TW202411281A - Copolymer, curable resin composition, and cured product - Google Patents

Abstract

The present invention provides a copolymer that has excellent curability, production stability, and storage stability, and can impart excellent solvent resistance to a cured product. The copolymer comprises a structural unit (A) derived from a compound (a) represented by the following formula (1), (In the formula, R ^1arepresents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2arepresents a divalent organic group. X ^arepresents a heteroatom.) a structural unit (B) derived from an epoxy group-containing polymerizable unsaturated compound (b), and a structural unit (C) derived from an addition reaction product of the compound (a) represented by the above formula (1) and an epoxy group-containing polymerizable unsaturated compound (c), the copolymer has a carboxyl group derived from the compound (a) represented by the above formula (1), an epoxy group derived from the epoxy group-containing polymerizable unsaturated compound (b), and a polymerizable unsaturated group derived from the epoxy group-containing polymerizable unsaturated compound (c).

Description

Copolymer, curable resin composition and cured product

The present invention relates to a copolymer, a curable resin composition and a cured product.

In the field of manufacturing various electronic devices represented by VLSI (very large scale integration) that require sub-micron-level micro-processing, higher density and high integration of devices are required. Therefore, the demand for photolithography technology as a method of forming fine patterns is getting higher and higher. On the other hand, in electronic parts such as liquid crystal display elements, integrated circuit elements, solid-state imaging elements, etc., protective films are provided to prevent their degradation and damage, interlayer insulating films for insulating wiring in a layered configuration, planarizing films for flattening the surface of the element, and insulating films for maintaining electrical insulation.

Liquid crystal display elements with interlayer insulating films, such as TFT-type liquid crystal display elements, are manufactured in the following manner: a polarizing plate is set on a glass substrate, a transparent conductive circuit layer such as ITO (indium tin oxide) and a thin film transistor (TFT) are formed, and the back panel is coated with an interlayer insulating film. On the other hand, a polarizing plate is set on the glass plate, a black matrix layer and a filter layer pattern are formed as needed, and a transparent conductive circuit layer and an interlayer insulating film are formed in sequence to form an upper panel. The back panel and the upper panel are made to face each other via a spacer, and liquid crystal is sealed between the two panels.

As a method for forming fine patterns and for sensitizing a photosensitive resin composition (photoresist), a chemically enhanced photoresist that is useful as a photoacid generator for a photosensitive agent is known. For example, a resin composition containing a copolymer containing a structural unit having an epoxy group and a photoacid generator is used, and a proton acid is generated from the photoacid generator by exposure, causing the epoxy group to cleave and cause a crosslinking reaction. As a result, the copolymer is insoluble in the developer and a pattern is formed. In this way, compared with the previous photoresist whose photoreaction efficiency (reaction per photon) is less than 1, a leap in sensitivity is achieved. Most of the photoresists currently developed are chemically enhanced, which are used to develop high-sensitivity materials corresponding to the shortening of the exposure light source.

Insulating films such as interlayer insulating films provided in TFT-type liquid crystal display elements and integrated circuit elements require fine patterning (fine processing). As a material for forming the insulating film, a radiation-sensitive resin composition is generally used. Such a radiation-sensitive resin composition is required to have high radiation sensitivity in order to improve productivity. When the insulating film has low solvent resistance, the insulating film may swell, deform, and peel off from the substrate due to organic solvents, thereby causing major obstacles in the manufacture of liquid crystal display elements and integrated circuit elements. Therefore, excellent solvent resistance is required for the insulating film.

In response to such a demand, Patent Document 1 discloses a copolymer having a polymerizable unsaturated group in a side chain (a copolymer obtained by adding acrylic acid and tetrahydrophthalic anhydride to a copolymer containing glycidyl methacrylate).

In addition, Patent Document 2 discloses a copolymer obtained by adding a highly reactive epoxy-containing monomer to a copolymer of an epoxy-containing monomer having low reactivity with a carboxyl group (a mixture of 3,4-epoxytricyclo[5.2.1.0 ^2,6 ]dec-9-yl acrylate and 3,4-epoxytricyclo[5.2.1.0 ^2,6 ]dec-8-yl acrylate) and a carboxyl-containing monomer. Prior Art Document Patent Document

Patent document 1: Japanese Patent Publication No. 2006-11359 Patent document 2: International Publication No. 2008/139679

Invent the problem you want to solve

However, the copolymer disclosed in Patent Document 1 cannot be said to have sufficient curability. In addition, in order to improve the curability, it is necessary to increase the unsaturated groups of the copolymer, which will reduce the carboxyl groups, making it difficult to achieve a balance between curability and developability.

The copolymer of Patent Document 2 has excellent storage stability and solvent resistance because it contains an epoxy-containing monomer with low reactivity with a carboxyl group. However, it needs to be cured at a high temperature of 230°C or higher, and has problems such as poor curability such as residues being easily left during development. In addition, if the epoxy-containing monomer is changed to 3,4-epoxyhexylmethyl methacrylate with relatively high reactivity in order to improve curability, it tends to react with the epoxy-containing monomer used in the addition reaction, resulting in a decrease in production stability.

In this specification, "poor storage stability" means that the weight average molecular weight of the copolymer increases over time, and "excellent storage stability" means that the weight average molecular weight of the copolymer does not increase or is not likely to increase even if stored for a long time. In addition, "low production stability" means that a uniform copolymer cannot be obtained during the production of the copolymer and gelation occurs, and "high production stability" means that a uniform copolymer can be obtained during the production of the copolymer and gelation does not occur easily. In addition, whether the obtained copolymer is uniform can be evaluated using molecular weight distribution.

Therefore, the purpose of the present invention is to provide a copolymer which is excellent in curing property, manufacturing stability, and storage stability, and can impart excellent solvent resistance to the cured product. In addition, the purpose of the present invention is to provide a curable resin composition containing the above-mentioned copolymer and its cured product. Technical means to solve the problem

The inventors of the present invention have discovered that a copolymer containing specific structural units has excellent curing properties, manufacturing stability, and storage stability, and imparts excellent solvent resistance to the cured product, thereby completing the invention of the present invention.

That is, the present invention provides a copolymer comprising a copolymer derived from the following formula (1): (wherein, R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2a represents a divalent organic group. X ^a represents a heteroatom) A copolymer of a structural unit (A) of a compound (a) represented by the aforementioned formula; a structural unit (B) derived from a polymerizable unsaturated compound (b) containing an epoxy group; and a structural unit (C) derived from an addition reaction product of a compound (a) represented by the aforementioned formula (1) and a polymerizable unsaturated compound (c) containing an epoxy group, and having a carboxyl group derived from the compound (a) represented by the aforementioned formula (1); an epoxy group derived from the aforementioned polymerizable unsaturated compound (b) containing an epoxy group; and a polymerizable unsaturated group derived from the aforementioned polymerizable unsaturated compound (c) containing an epoxy group.

The epoxy group of the compound (b) is preferably an alicyclic epoxy group.

The epoxy group of the compound (b) is preferably a monocyclic or bicyclic alicyclic epoxy group.

In the aforementioned compound (c), the epoxy group is preferably bonded to an aliphatic hydrocarbon group.

In the aforementioned compound (a), R ^2a in formula (1) is preferably a divalent organic group containing an ester bond.

The copolymer of the present invention preferably further comprises a structural unit (D) derived from at least one compound selected from the group consisting of (d1) to (d4) below. (d1) Styrene which may be substituted by an alkyl group (d2) N-substituted cis-butylene diimide (d3) N-vinyl compound (d4) The following formula (4) [Chemical Formula 2] (wherein, R ^1d represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2d represents a monovalent organic group. X ^d represents a heteroatom) Unsaturated carboxylic acid derivative represented by

In addition, the present invention provides a curable resin composition containing the above copolymer.

The aforementioned curable resin composition preferably further contains a photopolymerization initiator.

The aforementioned curable resin composition preferably further contains a colored material.

In addition, the present invention provides a cured product of the curable resin composition.

The cured product of the curable resin composition is preferably a color filter.

In addition, the present invention provides a method for producing a copolymer, characterized in that: (wherein, R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms; R ^2a represents a divalent organic group; X ^a represents a heteroatom) and a polymerizable unsaturated compound containing an epoxy group (b) are copolymerized, and then the epoxy group of the polymerizable unsaturated compound containing an epoxy group (c) is added to a part of the carboxyl groups of the obtained copolymer. Effect of the invention

The copolymer of the present invention has excellent curability, manufacturing stability, and storage stability, and imparts excellent solvent resistance to the cured product. In addition, the curable resin composition containing the copolymer has excellent curability. Moreover, the cured product has excellent solvent resistance.

＜Copolymer＞

The copolymer of the present invention is characterized in that it comprises a copolymer derived from the following formula (1): [Chemical Formula 4] (wherein, R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2a represents a divalent organic group. X ^a represents a heteroatom) A copolymer of a structural unit (A) of a compound (a) represented by the aforementioned formula; a structural unit (B) derived from a polymerizable unsaturated compound (b) containing an epoxy group; and a structural unit (C) derived from an addition reaction product of a compound (a) represented by the aforementioned formula (1) and a polymerizable unsaturated compound (c) containing an epoxy group, and having a carboxyl group derived from the compound (a) represented by the aforementioned formula (1); an epoxy group derived from the aforementioned polymerizable unsaturated compound (b) containing an epoxy group; and a polymerizable unsaturated group derived from the aforementioned polymerizable unsaturated compound (c) containing an epoxy group.

The copolymer of the present invention can be obtained by copolymerizing compounds corresponding to the aforementioned structural units (A) to (C). In addition, the copolymer of the present invention can also be obtained by subjecting a copolymer comprising a structural unit (A) derived from the compound (a) represented by the aforementioned formula (1) and a structural unit (B) derived from an epoxy-containing polymerizable unsaturated compound (b) to an addition reaction with an epoxy-containing polymerizable unsaturated compound (c). At this time, the carboxyl group derived from the compound (a) represented by the aforementioned formula (1) in the aforementioned copolymer is added to the epoxy group of the epoxy-containing polymerizable unsaturated compound (c) to form the structural unit (C). Therefore, the structural unit (A) that has not undergone addition reaction with the polymerizable unsaturated compound (c) containing an epoxy group becomes a carboxyl group derived from the compound (a) represented by formula (1), and the structural unit (C) becomes a polymerizable unsaturated group derived from the polymerizable unsaturated compound (c) containing an epoxy group.

The copolymer of the present invention may further include a structural unit (D) derived from at least one compound selected from the group consisting of the aforementioned (d1) to (d4). That is, the copolymer of the present invention can be obtained by copolymerizing compounds corresponding to the aforementioned structural units (A) to (C) and, if necessary, a compound corresponding to the structural unit (D). In addition, it can also be obtained by subjecting a copolymer comprising the aforementioned structural unit (A), the aforementioned structural unit (B) and the aforementioned structural unit (D) to an addition reaction with the aforementioned compound (c). [Structural unit (A)]

The structural unit (A) is a structural unit derived from the compound (a) represented by the aforementioned formula (1), and can be introduced into the copolymer by, for example, copolymerizing the compound (a) represented by the aforementioned formula (1) with the aforementioned polymerizable unsaturated compound (b) containing an epoxy group. The compound (a) represented by the aforementioned formula (1) can be used alone or in combination of two or more. The copolymer of the present invention has excellent production stability and storage stability by having the aforementioned structural unit (A).

The copolymer of the present invention has excellent manufacturing stability and storage stability due to the aforementioned structural unit (A). The reason for this is explained below using a structural unit derived from (meth)acrylic acid instead of the structural unit (A) in the copolymer of the present invention as a comparative object. (Regarding manufacturing stability)

As an embodiment, the copolymer of the present invention is obtained by subjecting a copolymer comprising a structural unit (A) derived from a compound (a) represented by the aforementioned formula (1) and a structural unit (B) derived from an epoxy-containing polymerizable unsaturated compound (b) to an addition reaction with an epoxy-containing polymerizable unsaturated compound (c), thereby adding epoxy groups of the aforementioned compound (c) to a portion of the carboxyl groups of the aforementioned copolymer. It is believed that in the aforementioned addition reaction, the epoxy groups of the aforementioned copolymer react preferentially with the epoxy groups of the aforementioned compound (c), thereby obtaining an uneven copolymer and causing gelation (i.e., poor manufacturing stability).

In a copolymer having a structural unit derived from (meth)acrylic acid instead of structural unit (A), the acidity of the copolymer as a whole becomes relatively high, so the reactivity of the epoxy group derived from the aforementioned compound (b) possessed by the aforementioned copolymer and the epoxy group of the aforementioned compound (c) increases, and these groups react preferentially. On the other hand, the addition reaction between the carboxyl group derived from (meth)acrylic acid possessed by the aforementioned copolymer and the epoxy group of the aforementioned compound (c) is difficult to occur. As a result, the target uniform copolymer cannot be obtained, and gelation may occur. In contrast, in the copolymer of the present invention, due to the structure of compound (a) shown in formula (1), the acidity of the copolymer as a whole becomes moderately low, so the reactivity of the epoxy group derived from the aforementioned compound (b) possessed by the aforementioned copolymer becomes low. As a result, the reaction between the carboxyl group of the compound (a) represented by the aforementioned formula (1) and the epoxy group of the aforementioned compound (c) in the aforementioned copolymer is preferred, so it is easy to obtain the target uniform copolymer and it is not easy to produce gelation. As described above, it can be said that the manufacturing stability of the copolymer of the present invention is excellent. (Regarding storage stability)

The copolymer of the present invention comprises a structural unit (A) derived from the aforementioned compound (a) and a structural unit (B) derived from the aforementioned compound (b). When the reactivity of the carboxyl group derived from the aforementioned compound (a) and the epoxy group derived from the aforementioned compound (b) is high, these groups react within the molecule (within the copolymer), and thus the weight average molecular weight of the copolymer increases over time.

In a copolymer having a structural unit derived from (meth) acrylic acid instead of the structural unit (A), the acidity of the copolymer as a whole becomes relatively high, so the reactivity of the epoxy group derived from the compound (b) possessed by the copolymer increases, and the carboxyl group derived from (meth) acrylic acid and the epoxy group react with each other. As a result, the weight average molecular weight of the copolymer increases over time during the storage of the curable resin composition. In contrast, in the copolymer of the present invention, the acidity of the copolymer as a whole becomes moderately low due to the structure of the compound (a) represented by formula (1), so the reactivity of the epoxy group derived from the compound (b) becomes low. Therefore, the carboxyl group derived from the compound (a) and the epoxy group derived from the compound (b) are not easy to react, and the weight average molecular weight of the copolymer tends to be difficult to increase even if it is stored for a long time.

In formula (1), R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2a represents a divalent organic group. X ^a represents a heteroatom.

Examples of the alkyl group having 1 to 7 carbon atoms in R ^1a include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, dibutyl, pentyl, hexyl, and heptyl.

Examples of the divalent organic group in R ^2a include alkylene groups such as methylene, ethylene, propylene, trimethylene (preferably alkylene groups having 1 to 20 carbon atoms, more preferably alkylene groups having 1 to 12 carbon atoms, further preferably alkylene groups having 1 to 6 carbon atoms, and particularly preferably alkylene groups having 1 to 3 carbon atoms), alkenylene (preferably alkenylene groups having 2 to 20 carbon atoms, more preferably alkenylene groups having 2 to 12 carbon atoms, and further preferably alkenylene groups having 2 to 6 carbon atoms), cycloalkylene, arylene, and groups in which a plurality of these groups are linked directly or via a linking group. Examples of the aforementioned linking group include ether bonds, carbonyl groups, ester bonds, thioether bonds, and amide groups, and from the viewpoints of production stability and storage stability, ester bonds are preferred. Since the divalent organic group contains an ester bond, the acidity of the copolymer including the structural unit (A) is moderately lowered, and thus the production stability and storage stability tend to be improved.

The aforementioned divalent organic group is not particularly limited. From the viewpoint of the curability, manufacturing stability and storage stability of the copolymer, it is preferably a group formed by two alkylene groups (preferably an alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms) via a linking group bond, more preferably a group formed by the above two alkylene groups via an ester bond, and further preferably a -C ₂ H ₄ -O-(C=O)-C ₂ H ₄ - group (the bond extending to the left from the left C ₂ H ₄ group is bonded to X ^a , and the bond extending to the right from the right C ₂ H ₄ group is bonded to the carbon atom of the (C=O)-OH group).

The carbon number (total number) in the aforementioned divalent organic group is not particularly limited, and is preferably 1 to 15, more preferably 2 to 10, and further preferably 3 to 6. By making the carbon number (total number) in the aforementioned divalent organic group within the above range, the acidity of the carboxyl group derived from the compound (a) represented by formula (1) is appropriately lowered, and thus the curability, production stability and storage stability of the copolymer tend to be improved.

The impurity atom in ^Xa is not particularly limited, and examples thereof include a nitrogen atom, an oxygen atom and a sulfur atom, and preferably an oxygen atom.

The ratio of the structural unit (A) in the copolymer is not particularly limited. For example, relative to all the structural units constituting the copolymer, it is preferably 10 to 50 mol%, and its lower limit is more preferably 20 mol%, and its upper limit is more preferably 40 mol%. By making the ratio of the structural unit (A) above the above lower limit, there is a tendency for excellent developing properties. By making the ratio of the structural unit (A) below the above upper limit, overdevelopment can be suppressed, and thus there is a tendency for excellent solvent resistance. In addition, in the present invention, the ratio of the structural unit in the copolymer is based on the molar amount of the compound (monomer) used in the copolymer. For example, the ratio of the structural unit (A) in the copolymer refers to the ratio of the amount of the compound (a) shown in formula (1) used relative to the total amount of the compound used in the copolymer (100 mol%). Among them, the structural unit derived from the compound (a) represented by formula (1) to which the epoxy group of the polymerizable unsaturated compound (c) containing an epoxy group is added becomes the structural unit (C), which is not included in the structural unit (A). Therefore, the ratio of the structural unit (A) in the copolymer is calculated as the amount of the compound (a) represented by formula (1) used minus the amount of the polymerizable unsaturated compound (c) containing an epoxy group. [Structural unit (B)]

The structural unit (B) is a structural unit derived from the epoxy-containing polymerizable unsaturated compound (b), and can be introduced into the copolymer by, for example, copolymerizing the epoxy-containing polymerizable unsaturated compound (b) with the compound (a) represented by the above formula (1). The epoxy-containing polymerizable unsaturated compound (b) can be used alone or in combination of two or more.

The aforementioned compound (b) is not particularly limited as long as it is a compound containing an epoxide group and a polymerizable unsaturated group, and the epoxide group is preferably an alicyclic epoxide group. That is, the aforementioned compound (b) is preferably a compound containing an alicyclic epoxide group and a polymerizable unsaturated group (a polymerizable unsaturated compound containing an alicyclic epoxide group). In addition, the alicyclic ring in the alicyclic epoxide group may also have a substituent other than an epoxide group. In addition, in this specification, "alicyclic epoxide group" refers to an epoxide group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring. By making the aforementioned compound (b) a polymerizable unsaturated compound containing an alicyclic epoxide group, the manufacturing stability and curability of the copolymer of the present invention tend to be improved. This is considered to be because the alicyclic epoxy group in the aforementioned compound has a low reactivity and therefore does not easily react with the epoxy group derived from the epoxy-containing polymerizable unsaturated compound (c).

Examples of the alicyclic epoxy group include epoxycyclohexyl, 2,3-epoxybicyclo[2.2.1]heptyl, 2,3-epoxy-7-oxabicyclo[2.2.1]heptyl, 3,4-epoxytricyclo[5.2.1.0 ^2,6 ]decyl (3,4-epoxydicyclopentyl), and groups having substituents on one or more carbon atoms constituting these groups.

From the viewpoint of curability, manufacturing stability and storage stability of the copolymer, the epoxy group in the compound (b) is preferably a monocyclic or bicyclic (excluding the ring formed by the epoxy group) alicyclic epoxy group. In addition, the alicyclic epoxy group preferably has an epoxycyclohexyl skeleton. When the alicyclic epoxy group has an epoxycyclohexyl skeleton, the compound (b) is preferably bonded to the polymerizable unsaturated group via the carbon atom at the 3rd or 4th position of the skeleton.

Examples of the aforementioned polymerizable unsaturated compound containing an alicyclic epoxy group include compounds represented by the following formula (2). [Chemical Formula 5]

In formula (2), R ^1b represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2b represents an alkyl group having 1 to 7 carbon atoms, which is the same or different. X ^b represents a single bond or a divalent organic group. In addition, R ^2b represents a substituent on the cyclohexane ring shown in formula (2), which is not included in the substituents possessed by Y ^b . Y ^b represents an unbonded group (meaning that there is no group corresponding to Y ^b ), a methylene group or an ethylene group which may have an alkyl group having 1 to 3 carbon atoms as a substituent, an oxygen atom, or a sulfur atom which may be bonded to an oxygen atom. n represents an integer greater than 0 (preferably an integer from 0 to 7).

Examples of the alkyl group having 1 to 7 carbon atoms in R ^1b include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, dibutyl, pentyl, hexyl, heptyl, etc. From the viewpoint of copolymerizability and reactivity, R ^1b is preferably a hydrogen atom, methyl or ethyl.

Examples of the alkyl group having 1 to 7 carbon atoms in R ^2b include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, dibutyl, pentyl, hexyl, and heptyl. When n is 2 or more, n R ^2b groups may be the same or different. From the viewpoint of copolymerizability and reactivity, R ^2b is preferably methyl or ethyl.

Examples of the divalent organic group in ^Xb include alkylene groups such as methylene, ethylene, propylene, and trimethylene (preferably alkylene groups having 1 to 20 carbon atoms, more preferably alkylene groups having 1 to 12 carbon atoms, further preferably alkylene groups having 1 to 6 carbon atoms, and particularly preferably alkylene groups having 1 to 3 carbon atoms), alkenylene groups (preferably alkenylene groups having 2 to 20 carbon atoms, more preferably alkenylene groups having 2 to 12 carbon atoms, and further preferably alkenylene groups having 2 to 6 carbon atoms), cycloalkylene groups, arylene groups, and groups in which a plurality of these groups are linked directly or via a linking group. Examples of the aforementioned linking group include ether bonds, carbonyl groups, ester bonds, thioether bonds, and amide groups.

X ^b is preferably bonded to the carbon atom at the 3-position or 4-position of the epoxycyclohexyl skeleton represented by formula (2).

The methylene group or ethylene group which may have an alkyl group having 1 to 3 carbon atoms as a substituent of Y ^b is not particularly limited, but is preferably a methylene group or an ethylene group, and more preferably a methylene group.

Examples of the sulfur atom that can bond to an oxygen atom as ^Yb include a sulfur atom and a sulfonyl group.

As the compound represented by the above formula (2), for example, a compound represented by the following formula (2') is exemplified. [Chemical Formula 6]

In formula (2'), R ^1b , R ^2b , X ^b , Y ^b and n are the same as those described in formula (2).

As specific examples of the compound represented by formula (2), the following compounds can be cited. [Chemical Formula 7] [Chemical formula 8]

The ratio of the structural unit (B) in the copolymer is not particularly limited, but is preferably 5 to 40 mol% relative to all the structural units constituting the copolymer, and its lower limit is more preferably 10 mol%, and further preferably 15 mol%. In addition, its upper limit is more preferably 35 mol%, and further preferably 30 mol%. By making the ratio of the structural unit (B) within the above range, the epoxy group contained in the copolymer becomes an amount suitable for curing, so it will cure even at a relatively low temperature, and the cross-linked structure of the cured product is dense, so it tends to have excellent solvent resistance. [Structural unit (C)]

The structural unit (C) is a structural unit derived from an addition reaction product of the compound (a) represented by the aforementioned formula (1) and the polymerizable unsaturated compound (c) containing an epoxy group. Specifically, it is a structural unit derived from a compound obtained by adding the epoxy group of the polymerizable unsaturated compound (c) containing an epoxy group to the carboxyl group of the compound (a) represented by the aforementioned formula (1).

The aforementioned epoxy-containing polymerizable unsaturated compound (c) is not particularly limited as long as it is a compound containing an epoxy group and a polymerizable unsaturated group, and may be the same as the aforementioned compound (b), but from the viewpoint of production stability, it is preferably different from the aforementioned epoxy-containing polymerizable unsaturated compound (b). In the epoxy-containing polymerizable unsaturated compound (c), the epoxy group is more preferably a group bonded to an aliphatic alkyl group (aliphatic epoxy group), and is particularly preferably a glycidyl group. The epoxy-containing polymerizable unsaturated compound (c) may be used alone or in combination of two or more.

Examples of the compound (c) include allyl glycidyl ether, glycidyl (meth)acrylate, 2-methyl glycidyl (meth)acrylate, 2-ethyl glycidyl (meth)acrylate, 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxypropyl (meth)acrylate, glycidyloxyphenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate glycidyl ether, and 4-hydroxybutyl (meth)acrylate glycidyl ether. Among them, glycidyl (meth)acrylate is preferred from the viewpoint of improved production stability and curability.

In the copolymer of the present invention, when the aforementioned compound (b) is a polymerizable unsaturated compound containing an alicyclic epoxy group, and the aforementioned compound (c) is a polymerizable unsaturated compound containing an aliphatic epoxy group (especially a polymerizable unsaturated compound containing a glycidyl group), not only the manufacturing stability and storage stability are excellent, but also the copolymer can be cured even at a relatively low temperature, and the cured product has excellent solvent resistance. The reasons for such a remarkable effect are considered to be: [1] the epoxide group of the polymerizable unsaturated compound containing an aliphatic epoxide group is highly reactive compared to the polymerizable unsaturated compound containing an aliphatic epoxide group, so that the carboxyl group derived from the compound (a) represented by formula (1) reacts preferentially with the epoxide group of the polymerizable unsaturated compound containing an aliphatic epoxide group, thereby achieving excellent production stability; [2] the epoxide group derived from the polymerizable unsaturated compound containing an aliphatic epoxide group [3] The copolymer has a low reactivity, and is not likely to react with the carboxyl group derived from the compound (a) represented by the formula (1), thereby having excellent stability. [3] The carboxyl group derived from the compound (a) represented by the formula (1), the epoxide group derived from the polymerizable unsaturated compound containing an alicyclic epoxide group, and the polymerizable unsaturated group derived from the polymerizable unsaturated compound containing an aliphatic epoxide group are present in a well-balanced manner, thereby contributing to improved curing properties.

The ratio (content) of the structural unit (C) in the copolymer is not particularly limited, for example, it is preferably 10 to 60 mol% relative to all the structural units constituting the copolymer, and its lower limit is more preferably 15 mol%. In addition, its upper limit is more preferably 50 mol%, and further preferably 35 mol%. By making the ratio of the structural unit (C) above the above lower limit, due to the presence of the polymerizable unsaturated group derived from the polymerizable unsaturated compound (c) containing an epoxy group, there is a tendency to cure even at a relatively low temperature. By making the ratio of the structural unit (C) below the above upper limit, the hydroxyl group contained in the copolymer becomes an appropriate amount, and therefore there is a tendency to have excellent solvent resistance especially for highly polar solvents. In addition, the copolymer becomes hydrophilic, and thus tends to have excellent developing properties (fast developing speed, less residue). In addition, in the present invention, the ratio of the structural unit (C) in the copolymer is calculated based on the molar amount of the polymerizable unsaturated epoxy group-containing compound (c) assuming that all the polymerizable unsaturated epoxy group-containing compound (c) used reacts with the carboxyl group of the compound (a) represented by formula (1). [Structural unit (D)]

The structural unit (D) is a structural unit derived from at least one compound selected from the group consisting of alkyl-substituted styrenes (d1), N-substituted cis-butylenediimide (d2), N-vinyl compounds (d3), and unsaturated carboxylic acid derivatives (d4) represented by the above formula (2). The structural unit (D) has the function of imparting hardness to the cured product (cured film), the function of smoothing the copolymerization reaction, the function of improving solubility in the solvent, the function of improving adhesion to the substrate, etc.

The structural unit (D) can be introduced into the copolymer by copolymerizing at least one compound selected from the group consisting of the aforementioned (d1) to (d4), the compound (a) represented by the aforementioned formula (1), and the aforementioned polymerizable unsaturated compound (b) containing an epoxy group. (Styrene (d1))

The alkyl group in the alkyl-substituted styrene (d1) is not particularly limited, and examples thereof include alkyl groups having 1 to 7 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, and hexyl. Among them, alkyl groups having 1 to 4 carbon atoms, such as methyl or ethyl, are preferred, and methyl is more preferred. The aforementioned alkyl group may be bonded to either the vinyl group or the benzene ring of styrene.

Representative examples of alkyl-substituted styrenes (d1) include styrene, α-methylstyrene, vinyltoluene (o-vinyltoluene, m-vinyltoluene, p-vinyltoluene), etc. Among them, styrene is preferred. Alkyl-substituted styrenes (d1) can be used alone or in combination of two or more. (N-substituted butylene diimide (d2))

As the N-substituted cis-butylenediimide (d2), for example, there can be mentioned the compound represented by the following formula (3). [Chemical Formula 9]

In formula (3), ^R1 represents a monovalent organic group.

Examples of the monovalent organic group include alkyl groups and heterocyclic groups. Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and hexyl (e.g., alkyl groups having 1 to 6 carbon atoms); cycloalkyl groups such as cyclopentyl, cyclohexyl, cyclooctyl, adamantyl, and norbornyl; aryl groups such as phenyl; aralkyl groups such as benzyl; groups formed by two or more bonds thereof. Examples of the heterocyclic group include 5- to 10-membered heterocycloalkyl groups and heteroaryl groups containing at least one hetero atom selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms.

The N-substituted cis-butenediamide (d2) is not particularly limited, and examples thereof include N-alkyl cis-butenediamides such as N-methyl cis-butenediamide, N-ethyl cis-butenediamide, and N-propyl cis-butenediamide; N-cyclopentyl cis-butenediamide, N-cyclohexyl cis-butenediamide; , N-cyclooctyl cis-butenediamide, N-adamantyl cis-butenediamide, N-norbornyl cis-butenediamide and other N-cycloalkyl cis-butenediamides; N-phenyl cis-butenediamide and other N-aryl cis-butenediamides; N-benzyl cis-butenediamide and other N-arylalkyl cis-butenediamides, etc. Among them, N-cyclohexyl cis-butenediamide is preferred. N-substituted cis-butenediamides (d2) can be used alone or in combination of two or more. (N-vinyl compound (d3))

The N-vinyl compound (d3) is not particularly limited, and examples thereof include N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropyl amide, N-vinyl-N-methyl acetamide, N-vinyl pyrrolidone, N-vinyl carbazole, N-vinyl piperidone, and N-vinyl caprolactam. The N-vinyl compound (d3) can be used alone or in combination of two or more. (Unsaturated carboxylic acid derivative (d4))

The unsaturated carboxylic acid derivative (d4) is represented by the following formula (4). [Chemical Formula 10]

In formula (4), R ^1d represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2d represents a monovalent organic group. X ^d represents a heteroatom.

Examples of the alkyl group having 1 to 7 carbon atoms in R ^1d include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, hexyl, etc. R ^1d is particularly preferably a hydrogen atom or a methyl group.

Examples of the monovalent organic group in R ^2d include carboxyl, alkyl, heteroalkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, and groups formed by linking two or more of these groups. In addition, the carbon atom in the monovalent organic group in R ^2d is bonded to X ^d .

Examples of the alkyl group include alkyl groups having 1 to 23 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, dibutyl, hexyl, octyl, decyl, dodecyl, isodecyl, lauryl, and stearyl.

Examples of the heteroalkyl group include -( ^R2d1 -O) ^pR2d2 (wherein ^R2d1 represents an alkylene group having 1 to 12 carbon atoms. ^R2d2 represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. p represents an integer greater than 1), ^-R2d3 - ^NR2d4R2d5 (wherein ^R2d3 represents an alkylene group having 1 to 12 carbon atoms. ^R2d4 and ^R2d5 represent, respectively, the same or different ^, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms).

Examples of the alkenyl group include alkenyl groups having 2 to 23 carbon atoms, such as allyl, 3-butenyl, and 5-hexenyl.

Examples of the cycloalkyl group include cycloalkyl groups having 3 to 12 carbon atoms, such as cyclopentyl, cyclohexyl, cyclooctyl, adamantyl, and norbornyl.

Examples of the heterocycloalkyl group include groups containing a cyclic ether structure (e.g., a cyclic ether containing group having three or more members) such as an oxycyclobutane ring, an oxycyclopentane ring, an oxycyclohexane ring, and an oxycycloheptane ring.

Examples of the aryl group include aryl groups having 6 to 12 carbon atoms, such as phenyl and naphthyl.

Examples of the impurity atom in X include a nitrogen atom, an oxygen atom, and a sulfur atom.

The unsaturated carboxylic acid derivative (d4) represented by the formula (4) is not particularly limited, and examples thereof include: (meth)acrylates having an alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate; (meth)acrylates having an alkylamino group such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-diisopropylaminoethyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. (meth)acrylates containing a hydroxyl group such as 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylates containing a heteroalkyl group such as methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, isooctyloxydiethylene glycol (meth)acrylate, phenoxytriethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, etc.; (meth)acrylates containing an alkenyl group such as allyl (meth)acrylate; cyclohexyl (meth)acrylate, 1-adamantyl (meth)acrylate, isooctyl (meth)acrylate, phenoxytriethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, etc.; esters, tricyclo[5,2,1,0 ^2,6 ]decan-8-ol (meth)acrylate, and (meth)acrylates having a monocyclic or polycyclic cycloalkyl group; (meth)acrylate cyclobutylene oxide, (meth)acrylate 3-methyl-3-cyclobutylene oxide, (meth)acrylate 3-ethyl-3-cyclobutylene oxide, (meth)acrylate (3-methyl-3-cyclobutylene oxide) methyl, (meth)acrylate (3-ethyl-3-cyclobutylene oxide) methyl, (meth)acrylate 2-(3-methyl-3-cyclobutylene oxide) ethyl, (meth)acrylate 2-(3-ethyl-3-cyclobutylene oxide) ethyl, (meth)acrylate 2-[(3-methyl-3-cyclobutylene oxide)] (meth)acrylates having an oxocyclobutane group such as 2-[(3-ethyl-3-oxocyclobutane)methoxy]ethyl (meth)acrylate, 3-[(3-methyl-3-oxocyclobutane)methoxy]propyl (meth)acrylate, 3-[(3-ethyl-3-oxocyclobutane)methoxy]propyl (meth)acrylate, (meth)acrylate having an oxocyclopentane group such as tetrahydrofuranyl (meth)acrylate, (meth)acrylate having an oxocyclopentane group such as methyl (meth)acrylate; (meth)acrylates having an aryl group such as phenyl (meth)acrylate and benzyl (meth)acrylate. The unsaturated carboxylic acid derivative (d4) represented by formula (2) may be used alone or in combination of two or more. Among them, preferred are (meth)acrylates having an alkyl group and (meth)acrylates having an aryl group, and more preferred are methyl (meth)acrylate, butyl (meth)acrylate, and benzyl (meth)acrylate.

The ratio (content) of the structural unit (D) in the copolymer is not particularly limited, but is preferably 0 to 50 mol% relative to all the structural units constituting the copolymer, and its lower limit is more preferably 1 mol%, and its upper limit is more preferably 35 mol%. By making the ratio of the structural unit (D) 1 mol% or more (especially 5 mol% or more), there is a tendency to effectively exhibit the function of imparting hardness to the cured product (cured film), the function of smoothing the copolymerization reaction, the function of improving solubility in the solvent, and the function of improving adhesion to the substrate. If the ratio of the structural unit (D) is below the above upper limit, the ratio of the structural units (A) to (C) becomes relatively large, and therefore there is a tendency to effectively exhibit the functions of these structural units.

When the copolymer of the present invention comprises structural unit (A), structural unit (B) and structural unit (C) but does not comprise structural unit (D), the total amount of structural units (A) to (C) relative to all structural units constituting the copolymer is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 99 mol% or more, and may be substantially 100 mol%. In addition, when the copolymer of the present invention comprises structural unit (A), structural unit (B), structural unit (C) and structural unit (D), the total amount of structural units (A) to (D) relative to all structural units constituting the copolymer is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 99 mol% or more, and may be substantially 100 mol%.

The weight average molecular weight (Mw) of the copolymer of the present invention is not particularly limited, for example, preferably 5000 to 70000, more preferably 7000 to 20000. The molecular weight distribution (ratio of weight average molecular weight to number average molecular weight: Mw/Mn) of the copolymer of the present invention is not particularly limited, for example, preferably 3.5 or less (e.g. 1.1 to 3.5), more preferably 2.5 or less (1.1 to 2.5). The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured, for example, by GPC (gel permeation chromatography) using polystyrene as a standard substance, preferably by the method used in the embodiments.

The acid value of the copolymer of the present invention is, for example, about 30 to 120 mgKOH/g, preferably about 40 to 100 mgKOH/g. By making the acid value within the above range, there is a tendency for excellent developing properties. In addition, the method for measuring the acid value of the copolymer is not particularly limited, for example, it can be measured by the method described in the embodiment.

The copolymer of the present invention has excellent manufacturing stability and storage stability, and has excellent curing properties. That is, it will cure even at relatively low temperatures, and the cured product has excellent solvent resistance. In addition, the curable resin composition containing the above-mentioned copolymer has excellent storage stability, and will cure even at relatively low temperatures, and the cured product has excellent solvent resistance. In addition, its cured product has excellent solvent resistance and high insulation, so it is more useful as a material for forming a protective film or an insulating film. In addition, since the copolymer of the present invention has excellent storage stability of its cured product, it is more useful as an adhesive resin or a pigment dispersion resin. ＜Method for producing copolymer＞

The copolymer of the present invention can be obtained by copolymerizing the compounds corresponding to the aforementioned structural units (A) to (C) and the compound corresponding to the aforementioned structural unit (D) as required. In addition, the copolymer of the present invention can be produced by copolymerizing the compound (a) represented by the aforementioned formula (1), the polymerizable unsaturated compound (b) containing an epoxy group, and at least one compound selected from the group consisting of the aforementioned (d1) to (d4) as required, and then adding the epoxy group of the polymerizable unsaturated compound (c) containing an epoxy group to a part of the carboxyl groups of the obtained copolymer. Hereinafter, the compounds that can be introduced into the copolymer, such as the compound (a) represented by the formula (1), are sometimes collectively referred to as "monomers".

The copolymerization reaction of the monomers can also be carried out in the presence of a polymerization initiator. As the above-mentioned polymerization initiator, a conventional or well-known free radical polymerization initiator can be used, for example, azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), diethyl-2,2'-azobis(2-methylpropionate), dibutyl-2,2'-azobis(2-methylpropionate), benzoyl peroxide, lauryl peroxide, tert-butyl peroxypivalate, 1,1-bis(tert-butylperoxy)cyclohexane, hydrogen peroxide, etc. When peroxide is used as a free radical polymerization initiator, a reducing agent may be combined to form a redox initiator. Among them, azo compounds are preferred, and 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobis(2-methylpropionate) are more preferred.

The amount of the polymerization initiator used is not particularly limited as long as it does not hinder the smooth copolymerization reaction. For example, relative to the total amount of the monomers (100 parts by weight), it is preferably 1 to 20 parts by weight, and more preferably 3 to 15 parts by weight.

The copolymerization reaction can be carried out by conventional methods used in the production of acrylic polymers and styrene polymers, such as solution polymerization, bulk polymerization, suspension polymerization, bulk-suspension polymerization, and emulsion polymerization. The monomer and the polymerization initiator can be supplied to the reaction system in bulk, or part or all of them can be added dropwise to the reaction system. For example, the following methods can be used: a method of performing polymerization by dropping a solution prepared by dissolving the polymerization initiator in a polymerization solvent into a monomer or a mixture of a monomer and a polymerization solvent maintained at a certain temperature; a method of performing polymerization by dropping a solution prepared by dissolving the monomer and the polymerization initiator in a polymerization solvent in advance into a polymerization solvent maintained at a certain temperature (dropping polymerization method), etc.

The polymerization solvent can be appropriately selected according to the monomer composition, etc., and examples thereof include ethers (chain ethers such as diethyl ether; ethylene glycol mono- or dialkyl ethers, diethylene glycol mono- or dialkyl ethers, propylene glycol mono- or dialkyl ethers, propylene glycol mono- or diaryl ethers, dipropylene glycol mono- or dialkyl ethers, tripropylene glycol mono- or dialkyl ethers, 1,3-propylene glycol mono- or dialkyl ethers, 1,3-butylene glycol mono- or dialkyl ethers, 1,4-butylene glycol mono- or dialkyl ethers, glycerol mono-, di- or tri-alkyl ethers, etc.; cyclic ethers such as tetrahydrofuran and dioxane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, C _5-6 cycloalkanediol mono- or diacet ... _5-6 Cycloalkane dimethanol mono- or diacetate and other carboxylic acid esters; ethylene glycol monoalkyl ether acetate, ethylene glycol mono- or diacetate, diethylene glycol monoalkyl ether acetate, diethylene glycol mono- or diacetate, propylene glycol monoalkyl ether acetate, propylene glycol mono- or diacetate, dipropylene glycol monoalkyl ether acetate, dipropylene glycol mono- or diacetate, 1,3-propylene glycol monoalkyl ether acetate, 1,3-propylene glycol mono- or diacetate, 1,3-butylene glycol monoalkyl ether acetate, 1,3-butylene glycol mono- or diacetate, 1,4-butylene glycol monoalkyl ether acetate, 1,4-butylene glycol mono- or diacetate, glycerol mono-, di- or triacetate, glycerol mono- or di-C _1-4 alkyl ether di- or monoacetates, tripropylene glycol monoalkyl ether acetate, tripropylene glycol mono- or diacetate, etc., glycol acetates or glycol ether acetates, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 3,5,5-trimethyl-2-cyclohexene-1-one, etc.), amides (N,N-dimethylacetamide, N,N-dimethylformamide, etc.), sulfoxides (dimethyl sulfoxide, etc.), alcohols (methanol, ethanol, propanol, C _5-6 cycloalkanediol, C _5-6 cycloalkane dimethanol, etc.), hydrocarbons (aromatic hydrocarbons such as benzene, toluene, xylene, aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, etc.), mixed solvents thereof, etc.

The reaction temperature in the polymerization reaction can be appropriately selected according to the type and composition of the monomers and is not particularly limited. For example, it is preferably 30 to 150°C.

The following is a description of the method for producing the copolymer of the present invention by copolymerizing the compound (a) represented by the aforementioned formula (1), the polymerizable unsaturated compound (b) containing an epoxy group, and, if necessary, at least one compound selected from the group consisting of the aforementioned (d1) to (d4), and then adding the epoxy group of the polymerizable unsaturated compound (c) containing an epoxy group to a portion of the carboxyl groups of the obtained copolymer.

The addition reaction of the aforementioned compound (C) can also be carried out in the presence of a catalyst. Examples of the aforementioned catalyst include: tertiary amines such as dimethylbenzylamine, triethylamine, tetramethylethylenediamine, tri-n-octylamine, and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU); quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and tetrabutylammonium bromide; alkyl ureas such as tetramethylurea; alkyl guanidines such as tetramethylguanidine; metal compounds (metal salts, etc.) such as cobalt cycloalkanoate; organometallic complexes; phosphine compounds (especially tertiary phosphines) such as triphenylphosphine, etc. These catalysts can be used alone or in combination of two or more.

The amount of the catalyst used is not particularly limited, for example, it is preferably 0.01 to 30% by weight relative to the epoxy-containing polymerizable unsaturated compound (c), the lower limit of which is more preferably 0.1% by weight, and more preferably 1% by weight. In addition, the upper limit of which is more preferably 25% by weight, and more preferably 20% by weight.

The addition reaction is usually carried out in the presence of a solvent. The solvent is not particularly limited as long as it can dissolve the raw materials, and for example, the solvents exemplified as the polymerization solvents mentioned above can be used.

The reaction temperature during the addition reaction is not particularly limited, and is preferably 10 to 150° C., more preferably 60 to 100° C. During the addition reaction, a polymerization inhibitor may be added to the reaction system to inhibit gelation caused by polymerization of polymerizable unsaturated groups. Examples of the polymerization inhibitor include p-methoxyphenol, hydroquinone, hydroquinone monomethyl ether, and phenanthridine.

In the method for producing the copolymer of the present invention, the obtained reaction product can be purified by precipitation or reprecipitation as needed. The solvent used for precipitation or reprecipitation can be any one of an organic solvent and water, and can also be a mixed solvent thereof. Examples of the organic solvent include: hydrocarbons (aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene), halogenated hydrocarbons (halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene, etc.), nitro compounds (nitromethane, nitroethane, etc.), nitriles (acetonitrile, benzonitrile, etc.), ethers (diethyl ether, dichloromethane, etc.), and nitriles (acetonitrile, benzonitrile, etc.). Chain ethers such as isopropyl ether and dimethoxyethane; cyclic ethers such as tetrahydrofuran and dioxane), ketones (acetone, methyl ethyl ketone, diisobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), carbonates (dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), alcohols (methanol, ethanol, propanol, isopropanol, butanol, etc.), carboxylic acids (acetic acid, etc.), and mixed solvents containing these solvents. <Curing resin composition>

The curable resin composition of the present invention is characterized in that it contains the copolymer of the present invention. In addition, it may also contain curable compounds other than the copolymer of the present invention, photopolymerization initiators, and solvents.

The curable compound other than the copolymer of the present invention is not particularly limited, and examples thereof include polyfunctional vinyl compounds, polyfunctional thiol compounds, and polyfunctional epoxy compounds.

The polyfunctional vinyl compound is not particularly limited as long as it is a compound having two or more vinyl groups. Examples thereof include: di(meth)acrylates of alkylene glycols such as ethylene glycol and propylene glycol; di(meth)acrylates of polyalkylene glycols such as polyethylene glycol and polypropylene glycol; di(meth)acrylates of polymers having hydroxylation at both ends such as polybutadiene having hydroxylation at both ends, polyisoprene having hydroxylation at both ends, and polycaprolactone having hydroxylation at both ends; di(meth)acrylates of glycerol, 1,2,4-butanetriol, trihydroxymethylalkane, Poly (meth) acrylates of trivalent or higher polyols such as tetrahydroxymethylalkanes, pentaerythritol, dipentaerythritol (e.g. dipentaerythritol hexaacrylate); poly (meth) acrylates of polyalkylene glycol adducts of trivalent or higher polyols; poly (meth) acrylates of cyclic polyols such as 1,4-cyclohexanediol and 1,4-benzenediol; oligo (meth) acrylates such as polyester (meth) acrylates, epoxy (meth) acrylates, (meth) urethane acrylates, silicone (meth) acrylates, etc. The multifunctional vinyl compounds may be used alone or in combination of two or more.

The polyfunctional thiol compound is not particularly limited as long as it is a compound having two or more thiol groups, and examples thereof include hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene glycol bisthioglycolate, ethylene glycol bisthiopropionate, trihydroxymethylpropane trithioglycolate, trihydroxymethylpropane trithiopropionate, trihydroxymethylpropane tris(3-butylbutyrate), pentaerythritol tetrathioglycolate, pentaerythritol tetrathiopropionate, tris(2-hydroxyethyl)isocyanurate of tris(butyl)propionate, 1,4-dimethylbenzene, 2- ,4,6-tris(butyl)-symmetric tris(iodine), 2-(N,N-dibutylamino)-4,6-dibutyl-symmetric tris(iodine), tetraethylene glycol bis(3-butyl)propionate, trihydroxymethylpropane tris(3-butyl)propionate, isocyanuric acid tris(3-butyl)propynyloxyethyl)ester, pentaerythritol tetra(3-butyl)propionate, dipentaerythritol tetra(3-butyl)propionate, 1,4-bis(3-butylbutyryloxy)butane, 1,3,5-tris(3-butylbutoxyethyl)-1,3,5-tris(iodine-2,4,6(1H,3H,5H)-trione, pentaerythritol tetra(3-butyl)butyrate, etc. The multifunctional thiol compound may be used alone or in combination of two or more.

The polyfunctional epoxy compound is not particularly limited as long as it is a compound having two or more epoxy groups. Examples thereof include: glycidyl ether-type epoxy compounds [glycidyl ethers (e.g., ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, etc.) generated by the reaction of a polyhydroxy compound (bisphenols, polyphenols, alicyclic polyols, aliphatic polyols, etc.) with epichlorohydrin; _2-4 -Alkanediol diglycidyl ether; diglycidyl ether of polyphenols such as resorcinol and hydroquinone; diglycidyl ether of alicyclic polyols such as cyclohexanediol, cyclohexane dimethanol, and hydrogenated bisphenols; bisphenols (4,4'-dihydroxybiphenyl, bisphenol A and other bis(hydroxyphenyl)alkanes, etc.) or CC _2-3 alkylene oxide adduct diglycidyl ether, etc.), novolac type epoxy resin (phenol novolac type or cresol novolac type epoxy resin, etc.), glycidyl ester type epoxy compound, alicyclic epoxy compound (or epoxide aliphatic epoxy resin), heterocyclic epoxy resin (triglycidyl isocyanurate (TGIC), hydantoin type epoxy resin, etc.), glycidylamine type epoxy compound [reaction of amines with epichlorohydrin products, such as N-glycidyl aromatic amines {tetraglycidyl diamino diphenylmethane (TGDDM), triglycidyl amino phenol (TGPAP, TGMAP, etc.), diglycidyl aniline (DGA), diglycidyl toluidine (DGT), tetraglycidyl dimethylbenzene diamine (TGMXA, etc.), N-glycidyl alicyclic amines (tetraglycidyl diamino cyclohexane, etc.), etc.], etc. The multifunctional epoxy compound can be used alone or in combination of two or more.

In the present invention, the photopolymerization initiator is not particularly limited, and examples thereof include photoradical polymerization initiators and photocationic polymerization initiators.

The photo-radical polymerization initiator is a compound that generates free radicals by irradiation with light, thereby initiating the curing reaction (free radical polymerization) of the photopolymerizable compound contained in the curable resin composition. The photo-radical polymerization initiator can be used alone or in combination of two or more.

Examples of photoradical polymerization initiators include thioxanthone (also known as 9-oxothioxanthene) compounds, acetophenone compounds, biimidazole compounds, trioxane compounds, oxime compounds, onium salt compounds, benzoin compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, diazo compounds, imide sulfonate compounds, anthracene compounds, and the like.

Examples of the thioxanthrone compounds include thioxanthrone, 2-chlorothioxanthrone, 2-methylthioxanthrone, 2-isopropylthioxanthrone, 4-isopropylthioxanthrone, 2,4-dimethylthioxanthrone, 2,4-diethylthioxanthrone, 2,4-diisopropylthioxanthrone, 2,4-dichlorothioxanthrone, and 1-chloro-4-propoxythioxanthrone.

Examples of the acetophenone compounds include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzyl dimethyl ketal, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)butane-1-one, 2-(2-methylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(3-methylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, and 2-(4-morpholinylphenyl)-1-(2-methylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone. )-butanone, 2-(4-methylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(2-ethylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(2-propylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(2-butylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(2,3-dimethylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(2,4-dimethylbenzyl)-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, 2-(2-chlorobenzyl)- 2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(2-bromobenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(3-chlorobenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(4-chlorobenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(3-bromobenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(4-bromobenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(2-methoxybenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2 -(3-methoxybenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(4-methoxybenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(2-methyl-4-methoxybenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(2-methyl-4-bromobenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, 2-(2-bromo-4-methoxybenzyl)-2-dimethylamino-1-(4-fluorinylphenyl)-butanone, oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one, etc.

Examples of the biimidazole compound include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(alkoxyphenyl)biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(dialkoxyphenyl)biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(trialkoxyphenyl)biimidazole, and imidazole compounds in which the phenyl groups at the 4,4',5,5'-positions are substituted with alkoxycarbonyl groups.

Examples of the trioxane compounds include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-trioxane, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-trioxane, 2,4-bis(trichloromethyl)-6-sunfloweryl-1,3,5-trioxane, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-trioxane, 2,4-bis(trichloromethyl)-6-sunfloweryl-1,3,5-trioxane, -[2-(5-methylfuran-2-yl)vinyl]-1,3,5-trisin, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-trisin, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)vinyl]-1,3,5-trisin, 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-trisin, etc.

Examples of the oxime compound include O-ethoxycarbonyl-α-oxyimino-1-phenylpropane-1-one and the like.

Examples of the benzoin-based compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

Examples of the benzophenone compounds include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetrakis(tertiary butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone.

Examples of the anthracene compound include 9,10-dimethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 2-ethyl-9,10-diethoxyanthracene.

The photo-cationic polymerization initiator is a compound that generates acid by irradiation with light, thereby initiating the curing reaction (cationic polymerization) of the photopolymerizable compound contained in the curable resin composition, and includes a cationic part that absorbs light and an anionic part that becomes a source of acid generation. The photo-cationic polymerization initiator can be used alone or in combination of two or more.

Examples of the photocatalytic polymerization initiator include diazonium salt compounds, iodonium salt compounds, coronium salt compounds, phosphonium salt compounds, selenium salt compounds, oxonium salt compounds, ammonium salt compounds, and bromine salt compounds.

Examples of the anion portion of the photocatalytic polymerization initiator include: [(Y) _sB (Phf) _4-s ] ^- (wherein Y represents a phenyl group or a biphenyl group. Phf represents a phenyl group in which at least one hydrogen atom is substituted by at least one selected from a perfluoroalkyl group, a perfluoroalkoxy group and a halogen atom. s is an integer from 0 to 3 ⁾ , _BF4- , [(Rf) _{kPF6 -k} ] ^- (Rf: an alkyl group in which more than 80% of the hydrogen atoms are substituted by fluorine atoms, k: an integer from 0 to 5), _AsF6- ^, _SbF6- ^, _SbF5OH- ^, etc.

Examples of the photocatalytic polymerization initiator include (4-hydroxyphenyl)methylbenzylcopperium tetrakis(pentafluorophenyl)borate, 4-(4-biphenylthio)phenyl-4-biphenylphenylcopperium tetrakis(pentafluorophenyl)borate, 4-(phenylthio)phenyldiphenylcopperium tris(pentafluorophenyl)borate, [4-(4-biphenylthio)phenyl]-4-biphenylphenylcopperium tris(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]copperium tris(pentafluoroethyl)trifluorophosphate, tetrakis(pentafluorophenyl)borate, phenyl) borate, diphenyl [4- (phenylthio) phenyl] coronium hexafluorophosphate, tris (pentafluoroethyl) 4- (4-biphenylthio) phenyl-4-biphenylphenyl coronium trifluorophosphate, phenyl tris (pentafluorophenyl) borate bis [4- (diphenyl dihydrothio) phenyl] sulfide, phenyl tris (pentafluorophenyl) borate [4- (2-thioanthrylthio) phenyl] phenyl-2-thioanthryl coronium, 4- (phenylthio) phenyl diphenyl coronium hexafluoroantimonate, etc.

As the photopolymerization initiator, the following can be used: "CYRACURE UVI-6970", "CYRACURE UVI-6974", "CYRACURE UVI-6990", "CYRACURE UVI-950" (all manufactured by Union Carbide), "Irgacure 250", "Irgacure 261", "Irgacure 264" (all manufactured by BASF), "CG-24-61" (manufactured by Ciba-Geigy), "Optomer SP-150", "Optomer SP-151", "Optomer SP-170", "Optomer SP-171" (all manufactured by ADEKA Co., Ltd.), "DAICAT II" (manufactured by Daicel Co., Ltd.), "UVAC1590", "UVAC1591" (all manufactured by Daicel-Cytec Co., Ltd.), "CI-2064", "CI-2639", "CI-2624", "CI-2481", "CI-2734", "CI-2855", "CI-2823", "CI-2758", "CIT-1682" (all manufactured by Nippon Soda Co., Ltd.) Co., Ltd.), "PI-2074" (manufactured by Rhodia, cumyl tetrakis(pentafluorophenyl)borate), "FFC509" (manufactured by 3M), "BBI-102", "BBI-101", "BBI-103", "MPI-103", "TPS-103", "MDS-103", "DTS-103", "NAT-103", "NDS-103" (all manufactured by Midori Kagaku Co., Ltd.), "CD-1010", "CD-1011", "CD-1012" (all manufactured by Sartomer Americas), "CPI-100P", "CPI-101A" (all manufactured by San-Apro Co., Ltd.), etc.

The content of the photopolymerization initiator (the total amount when two or more are contained) is preferably 0.1 to 100 parts by weight, for example, with the lower limit being more preferably 0.5 parts by weight, and more preferably 3 parts by weight, relative to 100 parts by weight of the photopolymerizable compound (total amount) contained in the curable resin composition. In addition, the upper limit is more preferably 50 parts by weight, and more preferably 20 parts by weight. If the content of the photopolymerization initiator is lower than the above range, the curability tends to decrease. On the other hand, if the content of the photopolymerization initiator exceeds the above range, the cured product tends to be easily colored. <Solvent>

Examples of the solvent include ethers (chain ethers such as diethyl ether; glycol ethers such as ethylene glycol mono- or dialkyl ethers, diethylene glycol mono- or dialkyl ethers, propylene glycol mono- or dialkyl ethers, propylene glycol mono- or diaryl ethers, dipropylene glycol mono- or dialkyl ethers, tripropylene glycol mono- or dialkyl ethers, 1,3-propylene glycol mono- or dialkyl ethers, 1,3-butylene glycol mono- or dialkyl ethers, 1,4-butylene glycol mono- or dialkyl ethers, glycerol mono-, di- or trialkyl ethers; cyclic ethers such as tetrahydrofuran and dioxane), esters (methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, C _5-6 cycloalkanediol mono- or diacet ... _5-6 Cycloalkane dimethanol mono- or diacetate and other carboxylic acid esters; ethylene glycol monoalkyl ether acetate, ethylene glycol mono- or diacetate, diethylene glycol monoalkyl ether acetate, diethylene glycol mono- or diacetate, propylene glycol monoalkyl ether acetate, propylene glycol mono- or diacetate, dipropylene glycol monoalkyl ether acetate, dipropylene glycol mono- or diacetate, 1,3-propylene glycol monoalkyl ether acetate, 1,3-propylene glycol mono- or diacetate, 1,3-butylene glycol monoalkyl ether acetate, 1,3-butylene glycol mono- or diacetate, 1,4-butylene glycol monoalkyl ether acetate, 1,4-butylene glycol mono- or diacetate, glycerol mono-, di- or triacetate, glycerol mono- or di-C _1-4 alkyl ether di- or monoacetate, tripropylene glycol monoalkyl ether acetate, tripropylene glycol mono- or diacetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 3,5,5-trimethyl-2-cyclohexene-1-one, etc.), etc. These solvents may be used alone or in combination of two or more.

In addition to the above-mentioned components, the curable resin composition of the present invention may also contain, for example, resins such as novolac resins, phenolic resins, imide resins, carboxyl-containing resins, curing agents, curing accelerators, additives (fillers, defoaming agents, flame retardants, antioxidants, ultraviolet absorbers, colored materials (colorants), low stress agents, flexibility imparting agents, waxes, crosslinking agents, halogen scavengers, leveling agents, wetting improvers, etc.).

The content of the copolymer in the curable resin composition of the present invention is not particularly limited, for example, 3 to 40% by weight. In addition, the content of the copolymer relative to the total amount of the curable compound contained in the curable resin composition is not particularly limited, for example, preferably 20% by weight or more, more preferably 30% by weight or more, further preferably 40% by weight or more, and particularly preferably 50% by weight or more.

When the curable resin composition of the present invention contains a colored material, it can be used as a photosensitive resin composition. As a method for preparing a photosensitive resin composition, for example, the following method can be cited: a pigment dispersant is optionally present in a solvent, and a colored material such as a pigment is dispersed to prepare a colored material dispersion liquid, and an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and other additives as required are dissolved in the solvent, and the mixture is mixed with the aforementioned colored material dispersion liquid, and a solvent is further added as required.

The photosensitive resin composition of the present invention is usually sealed in a container for circulation and storage. The photosensitive resin composition of the present invention has excellent storage stability during circulation and storage. [Solidified material]

By curing the curable resin composition of the present invention, a cured product with excellent physical properties can be obtained. For example, the curable resin composition can be applied to various substrates or base plates by conventional coating methods such as a spin coater, a dip coater, a roll coater, a slot coater, etc. to form a coating film, and then the coating film is cured to obtain a cured product. Curing is performed, for example, by subjecting the curable resin composition to light irradiation and/or heat treatment.

The aforementioned light irradiation is preferably performed using, for example, a mercury lamp, a xenon lamp, a carbon arc lamp, a metal halide lamp, sunlight, an electron beam source, a laser light source, an LED light source, etc., and the irradiation is performed in a cumulative irradiation amount in the range of, for example, 500 to 5000 mJ/ ^cm2 .

The aforementioned heat treatment is preferably performed at a temperature of, for example, 60 to 300° C. (preferably 100 to 250° C.) for, for example, 1 to 120 minutes (preferably 1 to 60 minutes).

Examples of the substrate or base include silicon wafers, metals, plastics, glass, ceramics, etc. The thickness of the cured coating is preferably 0.05 to 20 µm, more preferably 0.1 to 10 µm.

The cured product (coating film after curing) of the present invention has excellent solvent resistance and high insulation, and is therefore useful as a protective film or insulating film. In addition, it is also useful as a material for forming a color filter protective film, a microlens, a coloring pattern, a transparent film, and the like.

When the curable resin composition of the present invention contains a colored material, the cured product thereof can be used as a color filter. The color filter may also have a colored pattern formed by the photosensitive resin composition. The color filter may be manufactured, for example, by forming a colored pattern on a substrate using the photosensitive resin composition and post-baking the colored pattern.

The various aspects disclosed in this specification can also be combined with any other features disclosed in this specification. Each structure and its combination in each implementation method is an example, and the addition, omission, replacement and other changes of the structure can be appropriately made within the scope of the subject matter of the invention. In addition, the inventions of the present invention are not limited by the implementation methods and the following embodiments, but only by the scope of the patent application. Implementation examples

The present invention is described in more detail below based on embodiments, but the present invention is not limited to these embodiments.

The acid value of the copolymer is determined by neutralization titration using a 0.1N-NaOH standard solution. Weigh 0.5g of the resin solution, add 70mL of THF and 10mL of distilled water. Add 2 or 3 drops of phenolphthalein solution as an indicator and stir to make it uniform. While stirring the solution, titrate with a 0.1mol/L NaOH aqueous solution, set the point where the solution changes from colorless to pink as the end point, and calculate the acid value using the following formula. Acid value (KOHmg/g) = A×F×5.6/S/non-volatile component (%)×100 (In the formula, A is the amount of 0.1mol/L NaOH aqueous solution added until the end point (mL), F is the coefficient of 0.1N-NaOH aqueous solution, and S is the sample collection amount (g)) [Production Example 1]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 160 g of propylene glycol monomethyl ether acetate and 110 g of 1-methoxy-2-propanol were added, and the mixture was heated to 80°C while stirring. Then, a solution prepared by dissolving 254 g of 2-acryloyloxyethyl succinate as a monomer and 76 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100) in 180 g of propylene glycol monomethyl ether acetate, and a mixed solution prepared by dissolving 20 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 200 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-1) with a solid content of 33.4% by weight. The weight average molecular weight Mw of the generated copolymer was 8,100, the dispersity was 1.80, and the acid value was 200 KOHmg/g. [Production Example 2]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was circulated to form a nitrogen atmosphere, 145 g of propylene glycol monomethyl ether acetate and 110 g of 1-methoxy-2-propanol were added, and the mixture was heated to 80°C while stirring. Then, a solution prepared by dissolving 223 g of 2-acryloyloxyethyl succinate as a monomer, 68 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100), and 38 g of styrene (ST) in 180 g of propylene glycol monomethyl ether acetate, and a mixed solution prepared by dissolving 35 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 200 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-2) with a solid content of 33.6% by weight. The weight average molecular weight Mw of the generated copolymer was 5,500, the dispersity was 1.67, and the acid value was 175 KOHmg/g. [Production Example 3]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 161 g of propylene glycol monomethyl ether acetate and 110 g of 1-methoxy-2-propanol were added, and the mixture was heated to 80°C while stirring. Then, a solution prepared by dissolving 209 g of 2-acryloyloxyethyl succinate, 63 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100) and 58 g of cyclohexyl cis-butylene diimide (CHMI) in 180 g of propylene glycol monomethyl ether acetate as a monomer, and a mixed solution prepared by dissolving 19 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 200 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-3) with a solid content of 33.4% by weight. The weight average molecular weight Mw of the generated copolymer was 8,300, the dispersity was 1.69, and the acid value was 165 KOHmg/g. [Production Example 4]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 168 g of propylene glycol monomethyl ether acetate and 110 g of 1-methoxy-2-propanol were added, and the mixture was heated to 80°C while stirring. Then, a solution prepared by dissolving 138 g of 2-acryloyloxyethyl succinate as a monomer, 98 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100), and 94 g of benzyl methacrylate (BzMA) in 180 g of propylene glycol monomethyl ether acetate, and a mixed solution prepared by dissolving 12 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 200 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-4) with a solid content of 33.3% by weight. The weight average molecular weight Mw of the generated copolymer was 17,100, the dispersity was 2.19, and the acid value was 108KOHmg/g. [Production Example 5]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 162 g of propylene glycol monomethyl ether acetate and 110 g of 1-methoxy-2-propanol were added, and the mixture was heated to 80°C while stirring. Then, a solution prepared by dissolving 220 g of 2-acryloyloxyethyl succinate, 50 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100) and 60 g of butyl methacrylate (BMA) in 180 g of propylene glycol monomethyl ether acetate as a monomer, and a mixed solution prepared by dissolving 18 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 200 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-5) with a solid content of 33.7% by weight. The weight average molecular weight Mw of the generated copolymer was 9,900, the dispersity was 2.06, and the acid value was 173KOHmg/g. [Production Example 6]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 95 g of propylene glycol monomethyl ether acetate and 220 g of 1-methoxy 2-propanol were added, and the mixture was heated to 65°C while stirring. Then, a solution prepared by dissolving 115 g of acrylic acid (AA) as a monomer and 205 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100) in 30 g of propylene glycol monomethyl ether acetate and 100 g of 1-methoxy 2-propanol, and a mixed solution prepared by dissolving 35 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 200 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-6) with a solid content of 32.5% by weight. The weight average molecular weight Mw of the generated copolymer was 11,000, the dispersity was 3.51, and the acid value was 276.4 KOHmg/g. [Production Example 7]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 74 g of propylene glycol monomethyl ether acetate and 190 g of 1-methoxy 2-propanol were added, and the mixture was heated to 65°C while stirring. Then, a solution prepared by dissolving 101 g of acrylic acid (AA) as a monomer, 162 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100), and 57 g of styrene (ST) in 130 g of 1-methoxy 2-propanol, and a mixed solution prepared by dissolving 36 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 250 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-7) with a solid content of 32.4% by weight. The weight average molecular weight Mw of the generated copolymer was 9,800, the dispersity was 3.36, and the acid value was 242.2 KOHmg/g. [Production Example 8]

In a 1 L flask equipped with a reflux cooler, a dropping funnel and a stirrer, an appropriate amount of nitrogen was circulated to create a nitrogen atmosphere, 8 g of propylene glycol monomethyl ether acetate and 210 g of 1-methoxy-2-propanol were added, and the mixture was heated to 65°C while stirring. Then, using a drop pump, a solution prepared by dissolving 131 g of methacrylic acid (MAA) as a monomer, 99 g of 3,4-epoxycyclohexylmethyl methacrylate (Cyclomer M100), and 91 g of cyclohexyl cis-butylene diimide (CHMI) in 60 g of propylene glycol monomethyl ether acetate and 110 g of 1-methoxy-2-propanol, and a mixed solution prepared by dissolving 42 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 250 g of propylene glycol monomethyl ether acetate were added dropwise over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-8) having a solid content of 32.3% by weight. The weight average molecular weight Mw of the resulting copolymer is 7,500, the dispersion is 2.21, and the acid value is 266.3 KOHmg/g. [Production Example 9]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 60 g of propylene glycol monomethyl ether acetate and 170 g of 1-methoxy 2-propanol were added, and the mixture was heated to 65°C while stirring. Then, a solution prepared by dissolving 104 g of methacrylic acid (MAA) as a monomer, 157 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100), and 89 g of benzyl methacrylate (BzMA) in 140 g of 1-methoxy 2-propanol, and a mixed solution prepared by dissolving 30 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 250 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-9) with a solid content of 35.8% by weight. The weight average molecular weight Mw of the generated copolymer was 8,400, the dispersity was 2.15, and the acid value was 193.9 KOHmg/g. [Production Example 10]

In a 1L flask equipped with a reflux cooler, a dropping funnel and a stirrer, a proper amount of nitrogen was passed to form a nitrogen atmosphere, 64 g of propylene glycol monomethyl ether acetate and 190 g of 1-methoxy 2-propanol were added, and the mixture was heated to 65°C while stirring. Then, a solution prepared by dissolving 122 g of acrylic acid (AA) as a monomer, 109 g of 3,4-epoxyhexylmethyl methacrylate (Cyclomer M100), and 79 g of butyl methacrylate (BMA) in 130 g of 1-methoxy 2-propanol, and a mixed solution prepared by dissolving 46 g of 2,2'-azobis(2,4-dimethylvaleronitrile) in 260 g of propylene glycol monomethyl ether acetate were added dropwise using a dropping pump over about 5 hours. After the addition of the mixed solution was completed, the temperature was maintained for about 3 hours, and then cooled to room temperature to obtain a copolymer solution (C-10) with a solid content of 31.4% by weight. The weight average molecular weight Mw of the generated copolymer was 10,700, the dispersity was 3.20, and the acid value was 302.7 KOHmg/g. [Example 1]

To the copolymer solution (C-1) obtained in Preparation Example 1, 78 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol were added and reacted at 90°C for 13 hours to obtain a copolymer solution (P-1). The reaction was carried out under a mixed gas flow of 6% oxygen and 94% nitrogen. [Example 2]

In addition to adding 55 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-2) obtained in Preparation Example 2, a copolymer solution (P-2) was obtained by the same method as Example 1. [Example 3]

In addition to adding 69 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-3) obtained in Preparation Example 3, a copolymer solution (P-3) was obtained by the same method as Example 1. [Example 4]

In addition to adding 43 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-4) obtained in Preparation Example 4, a copolymer solution (P-4) was obtained by the same method as Example 1. [Example 5]

In addition to adding 72 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-5) obtained in Preparation Example 5, a copolymer solution (P-5) was obtained by the same method as Example 1. [Comparative Example 1]

In addition to adding 112 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-6) obtained in Preparation Example 6, a copolymer solution (P-6) was obtained by the same method as Example 1. [Comparative Example 2]

In addition to adding 98 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-7) obtained in Preparation Example 7, a copolymer solution (P-7) was obtained by the same method as Example 1. [Comparative Example 3]

In addition to adding 108 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-8) obtained in Preparation Example 8, a copolymer solution (P-8) was obtained by the same method as Example 1. [Comparative Example 4]

In addition to adding 64 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol to the copolymer solution (C-9) obtained in Preparation Example 9, a copolymer solution (P-9) was obtained by the same method as Example 1. [Comparative Example 5]

A copolymer solution (P-10) was obtained by the same method as in Example 1, except that 127 g of glycidyl methacrylate (GMA), 3 g of triphenylphosphine (TPP) and 2 g of p-methoxyphenol were added to the copolymer solution (C-10) obtained in Preparation Example 10.

The copolymer solutions (P-1) to (P-10) obtained in Examples 1 to 5 and Comparative Examples 1 to 5 have copolymer compositions shown in Table 1. In addition, the molar ratio (mol%) of the structural units is recorded as the ratio of the usage amount of the corresponding compounds. Among them, the structural units (A) and (C) are calculated as follows.

The molar ratio of the structural unit (A) is calculated by subtracting the amount of the epoxy-containing polymerizable unsaturated compound (c) used from the amount of the compound (a) represented by the formula (1). This is based on the assumption that all of the epoxy-containing polymerizable unsaturated compound (c) used reacts with the carboxyl group of the compound (a) represented by the formula (1). The molar ratio of the structural unit (C) is the molar ratio of the epoxy-containing polymerizable unsaturated compound (c) used.

The following evaluation tests were conducted using the copolymer solutions (P-1) to (P-10) obtained in Examples 1 to 5 and Comparative Examples 1 to 5. The results are shown in Table 1. (Manufacturing stability test)

In Examples 1 to 5 and Comparative Examples 1 to 5, the copolymer solution after the reaction is gelled, which is recorded as "gelled" in Table 1. In addition, the weight average molecular weight (polystyrene conversion) of the copolymer solution obtained is measured, and the manufacturing stability is evaluated based on the value of the molecular weight distribution. In Table 1, the case where the molecular weight distribution is 2.5 or less is recorded as "◎", the case where it exceeds 2.5 and is 3.5 or less is recorded as "0", and the case where it exceeds 3.5 is recorded as "Δ". (Storage stability test)

The weight average molecular weight (polystyrene conversion) of the copolymer solutions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 was measured, and the weight average molecular weight was measured after being stored in an oven at 40°C for 2 weeks. The increase rate of the weight average molecular weight during the period was calculated using the following calculation formula, and the results are recorded in Table 1. P: weight average molecular weight before storage (just after synthesis), Q: weight average molecular weight after storage Weight average molecular weight increase rate (%) = {(Q/P) × 100}-100

In addition, the weight average molecular weight (polystyrene conversion) and molecular weight distribution (weight average molecular weight Mw/number average molecular weight Mn) of the copolymer were measured using the following device. Device: Detector: RID-20A (Shimadzu Corporation) Pump: LC-20AD (Shimadzu Corporation) System controller: CBM-20Alite (Shimadzu Corporation) Degasser: DGU-20A3 (Shimadzu Corporation) Automatic syringe: SIL-20A HT (Shimadzu Corporation) Column: Shodex KF-806L (Showa Denko) Solvent: THF (tetrahydrofuran) 0.8 ml/min Temperature: Oven: 40°C, RI: 40°C Detector: RI

Table 1

The copolymers of Examples 1 to 5 have excellent manufacturing stability and the weight average molecular weight is not easily increased even at 40°C, so the storage stability is also excellent. On the other hand, the copolymers of Comparative Examples 1, 2 and 5 gel during manufacturing and lack manufacturing stability. In addition, the copolymers of Comparative Examples 3 and 4 increase the weight average molecular weight at 40°C over time and lack storage stability. One of the reasons for this is that the copolymers of Examples 1 to 5 have structural units derived from 2-acryloyloxyethyl succinate, while the copolymers of Comparative Examples 1 to 5 do not have the aforementioned structural units. Specifically, the reason is that the side chain of the structural unit derived from 2-acryloyloxyethyl succinate contains an ester bond and has a certain degree of length, so the acidity of the copolymer as a whole becomes moderately low. Therefore, when the copolymer is produced, the reactivity of the epoxy group of the copolymer, that is, the alicyclic epoxy group derived from Cyclomer M100, decreases, and it is believed that the epoxy group derived from glycidyl methacrylate (GMA) preferably reacts with the carboxyl group derived from 2-acryloyloxyethyl succinate, so it is not easy to produce gelation. In addition, it is believed that the reaction between the carboxyl group and the epoxy group in the molecule of the copolymer is not easy to cause after production, so the weight average molecular weight does not increase over time. [Examples 6 to 10 and Comparative Examples 6 to 7]

The curable resin composition was prepared by mixing the specified components in the ratios listed in Table 2, and the following evaluation was performed. The results are shown in Table 2. In addition, the units of the components of the curable resin composition in the table are parts by weight. (Solvent resistance test)

After applying the curable resin composition obtained in Examples 6 to 10 and Comparative Examples 6 to 7 on a glass plate using a spin coater, the coating was pre-baked at 80°C for 3 minutes to form a coating film with a film thickness of about 5 µm. The resulting coating film was cured for 60 seconds using a high-pressure mercury lamp at 500W, and then heat-cured at 180°C for 15 minutes to prepare each evaluation specimen. In addition, each evaluation specimen was prepared using the same method except that 180°C was changed to 230°C.

For the above evaluation test piece, drop 1 drop of N-methylpyrrolidone (NMP) and γ-butyrolactone (γ-BL) respectively, and leave it for 10 minutes. Then wash it with water, and set the case where the drop of solvent is completely unchanged as ◎, the case where only traces of solvent are left as ○, the case where partial color change and swelling are set as Δ, and the case where the whole color change and dissolution are set as ×.

Table 2 Embodiment 6 Embodiment 7 Embodiment 8 Embodiment 9 Embodiment 10 Comparative Example 6 Comparison Example 7 Copolymer P-1 4.1 P-2 4.1 P-3 4.1 P-4 4.1 P-5 4.1 P-8 4.1 P-9 4.1 DPHA 1.3 1.3 1.3 1.3 1.3 1.3 1.3 IRG184 0.1 0.1 0.1 0.1 0.1 0.1 0.1 PEMP 0.1 0.1 0.1 0.1 0.1 0.1 0.1 MMP GAc 4.4 4.4 4.4 4.4 4.4 4.4 4.4 Evaluation of composition Solvent resistance 180℃ curing NMP ◎ ○ ◎ ○ ○ Δ Δ γ-BL ◎ ◎ ◎ ◎ ◎ ○ ○ Solvent resistance 230℃ curing NMP ◎ ◎ ◎ ◎ ◎ ○ ○ γ-BL ◎ ◎ ◎ ◎ ◎ ◎ ◎

The curable resin compositions of Examples 6 to 10 exhibited good solvent resistance even at a curing temperature of 180° C. as well as at 230° C. On the other hand, the curable resin compositions of Comparative Examples 6 and 7 exhibited poor solvent resistance.

The following is a description of the ingredients used in Tables 1 and 2. AES: 2-Acryloyloxyethyl Succinate (manufactured by Kyoeisha Chemical Co., Ltd.) AA: Acrylic Acid (manufactured by Mitsubishi Chemical Co., Ltd.) MAA: Methacrylic Acid (manufactured by Mitsubishi Chemical Co., Ltd.) M100: 3,4-Epoxycyclohexylmethyl Methacrylate, (trade name "Cyclomer M100", manufactured by Daicel Co., Ltd.) GMA: Glycidyl Methacrylate (manufactured by NOF Corporation) ST: Styrene (manufactured by Fuji Film Wako Pure Chemical Co., Ltd.) CHMI: N-Cyclohexyl cis-butylene diimide (manufactured by Nippon Catalyst Co., Ltd.) BzMA: Benzyl Methacrylate (manufactured by Mitsubishi Chemical Co., Ltd.) BMA: Butyl Methacrylate (manufactured by Mitsubishi Chemical Co., Ltd.) DPHA: Dipentaethoxyethanol hexaacrylate (manufactured by DAICEL-ALLNEX Co., Ltd.) IRG184: 1-Hydroxycyclohexylphenyl ketone, (manufactured by BASF Japan Co., Ltd.) PEMP: Pentaerythritol tetra(3-pentylpropionate) (manufactured by Showa Denko Co., Ltd.) MMPGAc: Propylene glycol monomethyl ether acetate (manufactured by DAICEL Co., Ltd.)

In summary, the structure and variations of the present invention are described below. [1] A copolymer comprising a structural unit (A) derived from a compound (a) represented by the above formula (1) (wherein R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms; R ^2a represents a divalent organic group; ^Xa represents a heteroatom); a structural unit (B) derived from an epoxy-containing polymerizable unsaturated compound (b); and a structural unit (C) derived from an addition reaction product of the compound (a) represented by the above formula (1) and an epoxy-containing polymerizable unsaturated compound (c), and having a carboxyl group derived from the compound (a) represented by the above formula (1); an epoxy group derived from the epoxy-containing polymerizable unsaturated compound (b); and a polymerizable unsaturated group derived from the epoxy-containing polymerizable unsaturated compound (c). [2] The copolymer as described in [1], which is obtained by subjecting a copolymer comprising the aforementioned structural unit (A) and the aforementioned structural unit (B) to an addition reaction with the aforementioned compound (c). [3] The copolymer as described in [1] or [2], wherein in the aforementioned compound (a), R ^1a of the formula (1) represents a hydrogen atom. [4] The copolymer as described in any one of [1] to [3], wherein in the aforementioned compound (a), R ^2a of the formula (1) represents a divalent organic group containing an ester bond. [5] The copolymer as described in any one of [1] to [4], wherein in the aforementioned compound (a), R ^2a in the formula (1) represents a group formed by two alkylene groups connected via a linking group bond, a group formed by two alkylene groups connected via an ester bond, or a -C ₂ H ₄ -O-(C=O)-C ₂ H ₄ - group (the bond extending from the left C ₂ H ₄ group to the left is bonded to X ^a , and the bond extending from the right C ₂ H ₄ group to the right is bonded to the carbon atom of the (C=O)-OH group). [6] The copolymer as described in any one of [1] to [5], wherein in the aforementioned compound (a), the heteroatom in X ^a in the formula (1) represents a nitrogen atom, an oxygen atom, or a sulfur atom. [7] The copolymer as described in any one of [1] to [6], wherein the ratio of the structural unit (A) in the copolymer is 10 to 50 mol% relative to all the structural units constituting the copolymer, with a lower limit of 20 mol% or an upper limit of 40 mol%. [8] The copolymer as described in any one of [1] to [7], wherein the epoxy group of the compound (b) is an alicyclic epoxy group. [9] The copolymer as described in any one of [1] to [8], wherein the epoxy group of the compound (b) is a monocyclic or bicyclic alicyclic epoxy group. [10] A copolymer as described in any one of [1] to [9], wherein the compound (b) is a compound represented by the above formula (2) (wherein R ^1b represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2b each represents an alkyl group having 1 to 7 carbon atoms, the same or different from each other. X ^b represents a single bond or a divalent organic group. In addition, R ^2b represents a substituent on the cyclohexane ring represented by formula (2), which is not included in the substituents possessed by Y ^b . Y ^b represents an unbonded group (meaning that there is no group corresponding to Y ^b ), a methylene group or an ethylene group which may have an alkyl group having 1 to 3 carbon atoms as a substituent, an oxygen atom, or a sulfur atom which may be bonded to an oxygen atom. n represents an integer greater than 0 (preferably an integer from 0 to 7)). [11] A copolymer as described in any one of [1] to [10], wherein the compound (b) is a compound represented by the above formula (2') (wherein R ^1b represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2b each represents an alkyl group having 1 to 7 carbon atoms, the same or different from each other. X ^b represents a single bond or a divalent organic group. In addition, R ^2b represents a substituent on the cyclohexane ring represented by formula (2'), which is not included in the substituents possessed by Y ^b . Y ^b represents an unbonded group (meaning that there is no group corresponding to Y ^b ), a methylene group or an ethylene group which may have an alkyl group having 1 to 3 carbon atoms as a substituent, an oxygen atom, or a sulfur atom which may be bonded to an oxygen atom. n represents an integer greater than 0 (preferably an integer from 0 to 7)). [12] A copolymer as described in [10] or [11], wherein Xb in the above formula (2) or (2') in the aforementioned compound ( ^b ) represents a divalent organic group (preferably an alkylene group such as methylene) or ^Yb is unbonded. [13] A copolymer as described in any one of [1] to [12], wherein the ratio of the aforementioned structural unit (B) in the copolymer is 5 to 40 mol%, with a lower limit of 10 mol% or 15 mol%, and an upper limit of 35 mol% or 30 mol%. [14] A copolymer as described in any one of [1] to [13], wherein the aforementioned compound (c) is different from the aforementioned compound (b). [15] The copolymer as described in any one of [1] to [14], wherein the epoxy group in the compound (c) is a group bonded to an aliphatic alkyl group (aliphatic epoxy group), preferably a glycidyl group. [16] The copolymer as described in any one of [1] to [15], wherein the compound (c) is at least one selected from the group consisting of allyl glycidyl ether, glycidyl (meth)acrylate, 2-methyl glycidyl (meth)acrylate, 2-ethyl glycidyl (meth)acrylate, 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxypropyl (meth)acrylate, glycidyloxyphenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate glycidyl ether, and 4-hydroxybutyl (meth)acrylate glycidyl ether. [17] A copolymer as described in any one of [1] to [16], wherein the ratio of the structural unit (C) in the copolymer is 10 to 60 mol%, with a lower limit of 15 mol% or an upper limit of 50 mol% or 35 mol%, relative to all the structural units constituting the copolymer. [18] A copolymer as described in any one of [1] to [17], comprising a structural unit (D) derived from at least one compound selected from the group consisting of (d1) to (d4) below. (d1) Styrene which may be substituted by an alkyl group (d2) N-substituted cis-butylene diimide (d3) N-vinyl compound (d4) An unsaturated carboxylic acid derivative represented by the above formula (4) (wherein R ^1d represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. R ^2d represents a monovalent organic group. ^Xd represents a heteroatom) [19] A copolymer as described in [18], which is obtained by subjecting a copolymer comprising the above structural unit (A), the above structural unit (B) and the above structural unit (D) to an addition reaction with the above compound (c). [20] A copolymer as described in [18] or [19], wherein the ratio of the above structural unit (D) in the copolymer is 0 to 50 mol % relative to all structural units constituting the copolymer, with a lower limit of 1 mol % or an upper limit of 35 mol %. [21] A copolymer as described in any one of [1] to [20], wherein when the copolymer comprises structural unit (A), structural unit (B) and structural unit (C) but does not comprise structural unit (D), the total amount of structural units (A) to (C) relative to all structural units constituting the copolymer is 90 mol% or more, 95 mol% or more, 99 mol% or more, or substantially 100 mol%; and when the copolymer comprises structural unit (A), structural unit (B), structural unit (C) and structural unit (D), the total amount of structural units (A) to (D) relative to all structural units constituting the copolymer is 90 mol% or more, 95 mol% or more, 99 mol% or more, or substantially 100 mol%. [22] A copolymer as described in any one of [1] to [21], wherein the weight average molecular weight (Mw) is 5,000 to 70,000 or 7,000 to 20,000, and the molecular weight distribution (ratio of weight average molecular weight to number average molecular weight: Mw/Mn) is 3.5 or less (e.g., 1.1 to 3.5), or 2.5 or less (1.1 to 2.5). [23] A copolymer as described in any one of [1] to [22], wherein the acid value is 30 to 120 mgKOH/g or 40 to 100 mgKOH/g. [24] A curable resin composition comprising the copolymer as described in any one of [1] to [23]. [25] A curable resin composition comprising the copolymer as described in [24], further comprising a polyfunctional vinyl compound, a polyfunctional thiol compound, or a polyfunctional epoxy compound. [26] The curable resin composition as described in [24] or [25], further comprising a photopolymerization initiator. [27] The curable resin composition as described in any one of [24] to [26], further comprising a colored material. [28] The curable resin composition as described in any one of [24] to [27], wherein the content of the copolymer in the curable resin composition is 3 to 40 weight %, and the content of the copolymer relative to the total amount of curable compounds contained in the curable resin composition is 20 weight % or more, 30 weight % or more, 40 weight % or more, or 50 weight % or more. [29] A cured product, which is a cured product of the curable resin composition as described in any one of [24] to [28]. [30] A color filter, which is a cured product of the curable resin composition described in any one of [24] to [28]. [31] A method for producing a copolymer, characterized in that a compound (a) represented by the above formula (1) (wherein R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms, R ^2a represents a divalent organic group, and X ^a represents a heteroatom) and an epoxy-containing polymerizable unsaturated compound (b) are copolymerized, and then the epoxy group of the epoxy-containing polymerizable unsaturated compound (c) is added to a part of the carboxyl groups of the obtained copolymer.

Claims (12)

A copolymer comprising a copolymer derived from the following formula (1): (wherein, R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms; R ^2a represents a divalent organic group; X ^a represents a heteroatom) A copolymer of a structural unit (A) of a compound (a) represented by the aforementioned formula; a structural unit (B) derived from a polymerizable unsaturated compound (b) containing an epoxy group; and a structural unit (C) derived from an addition reaction product of a compound (a) represented by the aforementioned formula (1) and a polymerizable unsaturated compound (c) containing an epoxy group, and having a carboxyl group derived from the compound (a) represented by the aforementioned formula (1); an epoxy group derived from the aforementioned polymerizable unsaturated compound (b) containing an epoxy group; and a polymerizable unsaturated group derived from the aforementioned polymerizable unsaturated compound (c) containing an epoxy group. The copolymer as described in claim 1, wherein the epoxy group of the aforementioned compound (b) is an alicyclic epoxy group. The copolymer as claimed in claim 1 or 2, wherein the epoxy group of the compound (b) is a monocyclic or bicyclic alicyclic epoxy group. The copolymer as described in claim 1 or 2, wherein in the aforementioned compound (c), the epoxy group is bonded to the aliphatic hydrocarbon group. The copolymer as described in claim 1 or 2, wherein in the aforementioned compound (a), R ^2a in formula (1) represents a divalent organic group containing an ester bond. The copolymer as claimed in claim 1 or 2, further comprising a structural unit (D) derived from at least one compound selected from the group consisting of the following (d1) to (d4): (d1) styrene which may be substituted by an alkyl group; (d2) N-substituted cis-butylenediimide; (d3) N-vinyl compound; (d4) the following formula (4) [Chemical Formula 2] (wherein R ^1d represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms; R ^2d represents a monovalent organic group; X ^d represents a heteroatom) an unsaturated carboxylic acid derivative represented by A curable resin composition comprising the copolymer as described in claim 1 or 2. The curable resin composition as described in claim 7 further contains a photopolymerization initiator. The curable resin composition as described in claim 7 further contains a colored material. A cured product, which is a cured product of the curable resin composition as described in claim 7. A color filter, which is a cured product of the curable resin composition as described in claim 9. A method for producing a copolymer, characterized in that the following formula (1) [chemical formula 3] (wherein R ^1a represents a hydrogen atom or an alkyl group having 1 to 7 carbon atoms; R ^2a represents a divalent organic group; X ^a represents a heteroatom) and a polymerizable unsaturated compound (b) containing an epoxy group are copolymerized, and then the epoxy group of the polymerizable unsaturated compound (c) containing an epoxy group is added to a part of the carboxyl groups of the obtained copolymer.