Copolymer and Method for Manufacturing the Copolymer

Abstract

The present invention aims to provide a resin composition that exhibits good developability and excellent storage stability when used as a photosensitive material, and a cured product with excellent solvent resistance even when cured at low temperatures; a copolymer useful for preparing this resin composition; and a method for manufacturing the copolymer. The copolymer is defined as containing structural units (a) having a group shown in formula (1) or (2), structural units (b) having hydroxyl groups, and structural units (c) having acid groups, and having a glass transition temperature of 30°C or below.

Description

[Technical Field]

[0001] This invention relates to copolymers, resin compositions, color filters, image display elements, and methods for manufacturing copolymers. [Previous Technology]

[0002] Generally speaking, in organic electroluminescent (EL) display devices (especially WRGB type combining white light-emitting organic EL and color filter), image display elements such as liquid crystal display elements, integrated circuit elements, solid-state imaging elements, etc., film and fine patterns such as color filter, black matrix, color filter protective film, light spacer, liquid crystal alignment protrusion, or microlens, touch panel insulating film, etc.

[0003] In recent years, with the increasing flexibility and wearability of displays, there has been a shift in substrate materials from glass to organic materials such as resin. Organic materials have lower heat resistance compared to glass. Therefore, in components formed by thermosetting resin compositions on a substrate, the temperature at which the resin composition is thermosettized is desired to be lower, depending on the heat resistance of the substrate made of organic materials. For example, color filters were conventionally formed by thermosetting the resin composition on a substrate at a temperature of 210-230°C. However, when forming color filters on a flexible substrate made of resin, due to the poor heat resistance of the substrate, it is required to thermoset the resin composition at a temperature of 80-150°C.

[0004] In particular, in order to improve color reproduction, there is a tendency to increase the content of colorants in the resin composition in color filters used in organic EL display devices. Generally speaking, resin compositions containing a large amount of colorants are difficult to photocur. Therefore, it is more important to cure the resin composition of color filters used in organic EL display devices by thermal cross-linking. Therefore, in particular, the need to improve the thermosetting properties at low temperatures is increasing in the resin composition of color filters used in organic EL display devices.

[0005] Conventionally, regarding resin compositions used as materials for color filters, for example, Patent Document 1 and Patent Document 2 have been disclosed. Patent Document 1 discloses a photosensitive coloring composition containing the following (a) to (e): (a) a polymerization initiator in methanol with an absorption coefficient of 1.0 × 10³ mL / gcm or higher at 365 nm, (b) a polymerization initiator in methanol with an absorption coefficient of 1.0 × 10² mL / gcm or lower at 365 nm and an absorption coefficient of 1.0 × 10³ mL / gcm or higher at 254 nm, (c) a compound having unsaturated double bonds, (d) an alkali-soluble resin, and (e) a colorant. Patent Document 2 discloses a photosensitive composition for color filters containing a compound comprising a furanyl group, a compound comprising a photopolymerizable functional group, a photopolymerization initiator, and a colorant. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2015-041058 [Patent Document 2] Japanese Patent Application Publication No. 2017-194662 [Summary of the Invention]

[0007] [The problem the invention aims to solve]

[0008] However, conventional resin compositions have not yielded curables that exhibit good developability and storage stability when used as photosensitive materials, and also possess excellent solvent resistance when cured at low temperatures. The present invention addresses these issues, and its object is to provide a resin composition, a copolymer useful for formulating this resin composition, and a method for manufacturing the copolymer. This resin composition exhibits good developability and excellent storage stability when used as a photosensitive material, and a curable with excellent solvent resistance can be obtained even when cured at low temperatures. Furthermore, the present invention aims to provide a color filter and an image display element having the color filter, wherein the color filter has a colored pattern formed from a curable of a resin composition that exhibits good developability and excellent solvent resistance even when cured at low temperatures. [Means for Solving the Problem]

[0009] The present invention comprises the following states. [1] A copolymer characterized by containing structural units (a) having a group of the following formula (1) or the following formula (2), structural units (b) having hydroxyl groups, and structural units (c) having acid groups, wherein the glass transition temperature is below 30°C.

[0010] (In formula (1), R1 and R2 are independent and represent alkyl groups with 1 to 10 carbon atoms. * indicates the linking site).

[0011] (In formula (2), R3 represents an alkyl group with 1 to 10 carbon atoms. * indicates a linking site).

[0012] [2] The copolymer described in [1], wherein the aforementioned structural unit (b) is a structural unit derived from hydroxyalkyl (meth)acrylate. [3] The copolymer described in [1] or [2], wherein the aforementioned structural unit (c) is a structural unit derived from unsaturated carboxylic acids. [4] The copolymer described in any one of [1] to [3], wherein the aforementioned structural unit (a) is a structural unit derived from a compound having a group and (meth)acryloxy group as shown in the aforementioned formula (1) or the aforementioned formula (2).

[0013] [5] The copolymer described in any one of [1] to [4] contains 1 to 40 mol% of the aforementioned structural unit (a), 1 to 60 mol% of the aforementioned structural unit (b), and 1 to 60 mol% of the aforementioned structural unit (c). [6] The copolymer described in any one of [1] to [5] has a mol ratio of the total amount of ester groups contained in the base represented by the aforementioned formula (1) or formula (2) to the total amount of hydroxyl groups contained in the aforementioned structural unit (b) of 10:90 to 90:10. [7] The copolymer described in any one of [1] to [6] has a weight average molecular weight of 1,000 to 50,000.

[0014] [8] A resin composition characterized by containing a copolymer (A) as described in any one of [1] to [7] and a solvent (B), wherein the solvent (B) comprises a hydroxyl-containing solvent. [9] Further containing a reactive diluent (C) and a photopolymerization initiator (D), the resin composition described in [8].

[10] Further containing a colorant (E), the resin composition described in [9].

[0015]

[11] The resin composition described in

[10] contains, with respect to 100 parts by mass of the copolymer (A) and the reactive diluent (C), 10 to 90 parts by mass of the copolymer (A), 30 to 1000 parts by mass of the solvent (B), 10 to 90 parts by mass of the reactive diluent (C), 0.1 to 30 parts by mass of the photopolymerization initiator (D), and 3 to 80 parts by mass of the colorant (E).

[0016]

[12] A color filter, characterized in that it has a colored pattern formed from a hardened resin composition as described in

[10] or

[11] .

[13] An image display element, characterized in that it has a color filter as described in

[12] .

[0017]

[14] A method for manufacturing a copolymer, characterized by comprising the following steps (I) to (III): a solvent heating step (I) of heating solvent (B-1) to 60 to 90°C and preparing the heated solvent (B-1h); a dropwise polymerization step (II) of dissolving monomers (ma) having the groups shown in formula (1) or formula (2) below, hydroxyl-containing monomers (mb) and acid-containing monomers (mc) in solvent (B-2) to form a monomer solution, and simultaneously dropping a polymerization initiator solution formed by dissolving a polymerization initiator in the aforementioned solvent (B-2) to the aforementioned solvent (B-1h) to form a mixed solution; and a post-polymerization step (III) of stirring the aforementioned mixed solution while reacting it at 60 to 90°C for 1 to 5 hours; either or both of the aforementioned solvent (B-1) and the aforementioned solvent (B-2) contain a hydroxyl-containing solvent.

[0018] (In formula (1), R1 and R2 are independent and represent alkyl groups with 1 to 10 carbon atoms. * indicates the linking site).

[0019] (In formula (2), R3 represents an alkyl group with 1 to 10 carbon atoms. * indicates a linking site).

[0020]

[15] In the method for manufacturing the copolymer as described in

[14] , in the aforementioned solvent heating step (I), a chain transfer agent is added to the aforementioned solvent (B-1) and then the temperature is increased. [Effects of the Invention]

[0021] According to the present invention, a resin composition, a copolymer useful for modulating the resin composition, and a method for manufacturing the copolymer can be provided. The resin composition exhibits good alkaline developability and excellent storage stability when used as a photosensitive material, and a cured product with excellent solvent resistance can be obtained even when cured at low temperatures. Furthermore, according to the present invention, a color filter and a color filter having the same can be provided. The color filter has a colored pattern formed from a cured product of a resin composition with good developability and excellent solvent resistance even when cured at low temperatures.

Implementation Method

[0022] Hereinafter, the copolymer, the method for manufacturing the copolymer, the resin composition, the color filter, and the image display element of the present invention will be described in detail. However, the present invention is not limited to the embodiments shown below.

[0023] Furthermore, the designation (meth)acrylate in this specification means either acrylate or methacrylate. Also, the designation (meth)acrylic acid means either acrylic acid or methacrylic acid.

[0024] <Copolymer (A)> The copolymer (A) of this embodiment contains a structural unit (a) having a base as shown in the following formula (1) or the following formula (2) (hereinafter, it is also referred to as "structural unit (a)"), a structural unit (b) having a hydroxyl group (hereinafter, it is also referred to as "structural unit (b)"), and a structural unit (c) having an acid group (hereinafter, it is also referred to as "structural unit (c)").

[0025] (In formula (1), R1 and R2 are independent and represent alkyl groups with 1 to 10 carbon atoms. * indicates the linking site).

[0026] (In formula (2), R3 represents an alkyl group with 1 to 10 carbon atoms. * indicates a linking site).

[0027] <Structural Unit (a)> Structural unit (a) is a structural unit derived from a monomer (ma) (hereinafter referred to simply as "monomer (ma)") having a base as shown in formula (1) or formula (2) above. The base of structural unit (a) contained in copolymer (A) as shown in formula (1) or formula (2) above is subjected to ester exchange with the hydroxyl group of structural unit (b) by thermosetting the resin composition containing copolymer (A), thereby generating a cross-linked structure. Therefore, the resin composition containing copolymer (A) can obtain a cured film with excellent solvent resistance even when cured at a low temperature of 50°C to 150°C.

[0028] In the above formula (1), R1 and R2 are each independent and are alkyl groups having 1 to 10 carbon atoms. It is preferable that R1 and R2 are each independent and are alkyl groups having 2 to 6 carbon atoms, and even more preferable that are alkyl groups having 2 to 3 carbon atoms. It is best if both R1 and R2 are ethyl groups having 2 carbon atoms. When R1 and R2 are ethyl groups, if the resin composition containing copolymer (A) is thermocured, R1 and R2 will undergo ester exchange with the hydroxyl group of structural unit (b) to generate ethanol. The ethanol generated during the thermocure of the resin composition can be easily evaporated and removed by heating used to thermocure the resin composition, which is preferable.

[0029] Furthermore, R3 in the above formula (2) is an alkyl group having 1 to 10 carbon atoms. It is preferable that R3 is an alkyl group having 2 to 6 carbon atoms, more preferably an alkyl group having 2 to 3 carbon atoms, and even more preferably an ethyl group having 2 carbon atoms. When R3 is an ethyl group, if the resin composition containing the copolymer (A) is thermocured, R3 undergoes transesterification with the hydroxyl group of the structural unit (b) to generate ethanol. The ethanol generated during the thermocure of the resin composition can be easily evaporated and removed by heating used to thermocure the resin composition, which is preferable.

[0030] The monomer (ma) providing the structural unit (a) is not particularly limited as long as it is a compound that can copolymerize with the hydroxyl-containing monomer (mb) and the acid-containing monomer (mc) described later. As a monomer (ma), for example, from the viewpoint of reactivity when synthesizing copolymer (A), a monomer having a group and an ethylene unsaturated bond as shown in formula (1) or formula (2) above can be used. Specifically, examples of groups having an ethylene unsaturated bond are vinyl and (meth)acrylic acid groups.

[0031] Examples of monomers (ma) having the group shown in formula (1) or formula (2) above and an ethylene unsaturated bond include isocyanate compounds containing ethylene unsaturated groups reacting with malonate diesters or acetylacetate. These monomers (ma) can be used alone or in combination of two or more.

[0032] The isocyanate compound containing an ethylene unsaturated group that generates the monomer (ma) is preferably a compound represented by the following formula (3).

[0033] (In formula (3), R4 represents a hydrogen atom or a methyl group. R5 represents -CO-, -COOR6- (here, R6 is an alkyl group with 1 to 6 carbon atoms) or -COO-R7O-CONH-R8- (here, R7 is an alkyl group with 2 to 6 carbon atoms; R8 is an alkyl group with 2 to 12 carbon atoms or an aryl group with 6 to 12 carbon atoms that may have substituents)).

[0034] In formula (3), R4 represents a hydrogen atom or a methyl group. In formula (3), R5 represents -CO-, -COOR6-, or -COO-R7O-CONH-R8-. Here, R6 is an alkyl group having 1 to 6 carbon atoms. R7 is an alkyl group having 2 to 6 carbon atoms. Also, R8 is an alkyl group having 2 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, which may have substituents. Among these, -COOR6- is preferred for R5 in formula (3). When R5 is -COOR6-, R6 is preferably an alkyl group having 1 to 4 carbon atoms.

[0035] Specifically, the isocyanate compound containing an ethylene unsaturated group as shown in the above formula (3) can be 2-isocyanoethyl (meth) acrylate, 2-isocyanopropyl (meth) acrylate, 3-isocyanopropyl (meth) acrylate, 2-isocyano-1-methylethyl (meth) acrylate, 2-isocyano-1,1-dimethylethyl (meth) acrylate, 4-isocyanocyclohexyl (meth) acrylate, (meth)acrylic acid isocyanate, etc.

[0036] Furthermore, as the isocyanate compound containing an ethylene-unsaturated group as shown in formula (3) above, the product of the reaction of 2-hydroxyalkyl (meth)acrylate with a diisocyanate compound in equal moles (1 mole: 1 mole) can also be used. As the alkyl group contained in the above-mentioned 2-hydroxyalkyl (meth)acrylate, ethyl or n-propyl is preferred, with ethyl being more preferred. Examples of the above-mentioned diisocyanate compound include hexamethylene diisocyanate, 2,4-(or 2,6-)toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 3,5,5-trimethyl-3-isocyanomethylcyclohexyl isocyanate (IPDI), m-(or p-)xylene diisocyanate, 1,3-(or 1,4-)bis(isocyanomethyl)cyclohexane, lysine diisocyanate, etc.

[0037] Among these isocyanate compounds containing vinyl unsaturated groups, 2-isocyanoethyl (meth)acrylate, 2-isocyanopropyl (meth)acrylate, 3-isocyanopropyl (meth)acrylate, 2-isocyano-1-methylethyl (meth)acrylate, 2-isocyano-1,1-dimethylethyl (meth)acrylate, 4-isocyanocyclohexyl (meth)acrylate, and (meth)acrylic acid isocyanate are preferred, with 2-isocyanoethyl (meth)acrylate and 2-isocyanopropyl (meth)acrylate being more preferred. These isocyanate compounds containing vinyl unsaturated groups can be used alone or in combination of two or more.

[0038] Examples of malonate diesters that react with isocyanate compounds containing vinyl unsaturated groups include dimethyl malonate, diethyl malonate, di(n-propyl malonate), and di(i-propyl malonate). From the perspectives of ease of acquisition, cost, and quality, diethyl malonate or dimethyl malonate is preferred. Examples of acetylacetic acid esters that react with isocyanate compounds containing vinyl unsaturated groups include methyl acetylacetic acid and ethyl acetate.

[0039] The reaction of isocyanate compounds containing vinyl unsaturated groups with malonate diesters or acetylacetate can be carried out regardless of the presence or absence of a solvent. When using a solvent for the above reaction, a solvent inert to the isocyanate group should be used. In the above reaction, organometallic salts such as tin, zinc, and lead, or tertiary amines can also be used as catalysts. Generally, the above reaction can be carried out at a temperature of -20 to 150°C, with 25 to 130°C being preferred. If the temperature of the above reaction is above -20°C, a sufficient reaction rate can be obtained. Furthermore, if the temperature of the above reaction is below 150°C, by using a raw material with C=C (double bond) for polymerization, gelation of the monomer (ma) that provides the structural unit (a) generated after the reaction can be prevented.

[0040] <Structural unit (b) with hydroxyl group> The copolymer (A) contains a structural unit (b) with hydroxyl group that does not have the group shown in formula (1) or formula (2) above, and has hydroxyl group. The structural unit (b) is a structural unit derived from a monomer (mb) with hydroxyl group (hereinafter, it is also referred to as "monomer (mb)") (except for those that conform to the aforementioned structural unit (a)). The hydroxyl group of the structural unit (b) contained in the copolymer (A) is transesterified with the group shown in formula (1) or formula (2) of the structural unit (a) by thermosetting the resin composition containing the copolymer (A) to generate a cross-linked structure.

[0041] The monomer (mb) providing structural unit (b) is not particularly limited as long as it has a polymerizable unsaturated bond and a hydroxyl group and does not have the group shown in formula (1) or formula (2) above. Examples of monomers (mb) include (meth)acrylate derivatives having hydroxyl groups. Specifically, examples of such monomers (mb) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, etc. These monomers (mb) can be used alone or in combination of two or more.

[0042] Among the monomers (mb), hydroxyalkyl (meth)acrylates are preferred from the viewpoints of reactivity during the synthesis of copolymer (A), low-temperature curing properties of the resin composition containing copolymer (A), and ease of acquisition. Among hydroxyalkyl (meth)acrylates, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred from the viewpoint of reducing the glass transition temperature of copolymer (A).

[0043] <Structural unit (c) with acid group> The structural unit (c) contained in the copolymer (A) does not have the group and hydroxyl group shown in formula (1) or formula (2) above, and has an acid group. The structural unit (c) is a structural unit derived from a monomer (mc) with an acid group (hereinafter, it is also referred to as "monomer (mc)") (except for those that conform to structural unit (a) and structural unit (b)). By having the copolymer (A) contain structural unit (c), the resin composition containing the copolymer (A) has good alkaline developability when used as a photosensitive material.

[0044] Examples of acid groups in the structural unit (c) include carboxyl groups, sulfonic acid groups, and phosphate groups. Among these acid groups, carboxyl groups are preferred in terms of ease of acquisition. The monomer (mc) providing the structural unit (c) is not particularly limited as long as it is a monomer having polymerizable unsaturated bonds and acid groups, and does not have the groups and hydroxyl groups shown in formula (1) or formula (2) above. Examples of monomers (mc) include unsaturated carboxylic acids or their anhydrides, unsaturated sulfonic acids, and unsaturated phosphonic acids.

[0045] Specifically, examples of unsaturated carboxylic acids or their anhydrides include (meth)acrylic acid, α-bromo(meth)acrylic acid, β-furanyl(meth)acrylic acid, crotonic acid, propynic acid, cinnamic acid, α-cyanocinonic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, itconic acid, itconic anhydride, citracic acid, citracic anhydride, etc.; unsaturated sulfonic acids such as 2-acrylamide-2-methylpropanesulfonic acid, tributylacrylamide sulfonic acid, p-styrene sulfonic acid, etc.; and unsaturated phosphonic acids such as vinylphosphonic acid; etc. These monomers (mc) can be used alone or in combination of two or more.

[0046] Among these monomers (mc), since they are readily available and the resin composition containing copolymer (A) has excellent alkali developability, unsaturated carboxylic acid is preferred, and (meth)acrylic acid is even better.

[0047] Here, the proportions of structural units (a), (b), and (c) contained in the copolymer (A) are described. While there is no particular limitation on the proportion of structural unit (a) contained in the copolymer (A), it is preferably 1 to 40 mol%, more preferably 5 to 30 mol%, and most preferably 10 to 20 mol%. While there is no particular limitation on the proportion of structural unit (b) contained in the copolymer (A), it is preferably 1 to 60 mol%, more preferably 10 to 50 mol%, and most preferably 20 to 40 mol%. While there is no particular limitation on the proportion of structural unit (c) contained in the copolymer (A), it is preferably 1 to 60 mol%, more preferably 10 to 50 mol%, and most preferably 15 to 40 mol.

[0048] Therefore, copolymer (A) preferably contains 1 to 40 mol% of structural unit (a), 1 to 60 mol% of structural unit (b), and 1 to 60 mol% of structural unit (c). In the copolymer (A) of this embodiment, if the ratio of structural unit (a) and structural unit (b) is 1 mol% or more, then by thermosetting the resin composition containing copolymer (A), the hydroxyl group of structural unit (b) undergoes transesterification with the group shown in formula (1) or formula (2) of structural unit (a). Therefore, a cross-linked structure is sufficiently generated. Therefore, a resin composition containing copolymer (A) containing 1 mol% or more of structural unit (a) and structural unit (b) can obtain a cured product with good solvent resistance even when thermoset at low temperature.

[0049] If the proportion of structural unit (a) in copolymer (A) is 40 mol% or less, the storage stability of the resin composition containing copolymer (A) becomes better. Furthermore, if the proportion of structural unit (a) is 40 mol% or less, it becomes easier to ensure the content of structural units (b) and (c). Therefore, it becomes easier to obtain the effects resulting from the presence of structural units (b) and (c).

[0050] Furthermore, if the proportion of structural unit (b) in copolymer (A) is 60 mol% or less, gelation during the polymerization reaction used to manufacture copolymer (A) can be prevented. Also, the cross-linking structure resulting from the transesterification reaction of structural unit (a) and structural unit (b) will not be excessively generated, resulting in better storage stability of the resin composition containing copolymer (A). Furthermore, if the proportion of structural unit (b) is 60 mol% or less, it becomes easier to ensure the content of structural unit (a) and structural unit (c). Therefore, it becomes easier to obtain the effects resulting from containing structural unit (a) and structural unit (c).

[0051] If the proportion of structural unit (c) in copolymer (A) is 1 mol% or more, the resin composition containing copolymer (A) becomes one with a sufficiently fast alkaline development speed. If the proportion of structural unit (c) in copolymer (A) is 60 mol% or less, the alkaline development speed of the resin composition containing copolymer (A) is moderately suppressed, thus making it easier to form delicate patterns. Furthermore, if the proportion of structural unit (c) in copolymer (A) is 60 mol% or less, it becomes easier to ensure the content of structural unit (a) and structural unit (b). Therefore, the resin composition containing copolymer (A) becomes easier to obtain a cured product with excellent solvent resistance, even when cured at low temperature.

[0052] In copolymer (A), the molar ratio ((a):(b)) of ester groups to hydroxyl groups is preferably 10:90 to 90:10, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. The molar ratio ((a):(b)) of ester groups to hydroxyl groups is the molar ratio of the total amount of ester groups in structural unit (a) as shown in formula (1) or formula (2) above to the total amount of hydroxyl groups contained in structural unit (b). If the molar ratio ((a):(b)) of ester groups to hydroxyl groups is within the above range, then by thermosetting the resin composition containing copolymer (A), a cross-linked structure resulting from the transesterification of hydroxyl groups in structural unit (b) with groups shown in formula (1) or formula (2) in structural unit (a) can be easily formed. Therefore, a cured product with better solvent resistance can be obtained.

[0053] The sum of the contents of structural unit (a) and structural unit (b) in copolymer (A) is preferably 20-80 mol%, more preferably 20-60 mol%, and even more preferably 25-40 mol%. If the sum of the contents of structural unit (a) and structural unit (b) is 20-80 mol%, the resin composition containing copolymer (A) has better storage stability, and a cured product with excellent solvent resistance can be obtained even when it is cured at low temperature. Furthermore, since the content of structural unit (c) is easily ensured, it is easy to obtain a resin composition with better alkali developability when used as a photosensitive material.

[0054] When a resin composition containing copolymer (A) includes a compound having hydroxyl groups as a reactive diluent (C) in addition to copolymer (A), it is preferable that the total amount of hydroxyl groups in the structural unit (b) contained in copolymer (A) is reduced by the amount of hydroxyl groups contained in reactive diluent (C). Specifically, the molar ratio of the total amount of ester groups in structural unit (a) of formula (1) or formula (2) above to the total amount of hydroxyl groups contained in the resin composition is preferably 10:90 to 90:10, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40. The total amount of hydroxyl groups contained in the resin composition is the sum of the hydroxyl groups in structural unit (b) and the hydroxyl groups contained in reactive diluent (C). If the molar ratio is within the above range, then by thermosetting the resin composition containing copolymer (A), a cross-linked structure is easily formed by the transesterification of the hydroxyl groups contained in the resin composition with the groups shown in formula (1) or formula (2) of the structural unit (a). Therefore, a cured product with better solvent resistance can be obtained.

[0055] <Other structural units (d)> The copolymer (A) of this embodiment may, as needed, contain other structural units (d) that can copolymerize with these structural units (a) to (c) (except for those that conform to structural units (a) to (c)).

[0056] The monomer (md) provided for other structural units (d) (hereinafter, also referred to as "monomer (md)") is preferably free of block oxidizing agents such as compounds having block isocyanate groups. If the copolymer (A) contains structural units derived from block oxidizing agents, the block oxidizing agent may sometimes remain in the cured product obtained by coating, exposing, developing, and then heating the resin composition containing it. The block oxidizing agent remaining in the cured product may have a detrimental effect on the insulation of the cured product or may degrade the solvent resistance of the cured product. Furthermore, the block oxidizing agent remaining in the cured product may cause dark spots caused by degassing in an image display element having a color filter with a color pattern formed from the cured product.

[0057] Specific examples of monomers (md) providing other structural units (d) include aromatic vinyl compounds, cyclic olefins having a norcamphene structure, dienes, (meth)acrylates, (meth)acrylates, (meth)acrylamide, vinyl compounds, unsaturated dicarboxylic acid diesters, monomaleimides, glycidyl (meth)acrylates, (meth)acrylamide benzene, (meth)acrylonitrile, acrolein, etc. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-vinyltoluene, p-vinyltoluene, o-chlorostyrene, m-chlorostyrene, methoxystyrene, p-nitrostyrene, p-cyanostyrene, p-acetylammonostyrene, etc. Examples of cyclic olefins with a nocamphene structure include nocamphene (bicyclo[2.2.1]hept-2-ene), 5-methylbicyclo[2.2.1]hept-2-ene, tetracyclo[4.4.0.12,5.17,10]dodec-3-ene, 8-ethyltetracyclo[4.4.0.12,5.17,10]dodec-3-ene, dicyclopentadiene, and tricyclo[5.2.1.02,6]dec-8-ene. Examples of dienes include tricyclic [4.4.0.12,5]undecyl-3-ene, tricyclic [6.2.1.01,8]undecyl-9-ene, tetracyclic [4.4.0.12,5.17,10.01,6]dodecyl-3-ene, 8-ethylidene tetracyclic [4.4.0.12,5.17,12]dodecyl-3-ene, and pentacyclic [6.5.1.13,6.02,7.09,13]pentadecanyl-4-ene. Examples of dienes include butadiene, isoprene, and chloroprene.Examples of (meth)acrylates include methacrylate, ethyl methacrylate, isopropyl methacrylate, tributyl methacrylate, pentyl methacrylate, benzyl methacrylate, isopentyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, dodecyl methacrylate, cyclohexyl methacrylate, methylcyclohexyl methacrylate, rosin methacrylate, norbornel methacrylate, 5-ethylnorbornel methacrylate, dicyclopentenyl methacrylate, dicyclopentyl methacrylate, dicyclopentenyloxyethyl acrylate, and isobornel methacrylate. Arandyl methacrylate, tetrahydrofurfuryl methacrylate, 1,1,1-trifluoroethyl methacrylate, perfluoroethyl methacrylate, perfluoro-n-propyl methacrylate, 3-(N,N-dimethylamino)propyl methacrylate, triphenylmethyl methacrylate, phenyl methacrylate, isopropylphenyl methacrylate, 4-phenoxyphenyl methacrylate, phenoxyethyl methacrylate, phenoxy polyethylene glycol methacrylate, nonylphenoxy polyethylene glycol mono(meth)acrylate, biphenoxyethyl methacrylate, naphthyl methacrylate, anthracene methacrylate, ethoxylated phenyl methacrylate, etc. Examples of (meth)acrylates include (meth)acrylate, N,N-dimethylamino(meth)acrylate, N,N-di-isopropylamino(meth)acrylate, and anthraceneamino(meth)acrylate. Examples of vinyl compounds include vinyl chloride, vinylidene dichloroisocyanurate, vinyl fluoride, vinylidene difluoroisocyanurate, N-vinylpyrrolidone, vinylpyridine, vinyl acetate, and vinyltoluene. Examples of unsaturated dicarboxylic acid diesters include diethyl citrate, diethyl maleate, diethyl fumarate, and diethyl itonate. Examples of monomaleimides include N-phenylmaleimide, N-cyclohexylmaleimide, N-laurylmaleimide, and N-(4-hydroxyphenyl)maleimide.

[0058] Among these, (meth)acrylate is preferred as the monomer (md). From the viewpoint of adjusting the glass transition temperature of the copolymer (A) to below 30°C, a homopolymer with a glass transition temperature of -20°C or below is preferred, and 2-ethylhexyl (meth)acrylate or 4-hydroxybutyl acrylate is particularly preferred. These monomers (md) can be used alone or in combination of two or more.

[0059] When copolymer (A) contains other structural units (d), there is no particular limitation on their proportion, but it is preferably more than 0 mol% to less than 80 mol%, more preferably 10 to 60 mol%, and most preferably 15 to 50 mol%. By containing other structural units (d), copolymer (A) can appropriately improve the solvent resistance and other properties of the cured resin composition containing copolymer (A). If the content of other structural units (d) is less than 80 mol%, it becomes easier to ensure the content of structural units (a) to (c), and the effect caused by including structural units (a) to (c) becomes significant.

[0060] (Weight Average Molecular Weight (Mw)) While there is no particular limitation on the weight average molecular weight of the polystyrene-converted copolymer (A), it is preferably 1,000 to 50,000, and more preferably 3,000 to 40,000. If the weight average molecular weight of copolymer (A) is 1,000 or higher, the alkaline developability of the resin composition containing copolymer (A) when used as a photosensitive material becomes good, making it difficult for pattern defects to occur after alkaline development. On the other hand, if the weight average molecular weight of copolymer (A) is 50,000 or lower, the development time when the resin composition containing copolymer (A) is used as a photosensitive material becomes appropriate, ensuring practicality.

[0061] (Glass transition temperature (Tg)) The glass transition temperature (Tg) of copolymer (A) is below 30°C, preferably below 20°C, and even more preferably below 0°C. If the glass transition temperature of copolymer (A) exceeds 30°C, it will have a negative impact on the curing properties at low temperatures. Therefore, the glass transition temperature of copolymer (A) is set to below 30°C. The glass transition temperature of copolymer (A) is preferably above -50°C, even more preferably above -40°C, and even more preferably above -30°C. If the glass transition temperature of copolymer (A) is above -50°C, then the resin composition containing copolymer (A) becomes a curing film with excellent heat resistance.

[0062] (Acid Value) The acid value (JIS K6901 5.3) of copolymer (A) can be appropriately selected. When the resin composition containing copolymer (A) is used as a photosensitive material, the acid value of copolymer (A) is preferably 20~300 KOH mg / g, more preferably 30~200 KOH mg / g. If the acid value of copolymer (A) is 20 KOH mg / g or higher, the alkaline developability of the resin composition containing copolymer (A) is good when used as a photosensitive material. On the other hand, if the acid value of copolymer (A) is 300 KOH mg / g or lower, when the resin composition containing copolymer (A) is used as a photosensitive material, the exposed part (photocured part) is difficult to dissolve in the alkaline developer, thus the pattern shape is good.

[0063] (Equivalent number of the groups shown in formula (1) or formula (2) above) Copolymer (A) contains the groups shown in formula (1) or formula (2) above in its molecule. The equivalent number of the groups shown in formula (1) or formula (2) above can be appropriately selected, but 300 to 6000 is preferred, and 1000 to 3000 is even more preferred. If the equivalent number of the groups shown in formula (1) or formula (2) above is 300 or more, when the hydroxyl groups in the resin composition containing copolymer (A) are sufficiently present, by thermosetting it, a cross-linked structure is fully formed due to the ester exchange between the hydroxyl groups in the resin composition and the groups shown in formula (1) or formula (2) in the structural unit (a). Therefore, a cured product with better solvent resistance can be obtained.

[0064] The equivalent number of the bases represented by formula (1) or formula (2) above in copolymer (A) is the mass of copolymer (A) per mole of the bases represented by formula (1) or formula (2) above contained in copolymer (A). The equivalent number of the bases represented by formula (1) or formula (2) above is obtained by dividing the mass of copolymer (A) by the number of moles of the bases represented by formula (1) or formula (2) above contained in copolymer (A) (g / mol). The equivalent number of the bases represented by formula (1) or formula (2) above is a theoretical value calculated from the feed amount of monomer (ma). In fact, as described in the manufacturing method of copolymer (A) below, the base shown in formula (1) or formula (2) above in copolymer (A) exists in copolymer (A) in a state in which a portion of it undergoes transesterification with the hydroxyl group derived from monomer (mb), or the hydroxyl group of a hydroxyl-containing solvent that can be used as a solvent (B-1) and / or solvent (B-2).

[0065] <Method for Manufacturing Copolymer (A)> The copolymer (A) of this embodiment can be manufactured, for example, by sequentially performing the solvent heating step (I), drop polymerization step (II), and post-polymerization step (III) as described below. (Solvent Heating Step (I)) The solvent (B-1) is heated to 60~90°C, and the heated solvent (B-1h) is prepared. In the solvent heating step (I), the chain transfer agent described later can be added to the solvent (B-1) before heating. By adding the chain transfer agent to the solvent (B-1) before heating, the degree of polymerization of the copolymer (A) synthesized in the drop polymerization step (II) and the post-polymerization step (III) can be controlled. The concentration of the chain transfer agent in the solvent (B-1) can be, for example, set to 0.1~10% by mass, without particular limitation.

[0066] (Droplet polymerization step (II)) While stirring the heated solvent (B-1h), a polymerization initiator solution is dropped into the heated solvent (B-1h) along with the monomer solution to form a mixed solution for droplet polymerization. The monomer solution is prepared by dissolving a monomer (ma) having a group shown in formula (1) or formula (2) above, a hydroxyl-containing monomer (mb), an acid-containing monomer (mc), and a monomer (md) as needed in solvent (B-2). The polymerization initiator solution is prepared by dissolving a polymerization initiator in solvent (B-2). In the method for manufacturing copolymer (A) of this embodiment, either or both of solvent (B-1) and solvent (B-2) contain a hydroxyl-containing solvent.

[0067] In the submerged polymerization step (II), the chain transfer agent solution described later may also be added dropwise instead of the chain transfer agent that may be added in the solvent heating step (I). The chain transfer agent solution is prepared by dissolving the chain transfer agent in the solvent (B-2). Alternatively, in the solvent heating step (I), a portion of the chain transfer agent used in the manufacture of copolymer (A) may be added to the solvent (B-1) and heated. In the submerged polymerization step (II), the chain transfer agent solution obtained by dissolving the remaining portion obtained by removing a portion of the chain transfer agent used in the solvent (B-2) may be added dropwise to the heated solvent (B-1h).

[0068] (Post-polymerization step (III)) After the monomer solution and polymerization initiator solution are dripped, the aforementioned mixed solution is stirred and then reacted at 60~90°C for 1~5 hours.

[0069] "Solvent (B-1)" The solvent (B-1) used in the solvent heating step (I) may be a solvent containing only hydroxyl groups, a solvent that does not contain only hydroxyl groups, or both a solvent containing hydroxyl groups and a solvent that does not contain hydroxyl groups. Solvent (B-1) is preferably a solvent containing hydroxyl groups, and is even more preferably a solvent containing only hydroxyl groups.

[0070] Examples of solvents containing hydroxyl groups include (poly)alkyl glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether; hydroxyl-containing carboxylic acid esters such as methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxypropionate, ethyl hydroxyacetate, and methyl 2-hydroxy-3-methylbutyrate; 3-methoxy-1-butanol; and diethylene glycol.

[0071] Among these hydroxyl-containing solvents, primary and / or secondary alcohol solvents and ether solvents are preferred because they are highly effective in inhibiting the transesterification reaction between the ester group derived from monomer (ma) and the hydroxyl group derived from monomer (mb) in the dropwise polymerization step (II) and / or post-polymerization step (III). Propylene glycol monomethyl ether, ethylene glycol monomethyl ether, and 3-methoxy-1-butanol are particularly preferred. These hydroxyl-containing solvents can be used alone or in combination of two or more.

[0072] Examples of solvents that do not contain hydroxyl groups include (poly)alkylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and tetrahydrofuran; ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, and 3-heptanone; methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl ethoxylate, and 3-methyl-3-methoxybutyl ether. Esters such as acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, n-butyl acetate, i-propyl acetate, i-butyl acetate, n-pentyl acetate, i-pentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, ethyl butyrate, n-propyl butyrate, methyl acetoacetate, ethyl acetoacetate, 2-side-oxyethyl butyrate, etc.; aromatic hydrocarbons such as toluene and xylene; carboxylic amines such as N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide, etc.

[0073] Among hydroxyl-free solvents, ether-based solvents are preferred from the perspectives of ease of acquisition, cost, and quality, with propylene glycol monomethyl ether acetate and diethylene glycol methyl ethyl ether being even better. These hydroxyl-free solvents can be used alone or in combination of two or more.

[0074] When the solvent (B-1) used in the solvent heating step (I) contains a hydroxyl-containing solvent, the proportion of the hydroxyl-containing solvent in the solvent (B-1) is preferably 10-100% by mass, more preferably 20-90% by mass, and even more preferably 40-80% by mass. If the proportion of the hydroxyl-containing solvent is 10% by mass or more, the effect of hindering the transesterification reaction between the ester groups derived from monomer (ma) and the hydroxyl groups derived from monomer (mb) can be sufficiently obtained in the droplet polymerization step (II) and / or the post-polymerization step (III). When the solvent (B-1) contains a solvent without hydroxyl groups, the residual amount of ester groups derived from monomer (ma) in the copolymer (A) can be increased, thereby increasing the amount of crosslinking reaction caused by the transesterification reaction between the ester groups derived from monomer (ma) and the hydroxyl groups derived from monomer (mb) during the curing of the resin composition.

[0075] "Temperature of Solvent and Mixed Solution" In the manufacturing method of this embodiment, in the solvent heating step (I), solvent (B-1) is added to the reaction vessel and the temperature is raised to 60~90°C. Furthermore, in the dropwise polymerization step (II) and the post-polymerization step (III), the mixed solution is stirred while reacting at 60~90°C for 1~5 hours. The temperature of the solvent (B-1h) in the solvent heating step (I) may be the same as or different from the temperature of the mixed solution in the dropwise polymerization step (II) and the post-polymerization step (III).

[0076] In this embodiment, since the temperature of the solvent (B-1h) in the solvent heating step (I) is above 60°C, and the temperature of the mixed solution in the dropwise polymerization step (II) and the post-polymerization step (III) is above 60°C, the polymerization reactions of monomers (ma) to (mc) and monomers (md) used as needed are fully carried out in the dropwise polymerization step (II) and the post-polymerization step (III).

[0077] Since the temperature of the solvent (B-1h) in the solvent heating step (I) is below 90°C, and the temperature of the mixed solution in the dropwise polymerization step (II) and the post-polymerization step (III) is below 90°C, the transesterification reaction between the ester group derived from monomer (ma) and the hydroxyl group derived from monomer (mb) can be suppressed in the dropwise polymerization step (II) and the post-polymerization step (III). Furthermore, if the above temperature is below 90°C, when an isocyanate compound containing an vinyl unsaturated group is used as the monomer (ma) in reaction with a malonate diester or acetic acid ester, the following effect can be obtained. That is, the dissociation of malonate diester or acetic acid ester from the group shown in formula (1) or formula (2) above to generate isocyanate groups can be prevented in the dropwise polymerization step (II) and the post-polymerization step (III). Therefore, it is possible to prevent the isocyanate group generated by the dissociation of the base shown in formula (1) or formula (2) above from reacting with the hydroxyl group derived from monomer (mb) or the acid group derived from monomer (mc) during the manufacturing process, thereby preventing the copolymer (A) from gelling.

[0078] In the dropwise polymerization step (II), the polymerization initiator solution and monomer solution are dropped dropwise into the solvent heated in the solvent heating step (I) to a temperature of 60-90°C (B-1h) to form a mixed solution for simultaneous polymerization. Alternatively, in the dropwise polymerization step (II), the chain transfer agent solution can be further dropped dropwise into the heated solvent (B-1h) to form a mixed solution containing the chain transfer agent.

[0079] In the dropwise polymerization step (II), it is preferable to drop the polymerization initiator solution and the monomer solution simultaneously into the heated solvent (B-1h). This allows for accurate control of the molecular weight of the copolymer (A) and prevents gelation of the copolymer (A) during manufacturing. In the dropwise polymerization step (II), when the chain transfer agent solution is dropped into the heated solvent (B-1h), it can also be dropped simultaneously with the polymerization initiator solution and the monomer solution. Alternatively, the chain transfer agent solution can be dropped before or after the polymerization initiator solution and the monomer solution.

[0080] The dripping rates of the polymerization initiator solution, monomer solution, and chain transfer agent solution can be appropriately determined based on the reaction scale, including the capacity of the reaction vessel, the solvent heated (B-1h), and the volumes of the polymerization initiator solution, monomer solution, and chain transfer agent solution. For example, when using a 1L reaction vessel, a dripping rate of 0.1~5mL / min is preferable. The dripping time of the polymerization initiator solution, monomer solution, and chain transfer agent solution can be, for example, set to 30 minutes to 1 hour. The dripping rates and dripping times of the polymerization initiator solution, monomer solution, and chain transfer agent solution can be different, or partially or entirely the same.

[0081] In this embodiment, the polymerization initiator solution, monomer solution, and chain transfer agent solution (if needed) are prepared separately. (Polymerization initiator solution) The polymerization initiator solution is prepared by dissolving the polymerization initiator in solvent (B-2). While there are no particular limitations on the polymerization initiator, examples include 2,2'-azobis(2,4-dimethylpentanonitrile), azobisisobutyronitrile, azobisisovalerate, benzoyl peroxide, and t-butylperoxy-2-ethylhexanoate. These polymerization initiators can be used alone or in combination of two or more.

[0082] The concentration of the polymerization initiator in the polymerization initiator solution is preferably such that a uniform concentration of the mixed solution can be easily obtained; for example, it can be set to 16-50% by mass, and there is no particular limitation. The amount of polymerization initiator solution used is preferably 0.5-20 parts by mass of the polymerization initiator contained in the polymerization initiator solution relative to 100 parts by mass of the total monomer feed, and more preferably 1.0-10 parts by mass. The total monomer feed mentioned above refers to the mass of monomer (ma) to monomer (md) in the monomer solution.

[0083] (Monomer Solution) The monomer solution is prepared by dissolving a monomer (ma) having a group shown in formula (1) or formula (2) above, a hydroxyl-containing monomer (mb), an acid-containing monomer (mc), and a monomer (md) as needed, in a solvent (B-2). As monomers (ma) to monomers (md), those exemplified in the section on copolymers (A) can be used.

[0084] The monomer solution can be prepared by dissolving each monomer (ma) to (md) separately in a solvent (B-2) and then mixing them, or by mixing monomers (ma) to (md) and then dissolving them in a solvent (B-2). The total concentration of monomers (ma) to (md) in the monomer solution is preferably such that a uniform concentration of the mixed solution can be easily obtained; for example, it can be set to 50 to 95% by mass, and there is no particular limitation.

[0085] There are no particular restrictions on the proportions of the monomers (ma) to (mc) used in the manufacture of copolymer (A), but it is preferable that monomer (ma) is 1 to 40 mol%, monomer (mb) is 1 to 60 mol%, and monomer (mc) is 1 to 60 mol%, monomer (ma) is 5 to 30 mol%, monomer (mb) is 10 to 50 mol%, and monomer (mc) is 10 to 50 mol%, and even more preferable that monomer (ma) is 10 to 20 mol%, monomer (mb) is 20 to 40 mol%, and monomer (mc) is 15 to 40 mol%.

[0086] When the copolymer (A) contains structural unit (d), the proportions of each monomer (ma) to (md) used in the manufacture of the copolymer (A) are not particularly limited, but it is preferable that the monomer (ma) is 1 to 40 mol%, the monomer (mb) is 1 to 60 mol%, the monomer (mc) is 1 to 60 mol%, and the monomer (md) is more than 0 to 80 mol%. It is even better that the monomer (ma) is 5 to 30 mol%, the monomer (mb) is 10 to 50 mol%, the monomer (mc) is 10 to 50 mol%, and the monomer (md) is 10 to 60 mol%. It is even more preferable that the monomer (ma) is 10 to 20 mol%, the monomer (mb) is 20 to 40 mol%, the monomer (mc) is 15 to 40 mol%, and the monomer (md) is 15 to 50 mol%.

[0087] (Chain Transfer Agent Solution) The chain transfer agent solution is prepared by dissolving the chain transfer agent in a solvent (B-2). In the dropwise polymerization step (II), by adding the chain transfer agent solution, the degree of polymerization of the copolymer (A) synthesized in the subsequent polymerization step (III) can be controlled. Therefore, copolymers (A) with desired molecular weight ranges can be easily manufactured. While there are no particular limitations on the chain transfer agent, polyfunctional thiols are preferred, for example. Polyfunctional thiols are compounds having two or more thiol groups within their molecules.

[0088] While there are no particular limitations on polyfunctional thiols, examples include mercaptoacetic acid, 1,2-ethanedithiol, 1,4-bis(3-mercaptobutyroxyl)butane, tetraethylene glycol bis(3-mercaptopropionate), trimethylolethane benzo(3-mercaptobutyrate), trimethylolpropane benzo(3-mercaptobutyrate), trimethylolpropane benzo(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), pentaerythritol tetra(3-mercaptopropionate), 1,3,5-benzo(3-mercaptobutyroxylethyl)-1,3,5-tri-2,4,6(1H,3H,5H)-trione, benzo-[(3-mercaptopropyroxyl)-ethyl]-isocyanurate, dipentaerythritol thio(3-mercaptopropionate), etc.

[0089] Among the chain transfer agents mentioned above, from the viewpoints of ease of acquisition, cost, and quality, pentaerythritol tetrakis (3-mercaptobutyrate) and / or thioacetic acid and pentaerythritol tetrakis (3-mercaptopropionate) are preferred. The concentration of the chain transfer agent in the polymerization initiator solution is preferably such that a uniform concentration of the mixed solution can be easily obtained; for example, it can be set to 0.1 to 10% by mass, without particular limitation.

[0090] The amount of chain transfer agent solution used is preferably 0.5 to 20 parts by mass, and more preferably 1.0 to 10 parts by mass, relative to 100 parts by mass of the total monomer feed. The total monomer feed refers to the mass of monomers (ma) to (md) in the monomer solution. By setting the amount of chain transfer agent solution used within the above range, copolymers (A) with the desired molecular weight range can be easily produced in the post-polymerization step (III).

[0091] "Solvent (B-2)" The solvent (B-2) used in the droplet polymerization step (II) can be the same as the solvent (B-1) used in the solvent heating step (I). Like solvent (B-1), solvent (B-2) can be a solvent containing only hydroxyl groups, a solvent without hydroxyl groups, or a combination of both. Solvent (B-2) is preferably a solvent containing hydroxyl groups, and even more preferably a solvent containing only hydroxyl groups.

[0092] In the method for manufacturing the copolymer (A) of this embodiment, either or both of the solvent (B-1) and solvent (B-2) contain a hydroxyl-containing solvent. Therefore, when the solvent (B-1) used in the solvent heating step (I) does not contain a hydroxyl-containing solvent, the solvent (B-2) used in the dropwise polymerization step (II) contains a hydroxyl-containing solvent.

[0093] The proportion of hydroxyl-containing solvent in the combined amount of solvent (B-1) used in solvent heating step (I) and solvent (B-2) used in drop polymerization step (II) is preferably 10-100% by mass, more preferably 20-90% by mass, and even more preferably 40-80% by mass. If the proportion of hydroxyl-containing solvent is 10% by mass or more, the effect of inhibiting the transesterification reaction between ester groups derived from monomer (ma) and hydroxyl groups derived from monomer (mb) can be sufficiently obtained in drop polymerization step (II) and / or post-polymerization step (III). When one or both of solvent (B-1) and solvent (B-2) contain a solvent without hydroxyl groups, if the proportion of hydroxyl-containing solvent is 90% by mass or less, the residual amount of ester groups derived from monomer (ma) in copolymer (A) can be increased, thereby increasing the amount of crosslinking reaction caused by the transesterification reaction between ester groups derived from monomer (ma) and hydroxyl groups derived from monomer (mb) during the curing of the resin composition.

[0094] In the manufacturing method of this embodiment, since the solvent (B-1) used in the solvent heating step (I) and / or the solvent (B-2) used in the droplet polymerization step (II) contains a hydroxyl-containing solvent, the following effects can be obtained. In a mixed solution containing a hydroxyl-containing solvent, if the monomer (ma), (mb), (mc), or the monomer (md) to be used as needed is polymerized at 60~90°C, the ester group derived from the monomer (ma) readily undergoes an ester exchange reaction with the hydroxyl group present in the hydroxyl-containing solvent. Therefore, in the droplet polymerization step (II) and / or the post-polymerization step (III), a portion of the ester group of the monomer (ma) represented by the above formula (1) or above formula (2) undergoes an ester exchange reaction with the hydroxyl group present in the hydroxyl-containing solvent.

[0095] If the ester group derived from the monomer (ma) undergoes an ester exchange reaction with the hydroxyl group of the solvent containing the hydroxyl group, an alcohol having a group (R1 and R2 in formula (1), or R3 in formula (2)) derived from the ester group of the monomer (ma) is generated in the mixed solution. Since this reaction is reversible, a portion of the generated alcohol undergoes an ester exchange reaction with the generated compound (reverse reaction) to generate the monomer (ma) and the solvent containing the hydroxyl group. Therefore, it is presumed that even if the ester group derived from the monomer (ma) undergoes an ester exchange reaction with the hydroxyl group of the solvent containing the hydroxyl group, the ester group derived from the monomer (ma) will remain adequately in the mixed solution.

[0096] When the monomer (ma) has the group shown in formula (1), for example, if R1 in formula (1) undergoes an ester exchange reaction with the hydroxyl group of a hydroxyl-containing solvent, the group formed by the reaction with R1 in formula (1) in the resulting compound becomes a steric barrier, and the ester exchange reaction between R2 in formula (1) and the hydroxyl group is unlikely to occur. Therefore, it is speculated that when the monomer (ma) has the group shown in formula (1), only a portion of the ester group of the monomer (ma) undergoes an ester exchange reaction with the hydroxyl group of a hydroxyl-containing solvent, and the ester group originating from the monomer (ma) is moderately retained.

[0097] Thus, in this embodiment, during the droplet polymerization step (II) and / or the post-polymerization step (III), since the ester groups derived from monomer (ma) undergo transesterification with the hydroxyl groups in the hydroxyl-containing solvent, the transesterification reaction between the ester groups derived from monomer (ma) and the hydroxyl groups derived from monomer (mb) is moderately hindered. Therefore, in the post-polymerization step (III), gelation of the copolymer (A) during manufacturing can be prevented. Furthermore, the storage stability of the resin composition containing copolymer (A) becomes good.

[0098] Furthermore, in this embodiment, by appropriately hindering the transesterification reaction in the drip polymerization step (II) and / or the post-polymerization step (III), the reduction of ester groups derived from monomer (ma) and hydroxyl groups derived from monomer (mb) can be prevented before the resin composition containing copolymer (A) is thermosetting. Therefore, copolymer (A) with an appropriate residual ester groups derived from monomer (ma) and hydroxyl groups derived from monomer (mb) can be obtained. Furthermore, the compound generated by the transesterification reaction between the ester groups derived from monomer (ma) and the hydroxyl groups in a hydroxyl-containing solvent generates a cross-linked structure through transesterification with monomer (mb). Therefore, by thermosetting the resin composition containing copolymer (A), a cross-linked structure resulting from the transesterification of ester groups derived from monomer (ma) and hydroxyl groups derived from monomer (mb) can be sufficiently generated, resulting in a cured product with good solvent resistance.

[0099] While there is no particular limitation on the amount of solvent (B-1) used in the solvent heating step (I) and solvent (B-2) used in the dropwise polymerization step (II), the combined amount of solvent (B-1) and solvent (B-2) is preferably 30 to 1,000 parts by mass, and more preferably 50 to 800 parts by mass, relative to 100 parts by mass of the total monomer feed (i.e., the mass of monomer (ma) to monomer (md) in the monomer solution). If the combined amount of solvent (B-1) and solvent (B-2) is less than 1,000 parts by mass relative to 100 parts by mass of the total monomer feed, the viscosity of the reaction solution containing copolymer (A) obtained in the subsequent polymerization step (III) becomes suitable. Furthermore, by setting the combined amount of solvent (B-1) and solvent (B-2) to 1,000 parts by mass or less, the decrease in molecular weight of the copolymer (A) obtained by chain transfer can be suppressed when the chain transfer agent solution is added dropwise in the dropwise polymerization step (II). Also, by setting the combined amount of solvent (B-1) and solvent (B-2) to 30 parts by mass or more relative to the total monomer feed amount of 100 parts by mass, abnormal polymerization reactions in the subsequent polymerization step (III) can be prevented, and the polymerization reaction can be carried out stably. As a result, gelation of the copolymer (A) during manufacturing can be prevented, and a colorless copolymer (A) can be obtained.

[0100] In the manufacturing method of this embodiment, in the post-polymerization step (III), the mixed solution obtained in the polymerization step (II) is added dropwise while stirring, and the mixture is reacted at 60-90°C for 1-5 hours. The reaction time in the post-polymerization step (III) can be set to 1-5 hours, preferably 1-4 hours, and more preferably 2-3 hours. If the reaction time is 1-5 hours, a copolymer (A) with an appropriate molecular weight can be produced with good yield.

[0101] The copolymer (A) of this embodiment contains structural units (a) having the base shown in formula (1) or formula (2) above, structural units (b) having hydroxyl groups, and structural units (c) having acid groups, and the glass transfer temperature is 30°C or below. Therefore, the resin composition of this embodiment containing copolymer (A) has good alkaline developability when used as a photosensitive material, and excellent storage stability. Even when it is cured at low temperature, a cured product with excellent solvent resistance can be obtained.

[0102] In the method for manufacturing the copolymer (A) of this embodiment, the solvent (B-1) used in the solvent heating step (I) and / or the solvent (B-2) used in the dropwise polymerization step (II) are solvents containing hydroxyl groups. In the solvent heating step (I), the solvent (B-1) is heated to 60-90°C, and in the subsequent polymerization step (III), the mixed solution is reacted at 60-90°C. Therefore, in the dropwise polymerization step (II) and / or the subsequent polymerization step (III), the transesterification reaction between the ester group derived from monomer (ma) and the hydroxyl group derived from monomer (mb) is moderately hindered. As a result, the copolymer (A) of this embodiment, which sufficiently contains structural units (a) having the base shown in formula (1) or formula (2) above and structural units (b) having hydroxyl groups, can be obtained.

[0103] In contrast, conventionally, when using solvents to polymerize copolymers, solvents that do not react with the monomers are selected. Therefore, in conventional techniques, when using solvents to polymerize copolymers, the monomers and solvents do not react. Therefore, conventional techniques do not assume the use of the reaction between monomers and solvents, and there is no method for controlling the properties of copolymers by utilizing the reaction between monomers and solvents.

[0104] <Resin Composition> Next, the resin composition of this embodiment will be described. The resin composition of this embodiment contains the copolymer (A) and solvent (B) of this embodiment. The resin composition of this embodiment may also contain a reactive diluent (C) and a photopolymerization initiator (D) in addition to the copolymer (A) and solvent (B). Such a resin composition is preferably used as a photosensitive resin composition. In addition to the copolymer (A) to the photopolymerization initiator (D), the resin composition of this embodiment may also contain a colorant (E). Such a resin composition is preferably used as a material for forming colored patterns such as color filters, black matrices, and black tube column separators.

[0105] (Solvent (B)) In the resin composition of this embodiment, solvent (B) includes a hydroxyl-containing solvent. Solvent (B) may be only a hydroxyl-containing solvent. In the resin composition of this embodiment, since solvent (B) includes a hydroxyl-containing solvent, the ester group of the structural unit (a) of copolymer (A) undergoes an ester exchange reaction with the hydroxyl group of the hydroxyl-containing solvent in solvent (B), which moderately hinders the ester exchange reaction between the ester group of structural unit (a) and the hydroxyl group of structural unit (b), thereby improving storage stability.

[0106] Regarding the hydroxyl-containing solvent used as solvent (B), there are no particular limitations as long as the solvent contains hydroxyl groups. The same solvents used in the steps of manufacturing copolymer (A) that can be used as solvents (B-1) and (B-2) can be used. For example, solvents that do not contain hydroxyl groups that can be used as solvent (B) that can be used in the steps of manufacturing copolymer (A) are the same solvents used as solvents (B-1) and (B-2).

[0107] The proportion of hydroxyl-containing solvent in solvent (B) can be set in the same way as the proportion of hydroxyl-containing solvent in solvent (B-1) used in the step of manufacturing copolymer (A). Solvent (B) can be the same as or different from solvent (B-1) and / or solvent (B-2) used in the step of manufacturing copolymer (A).

[0108] The resin composition of this embodiment can be manufactured by appropriately mixing copolymer (A) isolated from the reaction solution containing copolymer (A) obtained in polymerization step (III) after manufacturing copolymer (A) and solvent (B). Alternatively, the reaction solution containing copolymer (A) obtained during the manufacturing of copolymer (A) can be used directly as the resin composition of this embodiment. In this case, it is not necessary to isolate copolymer (A) from the reaction solution. Furthermore, when the reaction solution contains solvent (B-1) and / or solvent (B-2) used in the manufacturing of copolymer (A), solvent (B-1) and / or solvent (B-2) in the reaction solution can be used directly as solvent (B). Solvent (B) can also be added to the reaction solution as needed.

[0109] In the resin composition of this embodiment, the amounts of copolymer (A) and solvent (B) can be adjusted appropriately according to the intended use of the resin composition. For example, in the resin composition of this embodiment, it is preferable to contain 30 to 1,000 parts by mass of solvent (B) relative to 100 parts by mass of copolymer (A), and more preferably 50 to 800 parts by mass. If the content of solvent (B) is 30 parts by mass or more, the viscosity of the resin composition is appropriate. Furthermore, by setting the amount of solvent (B) to 30 parts by mass or more, abnormal polymerization reactions can be prevented, the hardening of the resin composition can be carried out stably, and coloring and gelation of the resin composition can be prevented. If the content of solvent (B) is 1,000 parts by mass or less, the viscosity of the resin composition can be controlled within an appropriate range.

[0110] (Reactive Diluent (C)) The reactive diluent (C) is included together with the photopolymerization initiator (D) as needed. The reactive diluent (C) is a compound having at least one polymerizable vinyl unsaturated group as a polymerizable functional group within its molecule. The reactive diluent (C) can be a monofunctional monomer or a polyfunctional monomer, with polyfunctional monomers having multiple polymerizable functional groups being preferred. By preparing a resin composition containing the reactive diluent (C), viscosity adjustment becomes easy. Furthermore, by preparing a resin composition containing the reactive diluent (C), the adhesion of the cured resin composition to the substrate may be improved, or the strength of the cured resin composition may be adjusted.

[0111] Examples of monofunctional monomers used as reactive diluents (C) include (meth)acrylamide, hydroxymethyl (meth)acrylamide, methoxymethyl (meth)acrylamide, ethoxymethyl (meth)acrylamide, propoxymethyl (meth)acrylamide, butoxymethoxymethyl (meth)acrylamide, meth (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2 - Phenoxy-2-hydroxypropyl (meth)acrylate, 2-(meth)acryloxy-2-hydroxypropyl phthalate, glyceryl mono(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, hemi(meth)acrylates of phthalic acid derivatives, etc. (meth)acrylates; aromatic vinyl compounds such as styrene, α-methylstyrene, α-chloromethylstyrene, vinyltoluene, etc.; carboxylic acid esters such as vinyl acetate, vinyl propionate, etc. These monofunctional monomers can be used alone or in combination of two or more.

[0112] Examples of multifunctional monomers used as reactive diluents (C) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 2,2-bis(4-(meth)propenyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)propenyloxypolyethoxyphenyl)propane, 2-hydroxy-3-(meth)propenyloxypropyl ( Methacrylates, ethylene glycol digoxypropyl ether di(meth)acrylates, diethylene glycol digoxypropyl ether di(meth)acrylates, digoxypropyl phthalate di(meth)acrylates, glycerol triacrylates, glycerol polygoxypropyl ether poly(meth)acrylates, urethane (meth)acrylates (i.e., toluene diisocyanate), trimethylhexamethylene diisocyanate and hexamethylene diisocyanate reacting with 2-hydroxyethyl (meth)acrylates, tri(hydroxyethyl)isocyanate tri(meth)acrylates and other (meth)acrylates; aromatic vinyl compounds such as divinylbenzene, diallyl phthalate, diallyl phenylphosphonate; dicarboxylic acid esters such as divinyl adipate; triallyl cyanate, methylene bis(meth)acrylamide, (meth)acrylamide methylene ether, condensates of polyols and N-hydroxymethyl (meth)acrylamide, etc. These multifunctional monomers can be used individually or in combination of two or more.

[0113] Among these monomers, from the viewpoint of improving the development morphology or curability of the resin composition, it is preferable to use a polyfunctional (meth)acrylate as the reactive diluent (C), and it is even more preferable to use one or more of the following: trimethylolpropane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0114] When the resin composition contains a reactive diluent (C), the following proportions of each component, relative to 100 parts by mass of the total mass of copolymer (A) and reactive diluent (C), are preferred: 10-90 parts by mass of copolymer (A), 30-1,000 parts by mass of solvent (B), and 10-90 parts by mass of reactive diluent (C); more preferably, 20-80 parts by mass of copolymer (A), 50-800 parts by mass of solvent (B), and 20-80 parts by mass of reactive diluent (C); and even more preferably, 30-75 parts by mass of copolymer (A), 100-700 parts by mass of solvent (B), and 25-70 parts by mass of reactive diluent (C). If the proportions of each component are within the above ranges, a resin composition with appropriate viscosity is obtained, suitable for use in various coatings, adhesives, and binders for printing inks.

[0115] (Photopolymerization Initiator (D)) While there are no particular limitations on the photopolymerization initiator (D), examples include benzoin-based products such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin butyl ether; acetophenone-based products such as 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4-(1-t-butyldioxy-1-methylethyl)acetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)butanone-1; and 2-methylanthraquinone, 2-pentylanthraquinone, and 2-t-butylanthraquinone. Anthraquinones such as quinones and 1-chloroanthraquinones; thioxanthones such as xanthraquinones, thioxanthones, 2,4-dimethylthioxanthones, 2,4-diisopropylthioxanthones, and 2-chlorothioxanthones; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as 4-(1-t-butyldioxy-1-methylethyl)benzophenone and 3,3',4,4'-tetra(t-butyldioxycarbonyl)benzophenone; acetylphosphine oxides; acetone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyloxime), etc. These photopolymerization initiators (D) can be used alone or in combination of two or more.

[0116] When the resin composition contains a photopolymerization initiator (D), its content is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, and even more preferably 1 to 15 parts by weight, relative to 100 parts by weight of the copolymer (A) and the reactive diluent (C).

[0117] (Coloring Agent (E)) Coloring agent (E) is included as needed. As a coloring agent (E), there are no particular limitations as long as it is dissolved or dispersed in solvent (B), such as dyes or pigments. Depending on the color of the cured product of the target resin composition, coloring agent (E) can be used alone or in combination with two or more. As a coloring agent (E), dyes can be used alone, pigments can be used alone, or a combination of dyes and pigments can be used.

[0118] As a dye, from the viewpoints of solubility in solvent (B) and alkaline developer, interaction with other components in the resin composition, and heat resistance, it is preferable to use acid dyes with acidic groups such as carboxylic acid and sulfonic acid, salts of acid dyes and nitrogen compounds, and sulfonamides of acid dyes.

[0119] Examples of such dyes include: Acid Alizarin Violet N; Acid Black 1, 2, 24, 48; Acid Blue 1, 7, 9, 25, 29, 40, 45, 62, 70, 74, 80, 83, 90, 92, 112, 113, 120, 129, 147; Acid Chrome Violet K; Acid Magenta; Acid Green 1, 3, 5, 25, 27, 50; Acid Orange 6, 7, 8, 10, 12, 50, 51, 52, 56, 63, 74, 95; Acid Red 1, 4, 8, 14, 17, 18, 26, 27, 29, 31, 34, 35, 37, 42, 44, 50, 51, 52, 57. 69, 73, 80, 87, 88, 91, 92, 94, 97, 103, 111, 114, 129, 133, 134, 138, 143, 145, 150, 151, 158, 176, 183, 198, 211, 215, 216, 217, 249, 252, 257, 260, 266, 274; Acid Violet 6B, 7, 9, 17, 19; Acid Yellow 1, 3, 9, 11, 17, 23, 25, 29, 34, 36, 42, 54, 72, 73, 76, 79, 98, 99, 111, 112, 114, 116; Food Yellow 3 and its derivatives, etc. Among these dyes, acidic dyes based on azo, dibenzopiperanone, anthraquinone, or phthalocyanine are preferred. These dyes can be used alone or in combination of two or more, depending on the color of the cured product of the target resin composition.

[0120] As examples of pigments, examples include CI pigments yellow 1, 3, 12, 13, 14, 15, 16, 17, 20, 24, 31, 53, 83, 86, 93, 94, 109, 110, 117, 125, 128, 137, 138, 139, 147, 148, 150, 153, 154, 166, 173, 194, 214, etc.; CI pigments orange 13, 31, 36, 38, 40, 42, 43, 51, 55, 59, 61, 64, 65, 71, 73, etc.; CI pigments red 9, 97, 105, etc. The product range includes red pigments such as CI pigments 122, 123, 144, 149, 166, 168, 176, 177, 180, 192, 209, 215, 216, 224, 242, 254, 255, 264, and 265; blue pigments such as CI pigments Blue 15, 15:3, 15:4, 15:6, and 60; purple pigments such as CI pigments Violet 1, 19, 23, 29, 32, 36, and 38; green pigments such as CI pigments Green 7, 36, 58, and 59; brown pigments such as CI pigments Brown 23 and 25; and black pigments such as CI pigments Black 1 and 7, carbon black, titanium black, and iron oxide. These pigments, depending on the color of the cured product of the target resin composition, can be used alone or in combination of two or more.

[0121] When using pigments as colorants (E), from the viewpoint of improving the dispersibility of the pigments, the resin composition may contain known dispersants. As a dispersant, it is preferable to use a polymeric dispersant with excellent dispersion stability over time. Examples of polymeric dispersants include carbamate-based dispersants, polyethyleneimine-based dispersants, polyoxyethylene alkyl ether-based dispersants, polyoxyethylene glycol diester-based dispersants, sorbitan aliphatic ester-based dispersants, and aliphatic modified ester-based dispersants.

[0122] As a polymeric dispersant, commercially available products under trade names such as EFKA (manufactured by EFKA Chemicals BV (EFKA) Co., Ltd.), Disperbyk-161 (manufactured by BYK Co., Ltd.), DISPARLON (manufactured by Kusumoto Chemical Co., Ltd.), and SOLSPERSE (manufactured by Zeneca Co., Ltd.) can also be used. The type and amount of dispersant can be appropriately set according to the type of pigment used.

[0123] When the resin composition contains a colorant (E), its content is preferably 3 to 80 parts by mass, more preferably 5 to 70 parts by mass, and even more preferably 10 to 60 parts by mass, relative to 100 parts by mass of the total mass of the copolymer (A) and the reactive diluent (C). The resin composition containing the copolymer (A) in this embodiment exhibits excellent storage stability, and a cured product with excellent solvent resistance can be obtained even when cured at low temperatures. Therefore, for example, the content of the colorant (E) can be set to 20 parts by mass or more relative to 100 parts by mass of the total mass of the copolymer (A) and the reactive diluent (C). A resin composition containing 20 parts by mass or more of the colorant (E), when used as a material for a color filter, can improve the color reproduction in an image display element equipped with a color filter.

[0124] In addition to the above-mentioned components, the resin composition of this embodiment may also incorporate known additives such as coupling agents, leveling agents, and thermal polymerization inhibitors to impart specific properties. The amount of these additives incorporated is not particularly limited, provided it does not impair the effects of the present invention.

[0125] Since the resin composition of this embodiment contains the copolymer (A) of this embodiment, the crosslinking reaction can proceed sufficiently even at low temperatures. Therefore, the resin composition of this embodiment can be cured at low temperatures. Specifically, it is preferable to cure the resin composition of this embodiment at a temperature of 150°C or below, more preferably 100°C or below, and most preferably 80°C or below. If the temperature for curing the resin composition is 150°C or below, the amount of energy required to cure the resin composition is small. Furthermore, when the resin composition contains a colorant (E) with poor heat resistance, the deterioration of the colorant (E) accompanying heat curing can be suppressed, and a cured product that exhibits the original properties of the colorant (E) can be easily obtained. Therefore, various materials can be used as the colorant (E). Furthermore, when a cured product is formed by coating the resin composition onto a substrate and then heat curing it, a cured product can be formed even if the substrate is made of a material with poor heat resistance. Therefore, various materials, such as resins used for flexible displays, can be used as substrates.

[0126] The resin composition of this embodiment is preferably cured at a temperature of 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher. If the curing temperature of the resin composition is 50°C or higher, the cross-linked structure caused by transesterification can be fully generated in a short time, and a cured product with good solvent resistance can be formed efficiently. The heating time (curing time) used to cure the resin composition in this embodiment can be appropriately determined according to the size and thickness of the cured product, the curing temperature, etc., for example, it can be set to 10 minutes to 4 hours, and 20 minutes to 2 hours is preferred.

[0127] The resin composition of this embodiment can be manufactured using a known mixing apparatus by mixing the above-mentioned components. The solvent contained in each component used as a raw material when manufacturing the resin composition of this embodiment can be used as solvent (B). When the resin composition of this embodiment contains components other than copolymer (A) and solvent (B), it can be manufactured, for example, by adding a mixed reactive diluent (C), a photopolymerization initiator (D), and a colorant (E) to a resin composition containing a pre-manufactured copolymer (A) and solvent (B).

[0128] The resin composition of this embodiment, since it contains the copolymer (A) of this embodiment, exhibits excellent storage stability, and a cured product with excellent solvent resistance can be obtained even when it is cured at low temperature. Therefore, the resin composition of this embodiment can be preferably used as a material for, for example, color filters, black matrices, color filter protective films, optical spacers, protrusions for liquid crystal alignment, microlenses, insulating films for touch panels, adhesives for electronic materials around flexible printed circuit boards, and adhesive sheets.

[0129] When the resin composition of this embodiment contains the copolymer (A), solvent (B), reactive diluent (C), and photopolymerization initiator (D) of this embodiment, it can be preferably used as a photosensitive material with good alkaline developability. In particular, it is suitable as a resist for use in color filters incorporated into organic electroluminescent (EL) displays (for black pixel definition layer (PDL)), liquid crystal display devices, and solid-state imaging devices using charge-coupled device (CCD) / complementary metal-oxide-semiconductor (CMOS) elements.

[0130] Furthermore, when the resin composition of this embodiment contains the copolymer (A), solvent (B), reactive diluent (C), photopolymerization initiator (D), and colorant (E) of this embodiment, a colored pattern formed from a curing material with excellent solvent resistance at low temperatures can be formed. Therefore, the deterioration of the colorant (E) accompanying heat curing can be suppressed, and a colored pattern that exhibits the inherent properties of the colorant (E) can be formed. Therefore, the above-mentioned resin composition can be preferably used as a photosensitive material for color filters.

[0131] <Color Filter> Next, the color filter of this embodiment will be described. The color filter of this embodiment has a substrate, a plurality of pixels formed by three color patterns: red (R) pattern, green (G) pattern and blue (B) pattern formed on the substrate, a black matrix formed at the boundaries of each color pattern, and a protective film formed on the pixels and the black matrix.

[0132] As the substrate, known materials can be used, such as glass substrates, silicon substrates, polycarbonate substrates, polyester substrates, polyamide substrates, polyamide-imide substrates, polyimide substrates, aluminum substrates, printed wiring substrates, array substrates, etc. In the color filter of this embodiment, organic substrates with relatively low heat resistance temperatures, such as polycarbonate substrates, polyester substrates, polyamide substrates, polyamide-imide substrates, and polyimide substrates, can be used as substrates suitable for flexible substrates.

[0133] In the color filter of this embodiment, the three color patterns forming the black matrix and each pixel are formed by a cured material of the resin composition of this embodiment containing the copolymer (A), solvent (B), reactive diluent (C), photopolymerization initiator (D), and colorant (E). There are no particular limitations on the protective film, and known materials can be used.

[0134] Next, an example of a method for manufacturing a color filter according to this embodiment will be described. In manufacturing the color filter of this embodiment, firstly, a black matrix color pattern and three color patterns forming each pixel are formed on a substrate. First, a black matrix color pattern is formed on the substrate. Then, within the area divided by the black matrix, a red pattern, a green pattern, and a blue pattern forming each pixel are formed. The order in which the red pattern, the green pattern, and the blue pattern are formed is not particularly limited.

[0135] Each colored pattern can be formed using the resin composition of this embodiment by photolithography. Specifically, the resin composition of this embodiment is coated onto a substrate to form a coating film. Next, the coating film is exposed to light through a photomask with a specified pattern shape, causing the exposed portion to photocur. Then, the unexposed portion of the coating film is developed and removed using an alkaline aqueous solution. Afterward, the exposed portion of the coating film is heated and hardened by baking. Through the above steps, a colored pattern with a specified shape formed from the hardened resin composition of this embodiment can be obtained.

[0136] There are no particular limitations on the method for coating the resin composition to form a colored pattern, and methods such as screen printing, roller coating, curtain coating, spray coating, and spin coating can be used. After coating the resin composition, the coated film can be heated as needed using heating means such as a circulating oven, infrared heater, or heating plate to evaporate and remove the solvent (B) contained in the coated film. The heating to remove the solvent (B) from the coated film can be performed, for example, at a temperature of 50°C to 120°C. The heating to remove the solvent (B) from the coated film can be performed, for example, for 30 seconds to 30 minutes. The heating temperature and heating time for removing the solvent (B) from the coated film can be appropriately set according to the composition of the resin composition and the thickness of the coated film.

[0137] When exposing the coated film, a known negative mask can be used as the photomask. It is preferable to use an active energy line such as ultraviolet light or excimer laser light when exposing the coated film. There are no particular limitations on the light source used for exposure; for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, or a metal halide lamp can be used. The energy line intensity for irradiating the coated film can be appropriately selected based on the thickness of the coated film and the composition of the resin components; for example, it can be set to 30~2000 mJ / cm².

[0138] For use in alkaline developing solutions, without particular limitation, aqueous solutions of, for example, sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, etc.; aqueous solutions of amine compounds such as ethylamine, diethylamine, dimethylethanolamine, etc.; aqueous solutions of p-phenylenediamine compounds such as tetramethylammonium, 3-methyl-4-amino-N,N-diethylaniline, 3-methyl-4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfonyl ethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methoxyethylaniline, and their sulfates, hydrochlorides, or p-toluenesulfonates, etc., can be appropriately selected depending on the composition of the resin components. Defoamers and surfactants may also be added to these alkaline aqueous solutions as needed. Furthermore, in this embodiment, after alkaline development caused by the alkaline solution and before baking, it is preferable to wash the substrate with water to remove the alkaline solution and allow it to dry.

[0139] In this embodiment, the temperature at which the exposed portion of the coating film is heated and hardened by baking can be appropriately selected depending on the thickness of the coating film and the composition of the resin composition. In this embodiment, since the coating film is formed using the resin composition containing copolymer (A) of this embodiment, the exposed portion of the coating film can be hardened even at low temperatures.

[0140] The temperature of the exposed portion of the heated coating film can be set to, for example, 210°C or below, or, depending on the need, 150°C or below, 100°C or below, or even 80°C or below. If the temperature of the exposed portion of the heated coating film is 210°C or below, materials with low heat resistance, such as substrates with low heat resistance, can be used as materials for color filters. When the temperature of the exposed portion of the heated coating film is set to 150°C or below, the amount of energy required to harden the coating film is less, which is preferable. Furthermore, if the temperature of the exposed portion of the heated coating film is 150°C or below, a color pattern containing a heat-resistant colorant (E) that is difficult to use as a material for conventional color patterns can be formed while suppressing the degradation of the colorant (E). Furthermore, when the temperature of the exposed portion of the heated coating film is set to 150°C or below, a color pattern can be formed on a substrate with poor heat resistance that is difficult to use as a substrate for color filters in the past.

[0141] The temperature of the exposed portion of the heated coating film is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher. If the temperature of the exposed portion of the heated coating film is 50°C or higher, the copolymer (A) and reactive diluent (C) are fully cross-linked, resulting in good solvent resistance of the colored pattern and the acquisition of a good pattern shape. Furthermore, if the temperature of the exposed portion of the heated coating film is 50°C or higher, the exposed portion of the coating film can be heated for a short time, efficiently producing the colored pattern. The heating time of the exposed portion of the heated coating film can be appropriately selected based on the temperature of the exposed portion of the heated coating film, the thickness of the coating film, and the composition of the resin components, for example, it can be set to 10 minutes to 4 hours, preferably 20 minutes to 2 hours.

[0142] Next, a protective film is formed on the color pattern that becomes a black matrix and the three color patterns that form each pixel by a known method. Through the above steps, the color filter of this embodiment can be obtained.

[0143] The color filter of this embodiment forms three color patterns for each pixel and a black matrix by forming a cured product of a resin composition of this embodiment containing a copolymer (A), a solvent (B), a reactive diluent (C), a photopolymerization initiator (D), and a colorant (E). The resin composition of this embodiment has good alkaline developability, and even when cured at low temperatures, a cured product with excellent solvent resistance can be obtained. Therefore, in the color filter of this embodiment, pixels and a black matrix can be formed by using a method of curing the resin composition at low temperatures, and there are many options for materials that can be used in the color filter.

[0144] Therefore, in the color filter of this embodiment, for example, it can be made to contain a colorant (E) with poor heat resistance and have pixels and / or a black matrix with good graphic shape. Furthermore, by using a method of curing the resin composition at low temperature to form pixels and a black matrix, a color filter having a substrate made of a material with poor heat resistance can be made.

[0145] In contrast, when using a conventional resin composition to form a colored pattern instead of the resin composition of this embodiment, if the temperature at which the exposed portion of the heated coating film is heated to harden does not reach 210°C, the solvent resistance of the hardened colored pattern is insufficient. Therefore, when using a conventional resin composition to form a colored pattern, the temperature of the exposed portion of the heated coating film cannot be set below 210°C. Therefore, in the conventional art, it is difficult to use a colorant (E) with poor heat resistance as the material for the colored pattern. Furthermore, it is also difficult to use a substrate with poor heat resistance as the substrate for the color filter.

[0146] In the color filter of this embodiment, for example, a pixel and a black matrix are formed by a cured resin composition containing a copolymer (A), solvent (B), reactive diluent (C), photopolymerization initiator (D), and colorant (E) of this embodiment. However, instead of the photopolymerization initiator (D), a resin composition incorporating a curing accelerator and a known epoxy resin may also be used.

[0147] In this case, for example, a colored pattern can be formed by the method shown below. First, a resin composition is coated onto a substrate by inkjet printing to form a coating film with a specified pattern shape. Next, the coating film is heated to harden it. By the above method, a colored pattern with a desired shape can be formed from the hardened resin composition. Instead of the photopolymerization initiator (D), a resin composition incorporating a curing accelerator and a known epoxy resin can also produce a hardened product with excellent solvent resistance even when cured at low temperatures. Therefore, in this case, a method of curing the resin composition at low temperatures can also be used to form pixels and black matrices, and there are many options for materials that can be used in color filters.

[0148] <Image Display Element> Next, the image display element of this embodiment will be described. Regarding the liquid crystal display element of this embodiment, for example, a first substrate with a color filter and a first electrode formed on its surface and a second substrate with a second electrode formed on its surface are arranged with the first electrode and the second electrode facing each other via a separator, and a liquid crystal composition is sandwiched between the first substrate and the second substrate. In the liquid crystal display element of this embodiment, the color filter of this embodiment is provided. For components other than the color filter in the liquid crystal display element of this embodiment, known components can be used.

[0149] The liquid crystal display element of this embodiment can be manufactured, for example, using the manufacturing method described below. First, a color filter and a first electrode are sequentially formed on a first substrate. The color filter can be formed using the manufacturing method described above. The first electrode can be formed using a known method. Next, a second electrode and a separator are formed on a second substrate using a known method. Then, the first and second substrates are disposed and bonded with the first and second electrodes facing each other, and liquid crystal composition is injected between the first and second substrates for encapsulation. By the above steps, the liquid crystal display element of this embodiment can be obtained.

[0150] Since the liquid crystal display element of this embodiment has the color filter of this embodiment, the pixels and black matrix of the color filter can be formed by curing the resin composition at low temperature. Therefore, as a material that can be used in the liquid crystal display element, materials with poor heat resistance can be used, and there are many options for materials that can be used.

[0151] In the above embodiment, although a liquid crystal display element is used as an example of the image display element of this embodiment, the image display element of this embodiment is not limited to a liquid crystal display element as long as it has the color filter of this embodiment. The image display element of this embodiment can also be, for example, an organic EL display element or a solid-state imaging device using a CCD element / CMOS element. [Example]

[0152] Hereinafter, the present invention will be further described in detail by way of examples and comparative examples. In addition, the present invention is not limited to the following examples only.

[0153] [Synthesis Example 1] In a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 212.5 g of propylene glycol monomethyl ether (manufactured by Sankyo Chemical Co., Ltd.) as solvent (B-1) was added, and nitrogen substitution was carried out while stirring, and the temperature was raised to 78°C (solvent heating step (I)).

[0154] Next, 26.9 g of 2,2'-azobis(2,4-dimethylvaleronitrile) (polymerization initiator) was dissolved in 77.3 g of propylene glycol monomethyl ether as solvent (B-2) to prepare a polymerization initiator solution. Also, 41.0 g (13 mol%) of MOI-DEM, 37.4 g (26 mol%) of 4-hydroxybutyl acrylate, 19.8 g (23 mol%) of methacrylic acid, and 69.9 g (38 mol%) of 2-ethylhexyl acrylate (2EHA) were dissolved in 60.5 g of propylene glycol monomethyl ether as solvent (B-2) and mixed to prepare a monomer solution. Subsequently, in the aforementioned flask containing solvent (B-1h) heated to 78°C, drop polymerization was carried out simultaneously using a dropping funnel to prepare a mixed solution of polymerization initiator solution and monomer solution (drop polymerization step (II)). The dropping rate for both the polymerization initiator solution and monomer solution was set at 1.7 ml / min.

[0155] After the dripping was completed, the mixed solution was stirred and reacted at 78°C for 3 hours to generate copolymer (A) (post-polymerization step (III)). Propylene glycol monomethyl ether, as solvent (B), was added to the reaction solution containing copolymer (A) obtained in this way, with the component other than solvent being 35% by mass, to obtain the polymer composition of Synthesis Example 1.

[0156] [Synthesis Examples 2-11, Comparative Synthesis Examples 1-3] Except that the materials listed in Tables 1-3 were used in the proportions listed in Tables 1-3, the same procedure as in Synthesis Example 1 was followed to obtain the polymer compositions of Synthesis Examples 2-11 and Comparative Synthesis Examples 1-3.

[0157] [Synthesis Example 12] In a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 212.5 g of propylene glycol monomethyl ether (manufactured by Sankyo Chemical Co., Ltd.) as solvent (B-1) and 1.75 g of mercaptoacetic acid as chain transfer agent were added. Nitrogen substitution was carried out while stirring, and the temperature was raised to 78°C (solvent heating step (I)).

[0158] Next, 26.9 g of 2,2'-azobis(2,4-dimethylpentanonitrile) (polymerization initiator) was dissolved in 77.3 g of propylene glycol monomethyl ether as solvent (B-2) to prepare a polymerization initiator solution. Also, 63.0 g (20 mol%) of MOI-DEM, 57.6 g (40 mol%) of 4-hydroxybutyl acrylate, 17.2 g (20 mol%) of methacrylic acid, and 36.8 g (20 mol%) of 2-ethylhexyl acrylate (2EHA) were dissolved in 60.5 g of propylene glycol monomethyl ether as solvent (B-2) to prepare a monomer solution. Subsequently, in the aforementioned flask containing solvent (B-1h) heated to 78°C, drop polymerization was carried out simultaneously using a dropping funnel to prepare a mixed solution of polymerization initiator solution and monomer solution (drop polymerization step (II)). The dropping rate for both the polymerization initiator solution and monomer solution was set at 1.7 ml / min.

[0159] After the dripping was completed, the mixed solution was stirred and reacted at 78°C for 3 hours to generate copolymer (A) (post-polymerization step (III)). Propylene glycol monomethyl ether, as solvent (B), was added to the reaction solution containing copolymer (A) obtained in this way, with the component other than solvent being 35% by mass, to obtain the polymer composition of Synthesis Example 12.

[0160]

[0161]

[0162]

[0163] In Tables 1 to 3, (ma) represents monomers having the groups shown in formula (1) or formula (2) above. (mb) represents monomers containing hydroxyl groups. (mc) represents monomers containing acid groups. (d) represents other monomers that do not conform to (ma), (mb), or (mc). Also, in Tables 1 to 3, (equivalent number of formulas (1) and (2)) represents the equivalent number of the groups shown in formula (1) or formula (2) above contained in the molecule of copolymer (A).

[0164] The materials used in Tables 1 to 3 are as follows: ・MOI-DEM: Karenz (registered trademark) MOI-DEM (formed by the reaction of 2-isocyanoethyl methacrylate and diethyl malonate, manufactured by Showa Denko Co., Ltd.) ・AOI-DEM: Karenz (registered trademark) AOI-DEM (formed by the reaction of 2-isocyanoethyl methacrylate and diethyl malonate, manufactured by Showa Denko Co., Ltd.) ・4-Hydroxybutyl acrylate (manufactured by Mitsubishi Chemical Co., Ltd.) ・2-Hydroxyethyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) ・2-Hydroxyethyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd.) ・2-Hydroxypropyl acrylate (HOP-A(N)) (manufactured by Kyoeisha Chemical Co., Ltd.) ・Methacrylic acid (manufactured by Kuraray Co., Ltd.) ・Acrylic acid (manufactured by Toa Synthetic Co., Ltd.)

[0165] ・2EHA: 2-Ethylhexyl acrylate (manufactured by Toa Synthetic Co., Ltd.)・TCDMA: Tricyclo[5.2.1.02,6]decyl-8-methacrylate (manufactured by Hitachi Chemical Co., Ltd.)・GMA: Glycidyl methacrylate (manufactured by Nippon Oil Co., Ltd.)・MOI-BP: Karenz (registered trademark) MOI-BP (2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, manufactured by Showa Denko Co., Ltd.)・MOI-BM: Karenz (registered trademark) MOI-BM (2-[O-(1'-methylpropylamino)carboxylamino]ethyl methacrylate, manufactured by Showa Denko Co., Ltd.)

[0166] Regarding the polymer compositions of Synthetic Examples 1 to 12 and Comparative Synthetic Examples 1 to 3 shown in Tables 1 to 3, the weight-average molecular weight (Mw), glass transition temperature (Tg), storage stability, and acid value were measured and evaluated using the methods shown below. The results are presented in Tables 1 to 3.

[0167] <Weight-Average Molecular Weight (Mw)> The weight-average molecular weight (Mw) of the copolymers (A) contained in the polymer compositions of Synthetic Examples 1-12 and Comparative Synthetic Examples 1-3 was determined. The weight-average molecular weight is the weight-average molecular weight converted from that of standard polystyrene determined using gel permeation chromatography (GPC) under the following conditions. Column: Shodex LF-804+LF-804 (manufactured by Showa Denko Co., Ltd.) Column temperature: 40℃ Sample: 0.2% by mass tetrahydrofuran solution of copolymer Developing solvent: Tetrahydrofuran Detector: Differential refractometer (Shodex RI-71S) (manufactured by Showa Denko Co., Ltd.) Flow rate: 1 mL / min

[0168] <Glass Transition Temperature (Tg)> The polymer compositions of Synthetic Examples 1-12 and Comparative Synthetic Examples 1-3 were coated onto a glass substrate and dried at 50°C under reduced pressure for 24 hours. Afterwards, they were dissolved in acetone and dried again at 50°C under reduced pressure for 24 hours. The solid content of the copolymer solution after removing volatile components was measured using DSC (differential scanning calorimeter, measuring instrument: SEIKO DSC6200) under a nitrogen flow at a heating rate of 10°C / min according to JIS-K7121 (midpoint glass transition point). The obtained result was defined as the glass transition temperature (Tg) of copolymer (A).

[0169] <Storage Stability> After adjustment, equal amounts of the polymer compositions of Synthetic Examples 1-12 and Comparative Synthetic Examples 1-3, excluding the solvent, at 35% by mass, were measured into glass containers and covered to prevent dust from entering, thus preparing samples. After measuring the viscosity of each sample, they were placed in a thermostat maintained at 12°C for 3 months. Then, the viscosity of each sample after 3 months of standing was measured. In addition, the viscosity was measured using an E-type viscometer (RE-80L, manufactured by Toki Sangyo, cone No. 3) at 25°C and 10 rpm.

[0170] For each sample, calculate the viscosity increase rate after 3 months of standing relative to the viscosity before standing in the thermostat {(1-(viscosity after 3 months of standing / viscosity before standing))×100(%)}, and evaluate it using the following criteria: ◎: Viscosity increase rate less than 10% ○: Viscosity increase rate 10.1%~20% △: Viscosity increase rate greater than 20.1%

[0171] As shown in Tables 1 to 3, it can be confirmed that the polymer compositions of Synthetic Examples 1 to 12 and Comparative Synthetic Examples 1 to 3 all have a storage stability rating of ◎ or ○, indicating excellent storage stability.

[0172] <Acid Value> The acid value of the polymer compositions of Synthetic Examples 1-12 and Comparative Synthetic Examples 1-3 was determined and defined as the acid value of copolymer (A). This is the acid value of the curing polymer determined according to JIS K6901 5.3. That is, the acid value refers to the number of mg of potassium hydroxide required to neutralize the acidic components contained in 1g of the copolymer.

[0173] [Examples 1-12, Comparative Examples 1-3] The polymer compositions of Synthetic Examples 1-12 and Comparative Examples 1-3 shown in Tables 1-3 were mixed in the proportions shown in Table 4, propylene glycol monomethyl ether acetate as (B) solvent, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.) as (C) reactive diluent, acetone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, 1-(o-acetyloxime) (manufactured by BASF Japan Co., Ltd.) as (D) photopolymerization initiator, and dye (VALIFAST Blue 2620) as (E) colorant to prepare the resin compositions of Examples 1-12 and Comparative Examples 1-3.

[0174]

[0175] The copolymer (A) shown in Table 4 does not include the amount of solvent contained in the reaction solution used in the manufacture of copolymer (A). The amount of solvent (B) shown in Table 4 is the total amount calculated by combining the solvent (propylene glycol monomethyl ether) contained in the polymer composition and the solvent (propylene glycol monomethyl ether acetate) added during the manufacture of the resin composition. The proportion of hydroxyl-containing solvents in solvent (B) shown in Table 4 is 79.1% by mass.

[0176] Regarding the resin compositions of Examples 1-12 and Comparative Examples 1-3, their alkali developability and solvent resistance were evaluated using the method shown below. (1) Alkali developability: The resin compositions of the Examples and Comparative Examples were spin-coated onto a planar square glass substrate (alkali-free glass substrate) with a thickness of 5 cm in length and 5 cm in width to form a coating film, with the thickness after exposure being 2.5 μm. Then, the solvent in the coating film was evaporated and removed by heating at 100°C for 3 minutes.

[0177] Next, a photomask with a specified pattern is placed at a distance of 100 μm from the coated film. The coated film is then exposed to ultraviolet light with an energy linearity of 40 mJ / cm² and a wavelength of 365 nm through this photomask to photocur the exposed areas. Next, an aqueous solution containing 0.1% by mass of sodium carbonate is sprayed at a temperature of 23°C and a pressure of 0.3 MPa to dissolve the unexposed areas and develop the film. Afterward, the specified pattern is formed by baking at 100°C for 20 minutes.

[0178] Then, by observing the pattern after alkaline development using an electron microscope S-3400 manufactured by Hitachi Advanced Technology Co., Ltd., the residue after alkaline development was confirmed and evaluated according to the criteria shown below. The results are shown in Table 5. ○: No residue in unexposed areas ×: Residue in unexposed areas

[0179] (2) Solvent resistance: The resin compositions of the examples and comparative examples were spin-coated onto a square glass substrate (alkali-free glass substrate) with a length of 5 cm and a width of 5 cm to form a coating film, with the thickness after exposure being 2.5 μm. Then, the solvent in the coating film was evaporated and removed by heating at 100°C for 3 minutes.

[0180] Next, the coating was exposed to ultraviolet light at a wavelength of 365 nm with an energy linearity of 40 mJ / cm² to photocur the exposed portion. Afterward, the coating was baked at 80°C for 30 minutes or at 100°C for 20 minutes to harden it into a cured film. The cured film was then immersed in 20 g of propylene glycol monomethyl ether at 23°C for 15 minutes. The color change (ΔEab) before and after immersion was measured using a UV-1650PC spectrophotometer (manufactured by Shimadzu Corporation). Based on the results, the solvent resistance was evaluated. The results are shown in Table 5.

[0181]

[0182] As shown in Table 5, the hardened films obtained by curing the resin compositions of Examples 1-12 showed good alkali developability. Furthermore, the hardened films obtained by curing the resin compositions of Examples 1-12 showed good solvent resistance in either the case where the curing temperature was set to 80°C and the time to be 30 minutes, or the case where the temperature was set to 100°C and the time to be 20 minutes.

[0183] On the other hand, although the cured films obtained by curing the resin compositions of Comparative Examples 1-3 showed good alkali developability, the ΔEab value was 3 or higher when the curing temperature was set to 80°C and the time to be set to 30 minutes, indicating insufficient solvent resistance. [Industrial Applicability]

[0184] According to the present invention, a resin composition exhibiting good alkaline developability and excellent storage stability when used as a photosensitive material, and a cured product with excellent solvent resistance even when cured at low temperatures, a copolymer useful for preparing this resin composition, and a method for manufacturing the copolymer are provided. Furthermore, according to the present invention, a colored pattern formed from a cured product of a resin composition exhibiting good developability and excellent solvent resistance even when cured at low temperatures, a color filter having the same, and an image display element having the color filter are provided. The resin composition of the present invention is preferably used in a wide range of applications as a material for transparent films, protective films, insulating films, outer coatings, light spacers, black matrices, black tube column separators, resists for color filters, etc.

Claims

1. A copolymer characterized by comprising structural units (a) 1-40 mol% having a group as shown in formula (1) or formula (2) below, structural units (b) 1-60 mol% having a hydroxyl group, and structural units (c) 1-60 mol% having an acid group, wherein the acid value is 20-300 mg / g of KOH, and the glass transition temperature is below 30°C.

1. (In formula (1), R1 and R2 are independent and represent alkyl groups with 1 to 10 carbon atoms; * indicates the linking site), 1. (In formula (2), R3 represents an alkyl group with 1 to 10 carbon atoms; * indicates a linking site).

2. The copolymer of claim 1, wherein the aforementioned structural unit (b) is a structural unit derived from hydroxyalkyl (meth)acrylate.

3. The copolymer of claim 1 or claim 2, wherein the aforementioned structural unit (c) is a structural unit derived from an unsaturated carboxylic acid.

4. The copolymer of claim 1 or claim 2, wherein the aforementioned structural unit (a) is a structural unit derived from a compound having a radical and (meth)acryloxy group as shown in the aforementioned formula (1) or the aforementioned formula (2).

5. The copolymer of claim 1 or claim 2, wherein the molar ratio of the total amount of ester groups contained in the base of the aforementioned formula (1) or formula (2) to the total amount of hydroxyl groups contained in the aforementioned structural unit (b) is 10:90 to 90:

10.

6. The copolymer of claim 1 or claim 2, wherein the weight average molecular weight is 1,000 to 50,000.

7. A resin composition characterized by comprising a copolymer (A) of any one of claims 1 to 6 and a solvent (B), wherein the solvent (B) comprises a hydroxyl-containing solvent.

8. The resin composition of claim 7 further contains a reactive diluent (C) and a photopolymerization initiator (D).

9. The resin composition of claim 8 further contains a colorant (E).

10. The resin composition of claim 9, wherein, relative to 100 parts by mass of the copolymer (A) and the reactive diluent (C), it comprises: 10 to 90 parts by mass of the copolymer (A), 30 to 1000 parts by mass of the solvent (B), 10 to 90 parts by mass of the reactive diluent (C), 0.1 to 30 parts by mass of the photopolymerization initiator (D), and 3 to 80 parts by mass of the colorant (E).

11. A color filter, characterized in that it has a colored pattern formed from a hardened material of a resin composition as described in claim 9 or claim 10.

12. An image display element, characterized in that it has a color filter as claimed in claim 11.

13. A method for manufacturing a copolymer as claimed in any one of claims 1 to 6, characterized by comprising the following steps (I) to (III): a solvent heating step (I) of heating solvent (B-1) to 60-90°C to prepare a heated solvent (B-1h); a dropwise polymerization step (II) of dissolving a monomer (ma) having a group shown in formula (1) or formula (2), a hydroxyl-containing monomer (mb), and an acid-containing monomer (mc) in solvent (B-2) to form a monomer solution, and simultaneously dropping a polymerization initiator solution formed by dissolving a polymerization initiator in the aforementioned solvent (B-2) to form a mixed solution; and a post-polymerization step (III) of stirring the aforementioned mixed solution while reacting it at 60-90°C for 1-5 hours; wherein either or both of the aforementioned solvent (B-1) and the aforementioned solvent (B-2) contain a hydroxyl-containing solvent.

13. (In formula (1), R1 and R2 are independent and represent alkyl groups with 1 to 10 carbon atoms; * indicates the linking site), 13. (In formula (2), R3 represents an alkyl group with 1 to 10 carbon atoms; * indicates a linking site).

14. The method for manufacturing the copolymer of claim 13, wherein in the aforementioned solvent heating step (I), a chain transfer agent is added to the aforementioned solvent (B-1) and then the temperature is increased.