Alkali-soluble resin and photosensitive resin composition

Abstract

To provide an alkali-soluble resin constituting a photosensitive resin composition that enables formation of a cured resin film having a high refractive index and exhibits superior developability; to provide a photosensitive resin composition including the alkali-soluble resin, and a cured resin film having superior patternability and a high refractive index; and to provide an image display device including the cured resin film.SOLUTION: An alkali-soluble resin of the present invention has a group represented by the following formula (1). The acid value is 20 to 300 mgKOH / g. (R1 and R2 are independently -O-, -S-, or -N(R5); R4 is halogen, alkyl, alkoxy, or aromatic; R5 is H, alkyl, or alkoxy).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an alkali-soluble resin, a photosensitive resin composition, a resin cured film which is a cured product of the photosensitive resin composition, and an image display element including the resin cured film.

Background Art

[0002] In recent years, with the widespread use of liquid crystal displays, extensive research has been conducted on color filters used as components of liquid crystal displays, overcoat layers provided on these color filters, interlayer insulating films, and the like (for example, Patent Document 1, Patent Document 2). These materials often require a high refractive index.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, further improvement has been demanded for a material that combines a high refractive index and good developability.

[0005] An object of the present invention is to provide an alkali-soluble resin that constitutes a photosensitive resin composition capable of obtaining a resin cured film having a high refractive index and good developability. Another object is to provide a photosensitive resin composition containing the alkali-soluble resin, which has good patterning properties and a resin cured film having a high refractive index. Furthermore, an object is to provide an image display element including the resin cured film.

Means for Solving the Problems

[0006] The present invention includes the following aspects. [1] An alkali-soluble resin having a group represented by the following formula (1), characterized in that the acid value is 20 to 300 mgKOH / g. [Chemical formula] (In the formula, R 1 and R 2 are each independently -O-, -S-, or -N(R 5 )-, R 4 is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R 5 is H, an alkyl group, or an alkoxy group, and p is an integer of 0 to 4.) [2] The alkali-soluble resin according to [1], wherein the equivalent number of the group represented by the above formula (1) is 200 to 1100 g / mol. [3] The alkali-soluble resin according to [1] or [2], wherein the refractive index is 1.40 or more. [4] The alkali-soluble resin according to any one of [1] to [3], wherein the weight average molecular weight is 1000 to 50000. [5] The alkali-soluble resin according to any one of [1] to [4], wherein the alkali-soluble resin is a copolymer containing a structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) and a structural unit (a-2) having an acid group derived from an ethylenically unsaturated compound (ma-2). [6] With respect to 100 mol% of all structural units, the structural unit (a-1) is 10 to 95 mol%, the structural unit (a-2) is 5 to 90 mol%, and the alkali-soluble resin according to [5]. [7] The alkali-soluble resin is a first modified copolymer in which a compound having a group reactive with an epoxy group and an ethylenically unsaturated group is further added to a part of the epoxy groups of a copolymer containing a structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) and a structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group, and a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by ring-opening of the epoxy groups. The alkali-soluble resin according to any one of [1] to [4]. [8] With respect to a total of 100 mol% of the structural units constituting the first modified copolymer, the structural unit (a-1) is 10 to 95 mol%, the structural unit (a-3) is 5 to 90 mol%, and the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group with respect to the number of moles of the epoxy groups derived from the structural unit (a-3) is 10 to 90 mol%. The alkali-soluble resin according to [7]. [9] The alkali-soluble resin is a second modified copolymer in which a compound represented by the following formula (2) is added to a part of the epoxy groups of a copolymer containing a structural unit (a-2) derived from an ethylenically unsaturated compound (ma-2) having an acid group and a structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group. The alkali-soluble resin according to any one of [1] to [4]. [Chemical formula] (In the formula, R 2 is -O-, -S-, or -N(R 5 )-, R 4 is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R 12 is -OH, -SH, or -NHR 5 (wherein R 5 is H, an alkyl group, or an alkoxy group, and p is an integer of 0 to 4).)

[10] With respect to a total of 100 mol% of the structural units constituting the second modified copolymer, the structural unit (a-2) is 5 to 90 mol%, The structural unit (a-3) is 10 to 95 mol%, The addition rate of the compound represented by the above formula (2) to the number of moles of epoxy groups derived from the structural unit (a-3) is 10 to 90 mol%, and the alkali-soluble resin according to [9].

[11] The alkali-soluble resin is a third-modified copolymer in which a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by ring-opening of the epoxy groups of the second-modified copolymer, and the alkali-soluble resin according to [9] or

[10] .

[12] The alkali-soluble resin is a modified epoxy resin in which a compound represented by the following formula (2) is added to a part of the epoxy groups of the epoxy resin, and a polybasic acid or its anhydride is added to a part of the hydroxy groups generated by ring-opening of the epoxy groups, and the alkali-soluble resin according to any one of [1] to [4].

Chemical formula

[13] The addition rate of the compound represented by the above formula (2) to the number of moles of epoxy groups of the epoxy resin is 10 to 90 mol%, and the alkali-soluble resin according to

[12] .

[14] An alkali-soluble resin (A), A reactive diluent (B), A photopolymerization initiator (C), A solvent (D), and a photosensitive resin composition containing The alkali-soluble resin (A) is the alkali-soluble resin according to any one of [1] to

[13] , and the photosensitive resin composition.

[15] Based on a total of 100% by mass of the alkali-soluble resin (A) and the reactive diluent (B), The alkali-soluble resin (A) is 10 to 99% by mass, the reactive diluent (B) is 1 to 90% by mass, based on 100 parts by mass in total of the alkali-soluble resin (A) and the reactive diluent (B), the photopolymerization initiator (C) is 0.1 to 30 parts by mass, based on 100 parts by mass in total of the components excluding the solvent (D), the solvent (D) is 30 to 1000 parts by mass, the photosensitive resin composition according to

[14] .

[16] A resin cured film comprising a cured product of the photosensitive resin composition according to

[14] .

[17] An image display device including the resin cured film according to

[16] . [Advantages of the Invention]

[0007] According to the present invention, a resin cured film having a high refractive index can be obtained, and an alkali-soluble resin constituting a photosensitive resin composition having good developability can be provided. Further, a photosensitive resin composition containing an alkali-soluble resin, a resin cured film having good patterning properties and a high refractive index can be provided. Furthermore, an image display element including the resin cured film can be provided. [Embodiments for Carrying Out the Invention]

[0008] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments shown below.

[0009] In this specification, when "~" is used for a numerical range, the numerical values at both ends are the upper limit value and the lower limit value, respectively, and are included in the numerical range.

[0010] In this specification, “(meth)acrylic acid” means methacrylic acid or acrylic acid, “(meth)acrylate” means acrylate or methacrylate, and “(meth)acryloyloxy” means acryloyloxy or methacryloyloxy. When multiple upper limit values or lower limit values are described, a numerical range can be formed from all combinations of the upper limit values and the lower limit values. Similarly, when multiple numerical ranges are described, separate numerical ranges can be formed by individually selecting and combining the upper limit values and the lower limit values from those numerical ranges.

[0011] In this specification, the “ethylenically unsaturated bond” means a double bond formed between carbon atoms excluding the carbon atoms forming an aromatic ring, and the “ethylenically unsaturated monomer” means a monomer having an ethylenically unsaturated bond.

[0012] In this specification, the “structural unit” means a unit derived from an ethylenically unsaturated compound used as a monomer or a unit obtained by further modifying a unit derived from an ethylenically unsaturated compound used as a monomer.

[0013] In this specification, the “weight average molecular weight” and the “number average molecular weight” are values measured at room temperature (23°C) under the following conditions using gel permeation chromatography (GPC), and determined using a standard polystyrene calibration curve. Apparatus: GPC Prominence501 (Shimadzu Corporation) Column: Shodex (trademark) LF-804 + LF-804 (Resonac Co., Ltd.) Column temperature: 40°C Sample: 0.2 mass% tetrahydrofuran solution of the sample Flow rate: 1 mL / min Eluent: Tetrahydrofuran Detector: Shodex (trademark) RI-71S (Resonac Co., Ltd.)

[0014] In this specification, the "acid value" is the acid value of the resin measured according to JIS K6901 5.3. That is, the acid value means the number of milligrams of potassium hydroxide required to neutralize the acidic components contained in 1 g of the resin.

[0015] In this specification, the "refractive index" is a value calculated by the following method. That is, the refractive index of a resin composition (sample) containing a resin and a solvent is measured under the following conditions, and then the refractive index of the solvent is measured under the following conditions. Next, the content (solid content) of the resin contained in the sample is measured according to JIS K6901 5.11, and the refractive index of the resin alone contained in the sample is calculated using the following formula. Measuring instrument: J-357 Automatic Refractometer (Rudolph Research Analytical) Measurement wavelength: 589 nm Measurement temperature: 25 °C Refractive index of resin alone = (refractive index of sample - refractive index of solvent) ÷ solid content × 100 + refractive index of solvent

[0016] (Alkali-soluble resin) The alkali-soluble resin of one embodiment of the present invention (sometimes referred to as the alkali-soluble resin (A) of this embodiment) has a group represented by the following formula (1).

[0017] [Chemical formula] (In the formula, R 1 and R 2 are each independently -O-, -S-, or -N(R 5 )-, R 4 is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R 5 is H, an alkyl group, or an alkoxy group, and p is an integer from 0 to 4.) Note that ~~ represents the connection site with the residue obtained by removing the group of formula (1) from the structural unit.

[0018] Since the alkali-soluble resin (A) of the present embodiment has a group represented by the above formula (1), it becomes a resin having a high refractive index, so that a resin cured film having a high refractive index can be obtained. Further, the alkali-soluble resin (A) has good stability, and good transparency and developability can be obtained when it is made into a photosensitive resin composition. Furthermore, a resin cured film having both a high refractive index and patterning properties can be obtained.

[0019] R 1 From the viewpoints of ease of synthesis and availability of raw materials of the alkali-soluble resin (A), -S- is preferable for R. 2 From the viewpoints of refractive index and transparency, -S- is more preferable for R. p is preferably 0 or 1, more preferably 0, from the viewpoint of developability when it is made into a photosensitive resin composition. 4 Examples of the halogen group of R include a group having fluorine and a group having chlorine. 4 The alkyl group and alkoxy group of R are preferably an alkyl group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms from the viewpoint of developability when it is made into a photosensitive resin composition. 4 Examples of the aromatic group of R include a phenyl group and a naphthyl group.

[0020] Specific examples of the group represented by the above formula (1) include substituents represented by the following formulas (11) to (19). These substituents may be contained singly or in combination of two or more in the alkali-soluble resin (A).

[0021]

Chemical formula

[0022] The equivalent number of the group represented by the above formula (1) in the alkali-soluble resin (A) is Preferably, it is 1100 g / mol or less, more preferably 1000 g / mol or less, still more preferably 900 g / mol or less, and even more preferably 800 g / mol or less. The equivalent number of the group represented by the above formula (1) of the alkali-soluble resin (A) is preferably 200 g / mol or more, more preferably 250 g / mol or more, still more preferably 300 g / mol or more, and even more preferably 350 g / mol or more. Any combination of these lower limit values and upper limit values may be used. When the equivalent number of the group represented by the above formula (1) of the alkali-soluble resin (A) is 1100 g / mol or less, an alkali-soluble resin (A) having a high refractive index can be obtained, and a resin cured film having a sufficiently high refractive index can also be obtained. When the equivalent number of the group represented by the above formula (1) of the alkali-soluble resin (A) is 200 g / mol or more, a resin cured film having a good pattern can be obtained without affecting the developability of the photosensitive resin composition.

[0023] The equivalent number of the group represented by the above formula (1) is the mass of the alkali-soluble resin (A) per mole of the group represented by the above formula (1) in the alkali-soluble resin (A). The equivalent number of the group represented by the above formula (1) can be obtained by dividing the mass of the alkali-soluble resin (A) by the number of the groups represented by the above formula (1) in the resin (g / mol). In this specification, the equivalent number of the group represented by the above formula (1) of the alkali-soluble resin (A) is a theoretical value calculated from the charged amount of the raw material used for introducing the group represented by the above formula (1) into the resin.

[0024] The acid value of the alkali-soluble resin (A) is preferably 20 KOHmg / g or more, more preferably 30 KOHmg / g or more, still more preferably 35 KOHmg / g or more. The acid value of the alkali-soluble resin (A) is preferably 300 KOHmg / g or less, more preferably 200 KOHmg / g or less, still more preferably 150 KOHmg / g or less, and even more preferably 100 KOHmg / g or less. Any combination of these lower and upper limits may be used. When the acid value of the alkali-soluble resin (A) is 20 KOH mg / g or more, the developability of the photosensitive resin composition is good. When the acid value of the alkali-soluble resin (A) is 300 KOH mg / g or less, the storage stability of the photosensitive resin composition is good.

[0025] The refractive index of the alkali-soluble resin (A) is preferably 1.40 or more, more preferably 1.50 or more, and still more preferably 1.55 or more. The refractive index of the alkali-soluble resin (A) may be 1.85 or less, may be 1.80 or less, or may be 1.70 or less. Any combination of these lower and upper limits may be used. When the refractive index of the alkali-soluble resin (A) is 1.40 or more, the refractive index of the resin cured film becomes sufficiently high. Therefore, for example, when this is used for the insulating layer of a display material, it reduces the refraction at the interface between ITO or SiN x and the insulating layer, and has the effect of increasing the luminance from the backlight of the liquid crystal display.

[0026] The weight average molecular weight of the alkali-soluble resin (A) is preferably 1000 or more, more preferably 2000 or more, and still more preferably 3000 or more. The weight average molecular weight of the alkali-soluble resin (A) is preferably 50000 or less, more preferably 30000 or less, and still more preferably 20000 or less. Any combination of these lower and upper limits may be used. When the weight average molecular weight of the alkali-soluble resin (A) is within the above range, the patterning property is good. When the resin skeleton of the alkali-soluble resin (A) is a (meth)acrylic resin described later, from the viewpoint of radical polymerizability, it may be 4000 or more, may be 5000 or more, or may be 6000 or more. When the resin skeleton of the alkali-soluble resin (A) is an epoxy resin described later, from the viewpoint of developability, it may be 10000 or less, may be 7000 or less, or may be 5000 or less.

[0027] The molecular weight distribution (Mw / Mn) of the alkali-soluble resin (A) is preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more. The molecular weight distribution (Mw / Mn) of the alkali-soluble resin (A) is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. Any combination of these lower and upper limits may be used. When the molecular weight distribution (Mw / Mn) of the alkali-soluble resin (A) is 1.1 or more, it is easy to control the production conditions when synthesizing the alkali-soluble resin (A). When the weight average molecular weight of the alkali-soluble resin (A) is 5.0 or less, developability and storage stability can be ensured without variation as a photosensitive resin composition.

[0028] The alkali-soluble resin (A) is not particularly limited as long as it has an acid value within a specific range and has the group represented by the above formula (1), and various polymers conventionally used in photosensitive resin compositions can be used. Examples of such polymers include (meth)acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, phenol novolak resins, cresol novolak resins, polyimide precursors containing polyamic acid, epoxy resins, and organic polymer polymers soluble in an alkali developer such as polyimide resins having a carboxyl group or a hydroxyl group in the side chain. Note that the (meth)acrylic acid copolymer means both an acrylic acid copolymer and a methacrylic acid copolymer. Furthermore, the alkali-soluble resin also includes a resin that is regenerated by exposure to light and becomes alkali-soluble. Among these, from the viewpoint of achieving both high refractive index and developability, (meth)acrylic resins and epoxy resins are preferred, and the alkali-soluble resin (A-1), alkali-soluble resin (A-2), alkali-soluble resin (A-3), and alkali-soluble resin (A-4) described later are more preferred.

[0029] 〔Alkali-soluble resin (A-1)〕 The alkali-soluble resin (A-1) is a copolymer containing a structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) (hereinafter also simply referred to as "structural unit (a-1)") and a structural unit (a-2) having an acid group derived from an ethylenically unsaturated compound (ma-2) having an acid group (hereinafter also simply referred to as "monomer (ma-2)"). The alkali-soluble resin (A-1) is a copolymer of an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) and an ethylenically unsaturated compound (ma-2) having an acid group. The alkali-soluble resin (A-1) may contain, if necessary, a structural unit (a-4) derived from another ethylenically unsaturated compound (ma-4) (hereinafter also simply referred to as "structural unit (a-4)"). That is, the alkali-soluble resin (A-1) may be a copolymer of an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1), an ethylenically unsaturated compound (ma-2) having an acid group, and, if necessary, another ethylenically unsaturated compound (ma-4). By using the alkali-soluble resin (A-1), a photosensitive resin composition excellent in developability and storage stability can be obtained, and a resin cured film having a higher refractive index can be obtained. Since the alkali-soluble resin (A-1) is obtained only by a copolymerization reaction (only the first-stage synthesis), it is advantageous in that it is easy to manufacture. Further, since a modification reaction such as an addition reaction (second-stage synthesis) is not used, low-molecular-weight components derived from unreacted raw materials in the resin can be reduced, and the development residue when made into a photosensitive resin composition can be reduced. Furthermore, since unintended cross-linking between functional groups and generation of by-products can be suppressed, the molecular weight distribution can be controlled within a narrow range, and a photosensitive resin composition having good developability can be obtained even when the pattern of the resin cured film is thinned and the pitch is narrowed.

[0030] "structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1)" The structural unit (a-1) is a structural unit derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) (hereinafter, also simply referred to as "monomer (ma-1)"). Since the alkali-soluble resin (A-1) has the structural unit (a-1), an alkali-soluble resin (A-1) with a high refractive index can be obtained, and a resin cured film using the same also has a high refractive index.

[0031] The monomer (ma-1) that provides the structural unit (a-1) may be any compound that is copolymerizable with the monomer (ma-2) and other monomers (ma-4) described below, and is not particularly limited. As the monomer (ma-1), for example, from the viewpoint of reactivity when synthesizing the alkali-soluble resin (A-1), a monomer having a group represented by the above formula (1) and an ethylenically unsaturated bond can be used. Specific examples of the group having an ethylenically unsaturated bond include a vinyl group and a (meth)acryloyloxy group. From the viewpoint of the degree of freedom of the monomer blending ratio, the (meth)acryloyloxy group is preferred.

[0032] Examples of the monomer (ma-1) include a reaction product of an ethylenically unsaturated compound having an epoxy group and a compound represented by the following formula (2).

[0033] [Chemical formula] (In the formula, R 2 is -O-, -S-, or -N(R 5 )-, R 4 is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R 12 is -OH, -SH, or -NHR 5 , R 5 is H, an alkyl group, or an alkoxy group, and p is an integer from 0 to 4.)

[0034] The ethylenically unsaturated compound having an epoxy group for generating monomer (ma-1) is not particularly limited as long as it is a compound having an epoxy group and an ethylenically unsaturated group. For example, oxiranyl (meth)acrylate, glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 2-ethylglycidyl (meth)acrylate, 2-oxiranylethyl (meth)acrylate, 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxypropyl (meth)acrylate, glycidyloxyphenyl (meth)acrylate and other (meth)acrylate ester derivatives containing an epoxy group; 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 2-(3,4-epoxycyclohexyl)ethyl (meth)acrylate, 2-(3,4-epoxycyclohexylmethyloxy)ethyl (meth)acrylate, 3-(3,4-epoxycyclohexylmethyloxy)propyl (meth)acrylate and other (meth)acrylate ester derivatives containing an epoxy group-containing alicyclic carbocyclic ring such as a 3,4-epoxycyclohexane ring; vinyl ether compounds containing an epoxy group; allyl ether compounds containing an epoxy group and the like. These monomers may be used alone or in combination of two or more. Among these, from the viewpoints of polymerizability and ease of availability, (meth)acrylate ester derivatives containing an epoxy group and (meth)acrylate ester derivatives containing an epoxy group-containing alicyclic carbocyclic ring are preferred, and epoxy group-containing (meth)acrylates such as oxiranyl (meth)acrylate, glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 2-ethylglycidyl (meth)acrylate, 2-oxiranylethyl (meth)acrylate, 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxypropyl (meth)acrylate, glycidyloxyphenyl (meth)acrylate are preferred, and glycidyl (meth)acrylate is more preferred.

[0035] Regarding the compound represented by the above formula (2) for generating monomer (ma-1), R 12From the perspective of ease of reaction with ethylenically unsaturated compounds having an epoxy group, SH is preferred. R 2 Regarding the preferred ranges of R and p, they are the same as in the above formula (1). Specific examples of the compound represented by the above formula (2) include compounds represented by the following formulas (21) to (29). Among them, from the viewpoints of reactivity and ease of availability, 2-mercaptobenzothiazole and 2-mercaptobenzimidazole are preferred.

[0036] [Chemical formula] (In the formula, R 4 , R 5 and p are the same as above.)

[0037] "Structural unit (a-2) having an acid group" The structural unit (a-2) is a structural unit derived from an ethylenically unsaturated compound (ma-2) having an acid group (hereinafter also simply referred to as "monomer (ma-2)"). The structural unit (a-2) does not have the group represented by the above formula (1) and is not particularly limited as long as it has an acid group. Examples of the acid group include a carboxy group, a sulfo group, a phospho group, etc. Among these acid groups, from the viewpoint of developability as a photosensitive resin composition, a carboxy group is preferred. When the alkali-soluble resin (A-1) has the structural unit (a-2), good developability can be obtained as a photosensitive resin composition.

[0038] The monomer (ma-2) that provides the structural unit (a-2) does not have the group represented by the above formula (1), has an acid group, and is not particularly limited as long as it is a compound copolymerizable with the monomer (ma-1) and other monomers (ma-4) described later. As the monomer (a-2), for example, from the viewpoint of reactivity when synthesizing the alkali-soluble resin (A-1), a monomer having an acid group and an ethylenically unsaturated bond can be used. For example, unsaturated carboxylic acids or their anhydrides, unsaturated sulfonic acids, unsaturated phosphonic acids, etc. can be mentioned. Specific examples of the group having an ethylenically unsaturated bond include a vinyl group and a (meth)acryloyloxy group. From the viewpoint of the degree of freedom of the monomer blending ratio, the (meth)acryloyloxy group is preferred. Specifically, (meth)acrylic acid, α-bromo(meth)acrylic acid, β-furyl(meth)acrylic acid, crotonic acid, propiolic acid, cinnamic acid, α-cyanocinnamic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and other unsaturated carboxylic acids or their anhydrides; 2-acrylamido-2-methylpropanesulfonic acid, tert-butylacrylamidosulfonic acid, p-styrenesulfonic acid and other unsaturated sulfonic acids; vinylphosphonic acid and other unsaturated phosphonic acids; etc. can be mentioned. Among them, from the viewpoint of developability as a photosensitive resin composition, (meth)acrylic acid is preferred. These monomers (ma-2) may be used alone or in combination of two or more.

[0039] "Structural unit (a-4) derived from other ethylenically unsaturated compound (ma-4)" The structural unit (a-4) is a structural unit derived from other ethylenically unsaturated compounds (ma-4) (hereinafter also simply referred to as "monomer (ma-4)") other than the structural unit (a-1) and the structural unit (a-2). The monomer (ma-4) does not have the group represented by the above formula (1) and an acid group, and is not particularly limited as long as it is a compound copolymerizable with the monomer (ma-1) and the monomer (ma-2). Specific examples include aromatic vinyl compounds, cyclic olefins having a norbornene structure, dienes, (meth)acrylic acid esters, (meth)acrylic acid amides, vinyl compounds, unsaturated dicarboxylic acid diesters, monomer maleimides, glycidyl (meth)acrylate, (meth)acrylanilide, (meth)acrylonitrile, acrolein, and the like. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-vinyltoluene, p-vinyltoluene, o-chlorostyrene, m-chlorostyrene, methoxystyrene, p-nitrostyrene, p-cyanostyrene, p-acetylaminostyrene, and the like. Examples of cyclic olefins having a norbornene structure include norbornene (bicyclo[2.2.1]hept-2-ene), 5-methylbicyclo[2.2.1]hept-2-ene, tetracyclo[4.4.0.1 2,5 .1 7,10 dodeca-3-ene, 8-ethyltetracyclo[4.4.0.1 2,5 .1 7,10 dodeca-3-ene, dicyclopentadiene, tricyclo[5.2.1.0 2,6 dec-8-ene, tricyclo[4.4.0.1 2,5 undeca-3-ene, tricyclo[6.2.1.0 1,8 undeca-9-ene, tetracyclo[4.4.0.1 2,5 .1 7,10 .0 1,6 dodeca-3-ene, 8-ethylidene tetracyclo[4.4.0.1 2,5 .1 7,12 dodeca-3-ene, pentacyclo[6.5.1.1 3,6 .0 2,7 .0 9,13 pentadeca-4-ene, and the like. Examples of dienes include butadiene, isoprene, chloroprene, and the like. Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, benzyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, rosin (meth)acrylate, norbornyl (meth)acrylate, 5-ethylnorbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl oxyethyl acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 1,1,1-trifluoroethyl (meth)acrylate, perfluoroethyl (meth)acrylate, perfluoro-n-propyl (meth)acrylate, 3-(N,N-dimethylamino)propyl (meth)acrylate, triphenylmethyl (meth)acrylate, phenyl (meth)acrylate, cumyl (meth)acrylate, 4-phenoxyphenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol mono (meth)acrylate, biphenyloxyethyl (meth)acrylate, naphthalene (meth)acrylate, anthracene (meth)acrylate, ethoxylated phenyl (meth)acrylate, and the like. Examples of (meth)acrylamides include (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, anthracenyl (meth)acrylamide, and the like. Examples of vinyl compounds include vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, N-vinylpyrrolidone, vinylpyridine, vinyl acetate, vinyltoluene, and the like. Examples of the unsaturated dicarboxylic acid diesters include diethyl citraconate, diethyl maleate, diethyl fumarate, diethyl itaconate, and the like. Examples of the monomer maleimide include N-phenylmaleimide, N-cyclohexylmaleimide, N-laurylmaleimide, N-(4-hydroxyphenyl)maleimide, and the like. Among them, from the viewpoint of increasing the refractive index of the resin cured film, it is preferable to use a compound having a high refractive index, and it is more preferable to use a compound having a refractive index of 1.55 or more when it is made into a homopolymer. It is even more preferable to use hydroxyphenyl (meth)acrylate, 1-naphthalenemethyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, N-vinylcarbazole, or tribromophenyl acrylate. These monomers (ma-4) may be used alone or in combination of two or more.

[0040] [Ratio of Structural Units of Alkaline-Soluble Resin (A-1)] When the total of the structural units constituting the alkaline-soluble resin (A-1) is 100 mol%, the content ratio of the structural unit (a-1) is preferably 10 mol% or more, more preferably 30 mol% or more, and even more preferably 50 mol% or more. When the total of the structural units constituting the alkaline-soluble resin (A-1) is 100 mol%, the content ratio of the structural unit (a-1) is preferably 95 mol% or less, more preferably 85 mol% or less, and even more preferably 80 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-1) is 10 mol% or more, the refractive index of the resin cured film will be high. When the content ratio of the structural unit (a-1) is 95 mol% or less, the content of the structural unit (a-2) can be sufficiently ensured, and the developability of the photosensitive resin composition is good.

[0041] When the total of the structural units constituting the alkali-soluble resin (A-1) is 100 mol%, the content ratio of the structural unit (a-2) is preferably 5 mol% or more, more preferably 10 mol% or more, and still more preferably 15 mol% or more. When the total of the structural units constituting the alkali-soluble resin (A-1) is 100 mol%, the content ratio of the structural unit (a-2) is preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, and even more preferably 40 mol% or less. Any combination of these lower and upper limits may be used. When the content ratio of the structural unit (a-2) is 5 mol% or more, the developability of the photosensitive resin composition is good. When the content ratio of the structural unit (a-2) is 90 mol% or less, the content of the structural unit (a-1) can be sufficiently ensured, and the refractive index of the resin cured film becomes high.

[0042] When the structural unit (a-4) is contained, when the total of the structural units constituting the alkali-soluble resin (A-1) is 100 mol%, the content ratio of the structural unit (a-4) is preferably 1 mol% or more, more preferably 5 mol% or more, and still more preferably 10 mol% or more. When the total of the structural units constituting the alkali-soluble resin (A-1) is 100 mol%, the content ratio of the structural unit (a-4) is preferably 50 mol% or less, more preferably 40 mol% or less, and still more preferably 30 mol% or less. Any combination of these lower and upper limits may be used. When the content ratio of the structural unit (a-4) is 1 mol% or more, the desired functions can be imparted to the photosensitive resin composition. When the content ratio of the structural unit (a-4) is 50 mol% or less, the contents of the structural unit (a-1) and the structural unit (a-2) can be sufficiently ensured, the developability of the photosensitive resin composition is good, and the refractive index of the resin cured film becomes high.

[0043] In this specification, the ratio of each structural unit of the alkali-soluble resin (A1) is a theoretical value calculated from the charged amount of the raw materials (each monomer) used to introduce each structural unit into the resin (the same applies to the alkali-soluble resins (A2) to (A4) described later). In the following method for producing the alkali-soluble resin (A1), the range of the blending ratio of the raw materials for synthesizing the resin is the same as the preferable range of the content ratio of each of the above structural units (the same applies to the alkali-soluble resins (A2) to (A4) described later).

[0044] 〔Method for Producing Alkali-Soluble Resin (A-1)〕 The copolymerization reaction can be carried out in the presence or absence of a polymerization solvent according to a radical polymerization method known in the art. For example, after dissolving the above monomers in a polymerization solvent, a polymerization initiator may be added to the solution, and the polymerization reaction may be carried out at 50 to 100 °C for 1 to 20 hours.

[0045] The polymerization initiator that can be used in this copolymerization reaction is not particularly limited, and examples thereof include azobisisobutyronitrile, azobisisovaleronitrile, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, and the like. These polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator used is generally 0.5 to 20 parts by mass, preferably 1.0 to 10 parts by mass, when the total charged amount of the monomers is 100 parts by mass.

[0046] As the solvent used in the copolymerization reaction, the same solvents as the solvent (D) described later can be used. In addition, propylene glycol monoaryl ether, 1,3-propanediol monoalkyl ether, 1,3-butanediol monoalkyl ether, 1,4-butanediol monoalkyl ether, glycerin monoalkyl ether, glycerin dialkyl ether, methanol, ethanol, propanol, C5-6 cycloalkanediol, C 5-6Examples thereof include cycloalkanedimethanol, ethyl lactate, and diacetone alcohol. These solvents may be used alone or in combination of two or more.

[0047] [Alkali-soluble resin (A-2)] The alkali-soluble resin (A-2) is a first modified copolymer in which a compound having a group reactive with an epoxy group and an ethylenically unsaturated group is further added to a part of the epoxy groups of a copolymer containing a structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) (hereinafter, also simply referred to as "structural unit (a-1)") and a structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group, and a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by the ring-opening of the epoxy groups. The copolymer containing the structural unit (a-1) and the structural unit (a-3) is a copolymer of an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) and an ethylenically unsaturated compound (ma-3) having an epoxy group. The alkali-soluble resin (A-1) may optionally contain a structural unit (a-4) derived from another ethylenically unsaturated compound (ma-4) (hereinafter, also simply referred to as "structural unit (a-4)"). That is, the alkali-soluble resin (A-1) may be a copolymer with another ethylenically unsaturated compound (ma-4). By using the alkali-soluble resin (A-2) in the photosensitive resin composition described below, a photosensitive resin composition excellent in developability and storage stability can be obtained, and a resin cured film having a higher refractive index can be obtained. The alkali-soluble resin (A-2) can easily introduce the group represented by the above formula (1) by the copolymerization reaction of the monomer containing the compound (ma-1), and can easily adjust the introduction amount of the group represented by the above formula (1). Therefore, it is advantageous for controlling the refractive index. Furthermore, since the alkali-soluble resin (A-2) has an ethylenically unsaturated group introduced therein, it has good compatibility with the reactive diluent (B). In addition, since the amount of carboxyl groups introduced into the alkali-soluble resin (A-2) can be adjusted according to the addition amount of the polybasic acid or its anhydride, the developability as a photosensitive resin composition is good.

[0048] "Structural unit (a-1) derived from the ethylenically unsaturated compound (ma-1) having the group represented by the above formula (1)" The structural unit (a-1) is a structural unit derived from the ethylenically unsaturated compound (ma-1) having the group represented by the above formula (1) (hereinafter, also simply referred to as "monomer (ma-1)"). Specific examples and preferred ranges of the structural unit (a-1) and the monomer (ma-1) are the same as those used for the alkali-soluble resin (A-1).

[0049] "Structural unit (a-3) derived from the ethylenically unsaturated compound (ma-3) having an epoxy group" "Structural unit (a-3) derived from the ethylenically unsaturated compound (ma-3) having an epoxy group" The structural unit (a-3) is a structural unit derived from an ethylenically unsaturated compound (ma-3) having an epoxy group (hereinafter also simply referred to as "monomer (ma-3)"). The structural unit (a-3) has no group and acid group represented by the above formula (1), and is not particularly limited as long as it has an epoxy group. For specific examples and preferred ranges of the structural unit (a-3) and the monomer (ma-3), the same ones as those of the ethylenically unsaturated compound having an epoxy group that generates the monomer (ma-1), which is a constituent monomer of the alkali-soluble resin (A-1), can be used. When the alkali-soluble resin (A-2) has the structural unit (a-3), it becomes a reaction point for introducing an ethylenically unsaturated group, and a photosensitive resin composition having good developability can be obtained. In addition, the epoxy group remaining in the alkali-soluble resin (A-2) without the introduction of the ethylenically unsaturated group assists heat curing by crosslinking with the carboxy group introduced into the alkali-soluble resin (A-2), so that low-temperature curability as a photosensitive resin composition can be imparted. Therefore, even when a base material with low heat resistance is used, a photosensitive resin composition having good curability can be obtained.

[0050] "Structural unit (a-4) derived from other ethylenically unsaturated compound (ma-4)" The structural unit (a-4) is a structural unit derived from other ethylenically unsaturated compound (ma-4) (hereinafter also simply referred to as "monomer (ma-4)") other than the structural unit (a-1) and the structural unit (a-3). The monomer (ma-4) has no group, acid group, and epoxy group represented by the above formula (1), and is not particularly limited as long as it is a compound copolymerizable with the monomer (ma-1) and the monomer (ma-3). For specific examples and preferred ranges of the structural unit (a-4) and the monomer (ma-4), they are the same as those used for the alkali-soluble resin (A-1).

[0051] "Compound having a group reactive with an epoxy group and an ethylenically unsaturated group" The alkali-soluble resin (A-2) has a compound having a group reactive with an epoxy group and an ethylenically unsaturated group further added to a part of the epoxy groups of the structural unit (a-3). From the viewpoint of ease of synthesis, the group reactive with an epoxy group is preferably a carboxy group. The refractive index of the alkali-soluble resin (A-2) can be adjusted by adjusting the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group to the epoxy groups of the structural unit (a-3). Further, the amount of the ethylenically unsaturated group introduced into the alkali-soluble resin (A-2) can be adjusted, and the photocurability and developability as a photosensitive resin composition can be adjusted.

[0052] As specific examples of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group, those exemplified for the monomer (ma-2), which is a constituent monomer of the alkali-soluble resin (A-1), can be used. Among them, (meth)acrylic acid is preferable from the viewpoint of ease of synthesis.

[0053] "Polybasic acid or its anhydride" The polybasic acid or its anhydride is a compound having two or more carboxy groups or its anhydride. In the alkali-soluble resin (A-2), a compound having a group reactive with an epoxy group and an ethylenically unsaturated group is added to the epoxy groups of the structural unit (a-3), and a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by ring-opening of the epoxy groups to introduce carboxy groups. Since the alkali-soluble resin (A-2) can adjust the amount of carboxy groups introduced by the polybasic acid or its anhydride, the developability as a photosensitive resin composition can be adjusted to a desired range. Examples of the polybasic acid include adipic acid, itaconic acid, succinic acid, oxalic acid, malonic acid, phthalic acid, fumaric acid, maleic acid, glutaric acid, tartaric acid, glutamic acid, sebacic acid, etc. Examples of the polybasic acid anhydride include tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, succinic anhydride, cyclohexanetricarboxylic anhydride, etc. These compounds may be used alone or in combination of two or more. Among them, from the viewpoint of the hardness of the cured film, a polybasic acid anhydride having an alicyclic structure is preferable, and maleic anhydride, itaconic anhydride, ethylmaleic anhydride, methylitaconic anhydride, chloromaleic anhydride, citraconic anhydride, 2-norbornene-5,6-dicarboxylic anhydride, 4-[2-(methacryloyloxy)ethoxycarbonyl]phthalic anhydride, succinic anhydride, tetrahydrophthalic anhydride, cyclohexanetricarboxylic anhydride are more preferable, and tetrahydrophthalic anhydride and cyclohexanetricarboxylic anhydride are even more preferable from the viewpoint of increasing the introduction amount of carboxy groups to improve low-temperature curability.

[0054] 〔Ratio of structural units of the alkali-soluble resin (A-2)〕 When the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol%, the content ratio of the structural unit (a-1) is preferably 10 mol% or more, more preferably 30 mol% or more, and even more preferably 50 mol% or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol%, the content ratio of the structural unit (a-1) is preferably 95 mol% or less, more preferably 85 mol% or less, and even more preferably 80 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-1) is 10 mol% or more, the refractive index of the resin cured film becomes high. When the content ratio of the structural unit (a-1) is 95 mol% or less, the content of the structural unit (a-3), the introduction amount of the ethylenically unsaturated group, and the introduction amount of the carboxy group can be sufficiently ensured, and the photocurability and developability as the photosensitive resin composition are good.

[0055] When the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol%, the content ratio of the structural unit (a-3) is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 15 mol% or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol%, the content ratio of the structural unit (a-3) is preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, and even more preferably 40 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-3) is 5 mol% or more, the introduction amount of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group can be sufficiently ensured, and the photocurability as a photosensitive resin composition is good. In addition, the addition amount of the polybasic acid or its anhydride can be ensured, and the introduction amount of the carboxy group can be sufficiently ensured, so the developability as a photosensitive resin composition is good. When the content ratio of the structural unit (a-3) is 90 mol% or less, the content of the structural unit (a-1) can be sufficiently ensured, and the refractive index of the resin cured film becomes high.

[0056] When the structural unit (a-4) is contained, when the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol%, the content ratio of the structural unit (a-4) is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more. When the total of the structural units constituting the alkali-soluble resin (A-2) is 100 mol%, the content ratio of the structural unit (a-4) is preferably 50 mol% or less, more preferably 40 mol% or less, still more preferably 30 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-4) is 1 mol% or more, desired functions can be imparted to the photosensitive resin composition. When the content ratio of the structural unit (a-4) is 50 mol% or less, the contents of the structural unit (a-1) and the structural unit (a-3) can be sufficiently ensured, the developability of the photosensitive resin composition is good, and the refractive index of the resin cured film is high.

[0057] When the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol, the content ratio of the structural unit derived from the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is preferably 1 mol or more, more preferably 5 mol or more, still more preferably 10 mol or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol, the content ratio of the structural unit derived from the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is preferably 80 mol or less, more preferably 60 mol or less, still more preferably 40 mol or less. Even more preferably, it is 30 mol or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit derived from the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is 1 mol or more, the photocurability of the photosensitive resin composition becomes high. When the content ratio of the structural unit derived from the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is 80 mol or less, the residual raw materials during the synthesis of the alkali-soluble resin (A-2) can be suppressed, and the developability of the photosensitive resin composition can be improved.

[0058] The addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group to the number of moles of the epoxy group derived from the structural unit (a-3) is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more. The addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group with respect to the number of moles of the epoxy group derived from the structural unit (a-3) is preferably 90 mol% or less, more preferably 85 mol% or less, and still more preferably 80 mol% or less. Any combination of these lower and upper limits may be used. When the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is 10 mol% or more, the photocurability as a photosensitive resin composition is good. Further, by adjusting the amount of the epoxy group contained in the alkali-soluble resin (A-2), good storage stability can be obtained. When the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is 90 mol% or less, the residual raw materials in the synthesis of the alkali-soluble resin (A-2) can be suppressed, and the developability as a photosensitive resin composition can be improved. Further, by adjusting the amount of the epoxy group contained in the alkali-soluble resin (A-2), low-temperature curability can be imparted.

[0059] The content ratio of the structural unit derived from a polybasic acid or its anhydride is preferably 1 mol or more, more preferably 5 mol or more, and still more preferably 10 mol or more when the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol. The content ratio of the structural unit derived from a polybasic acid or its anhydride is preferably 70 mol or less, more preferably 50 mol or less, and still more preferably 30 mol or less when the total of the structural units constituting the main chain of the alkali-soluble resin (A-2) is 100 mol. Any combination of these lower and upper limits may be used. When the content ratio of the structural unit derived from a polybasic acid or its anhydride is 1 mol or more, the developability as a photosensitive resin composition is good. When the content ratio of the structural unit derived from a polybasic acid or its anhydride is 70 mol or less, the residual raw materials in the synthesis of the alkali-soluble resin (A-2) can be suppressed, and the development residue as a photosensitive resin composition can be reduced. Further, the storage stability as a photosensitive resin composition is good.

[0060] The addition rate of the polybasic acid or its anhydride to the number of moles of the hydroxy group possessed by the precursor of the alkali-soluble resin (A-2) is preferably 1 mol% or more, more preferably 10 mol% or more, and still more preferably 25 mol% or more. The addition rate of the polybasic acid or its anhydride to the number of moles of the hydroxy group possessed by the precursor of the alkali-soluble resin (A-2) is preferably 90 mol% or less, more preferably 75 mol% or less, and still more preferably 60 mol% or less. Any combination of these lower and upper limits may be used. The number of moles of the hydroxy group possessed by the precursor of the alkali-soluble resin (A-2) means, in addition to the hydroxy group generated by the ring-opening of the epoxy group when a compound having a group reactive with the epoxy group and an ethylenically unsaturated group is added to the epoxy group derived from the structural unit (a-3), when the structural unit (a-1) and optionally contained structural unit (a-4) have hydroxy groups, it is the total number of moles including these hydroxy groups. When the addition rate of the polybasic acid or its anhydride is 1 mol% or more, the developability as a photosensitive resin composition is good. When the addition rate of the polybasic acid or its anhydride is 90 mol% or less, the residual raw materials during the synthesis of the alkali-soluble resin (A-2) can be suppressed, and the development residue as a photosensitive resin composition can be reduced. Also, the storage stability as a photosensitive resin composition is good.

[0061] 〔Method for producing alkali-soluble resin (A-2)〕 The copolymerization reaction for obtaining the alkali-soluble resin (A-2) may be carried out in the same manner as the method for producing the alkali-soluble resin (A-1). A method for adding a compound having a group reactive with an epoxy group and an ethylenically unsaturated group or a polybasic acid or its anhydride to a copolymer of an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1), an ethylenically unsaturated compound containing an epoxy group (ma-3), and, if necessary, another ethylenically unsaturated compound (ma-4) that may be used, can use a known addition reaction. For example, after adding a catalyst to a copolymer solution of an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1), an ethylenically unsaturated compound containing an epoxy group (ma-3), and, if necessary, another ethylenically unsaturated compound (ma-4) that may be used, the compound to be added is added, and the addition reaction is carried out under the conditions of room temperature to 150 °C, preferably 50 to 120 °C. Specific examples of the catalyst include tertiary amino groups such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, phosphorus compounds such as triphenylphosphine, and organometallic compounds such as chromium and tin compounds.

[0062] [Alkali-soluble resin (A-3)] The alkali-soluble resin (A-3) is a second modified copolymer in which a compound represented by the following formula (2) is added to a part of the epoxy groups of a copolymer containing a structural unit (a-2) having an acid group derived from an ethylenically unsaturated compound (ma-2) having an acid group and a structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group. The copolymer containing the structural unit (a-2) and the structural unit (a-3) is a copolymer containing an ethylenically unsaturated compound (ma-2) having an acid group and an ethylenically unsaturated compound (ma-3) having an epoxy group.

[0063] [Chemical formula] (In the formula, R 2 is -O-, -S-, or -N(R 5 )-, R 4 is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R 12 is -OH, -SH, or -NHR 5and R 5 is H, an alkyl group, or an alkoxy group, and p is an integer of 0 to 4.)

[0064] The alkali-soluble resin (A-3) may contain, if necessary, a structural unit (a-4) derived from another ethylenically unsaturated compound (ma-4) (hereinafter, also simply referred to as "structural unit (a-4)").

[0065] The alkali-soluble resin (A-3) may, if necessary, be a third modified copolymer in which a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by ring-opening of the epoxy groups derived from the ethylenically unsaturated compound (ma-3) having an epoxy group.

[0066] By using the alkali-soluble resin (A-3), a resin cured film having particularly good transparency and a higher refractive index can be obtained. Since the addition rate of the compound represented by the above formula (2) and the addition rate of the polybasic acid or its anhydride used as necessary can be appropriately adjusted for the alkali-soluble resin (A-1), the developability as a photosensitive resin composition and the refractive index as a resin composition can be adjusted to a desired range. In addition, since crosslinking due to thermosetting between the acid group of the structural unit (a-2) and the epoxy group of the structural unit (a-3) also proceeds, low-temperature curability can be imparted to the photosensitive resin composition.

[0067] "Structural unit (a-2) having an acid group" The structural unit (a-2) is a structural unit derived from an ethylenically unsaturated compound (ma-2) having an acid group (hereinafter, also simply referred to as "monomer (ma-2)"). The structural unit (a-2) does not have the group represented by the above formula (1) and is not particularly limited as long as it has an acid group. Specific examples and preferred ranges of the structural unit (a-2) and the monomer (ma-2) are the same as those used for the alkali-soluble resin (A-1). Since the alkali-soluble resin (A-3) has the structural unit (a-2), good developability can be obtained as a photosensitive resin composition.

[0068] "Structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group" The structural unit (a-3) is a structural unit derived from an ethylenically unsaturated compound (ma-3) having an epoxy group (hereinafter also simply referred to as "monomer (ma-3)"). The structural unit (a-3) has no group and acid group represented by the above formula (1), and is not particularly limited as long as it has an epoxy group. For specific examples and preferred ranges of the structural unit (a-3) and the monomer (ma-3), the same ones as those of the ethylenically unsaturated compound having an epoxy group that forms the monomer (ma-1), which is a constituent monomer of the alkali-soluble resin (A-1), can be used. By the alkali-soluble resin (A-3) having the structural unit (a-3), it becomes a reaction point for introducing the group represented by the above formula (1), and a resin cured film having a high refractive index can be obtained. Further, the epoxy group remaining in the alkali-soluble resin (A-3) without the introduction of the group represented by the above formula (1) assists thermosetting by crosslinking with the structural unit (a-2), so that low-temperature curability as a photosensitive resin composition can be imparted. Therefore, even when a base material having low heat resistance is used, a photosensitive resin composition having good curability can be obtained.

[0069] "Structural unit (a-4) derived from other ethylenically unsaturated compound (ma-4)" The structural unit (a-4) is a structural unit derived from other ethylenically unsaturated compound (ma-4) (hereinafter also simply referred to as "monomer (ma-4)") other than the structural unit (a-2) and the structural unit (a-3). The monomer (ma-4) has no group, acid group, and epoxy group represented by the above formula (1), and is not particularly limited as long as it is a compound copolymerizable with the monomer (ma-2) and the monomer (ma-3). For specific examples and preferred ranges of the structural unit (a-4) and the monomer (ma-4), they are the same as those used for the alkali-soluble resin (A-1).

[0070] "Compound represented by formula (2)" As the compound represented by the above formula (2), specific examples and preferred ranges similar to those of the "compound represented by the above formula (2)" that produce monomer (ma-1), which is a constituent monomer of the alkali-soluble resin (A-1), can be used. By adjusting the addition ratio when adding the compound represented by the above formula (2) to a part of the epoxy groups of the structural unit (a-3) of the alkali-soluble resin (A-3), the refractive index of the alkali-soluble resin (A-3) can be adjusted, and the refractive index of the resin cured film can be adjusted to a desired range.

[0071] "Polybasic acid or its anhydride" As the polybasic acid or its anhydride, specific examples and preferred ranges similar to those of the polybasic acid or its anhydride described in the item of the alkali-soluble resin (A-2) can be used. In the alkali-soluble resin (A-3), the compound represented by the above formula (2) is added to the epoxy group of the structural unit (a-3), and a polybasic acid or its anhydride can be further added to a part of the hydroxy groups generated by the ring-opening of the epoxy group to introduce a carboxy group. Since the alkali-soluble resin (A-3) can adjust the amount of carboxy groups introduced by the polybasic acid or its anhydride, the developability of the photosensitive resin composition can be adjusted to a desired range.

[0072] [Ratio of the structural unit of the alkali-soluble resin (A-3)] When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol%, the content ratio of the structural unit (a-2) is preferably 5 mol% or more, more preferably 10 mol% or more, and still more preferably 15 mol% or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol%, the content ratio of the structural unit (a-2) is preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, and even more preferably 40 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-2) is 5 mol% or more, the developability as a photosensitive resin composition is good. When the content ratio of the structural unit (a-2) is 90 mol% or less, the content of the structural unit (a-3) can be sufficiently ensured, and the introduction amount of the compound represented by the above formula (2) can be ensured, so that the refractive index of the resin cured film becomes high.

[0073] When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol%, the content ratio of the structural unit (a-3) is preferably 10 mol% or more, more preferably 30 mol% or more, and still more preferably 50 mol% or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol%, the content ratio of the structural unit (a-3) is preferably 95 mol% or less, more preferably 90 mol% or less, and still more preferably 85 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-3) is 10 mol% or more, the introduction amount of the compound represented by the above formula (2) can be ensured, so that the refractive index of the resin cured film becomes high. When the content ratio of the structural unit (a-3) is 95 mol% or less, the content of the structural unit (a-2) can be sufficiently ensured, and the developability as a photosensitive resin composition is good.

[0074] When the structural unit (a-4) is contained, the content ratio of the structural unit (a-4) is based on 100 mol% of the total of the structural units constituting the main chain of the alkali-soluble resin (A-3). Preferably it is 1 mol% or more, more preferably 5 mol% or more, and still more preferably 10 mol% or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol%, the content ratio of the structural unit (a-4) is preferably 50 mol% or less, more preferably 40 mol% or less, and still more preferably 30 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit (a-4) is 1 mol% or more, desired functions can be imparted to the photosensitive resin composition. When the content ratio of the structural unit (a-4) is 50 mol% or less, the contents of the structural unit (a-2) and the structural unit (a-3) can be sufficiently ensured, the developability of the photosensitive resin composition is good, and the refractive index of the resin cured film is high.

[0075] When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol, the content ratio of the structural unit derived from the compound represented by the above formula (2) is preferably 5 mol or more, more preferably 10 mol or more, and still more preferably 15 mol or more. When the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol, the content ratio of the structural unit derived from the compound represented by the above formula (2) is preferably 90 mol or less, more preferably 80 mol or less, and still more preferably 70 mol or less. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit derived from the compound represented by the above formula (2) is 5 mol or more, the refractive index of the resin cured film is high. When the content ratio of the structural unit derived from the compound represented by the above formula (2) is 90 mol or less, the residual raw materials in the synthesis of the alkali-soluble resin (A-3) can be suppressed, and the developability of the photosensitive resin composition can be improved.

[0076] The addition rate of the compound represented by the above formula (2) to the number of moles of the epoxy group derived from the structural unit (a-3) is preferably 10 mol% or more, more preferably 20 mol% or more, and still more preferably 30 mol% or more. The addition rate of the compound represented by the above formula (2) to the number of moles of the epoxy group derived from the structural unit (a-3) is preferably 90 mol% or less, more preferably 85 mol% or less, and still more preferably 80 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the addition rate of the compound represented by the above formula (2) is 10 mol% or more, the refractive index of the resin cured film becomes high. Further, by adjusting the amount of epoxy groups contained in the alkali-soluble resin (A-3), good storage stability can be obtained. When the addition rate of the compound represented by the above formula (2) is 90 mol% or less, the residual raw materials during the synthesis of the alkali-soluble resin (A-3) can be suppressed, and the developability as a photosensitive resin composition can be improved. Further, by adjusting the amount of epoxy groups contained in the alkali-soluble resin (A-3), low-temperature curability can be imparted.

[0077] When containing a structural unit derived from a polybasic acid or its anhydride, the content ratio of the structural unit derived from a polybasic acid or its anhydride is preferably 1 mol or more, more preferably 5 mol or more, and still more preferably 10 mol or more when the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol. The content ratio of the structural unit derived from a polybasic acid or its anhydride is preferably 70 mol or less, more preferably 60 mol or less, and still more preferably 50 mol or less when the total of the structural units constituting the main chain of the alkali-soluble resin (A-3) is 100 mol. Any combination of these lower limit values and upper limit values may be used. When the content ratio of the structural unit derived from a polybasic acid or its anhydride is 1 mol or more, the developability as a photosensitive resin composition can be further improved. When the content ratio of the structural unit derived from a polybasic acid or its anhydride is 70 mol or less, the residual raw materials during the synthesis of the alkali-soluble resin (A-3) can be suppressed, and the development residue as a photosensitive resin composition can be reduced. Further, the storage stability as a photosensitive resin composition is good.

[0078] When containing a structural unit derived from a polybasic acid or its anhydride, the addition rate of the polybasic acid or its anhydride to the number of moles of the structural unit derived from the compound represented by the above formula (2) is preferably 1 mol% or more, more preferably 10 mol% or more, and still more preferably 25 mol% or more. The addition rate of the polybasic acid or its anhydride to the number of moles of the structural unit derived from the compound represented by the above formula (2) is preferably 90 mol% or less, more preferably 75 mol% or less, and still more preferably 60 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the addition rate of the polybasic acid or its anhydride is 1 mol% or more, the developability as a photosensitive resin composition can be further improved. When the addition rate of the polybasic acid or its anhydride is 90 mol% or less, the residual raw materials in the synthesis of the alkali-soluble resin (A-3) can be suppressed, and the development residue as a photosensitive resin composition can be reduced. Also, the storage stability as a photosensitive resin composition is good.

[0079] 〔Manufacturing method of alkali-soluble resin (A-3)〕 The copolymerization reaction for obtaining the alkali-soluble resin (A-3) may be carried out in the same manner as the manufacturing method of the alkali-soluble resin (A-1). As a method of adding the compound represented by the above formula (2) or, if necessary, a polybasic acid or its anhydride to a copolymer of an acid group-containing ethylenically unsaturated compound (ma-2), an epoxy group-containing ethylenically unsaturated compound (ma-3), and other ethylenically unsaturated compounds (ma-4) that may be used as necessary, known addition reactions can be used. For example, after adding a catalyst to a copolymer solution of an acid group-containing ethylenically unsaturated compound (ma-2), an epoxy group-containing ethylenically unsaturated compound (ma-3), and other ethylenically unsaturated compounds (ma-4) that may be used as necessary, the compound to be added is added, and the addition reaction is carried out under the conditions of room temperature to 150 °C, preferably 50 to 120 °C. Specific examples of the catalyst include tertiary amino groups such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, phosphorus compounds such as triphenylphosphine, and organometallic compounds such as chromium and tin.

[0080] [Alkali-soluble resin (A-4)] The alkali-soluble resin (A-4) is a modified epoxy resin in which a compound represented by the following formula (2) is added to a part of the epoxy groups of the epoxy resin, and a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by the ring-opening of the epoxy groups.

[0081] [Chemical formula] (In the formula, R 2 is -O-, -S-, or -N(R 5 )-, R 4 is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R 12 is -OH, -SH, or -NHR 5 and R 5 is H, an alkyl group, or an alkoxy group, and p is an integer from 0 to 4.)

[0082] The alkali-soluble resin (A-4) may further have a compound having a group reactive with an epoxy group and an ethylenically unsaturated group added to a part of the epoxy groups of the epoxy resin, if necessary.

[0083] By using the alkali-soluble resin (A-4), a resin cured film having a particularly high refractive index and a small birefringence can be obtained, and a photosensitive resin composition having both developability can be obtained.

[0084] "Epoxy resin" The epoxy resin is not particularly limited as long as it has an epoxy group. Specifically, it is a novolak-type epoxy resin obtained by epoxidizing a novolak resin obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc. and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc. with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc. under an acidic catalyst (phenol novolak-type epoxy resin, orthocresol novolak-type epoxy resin, etc.); A triphenylmethane-type epoxy resin obtained by epoxidizing a triphenylmethane-type phenolic resin obtained by condensing or co-condensing the above phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc. under an acidic catalyst; A copolymer-type epoxy resin obtained by epoxidizing a novolak resin obtained by co-condensing the above phenolic compound and naphthol compound with an aldehyde compound under an acidic catalyst; A diphenylmethane-type epoxy resin which is a diglycidyl ether of bisphenol A, bisphenol F, etc.; A biphenyl-type epoxy resin which is a diglycidyl ether of an alkyl-substituted or unsubstituted biphenol; A stilbene-type epoxy resin which is a diglycidyl ether of a stilbene-based phenolic compound; A sulfur atom-containing type epoxy resin which is a diglycidyl ether of bisphenol S, etc.; an epoxy resin which is a glycidyl ether of alcohols such as butanediol, polyethylene glycol, polypropylene glycol, etc.; A glycidyl ester-type epoxy resin which is a glycidyl ester of a polyvalent carboxylic acid compound such as phthalic acid, isophthalic acid, tetrahydrophthalic acid, etc.; A glycidyl amine-type epoxy resin obtained by substituting active hydrogen bonded to a nitrogen atom such as aniline, diaminodiphenylmethane, isocyanuric acid, etc. with a glycidyl group; Dicyclopentadiene-type epoxy resin obtained by epoxidizing a co-condensation resin of dicyclopentadiene and a phenolic compound; Alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, which are obtained by epoxidizing olefin bonds in the molecule; Para-xylylene-modified epoxy resin, which is a glycidyl ether of para-xylylene-modified phenolic resin; Meta-xylylene-modified epoxy resin, which is a glycidyl ether of meta-xylylene-modified phenolic resin; Terpene-modified epoxy resin, which is a glycidyl ether of terpene-modified phenolic resin; Dicyclopentadiene-modified epoxy resin, which is a glycidyl ether of dicyclopentadiene-modified phenolic resin; Cyclopentadiene-modified epoxy resin, which is a glycidyl ether of cyclopentadiene-modified phenolic resin; Polycyclic aromatic ring-modified epoxy resin, which is a glycidyl ether of polycyclic aromatic ring-modified phenolic resin; Naphthalene-type epoxy resin, which is a glycidyl ether of a phenolic resin containing a naphthalene ring; Halogenated phenol novolac-type epoxy resin; hydroquinone-type epoxy resin; trimethylolpropane-type epoxy resin; Linear aliphatic epoxy resin obtained by oxidizing an olefin bond with a peracid such as peracetic acid; Aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins; and the like. Furthermore, epoxidized silicone resins, aminophenol type epoxy resins which are glycidyl ethers of aminophenols, etc. can also be cited as epoxy resins. These epoxy resins may be used alone or in combination of two or more. Among these, from the viewpoints of solubility, molecular weight, and high refractive index, dicyclopentadiene type epoxy resins are preferred, novolak type epoxy resins are more preferred, and cresol novolak type epoxy resins are even more preferred.

[0085] The epoxy equivalent of the epoxy resin is not particularly limited. From the viewpoints of the refractive index of the resin cured film and the balance of various properties such as developability as a photosensitive resin composition, the epoxy equivalent of the epoxy resin is preferably 60 g / eq to 1000 g / eq, and more preferably 80 g / eq to 500 g / eq.

[0086] The weight average molecular weight of the epoxy resin is not particularly limited. From the viewpoints of viscosity and developability, the weight average molecular weight of the epoxy resin is preferably 500 to 30000, more preferably 1000 to 10000, and even more preferably 2000 to 5000.

[0087] "Compound represented by formula (2)" For the compound represented by the above formula (2), the same specific examples and preferred ranges as those of the "compound represented by the above formula (2)" that generates monomer (ma-1), which is a constituent monomer of the alkali-soluble resin (A-1), can be used. The alkali-soluble resin (A-4) can adjust the refractive index of the alkali-soluble resin (A-4) by adjusting the addition rate when adding the compound represented by the above formula (2) to a part of the epoxy groups of the epoxy resin, and can adjust the refractive index of the resin cured film to a desired range.

[0088] "Polybasic acid or its anhydride" For the polybasic acid or its anhydride, the same specific examples and preferred ranges as those of the polybasic acid or its anhydride described in the item of the alkali-soluble resin (A-2) can be used. The alkali-soluble resin (A-4) is obtained by adding the compound represented by the above formula (2) to the epoxy group of the epoxy resin, and further adding a polybasic acid or its anhydride to a part of the hydroxy groups generated by the ring-opening of the epoxy group to introduce a carboxy group. Since the alkali-soluble resin (A-4) can adjust the amount of carboxy group introduced by the polybasic acid or its anhydride, the developability as a photosensitive resin composition can be adjusted to a desired range.

[0089] "Compound having a group reactive with an epoxy group and an ethylenically unsaturated group" The alkali-soluble resin (A-4) may further have a compound having a group reactive with an epoxy group and an ethylenically unsaturated group added to a part of the epoxy groups derived from the epoxy resin, if necessary. From the viewpoint of ease of synthesis, the group reactive with an epoxy group is preferably a carboxy group. The alkali-soluble resin (A-4) can adjust the refractive index of the alkali-soluble resin (A-4) by adjusting the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group to the epoxy groups of the epoxy resin. Further, the amount of the ethylenically unsaturated group introduced into the alkali-soluble resin (A-4) can be adjusted, and the photocurability and developability as a photosensitive resin composition can be adjusted.

[0090] As specific examples of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group, those listed in the monomer (ma-2), which is a constituent monomer of the alkali-soluble resin (A-1), can be used, and among them, (meth)acrylic acid is preferable from the viewpoint of ease of synthesis.

[0091] 〔Ratio of structural units of alkali-soluble resin (A-4)〕 The addition rate of the compound represented by the above formula (2) to the number of moles of the epoxy groups derived from the epoxy resin is preferably 10 mol% or more, more preferably 20 mol% or more. More preferably, it is 30 mol% or more. The addition rate of the compound represented by the above formula (2) with respect to the number of moles of epoxy groups derived from the epoxy resin is preferably 90 mol% or less, more preferably 85 mol% or less, and still more preferably 80 mol% or less. Any combination of these lower and upper limits may be used. When the addition rate of the compound represented by the above formula (2) is 10 mol% or more, the refractive index of the resin cured film becomes high. Also, by adjusting the amount of epoxy groups contained in the alkali-soluble resin (A-3), good storage stability can be obtained. When the addition rate of the compound represented by the above formula (2) is 90 mol% or less, the residual raw materials during the synthesis of the alkali-soluble resin (A-4) can be suppressed, and the developability of the photosensitive resin composition can be improved. Also, by adjusting the amount of epoxy groups contained in the alkali-soluble resin (A-4), low-temperature curability can be imparted.

[0092] The addition rate of the polybasic acid or its anhydride with respect to the number of moles of the structural unit derived from the compound represented by the above formula (2) is preferably 10 mol% or more, more preferably 20 mol% or more, and still more preferably 30 mol% or more. The addition rate of the polybasic acid or its anhydride with respect to the number of moles of the structural unit derived from the compound represented by the above formula (2) is preferably 90 mol% or less, more preferably 75 mol% or less, and still more preferably 60 mol% or less. Any combination of these lower and upper limits may be used. When the addition rate of the polybasic acid or its anhydride is 1 mol% or more, the developability of the photosensitive resin composition can be improved. When the addition rate of the polybasic acid or its anhydride is 90 mol% or less, the residual raw materials during the synthesis of the alkali-soluble resin (A-4) can be suppressed, and the development residue of the photosensitive resin composition can be reduced. Also, the storage stability of the photosensitive resin composition is good.

[0093] When having a structural unit derived from a compound having a group reactive with an epoxy group and an ethylenically unsaturated group, the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group with respect to the number of moles of the epoxy groups derived from the epoxy resin is preferably 1 mol% or more, more preferably 5 mol% or more, and still more preferably 10 mol% or more. The addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group with respect to the number of moles of the epoxy groups derived from the epoxy resin is preferably 60 mol% or less, more preferably 40 mol% or less, and still more preferably 30 mol% or less. Any combination of these lower limit values and upper limit values may be used. When the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is 1 mol% or more, the developability as a photosensitive resin composition can be further improved. When the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group is 60 mol% or less, the addition rate of the compound represented by the above formula (2) can be sufficiently ensured, and the refractive index of the resin cured film becomes sufficiently high.

[0094] When having a structural unit derived from a compound having a group reactive with an epoxy group and an ethylenically unsaturated group, the addition rate of the polybasic acid or its anhydride is read as the addition rate with respect to the total number of moles of the structural unit represented by the above formula (2) and the structural unit derived from the compound having a group reactive with an epoxy group and an ethylenically unsaturated group, and it is preferably used at an addition rate within the same range.

[0095] 〔Production method of alkali-soluble resin (A-4)〕 The alkali-soluble resin (A-4) can be produced by adding a compound represented by the following formula (2) to a part of the epoxy groups of the epoxy resin, and, if necessary, a compound having a group reactive with an epoxy group and an ethylenically unsaturated group, and further adding a polybasic acid or its anhydride to a part of the hydroxy groups generated by the ring-opening of the epoxy groups. A method of adding a compound represented by the above formula (2) to an epoxy resin, and, if necessary, a compound having a group reactive with an epoxy group and an ethylenically unsaturated group, and further adding a polybasic acid or its anhydride to the hydroxy group generated by ring-opening of the hydroxy group, a known addition reaction can be used. For example, after adding a catalyst to a solution obtained by mixing an epoxy resin and a solvent, the compound to be added is added, and the addition reaction is carried out under the conditions of room temperature to 150 ° C, preferably 50 to 120 ° C. Specific examples of the catalyst include tertiary amino groups such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, phosphorus compounds such as triphenylphosphine, and organometallic compounds such as chromium and tin.

[0096] (Photosensitive resin composition) The photosensitive resin composition according to an embodiment of the present invention (sometimes referred to as the photosensitive resin composition of this embodiment) contains the alkali-soluble resin (A) of the above-described embodiment, a reactive diluent (B), a photopolymerization initiator (C), and a solvent (D). The photosensitive resin composition contains a colorant (E) if necessary. The photosensitive resin composition of this embodiment is polymerized and cured by light irradiation to form a resin cured film.

[0097] The content of the alkali-soluble resin (A) in the photosensitive resin composition of this embodiment is preferably 10% by mass or more, more preferably 30% by mass or more, and still more preferably 50% by mass or more with respect to 100% by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). Any combination of these lower limit values and upper limit values may be used. The content of the alkali-soluble resin (A) is preferably 90% by mass or less, more preferably 80% by mass or less, and still more preferably 70% by mass or less with respect to 100% by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). Any combination of these lower limit values and upper limit values may be used. When the content ratio of the reactive diluent (A) is within the above range, the developability and photocurability of the photosensitive resin composition become more appropriate.

[0098] [Reactive diluent (B)] The reactive diluent (B) contained in the photosensitive resin composition of the present embodiment may be a low molecular weight compound having an ethylenically unsaturated group such as a vinyl group, an allyl group, or a (meth)acryloyloxy group, and is not particularly limited. For improving curability (reactivity), a reactive diluent having a plurality of ethylenically unsaturated groups (polyfunctional reactive diluent) is preferred. Specific examples of the reactive diluent (B) include aromatic vinyl monomers; polycarboxylic acid monomers such as vinyl acetate and vinyl adipate; monofunctional (meth)acrylates; polyfunctional (meth)acrylates; and triallyl cyanurate.

[0099] Specific examples of the aromatic vinyl monomers include styrene, α-methylstyrene, α-chloromethylstyrene, vinyltoluene, divinylbenzene, diallyl phthalate, and diallyl benzene phosphonate.

[0100] Specific examples of the monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, β-hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate.

[0101] Specific examples of the polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and tri(meth)acrylate of tris(hydroxyethyl) isocyanurate.

[0102] Among these, as the reactive diluent (B), polyfunctional (meth)acrylates are preferred for improving curability (reactivity), and in particular, dipentaerythritol penta(meth)acrylate and / or dipentaerythritol hexa(meth)acrylate are preferred. These reactive diluents (B) may be used alone or in combination of two or more.

[0103] The content of the reactive diluent (B) in the photosensitive resin composition of the present embodiment is preferably 1% by mass or more, more preferably 25% by mass or more, and still more preferably 40% by mass or more with respect to 100% by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). The content of the reactive diluent (B) is preferably 90% by mass or less with respect to 100% by mass in total of the alkali-soluble resin (A) and the reactive diluent (B), more preferably 75% by mass or less, and still more preferably 60% by mass or less. Any combination of these lower limit and upper limit values may be used. When the content ratio of the reactive diluent (B) is within the above range, the viscosity and photocurability of the photosensitive resin composition become more appropriate.

[0104] [Photopolymerization initiator (C)] The photoinitiator (C) is not particularly limited. For example, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, -1-(O-acetoxyoxime); benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether and other benzoins and their alkyl ethers; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4'-(1-t-butyldioxy-1-methylethyl)acetophenone and other acetophenone compounds; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1; 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone and other anthraquinone compounds; xanthone; thioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone and other thioxanthone compounds; ketal compounds such as acetophenone dimethyl ketal, benzyl dimethyl ketal; benzophenone, 4-(1-t-butyldioxy-1-methylethyl)benzophenone, 3,3',4,4'-tetrakis(t-butyldioxycarbonyl)benzophenone and other benzophenone compounds; acylphosphine oxide-based photoinitiators and the like. The photoinitiator (C) may be used alone or in combination of two or more kinds.

[0105] The content of the photoinitiator (C) in the photosensitive resin composition is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and still more preferably 1.0 part by mass or more with respect to 100 parts by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). The content of the photoinitiator (C) in the photosensitive resin composition is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less with respect to 100 parts by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). Any combination of these lower limit and upper limit values may be used. When the content of the photoinitiator (C) is 0.1 part by mass or more, a photosensitive resin composition having good photocurability can be obtained. When the content of the photoinitiator (C) is 30 parts by mass or less, it is possible to prevent the physical properties of the cured product of the photosensitive resin composition from being adversely affected by an excessive amount of the photoinitiator (C).

[0106] [Solvent (D)] Examples of the solvent (D) include hydroxy group-free solvents such as (poly)alkylene 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 monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, 3-methoxy-1-butanol; hydroxy group-containing carboxylic acid esters such as methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate; and hydroxy group-containing solvents such as diethylene glycol; and (poly)alkylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate; ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran; ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone; esters such as methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl ethoxyacetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, ethyl acetate, n-butyl acetate, i-propyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutyrate; aromatic hydrocarbons such as toluene, xylene; and carboxylic acid amides such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide. The solvent (D) may be used alone or in combination of two or more kinds.

[0107] Among these solvents (D), from the viewpoints of availability, cost, and stability during resist production, it is preferable to use an ether. Specifically, it is more preferable to use one or more selected from propylene glycol monomethyl ether acetate, diethylene glycol methyl ethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, and 3-methoxy-1-butanol.

[0108] The content of the solvent (C) in the photosensitive resin composition is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, based on 100 parts by mass in total of the components excluding the solvent (D). The content of the solvent (C) in the photosensitive resin composition is preferably 1,000 parts by mass or less, more preferably 800 parts by mass or less, based on 100 parts by mass in total of the components excluding the solvent (D). Any combination of these lower limit values and upper limit values may be used. When the content of the solvent (C) is 30 parts by mass or more, the viscosity of the photosensitive resin composition can be set within an appropriate range. When the content of the solvent (C) is 1,000 parts by mass or less, the solvent (C) can be easily removed when removing the solvent (C) in the coating film formed by coating the photosensitive resin composition on a substrate.

[0109] [Colorant (E)] The photosensitive resin composition may contain a colorant (E) as necessary. The photosensitive resin composition containing the colorant (E) can be used as a material for a color filter.

[0110] The colorant (E) is not particularly limited as long as it can be dissolved or dispersed in the solvent (D), and examples thereof include dyes and pigments.

[0111] As the dye, from the viewpoints of solubility in the solvent (D) and an alkali developer, interaction with other components in the photosensitive resin composition, heat resistance, etc., it is preferable to use an acidic dye having an acid group such as a carboxy group or a sulfo group, a salt of the acidic dye with a nitrogen compound, a sulfonamide adduct of the acidic dye, etc.

[0112] 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; solvent blue 38, 44, 70; acid chrome violet K; acid Fuchsin; 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 their derivatives and the like. Among these, azo-based, xanthene-based, anthraquinone-based, or phthalocyanine-based acid dyes are preferred. The dyes can be used alone or in combination of two or more.

[0113] Examples of pigments include yellow pigments such as C.I. Pigment 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.; orange pigments such as C.I. Pigment Orange 13, 31, 36, 38, 40, 42, 43, 51, 55, 59, 61, 64, 65, 71, 73, etc.; red pigments such as C.I. Pigment Red 9, 97, 105, 122, 123, 144, 149, 166, 168, 176, 177, 180, 192, 209, 215, 216, 224, 242, 254, 255, 264, 265, etc.; blue pigments such as C.I. Pigment Blue 15, 15:3, 15:4, 15:6, 60, etc.; violet pigments such as C.I. Pigment Violet 1, 19, 23, 29, 32, 36, 38, etc.; green pigments such as C.I. Pigment Green 7, 36, 58, 59, etc.; brown pigments such as C.I. Pigment Brown 23, 25, etc.; black pigments such as C.I. Pigment Black 1, 7, carbon black, titanium black, iron oxide, etc. The pigments can be used alone or in combination of two or more.

[0114] The colorant (E) can be appropriately determined according to, for example, the color of the target coloring pattern (black matrix and pixel). The colorant (E) may be used alone or in combination of two or more. When two or more colorants (E) are used, a combination of a dye and a pigment may be used.

[0115] When a pigment is used as the colorant (E), from the viewpoint of improving the dispersibility of the pigment, a known dispersant may be blended in the photosensitive resin composition. As the dispersant, it is preferable to use a polymer dispersant having excellent dispersion stability over time. Examples of the polymer dispersant include urethane-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. As the polymer dispersant, those commercially available under trade names such as EFKA (manufactured by EFKA CHEMICALS B.V.), Disperbyk (manufactured by BYK CHEMIE), Disparon (manufactured by Kusumoto Chemicals, Ltd.), and SOLSPERSE (manufactured by Lubrizol) may be used. The content of the dispersant may be appropriately set according to the type and amount of the pigment used as the colorant (E).

[0116] The content of the colorant (E) in the photosensitive resin composition is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more with respect to 100 parts by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). The content of the colorant (E) in the photosensitive resin composition is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less with respect to 100 parts by mass in total of the alkali-soluble resin (A) and the reactive diluent (B). Any combination of these lower limit values and upper limit values may be used. When the content of the colorant (E) is 3 parts by mass or more, the effect of containing the colorant (E) becomes remarkable, and a photosensitive resin composition suitable as a material for the colored pattern of the color filter can be obtained. When the content of the colorant (E) is 80 parts by mass or less, the colorant (E) does not hinder the curability of the photosensitive resin composition, and a photosensitive resin composition having good low-temperature curability can be obtained.

[0117] [Other components] In the photosensitive resin composition of one embodiment, in addition to an alkali-soluble resin (A), a reactive diluent (B), a photopolymerization initiator (C), a solvent (D), and an optional colorant (E), known additives such as a coupling agent, a leveling agent, and a thermal polymerization inhibitor may be blended as required. The blending amount of the additive may be in a range that does not inhibit the effects of the present invention and is not particularly limited.

[0118] <Manufacturing method of photosensitive resin composition> The photosensitive resin composition of one embodiment can be manufactured by a method of mixing an alkali-soluble resin (A), a reactive diluent (B), a photopolymerization initiator (C), a solvent (D), and an optional colorant (E) as required using a known mixing device.

[0119] When manufacturing the photosensitive resin composition, as a raw material, the reaction solution in the production of the alkali-soluble resin (A) can be used as it is. In this case, the solvent (D) contained in the reaction solution can be used as part or all of the solvent (D) contained in the photosensitive resin composition or the photosensitive coloring composition.

[0120] Since the photosensitive resin composition contains an alkali-soluble resin (A) containing a group represented by the above formula (1), a resin cured film having a high refractive index can be obtained.

[0121] In addition, the developability of the photosensitive resin composition can be adjusted according to the purpose, and it can be controlled within a desired range in consideration of the balance with the refractive index. From this, a material that achieves both the refractive index of the resin cured film and the developability of the photosensitive resin composition can be obtained.

[0122] The photosensitive resin composition can be suitably used as a material for a color filter.

[0123] From these facts, the photosensitive resin composition is extremely useful as a material for forming members of image display elements such as pixels of color filters, black matrices, color filter protective films, photo spacers, protrusions for liquid crystal alignment, microlenses, and insulating films for touch panels.

[0124] (Resin cured film) The resin cured film of one embodiment of the present invention (sometimes referred to as the resin cured film of this embodiment) is composed of a cured product of a photosensitive resin composition.

[0125] The resin cured film can be produced, for example, by applying a photosensitive resin composition onto a substrate, volatilizing and removing the solvent (D) to form a coating film, exposing the coating film to be photocured, and then performing a baking treatment.

[0126] When forming a resin cured film having a predetermined pattern shape, for example, the following method can be used. That is, a photosensitive resin composition is applied onto a substrate, the solvent (D) is volatilized and removed to form a coating film. Next, the coating film is exposed through a photomask having a predetermined pattern shape to photocure the exposed portion. Then, the unexposed portion of the coating film is developed with an aqueous alkali solution. Thereafter, a baking treatment is performed on the developed coating film to form a resin cured film having a predetermined pattern shape.

[0127] As the coating method of the photosensitive resin composition, the exposure method of the coating film, and the development method when producing the resin cured film, known methods can be used.

[0128] The conditions of the baking treatment performed when producing the resin cured film can be appropriately determined according to the composition of the photosensitive resin composition, the film thickness of the coating film, the material of the substrate, etc. The baking treatment can be performed, for example, at a temperature of 70°C to 250°C. The temperature of the baking treatment is preferably 75°C or higher, more preferably 80°C or higher. When the temperature of the baking treatment is 250°C or lower, it is a condition that materials with low heat resistance can withstand, and it is preferable because discoloration of the photosensitive resin composition can be suppressed.

[0129] The baking treatment carried out when manufacturing the resin cured film can be carried out for, for example, 10 minutes to 4 hours, preferably 20 minutes to 2 hours, and can be appropriately determined according to the composition of the photosensitive resin composition, the temperature of the baking treatment, the film thickness of the coating film, etc.

[0130] The resin cured film is composed of a cured product of the photosensitive resin composition. Therefore, the resin cured film can be manufactured by using a method of baking treatment at a low temperature, and moreover, it has excellent solvent resistance.

[0131] (Color filter) The color filter according to one embodiment of the present invention includes a colored pattern composed of a cured product of a photosensitive resin composition. The color filter contains 10 to 99% by mass of the alkali-soluble resin (A) and 1 to 90% by mass of the reactive diluent (B) with respect to a total of 100% by mass of the alkali-soluble resin (A) and the reactive diluent (B), and with respect to a total of 100 parts by mass of the alkali-soluble resin (A) and the reactive diluent (B), It preferably has a colored pattern composed of a cured product of a photosensitive resin composition containing 0.1 to 30 parts by mass of a photopolymerization initiator (C), 3 to 80 parts by mass of a colorant (E), and 30 to 1,000 parts by mass of a solvent (D) with respect to a total of 100 parts by mass of the components excluding the solvent (D).

[0132] The color filter may include, for example, a substrate, RGB pixels formed thereon, a black matrix formed at the boundary of each pixel, and a protective film formed on the pixels and the black matrix.

[0133] In the color filter, the pixels and the black matrix are colored patterns composed of a cured product of the above photosensitive resin composition. In the color filter, known components can be adopted for the constitution other than the materials of the pixels and the black matrix.

[0134] The substrate used for the color filter is not particularly limited, and a glass substrate, a silicon substrate, a polycarbonate substrate, a polyester substrate, a polyamide substrate, a polyamideimide substrate, a polyimide substrate, an aluminum substrate, a printed wiring board, an array substrate, etc. can be appropriately used according to the application.

[0135] <Method for manufacturing a color filter> Next, an exemplary manufacturing method of the color filter will be described. First, a colored pattern is formed on the substrate. Specifically, a colored pattern that becomes a black matrix formed at the boundary of each pixel and a colored pattern that becomes each RGB pixel are sequentially formed on the substrate by the method shown below.

[0136] The colored pattern can be formed by a photolithography method. Specifically, a photosensitive resin composition is applied on the substrate to form a coating film. Then, the coating film is exposed through a photomask having a predetermined pattern shape to photocure the exposed portion. Next, the unexposed portion of the coating film is developed with an alkaline aqueous solution. Then, by performing a baking treatment on the developed coating film, a colored pattern having a predetermined pattern shape can be formed.

[0137] The application method of the photosensitive resin composition is not particularly limited, and known methods such as a screen printing method, a roll coating method, a curtain coating method, a spray coating method, and a spin coating method can be used.

[0138] In addition, after applying the photosensitive resin composition on the substrate, if necessary, the substrate can be heated using heating means such as a circulation oven, an infrared heater, or a hot plate to volatilize and remove the solvent (D) contained in the coating film. The conditions for heating the substrate to remove the solvent (D) are not particularly limited and can be appropriately set according to the material of the substrate, the composition of the photosensitive resin composition, the film thickness of the coating film, etc. The heating of the substrate can be performed, for example, at a temperature of 50°C to 120°C for 30 seconds to 30 minutes.

[0139] Next, the coating film thus formed is irradiated with active energy rays such as ultraviolet rays and excimer laser light through a negative photomask, partially exposed, and the exposed portion is photocured. The dose of the active energy rays irradiated onto the coating film may be appropriately selected according to the composition of the photosensitive resin composition, etc., for example, 30~2000 mJ / cm 2 can be used. The light source used for exposure is not particularly limited, and a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, etc. can be used.

[0140] The alkaline aqueous solution used for developing the coating film is not particularly limited, but an aqueous solution of an inorganic alkaline compound such as sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide; an aqueous solution of an amine compound such as ethylamine, diethylamine, dimethylethanolamine; an aqueous solution of a quaternary ammonium salt such as sulfate, hydrochloride or p-toluenesulfonate of tetramethylammonium; an aqueous solution of an aniline compound and its salt such as 3-methyl-4-amino-N,N-diethylaniline, 3-methyl-4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfonamidoethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methoxyethylaniline, and their sulfates, hydrochlorides or p-toluenesulfonates; an aqueous solution of a p-phenylenediamine compound and its salt, etc. can be used. In addition, additives such as an antifoaming agent and a surfactant may be added to the alkaline aqueous solution as necessary.

[0141] After developing the coating film using the above alkaline aqueous solution, it is preferable to wash the coating film with water and dry it.

[0142] The conditions of the baking process performed when manufacturing a color filter can be appropriately determined according to the composition of the photosensitive resin composition, the film thickness of the coating film, the material of the substrate, etc. The temperature of the baking process can be, for example, 70°C to 210°C. When the baking temperature is 70°C or higher, good curability can be obtained, and a cured product having excellent solvent resistance can be obtained. The temperature of the baking process is preferably 75°C or higher, more preferably 80°C or higher. When the temperature of the baking process is 210°C or lower, it is preferable because materials with low heat resistance such as substrates with low heat resistance can be used as materials for the color filter.

[0143] The baking process performed when manufacturing a color filter can be carried out, for example, for 10 minutes to 4 hours, preferably for 20 minutes to 2 hours, and can be appropriately determined according to the composition of the photosensitive resin composition, the temperature of the baking process, the film thickness of the coating film, etc.

[0144] The photosensitive resin composition has good photocurability and low-temperature curability. Therefore, when forming a colored pattern using the photosensitive resin composition of one embodiment, when the temperature of the baking process is made the same as when forming a colored pattern using a conventional photosensitive resin composition, the baking time can be shortened, and a color filter can be efficiently formed.

[0145] After forming a colored pattern that becomes each pixel of RGB and a colored pattern that becomes a black matrix formed at the boundary of each pixel using the above-described method for manufacturing a colored pattern, a protective film is formed on the colored pattern (each pixel of RGB and the black matrix).

[0146] The manufacturing method of the protective film is not particularly limited, and it may be formed using the photosensitive resin composition of one embodiment, or may be formed using known materials and known methods.

[0147] Through the above steps, a color filter is obtained.

[0148] Here, a case where a photosensitive resin composition containing a photopolymerization initiator (C) is used and a colored pattern is manufactured using a method of photocuring the photosensitive resin composition has been described as an example. However, for example, instead of the photopolymerization initiator (C) contained in the photosensitive resin composition, a photosensitive resin composition containing a curing accelerator and a known epoxy resin is used, and after coating on a substrate by an inkjet method, a colored pattern composed of a cured product of the photosensitive resin composition containing an alkali-soluble resin (A) may be formed using a heating method.

[0149] (Image display element) The image display element according to one embodiment of the present invention includes a color filter. In the image display element, as a configuration other than the color filter, known ones can be adopted. Specific examples of the image display element include, for example, a liquid crystal display element, an organic EL display element, a solid-state imaging device such as a CCD element and a CMOS element, and the like.

[0150] The configuration other than the color filter in the image display element can be manufactured by a known method. For example, when manufacturing a liquid crystal display element as the image display element, it can be manufactured using the method shown below. First, a color filter is formed on a substrate using the method described above. Then, electrodes, spacers, etc. are sequentially formed on the substrate having the color filter. Next, electrodes etc. are formed on another substrate, and it is bonded in a facing arrangement with the substrate having the color filter. Then, a predetermined amount of liquid crystal is injected between the opposing substrates and sealed.

[0151] Since the image display element includes a color filter having excellent solvent resistance, there is little color change.

Examples

[0152] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0153] Synthesis examples of the alkali-soluble resin (A) are shown below.

[0154] [Synthesis Example of Raw Materials] Into a flask equipped with a stirring device, a condenser, a thermometer, a cooler, and a gas inlet tube, 462.0 g of glycidyl methacrylate, 538.0 g of 2-mercaptobenzothiazole (2-MBT), and 1.0 g of 4-methoxyphenol (MEHQ) were charged, and the reaction was carried out at a reaction temperature of 80 °C for 5 hours under an air atmosphere to produce 2-hydroxy-3-(2-benzothiazolylthio)propyl methacrylate (GMA-2MBT) as the monomer (ma-1) according to this embodiment.

[0155] [Chemical Formula]

[0156] [Synthesis Example 1] Into a flask equipped with a stirring device, a condenser, a thermometer, a cooler, and a gas inlet tube, 340.5 g of propylene glycol monomethyl ether acetate, 195.9 g of Epiclon N-660 (manufactured by DIC Corporation) as an epoxy resin (100 mol as the total number of moles of epoxy groups), 144.6 g of 2-mercaptobenzothiazole as the compound represented by the above formula (2) (95 mol with respect to 100 mol of the total number of moles of epoxy groups of the epoxy resin), and 1.0 g of triphenylphosphine as a catalyst were charged, and the reaction was carried out at 120 °C for 5 hours under an air atmosphere. Next, 59.5 g of 1,2,3,6-tetrahydrophthalic anhydride as a polybasic acid anhydride (43 mol with respect to 100 mol of the total number of moles of epoxy groups of the epoxy resin) and 59.5 g of propylene glycol monomethyl ether acetate were added, and the reaction was continued at 115 °C for 2 hours to introduce a carboxy group into the side chain. Next, 200.0 g of propylene glycol monomethyl ether acetate was added to the reaction solution so that the solid content became 40.0%, and Sample No. P1 was obtained as a solution of an alkali-soluble resin (A-4). Table 1 shows the blending ratio of each raw material when converted to 100 mol of the total number of moles of epoxy groups of the epoxy resin, the weight average molecular weight, the molecular weight distribution, the equivalent number of the group represented by the formula (1), the acid value, and the refractive index of the alkali-soluble resin (A-4).

[0157] [Synthesis Example 2] Into a flask equipped with a stirring device, a condenser, a thermometer, a cooler and a gas introduction tube, 340.5 g of propylene glycol monomethyl ether acetate, 207.1 g of Epiclon N-660 (manufactured by DIC Corporation) as an epoxy resin (100 mol as the total number of moles of epoxy groups), 112.6 g of 2-mercaptobenzothiazole as the compound represented by the above formula (2) (70 mol with respect to 100 mol of the total number of moles of epoxy groups of the epoxy resin), and 1.0 g of triphenylphosphine as a catalyst were charged, and the reaction was carried out at 120 °C for 5 hours in an air atmosphere. Next, 17.3 g of acrylic acid (25 mol with respect to 100 mol of the total number of moles of epoxy groups of the epoxy resin) and 1.0 g of 4-methoxyphenol (MEHQ) were added to the above solution, and the reaction was continued at 120 °C for a certain period of time. When the acid value became 1 mg KOH / g or less, Next, 63.0 g of 1,2,3,6-tetrahydrophthalic anhydride (43 mol with respect to 100 mol of the total number of moles of epoxy groups of the epoxy resin) as a polybasic acid anhydride, 59.5 g of propylene glycol monomethyl ether acetate, and 80.3 g of propylene glycol monomethyl ether acetate (PGMEA) were added, and the reaction was continued at 115 °C for 2 hours to introduce a carboxy group into the side chain. Next, 200.0 g of propylene glycol monomethyl ether acetate was added to the reaction solution so that the solid content became 40.0%, and Sample No. P2 was obtained as a solution of an alkali-soluble resin (A-4). Table 1 shows the blending ratio of each raw material when converted to 100 mol of the total number of moles of epoxy groups of the epoxy resin, the weight average molecular weight, the molecular weight distribution, the equivalent number of the group represented by the formula (1), the acid value, and the refractive index of the alkali-soluble resin (A-4).

[0158] [Synthesis Example 3] Into a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer and a gas inlet tube, 575.3 g of propylene glycol monomethyl ether was placed. Then, it was stirred while purging with nitrogen gas and heated to 120 °C. Next, a monomer mixture consisting of 31.1 g (20 mol%) of acrylic acid as monomer (ma-2) and 245.5 g (80 mol%) of glycidyl methacrylate as monomer (ma-3), to which 33.2 g of t-butyl peroxy-2-ethylhexanoate (12 parts by mass with respect to 100 parts by mass in total of monomers (ma-2) and (ma-3)) was added as a polymerization initiator, was dropped into the flask from the dropping funnel over 1 hour. After completion of the dropping, it was stirred at 78 °C for 4 hours to carry out a copolymerization reaction, and a copolymer (P) was obtained. Next, after replacing the inside of the flask with dry air, 90.2 g (25 mol with respect to 100 mol in total of monomers (ma-2) and (ma-3)) of 2-mercaptobenzothiazole as the compound represented by the above formula (2) was added, and an addition reaction to the copolymer (P) was carried out by stirring at 60 °C for 3 hours. Then, 24.50 g of propylene glycol monomethyl ether was added as a solvent so that the solid content became 40.0%, and Sample No. P3 was obtained as a solution of the alkali-soluble resin (A-3). Table 1 shows the blending ratios of the respective monomers when converted so that the total of monomers (ma-2) and (ma-3) is 100 mol%, the weight average molecular weight, the molecular weight distribution, the equivalent number of the group represented by formula (1), the acid value, and the refractive index of the alkali-soluble resin (A-3).

[0159] [Synthesis Example 4, Synthesis Example 5] Samples No. P4 and No. P5 were obtained as solutions of the alkali-soluble resin (A-3) in the same manner as in Synthesis Example 3, except that 40 mol and 60 mol of 2-mercaptobenzothiazole were added as the compound represented by the above formula (2) with respect to 100 mol in total of monomers (ma-2) and (ma-3), respectively. Also, the evaluation was carried out in the same manner as in Synthesis Example 3, and the results are shown in Table 2.

[0160] [Synthesis Example 6] Into a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer, and a gas introduction tube, 507.9 g of propylene glycol monomethyl ether acetate was placed. Then, while stirring and replacing with nitrogen gas, the temperature was raised to 120°C. Next, 233.4 g (60%) of (GMA-2MBT) synthesized in the above raw material synthesis example as monomer (ma-1), 53.4 g (20 mol%) of 1-naphthalenemethyl acrylate as monomer (ma-4), and 35.7 g (20 mol%) of glycidyl methacrylate as monomer (ma-3) were added to a monomer mixture. To this monomer mixture, 16.1 g of t-butyl peroxy-2-ethylhexanoate (10 parts by mass based on 100 parts by mass in total of monomers (ma-4), (ma-3), and (ma-2)) as a polymerization initiator was added, and the resulting mixture was dropped from the dropping funnel into the above flask. After completion of the dropping, the mixture was stirred at 120°C for 2 hours to carry out a copolymerization reaction, and a copolymer (P) was obtained. Next, after replacing the inside of the flask with dry air, 13.6 g of acrylic acid (15 mol based on 100 mol in total of monomers (ma-4), (ma-3), and (ma-2)), 1.0 g of triphenylphosphine as a catalyst (0.3 part by mass based on 100 parts by mass in total of monomers (ma-4), (ma-3), (ma-2), and acrylic acid), and 1.0 g of hydroquinone monomethyl ether as a polymerization inhibitor (0.3 part by mass based on 100 parts by mass in total of monomers (ma-4), (ma-3), (ma-2), and acrylic acid) were added, and an addition reaction to the copolymer (P) was carried out by stirring at 120°C for 5 hours. Next, 47.8 g of 1,2,3,6-tetrahydrophthalic anhydride as a polybasic acid anhydride (25 mol based on 100 mol in total of monomers (ma-4), (ma-3), and (ma-2)) was added, and an addition reaction to the copolymer (P) was carried out by stirring at 120°C for 1 hour. Then, propylene glycol monomethyl ether was added as a solvent so that the solid content became 40.0%, and Sample No. P6 was obtained as a solution of an alkali-soluble resin (A-3). Table 1 shows the blending ratios of the respective monomers when converted so that the total of monomers (ma-2), (ma-3), and (ma-4) is 100 mol%, the weight average molecular weight, the molecular weight distribution, the equivalent number of the group represented by formula (1), the acid value, and the refractive index of the alkali-soluble resin (A-2).

[0161] [Synthesis Example 7] To a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer, and a gas introduction tube, 454.6 g of propylene glycol 1-monomethyl ether (PGME) was added, and the mixture was stirred while purging with nitrogen and heated to 78°C. Next, a monomer mixture consisting of 330.6 g (70 mol%) of (GMA-2MBT) synthesized in the above raw material synthesis example as monomer (ma-1) and 33.0 g (30 mol%) of acrylic acid as monomer (ma-2), 36.4 g of 2,2'-azobis(2-methylpropionic acid) dimethyl (polymerization initiator, manufactured by NOF Corporation, V-601) as a polymerization initiator, and 145.4 g of propylene glycol 1-monomethyl ether (PGME) were added, and the resulting mixture was dropped into the above flask from the dropping funnel over 1 hour. After completion of the dropping, the mixture was further stirred at 98°C for 4 hours to carry out a copolymerization reaction. Then, propylene glycol monomethyl ether was added as a solvent so that the solid content became 40.0%, and Sample No. P7 was obtained as a solution of an alkali-soluble resin (A-1). Table 1 shows the blending ratio of each monomer when the total of monomers (ma-1) and (ma-2) is converted to 100 mol%, the weight average molecular weight, molecular weight distribution, equivalent number of the group represented by formula (1), acid value, and refractive index of the alkali-soluble resin (A-1).

[0162] [Synthesis Example 8] To a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer, and a gas introduction tube, 413.4 g of propylene glycol monomethyl ether acetate (PGMEA) was added, and the mixture was stirred while purging with nitrogen and heated to 78°C. Next, 233.4 g (60 mol%) of (GMA-2MBT) synthesized in the above raw material synthesis example as monomer (ma-1), 20.0 g (20 mol%) of acrylic acid as monomer (ma-2), and a monomer mixture composed of 4-hydroxyphenyl methacrylate as monomer (ma-4) were added with 33.1 g of 2,2'-azobis(2-methylpropionic acid) dimethyl (polymerization initiator, manufactured by NOF Corporation, V-601) as a polymerization initiator and 132.3 g of propylene glycol 1-methyl ether (PGME), and the resulting mixture was dropped into the above flask from a dropping funnel over 1 hour. After completion of the dropping, the mixture was further stirred at 98 °C for 4 hours to conduct a copolymerization reaction. Thereafter, propylene glycol monomethyl ether was added as a solvent so that the solid content became 40.0%, and Sample No. P8 was obtained as a solution of the alkali-soluble resin (A-1). Table 1 shows the blending ratio of each monomer when the total of monomer (ma-1) and (ma-2) is converted to 100 mol%, the weight-average molecular weight, molecular weight distribution, equivalent number of the group represented by formula (1), acid value, and refractive index of the alkali-soluble resin (A-1).

[0163] [Comparative Synthesis Example 1] (GMA-2MBT) was synthesized in the same manner as in the above raw material synthesis example. Next, propylene glycol monomethyl ether acetate was added to the reaction solution so that the solid content became 40.0%, and Sample No. cP1 was obtained as a solution of Comparative Synthesis Example 1. Table 1 shows the molecular weight, equivalent number of the group represented by formula (1), acid value, and refractive index of Sample No. cP1 of Comparative Synthesis Example 1.

[0164] [Comparative Synthesis Example 2] Into a flask equipped with a stirring device, a condenser, a thermometer, a cooler, and a gas introduction tube, 400.0 g of propylene glycol monomethyl ether acetate, 230.2 g of Epiclon N-660 (manufactured by DIC Corporation) as an epoxy resin (100 moles as the total number of moles of epoxy groups), 169.8 g of 2-mercaptobenzothiazole as the compound represented by the above formula (2) (95 moles relative to 100 moles of the total number of moles of epoxy groups of the epoxy resin), and 1.2 g of triphenylphosphine as a catalyst were charged, and the reaction was carried out at 120 °C for 5 hours in an air atmosphere. Next, 200 g of propylene glycol monomethyl ether acetate was added to the reaction solution so that the solid content became 40.0%, and sample No. cP2 was obtained as the resin solution of Comparative Synthesis Example 2. Table 1 shows the blending ratios of each raw material when converted to 100 moles of the total number of moles of epoxy groups of the epoxy resin, and the weight average molecular weight, molecular weight distribution, equivalent number of the group represented by formula (1), acid value, and refractive index of the resin of Comparative Synthesis Example 2.

[0165] [Comparative Synthesis Example 3] 454.6 g of propylene glycol 1-monomethyl ether (PGME) was added to a flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer, and a gas introduction tube, and the mixture was stirred while purging with nitrogen and heated to 78 °C. Next, a monomer mixture consisting of 354.5 g (90 mol%) of GMA-2MBT as monomer (ma-1) and 9.2 g (10 mol%) of acrylic acid as monomer (ma-2), 36.3 g of 2,2'-azobis(2-methylpropionic acid) dimethyl (polymerization initiator, manufactured by NOF Corporation, V-601) as a polymerization initiator, and 145.5 g of propylene glycol 1-monomethyl ether (PGME) were added, and the resulting mixture was dropped into the flask from the dropping funnel over 1 hour. After the dropping was completed, the mixture was further stirred at 98 °C for 4 hours to carry out a copolymerization reaction, and sample No. cP3 was obtained as the resin solution of Comparative Synthesis Example 3. Table 1 shows the blending ratios of each monomer when converted so that the total of monomers (ma-1) and (ma-2) is 100 mol%, and the weight average molecular weight, molecular weight distribution, equivalent number of the group represented by formula (1), acid value, and refractive index of the resin of Comparative Synthesis Example 3.

[0166]

Table 1

[0167] In Table 1, the meanings of the respective symbols are as follows. GMA: Glycidyl methacrylate GMA-2MBT: 2-Hydroxy-3-(2-benzothiazolylthio)propyl methacrylate Epiclon N-660: Epoxy resin AA: Acrylic acid MAA: Methacrylic acid PQMA: 4-Hydroxyphenyl methacrylate NMT-A: 1-Naphthalenemethyl acrylate 2MBT: 2-Mercaptobenzothiazole THPA: 1,2,3,6-Tetrahydrophthalic anhydride SA: Succinic anhydride PGMEA: Propylene glycol monomethyl ether acetate PGME: Propylene glycol monomethyl ether

[0168]

Table 2

[0169] Preparation examples of the photosensitive resin composition are shown below. (Examples 1 to 8, Comparative Examples 1 to 3) As the resin (A), the samples P1 to P8, cP1 to cP3 obtained in Synthesis Examples 1 to 8 and Comparative Synthesis Examples 1 to 3, and the components (B), (C), and (D) shown in Table 3 were mixed at the ratios shown in Table 3, and the photosensitive resin compositions R1 to R8 and cR1 to cR3 of Examples 1 to 8 and Comparative Examples 1 to 3 were respectively prepared.

[0170] Note that the blending amount of resin (A) in the photosensitive resin composition in Table 3 does not include the solvent used in the synthesis of resin (A). Also, the blending amount of solvent (D) in Table 3 is the total amount of the solvent used in the synthesis of resin (A) in the photosensitive resin composition and the solvent additionally added during the preparation of the photosensitive resin composition.

[0171]

Table 3

[0172] (Evaluation of Photosensitive Resin Composition) The photosensitive resin compositions R1 to R8 and cR1 to cR3 prepared in Examples 1 to 8 and Comparative Examples 1 to 3 were evaluated by the methods shown below. The results are shown in Tables 4 and 5.

[0173] (Method for Measuring Refractive Index) The refractive index means the refractive index of copolymer (A) measured using a refractometer. The refractive index of the resin composition (sample) containing copolymer (A) and solvent (D) of the present invention was measured under the following conditions, and then the refractive index of solvent (D) was measured under the following conditions. Next, the content (solid content) of copolymer (A) contained in the sample was measured according to JIS K6901 5.11, and the refractive index of copolymer (A) alone contained in the sample was calculated using the following formula. Measuring instrument: J-357 Automatic Refractometer (Rudolph Research Analytical) Measurement wavelength: 589 nm Measurement temperature: 25 °C Refractive index of copolymer (A) alone = (Refractive index of sample - Refractive index of solvent (D)) ÷ Solid content × 100 + Refractive index of solvent (D)

[0174] (Method for Measuring Solid Content) The heating residue when the sample obtained in the following synthesis example was heated at 130 °C for 2 hours was measured.

[0175] (Evaluation of Stability) The viscosity was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at a liquid temperature of 25°C, a rotation speed of 10 rpm, and a rotor of 1°34’×R24. Each test sample of 10 g was weighed into a 20-ml glass container, sealed, and subjected to a storage test in which it was left standing in a thermostat maintained at 12°C for 3 months. For each test sample after the storage test, the weight-average molecular weight (Mw) and the viscosity at 25°C were measured again by the above method. Using the weight-average molecular weight (Mw) before and after the storage test, and the viscosity at 25°C before and after the storage test, the increase rate of the weight-average molecular weight and the increase rate of the viscosity at 25°C were determined by the following formulas (I) and (II), respectively, and evaluated according to the criteria shown below. The results are shown in Tables 4 and 5.

[0176] Increase rate of weight-average molecular weight (%) = ((Weight-average molecular weight before storage test - Weight-average molecular weight after storage test) / Weight-average molecular weight before storage test) × 100 (I)

[0177] Increase rate of viscosity (%) = ((Viscosity before storage test - Viscosity after storage test) / Viscosity before storage test) × 100 (II)

[0178] The stability was evaluated according to the following criteria. The results are shown in Table 4 or Table 5.

[0179] Evaluation criteria: ◎: Both the increase rate of the molecular weight and the increase rate of the viscosity are less than 5%. ○: Both the increase rate of the molecular weight and the increase rate of the viscosity are less than 10%. △: One or both of the increase rate of the molecular weight and the increase rate of the viscosity are 10% or more and less than 20%.

[0180] Pattern formation by the photosensitive resin composition (without development) Each photosensitive resin composition was spin-coated on a 5 cm square glass substrate (non-alkali glass substrate) so that the average thickness of the final cured coating film was 2.0 μm, and then heated at 100 °C for 3 minutes to volatilize the solvent. Next, the entire surface of the coating film was exposed (exposure amount: 200 mJ / cm2) and photocured, and then baked at 230 °C for 30 minutes to obtain a resist which is a resin cured film.

[0181] <Evaluation of transmittance> Measurement was performed using a spectrophotometer UV-1650PC (manufactured by Shimadzu Corporation).

[0182] Evaluation criteria: ○: 98% or more. ×: Less than 98%.

[0183] <Evaluation of fine line adhesion and residue> The photosensitive resin compositions of Examples 1 to 9 and Comparative Examples 1 to 3 were each applied onto a 5 cm square glass substrate (non-alkali glass substrate) by the spin coating method so that the thickness after exposure was 2.5 μm (coating step). The glass substrate coated with the photosensitive resin composition was heated at 100 °C for 3 minutes to volatilize the solvent and dry the coating film (pre-baking step). Next, light of 200 mJ / cm2 was irradiated onto the surface of the dried coating film through a photomask using an ultra-high pressure mercury lamp (exposure step). The exposure step was performed with the photomask placed at a position 100 μm away from the coating film. As the photomask, one having a line and space pattern with a width of 3 to 100 μm was used. Next, it was immersed in a 2.38% aqueous solution of tetramethylammonium hydroxide at a temperature of 23 °C for 10 s to 180 s for development to remove the unexposed portion (development step). The glass substrate having the coating film after the development step was allowed to stand in a dryer at 100 °C for 30 minutes to thermally cure the coating film (post-baking step) to obtain a pattern. The pattern obtained in this way was observed using an electron microscope S-3400 manufactured by Hitachi High-Technologies Corporation, and the minimum line width (minimum development dimension) that could be developed and the presence or absence of residue in the unexposed portion between the developed patterns were evaluated. The presence or absence of residue was evaluated according to the following criteria. The results are shown in Table 4 or Table 5.

[0184] Evaluation criteria: ○: No residue in the unexposed portion between the developed patterns. ×: There is residue in the unexposed portion between the developed patterns.

[0185] <Overall judgment> For the photosensitive resin compositions and the resin cured films composed of the cured products thereof of Examples 1 to 9 and Comparative Examples 1 to 3, evaluation was carried out according to the following criteria. The results are shown in Table 4 or Table 5.

[0186] Evaluation criteria: ○: All of the following items are satisfied. (1) The refractive index of the resin (589 nm) is 1.55 or more. (2) Both the increase rate of the molecular weight of the resin and the increase rate of the viscosity are less than 10%. (3) The transmittance is 98% or more. (4) The minimum development dimension in developability is 30 μm or less, and there is no residue in the unexposed portion. ×: Does not satisfy any one or more of the items of ○ above, and there is one ×.

[0187]

Table 4

[0188]

Table 5

[0189] (Discussion) From the results of Tables 4 and 5, in Examples 1 to 8 using the alkali-soluble resin (A) obtained in Synthesis Examples 1 to 8, resin cured films having high refractive indices and transmittances were obtained, and photosensitive resin compositions with good stability could be prepared. Also, compared with Comparative Examples 1 to 3 using the alkali-soluble resins obtained in Comparative Synthesis Examples 1 to 3, photosensitive resin compositions with good developability could be prepared.

[0190] In Examples 1 to 2, the alkali-soluble resin (A4) according to this embodiment was used. The refractive index of the main chain is high, and the birefringence may be close to 0. In Examples 3 to 5, the alkali-soluble resin (A3) according to this embodiment was used. Epoxy groups remain in the resin and heat-curing performance is imparted. It is easy to synthesize. It can also be copolymerized with a third component. In Example 6, the alkali-soluble resin (A2) according to this embodiment was used. Since it can be copolymerized using GMA-2MBT as a high refractive index monomer and directly introduced into the resin, it is easy to use without generating unreacted 2MBT. Also, since double bonds can be introduced, the compatibility with a reactive diluent (B) such as dipentaerythritol hexa(meth)acrylate is improved, and the developability is improved. In Examples 7 to 8, the alkali-soluble resin (A1) according to this embodiment was used. Since it can be copolymerized using GMA-2MBT as a high refractive index monomer and directly introduced into the resin, it is easy to use without generating unreacted 2MBT. Also, carboxyl groups are introduced by copolymerizing acrylic acid, and since an addition reaction is not required, synthesis is easy. Unreacted low molecular components are also less likely to occur, and the development residue can be significantly reduced.

[0191] In Comparative Examples 1 and 2, even though they have the group represented by the above formula (1), since the solid content acid value is 0.0 KOH mg / g, the developability is poor and the overall judgment is ×. In Comparative Example 3, even though it has the group represented by the above formula (1), since the solid content acid value is as low as less than 20 KOH mg / g, the developability is poor and the overall judgment is ×.

Claims

1. having a group represented by the following formula (1), an alkali-soluble resin, characterized in that the acid value is 20 to 300 mg KOH / g. 【Chemical 1】 (wherein, R １ and R ２ are each independently -O-, -S-, or -N(R ５ ), R ４ is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R ５ is H, an alkyl group, or an alkoxy group, and p is an integer of 0 to 4).

2. The alkali-soluble resin according to claim 1, wherein the equivalent number of the group represented by the above formula (1) is 200 to 1100 g / mol.

3. The alkali-soluble resin according to claim 1, wherein the refractive index is 1.40 or more.

4. The alkali-soluble resin according to claim 1, wherein the weight average molecular weight is 1000 to 50000.

5. The alkali-soluble resin is a copolymer containing a structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) and a structural unit (a-2) derived from an ethylenically unsaturated compound (ma-2) having an acid group, the alkali-soluble resin according to claim 1.

6. Based on 100 mol% of all structural units, the structural unit (a-1) is 10 to 95 mol%, the structural unit (a-2) is 5 to 90 mol%, the alkali-soluble resin according to claim 5.

7. The alkali-soluble resin is a first-modified copolymer in which a compound having a group reactive with an epoxy group and an ethylenically unsaturated group is further added to a part of the epoxy groups of a copolymer containing a structural unit (a-1) derived from an ethylenically unsaturated compound (ma-1) having a group represented by the above formula (1) and a structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group, and a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by ring-opening of the epoxy groups, the alkali-soluble resin according to claim 1.

8. Based on 100 mol% of the total of the structural units constituting the first-modified copolymer, the structural unit (a-1) is 10 to 95 mol%, the structural unit (a-3) is 5 to 90 mol%, the addition rate of the compound having a group reactive with an epoxy group and an ethylenically unsaturated group with respect to the number of moles of the epoxy groups derived from the structural unit (a-3) is 10 to 90 mol%, the alkali-soluble resin according to claim 7.

9. The alkali-soluble resin is a second modified copolymer in which a compound represented by the following formula (2) is added to a part of the epoxy groups of a copolymer containing a structural unit (a-2) derived from an ethylenically unsaturated compound (ma-2) having an acid group and a structural unit (a-3) derived from an ethylenically unsaturated compound (ma-3) having an epoxy group. The alkali-soluble resin according to claim 1. 【Chemical 2】 (wherein, R ２ is -O-, -S-, or -N(R ５ ), R ４ is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R １２ is -OH, -SH, or -NHR ５ and R ５ is H, an alkyl group, or an alkoxy group, and p is an integer of 0 to 4.)

10. With respect to a total of 100 mol% of the structural units constituting the second modified copolymer, the structural unit (a-2) is 5 to 90 mol%, the structural unit (a-3) is 10 to 95 mol%, The addition rate of the compound represented by the above formula (2) with respect to the number of moles of the epoxy group derived from the structural unit (a-3) is 10 to 90 mol%. The alkali-soluble resin according to claim 9.

11. The alkali-soluble resin is a third modified copolymer in which a polybasic acid or its anhydride is further added to a part of the hydroxy groups generated by the ring-opening of the epoxy groups of the second modified copolymer. The alkali-soluble resin according to claim 9.

12. The alkali-soluble resin is a modified epoxy resin in which a compound represented by the following formula (2) is added to a part of the epoxy groups of the epoxy resin, and a polybasic acid or its anhydride is added to a part of the hydroxy groups generated by the ring-opening of the epoxy groups. The alkali-soluble resin according to claim 1. [Chemical Formula 3] (wherein, R ２ is -O-, -S-, or -N(R ５ ), R ４ is a halogen group, an alkyl group, an alkoxy group, or an aromatic group, R １２ is -OH, -SH, or -NHR ５ ), R ５ is H, an alkyl group, or an alkoxy group, and p is an integer of 0 to 4. )

13. The addition rate of the compound represented by the above formula (2) with respect to the number of moles of the epoxy group of the epoxy resin is 10 to 90 mol%. The alkali-soluble resin according to claim 12.

14. An alkali-soluble resin (A), a reactive diluent (B), a photopolymerization initiator (C), a solvent (D), A photosensitive resin composition containing The alkali-soluble resin (A) is the alkali-soluble resin according to any one of claims 1 to 13. A photosensitive resin composition.

15. With respect to a total of 100% by mass of the alkali-soluble resin (A) and the reactive diluent (B), the alkali-soluble resin (A) is 10 to 99% by mass, the reactive diluent (B) is 1 to 90% by mass, With respect to a total of 100 parts by mass of the alkali-soluble resin (A) and the reactive diluent (B), the photopolymerization initiator (C) is 0.1 to 30 parts by mass, With respect to a total of 100 parts by mass of the components excluding the solvent (D), the solvent (D) is 30 to 1000 parts by mass. The photosensitive resin composition according to claim 14.

16. A resin cured film comprising a cured product of the photosensitive resin composition according to claim 14.

17. An image display element comprising the resin cured film according to claim 16.

Images