Radical polymerizable polymer and photosensitive composition thereof

Abstract

To provide a radical-polymerizable polymer which enables formation of a coating film excellent in heat resistance, transparency and coating property, and a photosensitive resin composition containing the polymer.SOLUTION: A radical-polymerizable polymer is a polymer having a structural unit derived from an unsaturated monomer having an acid group, a structural unit derived from an unsaturated monomer having a hydroxyl group, and a main chain ring structure of a specific structure, the polymer having a polymerizable double bond in a side chain, wherein a double bond equivalent of the polymer is 330-1,600 (g / mol) and an acid value thereof is 50-150 (mgKOH / g). A content ratio of a structural unit derived from a maleimide-based monomer is preferably 5 mass% or less with respect to 100 mass% of the total structural units of the radical-polymerizable polymer. A photosensitive resin composition contains the radical-polymerizable polymer, a polyfunctional monomer, a photopolymerization initiator, inorganic fine particles, and a solvent.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a radical polymerizable polymer and a photosensitive composition thereof. More specifically, the present invention relates to a radical polymerizable polymer and a photosensitive resin composition containing, as essential components, a radical polymerizable polymer, a polyfunctional monomer, a photopolymerization initiator, inorganic fine particles and a solvent. [Background technology]

[0002] Conventionally, as polymers having radical polymerization properties excellent in heat resistance and transparency, for example, Patent Document 1 proposes a polymer obtained by polymerizing a monomer component containing maleimide, Patent Document 2 proposes a polymer obtained by polymerizing a compound having a specific structure that is an ether dimer of 2-(hydroxyalkyl)acrylic acid ester, and Patent Document 3 proposes a radical polymerization polymer having a constitutional unit derived from a maleimide monomer, a constitutional unit derived from a monomer having a carboxyl group or an epoxy group, and a constitutional unit derived from an α-(unsaturated alkoxyalkyl)acrylate monomer. Patent Document 4 proposes a polymer obtained by polymerizing an N-substituted maleimide, a carboxyl monomer, and a hydroxy monomer.

[0003] In a resin composition containing a maleimide-derived polymer (maleimide-based polymer), since the maleimide-based polymer contains nitrogen atoms, the polymer is colored yellow to yellowish brown, and the transparency of the cured film is insufficient. This transparency problem is particularly noticeable when the cured film is thick, and furthermore, the film may become more colored when subjected to heat treatment. On the other hand, a resin composition containing a polymer obtained by polymerizing a compound having a specific structure, which is an ether dimer of 2-(hydroxyalkyl)acrylic acid ester, together with a curing component, can form a coating film that is extremely excellent in both heat resistance and transparency, but there are cases where improvements are required because the demand for the coloring level after heat treatment is increasing year by year. [Prior art documents] [Patent documents]

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above situation, an object of the present invention is to provide a radically polymerizable polymer capable of forming a coating film excellent in heat resistance (particularly thermal decomposition resistance), transparency, and coatability, and a photosensitive resin composition containing the polymer.

Means for Solving the Problems

[0006] As a result of various studies on the polymer, the present inventors have found that a polymer having a polymerizable double bond in a side chain containing a structural unit derived from an unsaturated monomer having an acid group, a structural unit derived from an unsaturated monomer having a hydroxyl group, and a structural unit represented by the following formula (1), and having a double bond equivalent of the polymer of 330 to 1600 (g / mol) and an acid value of 50 to 150 (mgKOH / g) can solve the problems.

[0007]

Chemical Formula

[0008] (R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.) Preferably, with respect to 100% by mass of all the structural units of the radically polymerizable polymer, the content ratio of the structural unit derived from the N-substituted maleimide monomer is 5% by mass or less.

[0009] More preferably, the content of the structural units derived from the tertiary carbon-containing (meth)acrylate monomer is 5% by mass or less relative to 100% by mass of all the structural units of the radically polymerizable polymer. The present invention also relates to a photosensitive resin composition comprising the above radical polymerizable polymer, a polyfunctional monomer, a photopolymerization initiator, inorganic fine particles and a solvent. Effect of the Invention

[0010] The radical polymerizable polymer and photosensitive resin composition of the present invention can form a coating film having excellent heat resistance (particularly thermal decomposition resistance), transparency and coatability, and can be suitably used in applications such as resist materials, various coating agents, paints, etc. Furthermore, according to the present invention, a cured film having high hardness can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention. In this specification, "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid", and "(meth)acrylate" means "acrylate and / or methacrylate". In this specification, the numerical range "Min to Max" means a range equal to or greater than the minimum value Min and equal to or less than the maximum value Max. Furthermore, when the upper and lower limit values ​​are described as suitable numerical values ​​in stages, a numerical range obtained by appropriately combining the upper and lower limit values ​​described separately is also a suitable numerical range. As described above, the polymer of the present invention is a polymer having a polymerizable double bond in a side chain including a constituent unit derived from an unsaturated monomer having an acid group, a constituent unit derived from an unsaturated monomer having a hydroxyl group, and a constituent unit represented by the following formula (1), and the polymer is a radically polymerizable polymer having a double bond equivalent of 330 to 1600 (g / mol) and an acid value of 50 to 150 (mgKOH / g).

[0012] [ka]

[0013] (R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.) The structural unit derived from the unsaturated monomer corresponds to a structure (structural unit) in which the polymerizable double bond of each unsaturated monomer is opened by a polymerization reaction. The structure in which the polymerizable double bond is opened is, for example, a structure in which the double bond between carbon atoms (C=C) becomes a single bond (-CC-). The acid group contained in the unsaturated monomer having an acid group is not particularly limited as long as it is a functional group that shows acidity in water, but a carboxyl group is preferable. A preferred form includes a polymer obtained by copolymerizing (a) an unsaturated monomer having a carboxyl group, (b) an unsaturated monomer having a hydroxyl group, and (c) an α-(unsaturated alkoxyalkyl)acrylate monomer as essential components. More preferred examples include polymers in which the content of (meth)acrylate having a carboxyl group is 0.5-50% by mass, the content of (meth)acrylate having a hydroxyl group is 0.5-50% by mass, and the content of α-(unsaturated alkoxyalkyl)acrylate monomer is 0.5-60% by mass, based on 100% by mass of the total of all monomer components constituting the polymer. Note that, as the polymer having a structural unit derived from the unsaturated monomer having an acid group, a structure in which a structural unit having an acid group is formed by polymerizing an unsaturated monomer having a hydroxyl group and then reacting it with an acid anhydride is also included in the polymer of the present invention.

[0014] The use of the polymer of the present invention is not particularly limited, but it can be suitably used in various applications such as printing plate making, protective films for color filters, and liquid crystal display panel manufacturing such as color filters and black matrices. In particular, the obtained cured film has high hardness and high transparency, so it is very useful as a protective film or insulating film in various display devices. The display device is not particularly limited, but for example, a liquid crystal display device, a solid-state imaging device, a touch panel display device, etc. are suitable. As the touch panel display device, a capacitance type display device is particularly preferred. The radical polymerizable polymer of the present invention is a photosensitive alkali-soluble resin and shows good developability. As a preferred acid group contained in the alkali-soluble resin, the unsaturated monomer having a carboxyl group (preferably (meth)acrylate) includes, for example, (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, etc., among which, (meth)acrylic acid is particularly preferred. The content ratio of the unsaturated monomer containing a carboxyl group is preferably in the range of 0.5 to 50 mass% in the total monomer components, more preferably 2 to 50 mass%, and even more preferably 5 to 45 mass%. Within the above range, the solubility in an alkaline substance is sufficient, and the viscosity of the obtained polymer is not too high, resulting in good handleability. The proportion of the structural units derived from unsaturated monomers having an acid group in all the structural units is preferably within the above-mentioned range (0.5 to 50% by mass).

[0015] As the unsaturated monomer having a hydroxyl group, which is an essential component of the polymer of the present invention, an unsaturated monomer having a primary hydroxyl group or a secondary hydroxyl group is preferable. Among them, a (meth)acrylate having a primary hydroxyl group or a secondary hydroxyl group is preferable. For example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, mono(poly)ethylene glycol (meth)acrylate, mono(poly)propylene glycol (meth)acrylate, etc. are mentioned, among which 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate are particularly preferable. The content ratio of the unsaturated monomer having a hydroxyl group is preferably in the range of 0.5 to 50 mass% in the total monomer components, more preferably 2 to 40 mass%, and further preferably 5 to 30 mass%. Within the above range, the heat resistance is sufficient, the solubility is high, and the viscosity of the polymer is not too high, resulting in good handleability. The proportion of the structural units derived from unsaturated monomers having a hydroxyl group in all the structural units is preferably within the above-mentioned range (0.5 to 50% by mass).

[0016] The constitutional unit represented by the above formula (1), which is an essential unit of the polymer of the present invention, is a constitutional unit derived from an α-(unsaturated alkoxyalkyl)acrylate monomer, and is, for example, Formula (2):

[0017] [ka]

[0018] (R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.) It is preferable to form the monomer by polymerizing a monomer represented by the following formula (2): This is because the monomer represented by formula (2) is polymerized to produce the constitutional unit represented by formula (1) in a high proportion, and is unlikely to undergo abnormally high molecular weight or gelation.

[0019] R in the monomer represented by formula (2) represents a hydrogen atom or an organic group having 1 to 30 carbon atoms, and may be appropriately selected according to the purpose and use. Specific examples of R are the same as R in formula (1), and include, for example, a hydrogen atom; chain saturated alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-amyl, s-amyl, t-amyl, n-hexyl, s-hexyl, n-heptyl, n-octyl, s-octyl, t-octyl, 2-ethylhexyl, capryl, nonyl, decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, nonadecyl, eicosyl, seryl, and melissyl. Hydrocarbon groups; alkoxy-substituted saturated chain hydrocarbon groups in which some of the hydrogen atoms of a chain saturated hydrocarbon group have been replaced with alkoxy groups, such as methoxyethyl, methoxyethoxyethyl, methoxyethoxyethoxyethyl, 3-methoxybutyl, ethoxyethyl, ethoxyethoxyethyl, phenoxyethyl, and phenoxyethoxyethyl; hydroxy-substituted saturated chain hydrocarbon groups in which some of the hydrogen atoms of a chain saturated hydrocarbon group have been replaced with hydroxy groups, such as hydroxyethyl, hydroxypropyl, and hydroxybutyl; fluoroethyl, difluoroethyl, halogen-substituted linear saturated hydrocarbon groups in which some of the hydrogen atoms of linear saturated hydrocarbon groups, such as perfluoroethyl, chloroethyl, dichloroethyl, bromoethyl, and dibromoethyl, have been replaced with halogens; linear unsaturated hydrocarbon groups, such as vinyl, allyl, methallyl, crotyl, and propargyl, and linear unsaturated hydrocarbon groups in which some of the hydrogen atoms have been replaced with alkoxy groups, hydroxy groups, or halogens; alicyclic hydrocarbon groups, such as cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, tricyclodecanyl, isobornyl, adamantyl, and dicyclopentadienyl, and alicyclic hydrocarbon groups in which some of the hydrogen atoms have been replaced with alkoxy groups, hydroxy groups, or halogens; aromatic hydrocarbon groups, such as phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, 4-t-butylphenyl, benzyl, diphenylmethyl, diphenylethyl, triphenylmethyl, cinnamyl, naphthyl, and anthranyl, and aromatic hydrocarbon groups in which some of the hydrogen atoms have been replaced with alkoxy groups, hydroxy groups, or halogens.In addition, a substituent may be further bonded to these organic groups. R in the formulae (1) and (2) may be the same or different and may be two or more types.

[0020] Examples of monomers represented by formula (2) suitable as α-(unsaturated alkoxyalkyl)acrylate monomers by compound name include α-allyloxymethylacrylic acid, methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, i-propyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, s-butyl α-allyloxymethylacrylate, t-butyl α-allyloxymethylacrylate, n-amino α-allyloxymethylacrylate, α-allyloxymethylacrylic acid s-amyl, α-allyloxymethylacrylic acid t-amyl, α-allyloxymethylacrylic acid n-hexyl, α-allyloxymethylacrylic acid s-hexyl, α-allyloxymethylacrylic acid n-heptyl, α-allyloxymethylacrylic acid n-octyl, α-allyloxymethylacrylic acid s-octyl, α-allyloxymethylacrylic acid t-octyl, α-allyloxymethylacrylic acid 2-ethylhexyl, α-allyloxymethylacrylic acid capryl, α-allyloxymethylacrylic acid nonyl α-allyloxymethylacrylate, decyl α-allyloxymethylacrylate, undecyl α-allyloxymethylacrylate, lauryl α-allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, pentadecyl α-allyloxymethylacrylate, cetyl α-allyloxymethylacrylate, heptadecyl α-allyloxymethylacrylate, stearyl α-allyloxymethylacrylate, nonadecyl α-allyloxymethylacrylate, eicosyl α-allyloxymethylacrylate, α-allyloxymethylacrylate, Ceryl methylacrylate, melissyl α-allyloxymethylacrylate, methoxyethyl α-allyloxymethylacrylate, methoxyethoxyethyl α-allyloxymethylacrylate, methoxyethoxyethoxyethyl α-allyloxymethylacrylate, 3-methoxybutyl α-allyloxymethylacrylate, ethoxyethyl α-allyloxymethylacrylate, ethoxyethoxyethyl α-allyloxymethylacrylate, phenoxyethyl α-allyloxymethylacrylate, phenoxyethoxyethyl α-allyloxymethylacrylate,Hydroxyethyl α-allyloxymethylacrylate, Hydroxypropyl α-allyloxymethylacrylate, Hydroxybutyl α-allyloxymethylacrylate, Fluoroethyl α-allyloxymethylacrylate, Difluoroethyl α-allyloxymethylacrylate, Chloroethyl α-allyloxymethylacrylate, Dichloroethyl α-allyloxymethylacrylate, Bromoethyl α-allyloxymethylacrylate, Dibromoethyl α-allyloxymethylacrylate, Vinyl α-allyloxymethylacrylate, Allyl α-allyloxymethylacrylate, Methallyl α-allyloxymethylacrylate, Crotyl α-allyloxymethylacrylate, Propargyl α-allyloxymethylacrylate, Cyclopentyl α-allyloxymethylacrylate, Cyclohexyl α-allyloxymethylacrylate, 4-Methylcyclohexyl α-allyloxymethylacrylate, α-Allyloxymethylacrylate Examples of the monomers represented by formula (2) include 4-t-butylcyclohexyl acrylate, tricyclodecanyl α-allyloxymethylacrylate, isobornyl α-allyloxymethylacrylate, adamantyl α-allyloxymethylacrylate, dicyclopentadienyl α-allyloxymethylacrylate, phenyl α-allyloxymethylacrylate, methylphenyl α-allyloxymethylacrylate, dimethylphenyl α-allyloxymethylacrylate, trimethylphenyl α-allyloxymethylacrylate, 4-t-butylphenyl α-allyloxymethylacrylate, benzyl α-allyloxymethylacrylate, diphenylmethyl α-allyloxymethylacrylate, diphenylethyl α-allyloxymethylacrylate, triphenylmethyl α-allyloxymethylacrylate, cinnamyl α-allyloxymethylacrylate, naphthyl α-allyloxymethylacrylate, and anthranyl α-allyloxymethylacrylate. These monomers represented by formula (2) can be used alone or in combination of two or more. The proportion of the monomer represented by the above formula (2) relative to the total of all monomer components constituting the above polymer is not particularly limited, but is preferably 0.5 to 60 mass %, preferably 1.5 to 55 mass %, and more preferably 2 to 50 mass % of the total monomer components.

[0021] When the content is within the above range, the heat resistance and transparency are sufficient, and the polymer has a suitable viscosity and good handleability. The proportion of the structural unit of the above formula (1) in all structural units is preferably within the above range (0.5 to 60 mass%).

[0022] In addition to the monomer represented by the above formula (2) (α-(unsaturated alkoxyalkyl)acrylate monomer), the copolymer may contain a structural unit derived from at least one monomer selected from an N-substituted maleimide monomer and a dialkyl-2,2'-(oxydimethylene)diacrylate monomer (also called an ether dimer).

[0023] The above-mentioned α-(unsaturated alkoxyalkyl)acrylate monomer, N-substituted maleimide monomer, and ether dimer are monomers capable of introducing a ring structure into the main chain skeleton of a polymer. The N-substituted maleimide monomer is a monomer having a double bond-containing ring structure in the molecule, and the α-(unsaturated alkoxyalkyl)acrylate monomer and ether dimer are monomers that undergo cyclic polymerization to form a polymer having a ring structure in the main chain. Therefore, it is possible to provide a cured film having improved heat resistance, dispersibility (e.g., colorant dispersibility), hardness, etc. In particular, a polymer containing an ether dimer and / or an α-(unsaturated alkoxyalkyl)acrylate monomer unit has a ring structure in the main chain, so it has high heat resistance, and does not contain a nitrogen atom, so it has good transparency. As described above, a polymer containing a monomer unit means, for example, a polymer containing a constituent unit derived from the monomer by a polymerization reaction or crosslinking reaction of the monomer.

[0024] Examples of the N-substituted maleimide monomer include N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-t-butylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, N-naphthylmaleimide, etc., and one or more of these can be used. Among them, N-cyclohexylmaleimide, N-phenylmaleimide, and N-benzylmaleimide are preferable in terms of less coloring and excellent dispersibility, and N-benzylmaleimide is particularly suitable.

[0025] Examples of the N-benzylmaleimide include benzylmaleimide; alkyl-substituted benzylmaleimides such as p-methylbenzylmaleimide and p-butylbenzylmaleimide; phenolic hydroxyl group-substituted benzylmaleimides such as p-hydroxybenzylmaleimide; halogen-substituted benzylmaleimides such as o-chlorobenzylmaleimide, o-dichlorobenzylmaleimide, and p-dichlorobenzylmaleimide; etc.

[0026] As the dialkyl-2,2'-(oxydimethylene) diacrylate monomer, for example, from the viewpoints of less coloring, dispersibility, and easy industrial availability, it is preferable to use dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, etc.

[0027] Examples of the α-(unsaturated alkoxyalkyl)acrylate monomer include α-allyloxymethylacrylic acid, methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, i-propyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, s-butyl α-allyloxymethylacrylate, t-butyl α-allyloxymethylacrylate, n-amyl α-allyloxymethylacrylate, s-amyl α-allyloxymethylacrylate, t-amyl α-allyloxymethylacrylate, neopentyl α-allyloxymethylacrylate, n-hexyl α-allyloxymethylacrylate, s-hexyl α-allyloxymethylacrylate, n-heptyl α-allyloxymethylacrylate, n-octyl α-allyloxymethylacrylate, and s-octyl α-allyloxymethylacrylate. Preferred are chain-like saturated hydrocarbon group-containing α-(allyloxymethyl)acrylates such as α-allyloxymethylacrylate, t-octyl α-allyloxymethylacrylate, 2-ethylhexyl α-allyloxymethylacrylate, capryl α-allyloxymethylacrylate, nonyl α-allyloxymethylacrylate, decyl α-allyloxymethylacrylate, undecyl α-allyloxymethylacrylate, lauryl α-allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, pentadecyl α-allyloxymethylacrylate, cetyl α-allyloxymethylacrylate, heptadecyl α-allyloxymethylacrylate, stearyl α-allyloxymethylacrylate, nonadecyl α-allyloxymethylacrylate, eicosyl α-allyloxymethylacrylate, ceryl α-allyloxymethylacrylate, and melissyl α-allyloxymethylacrylate. In addition, alkyl-(α-methallyloxymethyl)acrylate monomers are also preferred, and among these, methyl α-allyloxymethylacrylate (also referred to as α-(allyloxymethyl)methylacrylate) is particularly preferred.

[0028] The above-mentioned α-(unsaturated alkoxyalkyl) acrylate monomer can be produced, for example, by the production method disclosed in WO 2010 / 114077.

[0029] The proportion of the ether dimer relative to the total of all monomer components constituting the polymer is not particularly limited, but is preferably 0.5 to 60 mass %, preferably 1.5 to 55 mass %, and more preferably 2 to 50 mass % of the total monomer components.

[0030] When the content is within the above range, the heat resistance and transparency are sufficient, and the viscosity of the polymer is appropriate, resulting in good handleability. The proportion of the structural units derived from the ether dimer in all structural units is preferably within the above range (0.5 to 60% by mass). The proportion of the N-substituted maleimide monomer is not particularly limited depending on the application. In consideration of adhesion, a monomer selected from N-phenylmaleimide and N-cyclohexylmaleimide may be contained in place of or in combination with the α-(unsaturated alkoxyalkyl)acrylate monomer. In consideration of both heat resistance and transparency, the proportion of the N-substituted maleimide monomer in the total monomer component is preferably 0 to 5 mass%, more preferably 0 to 3 mass%, particularly preferably 0 to 1 mass%, and most preferably substantially absent. The proportion of the structural unit derived from the N-substituted maleimide monomer in the total structural units is preferably within the above-mentioned range of 0 to 5 mass% (5 mass% or less).

[0031] In addition, the monomer components used to obtain the radically polymerizable polymer of the present invention may contain other copolymerizable monomers as necessary in addition to the essential components of the unsaturated monomer having an acid group (preferably a carboxyl group), the unsaturated monomer having a hydroxyl group, and the monomer represented by the above formula (2). Examples of the other copolymerizable monomers include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. In addition, aromatic vinyl compounds such as styrene, vinyl toluene, and α-methylstyrene may be copolymerized to the extent that the heat resistance is not affected; alkyl-substituted maleimides such as N-methylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide, maleimides having aromatic groups such as N-phenylmaleimide and N-benzylmaleimide; butadiene or substituted butadiene compounds such as butadiene and isoprene; ethylene or substituted ethylene compounds such as ethylene, propylene, vinyl chloride, and acrylonitrile; vinyl esters such as vinyl acetate; and the like. Among these, methyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate are preferred in that they have good transparency and are unlikely to impair heat resistance. These other copolymerizable monomers may be used alone or in combination of two or more.

[0032] In the present invention, since a polymer that loses weight by heating is not preferred, it is preferable that the number of structural units derived from a tertiary carbon-containing (meth)acrylate monomer, for example, t-butyl (meth)acrylate and / or t-amyl (meth)acrylate, is small. This is because heating may break the O-C bond between the oxygen atom adjacent to the (meth)acryloyl group and the tertiary carbon atom adjacent thereto. The ratio of the tertiary carbon-containing (meth)acrylate monomer is not particularly limited depending on the application, but in consideration of reducing thermal weight loss and transparency, it is preferably 0 to 5 mass % of the total monomer components, more preferably 0 to 3 mass %, particularly preferably 0 to 1 mass %, and most preferably substantially absent. The ratio of structural units derived from a tertiary carbon-containing (meth)acrylate monomer is preferably within the above-mentioned range of 0 to 5 mass % (5 mass % or less) in the total structural units. In addition, the radical polymerizable polymer of the present invention preferably further contains a polymerizable double bond in the side chain. By providing a polymerizable double bond in the side chain, it can be cured by heat or light. Therefore, when it is made into a photosensitive resin composition, the sensitivity to light is improved, it is cured with a smaller amount of light, and the mechanical strength after curing is also high. As a method for introducing a polymerizable double bond into a side chain, a method of adding at least one selected from the group consisting of an epoxy group, an oxazoline group, and a hydroxyl group and a compound containing a polymerizable unsaturated double bond can be mentioned. As the polymerizable unsaturated double bond, a double bond possessed by a (meth)acryloyl group is preferably mentioned in terms of the reactivity of the obtained polymer. The polymer before the polymerizable double bond is given to the side chain is also called a base polymer.

[0033] Specific examples of the compound containing at least one selected from the group consisting of an epoxy group, an oxazoline group, and a hydroxyl group and a polymerizable unsaturated double bond include compounds having a hydroxyl group and a double bond, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and allyl alcohol; compounds having an epoxy group and a double bond, such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and allyl glycidyl ether; compounds having an oxazoline group and a double bond, such as vinyloxazoline and isopropenyloxazoline; and the like. Preferred specific examples include compounds having an epoxy group and a carbon-carbon double bond, such as glycidyl (meth)acrylate, allyl glycidyl ether, α-ethyl glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl acrylate (e.g., "Cyclomer A400" manufactured by Daicel Chemical Industries, Ltd.), 3,4-epoxycyclohexylmethyl methacrylate (e.g., "Cyclomer M100" manufactured by Daicel Chemical Industries, Ltd.), and o-(or m-, or p-)vinylbenzyl glycidyl ether. Among these, glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate are particularly preferred, since they are highly reactive, the reaction is easily controlled, they are easily available, and they can simultaneously introduce not only a radically polymerizable double bond but also a hydroxyl group. The amount of the compound containing a polymerizable unsaturated double bond used is preferably 5 to 120% by mass, more preferably 5 to 80% by mass, and particularly preferably 5 to 60% by mass, based on the polymer (base polymer) before addition. By setting the amount within the above range, the exposure sensitivity, developability, and storage stability are improved.

[0034] The radical polymerizable polymer of the present invention may further contain an epoxy group. This allows the polymer to be cured by heat or light. To introduce an epoxy group into the polymer, for example, a monomer having an epoxy group may be polymerized as a monomer component. Examples of the monomer having an epoxy group include glycidyl (meth)acrylate and 3,4-epoxycyclohexyl (meth)acrylate. The monomer for introducing the epoxy group may be one type only or two or more types. As a method for polymerizing the monomer components, commonly used methods such as bulk polymerization, solution polymerization, and emulsion polymerization can be used, and may be appropriately selected depending on the purpose and use. Among them, solution polymerization is preferable because it is industrially advantageous and easy to adjust the structure such as molecular weight. In addition, as a polymerization mechanism of the monomer components, a polymerization method based on a mechanism such as radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization can be used, but a polymerization method based on a radical polymerization mechanism is preferable because it is industrially advantageous. The polymerization initiation method in the above polymerization reaction may be achieved by supplying the energy required for polymerization initiation to the monomer component from an active energy source such as heat, electromagnetic waves (infrared rays, ultraviolet rays, X-rays, etc.), electron beams, etc., and further using a polymerization initiator in combination can significantly reduce the energy required for polymerization initiation and is preferable because it facilitates reaction control. The molecular weight of the polymer obtained by polymerizing the above monomer components can be controlled by adjusting the amount and type of the polymerization initiator, the polymerization temperature, and the type and amount of the chain transfer agent, etc. When the monomer components are polymerized by a solution polymerization method, the solvent used for polymerization is not particularly limited as long as it is inactive in the polymerization reaction, and may be appropriately selected depending on the polymerization conditions such as the polymerization mechanism, the type and amount of the monomer used, the polymerization temperature, and the polymerization concentration. However, when a solvent is used as a diluent or the like when a photosensitive resin composition is subsequently produced, it is efficient and preferable to use a solvent containing the solvent for the solution polymerization of the monomer components.

[0035] Suitable examples of the solvent include the following compounds, and one or more of these can be used. Monoalcohols such as methanol, ethanol, isopropanol, n-butanol, and s-butanol; glycols such as ethylene glycol and propylene glycol; cyclic ethers such as tetrahydrofuran and dioxane; glycol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and 3-methoxybutanol; glycol ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol dimethyl ether, and propylene glycol diethyl ether; ethylene glycol monomethyl ether acetone esters of glycol monoethers such as ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monobutyl ether acetate, and 3-methoxybutyl acetate; alkyl esters such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl lactate, ethyl lactate, butyl lactate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl acetoacetate, and ethyl acetoacetate;Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, etc.; aliphatic hydrocarbons such as hexane, cyclohexane, octane, etc.; amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.; Among these solvents, it is more preferable to use propylene glycol monomethyl ether acetate and isopropanol in terms of the solubility and transparency of the resulting polymer and their action as a chain transfer agent.

[0036] The amount of the solvent used is preferably 50 to 1000 parts by mass, and more preferably 100 to 500 parts by mass, per 100 parts by mass of the base polymer component. When the monomer components are polymerized, as described above, a polymerization initiator that is commonly used may be added. The polymerization initiator is not particularly limited, but examples thereof include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy isopropyl carbonate, t-amyl peroxy-2-ethylhexanoate, and t-butyl peroxy-2-ethylhexanoate; and azo compounds such as 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobis(2-methylpropionate). These polymerization initiators may be used alone or in combination of two or more. The amount of the initiator used may be appropriately set depending on the combination of monomers used, reaction conditions, the molecular weight of the target polymer, and the like, and is not particularly limited. However, in order to obtain a polymer having a weight average molecular weight of several thousand to several tens of thousands without gelation, it is preferable to use an amount of 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, based on the total monomer components.

[0037] When the monomer components are polymerized, a chain transfer agent that is commonly used may be added as necessary to adjust the molecular weight. Examples of the chain transfer agent include mercaptan-based chain transfer agents such as n-dodecyl mercaptan, mercaptopropionic acid, mercaptoacetic acid, and methyl mercaptoacetate, thiol-based chain transfer agents such as 2-mercaptoethanol, thioglycolic acid, 3-mercaptopropionic acid, thiosalicylic acid, 1-thioglycerol, and 4-aminothiophenol, and α-methylstyrene dimer. However, n-dodecyl mercaptan and mercaptopropionic acid are preferable because they have a high chain transfer effect, can reduce residual monomers, and are easily available. When a chain transfer agent is used, the amount of the chain transfer agent used may be appropriately set according to the combination of monomers used, reaction conditions, and the molecular weight of the target polymer, and is not particularly limited. However, it is preferable to use 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, based on the total monomer components, in order to obtain a polymer having a weight average molecular weight of several thousand to several tens of thousands without gelation. In order to increase the transparency of the polymer of the present invention, the amount of a thiol-based chain transfer agent is preferably 1% by mass or less, more preferably 0.1% by mass or less, based on the total monomer components, and particularly preferably is substantially free of the thiol-based chain transfer agent.

[0038] The weight average molecular weight (Mw) of the polymer is not particularly limited, but is preferably 2000 to 200000, more preferably 5000 to 100000, particularly preferably 5000 to 50000, and most preferably 5000 to 20000. When the weight average molecular weight is within the above range, the viscosity is not too high, the coating property is good, and heat resistance can be expressed. The weight average molecular weight can be determined by GPC (gel permeation chromatography) method using polystyrene as a standard substance, tetrahydrofuran (THF) as an eluent, HLC-8220GPC (manufactured by Tosoh Corporation) and column TSKgel SuperHZM-N (manufactured by Tosoh Corporation). The acid value of the polymer is preferably 50 to 150 mgKOH / g, more preferably 60 to 130 mgKOH / g. It is further preferably 70 to 120 mgKOH / g. When the acid value is within the above range, the viscosity is not too high, the coating property is good, and when solubility by an alkaline substance is required, the solubility is sufficient. The acid value of the polymer can be determined, for example, by using a 0.1 N KOH aqueous solution as a titrant, measuring the acid value of the polymer solution with an automatic titrator (manufactured by Hiranuma Sangyo Co., Ltd., product name "COM-555"), and calculating the acid value per solid content from the acid value of the solution and the solid content of the solution. The solid content of the polymer solution can be determined as follows. Approximately 0.3 g of the polymer solution is weighed out in an aluminum cup, and approximately 1 g of acetone is added to dissolve it, and then it is naturally dried at room temperature. Then, it is dried at 140°C for 3 hours using a hot air dryer (manufactured by Espec Corporation, product name "PHH-101"), and then it is cooled in a desiccator and the mass is measured. The solid content concentration (non-volatile content) of the polymer solution is calculated from the amount of mass loss. In the case of introducing the double bond, the double bond equivalent, which is the molecular weight per double bond of the polymer, is preferably in the range of 320 to 1800 g / mol, more preferably 330 to 1600 g / mol, still more preferably 400 to 1400 g / mol, particularly preferably 500 to 1200 g / mol, and most preferably 600 to 1200 g / mol. When the double bond equivalent is in the above range, the sensitivity to light is high, coloring during curing can be reduced, and storage stability is also improved. The double bond equivalent is the mass (g) of the solid content of the polymer solution per 1 mol of double bonds in the polymer. The mass of the solid content of the polymer solution is the sum of the masses of each monomer component constituting the polymer (the mass of the base polymer component and the mass of the compound having a functional group capable of bonding to an acid group and a polymerizable double bond group). The double bond equivalent can be determined by dividing the mass (g) of the polymer solid content of the polymer solution by the amount of double bonds (mol) of the polymer. The amount of double bonds in the polymer can be determined by confirming the structures of the acid group-containing monomer and the compound having a polymerizable double bond (the compound having a functional group capable of bonding to an acid group and a polymerizable double bond) used in the polymerization, and from the amounts thereof. It can also be measured by various analyses such as titration, elemental analysis, NMR, and IR, or by differential scanning calorimetry. For example, it may be calculated by measuring the number of ethylenic double bonds contained in 1 g of the polymer in accordance with the iodine value test method described in JIS K 0070:1992. The double bond equivalent is a measure of the amount of double bonds contained in a molecule. For compounds of the same molecular weight, the larger the double bond equivalent value, the smaller the amount of double bonds introduced. The range of the weight loss due to heat of the polymer is preferably 0 to 5%, more preferably 0 to 4%, still more preferably 0 to 3.5%, particularly preferably 0 to 3.2%, even more particularly preferably 0 to 3%, and most preferably 0 to 2.5%. When the weight loss due to heat is within the above range, the thermal decomposition resistance is high.

[0039] The polymerization method is not particularly limited, but may be a method in which all monomer components are charged in a solvent at once and polymerized, a method in which the remaining monomer components are continuously or gradually added to a reaction vessel in which a solvent and a portion of the monomer components have been charged in advance, and the like. In the polymer of the present invention, it is preferable to radically polymerize the above-mentioned monomer components using the above-mentioned polymerization initiator without using a thiol-based chain transfer agent. The pressure during the reaction is not particularly limited, and the reaction may be carried out under either normal pressure or pressurized conditions. The temperature during the polymerization reaction depends on the type and composition ratio of the raw material monomers used and the type of solvent used, but is usually preferably in the range of 20 to 150°C, more preferably 30 to 120°C. During the polymerization reaction, it is preferable to set the amount of the solvent and each monomer component so that the final solid content of the polymer solution is 10 to 70 mass%. In terms of productivity and polymerizability, the final solid content is more preferably 20 to 65 mass%, and even more preferably 25 to 60 mass%. The present invention also relates to a photosensitive resin composition comprising the above-mentioned radical polymerizable polymer, a polyfunctional monomer, a photopolymerization initiator, inorganic fine particles and a solvent. The use of the composition is not limited, but the composition is suitably used as a material for forming a protective film for color filters, liquid crystal display elements, integrated circuit elements, solid-state imaging elements and the like. In the photosensitive resin composition, the content of the radical polymerizable polymer is preferably 5% by mass or more, and preferably 70% by mass or less, relative to 100% by mass of the total solid content of the photosensitive resin composition. By being in such a range, the effects of the present invention can be more significantly exhibited. It is more preferably 10 to 65% by mass, even more preferably 10 to 50% by mass, particularly preferably 10 to 40% by mass, even more preferably 10 to 35% by mass, and most preferably 15 to 35% by mass.

[0040] In the photosensitive resin composition, the polyfunctional monomer is a low molecular weight compound having a polymerizable unsaturated bond (also referred to as a polymerizable unsaturated group) that can be polymerized by irradiation of active energy rays such as free radicals, electromagnetic waves (e.g., infrared rays, ultraviolet rays, X-rays, etc.), and electron beams. For example, a polyfunctional compound having two or more polymerizable unsaturated groups in a molecule can be mentioned. The molecular weight is not particularly limited, but from the viewpoint of handling, for example, it is preferably 3000 or less, and more preferably 2000 or less. Among them, a polyfunctional (meth)acrylate compound having two or more functions (hereinafter also simply referred to as a "polyfunctional (meth)acrylate compound") is particularly preferred. It is a compound having two or more (meth)acryloyl groups in one molecule. By including such a compound, the photosensitive resin composition has excellent photosensitivity and curability, and it is possible to obtain a cured film with extremely high hardness and high transparency. The number of functions of the polyfunctional (meth)acrylate compound is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. From the viewpoint of further suppressing cure shrinkage, the functionality is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. Examples of the polyfunctional monomer include polyfunctional (meth)acrylates such as (di)ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and tris(hydroxyethyl)isocyanurate tri(meth)acrylate. Among these, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-added dipentaerythritol hexa(meth)acrylate, propylene oxide-added trimethylolpropane tri(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, and ε-caprolactone-added dipentaerythritol hexa(meth)acrylate are preferred.

[0041] The content ratio of the polyfunctional monomer may be appropriately set according to the type of polyfunctional monomer and the radical polymerizable polymer used, as well as the purpose and application, but from the viewpoint of superior developability and plate making property, it is preferably 2% by mass or more and suitably 85% by mass or less with respect to 100% by mass of the total solid content of the photosensitive resin composition. The lower limit is more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 15% by mass or more, and the upper limit is more preferably 75% by mass or less, even more preferably 60% by mass or less, particularly preferably 50% by mass or less, and most preferably 40% by mass or less. The content of the polyfunctional monomer is preferably 50 parts by mass or more and 500 parts by mass or less relative to 100 parts by mass of the radical polymerizable polymer. When the content of the polyfunctional monomer is within this range, a cured film with higher surface hardness is obtained, and in combination with the preferred weight average molecular weight of the radical polymerizable polymer being 5000 or more, the developability is further improved. More preferably, the content is 80 parts by mass or more, even more preferably, 100 parts by mass or more, and particularly preferably, 120 parts by mass or more. In addition, from the viewpoint of further improving the developability, the content is more preferably 400 parts by mass or less. More preferably, the content is 300 parts by mass or less, particularly preferably, 200 parts by mass or less, and most preferably, 150 parts by mass or less. In the photosensitive resin composition, it is preferable to use a light or heat polymerization initiator when curing the photosensitive resin composition. Examples of the photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, oligo{2- Acetophenones such as 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one; benzoins such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone, o-benzoyl methyl benzoate, 4-phenylbenzophenone benzophenones such as 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzenemethanaminium bromide, and (4-benzoylbenzyl)trimethylammonium chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, Examples of thioxanthones include 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride, and the like. Other examples include phenylglyoxylic methyl ester, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and the like.Among these, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone are preferred.

[0042] Examples of the photopolymerization initiator include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropylcarbonate, t-amylperoxy-2-ethylhexanoate, and t-butylperoxy-2-ethylhexanoate; and azo compounds such as 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobis(2-methylpropionate). These photopolymerization initiators may be used alone or in combination of two or more.

[0043] Particularly preferred specific polymerization initiators include aminoketone compounds such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one ("IRGACURE907", manufactured by BASF), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 ("IRGACURE369", manufactured by BASF), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one ("IRGACURE379", manufactured by BASF); Titanocene compounds such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium ("IRGACURE784", manufactured by BASF); oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)] ("IRGACURE OXE01", manufactured by BASF); and the like. Among the above photopolymerization initiators, it is particularly preferable to use at least an aminoketone compound (also called an aminoketone polymerization initiator). That is, it is preferable that the photosensitive resin composition further contains an aminoketone polymerization initiator. This makes the hardness and heat resistance more excellent. The content of the photopolymerization initiator may be appropriately set according to the purpose, use, etc., and is not particularly limited, but is preferably 0.5 parts by mass or more relative to 100 parts by mass of the total solid content of the photosensitive resin composition. This makes it possible to obtain a cured film with better heat resistance. More preferably, it is 1 part by mass or more, and even more preferably, it is 1.5 parts by mass or more. In addition, in consideration of the balance between the influence of the decomposition product of the photopolymerization initiator and economic efficiency, it is preferably 30 parts by mass or less. More preferably, it is 20 parts by mass or less, and even more preferably, it is 10 parts by mass or less. The photosensitive resin composition preferably contains inorganic fine particles in order to increase the hardness of a cured film obtained by curing the photosensitive resin composition.

[0044] As inorganic fine particles, in addition to silicon oxide such as silica described above, metal oxides such as titanium oxide, aluminum oxide, zirconium oxide (zirconia, etc.), and metal salts such as calcium carbonate and barium sulfate are preferred. Among them, metal oxides are more preferred. They may be composite metal oxides containing two or more kinds of metal atoms. More preferred are metal oxide particles having hydroxyl groups on the surface, and particularly preferred are silica particles. Of these, surface-modified silica fine particles are preferred, and for example, it is even more preferred that they are surface-modified with (meth)acryloyloxy groups bonded to silicon atoms via a divalent linking group. The silica fine particles have hydroxyl groups on the particle surface, which further improves the affinity with the radical polymerizable polymer having a structural unit derived from an unsaturated monomer having a hydroxyl group and a structural unit derived from an α-(unsaturated alkoxyalkyl)acrylate monomer contained in the photosensitive resin composition of the present invention. The number average primary particle diameter (diameter of primary particles) of the inorganic fine particles is preferably, for example, 1 to 500 nm. Within this range, the inorganic fine particles have more sufficient dispersibility and dispersion stability, and it is possible to provide a cured film having excellent dispersibility and high transparency. The number average primary particle diameter is more preferably 1 to 300 nm, even more preferably 1 to 200 nm, particularly preferably 1 to 100 nm, and most preferably 1 to 50 nm. The number average primary particle diameter can be measured, for example, by using a laser diffraction particle size distribution analyzer. The number average primary particle diameter can be determined directly by magnifying and observing inorganic fine particles with a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), a field emission scanning electron microscope (FE-SEM), or the like, randomly selecting 100 primary particles, measuring their lengths in the major axis direction, and calculating the arithmetic average. The inorganic fine particles may be in the form of a dried powder or in the form of a dispersion (e.g., colloidal silica, etc.) dispersed in an organic solvent. From the viewpoint of the dispersion stability of the photosensitive resin composition, it is preferable to use the inorganic fine particles in the form of a dispersion dispersed in an organic solvent. That is, the inorganic fine particles are preferably contained in the photosensitive resin composition as an organic solvent dispersion. Examples of the particle shape include spherical, granular, elliptical, cubic, rectangular, pyramidal, needle-like, columnar, rod-like, cylindrical, flaky, plate-like, and thin-flaked shapes. Considering the dispersibility in the solvent, the particle shape is preferably spherical, granular, and columnar. Specific examples of the organic solvent include various solvents described in JP-A-2013-227485

[0024] . The organic solvent dispersion can be obtained by thoroughly dispersing inorganic fine particles in an organic solvent, but commercially available products can also be used. For example, various organosilica sols exemplified in JP2013-227485A (e.g., NBAC-ST (organosilica sol with butyl acetate as a dispersion medium) and the like) can be mentioned. When the photosensitive resin composition contains inorganic fine particles, the content (solid content) thereof is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of the total solid content of the photosensitive resin composition. From the viewpoints of developability, transparency, etc., the content is preferably 50% by mass or less, and more preferably 40% by mass or less.

[0045] When at least a silicon-containing compound (preferably silica fine particles) is used as the inorganic fine particles, the content (solid content) is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 90 parts by mass or more, and most preferably 100 parts by mass, based on 100 parts by mass of the total amount of the inorganic fine particles in the photosensitive resin composition. The photosensitive resin composition (preferably a negative photosensitive resin composition) of the present invention preferably contains a solvent as a diluent, if necessary. The solvent is not particularly limited as long as it can uniformly dissolve the above-mentioned polymer, polyfunctional monomer, photopolymerization initiator, inorganic fine particles, and other components. Specifically, for example, ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; chloroform, dimethyl sulfoxide, and the like can be mentioned. The content of the solvent may be appropriately set according to the optimal viscosity when the photosensitive resin composition is used. For example, it is 1000 parts by mass or less, more preferably 700 parts by mass or less, relative to 100 parts by mass of the polymer. The lower limit is preferably 30 parts by mass or more, more preferably 60 parts by mass or more, relative to 100 parts by mass of the polymer. By controlling the amount within the above numerical range, the handling property and storage stability of the composition, as well as the efficiency during application work, are improved. The viscosity of the photosensitive resin composition can be appropriately set according to the desired thickness of the cured film. The viscosity of the photosensitive resin composition can be adjusted by adding a solvent. The upper limit of the viscosity of the photosensitive resin composition adjusted to 40% solids (non-volatile content) by adding a solvent is, for example, preferably 100 mPa·s or less, more preferably 50 mPa·s or less, and particularly preferably 15 mPa·s or less. The lower limit of the viscosity is, for example, preferably 1 mPa·s or more, more preferably 5 mPa·s or more, depending on the desired thickness of the cured film. By setting the viscosity within the above range, the handling property and the coating workability are improved.

[0046] In addition to the above-mentioned components, the photosensitive resin composition of the present invention may contain known additives such as fillers such as aluminum hydroxide, talc, clay, and barium sulfate, quantum dot particles, dyes, pigments, defoamers, coupling agents, leveling agents, sensitizers, release agents, lubricants, plasticizers, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, polymerization inhibitors, polymerization retarders, polymerization accelerators, thickeners, dispersants, and surfactants, within the scope of the effects of the present invention. As the pigment, one or more of various organic or inorganic colorants can be used. As the organic colorant, dyes, organic pigments, natural dyes, and the like can be used.

[0047] The present invention also relates to a cured film obtained by curing the radical polymerizable polymer and / or the photosensitive resin composition. Examples of materials used as substrates to be coated include transparent materials such as glass, acrylic resin, polycarbonate resin, polyester resin such as PET, polystyrene resin, and metal materials such as aluminum, copper, iron, and stainless steel. The cured film preferably has a film thickness of 0.1 to 20 μm. This can fully meet the demand for low height of components and display devices using the cured film. The film thickness is more preferably 0.5 to 10 μm, and even more preferably 0.5 to 8 μm. Specifically, the light transmittance of the cured film can be 70% or more, preferably 75% or more, more preferably 80% or more, at a thickness of 130 μm, for light having a wavelength of 410 nm. Thus, the cured film obtained from the photosensitive resin composition of the present invention is preferably highly transparent. Thus, for example, even when a laminate including the cured film is used in a touch panel, it is possible to display a clear image without deteriorating the display performance. The surface hardness of the cured film is high because the photosensitive resin composition is cured. This allows the film to absorb external impacts when used as a component of a protective film or insulating film. In terms of pencil hardness, the hardness decreases in the following order: 4H>3H>2H>H>F>HB>B>2B>3B>4B. The radical polymerizable polymer of the present invention is excellent in transparency and heat resistance (particularly resistance to thermal decomposition) and can be used for applications such as resist materials, various coating agents, paints, etc. In addition, since the polymer has an acid group such as a carboxyl group, it can be suitably used as an alkali-developable negative resist material for producing colored pixels of color filters, black matrices, overcoats, photospacers, optical waveguides, etc. EXAMPLES

[0048] The present invention will be described in more detail below with reference to examples. However, the following examples do not limit the present invention, and all modifications and variations within the scope of the present invention are included in the technical scope of the present invention. The present invention will be specifically illustrated by examples, comparative examples, and property evaluations. In the examples and comparative examples, % and wt% mean mass %, and parts mean mass parts, unless otherwise specified. In the following Production Examples, various physical properties were evaluated as follows. [Evaluation method] (1) Weight average molecular weight: Mw Measurements were performed using GPC (HLC-8220GPC, manufactured by Tosoh Corporation) with THF as the eluent and a TSKgel SuperHZM-N (manufactured by Tosoh Corporation) column, and calculations were made in terms of standard polystyrene. (2) Solids Approximately 0.3 g of the copolymer solution prepared in the manufacturing example was weighed out in an aluminum cup, and about 1 g of acetone was added to dissolve it, and then it was naturally dried at room temperature. After that, it was dried at 140°C for 3 hours using a hot air dryer (product name: PHH-101, manufactured by Espec Corporation), and then it was cooled in a desiccator and its weight was measured. From the weight loss, the weight of the solid content (resin) of the polymer solution was calculated. (3) Acid value 1.5 g of the copolymer solution prepared in the Production Example was precisely weighed out, dissolved in a mixed solvent of 90 g of acetone and 10 g of water, and titrated with a 0.1 N KOH aqueous solution. The titration was performed using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of polymer was calculated from the solid content concentration (mg KOH / g). (4) Thermogravimetric reduction A solution of 2 g of the copolymer solution prepared in the Production Example and 4 g of tetrahydrofuran was added dropwise to 60 g of hexane, and the precipitated acrylic resin was separated, taken out, and vacuum dried overnight at 40° C. 10 mg of the obtained acrylic resin powder was weighed out, and the weight loss rate at 230° C. for 30 minutes under a nitrogen atmosphere was measured using a thermogravimetric analyzer TGA-50 (manufactured by SHIMADZU). The smaller the weight loss rate, the higher the thermal decomposition resistance.

[0049] [Production of radically polymerizable polymer] The following radical polymerizable polymers were used. [Production Example 1] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of (α-allyloxymethyl)methyl acrylate (AOMA), 37 g of methacrylic acid (MAA), 37 g of cyclohexyl methacrylate (CHMA), 1 g of methyl methacrylate (MMA), 10 g of 2-hydroxyethyl acrylate (HEA), and 8 g of t-butylperoxy-2-ethylhexanoate (trade name "Perbutyl (registered trademark) O", manufactured by Nippon Oil & Fats Co., Ltd., hereinafter also referred to as PBO) were charged as a monomer composition into a monomer dropping vessel and mixed by stirring.

[0050] 233g of propylene glycol methyl ether acetate (PGMEA) was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 33g of glycidyl methacrylate (GMA), 0.2g of Antage W-400 (manufactured by Kawaguchi Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.4g of triphenylphosphine (TPP) as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature to obtain a copolymer solution (A-1) containing 36.2% by weight of resin. The resin had a weight average molecular weight (Mw) of 12000 and an acid value of 90 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution are shown in Table 1 along with Production Examples 2 to 7. [Production Example 2] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of AOMA, 37 g of MAA, 37 g of CHMA, 1 g of MMA, 10 g of 2-hydroxypropyl methacrylate (HPMA), and 16 g of PBO were added as a monomer composition to a monomer dropping vessel and mixed with stirring.

[0051] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 17g of GMA, 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 14 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-2) containing 33.5% by weight of resin. The weight average molecular weight (Mw) of the resin was 5000 and the acid value was 150 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution are shown in Table 1. [Production Example 3] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of AOMA, 33 g of MAA, 31 g of CHMA, 1 g of MMA, 20 g of 2-hydroxyethyl methacrylate (HEMA), and 12 g of PBO were added as a monomer composition to a monomer dropping vessel and mixed with stirring.

[0052] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 7 / 93 (v / v) mixed gas was started. Next, 38g of Cyclomer M100 (manufactured by Daicel, hereinafter M100), 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and reacted at 115°C for 21 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-3) containing 37.0% by weight of resin. The weight average molecular weight (Mw) of the resin was 8000 and the acid value was 89 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution are shown in Table 1. [Production Example 4] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of AOMA, 44 g of acrylic acid (AA), 30 g of CHMA, 1 g of MMA, 10 g of HEMA, and 16 g of PBO were charged as a monomer composition in a monomer dropping vessel and mixed with stirring.

[0053] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 69g of GMA, 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 14 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-4) containing 42.1% by weight of resin. The weight average molecular weight (Mw) of the resin was 9200 and the acid value was 50 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution are shown in Table 1. [Production Example 5] A separable flask equipped with a cooling tube was prepared as a reaction vessel. Meanwhile, 15 g of methylmaleimide (MMI), 55 g of AA, 30 g of t-butyl methacrylate (tBMA), and 16 g of PBO were added as a monomer composition to a monomer dropping vessel and mixed with stirring.

[0054] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 89g of GMA, 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 14 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-5) containing 45.0% by weight of resin. The weight average molecular weight (Mw) of the resin was 9500 and the acid value was 50 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution are shown in Table 1. [Production Example 6] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 37 g of MAA, 37 g of CHMA, 1 g of MMA, 25 g of tBMA, and 10 g of PBO were charged as a monomer composition into a monomer dropping vessel and mixed with stirring.

[0055] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 33g of GMA, 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 14 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-6) containing 36.5% by weight of resin. The weight average molecular weight (Mw) of the resin was 10,500 and the acid value was 89 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution are shown in Table 1. [Production Example 7] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of AOMA, 15 g of MAA, 37 g of CHMA, 23 g of MMA, 10 g of HEMA, and 8 g of PBO were charged as a monomer composition in a monomer dropping vessel and mixed with stirring.

[0056] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, it was cooled to room temperature to obtain a copolymer solution (A-7) containing 30.3% by weight of resin. The weight average molecular weight (Mw) of the resin was 6000 and the acid value was 100mgKOH / g. Table 1 shows the production conditions, solid content concentration (non-volatile content), weight average molecular weight (Mw), thermal weight loss, and acid value of the copolymer solution. [Production Example 8] A separable flask equipped with a cooling tube was prepared as a reaction vessel. Meanwhile, 15 g of AOMA, 55 g of AA, 30 g of CHMA, and 16 g of PBO were added as a monomer composition to a monomer dropping vessel and mixed with stirring.

[0057] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 89g of GMA, 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 14 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-8) containing 44.9% by weight of resin. The weight average molecular weight (Mw) of the resin was 9800 and the acid value was 52 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw) and acid value of the copolymer solution are shown in Table 1. [Production Example 9] A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of AOMA, 22 g of MAA, 37 g of CHMA, 16 g of MMA, 10 g of HEMA, and 8 g of PBO were charged as a monomer composition into a monomer dropping vessel and mixed with stirring.

[0058] 233g of PGMEA was charged into the reaction vessel, and after replacing with nitrogen, the temperature of the reaction vessel was raised to 90°C by heating in an oil bath while stirring. After the temperature of the reaction vessel stabilized at 90°C, the monomer composition was added dropwise. While maintaining the temperature at 90°C, the monomer composition was added dropwise over 180 minutes. After the monomer composition was added dropwise, 0.5g of PBO was added. After another 30 minutes, the vessel was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, a gas inlet tube was attached to the separable flask, and bubbling of a mixed gas of oxygen / nitrogen = 7 / 93 (v / v) was started. Next, 8.6g of GMA, 0.2g of Antage W-400 as a polymerization inhibitor, and 0.4g of TPP as a catalyst were charged into the reaction vessel, and the reaction was carried out at 115°C for 7 hours. After that, it was cooled to room temperature to obtain a copolymer solution (A-9) containing 31.7% by weight of resin. The weight average molecular weight (Mw) of the resin was 6300 and the acid value was 99 mgKOH / g. The production conditions, solid content (non-volatile content), weight average molecular weight (Mw) and acid value of the copolymer solution are shown in Table 1. Regarding the above radically polymerizable polymers, the compositions of A-1 to A-4 (Examples 1 to 4) and A-5 to A-9 (Comparative Examples 1 to 5) are shown in Table 1.

[0059] [Table 1]

[0060] [Preparation of photosensitive resin composition] 3.31 g of the copolymer solution (A-1) as the binder resin (i.e., 1.2 g of resin), 4.00 g of PGM-AC-4130Y as inorganic fine particles (silica fine particles) (1.2 g of non-volatile content: manufactured by Nissan Chemical), 1.54 g of DPHA as a polyfunctional monomer, and 0.06 g of 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one (trade name "IRGACURE (registered trademark) 907", manufactured by BASF Japan, hereinafter referred to as Irg907) as a photopolymerization initiator were added, and diluted with PGMEA so that the non-volatile content concentration became 40% by weight, to prepare photosensitive resin composition B1. Similarly, photosensitive resin compositions B2 to B9 were prepared using the copolymer solutions (A-2 to A-9) as the binder resin. The compositions of photosensitive resin compositions B1 to B4 (Examples 5 to 8) and photosensitive resin compositions B5 to B9 (Comparative Examples 6 to 10) are shown in Table 2. The viscosity of Resin Composition B at 25° C. was measured using a cone-plate type rotational viscometer (TVE22LT, manufactured by Toki Sangyo Co., Ltd.). The cone plate used was a standard rotor (name: 1°34´×R24). <Curing method> The above photosensitive resin compositions B1 to B10 were applied onto a 5 cm square glass substrate using a spin coater and dried in an oven at 80° C. for 3 minutes. After drying, the substrate was irradiated with 1 J / cm 2 using a UV aligner (product name "TME-150RNS", manufactured by TOPCON Corporation) equipped with a 2.0 kW ultra-high pressure mercury lamp. 2 (converted into 365 nm illuminance). After UV irradiation, the coating was post-cured at 160° C. for 1 hour to completely cure the coating. The resulting coating was subjected to the following evaluations (5) and (6). The results are shown in Table 2. (5)Pencil hardness The tests were conducted in accordance with JIS-K5600-5-4 (1999), but all tests were conducted using a load of 500g, as specified in the old JIS version of JIS-K5400 (1990), and the hardest pencil that did not produce a scratch was recorded as the hardness (surface hardness) value. (6) Transmittance Using a glass substrate as a blank, the light transmittance of the coating film was measured with a spectrophotometer UV3100 (manufactured by Shimadzu Corporation) to determine the transmittance at 410 nm.

[0061] [Table 2]

[0062] The abbreviations are as follows: Irg907: IRGACURE® 907, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one DPHA: Dipentaerythritol hexaacrylate Comparison of the Examples and Comparative Examples in Table 1 confirmed the superiority of the radical polymerizable polymer of the present invention. Specifically, polymers having specific structural units, double bond equivalents of 330 to 1600 (g / mol), and acid values ​​of 50 to 150 (mgKOH / g) were highly resistant to thermal decomposition. In addition, although not shown in the table, Examples 1 to 4 were highly transparent. In particular, a remarkable effect of Examples 1 to 4 was confirmed in comparison with Comparative Examples 1 and 2, which did not contain structural units derived from AOMA but contained structural units derived from tBMA. The content of structural units derived from tertiary carbon-containing (meth)acrylate monomers (tBMA) is preferably 5% by mass or less. Comparison of the Examples and Comparative Examples in Table 2 confirmed the superiority of the photosensitive resin composition of the present invention. Specifically, the compositions of Examples 5 to 8 had low viscosity and high coating workability. In addition, the obtained cured films have high light transmittance at 410 nm, making them suitable for the optical field. Furthermore, the surface hardness of the cured films obtained from the compositions of Examples 5 to 8 is higher than that of Comparative Examples 8 and 10, which is believed to be due in large part to the fact that a specific range of polymerizable double bonds is provided to the side chain of the polymer. [Industrial Applicability]

[0063] The radically polymerizable polymer and photosensitive resin composition of the present invention can be applied, for example, to resist materials, and can be suitably used in the fields of optics and electric / electronics.

Claims

1. A radically polymerizable polymer having a polymerizable double bond in a side chain, the polymer comprising a constituent unit derived from an unsaturated monomer having an acid group, a constituent unit derived from an unsaturated monomer having a hydroxyl group, and a constituent unit represented by the following formula (1), the double bond equivalent of the polymer being 330 to 1600 (g / mol), an acid value being 50 to 150 (mgKOH / g), and a weight average molecular weight being 5000 to 9200: 【Chemistry 1】 (R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.)

2. 2. The radical polymerizable polymer according to claim 1, wherein the double bond equivalent of the polymer is 500 to 1200 (g / mol).

3. 3. The radical polymerizable polymer according to claim 1, wherein the content of structural units derived from a tertiary carbon-containing (meth)acrylate monomer is 5% by mass or less relative to 100% by mass of all structural units of the radical polymerizable polymer.

4. 4. A photosensitive resin composition comprising the radical polymerizable polymer according to claim 1, a polyfunctional monomer, a photopolymerization initiator, inorganic fine particles, and a solvent.

5. A photosensitive resin composition as described in claim 4, wherein the viscosity of the photosensitive resin composition adjusted to a solid content of 40% is 1 mPa·s or more and 12 mPa·s or less.

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