Alkali-soluble resin composition and cured product thereof

Abstract

To provide an alkali-soluble resin composition capable of giving a cured product having a high refractive index, and to provide a cured product thereof.SOLUTION: The alkali-soluble resin composition contains an alkali-soluble resin having a structure represented by the following formula (1) and metal oxide particles. (In the formula (1), R1 and R8 are the same or different and each represent a monovalent organic group having a polymerizable double bond; at least one of R2 and R7 represents a group represented by the following formula (2); and X represents a direct bond or a divalent organic group.) (In the formula (2), R9 represents an optionally substituted divalent organic group.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an alkali-soluble resin composition and a cured product thereof. More specifically, this invention relates to an alkali-soluble resin composition that can yield a cured product with a high refractive index, and a cured product thereof. [Background technology]

[0002] Alkali-soluble resin compositions have been explored for various applications in optical components and electrical / electronic equipment, such as color filters used in liquid crystal displays and solid-state image sensors, inks, printing plates, printed circuit boards, semiconductor elements, photoresists, organic insulating films, and organic protective films. Resins and resin compositions with superior properties required for each application have been developed.

[0003] In recent years, there has been a growing trend towards miniaturization, thinning, and energy efficiency in optical components, electrical and electronic equipment, and consequently, higher performance is required for the various components used. To meet these demands, research is being conducted on alkali-soluble resin compositions that serve as materials for various components.

[0004] To date, alkali-soluble resin compositions have been developed to meet a variety of requirements. For example, Patent Document 1 describes a photosensitive resin composition for image formation that can achieve both alkali developability and photocurability, and further provides a cured product that is excellent in dimensional stability with respect to temperature changes and does not exhibit brittleness. This composition contains an acid-modified vinyl ester obtained by synthesizing an epoxy compound, a phenol compound, an unsaturated monobasic acid, and a polybasic acid anhydride, using a crystalline epoxy resin with a melting point of 90°C or higher as at least a portion of the epoxy compound, and a phenol compound having a bisphenol S skeleton as at least a portion of the phenol compound.

[0005] For example, Patent Document 2 describes a photosensitive resin composition that, even as a thin film, has a high dielectric constant and can suppress leakage current while enabling the formation of high-resolution patterns by photolithography. This photosensitive resin composition contains zirconium dioxide particles, a dispersant, a solvent, a binder resin, a polymerizable monomer, and a polymerization initiator, wherein the binder resin contains at least one of an epoxy (meth)acrylate resin having a specific repeating unit structure and an epoxy (meth)acrylate resin having a specific substructure. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-250306 [Patent Document 2] International Publication No. 2018 / 021497 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, these conventional alkali-soluble resin compositions have low refractive indices, and while a high refractive index of 1.60 or higher is required for optical applications where such a high refractive index is necessary, such requirements have not yet been adequately met.

[0008] This invention has been made in view of the above-mentioned circumstances, and aims to provide an alkali-soluble resin composition that can yield a cured product with a high refractive index, and a cured product thereof. [Means for solving the problem]

[0009] The inventors of the present invention conducted various studies on alkali-soluble resins and discovered that by including an alkali-soluble resin having a specific structure and metal oxide particles, it is possible to obtain a resin composition that can yield a cured product with a high refractive index of 1.60 or higher, thus completing the present invention.

[0010] That is, the present invention provides an invention of the following aspect. [1] An alkali-soluble resin composition comprising an alkali-soluble resin having a structure represented by the following formula (1) and metal oxide particles.

[0011] [Chemical formula]

[0012] (In formula (1), R 1 and R 8 each independently represent a monovalent organic group having a polymerizable double bond. R 2 and R 7 each independently represent a hydrogen atom or a group represented by the following formula (2), and at least one of R 2 and R 7 is a group represented by the following formula (2). R 3 and R 6 each independently represent a divalent organic group. R 4 and R 5 each independently represent a substituent. X represents a direct bond or a divalent organic group. a represents the number of R 4 and is an integer from 0 to 4. When there are a plurality of R 4 , they may be the same or different from each other. b represents the number of R 5 and is an integer from 0 to 4. When there are a plurality of R 5 , they may be the same or different from each other. n represents an integer of 1 or more. When n is an integer of 2 or more, a plurality of R 4 , R 5 , R 6 , R 7 and X may be the same as or different from each other. )

[0013] [Chemical formula] (In formula (2), R 9 represents a divalent organic group which may have a substituent. )

[0014] [2] The alkali-soluble resin composition according to [1] above, characterized in that the metal oxide particles include at least one metal element selected from the group consisting of titanium, aluminum, zirconium, zinc, tin, cerium, and silicon. [3] The alkali-soluble resin composition according to [1] or [2] above, characterized in that the metal oxide particles are surface-modified metal oxide particles. [4] The alkali-soluble resin composition according to any one of [1] to [3] above, further characterized by containing epoxy (meth)acrylate. [5] The alkali-soluble resin composition according to any one of [1] to [4] above, further comprising a polymerizable compound and a photopolymerization initiator. [6] An alkali-soluble resin composition according to any one of [1] to [5] above, characterized in that it is for forming a high refractive index transparent film. [7] A cured product obtained by curing any of the alkali-soluble resin compositions described in [1] to [6] above. [Effects of the Invention]

[0015] The alkali-soluble resin composition of the present invention can yield cured products with a high refractive index. The alkali-soluble resin composition of the present invention can be widely applied to various applications such as optical components, electrical and electronic components, and display devices. [Modes for carrying out the invention]

[0016] The present invention will be described in detail below. Furthermore, combinations of two or more of the individual preferred embodiments of the present invention described below are also preferred embodiments of the present invention. Furthermore, in this specification, "(meth)acrylate" means "acrylate and / or methacrylate," and "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid."

[0017] 1. Alkali-soluble resin composition The alkali-soluble resin composition of the present invention is characterized by comprising an alkali-soluble resin having a structure represented by the following formula (1) and metal oxide particles.

[0018] [ka]

[0019] (In formula (1), R 1 and R 8 R represents a monovalent organic group having a polymerizable double bond, either identical or different. 2 and R 7 R represents a hydrogen atom or a group represented by the following formula (2), either identical or different. 2 and R 7 At least one of them is a group represented by the following formula (2). R 3 and R 6 R represents a divalent organic group, which may be the same or different. 4 and R 5 represents a substituent, either identical or different. X represents a directly bonded or divalent organic group. a represents R 4 This represents the number of elements, and is an integer from 0 to 4, R 4 If there are multiple instances, they may be the same or different. b is R 5 This represents the number of elements, and is an integer from 0 to 4, R 5 If there are multiple R's, they may be the same or different. n represents an integer of 1 or greater. If n is an integer of 2 or greater, there are multiple R's. 4 , R 5 , R 6 , R 7 X and X may be the same or different.

[0020] [ka] (In formula (2), R 9 (This represents a divalent organic group that may have substituents.)

[0021] The alkali-soluble resin composition of the present invention can yield a cured product with a high refractive index because the alkali-soluble resin has a specific structure containing an aromatic ring, which enables it to exhibit a high refractive index. Furthermore, this structure results in high hydrophobicity and good compatibility with metal oxide particles, allowing the metal oxide particles to disperse well in the resin and fully exert their functions.

[0022] The components contained in the alkali-soluble resin composition of the present invention are described below. (1) Alkali-soluble resin The alkali-soluble resin used in the present invention has a structure represented by the above formula (1). In the above equation (1), R 1 and R 8 This represents a monovalent organic group having a polymerizable double bond, whether identical or different. Having a monovalent organic group with a polymerizable double bond allows for the formation of a resin with excellent photocurability.

[0023] Examples of polymerizable double bonds include (meth)acryloyl groups, vinyl groups, allyl groups, and methallyl groups. Among these, (meth)acryloyl groups are preferred.

[0024] Examples of the monovalent organic group include a monovalent hydrocarbon group which may have substituents, or a group which is a combination of the monovalent hydrocarbon group which may have substituents and -O-, -CO-, -COO-, -NH-, -S-, -SO-, or -SO2-.

[0025] Examples of the monovalent hydrocarbon group mentioned above include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, or aromatic hydrocarbon groups. Among these, aliphatic hydrocarbon groups or alicyclic hydrocarbon groups are preferred.

[0026] Examples of monovalent aliphatic hydrocarbon groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, sec-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, 2-methylpentyl group, 3-methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, heptyl group, 2-methylhexyl group, 3-methylhexyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3-ethylpentyl group, 2,2,3-trimethylbutyl group, octyl group, methylheptyl group, dimethylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, trimethylpentyl group, 3-ethyl-2-methylpentyl group, 2-ethyl-3-methylpentyl group, and 2,2,3,3-teto Methylbutyl group, nonyl group, methyloctyl group, 3,7-dimethyloctyl group, dimethylheptyl group, 3-ethylheptyl group, 4-ethylheptyl group, trimethylhexyl group, 3,3-diethylpentyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, etc. Alkyl groups include vinyl groups, n-propenyl groups, isopropenyl groups, 1-butenyl groups, 2-butenyl groups, 1-pentenyl groups, 2-pentenyl groups, 2-methyl-1-butenyl groups, 2-methyl-2-butenyl groups, 3-methyl-1-butenyl groups, 1-hexenyl groups, 2-hexenyl groups, 1-heptenyl groups, 2-heptenyl groups, 1-octenyl groups, or 2-octenyl groups, and other alkenyl groups.

[0027] Examples of monovalent alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecyl, adamantyl, and norbornyl; and cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and cyclohexadienyl.

[0028] Examples of monovalent aromatic hydrocarbon groups include phenyl, naphthyl, biphenylel, methoxyphenyl, trichlorophenyl, ethylphenyl, tolyl, xylyl, and benzyl groups.

[0029] Examples of the substituents mentioned above include carboxyl groups, hydroxyl groups, amino groups, halogen atoms, or groups consisting of combinations thereof.

[0030] In particular, the monovalent organic group having the polymerizable double bond described above is preferably the group represented by the following formula (3), as it can form a cured product with a high crosslink density when the resin is cured. -R 10 -O-CO-CR 11 =CR 12 R 13 (3) (In the formula, R 10 R represents a directly bonded or divalent organic group. 11 , R 12 and R 13 (These represent, either identical or distinct, a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.)

[0031] In equation (3) above, R 10 Examples of divalent organic groups represented by include groups obtained by divalentizing the monovalent organic groups mentioned above. Specifically, examples of the above divalent organic groups include divalent hydrocarbon groups which may have substituents, -O-, -CO-, -COO-, -NH-, -S-, -SO-, -SO2-, or groups consisting of combinations thereof. Among these, groups which may have substituents, -O-, -CO-, -COO-, or groups consisting of combinations thereof are preferred in terms of good heat resistance to coloring, and groups consisting of combinations of divalent hydrocarbon groups, -O-, and -CO- are more preferred.

[0032] Examples of the above-mentioned divalent hydrocarbon groups include divalent aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, or aromatic hydrocarbon groups. Examples of divalent aliphatic hydrocarbon groups include alkylene groups such as methylene, ethylene, propylene, isopropylene, butylene, isobutylene, t-butylene, pentylene, neopentylene, hexamethylene, heptylene, octylene, 2-ethylhexylene, nonylene, decylene, undecylene, and dodecylene; and alkenylene groups such as vinylene, propenylene, isopropenylene, butenylene, butadienylene, pentenylene, hexenylene, and heptenylene.

[0033] Examples of divalent alicyclic hydrocarbon groups include cycloalkylene groups such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, norbornylene, and adamantylene; cycloalkenylene groups such as cyclopropenylene, cyclobutenylene, and cyclopentenylene; and cycloalkylidene groups such as cyclopentylidene and cyclohexylidene.

[0034] Examples of divalent aromatic hydrocarbon groups include arylene groups such as phenylene, torylene, and naphthylene, as well as cinnamyridene and biphenylene groups.

[0035] In particular, the above-mentioned divalent hydrocarbon group is preferably a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group, more preferably a divalent aliphatic hydrocarbon group, and even more preferably an alkylene group.

[0036] The number of carbon atoms in the above-mentioned divalent hydrocarbon group is preferably 1 to 7, more preferably 1 to 5, and even more preferably 1 to 3, in terms of excellent dimensional stability.

[0037] The substituents that the above-mentioned divalent hydrocarbon group may have include carboxyl groups, hydroxyl groups, alkoxy groups, halogen atoms, and hydrocarbon groups having 1 to 7 carbon atoms.

[0038] The above R 10 A preferred specific example of a divalent organic group represented by -Ra -COO-, -R a -OCO-R a -COO-, -R a -COO-R a -COO- (both R a These represent divalent organic groups, which are either the same or different. Examples include -R a -COO-(R a ) represents a divalent hydrocarbon group. ) is more preferable. The above R 10 Direct bonding is most preferable.

[0039] In equation (3) above, R 11 , R 12 and R 13 Examples of C1-C6 hydrocarbon groups represented include chain-like or cyclic hydrocarbon groups, but chain-like hydrocarbon groups with C1-C6 are preferred, and alkyl groups with C1-C6 are more preferred. In particular, due to the good reactivity of the unsaturated double bond, R 11 , R 12 and R 13 R is preferably the same or different hydrogen atom or methyl group. 12 , R 13 is a hydrogen atom, and R 11 It is more preferable that the atom is a hydrogen atom or a methyl group.

[0040] In the above equation (1), R 2 and R 7 R represents a hydrogen atom or a group represented by the following formula (2), either identical or different. 2 and R 7 At least one of them is a group represented by formula (2) above. In equation (2) above, R 9 R represents a divalent organic group which may have substituents. 9 As a divalent organic group represented by the above, R 10 Examples of similar groups to the divalent organic group represented by include . Among them, R 9The divalent organic group represented is preferably a divalent hydrocarbon group, more preferably a divalent aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, and even more preferably a divalent aliphatic hydrocarbon group or an alicyclic hydrocarbon group. The above organic group may also have a double bond.

[0041] The above R 9 The number of carbon atoms in the divalent organic group represented is preferably 1 to 20, more preferably 1 to 10, even more preferably 1 to 8, even more preferably 2 to 6, particularly preferably 2 or 6, and most preferably 6.

[0042] The above R 9 Examples of substituents that the divalent organic group represented by may have include carboxyl groups and hydrocarbon groups having 1 to 20 carbon atoms. Among these, carboxyl groups are preferred because they can improve alkali solubility.

[0043] In the above equation (1), R 3 and R 6 R represents a divalent organic group, which may be the same or different. 3 or R 6 As a divalent organic group represented by the above, R 10 Examples of groups similar to the divalent organic group represented by can be cited, but among them, divalent hydrocarbon groups which may have substituents are preferred, and divalent hydrocarbon groups are more preferred. The above R 3 and R 6 Examples of divalent hydrocarbon groups represented by include the aforementioned divalent aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, or aromatic hydrocarbon groups, but among these, divalent aliphatic hydrocarbon groups are preferred, and alkylene groups are preferred. The number of carbon atoms in the hydrocarbon group is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. Examples of substituents that the above-mentioned divalent hydrocarbon group may have include hydrocarbon groups having 1 to 10 carbon atoms, halogen atoms, cyano groups, and the like.

[0044] In the above formula (1), R 4 and R 5 each independently represent a substituent, which may be the same or different. Examples of the substituent represented by the above R 4 or R 5 include any monovalent substituent, for example, a carboxyl group, a hydroxyl group, an amino group, a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, or a group composed of a combination thereof. Even if the above substituent is an arbitrary substituent, due to the stacking interaction of the aromatic ring, the alkali-soluble resin can form a dense cured product, and a cured product with a high refractive index can be obtained.

[0045] a represents the number of substituents R 4 and is an integer from 0 to 4, preferably from 0 to 2, more preferably 0 or 2. When there are a plurality of R 4 they may be the same or different from each other. b represents the number of substituents R 5 and is an integer from 0 to 4, preferably from 0 to 2, more preferably 0 or 2. When there are a plurality of R 5 they may be the same or different from each other.

[0046] In the above formula (1), X represents a direct bond or a divalent organic group Examples of the divalent organic group represented by X include, for example, the same groups as the divalent organic groups represented by the above R 10 Among them, a divalent hydrocarbon group which may have a substituent, -SO2-, or a combination thereof is preferable, a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, or -SO2- is more preferable, a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, or -SO2- is still more preferable, a divalent saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, or -SO2- is still more preferable, and -SO2- is most preferable.

[0047] Examples of the above substituent include the above-mentioned substituents and the like, among which halogen atoms such as fluorine atoms, chlorine atoms, and iodine atoms are preferably mentioned. When the divalent hydrocarbon group has a ring structure, the substituents preferably include a halogen atom and an alkyl group.

[0048] X is preferably a direct bond, an alkylene group, or -SO2-, more preferably a direct bond, an alkylene group having 1 to 10 carbon atoms, or -SO2-, and even more preferably a direct bond or -SO2-.

[0049] In the above formula (1), n represents an integer of 1 or more. When n is an integer of 2 or more, R 4 , R 5 , R 6 , R 7 and X will be present in plural, but the plural Rs 4 , R 5 , R 6 , R 7 and X may be the same as each other or different from each other. In terms of obtaining a cured product with a higher refractive index, n is preferably an integer of 2 or more, and more preferably an integer of 3 or more. Also, in terms of good solubility in a solvent, n is preferably an integer of 5 or less, and more preferably an integer of 4 or less. n represents the average value of the number of repeating units.

[0050] As a preferred form of the alkali-soluble resin represented by the above formula (1), as the bifunctional epoxy compound of formula (4) described later, a resin obtained by using a reaction product of a bifunctional epoxy compound P' represented by formula (4') and a bisphenol compound represented by formula (5) can be mentioned. The reaction product of the bifunctional epoxy compound P' represented by formula (4') and the bisphenol compound represented by formula (5) has a structure in which two structural parts derived from the bifunctional epoxy compound P' represented by formula (4') are linked by a structural part derived from the bisphenol compound represented by formula (5). When the alkali-soluble resin represented by the above formula (1) is obtained using such a reaction product, the relationship between n in formula (1), m' in formula (4'), and q in formula (5) satisfies n = 2m' + q. Also, when the structure within [] in formula (1) is defined as structural unit α, R in the above formula (1)1 m' of the above structural units α from the lateral end, and R 8 In m' of the above structural units α from the lateral end, R 4 , R 5 , R 6 X, a, and b are all the same. Having such a structure in the alkali-soluble resin represented by formula (1) is one of the preferred embodiments of the present invention.

[0051] The acid value of the alkali-soluble resin described above is preferably 30 to 150 mg KOH / g, more preferably 40 to 135 mg KOH / g, even more preferably 50 to 120 mg KOH / g, and most preferably 70 to 100 mg KOH / g. The above acid value is obtained by a neutralization titration method using potassium hydroxide (KOH) solution and represents the acid value per gram of resin solids.

[0052] The weight-average molecular weight of the alkali-soluble resin is preferably 400 to 30000. The weight-average molecular weight of the alkali-soluble resin is more preferably 1000 to 15000, even more preferably 2000 to 10000, and even more preferably 2500 to 6000, in terms of good compatibility with metal oxide particles. The above weight-average molecular weight is obtained by measuring it using gel permeation chromatography (GPC) as described in the examples.

[0053] The double bond equivalent of the alkali-soluble resin is preferably 270 to 2000 g / equivalent. More preferably, the double bond equivalent is 300 to 1600 g / equivalent, even more preferably 330 to 1200 g / equivalent, and even more preferably 360 to 1000 g / equivalent, in that curability can be improved. Here, "double bond" refers to a double bond that exhibits radical polymerization. That is, a double bond like the (meth)acryloyl group. Double bonds that are formed, for example, by adding tetrahydrophthalic anhydride to an OH group are not reactive and are therefore not included in the calculation of double bond equivalents.

[0054] The double bond equivalent mentioned above is the mass of solids in the polymer solution per mole of double bonds in the resin. The mass of solids in the polymer solution is the mass of monomer components constituting the resin. The double bond equivalent can be determined by dividing the mass (g) of resin solids in the polymer solution by the amount of double bonds (mol) in the resin.

[0055] The content of the alkali-soluble resin is preferably 3 to 80% by mass, more preferably 5 to 70% by mass, and even more preferably 10 to 60% by mass, based on 100% by mass of the total solid content of the alkali-soluble resin composition of the present invention. In this specification, "total solid content" means the total amount of components that form the cured product (excluding solvents and other substances that volatilize during the formation of the cured product).

[0056] (Manufacturing method) The method for producing the alkali-soluble resin described above is not particularly limited as long as it is a method that can produce an alkali-soluble resin having the structure described above, and can be appropriately selected from known polymerization methods. In particular, in terms of efficiently obtaining the alkali-soluble resin, the method for producing the alkali-soluble resin is preferably a step of reacting a difunctional epoxy compound with an unsaturated monobasic acid (a-1), and a step of reacting the reaction product obtained in step (a-1) with a polybasic acid anhydride (a-2). Each step will be described below.

[0057] Process (a-1) The above method for producing alkali-soluble resin includes a step (a-1) of reacting a difunctional epoxy compound with an unsaturated monobasic acid. By reacting a difunctional epoxy compound with an unsaturated monobasic acid, the epoxy group opens up and a hydroxyl group is generated.

[0058] (Difunctional epoxy compound) The above-mentioned difunctional epoxy compound is a compound having two epoxy groups, and preferably a difunctional epoxy compound P represented by the following formula (4) is mentioned.

[0059] [ka] (In formula (4), R 3 , R 4 , R 5 , and X are the same as those in equation (1) above. 14 (where m represents a divalent organic group, and m represents an integer greater than or equal to 1.)

[0060] The above R 14 Examples of divalent organic groups represented by the above-mentioned R 3 Similar groups to the divalent organic group represented by can be cited, but among them, divalent hydrocarbon groups which may have substituents are preferred, divalent aliphatic hydrocarbon groups which may have substituents are more preferred, alkylene groups which may have substituents are even more preferred, and alkylene groups which are particularly preferred.

[0061] The number of carbon atoms in the above-mentioned divalent hydrocarbon group is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3.

[0062] Examples of substituents mentioned above include groups similar to those described above, but hydroxyl groups are particularly preferred.

[0063] m represents an integer greater than or equal to 1. It is preferable that m be an integer greater than or equal to 2, and more preferably an integer greater than or equal to 3, as this results in a higher refractive index of the resin and improved compatibility with the metal oxide particles described later. Furthermore, it is preferable that m be an integer less than or equal to 5, and more preferably an integer less than or equal to 4, for good solubility in solvents. m represents the average value of the repeating units. If m represents an integer greater than or equal to 2, there are multiple R 4 , R 5 , R 14 , and X may be the same or different.

[0064] The above compound P preferably has an epoxy equivalent of 150 to 1500 g / equivalent, more preferably 160 to 1000 g / equivalent, and even more preferably 170 to 600 g / equivalent. The epoxy equivalents mentioned above can be determined by a method in accordance with JIS K7236:2001, and specifically by the method described in the examples below.

[0065] The above compound P may have a molecular weight distribution, and the weight-average molecular weight of the compound represented by formula (4) is preferably 80 to 20,000, more preferably 100 to 10,000, and even more preferably 150 to 3,000. The weight-average molecular weight mentioned above is a value obtained by measurement using gel permeation chromatography (GPC).

[0066] For the synthesis of the above compound P, known methods can be used, such as the method described in Japanese Patent Publication No. 2016-108562. Generally, it is synthesized by adding epichlorohydrin to a biphenol compound.

[0067] The above compound P can also be obtained as a commercial product, for example, YL6121H, YX4000 (both manufactured by Mitsubishi Chemical), YSLV-120TE (both manufactured by Nippon Steel Chemical & Material), Denacol® EX-251 (manufactured by Nagase ChemteX), etc.

[0068] Furthermore, if m is 3 or greater, the compound P may be a reaction product obtained by reacting a bisphenol compound with compound P' represented by the following formula (4'). In this case, it is preferable that the relationship m = 2m' + p is satisfied between m in formula (4), m' in formula (4') described later, and p in formula (5).

[0069] [ka] (In the formula, R 3 , R 4 , R 5 , R14 a and b are the same as those in equation (4) above. 1 represents a directly bonded or divalent organic group. m' represents an integer greater than or equal to 1.

[0070] The above X 1 Examples of divalent organic groups represented by this formula include the same groups as the divalent organic group represented by X in formula (4) above. The above X 1 It is preferably a direct bond, an alkylene group, or -SO2-, more preferably a direct bond, an alkylene group having 1 to 10 carbon atoms, or -SO2-, and even more preferably a direct bond or -SO2-. In the formula, m' represents an integer greater than or equal to 1. m' is preferably an integer less than or equal to 3, and more preferably 1. If m' is an integer greater than or equal to 2, there are multiple R 4 , R 5 , R 14 , X 1 a and b may be the same or different.

[0071] As the above compound P', for example, a compound obtained by addition synthesis of biphenol with epichlorohydrin, or a commercially available product, can be used.

[0072] The above-mentioned bisphenol compound is not particularly limited as long as it is a compound having two phenolic hydroxyl groups, but preferably, a compound represented by the following formula (5) is mentioned.

[0073] [ka]

[0074] (In the formula, R 15 and R 16 X represents a substituent, either identical or different. 2 represents a direct bond or a divalent organic group. c is R 15 This represents the number of elements, and is an integer from 0 to 4, R 15If there are multiple instances, they may be the same or different. d is R 16 This represents the number of elements, and is an integer from 0 to 4, R 16 If there are multiple values, they may be identical or different. (p represents an integer greater than or equal to 1.)

[0075] The above R 15 and R 16 The substituent represented by is R in formula (4) above. 4 and R 5 Similar groups to the substituents represented by can be listed. c is substituent R 15 This represents the number of elements, and is an integer from 0 to 4, preferably from 0 to 2, and more preferably 0 or 2. d is substituent R 16 This represents the number of elements, and is an integer from 0 to 4, preferably from 0 to 2, and more preferably 0 or 2.

[0076] The above X 2 Examples of divalent organic groups represented by this formula include the same groups as the divalent organic group represented by X in formula (4) above. The above X 2 It is preferably a direct bond, an alkylene group, or -SO2-, more preferably a direct bond, an alkylene group having 1 to 10 carbon atoms, or -SO2-, and even more preferably -SO2-. p represents an integer greater than or equal to 1. Preferably, p is an integer less than or equal to 3, and more preferably 1. If p represents an integer greater than or equal to 2, there are multiple R 15 , R 16 , X 2 c and d may be the same or they may be different.

[0077] Specific examples of the above-mentioned bisphenol compounds include, for example, bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol TMC, bisphenol P, bisphenol PH, and bisphenol Z. In particular, bisphenol A, bisphenol F, and bisphenol S are preferred, and bisphenol S is more preferred, as they are relatively easy to obtain. The above-mentioned bisphenol compounds may be used individually or in combination of two or more.

[0078] The reaction between the above compound P' and the above bisphenol compound can be carried out by mixing these components in a solvent.

[0079] The mixing ratio of compound P' and the bisphenol compound is preferably 10 to 60 parts by mass of the bisphenol compound, more preferably 15 to 55 parts by mass, even more preferably 20 to 50 parts by mass, and most preferably 30 to 40 parts by mass of the bisphenol compound per 100 parts by mass of compound P'.

[0080] Examples of the above solvents include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate, butyl acetate, cellosolve acetate, carbitol acetate, (di)propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; chloroform; dimethyl sulfoxide; and dimethyl carbonate. Among these, esters are preferred, and carbitol acetate and (di)propylene glycol monomethyl ether acetate are more preferred. These solvents may be used individually or in combination of two or more.

[0081] In the above reaction, it is preferable to use a reaction catalyst. Examples of reaction catalysts include tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, and trihexylamine; tertiary phosphines such as triphenylphosphine; quaternary phosphonium salts such as benzyltriphenylphosphonium bromide; and chelate compounds. Among these, tertiary phosphines such as triphenylphosphine are preferred as reaction catalysts because they have excellent activity. Furthermore, using tertiary phosphines can also improve the voltage retention of the resulting cured product. The above reaction catalysts may be used individually or in combination of two or more types.

[0082] The amount of the above reaction catalyst is not particularly limited, but is preferably 0.05 to 5 parts by mass, more preferably 0.07 to 1 part by mass, even more preferably 0.08 to 0.8 parts by mass, and most preferably 0.1 to 0.6 parts by mass, per 100 parts by mass of the above compound P'.

[0083] The above reaction catalyst may be added all at once, in installments, or sequentially in small amounts. However, in order to suppress the decrease in catalytic activity, it is preferable to add it in installments or sequentially in small amounts.

[0084] The reaction temperature for the above reaction is not particularly limited, but is preferably 80 to 150°C, more preferably 85 to 145°C, and even more preferably 90 to 140°C. The reaction time is not particularly limited, but is preferably 2 to 10 hours, more preferably 3 to 9 hours, and even more preferably 4 to 8 hours.

[0085] The above reaction may be carried out in an atmospheric environment or in an inert gas atmosphere such as nitrogen or argon. Of these, an inert gas atmosphere is preferred in that it suppresses catalyst deactivation.

[0086] The compound P, which is the reaction product of the above compound P' and the above bisphenol compound, is preferably a compound represented by the following formula (6). P 2a -P 2b -P 2a (6) (In the formula, P 2a This represents the structure shown in formula (6a) below, and P 2b This represents the structure shown in equation (6b) below.

[0087] [ka]

[0088] In the formula, R 4 , R 5 , R 14 , X 1 , a, b, and m' are the same as those in equation (4') above. 15 , R 16 , X 2 c and d are the same as those in equation (5) above. 17 and R 18 (These represent divalent organic groups, either identical or distinct.)

[0089] The above R 17 and R 18 The divalent organic group represented by is R in formula (4) above. 14 Examples of groups similar to the divalent organic group represented by can be cited, but among them, divalent hydrocarbon groups which may have substituents are preferred, divalent aliphatic hydrocarbon groups which may have substituents are more preferred, alkylene groups which may have substituents are even more preferred, and alkylene groups which are particularly preferred.

[0090] The above R 17 and R 18 The number of carbon atoms in the divalent organic group represented is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. The above R 17 and R 18The substituents of the organic group represented by can be the same groups as those described above, but among them, the hydroxyl group is preferred.

[0091] The above-mentioned bifunctional epoxy compounds may be used individually or in combination of two or more types.

[0092] Furthermore, in the above method for producing alkali-soluble resin, since the reaction product of compound P' and a bisphenol compound can be used as the difunctional epoxy compound (compound P), the method may include a step (step (a-0)) to produce the reaction product described above before step (a-1).

[0093] (unsaturated monobasic acid) Examples of the above-mentioned unsaturated monobasic acids include monobasic acids having one carboxyl group and one or more radically polymerizable unsaturated bonds. Specific examples include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, β-acryloxypropionic acid, reaction products of hydroxyalkyl (meth)acrylates having one hydroxyl group and one (meth)acryloyl group with dibasic acid anhydrides, reaction products of polyfunctional (meth)acrylates having one hydroxyl group and two or more (meth)acryloyl groups with dibasic acid anhydrides, and caprolactone-modified products of these monobasic acids. In particular, due to the good reactivity of the unsaturated double bond, the above unsaturated monobasic acid is preferably a compound having a (meth)acryloyl group, such as acrylic acid or methacrylic acid, more preferably acrylic acid or methacrylic acid, and most preferably methacrylic acid. The above unsaturated monobasic acids may be used individually or in combination of two or more.

[0094] The amount of unsaturated monobasic acid added is preferably such that the acid group content of the unsaturated monobasic acid is 0.6 to 1.4 moles per mole of epoxy group in the difunctional epoxy compound, more preferably 0.7 to 1.3 moles, even more preferably 0.8 to 1.2 moles, and even more preferably 1.0 to 1.1 moles. If epoxy groups remain in the resin, the storage stability of the resin composition may deteriorate.

[0095] The above unsaturated monobasic acid may be added all at once, in installments, or sequentially, but installments or sequential addition are preferred because they can suppress side reactions.

[0096] In the reaction of step (a-1) described above, it is preferable to use an addition catalyst. Examples of the above-mentioned addition catalysts include tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, and trihexylamine; tertiary phosphines such as triphenylphosphine; quaternary phosphonium salts such as benzyltriphenylphosphonium bromide; and chelate compounds. These may be used individually or in combination of two or more. Among these, tertiary phosphines such as triphenylphosphine are preferred as the addition catalyst.

[0097] The amount of the above addition catalyst is not particularly limited, but is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, even more preferably 0.2 to 3 parts by mass, and most preferably 0.5 to 2.5 parts by mass, per 100 parts by mass of the above bifunctional epoxy compound. Note that the amount of catalyst here refers to the total amount including the reaction catalyst if a reaction catalyst is used in step (a-0) above.

[0098] The above addition catalyst may be added all at once, in installments, or sequentially in small amounts, but it is preferable to add it in installments or sequentially in small amounts in order to suppress the decrease in catalytic activity.

[0099] If the addition catalyst used in step (a-1) is the same as the reaction catalyst used in step (a-0), the mass ratio of the catalysts in each step is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 to 90 / 10, even more preferably 15 / 85 to 85 / 15, and even more preferably 20 / 80 to 80 / 20, as [amount of catalyst added in step (a-0) / amount of catalyst added in step (a-1)].

[0100] Furthermore, a polymerization inhibitor may be used in the reaction of step (a-1) described above. By using a polymerization inhibitor, gelation can be suppressed. The polymerization inhibitors mentioned above are not particularly limited and any known ones can be used, for example, benzoquinone, hydroquinones (e.g., hydroquinone, hydroquinone monomethyl ether, p-tert-butylhydroquinone, p-benzoquinone, etc.), phenols (e.g., 2,6-di-t-butyl-4-methylphenol, 6-t-butyl-2,4-dimethylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), etc.), catechols (e.g., p-tert-butylcatechol, etc.), amines (e.g., N,N-diethylhydroxylamine, etc.), 1,1-diphenyl-2-picrylhydrazyl, tri-p-nitrophenylmethyl, phenothiazine, piperidine 1-oxyls (e.g., 2,2,6,6-tetramethylpiperidine 1-oxyl, etc.), oxygen, etc. The polymerization inhibitors mentioned above may be used individually or in combination of two or more.

[0101] As for the reaction conditions in step (a-1) above, the reaction temperature is not particularly limited, but is preferably 80 to 140°C, more preferably 85 to 135°C, and even more preferably 90 to 130°C. The reaction time is not particularly limited, but is preferably 5 to 30 hours, more preferably 6 to 25 hours, and even more preferably 7 to 20 hours.

[0102] Process (a-2) In step (a-2) above, the reactant obtained in step (a-1) above is reacted with a polybasic acid anhydride. In the reaction of step (a-2) above, the polybasic acid anhydride is added to the hydroxyl group of the reactant obtained in step (a-1) above, and the acidic group of the carboxyl group is introduced into the reactant.

[0103] Examples of the polybasic acid anhydrides mentioned above include phthalic anhydride, succinic anhydride, octenyl succinic anhydride, pentadodecenyl succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, dibasic acid anhydrides such as the reaction product of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with itaconic anhydride or maleic anhydride; trimellitic anhydride; aliphatic or aromatic tetrabasic acid dianhydrides such as biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, diphenylethertetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. Among these, tetrahydrophthalic anhydride is preferred. The above polybasic acid anhydrides may be used individually or in combination of two or more types.

[0104] The above polybasic acid anhydride is preferably added in an amount of 0.1 to 1.1 moles, more preferably 0.15 to 1 mole, even more preferably 0.2 to 0.9 moles, and most preferably 0.4 to 0.7 moles, relative to 1 mole of hydroxyl groups in the reactant obtained in step (a-1) above.

[0105] A catalyst may be used in the reaction of step (a-2) described above, if necessary. Examples of catalysts that can be used include those similar to the reaction catalyst described above.

[0106] As for the reaction conditions in step (a-2) above, the reaction temperature is not particularly limited, but is preferably 60 to 150°C, more preferably 70 to 135°C, and even more preferably 80 to 120°C. The reaction time is not particularly limited, but is preferably 1 to 10 hours, more preferably 2 to 9 hours, and even more preferably 3 to 8 hours.

[0107] The above-described method for producing alkali-soluble resin may include other steps in addition to the reaction step described above. Examples of these other steps include a maturation step, a neutralization step, a dilution step, a drying step, a concentration step, and a purification step. These steps can be carried out by known methods.

[0108] (2) Metal oxide particles Examples of metal oxide particles used in the present invention include light-transmitting metal oxide particles with a high refractive index containing atoms such as Be, Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Gd, Tb, Dy, Yb, Lu, Ti, Zr, Hf, Nb, Mo, W, Zn, B, Al, Si, Ge, Sn, Pb, Sb, Bi, and Te. In particular, the above metal oxide particles more preferably contain at least one metal element selected from the group consisting of Ti, Al, Zr, Zn, Sn, Ce, and Si, in order to provide a cured product with a higher refractive index. Furthermore, it is more preferable to include Zr from the viewpoint of providing a cured film with a high dielectric constant, and it is more preferable to include Si from the viewpoint of providing a cured film with high hardness.

[0109] The above metal oxides may be oxides of a single metal, solid solutions of two or more oxides, or complex oxides. Examples of single metal oxides include aluminum oxide (Al2O3), titanium oxide (TiO2), zirconium oxide (ZrO2), indium oxide (In2O3), zinc oxide (ZnO), tin oxide (SnO2), lanthanum oxide (La2O3), yttrium oxide (Y2O3), cerium oxide (CeO2), magnesium oxide (MgO), and silicon oxide (SiO2). Examples of solid solutions of two or more oxides include ITO and ATO. Examples of complex oxides include barium titanate (BaTiO3), titanite (CaTiO3), and spinel (MgAl2O4).

[0110] In particular, the metal oxide particles are preferably zirconium dioxide particles (ZrO2 particles) and / or silicon dioxide particles (SiO2 particles) because they can provide a hardened product with a high refractive index and high dielectric constant or high hardness.

[0111] In the present invention, the metal oxide particles may be surface-modified or unmodified, but surface-modified metal oxide particles are preferable in that they can improve dispersibility in the resin composition. Surface modification makes the surface of the metal oxide particles lipophilic, which prevents particle aggregation and allows for fine dispersion.

[0112] In this specification, surface-modified metal oxide particles are also referred to as "coated metal oxide particles." Furthermore, when metal oxide particles are surface-modified, the mass of the metal oxide particles includes the mass of the surface modifier. In this invention, the organic compound (surface modifier) ​​that modifies the surface of the metal oxide particles may be chemically bonded and / or coordinated, or it may adhere to the metal oxide particles by hydrogen bonding or salt formation. In this invention, "surface modification" includes both states in which the organic group is chemically bonded and / or coordinated to the metal oxide, or physically attached.

[0113] The surface modification of the metal oxide particles can be achieved by known methods such as mixing the metal oxide particles with a surface modifier in a solvent or performing a hydrothermal reaction in the presence of water.

[0114] In the method of mixing the metal oxide particles and the surface modifier in a solvent, the surface modifier used is not particularly limited as long as it is an organic compound that can make the surface of the metal oxide particles lipophilic, thereby preventing particle aggregation and fine dispersion. Examples include organic acids, coupling agents, and surfactants. One or more of these may be used.

[0115] Preferred organic acids include carboxylic acids (compounds having a carboxyl group) with 5 or more carbon atoms. Specific examples include pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, 2-ethylhexanoic acid, 2-methylheptanoic acid, 4-methyloctanoic acid, salicylic acid, naphthenic acid, decanoic acid, undecylic acid, neodecanoic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, pivalic acid, 2,2-dimethylbutyric acid, 3,3-dimethylbutyric acid, 2,2-dimethylvaleric acid, 2,2-diethylbutyric acid, 3,3-diethylbutyric acid, and stearin. Examples include half-esters of C3-9 aliphatic dicarboxylic acids such as acids, pristanic acid, 2-acryloyloxyethylhexahydrophthalic acid, 2-methacryloyloxyethylhexahydrophthalic acid, acrylic acid, methacrylic acid, 2-acryloyloxyethyl succinic acid, and 2-methacryloyloxyethyl succinic acid with (meth)acryloyloxy C1-6 alkyl alcohols; and half-esters of C8-14 aromatic dicarboxylic acids such as 2-acryloyloxyethyl phthalic acid and 2-methacryloyloxyethyl phthalic acid with (meth)acryloyloxy C1-6 alkyl alcohols. The above organic acids may be used individually or in combination of two or more types.

[0116] Examples of the coupling agent include compounds having organic groups that can bond with the metal oxide particles and reactive functional groups that can make the particles lipophilic. Examples of the reactive functional groups include (meth)acryloyloxy groups, epoxy groups, amino groups, vinyl groups, thiol groups, acid anhydride groups, and phenol groups. By surface treatment with a compound having the reactive functional groups, the metal oxide particles can have reactive functional groups such as (meth)acryloyloxy groups, epoxy groups, amino groups, vinyl groups, thiol groups, acid anhydride groups, and phenol groups on their surface, which are derived from the coupling agent. The coupling agents described above may be used individually or in combination of two or more types.

[0117] Examples of the coupling agents mentioned above include silane coupling agents, titanate coupling agents, and aluminate coupling agents. Examples of the above silane coupling agents include (meth)acryloyloxy silane coupling agents such as 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, and 3-(meth)acryloyloxypropyltriethoxysilane; diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. Examples include epoxy silane coupling agents such as ethoxysilane and 3-glycidoxypropyltriethoxysilane; and amino silane coupling agents such as N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane.

[0118] Examples of the titanate-based coupling agents mentioned above include isopropyltriisostearoyl titanate, isopropyldimethacrylateisostearoyl titanate, isopropyltri(dodecyl)benzenesulfonyl titanate, neopentyl(diallyl)oxytri(dioctyl)phosphate titanate, and neopentyl(diallyl)oxytrineododecanoyl titanate.

[0119] Examples of the aluminate-based coupling agents mentioned above include acetalkoxyaluminum diisopropylate.

[0120] Examples of the above-mentioned surfactants include ionic surfactants such as anionic surfactants, cationic surfactants, and amphoteric surfactants, or nonionic surfactants. Only one type of surfactant may be used, or two or more types may be used.

[0121] Examples of the above-mentioned anionic surfactants include fatty acid-based surfactants such as sodium oleate, sodium stearate, sodium laurate, potassium fatty acid, and sodium fatty acid ester sulfonate; phosphate-based surfactants such as alkyl phosphate, alkyl phosphate ester, and sodium alkyl phosphate ester; olefin-based surfactants such as sodium alpha-oleinsulfonate; alcohol-based surfactants such as sodium alkyl sulfate; and alkylbenzene-based surfactants.

[0122] Examples of the cationic surfactants mentioned above include alkylmethylammonium chloride, alkyldimethylammonium chloride, alkyltrimethylammonium chloride, and alkyldimethylbenzylammonium chloride.

[0123] Examples of the above-mentioned amphoteric surfactants include carboxylic acid-based surfactants such as alkylaminocarboxylates and phosphate ester-based surfactants such as phosphobetaines.

[0124] Examples of the nonionic surfactants mentioned above include fatty acid-based surfactants such as polyoxyethylene lanolin fatty acid esters and polyoxyethylene sorbitan fatty acid esters; polyoxyethylene alkylphenyl ethers; fatty acid alkanolamides; and phosphoric acid-based surfactants such as organic phosphate esters, alkyl phosphate esters, phosphate polyesters, and polyoxyalkylene alkyl ether phosphate esters.

[0125] The mixing of the metal oxide particles and the surface modifier may be carried out in a solvent. When mixing the metal oxide particles and the surface modifier in a solvent, the powdered metal oxide particles may be added and mixed into a dispersion of the surface modifier, or the surface modifier may be added and mixed into a dispersion (slurry) of the metal oxide particles, or each dispersion may be prepared separately and then mixed. For example, when preparing a dispersion of zirconium oxide (ZrO2) particles, the amount of dispersion medium used is preferably enough to sufficiently disperse the zirconium oxide particles. For every 100 parts by mass of zirconium oxide particles, the total amount of dispersion medium is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 60 parts by mass or more, and preferably 600 parts by mass or less, more preferably 550 parts by mass or less, and even more preferably 500 parts by mass or less.

[0126] The solvent used in the above-mentioned dispersion, as well as the solvent (dispersion medium) used during the above-mentioned mixing, are not particularly limited, but include, for example, water; alcohols such as methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol; esters such as methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, isobutyl acetate, butyl acetate, isopentyl acetate, pentyl acetate, 3-methoxybutyl acetate, 2-ethylbutyl acetate, cyclohexyl acetate, ethylene glycol monoacetate; glycosides such as ethylene glycol and hexylene glycol. Examples include ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol isopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, butyl methyl ketone, cyclohexanone, methylcyclohexanone, dipropyl ketone, methyl pentyl ketone, and diisobutyl ketone; and toluene. These may be used individually or in combination of two or more.

[0127] The mixing ratio of the metal oxide particles and the surface modifier is not particularly limited and can be appropriately determined by known methods. For example, when using a (silane) coupling agent as the surface modifier, the amount of (silane) coupling agent used is preferably 0.01 to 100 parts by mass, more preferably 1 to 70 parts by mass, and even more preferably 1 to 40 parts by mass, per 100 parts by mass of the metal oxide particles.

[0128] The mixing time and temperature when mixing the metal oxide particles and the surface modifier in a solvent can be appropriately selected from known methods. Furthermore, after mixing, the reaction may be carried out by heating or other means as needed.

[0129] Furthermore, the surface-modified metal oxide particles can also be obtained by carrying out a hydrothermal reaction in the presence of water. One method for carrying out the hydrothermal reaction in the presence of water is to heat a compound that produces a metal oxide through a hydrothermal reaction in the presence of water. Examples of compounds that produce metal oxides through the above hydrothermal reaction include various metal oxide precursors, such as hydroxides, chlorides, oxychlorides, sulfates, acetates, organic acid salts, and alkoxides of various metals, and may also be salts of various metals with carboxylic acids.

[0130] Specific examples of compounds that produce metal oxides through the above hydrothermal reaction include, for example, zirconium-containing compounds such as zirconium hydroxide, zirconium chloride, zirconyl oxychloride, zirconyl oxyacetate, zirconyl oxynitrate, zirconium sulfate, zirconium octanoate, zirconium 2-ethylhexanoate, zirconium oleate oxide, zirconium acetate, zirconium stearate oxide, zirconium laurate oxide, and tetrabutoxyzirconium, as well as other zirconium alkoxides. Examples of titanium-containing compounds include titanium hydroxide, titanium chloride, titanium oxychloride, titanium oxyacetate, titanium oxynitrate, titanium sulfate, titanium octanoate, titanium oleate oxide, titanium acetate, titanium stearate oxide, titanium laurate oxide, and tetrabutoxytitanium (e.g., tetra-n-butoxytitanium), as well as other titanium alkoxides.

[0131] For example, when zirconium 2-ethylhexanoate is subjected to a hydrothermal reaction, zirconium oxide coated with 2-ethylhexanoic acid and / or a carboxylic acid derived from 2-ethylhexanoic acid can be obtained. The reaction conditions in the above hydrothermal reaction, such as the amount of water used, reaction temperature, and reaction time, are not particularly limited and can be appropriately selected from known methods.

[0132] The metal oxide particles whose surfaces have been modified by the hydrothermal reaction described above may be further treated with the surface modifiers (organic acids, coupling agents, surfactants) described above. A method for treating with the surface treatment agents is the same as the method for surface modifying the metal oxide particles with the surface modifiers described above.

[0133] Surface-modified metal oxide particles have an affinity for organic solvents because their surfaces are modified with reactive functional groups. Therefore, they remain stably dispersed as nanoparticles in the various organic solvents mentioned above. Specifically, they can be handled as a highly transparent solution. Surface-modified metal oxide particles (coated metal oxide particles) can usually be used in the form of a dispersion in which the metal oxide particles are dispersed in the surface modification solution used for surface modification, or they can be used as a powder after solvent removal by vacuum distillation.

[0134] In the surface-modified metal oxide particles described above, the amount of surface modifier is preferably 0 to 50 parts by mass, more preferably 1 to 40 parts by mass, and even more preferably 2 to 30 parts by mass, per 100 parts by mass of metal oxide particles. When the amount of surface modifier is within the above range, the refractive index of the alkali-soluble resin composition of the present invention can be further increased, and the hardness and dielectric constant can also be improved.

[0135] The shapes of the metal oxide particles (including surface-modified metal acid particles (coated metal oxide particles); the same applies hereinafter) can be spherical, ellipsoidal, cuboidal, rectangular, pyramidal, needle-shaped, columnar, rod-shaped, cylindrical, flake-shaped, plate-shaped, or flaky. Considering dispersibility in solvents, spherical and columnar shapes are preferred.

[0136] The crystallite size of the metal oxide particles is preferably 20 nm or less. When the crystallite size of the metal oxide particles is within the above range, the transparency of the alkali-soluble resin composition containing the metal oxide particles can be improved. The crystallite size is more preferably 15 nm or less, and even more preferably 10 nm or less. The lower limit of the crystallite size is usually around 1 nm. The crystallite size can be calculated by X-ray diffraction analysis.

[0137] The number-average primary particle diameter of the metal oxide particles is preferably less than 30 nm, and more preferably 25 nm or less. When the number-average primary particle diameter of the metal oxide particles is within the above range, the transparency of the resin composition containing the metal oxide particles can be improved. The above number-mean primary particle diameter is more preferably 20 nm or less, and even more preferably 15 nm or less. The lower limit of the above number-mean primary particle diameter is preferably greater than 1 nm, more preferably 3 nm or more, and even more preferably 5 nm or more.

[0138] The number-mean primary particle diameter mentioned above can be determined by observing metal oxide particles under magnification using a transmission electron microscope (TEM), field emission transmission electron microscope (FE-TEM), or field emission scanning electron microscope (FE-SEM), randomly selecting 100 particles, measuring their lengths along their long axes, and calculating their arithmetic mean.

[0139] There are no particular restrictions on the refractive index of the above metal oxide particles, but from the viewpoint of obtaining a high refractive index, it is preferably 1.70 to 2.70, and more preferably 1.90 to 2.70.

[0140] The specific surface area of ​​the above metal oxide particles is 10 to 400 m². 2 It is preferable that the value be / g, and 20-200m 2 It is even more preferable that the amount be / g, and 30-150m 2 It is most preferable that the value be / g.

[0141] The content of the above-mentioned metal oxide particles is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, and even more preferably 20 to 80% by mass, based on 100% by mass of the total solid content of the alkali-soluble resin composition of the present invention.

[0142] (3) Epoxy (meth)acrylate The alkali-soluble resin composition of the present invention may further contain epoxy (meth)acrylate. Further inclusion of epoxy (meth)acrylate can increase the development speed and improve developability and curing properties.

[0143] The epoxy (meth)acrylate mentioned above is an esterified product of epoxy resin and (meth)acrylic acid.

[0144] The epoxy resin described above is preferably bifunctional, more preferably 2 to 20 functional, even more preferably 2 to 10 functional, and most preferably bifunctional, in terms of improving the crosslinking density of the cured product.

[0145] The epoxy resin mentioned above is not particularly limited as long as it is a compound having an epoxy group, and examples include known aliphatic epoxy resins and aromatic epoxy resins. Among these, aromatic epoxy resins are preferred because they can form a dense cured film and improve electrical insulation. The epoxy resin may be one or more types.

[0146] Examples of the above aromatic epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, naphthol novolac type epoxy resin, naphthol aralkyl type epoxy resin, naphthol-phenol copolymer novolac type epoxy resin, naphthol-cresol copolymer novolac type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, and biphenyl novolac type epoxy resin. Among these, bisphenol A type epoxy resin and cresol novolac type epoxy resin are preferred in terms of good electrical properties, and bisphenol A type epoxy resin is more preferred in terms of superior heat resistance to coloring and the ability to obtain cured products with a higher refractive index. These epoxy resins may have substituents such as halogen atoms, alkyl groups, alkylene groups, cycloalkylene groups, arylene groups, and cyano groups.

[0147] The epoxy resin may have a molecular weight distribution, and the weight-average molecular weight of the epoxy resin is preferably 100 to 30000, more preferably 150 to 2000, and even more preferably 300 to 1000. The weight-average molecular weight mentioned above is a value obtained by measurement using gel permeation chromatography (GPC).

[0148] The epoxy equivalent of the epoxy resin described above is preferably 150 to 5000 g / equivalent, more preferably 170 to 1000 g / equivalent, and even more preferably 200 to 300 g / equivalent, in terms of the excellent properties of the resulting cured product. The epoxy equivalents mentioned above can be determined by a method in accordance with JIS K7236:2001, and specifically by the method described in the examples below.

[0149] The epoxy (meth)acrylate described above preferably has an acidic group. Having an acidic group can further improve the developability of the alkali-soluble resin composition. Examples of the acid groups mentioned above include carboxyl groups, phenolic hydroxyl groups, carboxylic acid anhydride groups, phosphoric acid groups, and sulfonic acid groups. Among these, carboxyl groups are preferred because they have good developability.

[0150] The epoxy (meth)acrylate content is preferably 1 to 70% by mass, more preferably 5 to 60% by mass, and even more preferably 15 to 50% by mass, based on 100% by mass of the total solid content of the alkali-soluble resin composition of the present invention.

[0151] The alkali-soluble resin composition of the present invention preferably further comprises a polymerizable compound and a photopolymerization initiator. (4) Polymerizable compound The polymerizable compounds described above are low-molecular-weight compounds having polymerizable unsaturated bonds (also called polymerizable unsaturated groups) that can be polymerized by irradiation with free radicals, electromagnetic waves (e.g., infrared rays, ultraviolet rays, X-rays, etc.), electron beams, or other active energy rays. Examples include monofunctional compounds having one polymerizable unsaturated group in the molecule and polyfunctional compounds having two or more polymerizable unsaturated groups.

[0152] Examples of the monofunctional compounds mentioned above include N-substituted maleimide monomers; (meth)acrylic acid esters; (meth)acrylamides; unsaturated monocarboxylic acids; unsaturated polycarboxylic acids; unsaturated monocarboxylic acids in which the chain between the unsaturated group and the carboxyl group is extended; unsaturated acid anhydrides; aromatic vinyls; conjugated dienes; vinyl esters; vinyl ethers; N-vinyl compounds; unsaturated isocyanates; and so on. Monomers having active methylene groups or active methine groups can also be used.

[0153] Examples of the polyfunctional compounds mentioned above include the following compounds. Difunctional (meth)acrylate compounds such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, bisphenol A alkylene oxide di(meth)acrylate, and bisphenol F alkylene oxide di(meth)acrylate;

[0154] Trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, ethylene oxide-added ditrimethylolpropane tetra(meth)acrylate, ethylene oxide-added pentaerythritol tetra(meth)acrylate, ethylene oxide-added dipentaerythritol hexa(meth)acrylate, propylene oxide-added trimethylolpropane Dimethylolpropane tetra(meth)acrylate, propylene oxide-added ditrimethylolpropane tetra(meth)acrylate, propylene oxide-added pentaerythritol tetra(meth)acrylate, propylene oxide-added dipentaerythritol hexa(meth)acrylate, ε-caprolactone-added trimethylolpropane tri(meth)acrylate, ε-caprolactone-added ditrimethylolpropane tetra(meth)acrylate, ε-caprolactone-added pentaerythritol tetra(meth)acrylate, ε-caprolactone-added dipentaerythritol hexa(meth)acrylate, dipentaerythritol pentaacrylate succinate modified, pentaerythritol triacrylate succinate modified, dipentaerythritol pentaacrylate phthalate modified, pentaerythritol triacrylate phthalate modified, the following formula:

[0155] [ka]

[0156] Polyfunctional (meth)acrylate compounds with three or more functions, such as modified dipentaerythritol hexaacrylate represented by [formula];

[0157] Polyfunctional vinyl ethers such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexanyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, and ethylene oxide-added dipentaerythritol hexanyl ether;

[0158] Vinyl ether group-containing (meth)acrylic acid esters such as (meth)acrylate 2-vinyloxyethyl, (meth)acrylate 3-vinyloxypropyl, (meth)acrylate 1-methyl-2-vinyloxyethyl, (meth)acrylate 2-vinyloxypropyl, (meth)acrylate 4-vinyloxybutyl, (meth)acrylate 4-vinyloxycyclohexyl, (meth)acrylate 5-vinyloxypentyl, (meth)acrylate 6-vinyloxyhexyl, (meth)acrylate 4-vinyloxymethylcyclohexylmethyl, (meth)acrylate p-vinyloxymethylphenylmethyl, (meth)acrylate 2-(vinyloxyethoxy)ethyl, (meth)acrylate 2-(vinyloxyethoxyethoxyethoxy)ethyl;

[0159] Ethylene glycol diallyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, propylene glycol diallyl ether, butylene glycol diallyl ether, hexanediol diallyl ether, bisphenol A alkylene oxide diallyl ether, bisphenol F alkylene oxide diallyl ether, trimethylolpropane triallyl ether, ditrimethylolpropane tetraallyl ether, glycerin triallyl ether, pentaerythritol tetraallyl ether, dipentaerythritol pentaallyl ether, dipentaerythritol hexaallyl ether, ethylene oxide-added trimethylolpropane triallyl ether, eth Polyfunctional allyl ethers such as ditrimethylolpropanetetraallyl ether with ethylene oxide, pentaerythritol tetraallyl ether with ethylene oxide, and dipentaerythritol hexaallyl ether with ethylene oxide;

[0160] Allyl group-containing (meth)acrylic acid esters such as (meth)acrylate; polyfunctional (meth)acryloyl group-containing isocyanurates such as tri(acryloyloxyethyl)isocyanurate, tri(methacryloyloxyethyl)isocyanurate, alkylene oxide-added tri(acryloyloxyethyl)isocyanurate, alkylene oxide-added tri(methacryloyloxyethyl)isocyanurate; polyfunctional allyl group-containing isocyanurates such as triallyl isocyanurate; polyfunctional urethane (meth)acrylates obtained by the reaction of polyfunctional isocyanates such as tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate with hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; polyfunctional aromatic vinyls such as divinylbenzene; etc. These polymerizable compounds may be used individually or in combination of two or more.

[0161] Among the polymerizable compounds mentioned above, it is preferable to use a polyfunctional polymerizable compound from the viewpoint of further improving the curability of the alkali-soluble resin composition. The number of functions in the polyfunctional polymerizable compound is preferably 3 or more, and more preferably 4 or more. Furthermore, the number of functions is preferably 10 or less, and more preferably 8 or less. The molecular weight of the polymerizable compound is not particularly limited, but from the viewpoint of handling, for example, 2000 or less is preferred.

[0162] Among the polyfunctional polymerizable compounds mentioned above, from the viewpoint of reactivity, economy, and availability, preferred are compounds having a (meth)acryloyl group, such as polyfunctional (meth)acrylate compounds, polyfunctional urethane (meth)acrylate compounds, and (meth)acryloyl group-containing isocyanurate compounds, and more preferably polyfunctional (meth)acrylate compounds. By including a compound having a (meth)acryloyl group, the alkali-soluble resin composition becomes more photosensitive and curable, and a cured product with even higher hardness and transparency can be obtained. It is even more preferable to use a polyfunctional (meth)acrylate compound with three or more functions as the polyfunctional polymerizable compound.

[0163] The content of the polymerizable compound is preferably 1 to 70% by mass, more preferably 5 to 60% by mass, and even more preferably 10 to 50% by mass, based on 100% by mass of the total solid content of the alkali-soluble resin composition of the present invention.

[0164] (5) Photopolymerization initiator The polymerization initiators mentioned above preferably include photopolymerization initiators, and more preferably radical polymerizable photopolymerization initiators.

[0165] Specific examples of the above photopolymerization initiators include, for example, aminoketone compounds such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one ("IRGACURE 907", BASF), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 ("IRGACURE 369", BASF), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one ("IRGACURE 379", BASF); 2,2-dimethoxy-1,2-diphenylethane-1-one ("IRGACURE 651", BASF), and phenylglyoxylic acid methyl ester ("DAROCURE 651"). Benzyl ketal compounds such as "MBF" (manufactured by BASF); 1-hydroxy-cyclohexyl-phenyl-ketone ("IRGACURE184", manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propan-1-one ("DAROCUR1173", manufactured by BASF), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one ("IRGACURE2959", manufactured by BASF), 2-hydroxy Hydroketone compounds such as -1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methylpropan-1-one ("IRGACURE 127", manufactured by BASF), [1-hydroxy-cyclohexyl-phenyl-ketone + benzophenone] ("IRGACURE 500", manufactured by BASF); and other alkylphenone compounds exemplified in paragraphs

[0084] to

[0086] of Japanese Patent Application Publication No. 2013-227485;1,2-Octanedione, 1-[4-(phenylthio)phenyl]-,2-(O-benzoyl oxime) ("OXE01", manufactured by BASF), Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime) ("OXE02", manufactured by BASF), 1,2-Octanedione, 1-[4-(phenylthio)-,2-,(O-benzoyl oxime)], Ethanone ("OXE03", manufactured by BASF), 1-[9-ethyl Examples include oxime ester compounds such as -6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime) ("OXE04", manufactured by BASF); benzophenone compounds; benzoin compounds; thioxanthone compounds; halomethylated triazine compounds; halomethylated oxadiazole compounds; biimidazole compounds; titanocene compounds; benzoic acid ester compounds; acridine compounds, etc.; phosphine oxide compounds; etc. Among these, aminoketone compounds and oxime ester compounds are preferred. The above photopolymerization initiators may be used individually or in combination of two or more.

[0166] The content of the above-mentioned photopolymerization initiator is preferably 0.3 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass, based on 100% by mass of the total solid content of the alkali-soluble resin composition of the present invention.

[0167] (6) Other ingredients The alkali-soluble resin composition described above may optionally contain other components besides those mentioned above. Examples of these other components include solvents; colorants (pigments, dyes); dispersants; heat resistance improvers; leveling agents; developing aids; inorganic fine particles such as silica fine particles; coupling agents such as silane, aluminum, and titanium; thermosetting resins such as fillers, phenolic resins, and polyvinylphenols; polymerizable compounds; curing aids such as polyfunctional thiol compounds; plasticizers; polymerization initiators; polymerization inhibitors; ultraviolet absorbers; antioxidants; matting agents; defoamers; antistatic agents; slip agents; surface modifiers; thixotropes; thixotrope aids; quinone diazide compounds; polyvalent phenolic compounds; cationic polymerizable compounds; and thermoacid generators. These may be used individually or in combination of two or more. These other components can be appropriately selected from known components, and their amounts can also be appropriately set.

[0168] (Preparation of alkali-soluble resin composition) The alkali-soluble resin composition described above can be prepared by mixing the alkali-soluble resin, metal oxide particles, and, if necessary, other components described above, using a known method.

[0169] 2.Cured product A cured product obtained by curing the alkali-soluble resin composition of the present invention is also part of the present invention. The cured product of the present invention can have a high refractive index of 1.60 or higher. The refractive index is more preferably 1.63 or higher, and even more preferably 1.65 or higher. The refractive index can be determined by measurement by the method described in the examples below.

[0170] The method for curing the alkali-soluble resin composition of the present invention to obtain a cured product is not particularly limited, and any known method may be used. For example, the alkali-soluble resin composition may be applied to a substrate or molded, and then cured by heating, irradiation with active energy rays such as ultraviolet light, or a combination thereof to obtain a cured product.

[0171] A preferred method for curing the alkali-soluble resin composition is one that includes, for example, the steps of: applying the alkali-soluble resin composition to a substrate to form a coating film (1); irradiating the formed coating film with light (2); and developing and removing the unirradiated portion (3). Typically, a heating step is performed after the exposure step (3) described above. This is because heating increases the density of the cured product, resulting in a high refractive index. However, using the alkali-soluble resin composition of the present invention, a cured product with a high refractive index can be obtained without a heating step after exposure. Therefore, using the alkali-soluble resin composition of the present invention, a cured product with a high refractive index can be obtained at a low temperature.

[0172] The above-mentioned substrate is not particularly limited and can be appropriately selected according to the purpose and application. Examples include substrates made of various materials such as glass plates and plastic plates.

[0173] In step (1) above, the method for applying the alkali-soluble resin composition to form a coating film is not particularly limited and can be carried out by known methods such as spin coating, slit coating, roll coating, and casting. In the curing method described above, it is preferable to apply the alkali-soluble resin composition onto a substrate and then dry the coated material to form a coating film. The drying can be carried out by known methods, such as using a hot plate, IR oven, or convection oven. The drying conditions are appropriately selected according to the boiling point of the solvent components, the type of curing component, the film thickness, the performance of the dryer, etc., but it is generally preferable to dry at a temperature of 50 to 160°C for 10 to 300 seconds.

[0174] In step (2) above, the method of irradiating the formed coating with light is not particularly limited and can be carried out by known methods. Examples of light sources for the active light used for light irradiation include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, medium-pressure mercury lamps, low-pressure mercury lamps, carbon arcs, and fluorescent lamps, as well as laser light sources such as argon ion lasers, YAG lasers, excimer lasers, nitrogen lasers, helium-cadmium lasers, and semiconductor lasers.

[0175] When irradiating the above coating with light, the light irradiation may be performed via a photomask. As the photomask, it is preferable to use a mask with light-shielding sections formed according to the desired pattern.

[0176] In step (3) above, after the light irradiation step described above, the material is developed with a developer to remove the unirradiated areas. Due to the light irradiation, the irradiated areas harden, and the hardened material becomes insoluble or sparingly soluble in the developer. On the other hand, the unirradiated areas dissolve in the developer and are removed by the development process, resulting in a patterned hardened film. The development process can usually be carried out at a development temperature of 10 to 50°C using methods such as immersion development, spray development, brush development, or ultrasonic development.

[0177] The developer used in step (3) above is not particularly limited as long as it dissolves the alkali-soluble resin composition, but usually an organic solvent or an alkaline aqueous solution is used, and a mixture thereof may also be used. When an alkaline aqueous solution is used as the developer, it is preferable to wash with water after development. Examples of organic solvents and alkaline aqueous solutions include those similar to those described in Japanese Patent Application Publication No. 2015-157909.

[0178] Furthermore, the process may include a step (4) of heating the light-irradiated coating after step (3) above. The heating temperature in step (4) above is preferably 260°C or lower, and more preferably 200°C or lower. As for the lower limit of the heating temperature, it is preferably 70°C or higher, and more preferably 90°C or higher, in order to maintain curability.

[0179] The heating time in the above heating process is not particularly limited, but is preferably 5 to 60 minutes. The heating method is also not particularly limited and can be carried out using known heating equipment such as a hot plate, convection oven, or high-frequency heater.

[0180] When the cured product obtained by the above curing method is a cured film, its thickness is preferably 0.1 to 50 μm, more preferably 0.5 to 40 μm, and even more preferably 1 to 30 μm, in order to fully exhibit its film properties.

[0181] 3.Applications The alkali-soluble resin composition of the present invention can yield a cured product with a high refractive index, and is therefore suitable for use in applications requiring a high refractive index. The alkali-soluble resin composition of the present invention is preferably used for forming high-refractive-index transparent films. In particular, in resist applications, a high refractive index improves light extraction efficiency, making the alkali-soluble resin composition of the present invention particularly suitable. Furthermore, the alkali-soluble resin composition of the present invention can be suitably used in applications where a fast development speed and developability are required.

[0182] The alkali-soluble resin composition of the present invention can be used, for example, in magnetic recording materials, catalyst materials, ultraviolet absorbing materials, dental materials, contact lenses, intraocular lenses, high-refractive index lenses for eyeglasses, optical computing, optical memory media, anti-reflective coatings, conformal coatings, microlens arrays, automotive topcoats, paints, coating agents, hair cosmetics, gradient refractive index optical components and dynamic gradient refractive index components, nanoimprint materials, photocurable plastics, polymerizable compounds for hologram recording, glass surface coating materials, transparent coating materials for solar cells, plastic lenses, printing plates, semiconductor light-emitting elements (light-emitting diodes, organic light-emitting diodes, laser diodes), and light guides. The present invention can be widely applied to various applications such as semiconductor elements, light diffusion members, prism sheets, hard coat materials, optical wiring members, diffraction gratings, sealing materials for LEDs, pressure-sensitive adhesives, glass used in sensor elements such as CCD / CMOS and display elements such as displays, protective films used on the surface of films and sheets, photocurable resins (OCR) used for bonding image display members such as liquid crystals to plastic cover panels, reflective protective films used for transparent electrodes, index matching for preventing the bone structure of ITO electrodes in touch panels, antiblocking layers, anti-reflective films for displays, and interlayer insulating films for semiconductors. In particular, the alkali-soluble resin composition of the present invention is suitable for use in microlens arrays and nanoimprint materials because the resin is flexible. Furthermore, the alkali-soluble resin composition of the present invention is particularly suitable as a curable resin composition for optical materials, and can provide a cured film with excellent transparency, substrate adhesion, and electrical properties, for example.

[0183] In this invention, "optical material" refers to a material used as a component of devices in the optical or electrical / electronic fields. For example, it refers to a material used in color filters, light extraction layers, black matrices, photospacers, black column spacers, photoresists, overcoats, planarization layers for TFTs, insulating films for TFTs, and surface coatings for optical lenses used in liquid crystal, organic EL, quantum dot, mini / micro LED display devices, solid-state image sensors, and touch panel display devices. The resin composition of this invention is suitable for use in applications where photolithography is applied due to its alkali solubility, and in addition to its high refractive index, it can become a cured film with high hardness, high transparency, and high dielectric constant. Therefore, it is most preferable to use a curable resin composition for color filters, light extraction layers, and color conversion layers for organic EL display devices. Various light sources can be used for the light extraction layer, such as LEDs, mini / micro LEDs, and quantum dots, but organic EL is preferred because it can be made flexible. A specific example of a light extraction layer for organic EL is the configuration described in Japanese Patent Application Publication No. 2021-34545, and the alkali-soluble resin composition of the present invention can be suitably used as a highly refractive member that is photolithographic and highly transparent. [Examples]

[0184] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0185] The various evaluation methods used in this embodiment are as follows.

[0186] <Acid value> 3 g of the resin solution was accurately weighed and dissolved in a mixed solvent of 90 g of acetone and 10 g of water. The solution was then titrated using a 0.1 N KOH aqueous solution as the titrant. The titration was performed using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.). The acid value per gram of solid content (mgKOH / g) was determined from the acid value of the resin solution and the solid content of the resin solution. The solid content of the resin solution was determined by the following method. That is, approximately 1 g of the resin solution was weighed into an aluminum cup, about 3 g of acetone was added and dissolved, and then it was naturally dried at room temperature. Then, using a hot air dryer (product name: PHH-101, manufactured by Espec Corporation), it was dried at 160 °C for 1.5 hours under vacuum, cooled in a desiccator, and the mass was measured. From the mass reduction amount, the solid content (mass %) of the resin solution was calculated.

[0187] <Double bond equivalent (g / equivalent)> It was determined by dividing the mass (g) of the solid content of the resin solution by the double bond amount (mol) of the resin.

[0188] <Identification of the crystal state of metal oxide particles> The identification of the crystal state of metal oxide particles was carried out using an X-ray diffractometer (RINT-TTRIII, manufactured by Rigaku Corporation).

[0189] <Number average primary particle diameter of metal oxide particles> The number average primary particle diameter of metal oxide particles was measured by observing with a high-resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation). Metal oxide particles were observed at a magnification of 150,000 times, and for 100 randomly selected particles, the length in the major axis direction of each particle was measured, and the average value was taken as the number average primary particle diameter.

[0190] <Measurement of mass reduction rate> Using a TG-DTA (thermogravimetry-differential thermal analysis) apparatus, the metal oxide particles surface-modified from room temperature to 800 °C at a rate of 10 °C / min were heated under an air atmosphere, and the mass reduction rate of the particles was measured. From this mass reduction rate, the proportion of the compound surface-modifying the metal oxide particles and the proportion of the metal oxide particles can be known.

[0191] <Refractive index> The obtained alkali-soluble resin composition was uniformly applied onto a 5 cm square glass substrate (soda lime glass AS-2K, manufactured by ToShin Riko Co., Ltd.) using a spin coater (manufactured by Mikasa Co., Ltd., 1H-D7). The coated plate was dried at 90 °C for 5 minutes to obtain a laminate with a coating film (thickness: 1 μm) formed on the glass substrate. This was exposed with a UV aligner (manufactured by Dainippon Kagaku Kenkyusho Co., Ltd., product name "MA-1100") equipped with a 2.0 kW ultra-high pressure mercury lamp at 100 mJ / cm 2 (in terms of 365 nm illuminance conversion), and then the refractive index of the obtained laminate was measured using a surface roughness meter (manufactured by Hishikawa Shisutemu Co., Ltd., product name "VertScan2.0").

[0192] <Epoxy group quantification> It was measured by a method conforming to JIS K7236:2001. That is, 0.5 g of the resin solution was precisely weighed into a beaker, 25 ml of chloroform, 75 ml of acetic acid, and 2 g of tetraethylammonium bromide were added and stirred for dissolution, and titration was performed with a 0.1 N perchloric acid-acetic acid standard solution using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.) to calculate the mass of the resin solution containing 1 equivalent of epoxy groups.

[0193] <Developability test> The resin solution was spin-coated onto a 10 cm square glass substrate, heat-treated (90 °C, 3 minutes), and then exposed through a photomask with an opening of 30 μm line and space at a distance of 50 μm from the coating film using a UV aligner (manufactured by Dainippon Kagaku Kenkyusho Co., Ltd., product name "MA-1100") equipped with a 2.0 kW ultra-high pressure mercury lamp at an exposure dose of 60 mJ / cm 2 (in terms of 365 nm illuminance conversion). The developability was evaluated by spraying a 0.05% potassium hydroxide aqueous solution with a spin developer, dissolving and removing the unexposed portion, and washing the remaining exposed portion with pure water for 10 seconds for development. Specifically, the coating film developed through the photomask as described above was observed with a surface roughness meter (manufactured by Hishikawa Shisutemu Co., Ltd., product name "VertScan2.0"), and the spraying time of the 0.05% potassium hydroxide aqueous solution required for the unexposed portion to flow was taken as the development time.

[0194] <Preparation of metal oxide particles> Manufacturing Example 1 (Production of coated zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid (coated ZrO2 particles 1)) 782 g of zirconium 2-ethylhexanoate mineral spirit solution (44% by mass zirconium 2-ethylhexanoate, manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was mixed with pure water (268 g). The resulting mixture was placed in an autoclave equipped with a stirrer, and the atmosphere inside the autoclave was replaced with nitrogen gas. The mixture was then heated to 180°C and maintained at this temperature for 16 hours (autoclave pressure of 0.94 MPa) to allow the reaction to occur and produce zirconium oxide particles. Subsequently, the mixture was removed after the reaction, the precipitate accumulated at the bottom was filtered off and washed with acetone, and then dried. When the dried precipitate (100 g) was dispersed in toluene (800 mL), a cloudy solution was obtained. Next, as a purification step, the solution was filtered again using quantitative filter paper (Advantec Toyo Co., Ltd., No. 5C) to remove coarse particles from the precipitate. Furthermore, white zirconium oxide nanoparticles 1 (coated ZrO2 particles 1) were recovered by concentrating the filtrate under reduced pressure to remove toluene.

[0195] Upon examining the crystal structure of the obtained coated ZrO2 particles 1, diffraction lines attributed to tetragonal and monoclinic crystals were detected. Based on the intensity of the diffraction lines, the ratio of tetragonal to monoclinic crystals was 54 / 46, and the particle size (crystallite size) was 5 nm.

[0196] The average particle size (number-mean primary particle size) of coated ZrO2 particles 1, as measured by electron microscopy, was 12 nm. Furthermore, analysis of the obtained coated ZrO2 particles 1 by infrared absorption spectroscopy revealed absorption originating from CH and absorption originating from COOH. These absorptions are thought to be due to 2-ethylhexanoic acid and / or carboxylates derived from 2-ethylhexanoic acid that coat the surface of coated ZrO2 particles 1. Furthermore, the mass loss rate of coated ZrO2 particles 1, measured according to the <measurement of mass loss rate> described above, was 12% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid, which coats the surface of coated ZrO2 particles 1, account for 12% by mass of the entire coated ZrO2 particle 1.

[0197] Manufacturing Example 2 (Production of zirconium oxide nanoparticles coated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid and 2-acryloyloxyethyl succinate (coated ZrO2 particles 2)) The coated ZrO2 particles 1 (10 g) obtained in the above Production Example 1 and 2-acryloyloxyethyl succinate (1.5 g) were stirred and mixed in propylene glycol monomethyl ether acetate (12 g) until uniformly dispersed. Next, n-hexane (36 g) was added to agglomerate the dispersed particles and make the solution cloudy, and the agglomerated particles were separated from the cloudy liquid using filter paper. Subsequently, the separated agglomerated particles were added to n-hexane (36 g), stirred for 10 minutes, and the agglomerated particles were separated using filter paper. The resulting particles were vacuum-dried at room temperature to prepare zirconium oxide nanoparticles (coated ZrO2 particles 2) surface-treated with 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid and 2-acryloyloxyethyl succinate.

[0198] The obtained coated ZrO2 particles 2 were dispersed in deuterated chloroform and used as a sample for analysis, which was performed by 1H-NMR. As a result, it was found that the molar ratio of carboxylate derived from 2-ethylhexanoic acid and / or 2-ethylhexanoic acid to 2-acryloyloxyethyl succinate was 24:76.

[0199] The mass loss rate of coated ZrO2 particles 2, measured according to the above <Measurement of Mass Loss Rate>, was 18% by mass. Therefore, it was found that 2-ethylhexanoic acid and / or carboxylate derived from 2-ethylhexanoic acid, and 2-acryloyloxyethyl succinate, which coat the coated zirconium oxide particles, account for 18% by mass of the total coated zirconium oxide particles.

[0200] A zirconia particle dispersion was obtained by mixing the coated ZrO2 particles 2 (7g) obtained above, methyl ethyl ketone (3g), and DISPER BYK-111 (manufactured by Big Chemie Japan, 0.14g) and uniformly stirring the mixture. The number-average primary particle diameter of the coated ZrO2 particles 2, as measured by electron microscopy, was 12 nm.

[0201] (Synthesis Example 1) Synthesis of resin solution (A-1) In a container equipped with a stirrer, thermometer, reflux condenser, and gas inlet tube, 188 parts of 3,3',5,5'-tetramethyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl (cas. 85954-11-6, epoxy equivalent 188 g / equivalent, Gardner color number 6), 62.6 parts of bisphenol S, 244.3 parts of propylene glycol monomethyl ether acetate, and 0.3 parts of triphenylphosphine as a reaction catalyst were added, and the mixture was reacted at 140°C for 6 hours. The completion of the reaction between the phenolic hydroxyl group and the epoxy group was confirmed by epoxy group determination. Next, 43.5 parts of methacrylic acid, 0.9 parts of triphenylphosphine as an esterification catalyst, and 0.4 parts of hydroquinone as a polymerization inhibitor were charged, and the mixture was reacted at 120°C for 20 hours. The acid value of the reactant was confirmed to be 1.9 mg KOH / g. Next, 88.1 parts of tetrahydrophthalic anhydride were added and the mixture was reacted at 110°C for 5 hours with stirring. As a result, a resin solution (A-1) containing 61% alkali-soluble resin in a propylene glycol monomethyl ether acetate solution was obtained. Table 1 shows the acid value and double bond equivalents of the obtained resin solution (A-1) on a solid content basis.

[0202] (Synthesis Example 2) Synthesis of resin solution (A-2) In a container equipped with a stirrer, thermometer, reflux condenser, and gas inlet tube, 94 parts of 3,3',5,5'-tetramethyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl, 31.3 parts of bisphenol S, 202.3 parts of propylene glycol monomethyl ether acetate, and 0.5 parts of triphenylphosphine as a reaction catalyst were added, and the mixture was reacted at 140°C for 6 hours. After confirming the completion of the reaction between the phenolic hydroxyl group and the epoxy group by epoxy group determination, 251.8 parts of bisphenol A type epoxy resin (trade name "jER834"; manufactured by Mitsubishi Chemical; epoxy equivalent 248 g / equivalent) and 202.3 parts of propylene glycol monomethyl ether acetate were added and dissolved to obtain a homogeneous solution. Next, the internal temperature was maintained at 110°C, and 0.75 parts of triphenylphosphine as an esterification catalyst and 0.6 parts of methylhydroquinone as a polymerization inhibitor were charged. 110.0 parts of methacrylic acid were then added dropwise for 2 hours using a dropping pump. After the dropwise addition was complete, 0.75 parts of triphenylphosphine, an additional catalyst, was added, and the temperature was raised to 120°C for 15 hours to allow the reaction to proceed. The acid value of the reactant was confirmed to be 2.1 mg KOH / g. Next, 145.9 parts of tetrahydrophthalic anhydride were added and the reaction was carried out at 110°C for 5 hours to obtain a resin solution (A-2) containing 61% of an alkali-soluble resin and a carboxyl group-containing bisphenol A type epoxy acrylate mixture in a propylene glycol monomethyl ether acetate solution. Table 1 shows the acid value and double bond equivalent of the obtained resin solution (A-2) on a solid content basis.

[0203] (Synthesis Example 3) Synthesis of resin solution (A-3) In a container equipped with a stirrer, thermometer, reflux condenser, and gas inlet tube, 93 parts of 3,3',5,5'-tetramethyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl (cas. 85954-11-6, epoxy equivalent 186 g / equivalent, Gardner color number 7), 31.3 parts of bisphenol S, 174.3 parts of propylene glycol monomethyl ether acetate, and 0.5 parts of triphenylphosphine as a reaction catalyst were added and reacted at 140°C for 6 hours. After confirming the completion of the reaction between the phenolic hydroxyl group and the epoxy group by epoxy group determination, 251.8 parts of the same bisphenol A type epoxy resin "jER834" used in Synthesis Example 2 and 174.3 parts of propylene glycol monomethyl ether acetate were added and dissolved to obtain a homogeneous solution. Next, 110.0 parts of methacrylic acid, 1.5 parts of triphenylphosphine as an esterification catalyst, and 0.5 parts of hydroquinone as a polymerization inhibitor were charged and reacted at 120°C for 20 hours, and it was confirmed that the acid value of the reactant was 2.2 mg KOH / g. Then, 59.1 parts of tetrahydrophthalic anhydride were added and reacted at 110°C for 5 hours to obtain a resin solution (A-3) containing 61% of an alkali-soluble resin and a carboxyl group-containing bisphenol A type epoxy acrylate in a propylene glycol monomethyl ether acetate solution. The acid value and double bond equivalent of the obtained resin solution (A-3) on a solid content basis are shown in Table 1.

[0204] (Synthesis Example 4) Synthesis of resin solution (A-4) In a container equipped with a stirrer, thermometer, reflux condenser, and gas inlet tube, 75.2 parts of 3,3',5,5'-tetramethyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl, 25.0 parts of bisphenol S, 135.5 parts of propylene glycol monomethyl ether acetate, and 0.3 parts of triphenylphosphine as a reaction catalyst were added, and the mixture was reacted at 140°C for 6 hours. After confirming the completion of the reaction between the phenolic hydroxyl group and the epoxy group by epoxy group determination, 131.4 parts of cresol novolac type epoxy resin (trade name "EOCN-104S"; manufactured by Nippon Kayaku; epoxy equivalent 219 g / equivalent) and 135.5 parts of propylene glycol monomethyl ether acetate were added and dissolved to obtain a homogeneous solution. Next, 69.6 parts of methacrylic acid, 0.9 parts of triphenylphosphine as an esterification catalyst, and 0.4 parts of methylhydroquinone as a polymerization inhibitor were charged and reacted at 120°C for 20 hours, and it was confirmed that the acid value of the reactant was 1.9 mg KOH / g. Then, 122.7 parts of tetrahydrophthalic anhydride were added and reacted at 110°C for 5 hours to obtain a resin solution (A-4) containing 61% of an alkali-soluble resin and a carboxyl group-containing novolac-type epoxy acrylate mixture in a propylene glycol monomethyl ether acetate solution. The acid value and double bond equivalent of the obtained resin solution (A-4) on a solid content basis are shown in Table 1.

[0205] (Synthesis Example 5) Synthesis of resin solution (A-5) In a container equipped with a stirrer, thermometer, reflux condenser, and gas inlet tube, 248 parts of the same bisphenol A type epoxy resin "jER834" used in Synthesis Example 3, 87.0 parts of methacrylic acid, 278.3 parts of propylene glycol monomethyl ether acetate, 1 part of triphenylphosphine as an esterification catalyst, and 0.4 parts of hydroquinone as a polymerization inhibitor were charged. The mixture was reacted at 120°C for 20 hours, and it was confirmed that the acid value of the reactant was 1.8 mg KOH / g. Next, 100.3 parts of tetrahydrophthalic anhydride were added, and the mixture was reacted at 110°C for 5 hours to obtain a resin solution (A-5) containing 61% carboxyl group-containing bisphenol A type epoxy acrylate in the propylene glycol monomethyl ether acetate solution. The acid value and double bond equivalent of the obtained resin solution (A-5) on a solid content basis are shown in Table 1.

[0206] (Synthesis Example 6) Synthesis of resin solution (A-6) In a container equipped with a stirrer, thermometer, reflux condenser, and gas inlet tube, 188 parts of 3,3',5,5'-tetramethyl-4,4'-bis(glycidyloxy)-1,1'-biphenyl, 87.0 parts of methacrylic acid, 237.4 parts of propylene glycol monomethyl ether acetate, 0.8 parts of triphenylphosphine as an esterification catalyst, and 0.4 parts of hydroquinone as a polymerization inhibitor were charged. The mixture was reacted at 120°C for 20 hours, and the acid value of the reactant was confirmed to be 1.9 mg KOH / g. Next, 96.4 parts of tetrahydrophthalic anhydride were charged, and the mixture was reacted at 110°C for 5 hours with stirring. As a result, a resin solution (A-6) containing 61% alkali-soluble resin in the propylene glycol monomethyl ether acetate solution was obtained. The acid value and double bond equivalent of the obtained resin solution (A-6) on a solid content basis are shown in Table 1.

[0207] (Synthesis Example 7) Synthesis of resin solution (A-7) Into a container equipped with a stirring device, a thermometer, a reflux condenser, and a gas inlet tube, 189 parts of Denacol EX-251 (registered trademark, manufactured by Nagase Chemicals, bisphenol S skeleton epoxy resin, epoxy equivalent 189 g / eq), 87.0 parts of methacrylic acid, 240.6 parts of propylene glycol monomethyl ether acetate, 0.8 parts of triphenylphosphine as an esterification catalyst, and 0.4 parts of hydroquinone as a polymerization inhibitor were charged, and the reaction was carried out at 120 °C for 20 hours. It was confirmed that the acid value of the reaction product reached 1.9 mgKOH / g. Next, 100.3 parts of tetrahydrophthalic anhydride was charged, and the reaction was carried out at 110 °C for 5 hours with stirring. As a result, a resin solution (A-7) containing 61% of an alkali-soluble resin in a propylene glycol monomethyl ether acetate solution was obtained. The acid value and double bond equivalent in terms of solid content of the obtained resin solution (A-7) are shown in Table 1.

[0208] (Synthesis Example 8) Synthesis of Resin Solution (B-1) Into a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube, and a dropping tank inlet, 119.2 parts of propylene glycol monomethyl ether acetate and 50.7 parts of propylene glycol monomethyl ether were charged, purged with nitrogen, and the temperature was raised to 90 °C. On the other hand, a mixture of 55.0 parts of benzyl methacrylate, 45.0 parts of methacrylic acid, and 1.0 part of t-butylperoxy-2-ethylhexanoate stirred and mixed was prepared in dropping tank (A), and a mixture of 2.8 parts of n-dodecyl mercaptan and 15.9 parts of propylene glycol monomethyl ether acetate stirred and mixed was prepared in dropping tank (B). After the reaction vessel reached 90°C, polymerization was carried out by dropwise addition from the dropwise addition vessel over a period of 3 hours while maintaining the same temperature. After the addition was completed, the temperature was maintained at 90°C for 30 minutes, then the temperature was raised to 115°C and aged for 90 minutes. To the obtained base polymer solution, 41.3 parts of glycidyl methacrylate, 0.4 parts of triethylamine, and 0.2 parts of Antige W400 (manufactured by Kawaguchi Chemical Industry Co., Ltd.) were added, and the temperature was raised to 115°C while bubbling with an oxygen / nitrogen mixed gas adjusted to an oxygen concentration of 7% at a rate of 20 ml / min, and the reaction was carried out for 8 hours. After that, it was cooled to room temperature to obtain a resin solution (B-1) containing alkali-soluble resin. The acid value and double bond equivalent of the obtained resin solution (B-1) on a solid content basis are shown in Table 2.

[0209] (Examples 1-7, Comparative Examples 1-3) The refractive index of alkali-soluble resin compositions prepared by mixing the metal oxide particles (coated ZrO2 particles 2) obtained in Production Example 2, the resin solutions obtained in Synthesis Examples 1-8, a photopolymerization initiator (Irgacure OXE02, BASF), and a solvent (propylene glycol monomethyl ether acetate (PGMEA)) according to the formulations shown in Table 3 was evaluated using the method described above. The results are shown in Table 3. Note that the formulation values ​​shown in Table 3 represent the solid content.

[0210] (Examples 8-9, Comparative Example 4) A resin composition was prepared by mixing the alkali-soluble resin composition (solid content) shown in Table 4, Milbase (MB), dipentaerythritol hexaacrylate (DPHA), and photopolymerization initiator (Irgacure 907, BASF) with propylene glycol monomethyl ether acetate (PGMEA) to a solid content of 20%. The developability of the obtained resin composition was evaluated by the method described above. The results are shown in Table 4. The mill base (MB) used was prepared by the following method. (Preparation of mill base) Mill base (MB) was obtained by mixing 12.9 parts of propylene glycol monomethyl ether acetate, 0.4 parts of Disparon DA-7301 as a dispersant, 2.25 parts of CI Pigment Green 58 as a colorant, and 1.5 parts of CI Pigment Yellow 138 as colorants, and dispersing the mixture in a paint shaker for 3 hours.

[0211] [Table 1]

[0212] [Table 2]

[0213] [Table 3]

[0214] [Table 4]

[0215] Table 3 confirms that the alkali-soluble resin composition of the example has a high refractive index. Furthermore, Table 4 confirms that the alkali-soluble resin composition of the example has excellent developability.

Claims

1. An alkali-soluble resin composition characterized by comprising an alkali-soluble resin having a structure represented by the following formula (1) and metal oxide particles having a number-average primary particle diameter greater than 1 nm and less than 30 nm. 【Chemistry 1】 (In formula (1), R １ and R ８ each independently represent a monovalent organic group having a polymerizable double bond. R ２ and R ７ each independently represent a hydrogen atom or a group represented by the following formula (2), and at least one of R ２ and R ７ is a group represented by the following formula (2). R ３ and R ６ each independently represent a divalent organic group. R ４ and R ５ each independently represent a substituent. X represents a direct bond, an alkylene group, or -SO₂-. a represents the number of R ４ and is an integer from 0 to 4, and when there are a plurality of R ４ , they may be the same or different from each other. b represents the number of R ５ and is an integer from 0 to 4, and when there are a plurality of R ５ , they may be the same or different from each other. n represents an integer of 1 or more. When n is an integer of 2 or more, the plurality of R ４ , R ５ , R ６ , R ７ and X may be the same or different from each other. ) 【Chemistry 2】 (In formula (2), R ９ (This represents a divalent organic group that may have substituents.)

2. The alkali-soluble resin composition according to claim 1, characterized in that the metal oxide particles contain at least one metal element selected from the group consisting of titanium, aluminum, zirconium, zinc, tin, cerium, and silicon.

3. The alkali-soluble resin composition according to claim 1 or 2, characterized in that the metal oxide particles are surface-modified metal oxide particles.

4. Furthermore, the alkali-soluble resin composition according to claim 1 or 2 is characterized by containing epoxy (meth)acrylate.

5. Furthermore, the alkali-soluble resin composition according to claim 1 or 2 is characterized by comprising a polymerizable compound and a photopolymerization initiator.

6. The alkali-soluble resin composition according to claim 1 or 2, characterized in that it is for forming a transparent film with a high refractive index.

7. A cured product obtained by curing the alkali-soluble resin composition according to claim 1 or 2.

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