (1) with an acid group-containing compound represented by the formula (b2) or (b3) above. By producing the copolymer in this manner, gelation can be suppressed during the production of the copolymer, and the copolymer having the structural unit (A) and the structural unit (B) can be efficiently obtained. That is, the present invention also includes a step (1) of polymerizing a monomer component containing an epoxy group-containing monomer represented by formula (a) and a hydroxyl group-containing monomer represented by formula (b1), a polymer obtained in the above polymerization step (1), and a step (2) of reacting the polymer with an acid group-containing compound represented by the above formula (b2) or formula (b3). The manufacturing method of the copolymer is characterized by including these steps.

[0133] Each step in the above manufacturing method will be described. Step (1) In the method for producing the copolymer of the present invention, a monomer component containing an epoxy group-containing monomer represented by the above formula (a) and a hydroxyl group-containing monomer represented by the above formula (b1) is polymerized. Examples of the epoxy group-containing monomer represented by the above formula (a) include the monomers described as monomers capable of introducing the structural unit (A) of the copolymer described above. Examples of the hydroxyl group-containing monomer represented by the above formula (b1) include those described above.

[0134] The content ratio of the epoxy group-containing monomer and the hydroxyl group-containing monomer is not particularly limited, and may be appropriately set so that the content ratio of the structural unit (A) and the structural unit (B) described above is obtained in the resulting copolymer.

[0135] The monomer component may contain other monomer components other than the acid group-containing compound used in step (2) described later. Examples of the other monomer components include the monomer components described above.

[0136] The method for polymerizing the monomer component is not particularly limited, and polymerization may be carried out by the known methods described above. The polymerization temperature and time are as described above.

[0137] Also, the above polymerization may use commonly used polymerization initiators, chain transfer agents, catalysts, solvents, etc.

[0138] Step (2) Next, the method includes a step of reacting the polymer obtained in the above step (1) with an acid group-containing compound represented by the above formula (b2) or formula (b3). By reacting the polymer (base polymer) obtained in the step (1) with the acid group-containing compound represented by the formula (b2) or (b3), the acid group-containing compound is added to the hydroxyl groups of the polymer (base polymer) obtained in the step (1), thereby forming long-chain acid groups.

[0139] The reaction method is not particularly limited, and can be carried out by a known method. The reaction temperature is, for example, preferably 25 to 100°C, more preferably 30 to 90°C. The reaction time is not particularly limited, but may be, for example, 1 to 20 hours.

[0140] The step of reacting the acid group-containing compound may be carried out in the presence of a basic compound. By carrying out the reaction in the presence of a basic compound, the reaction between the hydroxyl group and the acid group can be carried out at a lower temperature of 70°C or less. Furthermore, since the reaction is carried out under such low temperature conditions, the reaction between the epoxy group and the acid group can be suppressed, and only the reaction between the hydroxyl group and the acid group can proceed, allowing the copolymer having the structural unit (A) and the structural unit (B) to be produced more efficiently.

[0141] For example, in step (2), the polymer (base polymer) obtained in step (1) may be reacted with the acid group-containing compound in the presence of a basic compound at 70° C. or lower. In this case, if the temperature exceeds 70° C., the reaction between the epoxy group and the acid group may proceed more easily, which may cause the resin to gel.

[0142] Examples of the acid group-containing compound represented by the formula (b2) or (b3) include the acid group-containing compounds described above. Examples of the basic compound include ammonia; primary amines such as methylamine; secondary amines such as dimethylamine; tertiary amines such as triethylamine and diethylmethylamine; aliphatic amines such as dimethylethanolamine, n-butylamine, and diethylamine; cycloaliphatic amines such as cyclohexylamine; heterocyclic amines such as piperidine, morpholine, N-ethylpiperidine, N-ethylmorpholine, and pyridine; aromatic amines such as benzylamine, N-methylaniline, and N,N-dimethylaniline; tetraalkylammonium halides such as tetramethylammonium chloride and tetraethylammonium chloride; tetraalkylammonium organic acid salts such as tetramethylammonium acetate; tetraalkylammonium inorganic acid salts such as tetramethylammonium hydrogen sulfate and tetraethylammonium hydrogen sulfate; (hydroxy)alkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and mono-hydroxyethyltrimethylammonium hydroxide; hydroxides of alkali metals such as sodium and potassium; hydroxides of transition metals such as barium, strontium, calcium, and lanthanum; free salts of complex salts such as [Pt(NH3)6](OH)4; phosphorus compounds such as triphenylphosphine, tricyclohexylphosphine, and trimethylphosphine. Among them, from the viewpoints of ease of evaporation and ease of handling, secondary amines, tertiary amines, heterocyclic amines, and phosphorus compounds are preferred. From the viewpoint of suppressing side reactions and suppressing an increase in the molecular weight of the polymer after addition, tertiary amines and triphenylphosphine are more preferred.

[0143] The amount of the basic compound used is not particularly limited, but from the viewpoint of reaction efficiency, it is preferably 0 to 5 mol%, more preferably 0 to 4 mol%, and still more preferably 0 to 3 mol% based on 100 mol% of the amount of the acid group-containing compound used.

[0144] The amount of the acid group-containing compound used may be appropriately set according to the purpose and use of the copolymer to be obtained, so that the content ratio of the structural unit (B) falls within a desired range, or so that the acid value of the copolymer falls within a desired range.

[0145] The concentration of the total monomer components in the total amount of the polymerization solution during the addition reaction of the acid group-containing compound is preferably 40% by mass or more, and more preferably 50% by mass or more. When the concentration of the total monomer components is within the above range, the acid group-containing compound can be added to the base polymer without using the basic compound as a catalyst, and the storage stability of the resulting copolymer can be improved. Thus, when the monomer concentration relative to the total amount of the polymerization solution of the copolymer is high, the acid group-containing compound can be added without a catalyst, and the storage stability of the copolymer can be improved.

[0146] In the above reaction, commonly used catalysts, solvents, etc. may be used.

[0147] In addition, to produce a copolymer having a polymerizable double bond in the side chain, after the above step (1), an acid group-containing monomer or an isocyanate group-containing polymerizable monomer may be added to the hydroxyl group, or after the above step (1) or (2), an acid group-containing monomer may be added to the epoxy group, whereby a polymerizable double bond can be introduced into the side chain of the copolymer. Examples of the acid group-containing monomer include those described above, and preferably (meth)acrylic acid. Examples of the isocyanate group-containing polymerizable monomer include the unsaturated isocyanates described above, and preferably isocyanatoethyl (meth)acrylate in that it can undergo an addition reaction at low temperature and the storage stability of the copolymer can be good. The above addition reaction is not particularly limited and can be carried out by a known method. In the above addition reaction, commonly used compounds, catalysts, solvents, etc. may be used.

[0148] Among them, as the catalyst, the basic compounds described above are preferably mentioned, and secondary amines, tertiary amines, heterocyclic amines, and phosphorus compounds are preferred, and tertiary amines and triphenylphosphine are more preferred. Further, tin compounds such as dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin acetate, dioctyltin oxide, tributyltin chloride, etc., which are generally used as reaction catalysts for isocyanate monomers and hydroxyl groups, can also be preferably used.

[0149] The method for producing the copolymer may include other steps other than the reaction steps described above. For example, an aging step, a neutralization step, a step for deactivating a polymerization initiator and a chain transfer agent, a dilution step, a drying step, a concentration step, a purification step, etc. can be mentioned. These steps can be carried out by known methods.

[0150] 2. Copolymer solution The present invention is also a copolymer solution characterized by containing the above-mentioned copolymer and a protic polar solvent. The copolymer solution of the present invention has excellent storage stability. As described above, the above copolymer has an acid group and an epoxy group, and since these groups have high reactivity, the curing of the above copolymer at low temperature is facilitated, while it has been difficult to ensure storage stability. The present inventor has found that by adding a protic polar solvent, the storage stability of the above copolymer can be improved, and high solvent resistance and storage stability can be achieved at the same time. The reason why the addition of the protic polar solvent improves the storage stability of the above copolymer is not clear, but in the above copolymer, an acid group such as a carboxyl group exists at a position separated from the main chain, so that the protic polar solvent can form a hydrogen bond with the above acid group relatively easily, the anionic property of the acid group is reduced, and the reactivity between the acid group and the epoxy group is suppressed.

[0151] <Protic polar solvent> Examples of the protic polar solvent include water, alcohol solvents, amine solvents, and phenol solvents. Among these, the protic polar solvent is preferably an alcohol solvent.

[0152] As the alcohol solvent, saturated alcohols are preferably mentioned, and examples include monohydric alcohols (monoalcohols), polyhydric alcohols, glycol monoethers, and the like. Specific examples of the alcohol solvent include primary alcohols such as methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol monophenyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol mono-n-butyl ether, tripropylene glycol, and tripropylene glycol mono-n-butyl ether; secondary alcohols such as isopropanol, 2-butanol, 2-pentanol, 3-pentanol, 2-hexanol, cyclohexanol, 2-heptanol, 3-heptanol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, propylene glycol monophenyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, or tripropylene glycol monomethyl ether; Examples of the tertiary alcohol include tert-butanol, tert-pentanol, tert-hexanol, and the like. Among them, the alcohol-based solvent is preferably a secondary alcohol or a tertiary alcohol in terms of suppressing the reactivity with the epoxy group and reducing the viscosity of the copolymer solution.

[0153] The number of carbon atoms of the alcohol-based solvent is preferably 1 to 10, more preferably 2 to 8, and still more preferably 3 to 6 in terms of having a relatively low boiling point and being easily removed by heating.

[0154] As the alcohol-based solvent, propylene glycol monomethyl ether is particularly preferred.

[0155] Examples of the amine-based solvent include diethyleneamine, dimethylamine, oleylamine, and the like.

[0156] Examples of the phenol-based solvent include phenol, cresol, o-cresol, m-cresol, p-cresol, xylenol, and the like.

[0157] The above-mentioned protic polar solvent may be used alone or in combination of two or more.

[0158] The boiling point of the above-mentioned protic polar solvent is preferably 70 to 170 °C, more preferably 100 to 160 °C, and still more preferably 120 to 150 °C in terms of being easily removed by heating, having a certain boiling point, and being likely to form a flat film.

[0159] The content of the protic polar solvent in the copolymer solution is preferably 10% by mass or more, more preferably 30% by mass, and still more preferably 40% by mass or more, based on 100% by mass of the copolymer solid content. Also, in terms of facilitating the concentration adjustment in the curable resin composition, the content of the protic polar solvent is preferably 1000% by mass or less, more preferably 300% by mass or less, and still more preferably 200% by mass or less, based on 100% by mass of the copolymer solid content.

[0160] From the viewpoint of stability, it is preferable that the copolymer solution further contains another solvent capable of forming hydrogen bonds in addition to the protic polar solvent. Examples of the other solvent include N,N-dimethylformamide and the like. Also, as the solvent for concentration adjustment, for example, ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; chloroform; dimethyl sulfoxide; etc. may be included.

[0161] When the copolymer solution contains another solvent other than the protic polar solvent, the content of the protic polar solvent is preferably 5 parts by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, preferably 99% by mass or less, more preferably 90% by mass or less, and still more preferably 80% by mass or less, based on 100% by mass of the total amount of the protic polar solvent and the other solvent.

[0162] The copolymer solution may be prepared by mixing the copolymer purified from a polymerization solution containing the copolymer obtained during polymerization with the protic polar solvent, or by adding the protic polar solvent to a polymerization solution containing the copolymer. When the copolymer solution is prepared by adding the protic polar solvent to a polymerization solution containing the copolymer, the copolymer solution may contain the polymerization solvent.

[0163] The copolymer solution may further contain other components. Examples of the other components include a component that improves the storage stability of the copolymer and a component that improves the curability. Examples of the component that improves the storage stability of the copolymer include acid compounds and phosphoric acid derivatives. Examples of the component that improves the curability of the copolymer include basic compounds. These components may be used appropriately depending on the purpose, and may be used in combination.

[0164] <Acid compounds> The copolymer solution may further contain an acid compound having a pKa of 4.2 or less. By including an acid compound having a pKa of 4.2 or less in the copolymer solution, the reaction between the acid groups and epoxy groups in the copolymer is suppressed, further improving the storage stability of the copolymer. The reason why the storage stability of the copolymer can be improved by including an acid compound having a pKa of 4.2 or less is thought to be that the presence of an acid compound with a stronger acid strength than the acid groups that can form the acid group-containing structural unit (B) in the copolymer reduces the anionic nature of the acid groups in the copolymer, thereby suppressing the reactivity of the acid groups with the epoxy groups. Furthermore, when a basic compound is present in the copolymer solution, the acid compound having a pKa of 4.2 or less captures the basic compound that formed a salt with the carboxyl groups, thereby reducing the nucleophilicity of the carboxyl groups in the copolymer and suppressing the reactivity of the acid groups with the epoxy groups.

[0165] The reason for setting the pKa to 4.2 or less is that the pKa values of the monomers and acid group-containing monomers into which the structural unit (B) can be introduced are set as the threshold. Examples of the pKa values of the monomers include acrylic acid (pKa 4.35), methacrylic acid (pKa 4.26), mono(2-acryloyloxyethyl) succinate (pKa 4.35), and mono(2-methacryloyloxyethyl) succinate (pKa 4.35). The pKa of the acid compound is preferably 3 or less, more preferably 2 or less. The lower limit of the pKa of the acid compound is not particularly limited, but is preferably −3 or more, more preferably 0 or more.

[0166] pKa (acid dissociation constant) refers to the negative common logarithm (reciprocal logarithm) of the equilibrium constant Ka in the dissociation reaction in which hydrogen ions are released from an acid, and specifically refers to the value in water at 25°C. For pKa values, reference can be made to literature such as Chemistry Handbook, Basics II (5th revised edition, Maruzen Co., Ltd.), and values not listed in the literature can be calculated by the method described in the literature.

[0167] Specific examples of acid compounds having a pKa of 4.2 or less include hydrochloric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, polyphosphoric acid, sulfuric acid, sulfurous acid, thiosulfuric acid, dimethyl sulfite, diethyl sulfite, dipropyl sulfite, dibutyl sulfite, diphenyl sulfite, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, diphenyl sulfate, aromatic sulfonic acids such as benzenesulfinic acid, toluenesulfinic acid, naphthalenesulfinic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, diisopropylnaphthalenesulfonic acid, and diisobutylnaphthalenesulfonic acid; alkylsulfonic acids such as methylsulfonic acid, ethylsulfonic acid, and propylsulfonic acid; α-olefinsulfonic acids; sulfonated polystyrenes; methyl acrylate-sulfonated styrene copolymers; and derivatives thereof.

[0168] The molecular weight of the acid compound is preferably 400 or less, more preferably 350 or less. The molecular weight of the acid compound is preferably 150 or more, more preferably 250 or more.

[0169] <Phosphate derivatives> The copolymer solution may further contain a phosphoric acid derivative, which can improve the storage stability of the copolymer.

[0170] Preferred examples of the phosphoric acid derivative include phosphate ester, phosphite ester, phosphorous acid, hypophosphorous acid, phosphonic acid, and phosphinic acid, and more preferred examples include phosphate ester, phosphonic acid, and phosphinic acid. Examples of the ester group of the phosphate ester or phosphite ester include alkyl ester groups, aryl ester groups, aralkyl ester groups, and ester groups having a polymerizable double bond. Examples of the alkyl of the alkyl ester group include methyl, ethyl, octyl, and 2-ethylhexyl. Examples of the aryl of the aryl ester group include phenyl, tolyl, and naphthyl. Examples of the aralkyl of the aralkyl ester group include benzyl. Examples of the ester group having a polymerizable double bond include a 2-acryloyloxyethyl ester group and a 2-methacryloyloxyethyl ester group.

[0171] Specific examples of the above phosphate esters include, for example, monoalkyl phosphates such as methyl phosphate; dialkyl phosphates such as dibutyl phosphate; trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tridecyl phosphate, trioctadecyl phosphate, distearyl pentaerythrityl diphosphate, tris(2-chloroethyl) phosphate, tris(2,3-dichloropropyl) phosphate; tricycloalkyl phosphates such as tricyclohexyl phosphate; monoaryl phosphates; diaryl phosphates; triaryl phosphates such as triphenyl phosphate, tricresyl phosphate, tris(nonylphenyl) phosphate, 2-ethylphenyldiphenyl phosphate; phosphate esters containing an ester group having a polymerizable double bond such as 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, 3-methacryloyloxypropyl acid phosphate, methacryloyloxypolyoxyethylene glycol acid phosphate, methacryloyloxypolyoxypropylene glycol acid phosphate. Specific examples of the above phosphonic acids include alkylphosphonic acids such as methylphosphonic acid, and arylphosphonic acids such as phenylphosphonic acid. Specific examples of the above phosphinic acids include alkylphosphinic acids such as methylphosphinic acid, and arylphosphinic acids such as phenylphosphinic acid.

[0172] Among them, as the above phosphate ester, a phosphate ester containing an ester group having a polymerizable double bond is preferable. When a phosphate ester containing an ester group having a polymerizable double bond is used, a crosslinked structure is formed together with the above copolymer and polymerizable compound during the curing of the curable resin composition containing the above copolymer solution, and volatilization and elution of the contained components are suppressed, and problems such as contamination of the reaction system and deterioration of electrical insulation can be significantly suppressed. The above phosphate ester preferably contains two or more polymerizable double bonds.

[0173] In the present invention, commercially available products can be used as the phosphate ester containing an ester group having the above polymerizable double bond. For example, Ryoto Ester P-1M, Ryoto Ester P-2M (both manufactured by Kyoeisha Chemical Co., Ltd.), Hosmer M (manufactured by Uni-Chemical Co., Ltd.), etc. can be used. Among them, Ryoto Ester P-2M is preferable.

[0174] The molecular weight of the above phosphate derivative is preferably 400 or less, and more preferably 350 or less. When the molecular weight of the above phosphate derivative is 400 or less, the resin solid content at the time of addition can be lowered, and the storage stability is further improved. In addition, the effects of improving the anionic property of the acid group and reducing the nucleophilic force become greater. The molecular weight of the above phosphate derivative is preferably 150 or more, and more preferably 250 or more. When the molecular weight of the above phosphate derivative is 150 or more, the compatibility with the resin composition can be further improved.

[0175] The above phosphate derivative may be an acid compound having a pKa of 4.2 or less as described above. That is, from the viewpoints of storage stability and compatibility, the copolymer solution of the present invention preferably contains an acid compound or a phosphate derivative having a pKa of 4.2 or less, and more preferably contains a phosphate derivative having a pKa of 4.2 or less.

[0176] The contents of the above acid compound and phosphate derivative are not particularly limited and may be appropriately set according to the use, the blending of other components, etc. Preferably, based on 100% by mass of the total solid content of the copolymer solution, usually 0.01 to 5% by mass is preferable, 0.01 to 3% by mass is more preferable, and 0.02 to 2% by mass is still more preferable. In addition, the above content is the total amount of the above acid compound and phosphate derivative when the above acid compound and phosphate derivative are used in combination. Further, in this specification, the "total solid content" means the total amount of components that form a cured product (excluding solvents and the like that volatilize during the formation of the cured product).

[0177] The content of the above acid compound and phosphate derivative is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and still more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the copolymer in the copolymer solution. In addition, when the above acid compound and phosphate derivative are used in combination, the above content is the total amount of the above acid compound and phosphate derivative.

[0178] When the above copolymer solution further contains a basic compound described later, the content of the above acid compound and phosphate derivative is preferably 50 to 200 mol%, more preferably 70 to 150 mol%, and still more preferably 80 to 120 mol% with respect to 100 mol% of the amount of the basic compound used. By setting the content of the above acid compound and phosphate derivative in the range of 0.5 to 2.0 molar equivalents with respect to the basic compound, the storage stability of the above copolymer can be further improved, and the coloring of the cured product can be further suppressed. In addition, when the above acid compound and phosphate derivative are used in combination, the above content is the total amount of the above acid compound and phosphate derivative.

[0179] <Basic compound> The above copolymer solution may further contain a basic compound. By containing a basic compound, the crosslinking reaction can proceed well even under low-temperature curing conditions of 160°C or lower during the curing of the copolymer, and a cured product with further excellent solvent resistance can be obtained.

[0180] Examples of the above basic compound include the basic compounds described above. Among them, amine compounds are preferred. In addition, as the above basic compound, secondary amines, tertiary amines, heterocyclic amines, and phosphorus compounds are more preferred in terms of ease of evaporation and ease of handling, and tertiary amines and triphenylphosphine are more preferred in terms of suppressing side reactions and suppressing the increase in the molecular weight of the polymer after addition.

[0181] The content of the basic compound is not particularly limited and may be appropriately set depending on the application and the blending of other components, but is preferably 0.01 to 10 mass %, more preferably 0.01 to 6 mass %, and even more preferably 0.02 to 4 mass %, relative to 100 mass % of the total solid content of the copolymer solution.

[0182] The content of the basic compound is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 6 parts by mass, relative to 100 parts by mass of the copolymer.

[0183] In addition, if the basic compound used as a catalyst during the synthesis of the above-mentioned copolymer (during the addition reaction) remains in the copolymer solution after the synthesis of the copolymer, the content in the copolymer solution can be adjusted by adding the basic compound according to the remaining amount.

[0184] <Method of producing copolymer solution> A preferred example of a method for producing the copolymer solution includes a step (polymerization step) of polymerizing monomer components including an epoxy group-containing monomer represented by formula (a) above and a hydroxyl group-containing monomer represented by formula (b1) above, a step (reaction step) of reacting the polymer obtained in the polymerization step with an acid group-containing compound represented by formula (b2) or (b3) above in the presence of a basic compound, and a step (addition step) of adding an acid compound having a pKa of 4.2 or less and a protic polar solvent. That is, the present invention also includes a method for producing a copolymer solution, which comprises the steps of: polymerizing a monomer component containing an epoxy group-containing monomer represented by formula (a) and a hydroxyl group-containing monomer represented by formula (b1); reacting the polymer obtained in the polymerization step with an acid group-containing compound represented by formula (b2) or formula (b3) in the presence of a basic compound; and adding an acid compound having a pKa of 4.2 or less and a protic polar solvent.

[0185] The polymerization step may be the same as step (1) in the above-mentioned method for producing the copolymer.

[0186] The reaction step may be the same as step (2) in the above-mentioned copolymer production method, in which the step (2) is carried out in the presence of a basic compound. Specific examples of the acid group-containing compound represented by formula (b2) or formula (b3) and the basic compound include the same as the acid group-containing compound and the basic compound described above.

[0187] The acid compound having a pKa of 4.2 or less and the protic polar solvent used in the above-mentioned addition step are as described above.

[0188] 3.Curable resin composition The copolymer of the present invention and the copolymer solution can be combined with other components to form a curable resin composition. Since the curable resin composition contains the copolymer of the present invention, it can provide a cured product with excellent solvent resistance even under low-temperature curing conditions. Furthermore, when the curable resin composition contains the copolymer solution, it also has excellent storage stability. Such a curable resin composition containing the copolymer or copolymer solution is also one of the preferred embodiments of the present invention.

[0189] In the curable resin composition, the content of the copolymer is not particularly limited and may be set appropriately depending on the application, the blending of other components, etc. For example, relative to 100% by mass of the total solid content of the curable resin composition, the content is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less. In this specification, the term "total amount of solids" refers to the total amount of components that form the cured product (excluding solvents and the like that volatilize during the formation of the cured product).

[0190] The curable resin composition preferably contains the above-mentioned protic polar solvent, in that the stability of the composition is improved. In order to ensure the stability of the curable resin composition, the content of the protic polar solvent in the curable resin composition is preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, relative to 100% by mass of the solid content of the copolymer, and is preferably 3000% by mass or less, and more preferably 1000% by mass or less.

[0191] In order to ensure the stability of the curable resin composition, the content of the protic polar solvent in the curable resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, relative to 100% by mass of the solid content of the curable resin composition, and is preferably 400% by mass or less, more preferably 300% by mass or less, and even more preferably 200% by mass or less.

[0192] The curable resin composition may further contain various components such as a polymerizable compound, a polymerization initiator, etc. Examples of the various components such as the polymerizable compound and the polymerization initiator include the same components as those of the photosensitive resin composition described below. As an example of a preferred embodiment of the curable resin composition, a photosensitive resin composition will be described.

[0193] 3-1. Photosensitive resin composition The copolymer or copolymer solution of the present invention can be further combined with a polymerizable compound and a photopolymerization initiator to form a photosensitive resin composition. The photosensitive resin composition contains the copolymer described above, and therefore can provide a cured product with excellent solvent resistance even under low-temperature curing conditions of 160°C or less, for example, about 90°C. Furthermore, since it further contains a polymerizable compound, it can provide a cured product with excellent physical properties such as curability, adhesion to substrates, surface hardness, and heat resistance. Such a photosensitive resin composition containing the copolymer or copolymer solution described above, a polymerizable compound, and a photopolymerization initiator also constitutes one aspect of the present invention.

[0194] In the photosensitive resin composition of the present invention, the content of the above copolymer is not particularly limited and may be appropriately set according to the use, the blending of other components, etc. For example, it is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less, based on 100% by mass of the total solid content of the photosensitive resin composition.

[0195] <Polymerizable compound> The above polymerizable compound is a low molecular compound having a polymerizable unsaturated bond (also referred to as a polymerizable unsaturated group) that can be polymerized by irradiation with active energy rays such as free radicals, electromagnetic waves (e.g., infrared rays, ultraviolet rays, X-rays, etc.), electron beams, etc. Examples include monofunctional compounds having one polymerizable unsaturated group in the molecule and polyfunctional compounds having two or more.

[0196] Examples of the above monofunctional compounds include N-substituted maleimide monomers; (meth)acrylic acid esters; (meth)acrylamides; unsaturated monocarboxylic acids; unsaturated polyvalent carboxylic acids; unsaturated monocarboxylic acids in which the chain between the unsaturated group and the carboxyl group is extended; unsaturated acid anhydrides; aromatic vinyls; conjugated dienes; vinyl esters; vinyl ethers; N-vinyl compounds; unsaturated isocyanates; etc. Examples of these include the same compounds as those listed as the monomer components of the above copolymer. Also, monomers having an active methylene group or an active methine group can be used.

[0197] Examples of the above polyfunctional compounds include the following compounds, etc. Bifunctional (meth)acrylate compounds such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, bisphenol A alkylene oxide di(meth)acrylate, bisphenol F alkylene oxide di(meth)acrylate;

[0198] Trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, ethylene oxide - added trimethylolpropane tri(meth)acrylate, ethylene oxide - added ditrimethylolpropane tetra(meth)acrylate, ethylene oxide - added pentaerythritol tetra(meth)acrylate, ethylene oxide - added dipentaerythritol hexa(meth)acrylate, propylene oxide - added trimethylolpropane tri(meth)acrylate, propylene oxide - added ditrimethylolpropane tetra(meth)acrylate, propylene oxide - added pentaerythritol tetra(meth)acrylate, propylene oxide - added dipentaerythritol hexa(meth)acrylate, ε - caprolactone - added trimethylolpropane tri(meth)acrylate, ε - caprolactone - added ditrimethylolpropane tetra(meth)acrylate, ε - caprolactone - added pentaerythritol tetra(meth)acrylate, ε - caprolactone - added dipentaerythritol hexa(meth)acrylate, succinic acid - modified dipentaerythritol pentaacrylate, succinic acid - modified pentaerythritol triacrylate, phthalic acid - modified dipentaerythritol pentaacrylate, phthalic acid - modified pentaerythritol triacrylate, the following formula:

[0199] [Chemical formula]

[0200] A polyfunctional (meth)acrylate compound having three or more functional groups such as a modified product of dipentaerythritol hexaacrylate represented by the formula;

[0201] Polyfunctional vinyl ethers such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether;

[0202] (Meth)acrylic acid 2-vinyloxyethyl, (meth)acrylic acid 3-vinyloxypropyl, (meth)acrylic acid 1-methyl-2-vinyloxyethyl, (meth)acrylic acid 2-vinyloxypropyl, (meth)acrylic acid 4-vinyloxybutyl, (meth)acrylic acid 4-vinyloxycyclohexyl, (meth)acrylic acid 5-vinyloxypentyl, (meth)acrylic acid 6-vinyloxyhexyl, (meth)acrylic acid 4-vinyloxymethylcyclohexylmethyl, (meth)acrylic acid p-vinyloxymethylphenylmethyl, (meth)acrylic acid 2-(vinyloxyethoxy)ethyl, (meth)acrylic acid 2-(vinyloxyethoxyethoxyethoxy)ethyl and other vinyl ether group-containing (meth)acrylic acid esters;

[0203] Polyfunctional allyl ethers such as ethylene glycol diallyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, propylene glycol diallyl ether, butylene glycol diallyl ether, hexanediol diallyl ether, bisphenol A alkylene oxide diallyl ether, bisphenol F alkylene oxide diallyl ether, trimethylolpropane triallyl ether, ditrimethylolpropane tetraallyl ether, glycerin triallyl ether, pentaerythritol tetraallyl ether, dipentaerythritol pentaallyl ether, dipentaerythritol hexaallyl ether, ethylene oxide-added trimethylolpropane triallyl ether, ethylene oxide-added ditrimethylolpropane tetraallyl ether, ethylene oxide-added pentaerythritol tetraallyl ether, ethylene oxide-added dipentaerythritol hexaallyl ether;

[0204] (Meth)acrylic acid esters containing allyl groups such as allyl (meth)acrylate; polyfunctional (meth)acryloyl group-containing isocyanurates such as tris(acryloyloxyethyl) isocyanurate, tris(methacryloyloxyethyl) isocyanurate, alkylene oxide-added tris(acryloyloxyethyl) isocyanurate, alkylene oxide-added tris(methacryloyloxyethyl) isocyanurate; polyfunctional allyl group-containing isocyanurates such as triallyl isocyanurate; polyfunctional urethane (meth)acrylates obtained by reacting polyfunctional isocyanates such as tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate with hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate; polyfunctional aromatic vinyls such as divinylbenzene; etc. These polymerizable compounds may be used alone or in combination of two or more. However, a polymer having a vinyl ether group in the side chain can improve the curability of the resin composition but may reduce the storage stability. Therefore, from the viewpoint of storage stability, it is preferable that the photosensitive resin composition does not contain a polymer having a vinyl ether group in the side chain.

[0205] Among the above polymerizable compounds, from the viewpoint of further enhancing the curability of the photosensitive resin composition, it is preferable to use a polyfunctional polymerizable compound. The number of functional groups of the above polyfunctional polymerizable compound is preferably 3 or more, more preferably 4 or more. Also, the number of functional groups is preferably 10 or less, more preferably 8 or less. The molecular weight of the above polymerizable compound is not particularly limited, but from the viewpoint of handling, for example, it is preferably 2000 or less.

[0206] Among the above polyfunctional polymerizable compounds, from the viewpoints of reactivity, economy, availability, etc., preferably compounds having a (meth)acryloyl group such as polyfunctional (meth)acrylate compounds, polyfunctional urethane (meth)acrylate compounds, (meth)acryloyl group-containing isocyanurate compounds, etc. are mentioned, and more preferably polyfunctional (meth)acrylate compounds are mentioned. By including a compound having a (meth)acryloyl group, the photosensitive resin composition becomes more excellent in photosensitivity and curability, and a cured product with higher hardness and higher transparency can be obtained. As the above polyfunctional polymerizable compound, it is more preferable to use a polyfunctional (meth)acrylate compound having 3 or more functional groups.

[0207] The above polymerizable compound may be used alone or in combination of two or more.

[0208] In the photosensitive resin composition of the present invention, the content of the above polymerizable compound is not particularly limited and may be appropriately set as long as the effects of the present invention are exhibited. However, from the point of making the photosensitive resin composition have an appropriate viscosity, based on 100% by mass of the total solid content of the photosensitive resin composition, it is preferably 5 to 60% by mass, more preferably 10 to 50% by mass.

[0209] <Photoinitiator> As the photoinitiator, preferably a radical-polymerizable photoinitiator is used. A radical-polymerizable photoinitiator generates polymerization-initiating radicals upon irradiation with active energy rays such as electromagnetic waves or electron beams.

[0210] Specific examples of the above photoinitiator include, for example, aminoketone compounds such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (“IRGACURE 907”, manufactured by BASF), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (“IRGACURE 369”, manufactured by BASF), 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (“IRGACURE 379”, manufactured by BASF); benzyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethane-1-one (“IRGACURE 651”, manufactured by BASF), phenylglyoxylic acid methyl ester (“DAROCUR MBF”, manufactured by BASF); hydroketone compounds such as 1-hydroxy-cyclohexyl-phenyl-ketone (“IRGACURE 184”, manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (“DAROCUR 1173”, manufactured by BASF), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (“IRGACURE 2959”, manufactured by BASF), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (“IRGACURE 127”, manufactured by BASF), [1-hydroxy-cyclohexyl-phenyl-ketone + benzophenone] (“IRGACURE 500”, manufactured by BASF); and other alkylphenone compounds exemplified in paragraphs

[0084] to

[0086] of JP-A-2013-227485.1,2-Octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime) ("OXE01", manufactured by BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) ("OXE02", manufactured by BASF), 1,2-Octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone ("OXE03", manufactured by BASF), 1-[9-ethyl Examples of suitable oxime ester compounds include oxime ester compounds such as [-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime) ("OXE04", manufactured by BASF); benzophenone compounds; benzoin compounds; thioxanthone compounds; halomethylated triazine compounds; halomethylated oxadiazole compounds; biimidazole compounds; titanocene compounds; benzoic acid ester compounds; acridine compounds; and phosphine oxide compounds. Of these, aminoketone compounds and oxime ester compounds are preferred. The photopolymerization initiators may be used alone or in combination of two or more.

[0211] The content of the photopolymerization initiator is not particularly limited as long as it is within a range in which the effects of the present invention are exhibited, and may be set appropriately. For example, the content is preferably 0.3 to 20 mass%, more preferably 0.5 to 10 mass%, and even more preferably 1 to 8 mass%, relative to 100 mass% of the total solid content of the photosensitive resin composition of the present invention.

[0212] <Photoacid generator> The photosensitive resin composition of the present invention preferably further contains a photoacid generator. By further containing a photoacid generator, the curability of the photosensitive resin composition can be further improved. The above photoacid generator is a compound that generates an acid when exposed to active energy rays such as radiation. Examples include strong acids such as toluenesulfonic acid or boron tetrafluoride, onium salts such as sulfonium salts, ammonium salts, phosphonium salts, iodonium salts, or selenium salts; iron-allyl complexes; silanol-metal chelate complexes; sulfonic acid derivatives such as disulfones, disulfonyldiazomethanes, disulfonylmethanes, sulfonylbenzoylmethanes, imidosulfonates, or benzoin sulfonates; organic halogen compounds; and the like.

[0213] The content of the above photoacid generator is preferably 0.3 to 20% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 8% by mass with respect to 100% by mass of the total solid content of the photosensitive resin composition.

[0214] <Other Components> In addition to the above-described components, the photosensitive resin composition of the present invention may contain other components as necessary. Examples of the above other components include solvents; colorants (pigments, dyes); dispersants; heat resistance improvers; leveling agents; development aids; inorganic fine particles such as silica fine particles; coupling agents such as silane-based, aluminum-based, or titanium-based coupling agents; fillers, thermosetting resins such as epoxy resins, phenolic resins, or polyvinylphenol; curing aids such as polyfunctional thiol compounds; plasticizers; polymerization inhibitors; ultraviolet absorbers; antioxidants; matting agents; antifoaming agents; antistatic agents; slip agents; surface modifiers; thixotropic agents; thixotropic aids; quinonediazide compounds; polyhydric phenol compounds; cationic polymerizable compounds; acid generators; and the like. These may be used alone or in combination of two or more. These other components may be appropriately selected from known ones for use, and their usage amounts can also be appropriately set. For example, when the above photosensitive resin composition is used for color filter applications, the photosensitive resin composition preferably contains a colorant.

[0215] <Preparation of Photosensitive Resin Composition> As a method for preparing the photosensitive resin composition of the present invention, there is no particular limitation, and known methods may be used. For example, a method of mixing and dispersing the above-described respective components using various mixers and dispersers can be mentioned. The mixing and dispersing step is not particularly limited and may be carried out by known methods. Further, it may further include other commonly performed steps. When the above photosensitive resin composition contains a colorant, it is preferably prepared through known steps such as a dispersion treatment step of the colorant.

[0216] <Cured product> The cured product obtained by curing the copolymer, copolymer solution, or photosensitive resin composition (curable resin composition) of the present invention has excellent solvent resistance. Such a copolymer, copolymer solution, or cured product of the photosensitive resin composition is also one of the present inventions.

[0217] When the above cured product is a cured film, its film thickness is preferably 0.1 μm or more. When the film thickness is 0.1 μm or more, more excellent solvent resistance can be exhibited. The film thickness is more preferably 0.5 μm or more, and still more preferably 1 μm or more. The upper limit value of the film thickness is not particularly limited and may be appropriately set according to the purpose and use of the cured film. For example, it is preferably 20 μm or less, more preferably 15 μm or less, and still more preferably 10 μm or less.

[0218] As a method for obtaining the above cured product, there is no particular limitation, and known methods may be used. For example, a method of applying or molding the above-described copolymer, copolymer solution, or photosensitive resin composition on a substrate and then curing it by drying, heating, irradiation with energy rays such as ultraviolet rays, or a combination thereof to obtain a cured product can be mentioned.

[0219] When the copolymer, copolymer solution, or photosensitive resin composition of the present invention is used, a cured product excellent in solvent resistance can be obtained even under low-temperature curing conditions. As a method for producing such a cured product, for example, a method including a step of applying the above photosensitive resin composition onto a substrate to form a coating film, a step of irradiating the formed coating film with light, and a step of heating the light-irradiated coating film at 160°C or lower is preferably mentioned.

[0220] The above substrate is not particularly limited and may be appropriately selected according to the purpose and application. For example, substrates made of various materials such as glass plates and plastic plates can be mentioned.

[0221] The method for applying the above photosensitive resin composition to form a coating film is not particularly limited and can be carried out by known methods such as spin coating, slit coating, roll coating, and casting coating. In the above production method, after applying the above photosensitive resin composition onto the substrate, it is preferable to dry the coated object to form a coating film. The above drying can be carried out by a known method, specifically, the same method as the drying method described in the "arrangement step" of the "<method for manufacturing a color filter>" described later can be used.

[0222] The above production method includes a step of irradiating the coating film with light after forming the coating film. The method for irradiating the formed coating film with light is not particularly limited and can be carried out by a known method. Specifically, the same method as the method described in the "light irradiation step" of the "<method for manufacturing a color filter>" described later can be used.

[0223] When irradiating the coating film with light, the light irradiation may be performed through a photomask. As the photomask, a mask having a light-shielding portion formed according to a target pattern may be used. When performing light irradiation through a photomask, it is preferable to perform a developing process thereafter. By performing the developing process, a target pattern can be formed on the coating film. The developing method is not particularly limited and can be performed by a known method. Specifically, it can be performed in the same manner as the method described in the "Developing Process" of the "Method for Manufacturing a Color Filter" described later.

[0224] The above manufacturing method also includes a step of heating the light-irradiated coating film at 160 °C or lower. Since the above-described photosensitive resin composition is used in the above manufacturing method, the heating step (post-curing step) after light irradiation can be performed under relatively low temperature conditions such as 160 °C or lower. The heating temperature is preferably 155 °C or lower, more preferably 150 °C or lower. As the lower limit of the heating temperature, it is preferably 70 °C or higher, more preferably 90 °C or higher, in terms of maintaining curability. The above heating method other than temperature is not particularly limited and can be performed by a known method. For example, it can be performed in the same manner as the method described in the "Heating Process" of the "Method for Manufacturing a Color Filter" described later.

[0225] <Use> The copolymer, copolymer solution, and photosensitive resin composition (curable resin composition) containing the same of the present invention can give a cured product having excellent solvent resistance with a sufficient curing reaction even under low-temperature curing conditions of 160 °C or lower, for example, about 90 °C. Therefore, it can be suitably used for applications that need to be sufficiently cured under low-temperature conditions or applications that require solvent resistance.

[0226] The copolymer, copolymer solution, and photosensitive resin composition of the present invention can be preferably used for various optical members such as color filters, black matrices, photo spacers, black column spacers, inks, printing plates, printed wiring boards, semiconductor elements, photoresists, insulating films, films, and organic protective films, and components of electrical and electronic devices such as liquid crystal, organic EL, quantum dot, and micro LED liquid crystal display devices, solid-state imaging devices, and touch panel display devices. Among them, it is preferably used for color filter applications. The photosensitive resin composition of the present invention is preferably used as an optical material and also preferably used as a negative type.

[0227] 3. Color Filter A color filter having a cured product of the above-mentioned photosensitive resin composition on a substrate is also one of the preferred forms of the present invention. In the above color filter, the cured product formed by the above-mentioned photosensitive resin composition is particularly suitable as a segment that requires coloring, such as a black matrix or each pixel of red, green, blue, yellow, etc., but is also suitable as a segment that does not necessarily require coloring, such as a photo spacer, a protective layer, and an alignment control rib.

[0228] Examples of the substrate used for the above color filter include glass substrates such as white plate glass, blue plate glass, alkali-strengthened glass, and silica-coated blue plate glass; sheets, films, or substrates made of thermoplastic resins such as polyester, polycarbonate, polyolefin, polysulfone, and ring-opening polymers of cyclic olefins and their hydrogenated products; sheets, films, or substrates made of thermosetting resins such as epoxy resins and unsaturated polyester resins; metal substrates such as aluminum plates, copper plates, nickel plates, and stainless steel plates; ceramic substrates; semiconductor substrates having a photoelectric conversion element; members composed of various materials such as glass substrates provided with a colorant layer on the surface (for example, color filters for LCDs), etc. Among them, from the viewpoint of heat resistance, glass substrates and sheets, films, or substrates made of heat-resistant resins are preferred. Also, the above substrate is preferably a transparent substrate. Further, the substrate may be subjected to corona discharge treatment, ozone treatment, chemical treatment with a silane coupling agent, etc., as necessary.

[0229] <Method for manufacturing a color filter> To obtain the color filter, for example, for each pixel of one color (i.e., for each pixel of one color), a step of disposing the above-described photosensitive resin composition on the substrate (also referred to as the disposing step), a step of irradiating light on the photosensitive resin composition disposed on the substrate (also referred to as the light irradiation step), a step of developing with a developer (also referred to as the developing step), and a step of heat treatment (also referred to as the heating step) are adopted, and it is preferable to adopt a manufacturing method in which the same method is repeated for each color. Note that the formation order of the pixels of each color is not particularly limited.

[0230] (1) Disposing step (preferably coating step) The above disposing step is preferably performed by coating. Examples of the method of coating the photosensitive resin composition on the substrate include spin coating, slit coating, roll coating, casting coating, etc., and any method can be preferably used. In the above disposing step, it is also preferable to dry the coating film after coating the photosensitive resin composition on the substrate. The drying of the coating film can be performed using, for example, a hot plate, an IR oven, a convection oven, etc. The drying conditions are appropriately selected according to the boiling point of the solvent component contained, the type of the curing component, the film thickness, the performance of the dryer, etc., but usually, it is preferably performed at a temperature of 50 to 160°C for 10 seconds to 300 seconds.

[0231] (2) Light irradiation step Examples of the light source for the actinic ray used in the light irradiation step include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, medium-pressure mercury lamps, low-pressure mercury lamps, carbon arcs, and fluorescent lamps, and laser light sources such as argon ion lasers, YAG lasers, excimer lasers, nitrogen lasers, helium cadmium lasers, and semiconductor lasers. Examples of the exposure system include the proximity system, mirror projection system, and stepper system, with the proximity system being preferred. In the step of irradiating with active energy rays, depending on the application, the active energy rays may be irradiated through a predetermined mask pattern. In this case, the exposed area is cured, and the cured area is made insoluble or hardly soluble in a developer.

[0232] (3)Developing process The development step is a step in which, after the light irradiation step described above, development is performed with a developer to remove unexposed areas and form a pattern. This allows a patterned cured film to be obtained. The development treatment can usually be performed at a development temperature of 10 to 50°C by a method such as immersion development, spray development, brush development, or ultrasonic development.

[0233] The developer used in the developing step is not particularly limited as long as it dissolves the photosensitive resin composition, but an organic solvent or an alkaline aqueous solution is usually used, and a mixture thereof may also be used. When an alkaline aqueous solution is used as the developer, it is preferable to wash with water after development. Examples of organic solvents and alkaline aqueous solutions include those described in JP 2015-157909 A.

[0234] (4)Heating process The heating step is a step (also referred to as a "post-curing step") in which the exposed area (cured area) is further cured by baking after the above-mentioned development step. For example, a light source such as a high-pressure mercury lamp is used, and 0.5 to 5 J / cm is used. 2and a step of post-heating at a temperature of, for example, 60 to 200° C. for 10 seconds to 120 minutes. By carrying out such a post-curing step, it is possible to further increase the hardness and adhesion of the patterned cured film. The heating step is generally carried out at a temperature of about 200 to 260° C., but if the photosensitive resin composition is used, sufficient curing can be achieved at a relatively low temperature of 200° C. or less, preferably 160° C. or less, thereby making it possible to obtain a substrate or a cured product with excellent solvent resistance without impairing the properties retained by the substrate or the cured product.

[0235] In the heating step, the heating temperature is preferably 160° C. or lower, more preferably 155° C. or lower, and even more preferably 150° C. or lower. The heating temperature is preferably 70° C. or higher, more preferably 90° C. or higher, and even more preferably 95° C. or higher.

[0236] The heating time in the heating step is not particularly limited, but is preferably 5 to 60 minutes, for example. The heating method is also not particularly limited, but can be performed using a heating device such as a hot plate, a convection oven, or a high-frequency heater.

[0237] The thickness of the cured film obtained by the heating step (i.e., the cured coating film obtained by thermally curing the photosensitive resin composition) is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 1 to 10 μm.

[0238] 4.Display device A display device including the above-described color filter is also one of the preferred embodiments of the present invention. A member for a display device having a cured product of the above photosensitive resin composition and a display device are also included in preferred embodiments of the present invention. The cured product (cured film) formed by the above photosensitive resin composition is stably excellent in adhesion to a substrate or the like, has high hardness, exhibits high smoothness, and has a high transmittance. Therefore, it is particularly suitable as a transparent member and is also useful as a protective film or an insulating film in various display devices.

[0239] As the above display device, for example, a liquid crystal display device, a solid-state imaging device, a touch panel type display device, etc. are suitable. In addition, when the above cured product (cured film) is used as a member for a display device, the member may be a film-like single-layer or multi-layer member composed of the above cured film, or a member in which another layer is further combined with the above single-layer or multi-layer member, or a member including the above cured film during its formation.

[0240] As described above, the copolymer, copolymer solution, and photosensitive resin composition (curable resin composition) of the present invention can provide a cured product having excellent solvent resistance even under low-temperature curing conditions. The copolymer, copolymer solution, and photosensitive resin composition of the present invention can be suitably used for various optical members and constituent members used in liquid crystal / organic EL / quantum dot / micro LED liquid crystal display devices, solid-state imaging devices, touch panel type display devices, etc., for various applications such as electrical and electronic equipment.

Examples

[0241] Examples are given below to explain the present invention in more detail, but the present invention is not limited to only these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0242] In this example, the measurements of various physical properties and the like were carried out by the following methods. (1) Weight average molecular weight (Mw) Using polystyrene as the standard substance and tetrahydrofuran as the eluent, the weight-average molecular weight was measured by GPC (gel permeation chromatography) method with HLC-8220GPC (manufactured by Tosoh Corporation) and column: TSKgel SuperHZM-M (manufactured by Tosoh Corporation).

[0243] (2) Solids content Approximately 1 g of the copolymer solution was weighed into an aluminum cup, about 3 g of acetone was added and dissolved, and then it was naturally dried at room temperature. Then, using a hot air dryer (product name: PHH-101, manufactured by Espec Corporation), it was dried at 140 °C under vacuum for 1.5 hours, cooled in a desiccator, and the mass was measured. From the mass reduction amount, the solids content (mass%) of the polymer solution was calculated.

[0244] (3) Acid value 3 g of the copolymer solution was accurately weighed, dissolved in a mixed solvent of 90 g of acetone and 10 g of water, and titrated using 0.1 N aqueous KOH solution as the titrant. The titration was carried out using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of solids was determined from the acid value of the solution and the solids content of the solution.

[0245] (4) Epoxy equivalent (g / equivalent) It was determined by dividing the mass (g) of the copolymer solids by the number of moles (mol) of epoxy groups contained in the copolymer.

[0246] (5) Double bond equivalent (g / equivalent) It was determined by dividing the mass (g) of the copolymer solids by the amount of double bonds (mol) of the copolymer.

[0247] (6) Solvent resistance The photosensitive resin composition was spin-coated on a 5 cm square glass substrate, dried at 100 °C for 3 minutes, then exposed using a high-pressure mercury lamp at 200 mJ, and heat-treated (post-cured) at 90 °C or 110 °C for 40 minutes respectively to obtain a cured film with a film thickness of 2 μm. Then, the cured film was immersed in 20 g of 1-methyl-2-pyrrolidone (NMP) at 40 °C for 10 minutes and then taken out. For the immersion liquid (NMP) after taking out the cured film, the absorbance was measured with a spectrophotometer UV3100 (manufactured by Shimadzu Corporation) and evaluated according to the following criteria. The larger the absorbance value, the more colorant eluted into the immersion liquid, indicating that the solvent resistance of the photosensitive resin composition is low. (Evaluation Criteria) ◎: The absorbance value is less than 0.2 〇: The absorbance value is 0.2 or more and less than 0.3 △: The absorbance value is 0.3 or more and less than 0.4 ×: The absorbance value is 0.4 or more ××: Film peeling

[0248] (7) Solvent Resistance (Examples 20 - 23) The photosensitive resin composition was spin-coated on a 5 cm square glass substrate, dried at 90 °C for 2 minutes, then exposed using a high-pressure mercury lamp at 100 mJ, and heat-treated (post-cured) at 90 °C for 30 minutes to obtain a cured film with a film thickness of 2 μm. Then, the cured film was immersed in 20 g of the immersion solvent listed in Table 5 at 30 °C for 5 minutes and then taken out. For the immersion solvent after taking out the cured film, the absorbance was measured with a spectrophotometer UV3100 (manufactured by Shimadzu Corporation).

[0249] (8) Viscosity The viscosity of the copolymer solution was measured at 25 °C using a viscometer (VISCOMETER TV-22, manufactured by Toki Sangyo Co., Ltd.).

[0250] (9) Residual Film Ratio The residual film ratio was calculated by measuring the weight of the film before and after the evaluation of the solvent resistance in (7) above. Specifically, the weight of the film before the solvent resistance evaluation was calculated by taking the tare weight of the glass substrate. Then, the weight of the film after the solvent resistance evaluation was divided by the weight of the film before the evaluation to calculate the residual film ratio.

[0251] (Production Example 1) Preparation of Copolymer Solution A-1 (SAH Adduct Solution of HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a condenser tube, and a dropping tank inlet, 185.3 parts of propylene glycol monomethyl ether acetate were charged. After purging with nitrogen, the mixture was heated to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 30.0 parts of 2-hydroxyethyl methacrylate, 70.0 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 18.0 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tanks over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, 189 parts of dimethyl carbonate, and 29.6 parts of propylene glycol monomethyl ether acetate were charged and reacted at 40 °C for 10 hours to obtain copolymer solution A-1. The various physical properties of the obtained copolymer are shown in Table 1.

[0252] (Production Example 2) Preparation of Copolymer Solution A-2 (SAH Adduct Solution of BzMI-CHMA-HEMA-GMA Copolymer) A reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet was charged with 172.0 parts of propylene glycol monomethyl ether acetate. After purging with nitrogen, the mixture was heated to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 43.6 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butyl peroxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 31.33 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, 29.0 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-2. Various physical properties of the obtained copolymer are shown in Table 1.

[0253] (Production Example 3) Preparation of Copolymer Solution A-3 (Solution of SAH Adduct of BzMI-VT-HEMA-GMA Copolymer) 172.0 parts of propylene glycol monomethyl ether acetate was charged into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube and a dropping tank inlet. After purging with nitrogen, the mixture was heated to 90 °C. On the other hand, as the dropping tank (A), a beaker was charged with 10.0 parts of N-benzylmaleimide, 43.6 parts of vinyltoluene, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation), and the mixture was stirred and mixed. As the dropping tank (B), a beaker was charged with 2.0 parts of n-dodecyl mercaptan and 31.33 parts of propylene glycol monomethyl ether acetate, and the mixture was stirred and mixed. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Thereafter, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, 29.0 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-3. Various physical properties of the obtained copolymer are shown in Table 1.

[0254] (Production Example 4) Preparation of copolymer solution A-4 (solution of SAH adduct of BzMI-2EHA-HEMA-GMA copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 172.0 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 43.6 parts of 2-ethylhexyl acrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 31.33 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, 29.0 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-4. The various physical properties of the obtained copolymer are shown in Table 1.

[0255] (Production Example 5) Preparation of Copolymer Solution A-5 (Solution of SAH Adduct of BzMI-CHMA-HEAA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 85.6 parts of diethylene glycol ethyl methyl ether was charged. After nitrogen substitution, it was heated to raise the temperature to 90 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 46.65 parts of cyclohexyl methacrylate, 26.8 parts of N-hydroxyethylacrylamide, 16.55 parts of glycidyl methacrylate, 49.8 parts of diethylene glycol ethyl methyl ether, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 98.0 parts of diethylene glycol ethyl methyl ether. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 13.0 parts of succinic anhydride and 32.5 parts of diethylene glycol ethyl methyl ether were reacted at 60 °C for 10 hours to obtain copolymer solution A-5. Various physical properties of the obtained copolymer are shown in Table 1.

[0256] (Production Example 6) Preparation of copolymer solution A-6 (SAH adduct solution of BzMI-CHMA-GLMA-GMA copolymer) A reaction vessel equipped with a thermometer, a stirrer, a gas inlet pipe, a cooling pipe, and a dropping tank inlet was charged with 50.1 parts of propylene glycol monomethyl ether acetate and 50.1 parts of diethylene glycol ethyl methyl ether. After nitrogen substitution, the mixture was heated to 90°C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 46.65 parts of cyclohexyl methacrylate, 30.0 parts of glycerin monomethacrylate ("Blemmer GL" manufactured by NOF Corporation), 13.35 parts of glycidyl methacrylate, 24.1 parts of propylene glycol monomethyl ether acetate, 24.1 parts of diethylene glycol ethyl methyl ether, and 2.0 parts of t-butylperoxy-2-ethylhexanoate ("Perbutyl (registered trademark) O" manufactured by NOF Corporation). As dropping tank (B), a mixture of 2.0 parts of n-dodecyl mercaptan, 42.5 parts of propylene glycol monomethyl ether acetate, and 42.5 parts of diethylene glycol ethyl methyl ether was stirred and mixed. After the temperature of the reaction vessel reached 90°C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90°C for 30 minutes after the completion of dropping, the temperature was raised to 115°C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 9.4 parts of succinic anhydride, 12.0 parts of propylene glycol monomethyl ether acetate, and 12.0 parts of diethylene glycol ethyl methyl ether were reacted at 60°C for 10 hours to obtain copolymer solution A-6. The various physical properties of the obtained copolymer are shown in Table 1.

[0257] (Production Example 7) Preparation of Copolymer Solution A-7 (SAH Adduct Solution of BzMI-CHMA-HEMA-GMA-NIPAM Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 30.9 parts of propylene glycol monomethyl ether acetate was charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90 °C. On the other hand, as dropping tank (A), a mixture prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 23.6 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 20.0 parts of N-isopropylacrylamide, 10.0 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation) was prepared. As dropping tank (B), a mixture prepared by stirring and mixing 4.0 parts of n-dodecyl mercaptan and 67.4 parts of propylene glycol monomethyl ether acetate was prepared. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride and 4.7 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-7. Various physical properties of the obtained copolymer are shown in Table 1.

[0258] (Production Example 8) Preparation of Copolymer Solution A-8 (Solution of SAH Adduct of MAA Adduct of BzMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 64.0 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to 90 °C. On the other hand, as dropping tank (A), a mixture prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 19.0 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 41.0 parts of glycidyl methacrylate, 10.0 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation) in a beaker was prepared. As dropping tank (B), a mixture prepared by stirring and mixing 4.0 parts of n-dodecyl mercaptan and 54.82 parts of propylene glycol monomethyl ether acetate was prepared. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 13.5 parts of methacrylic acid, 0.34 part of triphenylphosphine, and 0.17 part of Antage W-400 as a catalyst were reacted at 85 °C for 12 hours. Then, after cooling to room temperature, 13.1 parts of succinic anhydride were reacted at 60 °C for 5 hours to obtain copolymer solution A-8. Various physical properties of the obtained copolymer are shown in Table 1.

[0259] (Production Example 9) Preparation of Copolymer Solution A-9 (Solution of SAH Adduct of Cures MOI Adduct of BzMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 208.7 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 14.3 parts of cyclohexyl methacrylate, 55.0 parts of 2-hydroxyethyl methacrylate, 20.7 parts of glycidyl methacrylate, 10.0 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butyl peroxy-2-ethylhexanoate (Perbutyl® O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 98.00 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 26.2 parts of 2-isocyanatoethyl methacrylate (Karenz MOI® manufactured by Showa Denko K.K.), 0.13 part of triethylamine, and 0.19 part of Antage W-400 were reacted at 90 °C for 4 hours. Then, after cooling to room temperature, 14.7 parts of succinic anhydride and 0.28 part of triethylamine as a catalyst were reacted at 60 °C for 7 hours. Further, 69 parts of propylene glycol monomethyl ether was added and reacted at 60 °C for 1 hour to eliminate the remaining succinic anhydride, and copolymer solution A-9 was obtained. The various physical properties of the obtained copolymer are shown in Table 1.

[0260] (Production Example 10) Preparation of Copolymer Solution A-10 (SAH Adduct Solution of AMA-TBMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 172 parts of propylene glycol monomethyl ether acetate were charged. After purging with nitrogen, the mixture was heated to raise the temperature to 90 °C. On the other hand, as dropping tank (A), a mixture prepared by stirring and mixing 10.0 parts of methyl α-(allyloxymethyl)acrylate, 43.6 parts of tert-butyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 30.0 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butyl peroxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation) in a beaker was prepared. As dropping tank (B), a mixture prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 31.3 parts of propylene glycol monomethyl ether acetate was prepared. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining the temperature at 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, and 29.04 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-10. Various physical properties of the obtained copolymer are shown in Table 1.

[0261] (Production Example 11) Preparation of copolymer solution A-11 (solution of SAH adduct of AA adduct of MD-CHMA-HEMA-GMA copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 86.5 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90°C. On the other hand, as dropping tank (A), a mixture prepared by stirring and mixing 10.0 parts of dimethyl-2,2’-[oxybis(methylene)]bis-2-propenoate, 43.6 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 48.8 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation) was prepared. As dropping tank (B), a mixture prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 98 parts of propylene glycol monomethyl ether acetate was prepared. After the temperature of the reaction vessel reached 90°C, while maintaining the same temperature, dropping was started from the dropping tank over 3 hours to carry out polymerization. After maintaining 90°C for 30 minutes after the completion of dropping, the temperature was raised to 115°C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 5.0 parts of acrylic acid, 0.32 part of triethylamine as a catalyst, 0.16 part of Antage W-400, and 20 parts of propylene glycol monomethyl ether acetate were reacted at 115°C for 7 hours. Then, after cooling to room temperature, 12.6 parts of succinic anhydride and 20 parts of propylene glycol monomethyl ether acetate were reacted at 60°C for 10 hours to obtain copolymer solution A-11. The various physical properties of the obtained copolymer are shown in Table 1.

[0262] (Production Example 12) Preparation of Copolymer Solution A-12 (SAH Adduct Solution of CHMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 172 parts of propylene glycol monomethyl ether acetate were charged. After purging with nitrogen, the mixture was heated to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-cyclohexylmaleimide, 43.6 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 16.4 parts of glycidyl methacrylate, 30.0 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butyl peroxy-2-ethylhexanoate (Perbutyl® O manufactured by NOF Corporation). As dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 31.3 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, and 29.0 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-12. The various physical properties of the obtained copolymer are shown in Table 1.

[0263] (Production Example 13) Preparation of Copolymer Solution A-13 (SAH Adduct Solution of BzMI-DCPMA-HEMA-GMA Copolymer) A reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet was charged with 53.4 parts of propylene glycol monomethyl ether acetate. After purging with nitrogen, it was heated to raise the temperature to 90°C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 5.0 parts of N-benzylmaleimide, 25.0 parts of dicyclopentanyl methacrylate, 40.0 parts of 2-hydroxyethyl methacrylate, 30.0 parts of glycidyl methacrylate, 10 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 6.0 parts of n-dodecyl mercaptan and 54.0 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90°C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90°C for 30 minutes after the completion of dropping, the temperature was raised to 115°C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 23.1 parts of succinic anhydride and 9.13 parts of propylene glycol monomethyl ether acetate were reacted at 60°C for 12 hours, and then diluted with 172 parts of propylene glycol monomethyl ether. Copolymer solution A-13 was obtained. Various physical properties of the obtained copolymer are shown in Table 1.

[0264] (Production Example 14) Preparation of Copolymer Solution A-14 (SAH Adduct Solution of BzMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 165.3 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to 90 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 27.5 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 32.5 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 38.0 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, 29.0 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours, and then diluted with 76 parts of propylene glycol monomethyl ether. Copolymer solution A-14 was obtained. Various physical properties of the obtained copolymer are shown in Table 1.

[0265] (Production Example 15) Preparation of Copolymer Solution A-15 (SAH Adduct Solution of BzMI-2EHA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 172.0 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 29.0 parts of 2-ethylhexyl acrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 31.0 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 31.33 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 6.2 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, 16.5 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours, and then diluted with 40 parts of propylene glycol monomethyl ether to obtain copolymer solution A-15. Various physical properties of the obtained copolymer are shown in Table 1.

[0266] (Production Example 16) Preparation of Copolymer Solution A-16 (SAH Adduct Solution of BzMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 83.6 parts of propylene glycol monomethyl ether acetate was charged. After nitrogen substitution, it was heated to raise the temperature to 90 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 20.0 parts of N-benzylmaleimide, 25.0 parts of cyclohexyl methacrylate, 50.0 parts of 2-hydroxyethyl methacrylate, 5.0 parts of glycidyl methacrylate, 50 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 0.3 part of n-dodecyl mercaptan and 99.70 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 34.6 parts of succinic anhydride, 0.40 part of triethylamine as a catalyst, 78.9 parts of propylene glycol monomethyl ether acetate were reacted at 60 °C for 10 hours to obtain copolymer solution A-16. The various physical properties of the obtained copolymer are shown in Table 1.

[0267] (Production Example 17) Preparation of Copolymer Solution A-17 (Solution of SAH Adduct of AA Adduct of BzMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 16.6 parts of propylene glycol monomethyl ether acetate was charged. After purging with nitrogen, the mixture was heated to raise the temperature to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 30.0 parts of N-benzylmaleimide, 10.0 parts of cyclohexyl methacrylate, 10.0 parts of 2-hydroxyethyl methacrylate, 50.0 parts of glycidyl methacrylate, 30.0 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As dropping tank (B), a beaker was prepared by stirring and mixing 6.0 parts of n-dodecyl mercaptan and 82.24 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 22.8 parts of acrylic acid, 0.37 part of triphenylphosphine and 0.18 part of Antage W-400 as a catalyst were reacted at 85 °C for 12 hours. Then, after cooling to room temperature, 4.6 parts of succinic anhydride was reacted at 60 °C for 8 hours, and then diluted with 118 parts of propylene glycol monomethyl ether to obtain copolymer solution A-17. Various physical properties of the obtained copolymer are shown in Table 1.

[0268] (Production Example 18) Preparation of Copolymer Solution A-18 (Solution of SAH Adduct of Cures MOI Adduct of BzMI-CHMA-HEMA-GMA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 78.6 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 29.3 parts of cyclohexyl methacrylate, 40.0 parts of 2-hydroxyethyl methacrylate, 20.7 parts of glycidyl methacrylate, 10.0 parts of propylene glycol monomethyl ether acetate, and 6.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 48.00 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 4.8 parts of 2-isocyanatoethyl methacrylate (Karenz MOI (registered trademark) manufactured by Showa Denko KK) and 0.16 part of Antage W-400 were reacted at 90 °C for 8 hours. Then, after cooling to room temperature, 14.6 parts of succinic anhydride and 0.36 part of triethylamine as a catalyst were reacted at 60 °C for 10 hours to obtain copolymer solution A-18. The various physical properties of the obtained copolymer are shown in Table 1.

[0269] (Production Example 19) Preparation of Copolymer Solution B-1 (BzMI-CHMA-HEMA-Cyclomer M100-MAA Copolymer) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 145.3 parts of propylene glycol monomethyl ether acetate were charged. After nitrogen substitution, the mixture was heated to raise the temperature to 90 °C. On the other hand, as dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 47.4 parts of cyclohexyl methacrylate, 13.45 parts of 2-hydroxyethyl methacrylate, 20.25 parts of 3,4-epoxycyclohexylmethyl methacrylate (manufactured by Daicel Corporation, "Cyclomer M100 (registered trademark)"), 8.9 parts of methacrylic acid, 10.0 parts of propylene glycol monomethyl ether acetate, and 2.7 parts of t-butyl peroxypivalate (manufactured by Arkema Kishu Co., Ltd., "Luperox 11 (registered trademark)"). As dropping tank (B), a mixture of 2.0 parts of n-dodecyl mercaptan and 78 parts of propylene glycol monomethyl ether acetate was stirred and mixed. After the temperature of the reaction vessel reached 70 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 70 °C for 30 minutes after the completion of dropping, the temperature was raised to 80 °C and aging was carried out for 180 minutes to obtain copolymer solution B-1. The various physical properties of the obtained copolymer are shown in Table 1.

[0270] (Production Example 20) Preparation of Copolymer Solution B-2 (BzMI-CHMA-HEMA-GMA-MAA Copolymer) A reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet was charged with 145.3 parts of propylene glycol monomethyl ether acetate. After purging with nitrogen, the mixture was heated to 70 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 52.95 parts of cyclohexyl methacrylate, 13.45 parts of 2-hydroxyethyl methacrylate, 14.7 parts of glycidyl methacrylate, 8.9 parts of methacrylic acid, 10.0 parts of propylene glycol monomethyl ether acetate, and 2.7 parts of t-butyl peroxypivalate (Luperox 11 (registered trademark) manufactured by Arkema Kishida Co., Ltd.). As the dropping tank (B), a mixture of 2.0 parts of n-dodecyl mercaptan and 78 parts of propylene glycol monomethyl ether acetate was prepared by stirring and mixing. After the temperature of the reaction vessel reached 70 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining 70 °C for 30 minutes after the completion of dropping, the temperature was raised to 80 °C and aging was carried out for 180 minutes to obtain a copolymer solution B-2. Various physical properties of the obtained copolymer are shown in Table 1.

[0271]

Table 1

[0272] The descriptions in Table 1 are as follows. BzMI: N-benzylmaleimide AMA: Methyl α-(allyloxymethyl)acrylate MD: Dimethyl 2,2’-[oxybis(methylene)]bis-2-propenoate CHMI: N-cyclohexylmaleimide CHMA: Cyclohexyl methacrylate VT: Vinyltoluene 2EHA: 2-Ethylhexyl acrylate DCPMA: Dicyclopentanyl methacrylate TBMA: Tert-butyl methacrylate HEMA: 2-Hydroxyethyl methacrylate HEAA: N-Hydroxyethylacrylamide GLMA: Glycerin monomethacrylate M100: 3,4-Epoxycyclohexylmethyl methacrylate GMA: Glycidyl methacrylate NIPAM: N-Isopropylacrylamide MAA: Methacrylic acid AA: Acrylic acid Karenz MOI: 2-Methacryloyloxyethyl isocyanate SAH: Succinic anhydride

[0273] (Preparation of Pigment Dispersion 1) 12.9 parts of propylene glycol monomethyl ether acetate, 0.4 part of Disparon DA-7301 as a dispersant, 2.25 parts of C.I. Pigment Green 58 as a colorant, and 1.5 parts of C.I. Pigment Yellow 138 were mixed and dispersed for 3 hours using a paint shaker to obtain Pigment Dispersion 1 (solid content: 22% by mass).

[0274] (Example 1) Based on the solid content, 35.0 parts of copolymer solution A-1, 30.0 parts of dipentaerythritol hexaacrylate as a radically polymerizable compound, 5.0 parts of Irgacure OXE-02 (manufactured by BASF Japan Ltd.) as a radically polymerizable photoinitiator, 30.0 parts of Pigment Dispersion 1, and a diluting solvent (propylene glycol monomethyl ether acetate) were added to a solid content concentration of 20% and stirred to obtain Photosensitive Resin Composition 1.

[0275] (Examples 2 to 18, Comparative Examples 1 to 2) Photosensitive Resin Compositions 2 to 20 were obtained in the same manner as in Example 1 except that the formulations shown in Table 2 were used. The solvent resistance of the obtained Photosensitive Resin Compositions 1 to 20 was evaluated. The results are shown in Table 2.

[0276] [Table 2]

[0277] From Table 2, it was found that a photosensitive resin composition containing a copolymer having an epoxy group-containing structural unit and a long-chain acid group-containing structural unit and having an epoxy equivalent of 20,000 or less gives a cured product with good curability and excellent solvent resistance even under low-temperature curing conditions of 90 °C or 110 °C.

[0278] Example 19, Comparative Example 3 (Confirmation of storage stability) The following operation was carried out to examine the effect of storage stability by a diluent solvent. Using a copolymer solution prepared by adding 20 parts of a diluent solvent (corresponding to 66.7% by mass based on 100% by mass of the copolymer solid content) to 100 parts (as is) of the copolymer solution A-2, the physical property changes (weight average molecular weight and viscosity) of the copolymer were confirmed before and after storage at 40 °C for 2 weeks. Two types of diluent solvents, propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether, were used. The changes in the physical properties of the obtained copolymer solution are shown in Table 3. As the amount of change, for the weight average molecular weight, the ratio (%) of the difference in the weight average molecular weight before and after storage to the weight average molecular weight before storage was represented. For the viscosity, the ratio (%) of the difference in the viscosity before and after storage to the viscosity before storage was represented.

[0279] [Table 3]

[0280] From Table 3, it was found that when propylene glycol monomethyl ether, which is an alcohol-based solvent, was added, the amount of change in the weight average molecular weight and the amount of change in the viscosity after storage were smaller than those when propylene glycol monomethyl ether acetate was added, and the storage stability of the copolymer was excellent.

[0281] (Production Example 21) Preparation of copolymer solution A-19 Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 105.3 parts of propylene glycol monomethyl ether acetate were charged. After purging with nitrogen, the mixture was heated to raise the temperature to 90 °C. On the other hand, as the dropping tank (A), a beaker was prepared by stirring and mixing 10.0 parts of N-benzylmaleimide, 27.5 parts of cyclohexyl methacrylate, 30.0 parts of 2-hydroxyethyl methacrylate, 32.5 parts of glycidyl methacrylate, 30 parts of propylene glycol monomethyl ether acetate, and 2.0 parts of t-butylperoxy-2-ethylhexanoate (Perbutyl (registered trademark) O manufactured by NOF Corporation). As the dropping tank (B), a beaker was prepared by stirring and mixing 2.0 parts of n-dodecyl mercaptan and 98.0 parts of propylene glycol monomethyl ether acetate. After the temperature of the reaction vessel reached 90 °C, dropping was started from the dropping tank over 3 hours while maintaining the same temperature, and polymerization was carried out. After maintaining the temperature at 90 °C for 30 minutes after the completion of dropping, the temperature was raised to 115 °C and aging was carried out for 90 minutes. Then, after cooling to room temperature, 11.5 parts of succinic anhydride, 0.33 part of triethylamine as a catalyst, and 29.0 parts of propylene glycol monomethyl ether acetate were added and reacted at 60 °C for 7 hours. Then, 42.0 parts of propylene glycol monomethyl ether were added so that the solid content became 27%, and copolymer solution A-19 was obtained. Various physical properties of the obtained copolymer are shown in Table 4.

[0282] (Production Example 22) Preparation of Copolymer Solution A-20 Copolymer solution A-20 was obtained by the same preparation method as copolymer solution A-19, except that propylene glycol monomethyl ether acetate was added instead of propylene glycol monomethyl ether. Various physical properties of the obtained copolymer are shown in Table 4.

[0283] [Table 4]

[0284] Note that the descriptions in Table 4 are as follows. BzMI: N-benzylmaleimide CHMA: Cyclohexyl methacrylate HEMA: 2-Hydroxyethyl methacrylate GMA: Glycidyl methacrylate SAH: Succinic anhydride TEA: Triethylamine

[0285] (Example 20) In terms of solid content, 35.0 parts of copolymer solution A-19, 30.0 parts of dipentaerythritol hexaacrylate as a radically polymerizable compound, 5.0 parts of Irgacure OXE-02 (manufactured by BASF Japan Ltd.) as a radically polymerizable photoinitiator, 30.0 parts of pigment dispersion 1, 1.0 part of P-2M (Light Ester P-2M, pKa: 1.29, manufactured by Kyoeisha Chemical Co., Ltd.), and further a diluting solvent (propylene glycol monomethyl ether acetate) was added so that the solid content concentration became 20%, and the photosensitive resin composition 21 was obtained by stirring.

[0286] (Examples 21 to 23) Photosensitive resin compositions 22 to 24 were obtained in the same manner as in Example 20 except that the formulations shown in Table 5 were used. The solvent resistance of the obtained photosensitive resin compositions 21 to 24 was evaluated. The results are shown in Table 5.

[0287]

Table 5

[0288] From Table 5, it can be seen that a photosensitive resin composition containing a copolymer having an epoxy group-containing structural unit and an acid group-containing structural unit and an epoxy equivalent of 20,000 or less has good curability and excellent solvent resistance even under low-temperature curing conditions of 90°C.

[0289] Examples 24 to 40 (Confirmation of storage stability) To 100 parts (in terms of appearance) of the copolymer solution, a diluent solvent (propylene glycol monomethyl ether) and P-1M, P-2M, MSA, or ACA were added in the amounts described in Table 6 or Table 7 to prepare a copolymer solution. The amount of the diluent solvent corresponded to 129.6% by mass based on 100% by mass of the copolymer solid content in Table 6 (35 parts) and 29.6% by mass based on 100% by mass of the copolymer solid content in Table 7 (8 parts). Using the obtained copolymer solution, the physical property changes (viscosity) of the copolymer solution before and after storage at 40°C for 1 to 2 weeks were confirmed. The physical property changes of the obtained copolymer solution are shown in Table 6 and Table 7. The change amount of viscosity (thickening rate) was represented as the ratio (%) of the difference in viscosity before and after storage to the viscosity before storage. Also, the content of the acid compound (P-1M, P-2M, MSA, ACA) with respect to 100 mol% of the basic compound (TEA) in the copolymer solution was shown in the table.

[0290]

Table 6

[0291]

Table 7

[0292] Note that the descriptions in Table 6 and Table 7 are as follows. P-1M: Light Ester P-1M (manufactured by Kyoeisha Chemical Co., Ltd.) 2-methacryloyloxyethyl acid phosphate, pKa: 1.78, molecular weight: 210.12 P-2M: Light Ester P-2M (manufactured by Kyoeisha Chemical Co., Ltd.) 2-methacryloyloxyethyl acid phosphate, pKa: 1.29, molecular weight: 322.25 MSA: Methanesulfonic acid, pKa: -2.6, molecular weight: 96.1 ACA: Acetic acid, pKa: 4.76, molecular weight: 60.05

[0293] From Tables 6 and 7, in a copolymer solution containing a copolymer having an epoxy group-containing structural unit and an acid group-containing structural unit and having an epoxy equivalent of 20,000 or less, and a protic polar solvent, by further containing an acid compound having a pKa of 4.2 or less, it was confirmed that the thickening rate after storage becomes low and the storage stability is excellent.

Claims

1. It has an epoxy group-containing structural unit (A) represented by the following general formula (1), an acid group-containing structural unit (B) represented by the following general formula (2), and a structural unit (D) derived from a hydroxyl group-containing monomer, wherein the content ratio of the structural unit (D) is 1 to 50% by mass based on 100% by mass of all the structural units, and the epoxy equivalent is 100 or more and 20,000 or less, characterized in that it is a copolymer. 【Chemical 1】 (In formula (1), R １ represents a hydrogen atom or a methyl group. R ２ represents a direct bond or a divalent organic group. X represents an epoxy group-containing group.) 【Chemical Formula 2】 (In formula (2), R ３ represents a hydrogen atom or a methyl group. R ４ represents a direct bond or an organic group. R ５ represents a bonding chain having a length of two or more atoms, and represents -R-, -O-R-, -O-R-O-, -CO-R- or -O-R-O-CO-R'- . R and R' are the same or different and each represents a divalent aliphatic hydrocarbon group which may have a substituent. Y represents a carboxyl group, a phenolic hydroxyl group, a carboxylic anhydride group, a phosphoric acid group, or a sulfonic acid group. a represents 0 or 1.)

2. The copolymer according to claim 1, wherein the content ratio of the structural unit (A) is 0.1 to 50% by mass based on 100% by mass of all the structural units, and the content ratio of the structural unit (B) is 0.1 to 50% by mass based on 100% by mass of all the structural units.

3. The copolymer according to claim 1 or 2, wherein the weight average molecular weight of the copolymer is 4,000 or more and 20,000 or less.

4. The copolymer according to any one of claims 1 to 3, wherein the structural unit (A) contains a structural unit represented by the following general formula (1-1). 【Chemical Formula 3】 (In formula (1-1), R １ represents a hydrogen atom or a methyl group. R ６ represents a direct bond or a divalent organic group.)

5. The copolymer according to any one of claims 1 to 4, wherein the structural unit (B) contains a structural unit represented by the following general formula (2-1). 【Chemical Formula 4】 (In formula (2-1), R ３ represents a hydrogen atom or a methyl group. R ７ and R ８ are the same or different and each represents a direct bond or a divalent aliphatic hydrocarbon group which may have a substituent. b represents 0 or 1.)

6. The copolymer according to any one of claims 1 to 5, characterized in that the acid value is 30 mgKOH / g or more and 300 mgKOH / g or less.

7. The copolymer according to any one of claims 1 to 6, further characterized by having a structural unit (C) having a ring structure in the main chain.

8. The copolymer according to claim 7, wherein the content ratio of the structural unit (C) is 0.1 to 50% by mass based on 100% by mass of all the structural units.

9. A curable resin composition comprising the copolymer according to any one of claims 1 to 8 and a polymerizable compound.

10. The curable resin composition according to claim 9, further characterized by containing a coloring material.

11. A cured product of the curable resin composition according to claim 10.

12. A member for a display device, characterized by having the cured product according to claim 11.

13. A method for producing a copolymer having an epoxy equivalent of 100 or more and 20,000 or less, comprising a step of polymerizing a monomer component containing an epoxy group-containing monomer represented by the following formula (a) and a hydroxyl group-containing monomer represented by the following formula (b1), and a step of reacting the polymer obtained in the polymerization step with an acid group-containing compound represented by the following formula (b3) in the presence of a basic compound. The copolymer has a structural unit derived from the hydroxyl group-containing monomer A method for producing a copolymer, characterized by the above. 【Chemical Formula 5】 (In formula (a), R １ represents a hydrogen atom or a methyl group. R ２ represents a direct bond or a divalent organic group. X represents an epoxy group-containing group.) [Chemical Formula 6] (In formula (b1), R ３ represents a hydrogen atom or a methyl group. R ４ represents a direct bond or an organic group.) 【Chemical Formula 7】 (In formula (b3), R ５ represents a bonding chain having a length of two or more atoms, and represents -R-, -O-R-, -O-R-O-, -CO-R- or -O-R-O-CO-R'- R and R' are the same or different and each represents a divalent aliphatic hydrocarbon group which may have a substituent.)

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