N-substituted maleimide polymer and method for producing same

Abstract

To provide a method for producing an N-substituted maleimide polymer with which it is possible to obtain a polymer in which thermal discoloration is significantly suppressed when a polymer is produced using an N-substituted maleimide monomer and glycidyl (meth)acrylate.SOLUTION: A method for producing an N-substituted maleimide polymer includes a step (I-2) for polymerizing a monomer component that includes an N-substituted maleimide monomer (a) and an unsaturated carboxylic acid monomer (b) to obtain a base polymer, and a step (I-3) for reacting glycidyl (meth)acrylate that has been adjusted to have a chlorine content of 0.01-0.3 mass% with the base polymer to obtain an N-substituted maleimide polymer having a double bond in a side chain.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing an N-substituted maleimide polymer and an N-substituted maleimide polymer obtained by the method. More specifically, the present invention relates to an N-substituted maleimide polymer capable of suppressing thermal discoloration of a cured product, and a method for producing the same. [Background technology]

[0002] N-substituted maleimide polymers are polymers obtained by polymerizing monomer components containing N-substituted maleimide monomers such as N-benzylmaleimide and N-phenylmaleimide. Such maleimide polymers generally have high glass transition temperatures and excellent heat resistance, and are therefore widely used as optical materials and electrical / electronic materials.

[0003] It is also known to introduce a polymerizable double bond into the side chain of a polymer in order to improve the crosslinkability and crosslink density of the polymer. Such a polymer having a polymerizable double bond in the side chain can be obtained, for example, by polymerizing a monomer component containing a monomer having an acid group to obtain a base polymer, and then subjecting the polymer to an addition reaction with a compound having an epoxy group and a polymerizable double bond to introduce the polymer into the polymer, or by polymerizing a monomer component containing a compound having an epoxy group and a polymerizable double bond to obtain a base polymer, and then reacting the polymer with a compound having an acid group and a polymerizable double bond to introduce the polymer into the polymer. When producing such a polymer having a polymerizable double bond in the side chain, glycidyl (meth)acrylate (glycidyl acrylate and / or glycidyl methacrylate) is used as one of the compounds having an epoxy group and a polymerizable double bond.

[0004] For example, Patent Document 1 describes a photosensitive resin composition for color filters containing a carboxyl group-containing radically polymerizable copolymer having an ethylenically unsaturated double bond, and describes a method for obtaining the radically polymerizable copolymer, in which an epoxy group-containing ethylenically unsaturated compound is reacted with a copolymer obtained using an N-substituted maleimide compound and an unsaturated carboxylic acid compound such as (meth)acrylic acid (acrylic acid and / or methacrylic acid) as monomer components. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-32772 Summary of the Invention [Problem to be solved by the invention]

[0006] However, polymers obtained using glycidyl (meth)acrylate have the problem of being easily discolored by heat, depending on their structure. In particular, when glycidyl (meth)acrylate is mixed with an N-substituted maleimide monomer or a polymer containing a structural unit derived from an N-substituted maleimide monomer and heated, the resulting cured product becomes significantly discolored by heat (thermal discoloration). Such discoloration becomes a major problem when it is desired to use the N-substituted maleimide polymer in the production of light-colored or transparent products.

[0007] In view of the above-mentioned current situation, an object of the present invention is to provide a method for producing an N-substituted maleimide polymer, which can give a polymer with significantly reduced thermal discoloration when the polymer is produced using an N-substituted maleimide monomer and glycidyl (meth)acrylate. [Means for solving the problem]

[0008]

[0003] In order to solve the above-mentioned problems, the present inventors have investigated various methods for producing polymers using glycidyl (meth)acrylate and N-substituted maleimide monomers, and have found that glycidyl (meth)acrylate contains chlorine as an impurity, and that the chlorine promotes the thermal oxidation of the maleimide group, resulting in thermal discoloration of the resulting polymer. The present inventors have then found that by using glycidyl (meth)acrylate with a chlorine content within a predetermined range, for example, by using glycidyl (meth)acrylate with a chlorine content adjusted to fall within a predetermined range, an N-substituted maleimide polymer having a double bond in the side chain and in which thermal discoloration is significantly suppressed can be obtained, and have thus completed the present invention.

[0009] That is, the present invention provides a method for producing an N-substituted maleimide polymer, comprising: a step (I-2) of polymerizing a monomer component containing an N-substituted maleimide monomer (a) and an unsaturated carboxylic acid monomer (b) to obtain a base polymer; and a step (I-3) of reacting the base polymer with glycidyl (meth)acrylate, the chlorine content of which has been adjusted to 0.01 to 0.3 mass %, to obtain an N-substituted maleimide polymer having a double bond in the side chain.

[0010] The method for producing the N-substituted maleimide polymer preferably further comprises, before the step (I-2), a step (I-1) of purifying the glycidyl (meth)acrylate so that the chlorine content in the glycidyl (meth)acrylate is 0.01 to 0.3 mass %.

[0011] The present invention also provides a method for producing an N-substituted maleimide polymer, comprising: a step (II-2) of polymerizing a monomer component containing an N-substituted maleimide monomer (a) and glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3 mass % to obtain a base polymer; and a step (II-3) of reacting the base polymer with an unsaturated carboxylic acid monomer (b) to obtain an N-substituted maleimide polymer having a double bond in a side chain.

[0012] The method for producing the N-substituted maleimide polymer preferably further comprises, before the step (II-2), a step (II-1) of purifying the glycidyl (meth)acrylate so that the chlorine content in the glycidyl (meth)acrylate is 0.01 to 0.3 mass %.

[0013] The method for producing the N-substituted maleimide polymer preferably further comprises, after the step (II-3), a step (II-4) of reacting the N-substituted maleimide polymer having a double bond in a side chain with a polybasic acid or a polybasic acid anhydride.

[0014] In the method for producing the N-substituted maleimide polymer, the amount of residual chlorine in the N-substituted maleimide polymer is preferably 100 to 2000 ppm based on the total amount of the N-substituted maleimide monomer (a) and glycidyl (meth)acrylate used.

[0015] The present invention also relates to an N-substituted maleimide polymer having a structural unit (A) derived from an N-substituted maleimide monomer and a structural unit (B) represented by the following general formula (B1), (B2), or (B3), wherein the structural unit (B) contains a structure derived from glycidyl (meth)acrylate, and the amount of residual chlorine in the N-substituted maleimide polymer is 100 to 2000 ppm relative to the total mass of the N-substituted maleimide monomer that provides the structural unit (A) and the glycidyl (meth)acrylate that provides the structural unit (B), which are raw materials for the polymer.

[0016] [ka]

[0017] (In general formula (B1), R 1 and R 3 are the same or different and represent a hydrogen atom or a methyl group. 2 represents a divalent linking group. a is 0 or 1. In general formula (B2), R 4 represents a hydrogen atom or a methyl group. 5represents an ethylenically unsaturated bond-containing group. In general formula (B3), R 6 represents a hydrogen atom or a methyl group. 7 represents an ethylenically unsaturated bond-containing group. X represents a divalent hydrocarbon group.

[0018] The N-substituted maleimide polymer preferably has an acid value of 20 to 200 mgKOH / g.

[0019] The N-substituted maleimide polymer preferably has a double bond equivalent of 300 to 3000 g / equivalent.

[0020] The present invention also relates to a curable resin composition comprising the above-mentioned N-substituted maleimide polymer and a polymerizable compound. [Effects of the Invention]

[0021] According to the present invention, an N-substituted maleimide polymer having a double bond in the side chain and exhibiting significantly reduced thermal coloration can be suitably obtained. The N-substituted maleimide polymer of the present invention can be suitably used as an optical material, an electric / electronic material, etc. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in detail below. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention. In this specification, "(meth)acrylic acid" means "acrylic acid" and "methacrylic acid", and "(meth)acrylate" means "acrylate" and "methacrylate".

[0023] 1. Method for producing N-substituted maleimide polymer The present invention provides a method (I) for producing an N-substituted maleimide polymer, comprising: a step (I-2) of polymerizing monomer components containing an N-substituted maleimide monomer (a) and an unsaturated carboxylic acid monomer (b) to obtain a base polymer; and a step (I-3) of reacting the base polymer with glycidyl (meth)acrylate, the chlorine content of which has been adjusted to 0.01 to 0.3 mass %, to obtain an N-substituted maleimide polymer having a double bond in the side chain.

[0024] The present invention also relates to a method (II) for producing an N-substituted maleimide polymer, comprising: a step (II-2) of polymerizing a monomer component containing an N-substituted maleimide monomer (a) and glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3% by mass to obtain a base polymer; and a step (II-3) of reacting the base polymer with an unsaturated carboxylic acid monomer (b) to obtain an N-substituted maleimide polymer having a double bond in the side chain.

[0025] In both of the methods (I) and (II) for producing an N-substituted maleimide polymer of the present invention, glycidyl (meth)acrylate with a chlorine content adjusted to 0.01 to 0.3% by mass is used. The use of glycidyl (meth)acrylate with a chlorine content adjusted to 0.01 to 0.3% by mass significantly suppresses thermal discoloration of the resulting polymer, presumably for the following reason: It is believed that chlorine contained as an impurity in glycidyl (meth)acrylate generates hydrogen chloride and hypochlorous acid upon heating, promoting the generation of amines from the N-substituted maleimide, and the generated amines are oxidized by oxidizing substances such as hypochlorous acid to generate colored substances; and it is believed that the generation of such colored substances is significantly suppressed by controlling the residual chlorine content in glycidyl (meth)acrylate to a predetermined range.

[0026] The method for producing an N-substituted maleimide polymer of the present invention can ultimately produce an N-substituted maleimide polymer having a double bond in the side chain. The presence of a double bond in the side chain increases the crosslinkability of the N-substituted maleimide polymer and increases the crosslink density. The double bond means a polymerizable double bond, that is, a carbon-carbon double bond, and examples thereof include a (meth)acryloyl group, a vinyl group, an allyl group, and a methallyl group. The methods (I) and (II) for producing the N-substituted maleimide polymer of the present invention will be described in detail below.

[0027] 1-1. Manufacturing method (I) <Process (I-2)> The above-mentioned production method (I) includes a step (I-2) of polymerizing a monomer component containing an N-substituted maleimide monomer (a) and an unsaturated carboxylic acid monomer (b) to obtain a base polymer (also referred to as "base polymer 1").

[0028] The method for polymerizing the monomer components containing the monomers (a) and (b) to obtain the base polymer 1 is not particularly limited, and examples thereof include known polymerization methods such as bulk polymerization, solution polymerization, and emulsion polymerization. Among these, solution polymerization is preferred because it is industrially advantageous and allows for easy structural adjustment such as molecular weight. Furthermore, the polymerization mechanism of the monomer components can be based on a polymerization method based on a mechanism such as radical polymerization, anionic polymerization, cationic polymerization, or coordination polymerization, but a polymerization method based on a radical polymerization mechanism is preferred because of its industrial advantages.

[0029] The molecular weight of the base polymer 1 obtained by polymerizing the above-mentioned monomer components can be controlled by adjusting the amount and type of the polymerization initiator, the polymerization temperature, the type and amount of the chain transfer agent, and the like.

[0030] Examples of the polymerization initiator include peroxides and azo compounds that are commonly used as polymerization initiators, such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-butylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, azobisisobutyronitrile, 1,1′-azobis(cyclohexanecarbonitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis(2-methylpropionate), hydrogen peroxide, and persulfates.

[0031] Preferred examples of the chain transfer agent include compounds having a mercapto group, such as mercaptocarboxylic acids, mercaptocarboxylic acid esters, alkyl mercaptans, mercaptoalcohols, aromatic mercaptans, and mercaptoisocyanurates, more preferably alkyl mercaptans, mercaptocarboxylic acids, and mercaptocarboxylic acid esters, and even more preferably n-dodecyl mercaptan and mercaptopropionic acid.

[0032] The solvent used in the polymerization is not particularly limited, and examples thereof include monoalcohols such as methanol, ethanol, isopropanol, n-butanol, and s-butanol; polyhydric alcohols such as ethylene glycol and propylene glycol; 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.

[0033] The polymerization initiator, chain transfer agent, and solvent may each be used alone or in combination of two or more kinds, and the amounts used can be set appropriately.

[0034] The polymerization temperature can be appropriately set depending on the type and amount of the monomers used, the type and amount of the polymerization initiator, etc., but is preferably 50 to 200°C, and more preferably 80 to 120°C. The polymerization time can be set as appropriate, but is preferably 1 to 12 hours, more preferably 3 to 8 hours, for example.

[0035] The mixing of the monomer components is not particularly limited and may be carried out appropriately depending on the N-substituted maleimide polymer to be obtained. The entire amounts of the monomers (a) and (b) may be mixed at the same time, or the monomer (b) or (a) may be added little by little to the entire amount of the monomer (a) or (b) and mixed.

[0036] After the above-mentioned monomer components are polymerized to obtain base polymer 1, the volatile components may be removed from the polymerization reaction liquid (polymer solution) to separate base polymer 1, and then base polymer 1 may be used, or it may be used in solution form without separation. However, for industrial use, it is preferable to use it in solution form without separation from the standpoint of cost, etc.

[0037] The monomer components used in the production of the N-substituted maleimide polymer are described below. By polymerizing the monomer components containing each monomer, a copolymer having structural units derived from each monomer can be obtained.

[0038] (N-substituted maleimide monomer (a)) Examples of the N-substituted maleimide monomer (a) include compounds represented by the following general formula (a):

[0039] [ka] (In the formula, R 8represents a monovalent hydrocarbon group having 1 to 30 carbon atoms, which may have a substituent.

[0040] In general formula (a), R 8 is a monovalent hydrocarbon group having 1 to 30 carbon atoms, which may have a substituent. The monovalent hydrocarbon group preferably has 1 to 20 carbon atoms, and more preferably has 6 to 12 carbon atoms. The hydrocarbon group may be a chain or cyclic aliphatic hydrocarbon group, or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, but is preferably a saturated aliphatic hydrocarbon group.

[0041] Examples of the chain saturated aliphatic hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a hexyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, a heptyl group, a 2-methylhexyl group, a 3-methylhexyl group, a 2,2-dimethylpentyl group, a 2,3-dimethylpentyl group, a 2,4-dimethylpentyl group, a 3-ethylpentyl group, and a 2,2,3-trimethylpentyl group. and linear or branched alkyl groups such as butyl, octyl, methylheptyl, dimethylhexyl, 2-ethylhexyl, 3-ethylhexyl, trimethylpentyl, 3-ethyl-2-methylpentyl, 2-ethyl-3-methylpentyl, 2,2,3,3-tetramethylbutyl, nonyl, methyloctyl, 3,7-dimethyloctyl, dimethylheptyl, 3-ethylheptyl, 4-ethylheptyl, trimethylhexyl, 3,3-diethylpentyl, decyl, undecyl, and dodecyl groups. Of these, alkyl groups having 1 to 30 carbon atoms are preferred, alkyl groups having 1 to 20 carbon atoms are more preferred, and alkyl groups having 1 to 12 carbon atoms are even more preferred.

[0042] Examples of cyclic aliphatic hydrocarbon groups include monocyclic alicyclic hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and a cyclododecyl group; and polycyclic alicyclic hydrocarbon groups such as a dicyclopentanyl group, a norbornyl group, and an adamantyl group. Among these, a monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 30 carbon atoms is preferred, a monocyclic or polycyclic alicyclic hydrocarbon group having 3 to 18 carbon atoms is more preferred, and a monocyclic alicyclic hydrocarbon group having 6 to 12 carbon atoms is even more preferred.

[0043] Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a benzyl group, a phenethyl group, etc. Among these, an aromatic hydrocarbon group having 6 to 30 carbon atoms is preferred, and an aromatic hydrocarbon group having 6 to 12 carbon atoms is more preferred.

[0044] The hydrocarbon group may have a substituent, such as an alkyl group, an aryl group, a hydroxyl group, a halogen atom, a carboxyl group, an alkoxy group, or an aryloxy group.

[0045] Specific examples of the N-substituted maleimide monomer include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, Nt-butylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-octylmaleimide, N-2-ethylhexylmaleimide, N-decylmaleimide, N-laurylmaleimide, N-tetradecylmaleimide, N-stearylmaleimide, N-2-decyltetradecylmaleimide, and N-phenylmaleimide. Examples of the maleimide include N-benzylmaleimide, N-naphthylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-hydroxylethylmaleimide, N-hydroxylphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, N-tribromophenylmaleimide, N,N'-o-phenylenebismaleimide, N,N'-metaphenylenebismaleimide, and N,N'-paraphenylenebismaleimide. Among these, from the viewpoints of copolymerizability with the N-vinylamide monomer and heat resistance, N-benzylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide are preferred, N-benzylmaleimide and N-cyclohexylmaleimide are more preferred, and N-benzylmaleimide is even more preferred. In particular, N-benzylmaleimide is preferably used in applications where heat coloration resistance is highly required, and N-phenylmaleimide is preferably used in applications where affinity with organic or inorganic fine particles is highly required.

[0046] 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.

[0047] The N-substituted maleimide monomer (a) may be used alone or in combination of two or more.

[0048] Among these, the N-substituted maleimide monomer (a) is preferably N-benzylmaleimide or N-phenylmaleimide, as the combination of these two types may improve the dispersion stability of the pigment and increase the surface hardness of the cured film. The mass ratio of N-benzylmaleimide to N-phenylmaleimide is preferably 95 / 5 to 5 / 95, and more preferably 10 / 90 to 90 / 10.

[0049] Furthermore, when N-phenylmaleimide is used as the main component of the N-substituted maleimide monomer (a), the proportion of N-benzylmaleimide is preferably 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, even more preferably 1 to 10 parts by mass, and most preferably 1 to 5 parts by mass, relative to 100 parts by mass of N-phenylmaleimide.

[0050] Furthermore, the amount of N-benzylmaleimide used is preferably 0.5 to 10 mass%, more preferably 0.5 to 5 mass%, even more preferably 0.5 to 3 mass%, particularly preferably 0.5 to 2 mass%, and most preferably 0.5 to 1.8 mass%, relative to 100 mass% of the total monomer components. By setting the content within the above range, the affinity and dispersibility with organic fine particles such as pigments and inorganic fine particles such as quantum dots or silica can be improved.

[0051] (Unsaturated Carboxylic Acid Monomer (b)) The unsaturated carboxylic acid monomer (b) may be a compound having a carboxyl group and / or a carboxylic anhydride group and a polymerizable double bond. Examples of the polymerizable double bond include a (meth)acryloyl group, a vinyl group, an allyl group, a methallyl group, etc. Of these, a (meth)acryloyl group is preferred.

[0052] Specific examples of the unsaturated carboxylic acid 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 long-chain monocarboxylic acids in which the unsaturated group and the carboxyl group are chain-extended, such as mono(2-acryloyloxyethyl) succinate and mono(2-methacryloyloxyethyl) succinate; and unsaturated acid anhydrides such as maleic anhydride and itaconic anhydride. Among these, from the viewpoints of versatility, availability, and the like, unsaturated monocarboxylic acids are preferred, and (meth)acrylic acid is more preferred. The unsaturated carboxylic acid monomer (b) may be used singly or in combination of two or more kinds.

[0053] (Monomer (c) copolymerizable with the above monomer (a) and monomer (b)) The monomer components for producing base polymer 1 may further contain, in addition to the above-mentioned monomer (a) and monomer (b), a monomer (c) that is copolymerizable with the above-mentioned monomer (a) and monomer (b). The monomer (c) is not particularly limited as long as it is copolymerizable with the above-mentioned monomers (a) and (b), and examples thereof include the following monomers: These may be used alone or in combination of two or more.

[0054] hydroxyl group-containing monomers such as 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;

[0055] Methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-amyl (meth)acrylate, s-amyl (meth)acrylate, t-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, 2-methoxyethyl (meth)acrylate, 2-methylpropional (meth)acrylate (meth)acrylic acid esters such as -ethoxyethyl, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, N,N-dimethylaminoethyl (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, and 4-(meth)acryloyloxymethyl-2,2-dimethyl-1,3-dioxolane;

[0056] Cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, pentacyclopentadecane dimethacrylate alicyclic (meth)acrylates such as norbornane dimethanol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, norbornane dimethanol di(meth)acrylate, p-menthane-1,8-diol di(meth)acrylate, p-menthane-2,8-diol di(meth)acrylate, p-menthane-3,8-diol di(meth)acrylate, and bicyclo[2.2.2]-octane-1-methyl-4-isopropyl-5,6-dimethylol di(meth)acrylate;

[0057] Epoxy group-containing monomers other than glycidyl (meth)acrylate, such as β-methylglycidyl (meth)acrylate, β-ethylglycidyl (meth)acrylate, vinylbenzyl glycidyl ether, allyl glycidyl ether, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and vinylcyclohexene oxide;

[0058] (Meth)acrylamides such as N,N-dimethyl(meth)acrylamide and N-methylol(meth)acrylamide; 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; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, 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; aromatic vinyls such as styrene, vinyltoluene, α-methylstyrene, xylene, methoxystyrene, and ethoxystyrene; unsaturated isocyanates such as isocyanatoethyl (meth)acrylate and allyl isocyanate; α-allyloxymethylacrylic acid, methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, and α - α-(unsaturated alkoxyalkyl)acrylate monomers such as n-propyl 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, and neopentyl α-allyloxymethylacrylate;Dialkyl-2,2'-(oxydimethylene) diacrylate monomers such as dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, diethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, dicyclohexyl-2,2'-[oxybis(methylene)]bis-2-propenoate, and dibenzyl-2,2'-[oxybis(methylene)]bis-2-propenoate; etc.;

[0059] The content of each of the above monomers (a), (b) and (c) can be appropriately set depending on the purpose and application of the N-substituted maleimide polymer to be obtained. The content of the above-mentioned monomer (a) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to 100% by mass of the total monomer components, and is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. The content of the above monomer (b) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to 100% by mass of the total monomer components, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. The content of the above monomer (c) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, relative to 100% by mass of the total monomer components, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When two or more kinds of monomers (a), (b), and (c) are contained, the content of each of the above monomers (a), (b), and (c) is the total amount thereof.

[0060] <Process (I-3)> The production method (I) further includes a step (I-3) of reacting the base polymer 1 obtained in the step (I-2) with glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3 mass % to obtain an N-substituted maleimide polymer having a double bond in the side chain.

[0061] The chlorine content of the glycidyl (meth)acrylate used in the above-mentioned production method (I) is 0.01 to 0.3% by mass. By using glycidyl (meth)acrylate adjusted to the above range, an N-substituted maleimide polymer with a small amount of residual chlorine can be produced, and thermal discoloration of the polymer can be suppressed. In addition, the polymer can be produced safely.

[0062] The chlorine content of the glycidyl (meth)acrylate is preferably 0.25% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.15% by mass or less, in order to further suppress thermal discoloration of the resulting N-substituted maleimide polymer. On the other hand, adjusting the glycidyl (meth)acrylate so that the chlorine content is less than 0.01% by mass is not preferable because it requires excessively large preparation equipment for purification, etc., and there is a risk of equipment blockage due to polymerization of glycidyl (meth)acrylate during purification distillation, a decrease in purification yield, etc., which is industrially disadvantageous. From the viewpoint of production costs, the lower limit of the chlorine content is preferably 0.03% by mass or more, more preferably 0.05% by mass or more. The amount of chlorine contained can be determined by measurement using ICP-MS (inductively coupled plasma mass spectrometry), specifically by the method described in the examples below.

[0063] A preferred method for adjusting the chlorine content of the glycidyl (meth)acrylate is, for example, a method of purifying glycidyl (meth)acrylate. The method for purifying the glycidyl (meth)acrylate is not particularly limited, and includes known methods such as distillation, extraction, and column chromatography. Among these, distillation is preferred because it allows chlorine to be removed easily and safely.

[0064] The distillation is not particularly limited, and examples thereof include known distillation methods such as simple distillation, precision distillation (rectification), distillation under reduced pressure (vacuum distillation), molecular distillation, and steam distillation. Among these, precision distillation is preferred in that it can easily produce a high purity industrially, and precision distillation under reduced pressure is more preferred.

[0065] The distillation method is not particularly limited and can be a known method, such as a vacuum concentration apparatus such as an evaporator, simple distillation, or precision distillation using a rectification column.

[0066] The distillation temperature is preferably 30° C. or higher, more preferably 40° C. or higher, and even more preferably 50° C. or higher, from the viewpoint of industrial ease of condensation and collection. The distillation temperature is preferably 150° C. or lower, more preferably 100° C. or lower, and even more preferably 80° C. or lower, from the viewpoint of suppressing polymerization during distillation and preventing clogging of the apparatus.

[0067] The distillation is preferably carried out under reduced pressure, for example, at 40,000 Pa or less, preferably 10,000 Pa or less, and more preferably 3,000 Pa or less. Examples of the method for carrying out the distillation under reduced pressure include known methods such as precision distillation using a rectification column.

[0068] The rectification column used for the distillation preferably has a theoretical plate number of 2 to 100, more preferably 5 to 50. If the reduction of the chlorine content by distillation is insufficient, the chlorine content can be reduced to the desired range by repeating the distillation multiple times. The number of times the distillation is repeated is preferably 3 or less, more preferably 2 or less. Repeating the distillation four or more times not only requires excessive equipment and processes, but also reduces the distillation yield, which is industrially disadvantageous.

[0069] During the distillation, a polymerization inhibitor or the like may be added to glycidyl (meth)acrylate. Adding a polymerization inhibitor can prevent polymerization during distillation. Examples of the polymerization inhibitor include those commonly used for radically polymerizable monomers, such as phenolic inhibitors such as hydroquinone, methylhydroquinone, trimethylhydroquinone, t-butylhydroquinone, methoquinone, 6-t-butyl-2,4-xylenol, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methoxyphenol, and 2,2'-methylenebis(4-methyl-6-t-butylphenol), as well as organic acid copper salts and phenothiazine. These may be used alone or in combination of two or more. Among these, phenolic inhibitors are preferred, with methoquinone, 6-t-butyl-2,4-xylenol, and 2,2'-methylenebis(4-methyl-6-t-butylphenol) being more preferred.

[0070] Before and / or after the distillation, the glycidyl (meth)acrylate may be washed with a solvent such as water or weak alkaline water, or may be dried or dehydrated to further remove impurities. If a large amount of water is contained, the glycidyl group of the glycidyl (meth)acrylate may be hydrolyzed. The water content is preferably 0.2 parts by mass or less, more preferably 0.1 parts by mass or less, and most preferably 0.05 parts by mass or less, per 100 parts by mass of the glycidyl (meth)acrylate.

[0071] Thus, the production method (I) of the present invention preferably includes, before the step (I-2) or (I-3), a step (I-1) of purifying glycidyl (meth)acrylate so that the chlorine content of the glycidyl (meth)acrylate is 0.01 to 0.3 mass%.

[0072] The method for reacting the glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3 mass% with the base polymer 1 is not particularly limited, and it is possible to mix the glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3 mass% with a polymer solution containing the base polymer 1 and react them by a known method. Through the reaction, the acid group (carboxyl group) of the base polymer 1 reacts with the epoxy group of the glycidyl (meth)acrylate, and the glycidyl (meth)acrylate is added to the base polymer 1, thereby obtaining a polymer having a terminal polymerizable double bond.

[0073] The temperature of the addition reaction is not particularly limited as long as it is a temperature at which the addition reaction proceeds, but may be, for example, 60 to 150°C, preferably 90 to 140°C, and more preferably 100 to 120°C.

[0074] The reaction time for the addition reaction is not particularly limited, but may be, for example, 1 to 48 hours, preferably 3 to 24 hours, and more preferably 6 to 12 hours.

[0075] The amount of the prepared glycidyl (meth)acrylate used in step (I-3) is preferably set appropriately so that the double bond equivalent of the resulting N-substituted maleimide polymer falls within a desired range. For example, the amount is preferably 1 to 150 parts by mass, more preferably 10 to 100 parts by mass, and even more preferably 15 to 80 parts by mass, relative to 100 parts by mass of the total monomer components that give base polymer 1.

[0076] In the addition reaction, known catalysts may be used, such as amine compounds such as trimethylamine, triethylamine, triisopropylamine, tributylamine, dimethylbenzylamine, methyldibenzylamine, and tribenzylamine; phosphines such as triethylphosphine and triphenylphosphine; ammonium salts such as tetraethylammonium chloride; phosphonium salts such as tetraphenylphosphonium bromide; and amide compounds such as dimethylformamide. Among these, amine compounds and phosphines are preferred in terms of little coloration and ease of industrial availability, and triethylamine, dimethylbenzylamine, and triphenylphosphine are more preferred.

[0077] The amount of the catalyst used can be set as appropriate, but is preferably 0.05 to 5% by mass, more preferably 0.1 to 1% by mass, and even more preferably 0.1 to 0.5% by mass, based on the total amount of base polymer 1 and the prepared glycidyl (meth)acrylate. If the amount of the catalyst used is below the above range, the reaction time may be prolonged, which may be industrially disadvantageous. If the amount exceeds the above range, the catalyst may form a salt with the base polymer when added, resulting in insolubilization and making stirring difficult, or the resulting polymer may become strongly colored by heat.

[0078] The above-mentioned production method (I) may include other steps in addition to the above-mentioned steps (I-1), (I-2), and (I-3). Examples of the other steps include an aging step, a neutralization step, a step of deactivating the polymerization initiator or chain transfer agent, a dilution step, a drying step, a concentration step, and a purification step. These steps can be carried out by known methods.

[0079] As described above, the above production method (I) preferably includes a step of adjusting the chlorine content of the glycidyl (meth)acrylate used to fall within a predetermined range. Therefore, a preferred embodiment of the present invention is a method for producing an N-substituted maleimide polymer, which comprises the steps of: (I-1) purifying glycidyl (meth)acrylate so that the chlorine content in the glycidyl (meth)acrylate is 0.01 to 0.3% by mass; (I-2) polymerizing a monomer component containing an N-substituted maleimide monomer (a) and an unsaturated carboxylic acid monomer (b) to obtain a base polymer; and (I-3) reacting the purified glycidyl (meth)acrylate obtained in step (I-1) with the base polymer to obtain an N-substituted maleimide polymer having a double bond in its side chain. The purified glycidyl (meth)acrylate obtained in step (I-1) is the glycidyl (meth)acrylate with a chlorine content adjusted to 0.01 to 0.3% by mass.

[0080] 1-2. Manufacturing method (II) <Process (II-2)> The above-mentioned production method (II) includes a step (II-2) of polymerizing a monomer component containing an N-substituted maleimide monomer (a) and glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3 mass % to obtain a base polymer (also referred to as "base polymer 2").

[0081] Examples of the N-substituted maleimide monomer (a) and the glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3% by mass include the same as the "N-substituted maleimide monomer (a)" and the "glycidyl (meth)acrylate having a chlorine content adjusted to 0.01 to 0.3% by mass" described in the above production method (I), respectively.

[0082] The monomer components for producing the base polymer 2 may further contain a monomer (d) copolymerizable with the monomer (a) and the prepared glycidyl (meth)acrylate. Examples of the monomer (d) include the same monomers as the monomer (c) described in the above production method (I), which may be used alone or in combination of two or more.

[0083] The polymerization method is not particularly limited, but preferred examples include the same polymerization method as described in the above production method (I).

[0084] The contents of the monomer (a), the prepared glycidyl (meth)acrylate, and the monomer (d) can be appropriately set depending on the purpose and application of the N-substituted maleimide polymer to be obtained. The content of the above-mentioned monomer (a) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to 100% by mass of the total monomer components, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0085] The amount of the prepared glycidyl (meth)acrylate is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to 100% by mass of the total monomer components, and is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 60% by mass or less.

[0086] The content of the above monomer (d) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to 100% by mass of the total monomer components, and is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. When two or more types of monomers are contained, the content of each of the monomer (a), the prepared glycidyl (meth)acrylate, and the monomer (d) is the total amount thereof.

[0087] The production method (II) of the present invention preferably includes, before the step (II-2), a step (II-1) of purifying glycidyl (meth)acrylate so that the chlorine content of the glycidyl (meth)acrylate is 0.01 to 0.3 mass %. The step (II-1) is preferably the same as the step (I-1) in the above-mentioned production method (I).

[0088] <Process (II-3)> The production method (II) further includes a step (II-3) of reacting the base polymer 2 obtained in the step (II-2) with an unsaturated carboxylic acid monomer (b) to obtain an N-substituted maleimide polymer having a double bond in the side chain.

[0089] The method for reacting the unsaturated carboxylic acid monomer (b) with the base polymer 2 is not particularly limited, and it is preferable to mix the unsaturated carboxylic acid monomer (b) and, if necessary, a polymerization initiator, a chain transfer agent, etc., with a polymer solution containing the base polymer 2 and react them by a known method. By the above reaction, the carboxyl group of the unsaturated carboxylic acid monomer (b) reacts with the epoxy group of the base polymer 2, and the unsaturated carboxylic acid monomer (b) is added to the base polymer 2, thereby obtaining an N-substituted maleimide polymer having a polymerizable double bond at its terminal. Examples of the unsaturated carboxylic acid monomer (b) include the same unsaturated carboxylic acid monomer (b) as described in the above production method (I).

[0090] The reaction temperature is not particularly limited as long as it is a temperature at which the above reaction proceeds, but may be, for example, 40 to 200°C, preferably 60 to 150°C, and more preferably 80 to 120°C.

[0091] The reaction time is not particularly limited, but may be, for example, 1 to 48 hours, preferably 3 to 24 hours, and more preferably 5 to 12 hours.

[0092] The amount of the unsaturated carboxylic acid monomer (b) used in the step (II-3) is preferably set appropriately so that the double bond equivalent of the resulting N-substituted maleimide polymer falls within a desired range. For example, the amount is preferably 1 to 50 parts by mass, more preferably 5 to 45 parts by mass, and even more preferably 10 to 40 parts by mass, relative to 100 parts by mass of the monomer component that gives the base polymer 2.

[0093] In the above reaction, known catalysts may be used, such as amine compounds such as triethylamine and dimethylbenzylamine, ammonium salts such as tetraethylammonium chloride, phosphonium salts such as tetraphenylphosphonium bromide, and amide compounds such as dimethylformamide. The amount of the catalyst used can be appropriately determined.

[0094] As described above, the above production method (II) preferably includes a step of adjusting the chlorine content of the glycidyl (meth)acrylate used to fall within a predetermined range. Therefore, a preferred embodiment of the present invention is a method for producing an N-substituted maleimide polymer, comprising the steps of: (1) purifying glycidyl (meth)acrylate so that the chlorine content in the glycidyl (meth)acrylate is 0.01 to 0.3% by mass; (2) polymerizing a monomer component containing an N-substituted maleimide monomer (a) and the purified glycidyl (meth)acrylate obtained in step (II-1) to obtain a base polymer; and (3) reacting the base polymer with an unsaturated carboxylic acid monomer (b) to obtain an N-substituted maleimide polymer having a double bond in its side chain. The purified glycidyl (meth)acrylate obtained in step (II-1) is the glycidyl (meth)acrylate with a chlorine content adjusted to 0.01 to 0.3% by mass.

[0095] <Process (II-4)> The production method (II) preferably further comprises, after the step (II-3), a step (II-4) of reacting the N-substituted maleimide polymer having a double bond in its side chain with a polybasic acid or a polybasic acid anhydride. By carrying out the step (II-4), a carboxyl group can be generated by reacting the hydroxyl group generated by the reaction of the epoxy group with the carboxyl group in the step (II-3) with the polybasic acid or the polybasic acid anhydride, and the acid value of the N-substituted maleimide polymer can be adjusted to an appropriate range.

[0096] Examples of the polybasic acid or polybasic acid anhydride include polybasic acids such as succinic acid, maleic acid, phthalic acid, and tetrahydrophthalic acid; dibasic acid anhydrides such as succinic anhydride (also known as succinic anhydride), maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, and itaconic anhydride; trimellitic anhydride; etc. Among these, succinic acid and polybasic acid anhydrides are preferred, and from the viewpoints of high reactivity and ease of industrial availability, succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride are more preferred.

[0097] The reaction temperature in the reaction with the polybasic acid or polybasic anhydride is not particularly limited as long as the reaction proceeds at the temperature, but may be, for example, 0 to 200°C, preferably 20 to 150°C, and more preferably 30 to 120°C. The reaction time is not particularly limited, but may be, for example, 1 to 12 hours, preferably 2 to 12 hours, and more preferably 2 to 8 hours.

[0098] The amount of the polybasic acid or polybasic anhydride used is not particularly limited, and may be set so that the acid value of the resulting N-substituted maleimide polymer falls within the desired range.

[0099] The above-mentioned production method (II) may include other steps in addition to the above-mentioned steps (II-1), (II-2), (II-3), and (II-4). Examples of the other steps include an aging step, a neutralization step, a step of deactivating the polymerization initiator or the chain transfer agent, a dilution step, a drying step, a concentration step, and a purification step. These steps can be carried out by known methods.

[0100] The N-substituted maleimide polymer obtained by the above production method (I) or (II) preferably has a residual chlorine content of 100 to 2000 ppm relative to the total amount of the N-substituted maleimide monomer (a) and glycidyl (meth)acrylate used. The total amount used is the total mass of the monomers used during polymerization. In order to further suppress thermal discoloration during curing, the residual chlorine content in the polymer is more preferably 1800 ppm or less, even more preferably 1500 ppm or less, and particularly preferably 1000 ppm or less, based on the total amount of the N-substituted maleimide monomer (a) and glycidyl (meth)acrylate used. In order to facilitate industrial production of the raw material glycidyl (meth)acrylate, the lower limit of the residual chlorine content is more preferably 200 ppm or more, even more preferably 300 ppm or more, based on the total amount of the N-substituted maleimide monomer (a) and glycidyl (meth)acrylate used. The amount of residual chlorine in the polymer can be determined by measuring the amount of residual chlorine in the polymer using the same method as the method for measuring the amount of chlorine contained in glycidyl (meth)acrylate described above, and dividing the resulting value by the total amount (mass) of the N-substituted maleimide monomer (a) and glycidyl (meth)acrylate used as raw materials for the polymer. In the present invention, glycidyl (meth)acrylate adjusted to a predetermined range of chlorine content is used, but unadjusted glycidyl (meth)acrylate may also be used in combination. When not only the adjusted glycidyl (meth)acrylate but also unadjusted glycidyl (meth)acrylate is used, the amount of glycidyl (meth)acrylate used refers to the total amount of glycidyl (meth)acrylate used, including the unadjusted glycidyl (meth)acrylate.

[0101] Furthermore, the N-substituted maleimide polymer obtained by the above production method (I) or (II) preferably has a residual epichlorohydrin content of 0.001 to 5 ppm in the polymer. When the residual epichlorohydrin content is within the above range, the N-substituted maleimide polymer is excellent in safety during production and use, and thermal coloration during curing can be further suppressed. Glycidyl (meth)acrylate is usually produced by reacting (meth)acrylic acid with epichlorohydrin. Therefore, glycidyl (meth)acrylate contains residual chlorine as an impurity, as well as residual epichlorohydrin. Epichlorohydrin is known to be highly reactive and harmful to the human body. The production method of the present invention can reduce not only residual chlorine but also residual epichlorohydrin, thereby producing an N-substituted maleimide polymer that not only inhibits thermal discoloration but also has excellent safety. The amount of residual epichlorohydrin is more preferably 1 ppm or less, and even more preferably 0.5 ppm or less. The lower limit of the amount of residual epichlorohydrin is more preferably 0.01 ppm or more, from the viewpoint of industrial advantage in that the equipment required for purifying glycidyl (meth)acrylate is not excessively large. The amount of residual epichlorohydrin in the polymer can be determined by measurement using a GC-MS method, specifically, by the method described in the examples below.

[0102] In this way, the N-substituted maleimide polymer obtained by the production method (I) or (II) of the present invention has a residual chlorine content within a predetermined range, and therefore thermal discoloration during curing can be significantly suppressed. Such an N-substituted maleimide polymer obtained by the production method (I) or (II) also constitutes one aspect of the present invention. A preferred embodiment of the N-substituted maleimide polymer obtained by the above production method (I) or (II) will be described below.

[0103] 2. N-substituted maleimide polymers The present invention also relates to an N-substituted maleimide polymer having a structural unit (A) derived from an N-substituted maleimide monomer and a structural unit (B) represented by the following general formula (B1), (B2), or (B3), wherein the structural unit (B) contains a structure derived from glycidyl (meth)acrylate, and the amount of residual chlorine in the N-substituted maleimide polymer is 100 to 2000 ppm relative to the total mass of the N-substituted maleimide monomer that provides the structural unit (A) and the glycidyl (meth)acrylate that provides the structural unit (B), which are raw materials for the polymer.

[0104] [ka]

[0105] (In general formula (B1), R 1 and R 3 are the same or different and represent a hydrogen atom or a methyl group. 2 represents a divalent linking group. a is 0 or 1. In general formula (B2), R 4 represents a hydrogen atom or a methyl group. 5 represents an ethylenically unsaturated bond-containing group. In general formula (B3), R 6 represents a hydrogen atom or a methyl group. 7 represents an ethylenically unsaturated bond-containing group. X represents a divalent hydrocarbon group.

[0106] The N-substituted maleimide polymer of the present invention has a residual chlorine content of 100 to 2000 ppm relative to the total mass of the N-substituted maleimide monomer that provides the structural unit (A) and the glycidyl (meth)acrylate that provides the structural unit (B), which are raw materials for the polymer, and therefore thermal coloration of the polymer during curing can be suppressed. The residual chlorine content is preferably 1800 ppm or less, more preferably 1500 ppm or less, and even more preferably 1200 ppm or less, relative to the total mass, in order to further suppress thermal discoloration during curing. The amount of residual chlorine in the polymer can be determined by measuring it in the same manner as the method for determining the amount of residual chlorine in a polymer described above in "1. Method for producing N-substituted maleimide polymer."

[0107] The N-substituted maleimide monomer that provides the structural unit (A) is a polymer raw material that can be polymerized to obtain a polymer having the structural unit (A) by polymerizing a monomer component containing the N-substituted maleimide monomer. Glycidyl (meth)acrylate, which provides the structural unit (B), does not directly provide the structural unit (B) through polymerization, but is a polymer raw material that can form the structural unit (B) by reacting with functional groups derived from other monomer components, etc. That is, as will be described later, the structural unit (B) has a structure derived from glycidyl (meth)acrylate.

[0108] The N-substituted maleimide polymer has a structural unit (A) derived from an N-substituted maleimide monomer and a structural unit (B) represented by the general formula (B1), (B2), or (B3), and the structural unit (B) has a structure derived from glycidyl (meth)acrylate.

[0109] The N-substituted maleimide polymer having the structural unit derived from the N-substituted maleimide monomer and the structural unit represented by the general formula (B1) can be obtained by the above-mentioned production method (I). The N-substituted maleimide polymer having the structural unit derived from the N-substituted maleimide monomer and the structural unit represented by the general formula (B2) can be obtained by the above-mentioned production method (II), and preferably by the methods of steps (II-1) to (II-3). The N-substituted maleimide polymer having the structural unit derived from the N-substituted maleimide monomer and the structural unit represented by the general formula (B3) can be obtained by the above-mentioned production method (II), and preferably by the methods of steps (II-1) to (II-4).

[0110] The N-substituted maleimide polymer may have, as the structural unit (B), only one type of structural unit represented by general formula (B1), general formula (B2), or general formula (B3), or may have two or more types of structural units.

[0111] Preferred examples of the N-substituted maleimide monomer include the same N-substituted maleimide monomer (a) as described above in "1. Method for producing N-substituted maleimide polymer." Furthermore, one preferred embodiment of the present invention is one having two types of structural units derived from N-substituted maleimide monomers, that is, a structural unit derived from N-benzylmaleimide and a structural unit derived from N-phenylmaleimide.

[0112] In the above general formula (B1), R 1 and R 3 are the same or different and represent a hydrogen atom or a methyl group. R 2 represents a divalent linking group. Examples of the divalent linking group include an alkylene group, an alkenylene group, a cycloalkylene group, a cycloalkenylene group, an arylene group, a heteroarylene group, -O-, -CO-, -(CO)O-, -NH-, -SO2-, and combinations thereof. The divalent linking group preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 6 carbon atoms. R 2Preferred examples of the N-substituted maleimide polymer include residues of the unsaturated carboxylic acid monomer (b) described above in "1. Method for producing N-substituted maleimide polymer" excluding the polymerizable double bond group and the carboxyl group or the carboxylic acid anhydride group, and specific preferred examples thereof include -(CO)O-CH=CH- and the like. Examples of the polymerizable double bond group include a vinyl group, a (meth)acryloyl group, an allyl group, and a methallyl group. a is 0 or 1, but is preferably 0 in terms of reactivity and industrial availability.

[0113] In the general formula (B2) above, R 4 represents a hydrogen atom or a methyl group. R 5 represents an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include groups containing a polymerizable double bond, such as a (meth)acryloyl group, a vinyl group, an allyl group, and a methallyl group. Preferred examples include residues of the unsaturated carboxylic acid monomer (b) described above in "1. Method for producing an N-substituted maleimide polymer" excluding the carboxyl group or the carboxylic acid anhydride group. R 5 Specific examples of the alkyl group include -(CH2) m Examples include -O(CO)-CH=CH2 (m is an integer of 1 to 6), -CH=CH2, and -C(CH3)=CH2, and among these, -CH=CH2 and -C(CH3)=CH2 are preferred.

[0114] In the above general formula (B3), R 6 represents a hydrogen atom or a methyl group. R 7 represents an ethylenically unsaturated bond-containing group. The ethylenically unsaturated bond-containing group includes the above R 5 Preferred examples of the ethylenically unsaturated group include the same groups as those of the above.

[0115] X represents a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include a divalent linear or cyclic aliphatic hydrocarbon group and a divalent aromatic hydrocarbon group. Examples of the divalent chain aliphatic hydrocarbon group include a methylene group, an ethylene group, a trimethylene group, a propylene group, an ethylidene group, a propylidene group, an isopropylidene group, a vinylene group, a propenylene group, and a vinylidene group, and preferably a divalent chain aliphatic hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms. Examples of the divalent cyclic aliphatic hydrocarbon group include a 1,2-cyclopentylene group, a 1,2-cyclohexylene group, a 1,4-cyclohexylene group, a 1,2-cyclohexenylene group, a 1,4-cyclohexenylene group, a cyclopentylidene group, and a cyclohexylidene group, preferably a divalent cyclic aliphatic hydrocarbon group having 4 to 12 carbon atoms, more preferably 4 to 8 carbon atoms. Examples of the divalent aromatic hydrocarbon group include a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a benzylidene group, and a cinnamylidene group, and preferably a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms. The hydrocarbon group may have a substituent, such as an alkyl group, an aryl group, a hydroxyl group, a halogen atom, a carboxyl group, an alkoxy group, or an aryloxy group.

[0116] Among these, X is preferably a residue of the polybasic acid or polybasic acid anhydride described above in "1. Method for producing N-substituted maleimide polymer" other than a carboxyl group or a carboxylic acid anhydride group. Specific examples of X include -(CH)-, -CH=CH-, -CH-C(=CH)H-, a phenylene group, a cyclohexylene group, and a cyclohexenylene group.

[0117] In the above general formulae (B1), (B2) and (B3), examples of the structure derived from the (meth)acrylic chain glycidyl are as follows.

[0118] [ka]

[0119] The N-substituted maleimide polymer may have a structural unit (C) other than the structural units (A) and (B). Examples of the structural unit (C) include the structural unit derived from the monomer (c) described in "1. Method for producing an N-substituted maleimide polymer." The N-substituted maleimide polymer may further have a structural unit represented by the general formula (B1), (B2), or (B3) above that is not derived from glycidyl (meth)acrylate. This structural unit is included in the other structural unit (C).

[0120] The content ratio of each of the structural units (A), (B), and (C) can be appropriately set depending on the purpose and application of the N-substituted maleimide polymer. For example, the content ratio of the structural unit (A) is preferably 0.5 to 50 mass%, more preferably 1 to 30 mass%, and even more preferably 3 to 20 mass%, relative to 100 mass% of all structural units. The content of the structural unit (B) is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 20 to 40% by mass. The content of the structural unit (C) is preferably 10 to 90 mass %, more preferably 20 to 80 mass %, and even more preferably 25 to 70 mass %.

[0121] The weight-average molecular weight of the N-substituted maleimide polymer can be appropriately set depending on the purpose and application of the polymer, but is preferably 2,000 to 1,000,000, more preferably 3,000 or more, and even more preferably 5,000 or more. Also, it is more preferably 50,000 or less, and even more preferably 30,000 or less. The weight average molecular weight can be determined by gel permeation chromatography (GPC), specifically by the method described in the examples below.

[0122] The acid value of the N-substituted maleimide polymer is preferably 20 to 200 mgKOH / g, more preferably 30 mgKOH / g or more, even more preferably 40 mgKOH / g or more, more preferably 180 mgKOH / g or less, even more preferably 160 mgKOH / g or less. The acid value can be determined by neutralization titration using a KOH solution.

[0123] The N-substituted maleimide polymer has a double bond in a side chain. The double bond equivalent of the N-substituted maleimide polymer is preferably 300 to 30,000 g / equivalent. In terms of excellent storage stability of the polymer, the double bond equivalent is more preferably 400 g / equivalent or more, and even more preferably 420 g / equivalent or more. In terms of reactivity to light and heat, the double bond equivalent is more preferably 3,000 g / equivalent or less, and even more preferably 2,000 g / equivalent or less.

[0124] The double bond equivalent is the mass of the solid content of the polymer solution per mole of double bonds in the N-substituted maleimide polymer. The double bond equivalent can be determined by dividing the mass (g) of the resin solid content of the polymer solution by the amount (mol) of double bonds in the polymer. It can also be measured using various analyses such as titration, elemental analysis, NMR, and IR, or differential scanning calorimetry. For example, it can be calculated by measuring the number of ethylenic double bonds contained per gram of polymer in accordance with the iodine value test method described in JIS K 0070:1992.

[0125] 3. Curable resin composition The above-mentioned N-substituted maleimide polymer can be further combined with a polymerizable compound to form a curable resin composition. Since the curable resin composition contains the N-substituted maleimide polymer, it can provide a cured product in which thermal coloration is suppressed. Furthermore, by further containing a polymerizable compound, it is possible to improve various physical properties such as the curability of the resin composition and the mechanical strength and solvent resistance of the cured product. Such a curable resin composition containing the above-mentioned N-substituted maleimide polymer and polymerizable compound also constitutes one aspect of the present invention. The curable resin composition of the present invention can also be suitably used as a photosensitive resin composition.

[0126] The content of the N-substituted maleimide polymer in the curable resin composition of the present invention is not particularly limited and can be set appropriately depending on the intended use, the blending of other components, and the like. For example, the content is preferably 5 to 90 mass%, more preferably 10 to 80 mass%, and even more preferably 15 to 70 mass%, relative to 100 mass% of the total solid content of the curable resin composition. The term "total amount of solids" refers to the total amount of components that form the cured product (components excluding solvents and the like that volatilize during the formation of the cured product).

[0127] <Polymerizable compound> Examples of the polymerizable compound include low molecular weight compounds 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.), and electron beams, and examples thereof include monofunctional compounds having one polymerizable unsaturated group in the molecule, and polyfunctional compounds having two or more polymerizable unsaturated groups.

[0128] Examples of the monofunctional compound include N-substituted maleimide monomers; (meth)acrylic acid esters; (meth)acrylamides; unsaturated monocarboxylic acids; unsaturated polycarboxylic acids; unsaturated monocarboxylic acids in which the unsaturated group and the carboxyl group are chain-extended; unsaturated acid anhydrides; aromatic vinyls; conjugated dienes; vinyl esters; vinyl ethers; N-vinyl compounds; unsaturated isocyanates; and the like. These include the same compounds as those listed as the monomer components of the N-substituted maleimide polymer. Monomers having an active methylene group or an active methine group can also be used.

[0129] Examples of the polyfunctional compound include the following compounds. 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, and bisphenol F alkylene oxide di(meth)acrylate;

[0130] Trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin 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, dipentaerythritol pentaacrylate succinic acid-modified product, pentaerythritol triacrylate succinic acid-modified product, dipentaerythritol pentaacrylate phthalic acid-modified product, pentaerythritol triacrylate phthalic acid-modified product,

[0131] [ka] a tri- or higher functional (meth)acrylate compound such as a modified product of dipentaerythritol hexaacrylate represented by the formula:

[0132] 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, and ethylene oxide-added dipentaerythritol hexavinyl ether;

[0133] vinyl ether group-containing (meth)acrylic acid esters such as 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, and 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate;

[0134] 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, and ethylene oxide-added dipentaerythritol hexaallyl ether;

[0135] Allyl group-containing (meth)acrylic acid esters such as allyl (meth)acrylate; polyfunctional (meth)acryloyl group-containing isocyanurates such as tri(acryloyloxyethyl)isocyanurate, tri(methacryloyloxyethyl)isocyanurate, alkylene oxide-added tri(acryloyloxyethyl)isocyanurate, and alkylene oxide-added tri(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, and xylylene diisocyanate with hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; polyfunctional aromatic vinyls such as divinylbenzene; and the like.

[0136] Among the above polymerizable compounds, it is preferable to use a polyfunctional polymerizable compound from the viewpoint of further enhancing the curability of the curable resin composition. The number of functionalities of the above polyfunctional polymerizable compound is preferably 3 or more, more preferably 4 or more. Moreover, the number of functionalities is preferably 10 or less, more preferably 8 or less. The molecular weight of the polymerizable compound is not particularly limited, but is preferably 2000 or less from the viewpoint of handling.

[0137] Among the polyfunctional polymerizable compounds, compounds having a (meth)acryloyl group, such as polyfunctional (meth)acrylate compounds, polyfunctional urethane (meth)acrylate compounds, and (meth)acryloyl group-containing isocyanurate compounds, are preferred from the viewpoints of reactivity, economy, availability, etc., and polyfunctional (meth)acrylate compounds are more preferred. By including a compound having a (meth)acryloyl group, the curable resin composition has better photosensitivity and curability, and a cured product with even higher hardness and transparency can be obtained. It is even more preferred to use a trifunctional or higher polyfunctional (meth)acrylate compound as the polyfunctional polymerizable compound. The polymerizable compounds may be used alone or in combination of two or more.

[0138] The content of the polymerizable compound in the curable resin composition of the present invention is not particularly limited and may be set as appropriate. For example, the content is preferably 5 to 95% by mass, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of the total solid content of the curable resin composition of the present invention, and more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0139] <Photopolymerization initiator> The curable resin composition of the present invention may further contain a photopolymerization initiator. By containing a photopolymerization initiator, the curability of the curable resin composition can be improved, and the performance of the obtained cured product can be improved. The photopolymerization initiator used in the present invention is preferably a radically polymerizable photopolymerization initiator, which generates polymerization-initiating radicals upon irradiation with active energy rays such as electromagnetic waves or electron beams.

[0140] The photopolymerization initiator is not particularly limited, and examples of known photopolymerization initiators that can be used include alkylphenone compounds, benzophenone compounds, benzoin compounds, thioxanthone compounds, halomethylated triazine compounds, halomethylated oxadiazole compounds, biimidazole compounds, oxime ester compounds, oxime ether compounds, titanocene compounds, benzoate ester compounds, and acridine compounds.

[0141] Among these, it is preferable to use alkylphenone compounds, oxime ester compounds, and oxime ether compounds as the photopolymerization initiator. Examples of such compounds include alkylphenone compounds such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one ("IRGACURE907", manufactured by BASF) and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 ("IRGACURE369", manufactured by BASF), 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime) ("OXE01", manufactured by BASF), and ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime). It is more preferable to use oxime ester compounds such as OXE02 (manufactured by BASF), 1,2-octanedione, 1-[4-(phenylthio)-,2-,(O-benzoyloxime)], ethanone (OXE03 (manufactured by BASF), and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime) (OXE04 (manufactured by BASF)). The photopolymerization initiators may be used alone or in combination of two or more.

[0142] The content of the photopolymerization initiator in the curable resin composition of the present invention 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 0.1 to 30 mass%, more preferably 0.5 to 25 mass%, and even more preferably 1 to 20 mass%, relative to 100 mass% of the total solid content of the curable resin composition of the present invention.

[0143] If necessary, one or more photosensitizers, photoradical polymerization accelerators, etc. may be used in combination. By using a photosensitizer and / or a photoradical polymerization accelerator in combination with the photopolymerization initiator, sensitivity and curability are further improved. Examples of the photosensitizer and photoradical polymerization accelerator include dye compounds such as xanthene dyes, coumarin dyes, 3-ketocoumarin compounds, and pyrromethene dyes; dialkylaminobenzene compounds such as ethyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-dimethylaminobenzoate; and mercaptan hydrogen donors such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, and 2-mercaptobenzimidazole. The amounts of these used can be appropriately determined using known methods.

[0144] <Other ingredients> The curable resin composition of the present invention may further contain other components as needed. Examples of such other components include solvents, colorants, dispersants, antioxidants, heat resistance improvers, leveling agents, development aids, quantum dot particles, inorganic fine particles such as zirconia or silica fine particles, silane-based, aluminum-based, or titanium-based coupling agents, fillers, thermosetting resins such as epoxy resins, phenolic resins, and polyvinylphenols, curing aids such as polyfunctional thiol compounds, plasticizers, polymerization inhibitors, UV absorbers, matting agents, antifoaming agents, antistatic agents, slip agents, surface modifiers, thixotropic agents, thixotropic aids, quinone diazide compounds, polyhydric phenol compounds, and acid generators. These may be used alone or in combination of two or more. These components may be appropriately selected from known components, and the amounts used may be appropriately determined.

[0145] <Method for preparing curable resin composition> The method for preparing the curable resin composition of the present invention is not particularly limited, and any known method may be used. For example, the above-mentioned components may be mixed and dispersed using various mixers or dispersers. The mixing and dispersion method is not particularly limited, and any known method may be used. Furthermore, other commonly performed steps may be further included. When the curable resin composition contains a colorant, a dispersion solution of the colorant may be prepared in advance, and then this dispersion solution may be mixed with the above-mentioned components. The dispersion solution of the colorant may be obtained by mixing the colorant, dispersant, and solvent, and dispersing the mixture using a known disperser such as a bead mill, roll mill, ball mill, jet mill, homogenizer, kneader, or blender. The obtained curable resin composition may be filtered, if necessary, using a filter or the like to remove fine particles from the composition.

[0146] The curable resin composition of the present invention can be, for example, applied to a substrate or molded into any shape depending on the composition, purpose, and application of the curable resin composition, and the coated or molded product can be cured by heating and / or irradiating with active energy rays to obtain a cured product. The above coating and molding methods can be carried out by known methods. The heating and irradiation with active energy rays can be carried out by appropriately selecting from known methods depending on the composition of the curable resin composition and the like. Examples of the active energy rays include ultraviolet rays and electron beams, with ultraviolet rays being preferred. The heating method is not particularly limited, but examples include heating at 180 to 280° C. for 5 to 120 minutes, preferably at 210 to 250° C. for 10 to 60 minutes.

[0147] 4.Applications The N-substituted maleimide polymer of the present invention and the curable resin composition containing the same can provide a cured product in which thermal discoloration is suppressed, and therefore the N-substituted maleimide polymer and the curable resin composition of the present invention can be suitably used in applications in which suppression of thermal discoloration is desired. Specific examples of the above-mentioned applications include color filters, black matrices, photospacers, black column spacers, inks, printing plates, printed wiring boards, semiconductor elements, photoresists, insulating films and other optical components used in liquid crystal, organic electroluminescence, quantum dot and micro LED liquid crystal displays, solid-state imaging elements, touch panel display devices and the like, as well as various applications such as electrical and electronic components; automotive parts; and paints. [Example]

[0148] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass." The methods for measuring various physical properties are as follows.

[0149] <Residual chlorine amount> The obtained N-substituted maleimide polymer solution was diluted 100 times with THF to prepare a measurement sample, which was measured under the following conditions to determine the amount of residual chlorine in the N-substituted maleimide polymer. Equipment: Agilent Technologies, ICP-MS Agilent 7700x Mass scan speed: 5000 amu / s The amount of residual chlorine relative to the total amount of N-substituted maleimide and glycidyl methacrylate was determined by dividing the value of the amount of residual chlorine measured above by the value of the total mass ratio of the N-substituted maleimide and glycidyl methacrylate used in the synthesis relative to the total amount of the N-substituted maleimide polymer solution.

[0150] <Weight average molecular weight> The weight average molecular weight of the N-substituted maleimide polymer was determined by gel permeation chromatography (GPC) under the following conditions. Equipment: Tosoh HLC-8320GPC Detector: RI Column: TSKgel SuperHZM-M Column temperature: 30℃ Flow rate: 0.6ml / min Calibration curve: Polystyrene Standards Eluent:THF

[0151] <Polymer concentration (mass%)> Approximately 1 g of the polymer solution was weighed into an aluminum cup, dissolved in approximately 3 g of acetone, and then air-dried at room temperature. The solution was then dried under vacuum at 160°C for 1.5 hours using a hot air dryer (manufactured by Espec Corporation, product name: PHH-101), cooled in a desiccator, and weighed. The solid content (% by mass) of the polymer solution was calculated from the mass loss.

[0152] <Acid value> 1.5 g of the polymer solution was precisely weighed and dissolved in a mixed solvent of 90 g of acetone and 10 g of water, and titrated with a 0.1 N KOH aqueous solution. The titration was performed using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of polymer (mg KOH / g) was calculated from the polymer concentration.

[0153] <Double bond equivalent> The iodine value was calculated by measuring the number of ethylenic double bonds contained in 1 g of polymer in accordance with the testing method for iodine value described in JIS K 0070:1992.

[0154] <Residual epichlorohydrin amount> The amount of epichlorohydrin contained in the N-substituted maleimide polymer solution was measured by GC-MS under the following conditions. Equipment: GC-MS: ThermoQuest PolarisQ Mass range: M / e 20-200 EI method Constant temperature chamber: 40℃ (0min) → 10℃ / min → 200℃ (0min) Flow rate: He 1.0ml / min Sample preparation: Dilute the polymer solution 5 times with methanol

[0155] <Heat resistance> (Preparation of Resin Composition Solution) A resin composition solution was obtained by mixing 10 parts of the N-substituted maleimide polymer solution, 10 parts of dipentaerythritol hexaacrylate (DPHA) as a radical polymerizable compound, 1 part of Irgacure 907 (manufactured by BASF) as a photopolymerization initiator, and 30 parts of PGMEA.

[0156] (b * (measurement of values) The obtained resin composition solution was applied using a spin coater (1H-D7, manufactured by Mikasa Co., Ltd.) in an amount of 0.4 to 1.2 mg / cm in terms of solid content. 2 The resin composition was uniformly coated onto a 5 cm square glass substrate (soda lime glass AS-2K, manufactured by Toshin Riko Co., Ltd.) so that the coating amount (solid content equivalent) was changed by changing the rotation speed of the spin coater, and two coated plates with different coating amounts were prepared. One of the two plates always had a coating amount of 0.6 mg / cm. 2 To achieve a larger value, the coating amount of the other sheet must be 0.6 mg / cm 2 It was made to be a smaller value. These coated plates were dried at 90°C for 3 minutes to obtain laminates in which coating films were formed on the glass substrates. 2 After the resin adhering to the edge of the glass substrate was removed, the resulting laminate was subjected to a heat treatment at 230°C for 30 minutes using a Perfect Oven incubator (manufactured by Espec Corporation) and then cooled to room temperature. After cooling, the coating film surface of the laminate was measured using a colorimeter ZE6000 (manufactured by Nippon Denshoku Industries Co., Ltd.), and the b after the heating test was * The coating weight (x) and b were calculated from the measurements of two coatings prepared as described above for each coating. * The approximate straight line (calibration curve) of the value (y) was calculated, and the coating amount was 0.6 mg / cm 2 In the case of b * The values ​​were used as the evaluation results of the heat resistance of each coating film.

[0157] Purification of glycidyl methacrylate (Preparation Example 1) Commercially available glycidyl methacrylate (manufactured by NOF Corporation) was washed with water in a decanter, and the oil was separated using a separatory funnel and dried and dehydrated using silica gel until the water content was 500 ppm or less. Next, using a glass vacuum distillation apparatus equipped with a 10-theoretical-plate rectification column equipped with packing, precision distillation was carried out at 64-66°C under a reduced pressure of 800 Pa, and 200 ppm of methoquinone was added as a polymerization inhibitor to obtain purified glycidyl methacrylate A. The amount of chlorine contained in the obtained purified glycidyl methacrylate A (purified product A) was measured and found to be 0.2% by mass. Furthermore, the amount of chlorine contained in glycidyl methacrylate (commercially available product) before purification was measured and found to be 0.5% by mass. The amount of chlorine contained in glycidyl methacrylate was measured in the same manner as in the measurement of the amount of residual chlorine in the N-substituted maleimide polymer described above.

[0158] (Preparation Example 2) The purified glycidyl methacrylate A obtained in Preparation Example 1 was washed with water again in a decanter, and the oil was separated using a separatory funnel. The oil was dehydrated and dried using silica gel, and then subjected to precision distillation in the same manner as in Preparation Example 1. 200 ppm of methoquinone was added to obtain purified glycidyl methacrylate B. The amount of chlorine contained in the obtained purified glycidyl methacrylate B (purified product B) was measured and found to be 0.1% by mass.

[0159] Example 1 A 2 L separable flask was charged with 347.9 g of propylene glycol monomethyl ether acetate (PGMEA) and 156.8 g of propylene glycol (PGM), and the atmosphere was replaced with nitrogen and the temperature was raised to 90°C. On the other hand, 67.0 g of N-benzylmaleimide (BzMI), 163.48 g of cyclohexyl methacrylate (CHMA), 3.35 g of methyl methacrylate (MMA), 101.17 g of methacrylic acid (MAA), 70.3 g of PGMEA, 20.2 g of PGM, 6.7 g of a polymerization initiator (Perbutyl (registered trademark) O, manufactured by NOF Corporation), and 6.7 g of a chain transfer agent (n-dodecyl mercaptan) were charged into a dropping tank, and the mixture was mixed and stirred to dissolve the BzMI. The mixture was continuously added dropwise from the dropping tank to the reaction tank at 90°C for 3 hours, and then maintained at 90°C for an additional 30 minutes. The temperature was then raised to 115°C, and the reaction was carried out for 1.5 hours. After the reaction, the mixture was cooled to room temperature, and a base polymer solution was obtained. To the resulting base polymer solution, 55.32 g of purified glycidyl methacrylate A (purified product A) obtained in Preparation Example 1, 1.2 g of triethylamine, and 0.6 g of polymerization inhibitor (ANTAGE (registered trademark) W400, manufactured by Kawaguchi Chemical Industry Co., Ltd.) were added, and the temperature was raised to 115°C while bubbling oxygen / nitrogen mixed gas adjusted to an oxygen concentration of 7% at 20 ml / min, and the reaction was carried out for 8 hours. Thereafter, the mixture was cooled to room temperature, and N-substituted maleimide polymer solution 1 (1000.72 g) was obtained. The total amount of BzMI and glycidyl methacrylate (GMA) used was 122.32 g, while the total liquid volume of polymer solution 1 was 1000.72 g, so the ratio of the total amount of BzMI and glycidyl methacrylate used to the total liquid volume was 12.22%.

[0160] The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 1 were measured using the methods described above. The residual chlorine content was 100 ppm relative to the polymer solution. Therefore, the residual chlorine content relative to the total amount of BzMI and GMA used was calculated to be 100 / 12.22% = 820 ppm. Heat resistance was also evaluated using the method described above. The results are shown in Table 1.

[0161] Example 2 An N-substituted maleimide polymer solution 2 was obtained in the same manner as in Example 1, except that N-cyclohexylmaleimide was used instead of N-benzylmaleimide. The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 2 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0162] Example 3 The same operation as in Example 1 was carried out, except that purified glycidyl methacrylate B (purified product B) obtained in Preparation Example 2 was used instead of purified glycidyl methacrylate A (purified product A), to obtain N-substituted maleimide-containing resin solution 3. The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 3 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0163] Example 4 A 2 L separable flask was charged with 312.8 g of propylene glycol monomethyl ether acetate (PGMEA) and 83.2 g of propylene glycol (PGM), and the atmosphere was replaced with nitrogen and the temperature was raised to 90°C. On the other hand, 36.0 g of N-benzylmaleimide (BzMI), 95.04 g of benzyl methacrylate (BzMA), 108.96 g of acrylic acid (AA), 115.2 g of PGMEA, 28.8 g of PGM, 4.8 g of a polymerization initiator (Perbutyl (registered trademark) O, manufactured by NOF Corp.), and 0.72 g of a chain transfer agent (n-dodecyl mercaptan) were charged into a dropping tank, and the mixture was mixed and stirred to dissolve the BzMI. The solution was continuously added dropwise from the dropping tank to the reaction tank at 90°C for 3 hours, and then the temperature was maintained at 90°C for another 30 minutes, after which the temperature was raised to 115°C and the reaction was carried out for 1.5 hours. After cooling to room temperature, 165.2 g of purified glycidyl methacrylate B (purified product B) obtained in Preparation Example 2, 1.2 g of dimethylbenzylamine, and 0.6 g of a polymerization inhibitor (ANTAGE (registered trademark) W400, manufactured by Kawaguchi Chemical Industry Co., Ltd.) were added, and the temperature was raised to 110°C while bubbling oxygen / nitrogen mixed gas adjusted to an oxygen concentration of 7% at 20 ml / min, and the reaction was carried out for 12 hours. Thereafter, the mixture was cooled to room temperature, and an N-substituted maleimide polymer solution 4 was obtained. The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 4 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0164] Example 5 A 2 L separable flask was charged with 522.0 g of propylene glycol monomethyl ether acetate (PGMEA), and the atmosphere was replaced with nitrogen and heated to 90°C. On the other hand, 43.6 g of N-benzylmaleimide (BzMI), 66.9 g of benzyl methacrylate (BzMA), 123.8 g of purified glycidyl methacrylate (purified product B) obtained in Preparation Example 2, 100.0 g of PGMEA, 4.8 g of a polymerization initiator (t-butylperoxy-2-ethylhexanoate), and 2.72 g of a chain transfer agent (n-dodecyl mercaptan) were charged into a dropping tank, and the mixture was mixed and stirred to dissolve the BzMI. The solution was continuously added dropwise from the dropping tank to the reaction tank at 90°C for 3 hours, and then the temperature was maintained at 90°C for another 30 minutes, after which the temperature was raised to 115°C and the reaction was carried out for 1.5 hours. After cooling to room temperature, 62.8 g of acrylic acid (AA), 1.2 g of dimethylbenzylamine, and 0.6 g of a polymerization inhibitor (ANTAGE (registered trademark) W400, manufactured by Kawaguchi Chemical Industry Co., Ltd.) were added, and the temperature was raised to 110°C while bubbling oxygen / nitrogen mixed gas adjusted to an oxygen concentration of 7% at 20 ml / min, and the reaction was carried out for 12 hours. After that, the mixture was cooled to room temperature, and 81.7 g of tetrahydrophthalic anhydride (THPA) was added. After reacting at 100° C. for 3 hours, the mixture was cooled to room temperature to obtain an N-substituted maleimide polymer solution 5. The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 5 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0165] Example 6 N-substituted maleimide polymer solution 6 was obtained by carrying out the same operation as in Example 1, except that the amount of N-benzylmaleimide (BzMI) was changed to 6.7 g and the amount of cyclohexyl methacrylate (CHMA) was changed to 223.78 g. The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 6 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0166] Example 7 N-substituted maleimide polymer solution 7 was obtained by carrying out the same operation as in Example 3, except that the amount of N-benzylmaleimide (BzMI) was changed to 6.7 g and the amount of phenylmaleimide (PMI) was changed to 60.3 g. The weight-average molecular weight, polymer concentration, acid value, double bond equivalent, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 7 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0167] (Comparative Example 1) The same operation as in Example 1 was carried out, except that unpurified glycidyl methacrylate (commercially available product) was used instead of purified glycidyl methacrylate A, to obtain N-substituted maleimide polymer solution 8. The weight-average molecular weight, acid value, double bond equivalent, polymer concentration, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 8 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0168] (Comparative Example 2) The same operation as in Example 4 was carried out, except that unpurified glycidyl methacrylate (commercially available product) was used instead of purified glycidyl methacrylate B, to obtain N-substituted maleimide polymer solution 9. The weight-average molecular weight, acid value, double bond equivalent, polymer concentration, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 9 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0169] (Comparative Example 3) The same procedure as in Example 7 was carried out, except that unpurified glycidyl methacrylate (commercially available product) was used instead of purified glycidyl methacrylate B, to obtain an N-substituted maleimide polymer solution 10. The weight-average molecular weight, acid value, double bond equivalent, polymer concentration, residual chlorine content, and epichlorohydrin content of the resulting N-substituted maleimide polymer solution 10 were measured by the methods described above. Heat resistance was also evaluated by the same method. The results are shown in Table 1.

[0170] [Table 1]

[0171] The descriptions in Table 1 represent the following: BzMI: N-benzylmaleimide CHMI: N-cyclohexylmaleimide PMI: Phenylmaleimide CHMA: Cyclohexyl methacrylate MMA: methyl methacrylate BzMA: benzyl methacrylate MAA: methacrylic acid AA: acrylic acid GMA: Glycidyl methacrylate THPA: Tetrahydrophthalic anhydride Refined product A: Refined glycidyl methacrylate A Refined product B: Refined glycidyl methacrylate B Commercially available product: Unrefined glycidyl methacrylate

[0172] Table 1 shows that N-substituted maleimide polymers obtained using glycidyl (meth)acrylate adjusted to have a chlorine content of 0.01 to 0.3% by mass have excellent heat resistance and are significantly less likely to develop thermal discoloration during curing, compared to N-substituted maleimide polymers obtained using glycidyl (meth)acrylate with a chlorine content of more than 0.3% by mass.

Claims

1. a step (I-2) of polymerizing a monomer component containing an N-substituted maleimide monomer (a), an unsaturated carboxylic acid monomer (b), and a monomer (c) copolymerizable with the monomer (a) and the monomer (b) (excluding those containing glycerol methacrylate or N-vinylpyrrolidone) to obtain a base polymer; and and (I-3) reacting the base polymer with glycidyl (meth)acrylate, the chlorine content of which has been adjusted to 0.01 to 0.3% by mass, to obtain an N-substituted maleimide polymer having a double bond in the side chain. A method for producing an N-substituted maleimide polymer, comprising:

2. 2. The method for producing an N-substituted maleimide polymer according to claim 1, wherein the monomer (c) is at least one selected from the group consisting of hydroxyalkyl (meth)acrylates, (meth)acrylic acid esters, alicyclic (meth)acrylates, epoxy group-containing monomers (excluding glycidyl (meth)acrylate), vinyl ethers, aromatic vinyls, unsaturated isocyanates, α-(unsaturated alkoxyalkyl)acrylate monomers, and dialkyl-2,2′-(oxydimethylene)diacrylate monomers.

3. the content of the monomer (a) is 0.5% by mass or more and 50% by mass or less, based on 100% by mass of the total monomer components; the content of the monomer (b) is 5% by mass or more and 60% by mass or less, based on 100% by mass of the total monomer components; 3. The method for producing an N-substituted maleimide polymer according to claim 1, wherein the content of the monomer (c) is 10% by mass or more and 90% by mass or less, based on 100% by mass of the total monomer components.

4. The method for producing an N-substituted maleimide polymer according to any one of claims 1 to 3, further comprising, before the step (I-2), a step (I-1) of purifying the glycidyl (meth)acrylate so that the chlorine content in the glycidyl (meth)acrylate is 0.01 to 0.3 mass%.

5. 5. The method for producing an N-substituted maleimide polymer according to claim 1, wherein the N-substituted maleimide monomer (a) is at least one selected from the group consisting of N-benzylmaleimide and N-cyclohexylmaleimide.

6. The method for producing an N-substituted maleimide polymer according to any one of claims 1 to 5, wherein the amount of residual chlorine in the N-substituted maleimide polymer is 100 to 1800 ppm based on the total amount of the N-substituted maleimide monomer (a) and glycidyl (meth)acrylate used.

7. An N-substituted maleimide polymer having a structural unit (A) derived from an N-substituted maleimide monomer and a structural unit (B) represented by the following general formula (B1), (B2) or (B3): The structural unit (B) contains a structure derived from glycidyl (meth)acrylate, The amount of residual chlorine in the N-substituted maleimide polymer is 100 to 1800 ppm based on the total mass of the N-substituted maleimide monomer that provides the structural unit (A) and glycidyl (meth)acrylate that provides the structural unit (B), which are raw materials for the polymer. An N-substituted maleimide polymer (excluding those having a structural unit derived from glycerol methacrylate or a structural unit derived from N-vinylpyrrolidone), characterized by: 【Chemical 1】 (In general formula (B1), R １ and R ３ are the same or different and represent a hydrogen atom or a methyl group. ２ represents a divalent linking group. a is 0 or 1. In general formula (B2), R ４ represents a hydrogen atom or a methyl group. ５ represents an ethylenically unsaturated bond-containing group. In general formula (B3), R ６ represents a hydrogen atom or a methyl group. ７ represents an ethylenically unsaturated bond-containing group; and X represents a divalent hydrocarbon group.

8. 8. The N-substituted maleimide polymer according to claim 7, wherein the chlorine content of the glycidyl (meth)acrylate is 0.01 to 0.3% by mass.

9. 9. The N-substituted maleimide polymer according to claim 7, wherein the N-substituted maleimide polymer has an acid value of 20 to 200 mgKOH / g.

10. 10. The N-substituted maleimide polymer according to claim 7, wherein the N-substituted maleimide polymer has a double bond equivalent of 300 to 3000 g / equivalent.

11. A curable resin composition comprising the N-substituted maleimide polymer according to any one of claims 7 to 10 and a polymerizable compound.

12. a step of mixing the N-substituted maleimide polymer obtained by the method for producing an N-substituted maleimide polymer according to any one of claims 1 to 6 with a polymerizable compound. A method for producing a curable resin composition comprising the steps of:

Images