JP7110452B2 - Resin, curable composition, cured product, method for producing cured product, and method for producing microlens - Google Patents

Description

The present invention provides a resin containing a structural unit having a specific structure, a curable composition containing the resin, a cured product obtained by curing the above-mentioned resin, a method for producing a cured product using the above-mentioned resin, and the above-mentioned and a method for manufacturing a microlens using the resin of

BACKGROUND ART Conventionally, curable resin materials have been used in various applications. By selecting the partial structure of the curable resin and the types of additives used together with the curable resin, cured products exhibiting various properties can be formed using the curable resin.
For example, cured products used to form flattening films and microlenses in image display devices and optical devices are sometimes desired to have good transparency, solvent resistance, and a high refractive index. .

As a curable resin used for forming a flattening film or a microlens, for example, a copolymer containing a structural unit containing an epoxy group and a structural unit containing a biphenylyl group is known (see Patent Document 1. reference.).

WO2015/122109

However, when forming a cured film using a resin having an epoxy group as described in Patent Document 1, depending on the type of substrate, it may be difficult to form a sufficiently cured cured film, or the cured film may be formed in a high temperature environment. When used, the thickness of the film may vary, or the light transmittance of the transparent film may decrease.

The present invention has been made in view of the above problems. A thermosetting resin that can form a cured product whose transmittance is difficult to decrease, a curable composition containing the resin, a cured product obtained by curing the above-mentioned resin, and a cured product using the above-mentioned resin and a method of manufacturing a microlens using the above resin.

The present inventors have found that a structural unit having a specific structure having a blocked isocyanate group, a structural unit having a specific structure having a hydroxyl group, and a structural unit having a specific structure having a hydrocarbon group containing two or more benzene rings, The inventors have found that the above problems can be solved by using a resin containing a combination of the above, and have completed the present invention.

（式（ａ１）、（ａ２）、及び（ａ３）中、Ｒ^１は、それぞれ独立に水素原子、又はメチル基であり、Ｒ^２は、単結合、又は炭素原子数１以上５以下のアルキレン基であり、Ｒ^３は、ブロックイソシアネート基であり、Ｒ^４は、２価の炭化水素基であり、Ｒ^５は、単結合、又は２価の連結基であり、Ｒ^６は、２以上のベンゼン環を含む有機基である。） A first aspect of the present invention is a resin containing a structural unit represented by the following formula (a1), a structural unit represented by the following formula (a2), and a structural unit represented by the following formula (a3). be.

(In formulas (a1), (a2), and (a3), R ¹ is each independently a hydrogen atom or a methyl group, and R ² is a single bond or an alkylene group having 1 to 5 carbon atoms. , R ³ is a blocked isocyanate group, R ⁴ is a divalent hydrocarbon group, R ⁵ is a single bond or a divalent linking group, R ⁶ is 2 or more benzene It is an organic group containing a ring.)

A second aspect of the present invention is a curable composition comprising the resin according to the first aspect and a solvent.

A third aspect of the present invention is a cured product obtained by curing the resin according to the first aspect.

A fourth aspect of the present invention is
A molding step of molding the resin according to the first aspect into a predetermined shape;
A curing step of curing the molded resin by heating;
A method for producing a cured product comprising

A fifth aspect of the present invention is
a lens material layer forming step of forming a lens material layer by heating and cross-linking a resin layer obtained by applying a composition containing a resin according to the first aspect onto a substrate;
a lens pattern forming step of forming a lens pattern by forming a resist pattern on the lens material layer and then reflowing the resist pattern by heating to form a lens pattern;
a shape transfer step of dry-etching the lens material layer and the lens pattern using the lens pattern as a mask to transfer the shape of the lens pattern to the lens material layer;
A method of manufacturing a microlens, comprising:

According to the present invention, a curable resin having good curability and capable of forming a cured product having a high refractive index, a curable composition containing the resin, and a cured product obtained by curing the above-mentioned resin. , a method for producing a cured product using the aforementioned resin and a method for producing a microlens using the aforementioned resin can be provided.

（式（ａ１）、（ａ２）、及び（ａ３）中、Ｒ^１は、それぞれ独立に水素原子、又はメチル基であり、Ｒ^２は、単結合、又は炭素原子数１以上５以下のアルキレン基であり、Ｒ^３は、ブロックイソシアネート基であり、Ｒ^４は、２価の炭化水素基であり、Ｒ^５は、単結合、又は２価の連結基であり、Ｒ^６は、２以上のベンゼン環を含む炭化水素基である。） ≪Resin≫
The resin includes a structural unit represented by formula (a1) below, a structural unit represented by formula (a2) below, and a structural unit represented by formula (a3) below.

(In formulas (a1), (a2), and (a3), R ¹ is each independently a hydrogen atom or a methyl group, and R ² is a single bond or an alkylene group having 1 to 5 carbon atoms. , R ³ is a blocked isocyanate group, R ⁴ is a divalent hydrocarbon group, R ⁵ is a single bond or a divalent linking group, R ⁶ is 2 or more benzene It is a hydrocarbon group containing a ring.)

Hereinafter, the structural unit represented by formula (a1) is also referred to as "structural unit A1", the structural unit represented by formula (a2) is also referred to as "structural unit A2", and the structural unit represented by formula (a3) is also referred to as “structural unit A3”.

Structural unit A1 represented by formula ⁽ a1) above has a blocked isocyanate group as R3. A blocked isocyanate group means an isocyanate group blocked with a thermally dissociable protecting group.
Therefore, when the resin having the structural unit A1 is heated, the protecting group in the blocked isocyanate group is eliminated to generate an active isocyanate group.

An isocyanate group generated by heating readily reacts with a functional group having an active hydrogen. Here, the structural unit A2 represented by the above formula (a2) has a hydroxyl group, which is a functional group having an active hydrogen group. Therefore, when the above resin is heated, an active isocyanate group is generated in the structural unit A1. The isocyanate group (--NCO) reacts with the hydroxyl group in the structural unit A2 to promote cross-linking by the urethane bond (--NH--CO--O--) and form a cured product.

Furthermore, the structural unit represented by the above formula (a3) has a hydrocarbon group containing ^two or more benzene rings as R6. Here, the hydrocarbon group containing two or more benzene rings contributes to increasing the refractive index of the cured product.
Therefore, when the above resin is heated, the curing of the resin progresses satisfactorily, resulting in the formation of a cured product with a high refractive index.

The essential or optional structural units contained in the resin, the method for producing the resin, and the like are described below.

<Structural unit A1>
The resin contains structural units A1 having blocked isocyanate groups, as described above. The resin may contain a combination of two or more structural units A1.

Structural unit A1 is a structural unit represented by the above formula (a1). In formula (a1), ^R1 is a hydrogen atom or a methyl group.

In formula (a1), R ² is a single bond or an alkylene group having 1 to 5 carbon atoms. The alkylene group may be linear or branched, preferably linear. Specific examples of the alkylene group for R ² include a methylene group, an ethane-1,2-diyl group, an ethane-1,1-diyl group, a propane-1,3-diyl group and a propane-1,2-diyl group. , butane-1,4-diyl group, and pentane-1,5-diyl group.
Among these groups, a methylene group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, and a pentane-1,5-diyl group are preferred, and methylene group, ethane-1,2-diyl group, and propane-1,3-diyl group are more preferred, and ethane-1,2-diyl group is particularly preferred.

^In formula (a1), R3 is a blocked isocyanate group. As described above, the blocked isocyanate group means an isocyanate group blocked with a thermally dissociable protective group.
Such a thermally dissociable protective group is formed by reacting an isocyanate group with a blocking agent that provides the protective group.

Such blocking agents include, for example, alcohol compounds, phenol compounds, hydroxyl group-containing compounds other than alcohol compounds and phenol compounds, active methylene compounds, amine compounds, imine compounds, oxime compounds, and carbamic acid compounds. , urea-based compounds, acid amide-based (lactam-based) compounds, acid imide-based compounds, triazole-based compounds, pyrazole-based compounds, pyrrole-based compounds, mercaptan-based compounds, and bisulfites.

Examples of alcohol compounds include methanol, ethanol, isopropanol, n-butanol, sec-butanol, 2-ethylhexyl alcohol, 1-octanol, 2-octanol, cyclohexyl alcohol, ethylene glycol, benzyl alcohol, 2,2,2- trifluoroethanol, 2,2,2-trichloroethanol, 2-(hydroxymethyl)furan, 2-methoxyethanol, methoxypropanol, 2-2-ethoxyethanol, n-propoxyethanol, 2-butoxyethanol, 2-(2 -ethoxyethoxy)ethanol, 2-(4-ethoxybutoxy)ethanol, 2-(2-butoxyethoxy)ethanol, N,N-dibutyl-2-hydroxyacetamide, N-morpholineethanol, 2,2-dimethyl-1, 3-dioxolane-4-methanol, 3-oxazolidineethanol, 2-hydroxymethylpyridine, furfuryl alcohol, 12-hydroxystearic acid, 2-hydroxyethyl methacrylate and the like.

Phenolic compounds include, for example, phenol, o-cresol, m-cresol, p-cresol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, 2-n-propylphenol, 3-n-propylphenol , 4-n-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-n-butylphenol, 3-n-butylphenol, 4-n-butylphenol, 2-sec-butylphenol, 3-sec -butylphenol, 4-sec-butylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-n-hexylphenol, 3-n-hexylphenol, 4-n-hexylphenol, 2- (2-ethylhexyl)phenol, 3-(2-ethylhexyl)phenol, 4-(2-ethylhexyl)phenol, 2-n-octylphenol, 3-n-octylphenol, 4-n-octylphenol, 2-n-nonylphenol, 3 -n-nonylphenol, 4-n-nonylphenol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5- Dimethylphenol, 2,3-di-n-propylphenol, 2,4-di-n-propylphenol, 2,5-di-n-propylphenol, 2,6-di-n-propylphenol, 3,4-di-n- propylphenol, 3,5-di-n-propylphenol, 2,3-diisopropylphenol, 2,4-diisopropylphenol, 2,5-diisopropylphenol, 2,6-diisopropylphenol, 3,4-diisopropylphenol, 3, 5-diisopropylphenol, 3-isopropyl-2-methylphenol, 4-isopropyl-2-methylphenol, 5-isopropyl-2-methylphenol, 6-isopropyl-2-methylphenol, 2-isopropyl-3-methylphenol, 4-isopropyl-3-methylphenol, 5-isopropyl-3-methylphenol, 6-isopropyl-3-methylphenol, 2-isopropyl-4-methylphenol, 3-isopropyl-4-methylphenol, 5-isopropyl-4 -methylphenol, 6-isopropyl-4-methylphenol phenol, 2,3-di-n-butylphenol, 2,4-di-n-butylphenol, 2,5-di-n-butylphenol, 2,6-di-n-butylphenol, 3,4-di-n-butylphenol, 3,5 -di-n-butylphenol, 2,3-disec-butylphenol, 2,4-disec-butylphenol, 2,5-disec-butylphenol, 2,6-disec-butylphenol, 3,4-disec-butylphenol , 3,5-disec-butylphenol, 2,3-ditert-butylphenol, 2,4-ditert-butylphenol, 2,5-ditert-butylphenol, 2,6-ditert-butylphenol, 3,4di tert-butylphenol, 3,5-di-tert-butylphenol, 2,3-di-n-octylphenol, 2,4-di-n-octylphenol, 2,5-di-n-octylphenol, 2,6-di-n-octylphenol, 3 ,4-di-n-octylphenol, 3,5-di-n-octylphenol, 2,3-di-2-ethylhexylphenol, 2,4-di-2-ethylhexylphenol, 2,5-di-2-ethylhexylphenol, 2,6 -di-2-ethylhexylphenol, 3,4-di-2-ethylhexylphenol, 3,5-di-2-ethylhexylphenol, 2,3-di-n-nonylphenol, 2,4-di-n-nonylphenol, 2,5-di- n-nonylphenol, 2,6-di-n-nonylphenol, 3,4-di-n-nonylphenol, 3,5-di-n-nonylphenol, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2-bromophenol , 3-bromophenol, 4-bromophenol 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2-fluorophenol, 3-fluorophenol, 4-fluorophenol, styrenated phenol (by α-methylbenzyl group mono-, di-, or tri-substituted phenol), methyl salicylate, methyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, 2-ethylhexyl 4-hydroxybenzoate, 4-[(dimethylamino)methyl]phenol, 4 -[(dimethylamino)methyl]nonylphenol, bis(4-hydroxyphenyl)acetic acid, 2-hydroxypyridine, 2-hydroxyquinoline, 8-hydroxyquinoline, 2-chloro-3-pyridinol, and the like. be done.

Examples of hydroxyl group-containing compounds other than alcoholic compounds and phenolic compounds include N-hydroxysuccinimide and triphenylsilanol.

Examples of active methylene compounds include Meldrum's acid, dialkyl malonate (e.g., dimethyl malonate, diethyl malonate, di-n-butyl malonate, di-tert-butyl malonate, di-2-ethylhexyl malonate, methyl malonate, n-butyl, ethyl n-butyl malonate, sec-butyl methyl malonate, sec-butyl ethyl malonate, tert-butyl methyl malonate, tert-butyl ethyl malonate, diethyl methylmalonate, dibenzyl malonate, malonic acid diphenyl, benzylmethyl malonate, ethylphenyl malonate, tert-butylphenyl malonate, and isopropylidenemalonate, etc.), alkyl acetoacetates (e.g., methyl acetoacetate, ethyl acetoacetate, n-propyl acetoacetate, isopropyl acetoacetate) , n-butyl acetoacetate, tert-butyl acetoacetate, benzyl acetoacetate, and phenyl acetoacetate, etc.), 2-acetoacetoxyethyl methacrylate, acetylacetone, and ethyl cyanoacetate.

Examples of amine compounds include dibutylamine, diphenylamine, aniline, N-methylaniline, carbazole, bis(2,2,6,6-tetramethylpiperidinyl)amine, di-n-propylamine, diisopropylamine, isopropyl ethylamine, 2,2,4-trimethylhexamethyleneamine, 2,2,5-trimethylhexamethyleneamine, N-isopropylcyclohexylamine, dicyclohexylamine, bis(3,5,5-trimethylcyclohexyl)amine, piperidine, 2, 6-dimethylpiperidine, tert-butylmethylamine, tert-butylethylamine, tert-butyl n-propylamine, tert-butyl n-butylamine, tert-butylbenzylamine, tert-butylphenylamine, 2,2,6-trimethyl piperidine, 2,2,6,6-tetramethylpiperidine, (dimethylamino)-2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethyl-4-piperidine, 6-methyl- 2-piperidine, 6-aminocaproic acid and the like.

Examples of imine compounds include ethyleneimine, polyethyleneimine, 1,4,5,6-tetrahydropyrimidine, and guanidine.

Examples of oxime compounds include formaldoxime, acetaldoxime, acetoxime, methylethylketoxime, cyclohexanone oxime, diacetylmonoxime, benzophenone oxime, 2,2,6,6-tetramethylcyclohexanone oxime, diisopropylketone oxime, methyl tert-butyl ketone oxime, diisobutyl ketone oxime, methyl isobutyl ketone oxime, methyl isopropyl ketone oxime, methyl 2,4-dimethylpentyl ketone oxime, methyl 3-ethylheptyl ketone oxime, methyl isoamyl ketone oxime, n-amyl ketone oxime, 2,2,4,4-tetramethyl-1,3-cyclobutanedione monoxime, 4,4'-dimethoxybenzophenone oxime, 2-heptanone oxime and the like.

Carbamic acid compounds include, for example, phenyl N-phenylcarbamate.

Urea-based compounds include, for example, urea, thiourea, and ethylene urea.

Acid amide (lactam) compounds include, for example, acetanilide, N-methylacetamide, acetic amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam, pyrrolidone, 2,5-piperazinedione, and laurolactam. mentioned.

Acid imide compounds include, for example, succinimide, maleic acid imide, and phthalimide.

Triazole compounds include, for example, 1,2,4-triazole and benzotriazole.

Examples of pyrazole compounds include pyrazole, 3,5-dimethylpyrazole, 3,5-diisopropylpyrazole, 3,5-diphenylpyrazole, 3,5-ditert-butylpyrazole, 3-methylpyrazole, 4-benzyl- 3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, 3-methyl-5-phenylpyrazole and the like.

Pyrrole compounds include pyrrole, 2-methylpyrrole, 3-methylpyrrole, 2,4-dimethylpyrrole and the like.

Mercaptan compounds include, for example, n-butylmercaptan, n-dodecylmercaptan, n-hexylmercaptan, thiophenol, and pyridine-2-thiol.

Examples of bisulfites include sodium bisulfite and the like.

（式（ａ１－１）、式（ａ１－２）及び式（ａ１－３）中、Ｒ^１、及びＲ^２は、前記式（ａ１）と同様であり、Ｒ^７は、それぞれ独立に炭素原子数１以上１２以下の有機基であり、Ｒ^８は、それぞれ独立にハロゲン原子又は炭素原子数１以上６以下の有機基であり、Ｒ^９は、それぞれ独立に炭素原子数１以上６以下の有機基であり、ａは、０以上３以下の整数である。） Among the structural units A1 represented by the formula (a1) described above, the following formulas (a1-1) and (a1- 2), or structural units represented by formula (a1-3) are preferred.

(In formula (a1-1), formula (a1-2) and formula (a1-3), R ¹ and R ² are the same as in formula (a1) above, and R ⁷ is each independently a carbon atom an organic group having a number of 1 to 12, each R ⁸ is independently a halogen atom or an organic group having 1 to 6 carbon atoms, and each R ⁹ is independently an organic group having 1 to 6 carbon atoms group, and a is an integer of 0 or more and 3 or less.)

In formula (a1-1), the organic group as R ⁷ includes an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and an alkoxyalkyl group having 2 to 12 carbon atoms. a phenyl group, a phenylalkyl group having 7 to 12 carbon atoms, an acyl group having 2 to 12 carbon atoms, and the like. Among these groups, an alkyl group is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, an alkyl group having 1 to 3 carbon atoms is even more preferable, and a methyl group or an ethyl group is particularly preferable.
Alkyl groups may be straight or branched.
In formula (a1-1), two R ^a7 may be the same or different.

In formula (a1-2), R ^a8 is a substituent on the pyrazolyl group and each independently represents a halogen atom or an organic group having 1 to 6 carbon atoms.
Preferable examples of R ^a8 include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 2 carbon atoms. Above 6 or less aliphatic acyl groups and the like can be mentioned.
R ^a8 is preferably a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and the number of carbon atoms An alkyl group of 1 or more and 3 or less is more preferable, and a methyl group is particularly preferable.
In formula (a1-2), a is an integer of 0 or more and 3 or less, preferably 0 or more and 2 or less.

In formula (a1-3), the organic group represented by R ^a9 includes an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and an alkoxyalkyl group having 2 to 12 carbon atoms. group, phenyl group, phenylalkyl group having 7 to 12 carbon atoms, and the like.
In formula (a1-3), two R ^a9 may be the same or different.

The structural unit A1 is incorporated into the resin by copolymerizing a (meth)acrylic acid ester represented by the following formula (aI) with a monomer that provides another structural unit.
Among the (meth)acrylic acid esters represented by formula (aI), the following formula (aI-1), formula (aI-2), or formula (aI-3) Is preferably a (meth) acrylic acid ester, the following formula (aI-1a), formula (aI-2a), or formula (aI-3a) (meth) acrylic acid ester represented by more preferred.
Structural unit A1 may be present in the resin in block form or randomly. The structural unit A1 is preferably randomly present in the resin because the isocyanate group generated in the structural unit A1 by heating easily reacts favorably with the hydroxyl group.

Preferable specific examples of the (meth)acrylic acid ester that provides the structural unit A1 include the following compounds.

Among these, the following (meth)acrylic acid esters are preferable from the viewpoints of facilitating the production of resins, facilitating the production of resins having good curability, and the like.

The amount of the structural unit A1 in the resin is not particularly limited as long as the object of the present invention is not impaired. From the viewpoint of curability, the content of the structural unit A1 in the resin is preferably 15 mol % or more, more preferably 15 mol % or more and 45 mol % or less, based on the total structural units of the resin. From the viewpoint of achieving both good curability and a high refractive index of the cured product, the content of the structural unit A1 in the resin is preferably 20 mol% or more and 40 mol% or less with respect to the total structural units of the resin. , more preferably 25 mol % or more and 35 mol % or less.

<Structural unit A2>
Structural unit A2 is a structural unit represented by the above formula (a2). In formula (a2), R ¹ is a hydrogen atom or a methyl group.

In formula (a2), ^R4 is a divalent hydrocarbon group. The hydrocarbon group as ^R4 may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a hydrocarbon group having an aliphatic portion and an aromatic portion. From the viewpoint of curability of the resin, ^R4 is preferably a divalent aliphatic hydrocarbon group. When R ⁴ is a divalent aliphatic hydrocarbon group, the structure of the aliphatic hydrocarbon group may be linear, branched, cyclic, or a combination thereof. It may have a structure, and is preferably linear.

The number of carbon atoms in the hydrocarbon group for ^R4 is not particularly limited. When the hydrocarbon group is an aliphatic hydrocarbon group, the number of carbon atoms is preferably 1 or more and 20 or less, more preferably 2 or more and 10 or less, and particularly preferably 2 or more and 6 or less. When the hydrocarbon group is an aromatic group or a hydrocarbon group having an aliphatic portion and an aromatic portion, the number of carbon atoms is preferably 6 or more and 20 or less, more preferably 6 or more and 12 or less.

Specific examples of divalent aliphatic hydrocarbon groups include methylene group, ethane-1,2-diyl group, ethane-1,1-diyl group, propane-1,3-diyl group, propane-1,2- diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane- 1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, and icosane- A 1,20-diyl group can be mentioned.
Among these are methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6- diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane- 1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group octadecane-1,18-diyl group, nonadecane-1,19-diyl group and icosane-1,20-diyl group are preferred, methylene group, ethane-1,2-diyl group, propane-1,3- diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane- 1,9-diyl group and decane-1,10-diyl group are more preferable, and ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1 ,5-diyl group and hexane-1,6-diyl group are more preferred.

Specific examples of divalent aromatic hydrocarbon groups include p-phenylene group, m-phenylene group, o-phenylene group, naphthalene-1,4-diyl group, naphthalene-2,6-diyl group, and naphthalene- A 2,7-diyl group and the like can be mentioned, with p-phenylene group and m-phenylene group being preferred, and p-phenylene group being more preferred.

（式（ａ－ＩＩ）中、Ｒ^１及びＲ^４は、式（ａ２）と同様である。） Structural unit A2 is incorporated into the resin by copolymerizing a (meth)acrylic acid ester represented by the following formula (a-II) with a monomer that provides another structural unit.
Structural unit A2 may be present in the resin in block form or randomly. The structural unit A2 is preferably randomly present in the resin because the isocyanate group generated in the structural unit A1 by heating readily reacts favorably with the hydroxyl group.

(In formula (a-II), R ¹ and R ⁴ are the same as in formula (a2).)

Preferable specific examples of (meth)acrylic acid esters that give structural unit A2 include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4 -hydroxybutyl methacrylate, 4-hydroxyphenyl acrylate, 4-hydroxyphenyl methacrylate, 3-hydroxyphenyl acrylate, and 3-hydroxyphenyl methacrylate.
Among these, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are preferred.

The amount of structural unit A2 in the resin is not particularly limited as long as the object of the present invention is not impaired.
The amount of the structural unit A2 in the resin is preferably 15 mol % or more, more preferably 15 mol % or more and 45 mol % or less, relative to the total structural units of the resin. From the viewpoint of achieving both good curability and a high refractive index of the cured product, the content of the structural unit A1 in the resin is preferably 20 mol% or more and 40 mol% or less with respect to the total structural units of the resin. , more preferably 25 mol % or more and 35 mol % or less.
Further, in the resin, the number of moles of the structural unit A1 and the number of moles of the structural unit A2 are preferably 80/100 or more and 100/80 or less as the number of moles of the structural unit A1/the number of moles of the structural unit A2, and 90/ 100 or more and 100/90 or less is more preferable, and 95/100 or more and 100/95 or less is particularly preferable. Most preferably, the number of moles of the structural unit A1 and the number of moles of the structural unit A2 in the resin are equimolar.

<Structural unit A3>
Structural unit A3 is a structural unit represented by the above formula (a3). In formula (a3), R ¹ is a hydrogen atom or a methyl group.

^In formula (a3), R6 is an organic group containing two or more benzene rings. A cured product having a high refractive index can be formed by containing the structural unit A3 having an organic group containing ^two or more benzene rings as R6.
Two or more benzene rings contained in R ⁶ may be fused together, or may be bonded by a single bond or a linking group.
The number of carbon atoms in R6 is not particularly limited as long as the object of the present invention is not ^impaired . The number of carbon atoms in R6 is preferably 10 or more and 50 or less, more preferably 10 or more and 30 or less.

The organic group containing two or more benzene rings as R ⁶ is a group obtained by removing one hydrogen atom from the following polycyclic compound or a compound in which a substituent is introduced into the following polycyclic compound. mentioned. In the following formula, X is -O-, -S-, -CO-, -SO ₂ -, -CO-NH-, -CO-NH-CO-, -NH-CO-NH-, -CO-O- , —CO—O—CO—, —O—CO—O—, —SO ₂ , —NH—, —S—S—, —CH ₂ —, —CH(CH ₃ )—, or —C(CH ₃ ) ₂ -.

Examples of substituents that can be introduced into the polycyclic compound include halogen atoms, alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 3 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, group, an aliphatic acyl group having 2 to 6 carbon atoms, a nitro group, a cyano group, and the like.
When substituents are introduced into the above polycyclic compound, the number of substituents is not particularly limited, but is preferably 4 or less, preferably 1 or 2.

As R ⁶ explained above, a group represented by the following formula is preferable.
In the following formula, R ¹⁰ , R ¹¹ , and R ¹³ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and 1 or more carbon atoms. A group selected from the group consisting of an alkoxy group having 6 or less, an aliphatic acyl group having 2 to 6 carbon atoms, a nitro group, and a cyano group, and R ¹² is a hydrogen atom or 1 to 6 carbon atoms b and c are each independently an integer of 0 or more and 4 or less, and d is an integer of 0 or more and 7 or less.

Among these groups, the group represented by the following formula is preferable because it has a good effect of increasing the refractive index and is easy to introduce into the resin, and in the following formula, two b are A biphenylyl group in which both are 0 is more preferred.

The group R ⁶ described above is attached to the main chain of the resin via R ⁵ . ^R5 is a single bond or a divalent linking group.
The divalent linking group is not particularly limited as long as it does not impair the object of the present invention. Preferable examples of the divalent linking group include an alkylene group having 1 to 6 carbon atoms, -O-, -S-, -CO-, -SO ₂ -, -CO-NH-, -CO-NH -CO-, -NH-CO-NH-, -CO-O-, -CO-O-CO-, -O-CO-O-, -SO ₂ , -NH-, and -S-S- A divalent group selected from the group and a group obtained by combining two or more divalent groups selected from the above groups are included.
Among R ⁶ , a single bond, an alkylene group having 1 to 6 carbon atoms, and -CO-O- are preferable, and a single bond and -CO-O- are more preferable, and -CO-O-* (* is , in formula (a3), represents the end of the bond that binds to R ⁶ ) is particularly preferred. When ^R6 is an alkylene group, the alkylene group may be linear or branched.

From the above, a structural unit represented by the following formula (a3-1) is preferable as the structural unit A3. In formula (a3-1), R ¹ , R ¹⁰ and b are as defined above.

Structural unit A3 is incorporated into the resin by copolymerizing an unsaturated compound represented by the following formula (a-III) with a monomer that provides another structural unit.
Structural unit A3 may be present in the resin in block form or randomly. It is preferable that the structural unit A3 is randomly present in the resin because the structural unit A1 and the structural unit A2 are easily distributed uniformly in the resin.

As the unsaturated compound represented by the formula (a-III), a (meth)acrylic acid ester represented by the following formula (a-III-1) is preferable, and a (a-III-1a) represented by the following formula (Meth)acrylic acid esters are more preferred. In Formula (a-III), Formula (a-III-1), and Formula (a-III-1a), R ¹ , R ⁵ , R ⁶ , R ¹⁰ and b are as defined above.

Preferable specific examples of the unsaturated compound that provides the structural unit A3 include acrylic acid (1,1'-biphenyl-4-yl) ester, methacrylic acid (1,1'-biphenyl-4-yl) ester, acrylic acid (1,1′-biphenyl-3-yl) ester, (1,1′-biphenyl-3-yl) methacrylic acid ester, 4-vinyl-1,1′-biphenyl, and 3-vinyl-1,1′ - biphenyl.
Among these, acrylic acid (1,1′-biphenyl-4-yl) ester and methacrylic acid (1,1′-biphenyl-4-yl) ester are preferred.

The amount of structural unit A3 in the resin is not particularly limited as long as the object of the present invention is not impaired. The amount of the structural unit A3 in the resin is preferably 30 mol% or more and 50 mol% or less, preferably 35 mol%, based on the total structural units of the resin, because it is easy to achieve both good curability and a high refractive index of the cured product. 50 mol % or less is more preferable, and 40 mol % or more and 50 mol % or less is particularly preferable.

<Other structural units>
The resin may contain structural units other than the structural unit A1, the structural unit A2, and the structural unit A3 as long as the object of the present invention is not impaired.

Other structural units include, for example, structural units derived from (meth)acrylic acid esters. Those containing structural units can be used. (Meth)acrylic acid is acrylic acid or methacrylic acid. The (meth)acrylic acid ester is represented by the following formula (a-4-1) and is not particularly limited as long as it does not interfere with the object of the present invention.

In formula (a-IV) above, R ^a1 is a hydrogen atom or a methyl group. R ^a11 is an organic group having no active hydrogen-containing group capable of reacting with the isocyanate group generated from the blocked isocyanate group in the structural unit A1.
Groups containing active hydrogen include, for example, a hydroxyl group, a mercapto group, an amino group, and a carboxy group. This organic group may contain a bond or substituent other than a hydrocarbon group such as a heteroatom in the organic group. Moreover, this organic group may be linear, branched, or cyclic.

Substituents other than hydrocarbon groups in the organic group of R ^a11 are not particularly limited as long as the effects of the present invention are not impaired, and include halogen atoms, alkylthio groups, arylthio groups, cyano groups, silyl groups, alkoxy groups, and alkoxy groups. carbonyl group, nitro group, nitroso group, acyl group, acyloxy group, alkoxyalkyl group, alkylthioalkyl group, aryloxyalkyl group, arylthioalkyl group, N,N-disubstituted amino group (-NRR': R and R' each independently represent a hydrocarbon group). A hydrogen atom contained in the above substituent may be substituted with a hydrocarbon group. Further, the hydrocarbon group contained in the substituent may be linear, branched, or cyclic.

R ^a11 is preferably an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and these groups may be substituted with a halogen atom, an alkyl group, or a heterocyclic group. Moreover, when these groups contain an alkylene moiety, the alkylene moiety may be interrupted by an ether bond, a thioether bond, or an ester bond.

When the alkyl group is linear or branched, the number of carbon atoms is preferably 1 or more and 20 or less, more preferably 1 or more and 15 or less, and particularly preferably 1 or more and 10 or less. Examples of suitable alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec -pentyl group, tert-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, isooctyl group, sec-octyl group, tert-octyl group, n-nonyl group, isononyl group, n-decyl group, and an isodecyl group.

When R ^a11 is an alicyclic group or a group containing an alicyclic group, suitable alicyclic groups include monocyclic alicyclic groups such as cyclopentyl and cyclohexyl groups, adamantyl groups, norbornyl polycyclic alicyclic groups such as radicals, isobornyl groups, tricyclononyl groups, tricyclodecyl groups, and tetracyclododecyl groups.

Examples of monomers other than the above (meth)acrylic acid esters that provide other structural units include allyl compounds, vinyl ethers, vinyl esters, styrenes, and the like. These monomers can be used alone or in combination of two or more.

Allyl compounds include allyl esters such as allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, and allyl lactate; mentioned.

Vinyl ethers include hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, diethylene glycol vinyl ether, Alkyl vinyl ethers such as dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether; vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether , vinyl aryl ethers such as vinyl anthranyl ether;

Vinyl esters include vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, vinyl phenyl Acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl benzoate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate and the like.

Styrenes include styrene; methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, butylstyrene, hexylstyrene, cyclohexylstyrene, decylstyrene, benzylstyrene, chloromethylstyrene, trifluoromethylstyrene, ethoxy alkylstyrenes such as methylstyrene and acetoxymethylstyrene; alkoxystyrenes such as methoxystyrene, 4-methoxy-3-methylstyrene and dimethoxystyrene; chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, Halostyrenes such as dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene;

When the resin does not contain structural units other than the structural unit A1, structural unit A2, and structural unit A3 described above, the total amount of structural unit A1, structural unit A2, and structural unit A3 in the resin is 80 mol % or more is preferable, 90 mol % or more is more preferable, and 95 mol % or more is particularly preferable with respect to the structural unit.
The resin does not contain other structural units and consists only of the structural units A1, A2, and A3, since the cured product has a high refractive index and good curability. preferable.

<Resin manufacturing method>
The method for producing the resin described above is not particularly limited. In general, after mixing predetermined amounts of monomers that provide the structural units A1, A2, and A3 described above and, if necessary, monomers that provide other structural units, respectively, A resin can be obtained by performing polymerization in a solvent in the presence of a polymerization initiator in a temperature range of, for example, 50° C. or higher and 120° C. or lower. The resin is often obtained as a solution in an organic solvent, but the resin obtained as a solution can be blended as it is in the curable composition described later, or can be used as it is as the curable composition.

The weight average molecular weight of the resin obtained by the above method is preferably 30,000 or more, more preferably 35,000 or more and 100,000 or less, and particularly preferably 40,000 or more and 80,000 or less. A weight average molecular weight is a molecular weight of polystyrene conversion measured by GPC. When the weight average molecular weight of the resin is large to some extent, it is easy to form a cured product excellent in solvent resistance and thermal decomposition resistance.

The resin solution obtained as described above may be mixed with a poor solvent such as hexane, diethyl ether, methanol or water to precipitate the resin, and the precipitated resin may be recovered and used. The precipitated resin is washed after filtration, and then preferably dried under normal pressure or reduced pressure at a temperature that does not decompose the blocked isocyanate group in the structural unit A1. In this manner, the solid resin in powder form can be recovered. The powdered resin may be used as it is, or may be used by blending with a curable composition described below.

<<Curable composition>>
The curable composition contains the aforementioned resin and solvent. The type of solvent is not particularly limited as long as it does not impair the object of the present invention. The curable composition may contain a combination of two or more solvents.

Even if the solvent remains when the resin is cured, the isocyanate groups generated from the blocked isocyanate groups in the structural unit A1 do not react with the solvent. It is preferred not to have groups containing.
Groups containing active hydrogen include, for example, a hydroxyl group, a mercapto group, an amino group, and a carboxy group.
Since the solvent can be removed, for example, under reduced pressure at a temperature at which the curing of the resin does not proceed, a solvent having a group containing active hydrogen cannot necessarily be used.

Suitable examples of solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether. Monoalkyl ethers of glycols such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, and propylene glycol monobutyl ether acetate monoalkyl ether acetates of glycols; aromatic solvents such as toluene and xylene; ketones such as acetone, methyl ethyl ketone, 2-heptanone, cyclopentanone, and cyclohexanone; ethyl acetate, butyl acetate, ethyl ethoxy acetate, ethyl hydroxyacetate , 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxypropionic acid and esters such as methyl, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethyl lactate, butyl lactate, and γ-butyrolactone.

Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 2-heptanone, cyclopentanone, cyclohexanone, ethyl lactate, and butyl lactate are preferred, and propylene glycol monomethyl ether acetate, 2-heptanone, cyclopentanone, and cyclohexanone are more preferred.

The amount of the solvent to be used in the curable composition is not particularly limited, and is appropriately determined according to the application of the curable composition, taking viscosity and the like into consideration.
The amount of solvent used is preferably set so that the solid content concentration in the curable composition is 5% by mass or more, more preferably 8% by mass or more, and 10% by mass or more. It is more preferable to set The amount of solvent used is preferably set so that the solid content concentration in the curable composition is 50% by mass or less, more preferably 45% by mass or less, and 40% by mass or less. It is more preferable to set such that

The resin composition may further contain various additives as long as the object of the present invention is not impaired. Examples of additives include cross-linking agents, ultraviolet absorbers, sensitizers, plasticizers, antioxidants, light stabilizers, adhesion aids, and fillers (for example, zirconium oxide fine particles for increasing the refractive index). filler) and the like.

≪Curified product≫
A cured product is formed by molding the above resin into a desired shape and then heating the molded product. Such a cured product contains the structural unit A3 derived from the above resin, and thus has a high refractive index.
The refractive index of the cured product is preferably 1.55 or higher, more preferably 1.56 or higher, and more preferably 1.58 or higher. Although the upper limit of the refractive index is not particularly limited, it is, for example, 1.70 or less.

≪Method for producing cured product≫
A method for producing a cured product of the above resin will be described below.
The method for producing the cured product is
A molding step of molding the resin into a predetermined shape;
A curing step of curing the molded resin by heating;
including.

In the molding process, the shape of the resin after molding and the molding method of the resin are not particularly limited.
Examples of the method of molding the resin include, for example, a method of applying a composition containing a solvent and a resin onto a substrate and then removing the solvent from the coating film, and a method of applying a composition containing a solvent and a resin onto the substrate. A method of removing the solvent after filling the liquid, and a method of removing the solvent from the composition in the mold after filling the mold having a recess of a predetermined shape with the liquid of the composition containing the solvent and the resin. etc.

The method of applying the composition onto the substrate is not particularly limited. For example, using a contact transfer type coating device such as a roll coater, a reverse coater, a bar coater, a slit coater, or a non-contact type coating device such as a spinner (rotary coating device) or a curtain flow coater, the composition containing the above resin can be coated. A coating film can be formed by coating a substance on a base material so as to have a desired film thickness.

After molding a composition containing a solvent and a resin by the above method, the resin molded into a desired shape by appropriately heat-treating (pre-baking (post-apply baking (PAB)) treatment) to remove the solvent. is obtained.
The pre-baking temperature is appropriately selected in consideration of the boiling point of the solvent and the like. The pre-bake may be done at a low temperature under reduced pressure to prevent the resin from curing before the solvent is fully removed.

The pre-baking method is not particularly limited, and for example, (i) using a hot plate, the temperature is 80° C. or higher and 120° C. or lower (preferably 85° C. or higher and 100° C. or lower, more preferably 85° C. or higher and 95° C. or lower) at a temperature of 60° C. (ii) drying at room temperature for several hours or more and several days or less; (iii) drying in a hot air heater or infrared heater for several tens of minutes or more and several hours or less. or a method in which the substrate is placed and the solvent is removed.

By heating (post-baking) the resin formed as described above, a cured product of the resin is formed. The curing temperature is not particularly limited as long as the curing of the resin proceeds satisfactorily and the cured product is not thermally denatured or thermally decomposed.
The upper limit of the curing temperature is, for example, preferably 250° C. or lower, more preferably 230° C. or lower. The lower limit of the curing temperature is preferably 120°C or higher, more preferably 130°C or higher.
In addition, the resin of this embodiment can be cured at a low temperature.

By the above method, a cured product of the above resin is produced.

<<Manufacturing method of microlens>>
A method of manufacturing a microlens using the above resin will be described below.
The manufacturing method of the microlens is
a lens material layer forming step of forming a lens material layer by heating and cross-linking the resin layer obtained by applying a composition containing the above resin onto a substrate;
a lens pattern forming step of forming a lens pattern by forming a resist pattern on the lens material layer and then reflowing the resist pattern by heating to form a lens pattern;
a shape transfer step of dry-etching the lens material layer and the lens pattern using the lens pattern as a mask to transfer the shape of the lens pattern to the lens material layer;
including.

Substrates such as image elements including photodiodes (organic photodiodes, inorganic photodiodes, etc.), silicon wafers provided with color filter layers, etc., and substrates such as silicon wafers further provided with antireflection films in some cases. is mentioned.

A composition containing the above resin is typically a curable composition containing the above resin and a solvent. The method of applying the composition onto the substrate is not particularly limited. Specific examples of the method for applying the composition onto the substrate include the method described above for the method for producing the cured product.
The resin layer can be formed by appropriately heat-treating the formed coating film (pre-baking (post-apply baking (PAB)) treatment) to remove the solvent in the coating film.
The specific pre-baking method is also the same as the method for producing the cured product.

The upper limit of the curing temperature in the lens material layer forming step is, for example, preferably 250° C. or lower, and preferably 230° C. or lower. The lower limit of the curing temperature is preferably 120°C or higher, more preferably 130°C or higher.
From the viewpoint of process construction when using an organic photodiode, the heating temperature in the lens material layer forming step can be, for example, a curing condition of 180° C. or less, and a curing condition of 150° C. or less.

The film thickness of the lens material layer to be formed is preferably in the range of 100 nm to 4.0 μm, more preferably 400 nm to 2.0 μm.

The reflow heating conditions in the lens pattern forming process vary depending on the type and mixing ratio of each component in the composition used for forming the resist pattern, the film thickness of the resist pattern, etc., but the heating temperature is, for example, 60° C. to 150° C. or less (preferably 70° C. or higher and 140° C. or lower), and the heating time is, for example, about 0.5 minutes or longer and 60 minutes or shorter (preferably 1 minute or longer and 50 minutes or shorter).
The thickness of the resist pattern is preferably 100 nm or more and 4.0 μm or less, more preferably 400 nm or more and 2.0 μm or less.

Dry etching in the shape transfer step is not particularly limited, and examples thereof include dry etching using plasma ₍ oxygen, argon, CF4, etc.), corona discharge, and the like.

Through the steps described above, by using the above resin, it is possible to form a microlens having a high refractive index and little dimensional change and decrease in transparency when used in a high-temperature environment. Therefore, the microlenses formed by the above method are suitable for various uses.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
100 parts by mass of a monomer mixture consisting of 35 mol% of the methacrylic acid ester (M1) of the following formula, 35 mol% of the methacrylic acid ester (M2) of the following formula, and 30 mol% of the methacrylic acid ester (M3) of the following formula, It was mixed with 100 parts by mass of propylene glycol monomethyl ether in a flask and dissolved. The flask was heated in an oil bath until the internal temperature reached 75° C., and then a propylene glycol monomethyl ether solution containing 5 parts by mass of 2,2′-azobisisobutyronitrile was gradually dropped into the flask. After the completion of dropping, the mixture was reacted for 20 hours while maintaining the temperature.

As a result of the polymerization, a resin 1 having a structural unit represented by the following formula was obtained. In the formulas below, the numerical values in the lower right of the parentheses mean the content of each structural unit in the resin. The polystyrene-equivalent weight average molecular weight of the obtained resin 1 measured by GPC was 50,000.

[Examples 2 to 5]
A resin was obtained in the same manner as in Example 1, except that the monomer composition was changed to the composition shown in Table 1 below. The resins obtained in Examples 2 to 5 are referred to as resins 2 to 5, respectively.
The weight average molecular weights of Resins 2 to 5 were all 50,000, the same as Resin 1 obtained in Example 1.

[Examples 6 to 10 and Comparative Example 1]
In Examples 6 to 10, 99.94 parts by weight of a resin of the type shown in Table 2 and 0.06 parts by weight of a surfactant (PolyFox PF-656 (manufactured by Omnova)) were mixed in propylene glycol monomethyl ether acetate. to give a solid concentration of 15% by mass to obtain a curable composition.
In Comparative Example 1, Comparative Resin 1 (weight average molecular weight: 50,000) having the following structure was used. In the formulas below, the numerical values in the lower right of the parentheses mean the content of each structural unit in the resin.

The resulting curable composition was coated on a silicon substrate to form a cured film having a thickness of 1 μm to form a coating film. The formed coating film was pre-baked at 90° C. for 90 seconds and post-baked at 150° C. for 5 minutes to obtain a cured film. The film thickness of the obtained cured film is defined as T1.
Then, the obtained cured film was immersed in acetone at room temperature for 10 minutes, and the film thickness of the cured film after immersion was measured. The film thickness of the cured film after immersion is defined as T2.
Based on the T1 and T2 measurement results, the following formula:
Remaining film rate (%) = T2/T1 x 100
The remaining film ratio was calculated by Curability was evaluated according to the following criteria based on the calculated residual film ratio. Table 2 shows the results.
(Curability evaluation criteria)
◎: Remaining film rate is 95% or more ○: Remaining film rate is 90% or more and less than 95% ×: Remaining film rate is less than 90%

According to Table 2, in Examples 6 to 10 using the resins 1 to 5 containing the structural unit A1, the structural unit A2, and the structural unit A3, the coating film was formed to the extent that the residual film rate was 90% or more. It can be seen that it can be cured well.
On the other hand, in Comparative Example 1, in which Comparative Resin 1 containing a structural unit derived from glycidyl methacrylate was used instead of the structural unit A1, the residual film rate of the formed cured film was less than 90%, which was as high as in the Examples. hardening did not proceed.

[Example 11, Comparative Example 2, and Comparative Example 3]
In Example 11, a curable composition containing Resin 1 used in Example 9 was used. In Comparative Example 2, the curable composition used in Comparative Example 1 was used. In Comparative Example 3, 100 parts by mass of Comparative Resin 2 (weight average molecular weight: 50,000) having the following structure and 1 part by mass of a thermal acid generator were dissolved in propylene glycol monomethyl ether acetate so that the solid content concentration was 15% by mass. The curable composition thus obtained was used. The thermal acid generator used here was K-PURE (registered trademark) CXC-1821 manufactured by King Industries.

The curable composition was coated on a silicon substrate or a color filter (CF) containing a basic amine component to form a coating film with a film thickness sufficient to form a cured film having a film thickness of 1 μm. The formed coating film was pre-baked at 90° C. for 90 seconds and post-baked at 150° C. for 5 minutes to obtain a cured film. The film thickness of the obtained cured film is defined as T1.
Then, the obtained cured film was immersed in acetone at room temperature for 10 minutes, and the film thickness of the cured film after immersion was measured. The film thickness of the cured film after immersion is defined as T2.
Based on the T1 and T2 measurement results, the following formula:
Remaining film rate (%) = T2/T1 x 100
The remaining film ratio was calculated by Table 3 shows the calculated residual film ratio values.

According to Table 3, in Example 11 using resins 1 to 1 containing the structural unit A1, structural unit A2, and structural unit A3 described above, even on a Si substrate or on CF in a basic atmosphere , the coating film can be satisfactorily cured to such an extent that the same level of residual film ratio is exhibited.
On the other hand, in Comparative Example 2, in which Comparative Resin 1 containing a structural unit derived from glycidyl methacrylate was used instead of the structural unit A1, the residual film rate of the formed cured film was 90% on both the Si substrate and the CF. was less than that of the examples, and curing did not progress as much as in the examples.
In addition, in Comparative Example 3 using Comparative Resin 2 containing a structural unit derived from glycidyl methacrylate, the use of the thermal acid generator allowed curing to progress favorably on the Si substrate. However, there was a large difference in the residual film rate of the cured film between the curing on the Si substrate and the curing on the CF in the basic atmosphere.

[Example 12 and Comparative Examples 4 to 6]
In Example 12 and Comparative Examples 4 to 6, thermal stability was evaluated with respect to the film thickness and light transmittance of the cured film.
In Example 12, as in Example 11, a cured film formed on a Si substrate was used. In Comparative Example 4, as in Comparative Example 2, a cured film formed on a Si substrate was used. In Comparative Example 5, similarly to Comparative Example 3, a cured film formed on a Si substrate was used.
In Comparative Example 6, a curable composition obtained by dissolving 100 parts by mass of Comparative Resin 3 (weight average molecular weight of 10,000) having the following structure in propylene glycol monomethyl ether acetate to a solid content concentration of 18% by mass was used. A cured film was formed on a Si substrate in the same manner as in Example 11. The film thickness T1 of the cured film immediately after formation was measured.
In addition, the transmittance LT1 of light having a wavelength of 400 nm was measured for the cured film immediately after the formation.

After placing the formed cured film in a constant temperature bath at 150 ° C., the cured film was taken out after 200 hours, 500 hours, 1000 hours, and 2000 hours, and the film thickness T3 and the wavelength 400 nm were measured. The light transmittance LT2 was measured. Based on the measurement results at each time, the following formula:
Film thickness reduction rate (%) = T3/T1 x 100
Light transmittance reduction rate (%) = LT2/LT1 x 100
, the film thickness reduction rate and the light transmittance reduction rate at each time were obtained. Table 4 shows the film thickness reduction rate and the light transmittance reduction rate at each time.

According to Table 4, in Example 12 using the resin 1 containing the structural unit A1, the structural unit A2, and the structural unit A3, even if the cured film was held at 150 ° C. for 2000 hours, the film thickness and the light transmission It can be seen that the rate does not decrease.
On the other hand, in Comparative Examples 4 to 6, in which Comparative Resins 1, 2, and 3 containing a structural unit derived from glycidyl methacrylate were used instead of the structural unit A1, the formed cured film had a temperature of 150°C. It was found that the film thickness and the light transmittance decreased remarkably with the passage of time.

[Examples 13 to 15 and Comparative Example 7]
Resin 6 and Comparative Resin 4 were obtained in the same manner as in Example 1, except that the monomer composition was changed to the composition shown in Table 5 below. In addition, M4 described in Table 5 is styrene.
In Examples 13 to 15 and Comparative Example 7, 99.94 parts by weight of the resin of the type shown in Table 5 and 0.06 parts by weight of a surfactant (PolyFox PF-656 (manufactured by Omnova)) were mixed with propylene. A curable composition was obtained by dissolving in glycol monomethyl ether acetate so as to give a solid content concentration of 15% by mass.
Using each curable composition, a cured film having a thickness of 1 μm was formed in the same manner as in Example 6, and the refractive index of the formed cured film was measured. Table 5 shows the measurement results of the refractive index.

According to Table 5, in Examples 13 to 15 using the resin 1 containing the structural unit A1, the structural unit A2, and the structural unit A3 described above, it can be seen that a cured film having a refractive index of 1.56 or more can be formed. .
On the other hand, in Comparative Example 7 using Comparative Resin 4 containing a structural unit derived from styrene containing only one benzene ring instead of the structural unit A3, only a cured film having a refractive index of about 1.54 could be formed. .

Claims (12)

a resin containing a structural unit represented by the following formula (a1), a structural unit represented by the following formula (a2), and a structural unit represented by the following formula (a3);
a solvent;
A structural unit represented by the following formula (a3) is a structural unit represented by the following formula (a3-1) ,
The total amount of structural units represented by the following formula (a1), structural units represented by the following formula (a2), and structural units represented by the following formula (a3) in the resin is the total amount of structural units in the resin is 60 mol% or more with respect to
The curable composition , wherein the amount of the structural unit represented by the following formula (a1) in the resin is 15 mol % or more and 45 mol % or less with respect to all structural units of the resin .

(In formulas (a1), (a2), and (a3), R ¹ is each independently a hydrogen atom or a methyl group, and R ² is a single bond or an alkylene group having 1 to 5 carbon atoms. , R ³ is a blocked isocyanate group, R ⁴ is a divalent hydrocarbon group, R ⁵ is a single bond or a divalent linking group, R ⁶ is two or more benzene rings is an organic group containing

(In formula (a3-1), R ¹ is the same as in formula (a3) above, R ¹⁰ is each independently a halogen atom or an organic group having 1 to 6 carbon atoms, and b is It is an integer from 0 to 4.) As the structural unit represented by the formula (a1), a structural unit represented by the following formula (a1-1), a structural unit represented by the following formula (a1-2), and a structural unit represented by the following formula (1-3) 2. The curable composition of claim 1, comprising at least one structural unit selected from the group consisting of structural units shown.

(In formula (a1-1), formula (a1-2) and formula (a1-3), R ¹ and R ² are the same as in formula (a1) above, and R ⁷ is each independently a carbon atom 1 to 12 organic groups, R ⁸ is each independently a halogen atom or an organic group having 1 to 6 carbon atoms, and R ⁹ is each independently an organic group having 1 to 6 carbon atoms. Yes, and a is an integer from 0 to 3.) 3. The curable composition according to claim 1 or 2, wherein said ^R4 is a divalent chain aliphatic hydrocarbon group. The curable composition according to any one of claims 1 to 3 , wherein the ratio of the structural unit represented by the formula (a3) in all structural units of the resin is 30 mol% or more and 50 mol% or less. thing. Claims 1 to 1, wherein the ratio of the number of moles of the structural unit represented by the formula (a1) to the number of moles of the structural unit represented by the formula (a2) is 80/100 or more and 100/80 or less. 5. The curable composition according to any one of 4 . The curable composition according to any one of claims 1 to 5 , wherein the resin has a weight average molecular weight of 30,000 or more. A cured product obtained by curing the curable composition according to any one of claims 1 to 6 . The cured product according to claim 7 , which has a refractive index of 1.55 or more. A molding step of molding the curable composition according to any one of claims 1 to 6 into a predetermined shape;
A curing step of curing the molded curable composition by heating;
A method for producing a cured product containing. The method for producing a cured product according to claim 9 , wherein the heating temperature in the curing step is 180°C or less. A lens material layer forming step of forming a lens material layer by heating and cross-linking a resin layer obtained by applying the curable composition according to any one of claims 1 to 6 on a substrate;
a lens pattern forming step of forming a lens pattern by forming a resist pattern on the lens material layer and then reflowing the resist pattern by heating to form a lens pattern;
a shape transfer step of dry-etching the lens material layer and the lens pattern using the lens pattern as a mask to transfer the shape of the lens pattern to the lens material layer;
A method of manufacturing a microlens, comprising: 12. The method of manufacturing a microlens according to claim 11 , wherein the heating temperature in said lens material layer forming step is 180[deg.] C. or less.