Radical polymerizable polymer and photosensitive composition

Abstract

To provide a radically polymerizable polymer capable of forming a coating film excellent in heat resistance, adhesiveness and coating property, and to provide a photosensitive resin composition comprising the polymer.SOLUTION: There is provided a radically polymerizable polymer, which 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 5- or more-membered cyclic ether structure; a structural unit having a ring structure in its main chain; and polymerizable double bond in a side chain, and the polymer has a weight-average molecular weight of 19,000 or less. The radically polymerizable polymer has a double bond equivalent of 300 to 2000 (g / mol), and a content ratio of a structural unit having a ring structure in the main chain is preferably 9 mass% or more with respect to 100 mass% of the total structural units of the radically polymerizable polymer. It is also a photosensitive resin composition containing the radically 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] Curable resin compositions that can be cured by heat or active energy rays have been widely studied for their application to various applications, such as various optical components and electrical and electronic devices, including color filters, inks, printing plates, printed wiring boards, semiconductor elements, and photoresists used in liquid crystal displays and solid-state imaging devices, and excellent curable resin compositions have been developed to suit the properties required for each application. For example, Patent Document 1 describes a radiation-sensitive resin composition that can provide an interlayer insulating film with high resolution and excellent heat-resistant dimensional stability, heat-resistant discoloration, and adhesion to a substrate, and contains [A] an alkali-soluble resin, [B] a 1,2-quinonediazide compound, and [C] a radical scavenger. The alkali-soluble resin is a copolymer having various structural units. Furthermore, as a photosensitive resin composition capable of providing a cured film exhibiting excellent shielding portion curability, high heat resistance, high adhesion, and high transparency, for example, Patent Document 2 describes an active energy ray-curable photosensitive resin composition containing (A) a (meth)acrylate having a cyclic ether skeleton, (B) an alkyl (meth)acrylate having 1 to 24 carbon atoms in the alkyl group, (C) a (meth)acrylic resin which is a copolymer of at least two kinds of radically polymerizable monomers, and (D) a polymerization initiator.

[0003] As described above, the level of various properties required for optical materials is increasing, and there is a demand for polymers and photosensitive resin compositions thereof that are easy to handle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Republished Publication No. WO2011-046230 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-36024 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above-mentioned current situation, an object of the present invention is to provide a radical polymerizable polymer that is easy to handle and has excellent coating workability, and that can give a cured product that is excellent in hardness, heat resistance, and adhesion, and a photosensitive resin composition containing the radical polymer. [Means for solving the problem]

[0006] The present inventors have conducted extensive research into polymers and have found that the problems can be solved by a radically polymerizable polymer having a weight-average molecular weight of 19,000 or less, which polymer contains a structural unit derived from an unsaturated monomer having an acid group, a structural unit derived from an unsaturated monomer having a cyclic ether structure with five or more members, a structural unit having a ring structure in the main chain, and a polymerizable double bond in the side chain. Preferably, the radical polymerizable polymer has a double bond equivalent of 300 to 2000 (g / mol), and more preferably, the content of structural units having a ring structure in the main chain is 9% by mass or more relative to 100% by mass of all structural units of the radical polymerizable polymer. More preferably, the content of structural units derived from unsaturated monomers having a cyclic ether structure of five or more members is 7.5% by mass or more relative to 100% by mass of all structural units of the radical polymerizable polymer. 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. [Effects of the Invention]

[0007] The radical polymerizable polymer and photosensitive resin composition of the present invention can form a coating film that has excellent heat resistance (particularly thermal decomposition resistance), adhesion, and coatability, and can be suitably used in applications such as resist materials, various coating agents, paints, etc. Furthermore, the present invention can provide a cured film with high hardness. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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 addition, 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 preferred numerical values ​​are given in stages for the upper and lower limit values, a numerical range obtained by appropriately combining the separately given upper and lower limit values ​​is also a preferred numerical range. As described above, the polymer of the present invention is a radically polymerizable polymer that has a constitutional unit derived from an unsaturated monomer having an acid group, a constitutional unit derived from an unsaturated monomer having a cyclic ether structure with five or more members, a constitutional unit having a ring structure in the main chain, and a polymerizable double bond in the side chain, and that has a weight-average molecular weight of 19,000 or less. 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, for example. The structure in which the polymerizable double bond is opened is, for example, a structure in which a carbon-carbon double bond (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 exhibits acidity in water, but a carboxyl group is preferred. A preferred embodiment is a radically polymerizable polymer having a double bond equivalent of 300 to 2000 (g / mol) obtained by reacting a polymer (also referred to as a base polymer) obtained by copolymerizing (A) an unsaturated monomer having a carboxyl group, (B) an unsaturated monomer having at least one selected from a tetrahydrofuran ring, a dioxolane ring, a tetrahydropyran ring, and a dioxane ring, and (C) at least one monomer selected from an N-substituted maleimide monomer, a dialkyl-2,2'-(oxydimethylene)diacrylate monomer, and an α-(unsaturated alkoxyalkyl)acrylate monomer as essential components with an unsaturated monomer having an epoxy group. The polymer of the present invention also includes a polymer having a structural unit derived from an unsaturated monomer having an acid group, 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.

[0009] 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 the manufacture of liquid crystal display panels such as color filters and black matrices. In particular, the obtained cured film has high hardness and high transparency, making it very useful as a protective film or insulating film in various display devices. The display device is not particularly limited, but suitable examples include liquid crystal display devices, solid-state imaging devices, and touch panel display devices. As touch panel display devices, capacitance type devices are particularly preferred. The radically polymerizable polymer of the present invention is a photosensitive alkali-soluble resin and exhibits good developability. Preferred acid groups contained in the alkali-soluble resin include unsaturated monomers (preferably (meth)acrylates) having a carboxyl group, such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, and 2-(meth)acryloyloxyethyl phthalic acid. Among these, (meth)acrylic acid is particularly preferred. The content of the carboxyl group-containing unsaturated monomer is preferably 0.5 to 50% by mass, more preferably 2 to 50% by mass, even more preferably 5 to 45% by mass, and particularly preferably 5 to 40% by mass, of the total monomer components (100% by mass of the base polymer). Within this range, the solubility in alkaline substances is sufficient, and the resulting polymer does not become too viscous, resulting in good handleability. The proportion of structural units derived from unsaturated monomers having an acid group in all structural units is preferably within the above-mentioned range (0.5 to 50 mass%), and is preferably 1 to 40 mass% relative to 100 mass% of a radically polymerizable polymer having a weight-average molecular weight of 19,000 or less.

[0010] Furthermore, as the unsaturated monomer having a cyclic ether structure of 5 or more members, which is an essential component of the polymer of the present invention, an unsaturated monomer having a cyclic ether structure of 5 to 10 members is preferred, an unsaturated monomer having a cyclic ether structure of 5 to 8 members is more preferred, and an unsaturated monomer having a cyclic ether structure of 5 or 6 members is particularly preferred. Furthermore, an unsaturated monomer having a cyclic ether structure in a side chain via a linker (e.g., an organic group containing an ester bond) is preferred. Examples include unsaturated monomers having a cyclic ether structure selected from a tetrahydrofuran ring, a dioxolane ring, a tetrahydropyran ring, and a dioxane ring. That is, the (meth)acrylate has a cyclic ether structure of 5 or more members, and the number of (meth)acryloyl groups per molecule is one. The acryloyl group is preferably bonded to the cyclic ether structure of 5 or more members via a linker. Examples of linkers include -O- (i.e., an ether bond), *-O-C1-6 alkylene group-**, *-O-C1-6 alkylene group-COO-**, etc. The linker is preferably -O- or *-O-CH2-**. In the above formula, * indicates the bonding position to the acryloyl group, and ** indicates the bonding position to the cyclic ether structure having five or more members. The (meth)acryloyl monomer having a cyclic ether structure of five or more members is preferably a monomer having a glass transition temperature of -30°C or higher, and 100°C or lower, when polymerized, of the (meth)acryloyl monomer having a cyclic ether structure. The five- or more-membered cyclic ether structure preferably contains at least one selected from a tetrahydrofuran structure, a dioxolane structure, a tetrahydropyran structure, and a dioxane structure, and is particularly preferably a tetrahydrofuran structure or a dioxolane structure. The tetrahydrofuran structure is represented by the following formula (B1), the dioxolane structure is represented by the following formula (B2i) or formula (B2ii), the tetrahydropyran structure is represented by the following formula (B3), and the dioxane structure is represented by any of the following formulas (B4i) to (B4iii) (in the following formulas, * represents a bonding position). These cyclic ethers may have a C1-20 linear, branched or alicyclic alkyl substituent.

[0011] [ka] The dioxolane structure is preferably a 1,3-dioxolane structure (the above formula (B2ii)). The dioxane structure is preferably a 1,3-dioxane structure (the above formula (B4ii)) or a 1,4-dioxane structure (the above formula (B4iii)), more preferably a 1,3-dioxane structure. Specifically, (meth)acrylates having a tetrahydrofuran ring (structure) include tetrahydrofurfuryl (meth)acrylate and γ-caprolactone-modified tetrahydrofurfuryl (meth)acrylate; (meth)acrylates having a dioxolane ring (structure) include (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate and (2,2-cyclohexyl-1,3-dioxolan-4-yl)methyl (meth)acrylate; and (meth)acrylates having a dioxane ring include dioxane glycol di(meth)acrylate and (5-ethyl-1,3-dioxan-5-yl)methyl (meth)acrylate. Each of the above (meth)acrylates may be used alone or in combination of two or more. From the viewpoint of dispersibility of inorganic fine particles, preferred are (meth)acrylates having a tetrahydrofuran ring, (meth)acrylates having a dioxolane ring, and (meth)acrylates having a dioxane ring, and more preferred are (meth)acrylates having a tetrahydrofuran ring and (meth)acrylates having a dioxolane ring. Examples of commercially available products include Light Acrylate THF-A manufactured by Kyoeisha Chemical Co., Ltd. and MEDOL10 manufactured by Osaka Organic Chemical Industry Co., Ltd. The content of the unsaturated monomer having a cyclic ether structure of five or more members is preferably in the range of 8 to 40% by mass, more preferably 10 to 40% by mass, and even more preferably 10 to 35% by mass, of the total monomer components (100% by mass of the base polymer). Within this range, adhesion and dispersibility of inorganic fine particles are improved. The content of the structural units derived from the unsaturated monomer having a cyclic ether structure of five or more members is preferably in the above-mentioned range (8 to 40% by mass) of all structural units. Furthermore, for example, the content is preferably 3 to 40% by mass, more preferably 7.5 to 35% by mass, of a radically polymerizable polymer having a weight-average molecular weight of 19,000 or less obtained by reacting an unsaturated monomer having an epoxy group. The structural unit having a ring structure in the main chain, which is an essential unit of the radically polymerizable polymer of the present invention, is a structural unit derived from an unsaturated monomer (including an unsaturated monomer having a ring structure in the main chain) that can introduce a ring structure into the main chain of the polymer, and is preferably a structural unit derived from, for example, an N-substituted maleimide monomer, a dialkyl-2,2'-(oxydimethylene)diacrylate monomer (also called an ether dimer), or an α-(unsaturated alkoxyalkyl)acrylate monomer (preferably an alkyl-(α-allyloxymethyl)acrylate monomer). Here, for example, the use of an N-substituted maleimide monomer and / or a dialkyl-2,2'-(oxydimethylene)diacrylate monomer and / or an alkyl-(α-allyloxymethyl)acrylate monomer results in an alkali-soluble resin that can provide a cured product with improved heat resistance, hardness, inorganic fine particle dispersibility, etc. when used in a photosensitive resin composition (resist). The content of the monomer capable of introducing a ring structure into the main chain is preferably 0.5 to 45% by mass, and more preferably 1 to 35% by mass, based on 100% by mass of the total amount of all monomer components. In particular, when an N-substituted maleimide monomer, a dialkyl-2,2'-(oxydimethylene)diacrylate monomer, and / or an α-(unsaturated alkoxyalkyl)acrylate monomer is included, the content is preferably 1 to 40% by mass, more preferably 1.5 to 35% by mass, and even more preferably 2 to 30% by mass, from the viewpoints of heat resistance, hardness, and coatability due to reduced viscosity of the polymer or a composition containing the polymer. The proportion of the structural unit having a ring structure in the main chain within the total structural units is preferably within the above-mentioned range (0.5 to 45% by mass). Furthermore, for example, relative to 100% by mass of a radically polymerizable polymer having a weight average molecular weight of 19,000 or less obtained by reacting an unsaturated monomer having an epoxy group, the content is preferably 1.5 to 40% by mass, more preferably 5 to 35% by mass, particularly preferably 9 to 30% by mass, and most preferably 15 to 30% by mass. 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 cyclopolymerization to form a polymer having a ring structure in the main chain. In the present invention, the above-mentioned monomers do not fall under the category of unsaturated monomers having a cyclic ether structure with a five- or more-membered ring. Examples of the N-substituted maleimide monomer include N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, Nt-butylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, and N-naphthylmaleimide, and one or more of these can be used. Among these, N-cyclohexylmaleimide, N-phenylmaleimide, and N-benzylmaleimide are preferred in terms of excellent adhesion and dispersibility, and N-benzylmaleimide and N-phenylmaleimide are particularly suitable. 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; and halogen-substituted benzylmaleimides such as o-chlorobenzylmaleimide, o-dichlorobenzylmaleimide and p-dichlorobenzylmaleimide. Examples of the N-phenylmaleimide include phenylmaleimide; alkyl-substituted phenylmaleimides such as p-methylphenylmaleimide and p-butylphenylmaleimide; phenolic hydroxyl group-substituted phenylmaleimides such as p-hydroxyphenylmaleimide; and halogen-substituted phenylmaleimides such as o-chlorophenylmaleimide, o-dichlorophenylmaleimide and p-dichlorophenylmaleimide. As the dialkyl-2,2'-(oxydimethylene)diacrylate monomer, it is preferable to use, for example, dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, etc., from the viewpoints of low coloration, dispersibility, ease of industrial availability, etc. 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 α-(allyloxymethyl)acrylates containing a chain saturated hydrocarbon group, such as 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. Additionally, alkyl-(α-methallyloxymethyl)acrylate monomers are also preferred, and among these, methyl α-allyloxymethylacrylate (also referred to as α-(allyloxymethyl)methyl acrylate) is particularly preferred. The α-(unsaturated alkoxyalkyl)acrylate monomer can be produced, for example, by the production method disclosed in International Publication No. 2010 / 114077. The above monomers can be used alone or in combination of two or more. The monomer components used to obtain the radically polymerizable polymer of the present invention may contain, as necessary, other copolymerizable monomers in addition to the essential components of an unsaturated monomer having an acid group (preferably a carboxyl group), an unsaturated monomer having a cyclic ether structure with five or more members, and an unsaturated monomer capable of introducing a cyclic structure into the main chain. Examples of such 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. Examples include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2,3-hydroxypropyl (meth)acrylate. Also, (meth)acrylamides such as N,N-dimethyl(meth)acrylamide and N-methylol(meth)acrylamide; macromonomers having a (meth)acryloyl group at one end of the polymer molecular chain such as polystyrene, polymethyl(meth)acrylate, polyethylene oxide, polypropylene oxide, polysiloxane, polycaprolactone, and polycaprolactam; conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, and 2-ethylhexyl vinyl ethers such as methyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, 2-hydroxyethyl vinyl ether, and 4-hydroxybutyl vinyl ether; N-vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinylmorpholine, and N-vinylacetamide; and unsaturated isocyanates such as isocyanatoethyl (meth)acrylate and allyl isocyanate. In addition, aromatic vinyl compounds such as styrene, vinyl toluene, and α-methyl styrene; ethylene or substituted ethylene compounds such as ethylene, propylene, vinyl chloride, and acrylonitrile; and the like may be copolymerized to the extent that the heat resistance is not affected. Among these, methyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate are preferred because they have good transparency and are less likely to impair heat resistance. Hydroxyl-containing monomers such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate are also preferred because they reduce viscosity. These other copolymerizable monomers may be used alone or in combination of two or more. In addition, 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 or two or more types. The content of structural units derived from other monomers is preferably 0 to 60 mass%, more preferably 0.3 to 50 mass%, even more preferably 0.5 to 40 mass%, and particularly preferably 1 to 30 mass%, relative to 100 mass% of all structural units in the radically polymerizable polymer. In the present invention, polymers that lose weight upon heating are undesirable, and therefore the content of structural units derived from tertiary carbon-containing (meth)acrylate monomers, such as t-butyl (meth)acrylate and / or t-amyl (meth)acrylate, is preferably low. This is because heating can cleave the O-C bond between the oxygen atom adjacent to the (meth)acryloyl group and the tertiary carbon atom adjacent thereto. The proportion of the tertiary carbon-containing (meth)acrylate monomer is not particularly limited depending on the application. However, in consideration of minimizing thermal weight loss and transparency, it is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, particularly preferably 0 to 1% by mass, and most preferably substantially absent, of the total monomer components. The proportion of structural units derived from tertiary carbon-containing (meth)acrylate monomers is preferably within the above-mentioned range of 0 to 5% by mass (5% by mass or less) of the total structural units. Furthermore, the radically 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, the polymer can be cured by heat or light. Therefore, when formed into a photosensitive resin composition, the sensitivity to light is improved, the polymer can be cured with a smaller amount of light, and the mechanical strength after curing is also increased. A method for introducing a polymerizable double bond into the side chain includes adding a compound containing at least one group selected from the group consisting of an epoxy group, an oxazoline group, and a hydroxyl group and a polymerizable unsaturated double bond. In terms of the reactivity of the resulting polymer, the double bond possessed by a (meth)acryloyl group is preferred as the polymerizable unsaturated double bond. The polymer before the addition of a polymerizable double bond to the side chain is also referred to as the base polymer.

[0012] 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; and compounds having an oxazoline group and a double bond, such as vinyloxazoline and isopropenyloxazoline. Preferred examples include compounds having an epoxy group and a carbon-carbon double bond, such as glycidyl (meth)acrylate, allyl glycidyl ether, α-ethylglycidyl (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 because of their high reactivity, ease of reaction control, availability, and the ability to 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 adjusting the amount within the above range, the exposure sensitivity, developability, and storage stability become good.

[0013] The double bond equivalent of the radically polymerizable polymer is preferably 300 to 2000 g / equivalent (mol). When the double bond equivalent is within the above range, the curability (sensitivity to heat and light) of the radically polymerizable polymer is improved, and the adhesiveness of the cured product is improved. Furthermore, coloration during curing can be reduced. From the viewpoint of achieving both curability and storage stability, the double bond equivalent is preferably 350 g / equivalent or more, more preferably 400 g / equivalent or more, even more preferably 500 g / equivalent or more, and particularly preferably 550 g / equivalent or more. From the viewpoint of curability and dispersibility, the double bond equivalent is preferably 1600 g / equivalent or less, more preferably 1400 g / equivalent or less, and even more preferably 1200 g / equivalent or less. As used herein, the double bond equivalent refers to the mass (g) of the solid content of a 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 the monomer components constituting the polymer (e.g., 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) in 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 determining their amounts. It can also be measured by various analyses such as titration, elemental analysis, NMR, and IR, or by differential scanning calorimetry. For example, it can be calculated by measuring the number of ethylenic double bonds contained per gram of 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, and for compounds of the same molecular weight, the larger the double bond equivalent value, the smaller the amount of double bonds introduced. The weight-average molecular weight of the radically polymerizable polymer is 19,000 or less. It is preferably 3,000 to 19,000, and more preferably 5,000 to 17,000. The number-average molecular weight is preferably 1,000 to 8,000, and more preferably 2,000 to 5,000. When the weight-average molecular weight is within the above range, the viscosity can be adjusted to an appropriate range, resulting in good handleability (applicability) and further improved adhesion. The weight-average molecular weight is more preferably 5,000 to 13,000, particularly preferably 5,000 to 11,000, and most preferably 6,000 to 10,000. The weight-average molecular weight can be determined, for example, by GPC (gel permeation chromatography) using polystyrene as a standard substance and tetrahydrofuran (THF) as an eluent, using an HLC-8220GPC (manufactured by Tosoh Corporation) and a TSKgel SuperHZM-N column (manufactured by Tosoh Corporation). The acid value of the radically polymerizable polymer is preferably 50 to 180 mgKOH / g. When the acid value is within the above range, not only is alkali solubility enhanced, but the adhesion of the cured product is further improved, and the dispersibility of inorganic fine particles is more appropriate. The dispersibility of the radically polymerizable polymer is also improved. Therefore, the photosensitive resin composition does not become too viscous and has good coatability. The acid group content is more preferably 60 to 150 mgKOH / g, and even more preferably 70 to 150 mgKOH / g. The acid value of the polymer can be determined, for example, by measuring the acid value of a polymer solution using a 0.1N KOH aqueous solution as a titrant with an automatic titrator (manufactured by Hiranuma Sangyo Co., Ltd., product name "COM-555"), and then 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 also be determined as follows. Approximately 0.3 g of the polymer solution was weighed into an aluminum cup, dissolved in approximately 1 g of acetone, and then allowed to air dry at room temperature. The solution was then dried at 140°C for 3 hours using a hot air dryer (manufactured by Espec Corporation, product name "PHH-101"), cooled in a desiccator, and the mass was measured. The solids concentration (non-volatile content) of the polymer solution was calculated from the mass loss. The range of weight loss on heat of the radical polymerizable polymer is preferably 0 to 5%, more preferably 0 to 3%, even more preferably 0 to 2.5%, particularly preferably 0 to 2.1%, particularly more preferably 0 to 1.5%, and most preferably 0 to 1.0%. When the weight loss on heat is within the above range, thermal decomposition resistance is increased. As a method for polymerizing the above-mentioned monomer components, commonly used techniques such as bulk polymerization, solution polymerization, emulsion polymerization, etc. can be used, and may be appropriately selected depending on the purpose and application. Among them, solution polymerization is preferred because it is industrially advantageous and allows easy structural adjustment such as molecular weight. Furthermore, as a polymerization mechanism for the above-mentioned monomer components, polymerization methods based on mechanisms such as radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization can be used, but polymerization methods based on a radical polymerization mechanism are preferred because they are industrially advantageous. The polymerization initiation method for the above polymerization reaction can be achieved by supplying the energy required to initiate polymerization to the monomer components from an active energy source such as heat, electromagnetic waves (infrared rays, ultraviolet rays, X-rays, etc.), or electron beams, and the use of a polymerization initiator in combination is preferable because it can significantly reduce the energy required to initiate polymerization and also 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 polymerization initiator, the polymerization temperature, the type and amount of chain transfer agent, etc. When the above-mentioned monomer components are polymerized by a solution polymerization method, the solvent used for the 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 monomers 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. 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 acetate glycol monoether esters 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, propylene glycol monomethyl ether acetate and isopropanol are more preferable in terms of the solubility of the resulting polymer, transparency, and the action as a chain transfer agent. 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 polymerizing the monomer components, a commonly used polymerization initiator may be added, as described above. The polymerization initiator is not particularly limited, but examples include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, 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 polymerization initiators may be used alone or in combination of two or more. The amount of initiator used is not particularly limited and may be appropriately determined depending on the combination of monomers used, reaction conditions, the molecular weight of the target polymer, etc., but it is preferable to use 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, of the total monomer components, since this allows for the production of a polymer with a weight-average molecular weight of several thousand to several tens of thousands without gelation.

[0014] When polymerizing the monomer components, a commonly used chain transfer agent may be added as needed to adjust the molecular weight. Examples of chain transfer agents 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. Preferred are n-dodecyl mercaptan and mercaptopropionic acid, which have a high chain transfer effect, can reduce residual monomers, and are readily available. When a chain transfer agent is used, its amount is not particularly limited and can be appropriately determined depending on the combination of monomers used, reaction conditions, and the molecular weight of the target polymer. However, a preferred amount is 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, of the total monomer components, since this allows for the production of polymers with weight-average molecular weights 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 the thiol 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 it is particularly preferable that the polymer is substantially free of the thiol chain transfer agent. The polymerization method is not particularly limited, and may include a method in which all of the monomer components are charged into 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 polymerized, etc. For 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 elevated pressure. The temperature during the polymerization reaction varies depending 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 solvent and each monomer component so that the final solids concentration of the polymer solution is 10 to 70% by mass. From the viewpoints of productivity and polymerizability, the final solids concentration is more preferably 20 to 65% by mass, and even more preferably 25 to 60% by mass. After the polymerization step, for example, an epoxy group-containing monomer is subjected to an addition reaction with a portion of the acid groups contained in the base polymer. This reaction method is not particularly limited, and any known method may be appropriately employed. However, for example, the reaction temperature is preferably set to 60 to 140°C. It is also preferable to use known catalysts such as amine compounds such as triethylamine and dimethylbenzylamine; ammonium salts such as tetraethylammonium chloride; phosphonium salts such as tetraphenylphosphonium bromide; and amide compounds such as dimethylformamide. The amount of the epoxy group-containing monomer used is preferably set appropriately so that the acid value and double bond equivalent are within the desired ranges, but for example, it is preferably 1 to 90 parts by mass per 100 parts by mass of the total amount of the monomer components that give the base polymer. This further improves adhesion, enhances curability, and provides a cured product with even more sufficient strength. It is more preferably 3 to 85 parts by mass, even more preferably 5 to 80 parts by mass, and most preferably 5 to 60 parts by mass. The amount of the epoxy group-containing monomer used is preferably 10 to 95 mol %, more preferably 15 to 90 mol %, and even more preferably 20 to 85 mol %, relative to 100 mol % of the acid group-containing monomer in the monomer component that gives the base polymer. In the case of a polymer (base polymer) obtained by polymerizing a monomer component containing an epoxy group-containing monomer, a radically polymerizable polymer having a polymerizable double bond in its side chain can be obtained by reacting an acid group-containing monomer (an unsaturated monomer having an acid group) with the epoxy group of the base polymer. This reaction method is not particularly limited, but it is preferable to set the reaction temperature at 60°C to 140°C. It is also preferable to use known catalysts such as amine compounds such as triethylamine and dimethylbenzylamine; ammonium salts such as tetraethylammonium chloride; phosphonium salts such as tetraphenylphosphonium bromide; and amide compounds such as dimethylformamide. The amount of the acid group-containing monomer used is preferably 1 to 60 parts by mass per 100 parts by mass of the total amount of the monomer components that give the base polymer. This further improves adhesion, enhances curability, and ensures sufficient strength of the cured product. The amount is more preferably 2 to 50 parts by mass, and even more preferably 3 to 40 parts by mass. It is also preferable to react a polybasic acid anhydride after the addition reaction of the acid group-containing monomer. In this reaction, the hydroxyl group generated by the reaction of the epoxy group contained in the base polymer with the acid group-containing monomer is reacted with the polybasic acid anhydride to generate a carboxyl group. By performing this reaction, the acid value can be adjusted to an appropriate level. The polybasic acid anhydride is not particularly limited, and examples thereof include dibasic acid anhydrides such as succinic anhydride (also known as succinic anhydride), maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, and itaconic anhydride; trimellitic anhydride; and the like. The amount of the polybasic acid anhydride used is not particularly limited, but is preferably set so that the acid value of the resulting radically polymerizable polymer falls within the above-mentioned range. During synthesis, the amounts of the solvent and each monomer component are preferably set so that the final solid concentration of the radically polymerizable polymer solution is 10 to 70% by mass. From the viewpoints of productivity and polymerizability, the final solid concentration (non-volatile content) is more preferably 20 to 65% by mass, and even more preferably 25 to 60% by mass. The present invention also provides a photosensitive resin composition containing the above-mentioned radical polymerizable polymer, a polyfunctional monomer, a photopolymerization initiator, inorganic fine particles, and a solvent. A negative photosensitive resin composition is particularly preferred. Applications are not limited, but the composition is suitable for use as a material for forming protective films for color filters, liquid crystal display devices, integrated circuit devices, solid-state imaging devices, and the like. In the photosensitive resin composition, the content of the radical polymerizable polymer is preferably 5% by mass or more and suitably 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. The content is more preferably 10 to 65% by mass, even more preferably 10 to 50% by mass, particularly preferably 10 to 45% by mass, and most preferably 15 to 40% by mass.

[0015] 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 with active energy rays such as free radicals, electromagnetic waves (e.g., infrared rays, ultraviolet rays, X-rays, etc.), and electron beams. Examples include polyfunctional compounds having two or more polymerizable unsaturated groups in the molecule. While the molecular weight is not particularly limited, from the viewpoint of ease of handling, it is preferably 3,000 or less, and more preferably 2,000 or less. Among these, bifunctional or higher polyfunctional (meth)acrylate compounds (hereinafter simply referred to as "polyfunctional (meth)acrylate compounds") are particularly preferred. These compounds have two or more (meth)acryloyl groups in one molecule. The inclusion of such compounds imparts excellent photosensitivity and curability to the photosensitive resin composition, enabling the production of a cured film with extremely high hardness and transparency. The number of functionalities of the polyfunctional (meth)acrylate compound is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. In addition, 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. The content of the polyfunctional monomer may be appropriately set depending on the type of polyfunctional monomer and the radically polymerizable polymer used, as well as the purpose and application, but from the viewpoint of superior developability and plate-making properties, it is preferably 2% by mass or more and suitably 85% by mass or less, relative to 100% by mass of the total solids 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 to 500 parts by mass relative to 100 parts by mass of the radical polymerizable polymer. A polyfunctional monomer content within this range not only provides a cured film with higher surface hardness, but also, combined with the preferred weight-average molecular weight of the radical polymerizable polymer being 3,000 or greater, improves developability. The content is more preferably 80 parts by mass or greater, even more preferably 100 parts by mass or greater, and particularly preferably 120 parts by mass or greater. From the viewpoint of further improving developability, the content is more preferably 400 parts by mass or less. The content is even more preferably 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 photo or thermal 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-hydroxycyclohexylphenyl 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-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone, 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, methyl o-benzoylbenzoate, 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 the thioxanthones include 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride, as well as phenylglyoxylic methyl ester, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.Among these, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone are preferred.

[0016] Examples of the photopolymerization initiator include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, 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.

[0017] 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 referred to as an aminoketone polymerization initiator). That is, it is preferable that the photosensitive resin composition further contains an aminoketone polymerization initiator. This results in better hardness and heat resistance. The content of the photopolymerization initiator may be appropriately set depending on the purpose, application, 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 allows for the production of a cured film with superior heat resistance. The content is more preferably 1 part by mass or more, and even more preferably 1.2 parts by mass or more. Furthermore, taking into consideration the balance between the effects of decomposition products of the photopolymerization initiator and economic efficiency, the content is preferably 30 parts by mass or less. The content is more preferably 20 parts by mass or less, even more preferably 10 parts by mass or less, and most preferably 5 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.

[0018] As inorganic fine particles, in addition to silicon oxides such as silica described above, metal oxides such as titanium oxide, aluminum oxide, and zirconium oxide (zirconia, etc.); and metal salts such as calcium carbonate and barium sulfate are preferred. Among these, metal oxides are more preferred. Composite metal oxides containing two or more types of metal atoms are also suitable. Metal oxide particles having hydroxyl groups on the surface are more preferred, and silica particles are particularly preferred. Of these, surface-modified silica fine particles are preferred, and for example, those surface-modified with (meth)acryloyloxy groups bonded to silicon atoms via a divalent linking group are even more preferred. The silica microparticles 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 cyclic ether structure with five or more members, which is 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 with 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, 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 used in the form of a dried powder or a dispersion (e.g., colloidal silica) dispersed in an organic solvent. However, from the viewpoint of the dispersion stability of the photosensitive resin composition, it is preferable to use a dispersion 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 particle shapes include spherical, granular, ellipsoidal, cubic, rectangular, pyramidal, needle-like, columnar, rod-like, cylindrical, scale-like, plate-like, and thin flake-like shapes. Considering dispersibility in the solvent, spherical, granular, and columnar shapes are preferred. Specific examples of organic solvents include the various solvents described in JP 2013-227485 A (Patent Publication No. 2013-227485). 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 JP 2013-227485 A (

[0026] ) (e.g., NBAC-ST (organosilica sol using 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 10% by mass or more, and even more preferably 15% by mass or more, based on 100% by mass of the total solid content of the photosensitive resin composition. Furthermore, from the viewpoints of developability, transparency, etc., the content is preferably 50% by mass or less, and more preferably 40% by mass or less. When at least a silicon-containing compound (preferably silica fine particles) is used as the inorganic fine particles, the content (solid content) thereof 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, per 100 parts by mass of the total amount of inorganic fine particles in the photosensitive resin composition. The photosensitive resin composition (preferably a negative-type 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 components such as the polymer, polyfunctional monomer, photopolymerization initiator, and inorganic fine particles. Specific examples include 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. The content of the solvent may be appropriately determined depending on the optimal viscosity of the photosensitive resin composition when used. For example, the amount is 1,200 parts by mass or less, more preferably 900 parts by mass or less, per 100 parts by mass of the polymer. The lower limit is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, per 100 parts by mass of the polymer. By controlling the amount within the above range, the handleability and storage stability of the composition, as well as the efficiency of the coating operation, are improved. The viscosity of the photosensitive resin composition can be appropriately set depending on 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 a photosensitive resin composition in which the solid content (non-volatile content) is adjusted to 40% 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, handleability and coating workability are improved.

[0019] 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, antifoaming agents, coupling agents, leveling agents, sensitizers, mold release agents, lubricants, plasticizers, antioxidants, UV absorbers, light stabilizers, flame retardants, polymerization inhibitors, polymerization retarders, polymerization accelerators, thickeners, dispersants, and surfactants, provided that the effects of the present invention are not impaired. 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.

[0020] The method for preparing the photosensitive resin composition is not particularly limited and may be a known method, for example, a method in which the above-mentioned components are mixed and dispersed using various mixers or dispersers. The mixing and dispersion step is not particularly limited and may be performed by a known method. The composition may further include other commonly performed steps. When the photosensitive resin composition contains a colorant, it is preferable to prepare the composition via a colorant dispersion step. The colorant dispersion step may involve, for example, first weighing out predetermined amounts of colorant (preferably an organic pigment), dispersant, and solvent, and then dispersing the colorant into fine particles using a disperser to obtain a liquid colorant dispersion (also referred to as a "mill base"). Examples of such dispersers include paint conditioners, bead mills, roll mills, ball mills, jet mills, homogenizers, kneaders, and blenders. The dispersion step preferably involves kneading and dispersing the mixture using a roll mill, kneader, blender, or the like, followed by fine dispersion using a media mill, such as a bead mill filled with beads of 0.01 to 1 mm. A composition (preferably a transparent liquid) containing the radical polymerizable polymer and inorganic fine particles, which has been separately stirred and mixed, is added to the obtained mill base, and mixed to obtain a uniform dispersion solution, thereby obtaining a photosensitive resin composition. The obtained photosensitive resin composition is preferably filtered using a filter or the like to remove fine particles. The present invention also relates to a cured film obtained by curing the radically polymerizable polymer and / or the photosensitive resin composition. Materials used as substrates to which the film is applied include, for example, transparent materials such as glass, acrylic resin, polycarbonate resin, polyester resin such as PET, and polystyrene resin, as well as 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 allows sufficient fulfillment of the demand for low-profile components and displays using the cured film. The 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, and 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 preferably has high transparency. This allows, for example, a laminate including the cured film to be used in a touch panel, whereby the display performance is not impaired and a clear image can be displayed. The present invention also includes a laminate (for example, a color filter) having a cured product (cured film) of the photosensitive resin composition on a substrate. The color filter will be described below. The color filter of the present invention has a configuration in which a substrate is provided with a cured product of the photosensitive resin composition. In the color filter, the cured product formed from the photosensitive resin composition is particularly suitable for segments that require coloring, such as a black matrix or pixels of red, green, blue, yellow, etc., but is also suitable for segments that do not necessarily require coloring, such as photospacers, protective layers, and alignment control ribs. Substrates used in the color filters include, for example, glass substrates such as white plate glass, blue plate glass, alkali-strengthened glass, and silica-coated blue plate glass; sheets, films, or substrates made of thermoplastic resins such as polyester, polycarbonate, polyolefin, polysulfone, ring-opening polymers of cyclic olefins, and hydrogenated products thereof; sheets, films, or substrates made of thermosetting resins such as epoxy resins and unsaturated polyester resins; metal substrates such as aluminum plates, copper plates, nickel plates, and stainless steel plates; ceramic substrates; semiconductor substrates having photoelectric conversion elements; and components made of various materials such as glass substrates having a colorant layer on their surface (e.g., LCD color filters). Among these, glass substrates and sheets, films, or substrates made of heat-resistant resins are preferred in terms of heat resistance. It is also preferable that the substrate be transparent. The substrate may be subjected to corona discharge treatment, ozone treatment, chemical treatment with a silane coupling agent, or the like, as needed. To obtain the color filter, for example, it is preferable to employ a manufacturing method that includes, for each pixel color (i.e., for each pixel color), a step of disposing the photosensitive resin composition on a substrate (also referred to as a disposing step), a step of irradiating the photosensitive resin composition disposed on the substrate with light (also referred to as a light irradiation step), a step of developing with a developer (also referred to as a developing step), and a step of heat treatment (also referred to as a heat treatment step), and that repeats this same procedure for each color. Note that the order in which the pixels of each color are formed is not particularly limited. The above-mentioned disposing step is preferably carried out by coating. Examples of a method for coating the above-mentioned photosensitive resin composition on a substrate include spin coating, slit coating, roll coating, and cast coating. Since the viscosity of the photosensitive resin composition of the present invention can be adjusted within an appropriate range and is excellent in coating workability, any of these methods can be preferably used. The heating step is a final step (also referred to as a post-curing step) in which the exposed area (cured area) is further cured by baking. For example, a light source such as a high-pressure mercury lamp is used, and the cured area is further cured by baking at a luminous energy of, for example, 0.5 to 5 J / cm. 2 and a step of post-heating at a temperature of, for example, 60 to 260° C. for 10 seconds to 120 minutes. By carrying out such a post-curing step, it is possible to further increase the hardness and adhesion of the patterned cured film. As described above, the radical polymerizable polymer of the present invention has good handleability and excellent coating workability, and can give a cured product that is excellent in transparency and adhesion. Furthermore, the photosensitive resin composition containing the radical polymer of the present invention has excellent curability and can give a cured product that is excellent in adhesion to a substrate, transparency, heat resistance, etc. The surface hardness of the cured film is high because the photosensitive resin composition is cured. This allows the film to absorb external impacts even when used as a component of a protective film, insulating film, etc. In pencil hardness evaluation, the hardness decreases in the following order: 4H>3H>2H>H>F>HB>B>2B>3B>4B. The radical polymerizable polymer and photosensitive resin composition of the present invention are excellent in transparency, heat resistance (particularly thermal decomposition resistance), and coating workability, and can be used, for example, in applications such as resist materials, various coating agents, and paints. In addition, since the polymer contains 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, and the like. [Example]

[0021] 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 parts by mass, unless otherwise specified. In the following production examples, various physical properties were evaluated as follows. [Evaluation method] (1) Weight average molecular weight: Mw Measurement was carried out by GPC (HLC-8220GPC, manufactured by Tosoh Corporation) using THF as an eluent and a TSKgel SuperHZM-N (manufactured by Tosoh Corporation) column, and the values ​​were calculated in terms of standard polystyrene. (2) Solids Approximately 0.3 g of the copolymer solution prepared in the Production Example was weighed into an aluminum cup, dissolved in approximately 1 g of acetone, and then air-dried at room temperature. The solution was then dried at 140°C for 3 hours using a hot air dryer (product name: PHH-101, manufactured by Espec Corporation), cooled in a desiccator, and weighed. The weight of the solid content (resin) of the polymer solution was calculated from the weight loss. (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 carried out using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of polymer (mg KOH / g) was calculated from the solid concentration. (4) Thermogravimetric reduction A solution of 2 g of the copolymer solution prepared in Production Example and 4 g of tetrahydrofuran was added dropwise to 60 g of hexane, and the precipitated acrylic resin was separated, removed, and vacuum dried overnight at 40° C. 10 mg of the resulting acrylic resin powder was weighed, and the weight loss rate was measured at 230° C. for 30 minutes under a nitrogen atmosphere using a thermogravimetric analyzer TGA-50 (manufactured by SHIMADZU). [Production of radically polymerizable polymer] The following radical polymerizable polymers were used. [Manufacturing Example 1] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition containing 15 g of N-phenylmaleimide (PMI), 37 g of methacrylic acid (MAA), 10 g of tetrafurfuryl acrylate (THFA), 28 g of cyclohexyl methacrylate (CHMA), 10 g of 2-hydroxyethyl methacrylate (HEMA), and 8 g of t-butylperoxy-2-ethylhexanoate (trade name "Perbutyl (registered trademark) O", manufactured by NOF Corporation, hereinafter also referred to as PBO) was added to a monomer dropping vessel and mixed with stirring.

[0022] A reactor was charged with 233 g of propylene glycol methyl ether acetate (PGMEA), and the atmosphere was replaced with nitrogen. The reactor was then heated in an oil bath with stirring to 90°C. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of glycidyl methacrylate (GMA), 0.2 g of Antage W-400 (Kawaguchi Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.4 g of triphenylphosphine (TPP) as a catalyst were added to the reactor, 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 number-average molecular weight (Mn) of 3030, a weight-average molecular weight (Mw) of 8700, a molecular weight distribution (Mw / Mn) of 2.87, and an acid value of 85 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 2] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition consisting of 15 g of PMI, 37 g of MAA, 10 g of tetrafurfuryl methacrylate (THFMA), 28 g of methyl methacrylate (MMA), 10 g of HEMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0023] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-2) containing 36.5 wt% of resin. The resin had a number average molecular weight (Mn) of 2900, a weight average molecular weight (Mw) of 9000, a molecular weight distribution (Mw / Mn) of 3.10, and an acid value of 86 mgKOH / g. The production conditions, solid content, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 3] A separable flask equipped with a condenser was prepared as a reaction vessel. On the other hand, a monomer composition consisting of 15 g of PMI, 37 g of MAA, 10 g of (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate ("MEDOL10" manufactured by Osaka Organic Chemical Industry Co., Ltd.), 28 g of vinyltoluene (VT), 10 g of HEMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0024] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-3) containing 36.1 wt% resin. The resin had a number average molecular weight (Mn) of 2690, a weight average molecular weight (Mw) of 8600, Mw / Mn of 3.20, and an acid value of 85 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 4] A separable flask equipped with a condenser was prepared as a reaction vessel. On the other hand, a monomer composition consisting of 15 g of methyl (α-allyloxymethyl)acrylate (AOMA), 37 g of MAA, 10 g of THFA, 28 g of CHMA, 10 g of HEMA, and 10 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0025] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 17 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 7 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-4) containing 33.5 wt% resin. The resin had a number average molecular weight (Mn) of 2680, a weight average molecular weight (Mw) of 5500, Mw / Mn of 2.05, and an acid value of 150 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 5] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition consisting of 15 g of dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate (MD), 33 g of MAA, 10 g of MEDOL10, 10 g of HEMA, 32 g of MMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0026] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the reactor temperature 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 addition was complete, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 38 g of Cyclomer M100 (manufactured by Daicel, hereinafter referred to as M100), 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 21 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-5) containing 37.1 wt% resin. The resin had a number average molecular weight (Mn) of 3560, a weight average molecular weight (Mw) of 8000, Mw / Mn of 2.25, and an acid value of 88 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 6] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition of 15 g of PMI, 47 g of MAA, 10 g of THFMA, 10 g of HEMA, 18 g of CHMA, and 10 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0027] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 58 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 21 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-6) containing 40.5 wt% resin. The resin had a number average molecular weight (Mn) of 3120, a weight average molecular weight (Mw) of 11000, Mw / Mn of 3.53, and an acid value of 50 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 7] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition of 30 g of PMI, 37 g of MAA, 10 g of THFMA, 10 g of HEMA, 13 g of CHMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0028] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-7) containing 36.7 wt% resin. The resin had a number average molecular weight (Mn) of 3050, a weight average molecular weight (Mw) of 9100, Mw / Mn of 2.98, and an acid value of 85 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 8] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition of 15 g of PMI, 37 g of MAA, 10 g of THFA, 38 g of CHMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0029] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-8) containing 36.0 wt% resin. The resin had a number average molecular weight (Mn) of 3280, a weight average molecular weight (Mw) of 8200, Mw / Mn of 2.50, and an acid value of 84 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 9] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition of 15 g of PMI, 37 g of MAA, 10 g of THFA, 10 g of HEMA, 28 g of CHMA, and 2 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0030] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-9) containing 36.8 wt% resin. The resin had a number average molecular weight (Mn) of 5,850, a weight average molecular weight (Mw) of 20,000, Mw / Mn of 3.42, and an acid value of 85 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 10] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition of 15 g of PMI, 37 g of MAA, 10 g of VT, 10 g of HEMA, 28 g of CHMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0031] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the temperature of the reactor 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 addition was completed, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-10) containing 36.2 wt% resin. The resin had a number average molecular weight (Mn) of 3350, a weight average molecular weight (Mw) of 8800, Mw / Mn of 2.63, and an acid value of 86 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 11] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition consisting of 15 g of PMI, 15 g of MAA, 10 g of MEDOL10, 22 g of VT, 10 g of HEMA, 28 g of CHMA, and 6 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0032] A reactor was charged with 233 g of PGMEA and purged with nitrogen. The reactor was then heated in an oil bath with stirring to 90°C. After the reactor temperature 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 addition was complete, 0.5 g of PBO was added. After an additional 30 minutes, the reactor was heated to 115°C. After maintaining the temperature at 115°C for 1 hour, the mixture was cooled to room temperature to obtain a copolymer solution (A-11) containing 30.3 wt% of resin. The resin had a number-average molecular weight (Mn) of 2940, a weight-average molecular weight (Mw) of 6200, a Mw / Mn ratio of 2.11, and an acid value of 100 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. [Manufacturing Example 12] A separable flask equipped with a condenser was prepared as a reaction vessel. A monomer composition consisting of 37 g of MAA, 10 g of THFMA, 15 g of MMA, 10 g of HEMA, 28 g of CHMA, and 8 g of PBO was added to a monomer dropping vessel and mixed with stirring.

[0033] 233 g of PGMEA was charged into the reactor, and the atmosphere was replaced with nitrogen. The reactor temperature was then raised to 90°C by stirring in an oil bath. After the reactor temperature 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 addition was complete, 0.5 g of PBO was added. After an additional 30 minutes, the reactor 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 7 / 93 (v / v) oxygen / nitrogen mixed gas began. Next, 33 g of GMA, 0.2 g of Antage W-400 as a polymerization inhibitor, and 0.4 g of TPP as a catalyst were charged into the reactor, and the reaction was carried out at 115°C for 14 hours. The mixture was then cooled to room temperature, yielding a copolymer solution (A-12) containing 36.3 wt% resin. The resin had a number average molecular weight (Mn) of 3620, a weight average molecular weight (Mw) of 8800, Mw / Mn of 2.43, and an acid value of 86 mgKOH / g. The production conditions, solids concentration, Mn, Mw, Mw / Mn, and acid value of the copolymer solution are shown in Table 1, along with those of Production Examples 2 to 12. Table 1 shows the compositions and physical properties of the above radical polymerizable polymers A-1 to A-8 (Examples 1 to 8) and A-9 to A-12 (Comparative Examples 1 to 4).

[0034] [Table 1] [Preparation of Photosensitive Resin Composition] 3.31 g of the copolymer solution (A-1) (i.e., 1.2 g of resin) was used as the binder resin, 4.00 g of PGM-AC-4130Y (1.2 g of nonvolatile content: manufactured by Nissan Chemical Industries, Ltd.) was used as inorganic fine particles, 1.54 g of DPHA was used 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 Ltd., hereinafter referred to as Irg907) was used as a photopolymerization initiator. The mixture was diluted with PGMEA to a nonvolatile content concentration of 40 wt %, thereby preparing photosensitive resin composition B1. Similarly, photosensitive resin compositions B2 to B12 were prepared using the copolymer solutions (A-2 to A-12) as the binder resin. 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' x R24). <Curing method> The photosensitive resin compositions B1 to B12 were applied to a 5 cm square glass substrate using a spin coater and dried in an oven at 80°C for 3 minutes. After drying, the photosensitive resin compositions were applied at 1 J / cm using a UV aligner (trade name "TME-150RNS", manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp. 2 The coatings were irradiated with ultraviolet light at an intensity of 1000 kJ / cm² (equivalent to 365 nm illuminance). After ultraviolet irradiation, the coatings were post-cured at 160°C for 1 hour to completely cure. All of the resulting coatings were transparent, and were therefore subjected to the following evaluations (5) and (6). The results are shown in Table 2. (5) Adhesion (cross-cut test) According to JIS K5600-5-6:1999 "General test methods for paints - Part 5: Mechanical properties of coating films - Section 6: Adhesion (cross-cut method)", the remaining film rate was rated as 1 if it was 100-90%, 2 if it was 89-80%, 3 if it was 79-70%, 4 if it was 69-60%, and 5 if it was less than 59%. The evaluation results are shown in Table 2. (6) 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 any marks was used as the hardness (surface hardness) value.

[0035] [Table 2] 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 radically polymerizable polymer of the present invention. Specifically, polymers containing specific structural units and having a weight-average molecular weight of 19,000 or less exhibited low viscosity in the composition, favorable handleability, small thermal weight loss, and high thermal decomposition resistance. In particular, Comparative Example 4 (Polymer A-12) does not contain structural units with a cyclic structure in the main chain, and therefore is presumed to have significantly lower thermal decomposition resistance than other polymers. Furthermore, the composition containing Comparative Example 2 (Polymer A-10), which does not contain structural units derived from unsaturated monomers having a cyclic ether structure of five or more members, exhibited high viscosity. Furthermore, compositions containing Examples 1 and 4 (Polymers A-1 and A-4), which contain HEMA, tended to have slightly lower viscosity than the composition containing Example 8 (Polymer A-8), which does not contain HEMA. Polymers containing structural units derived from unsaturated monomers having a cyclic ether structure of five or more members or hydroxyl group-containing monomers are thought to have high affinity with inorganic fine particles and thus improve dispersibility. 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 9 to 16 had low viscosity and excellent coating workability. In particular, comparison with Comparative Examples 5 and 6 suggests that the molecular weight of the polymer contained therein and the structural units derived from the unsaturated monomer having a cyclic ether structure with a five- or greater ring are effective in reducing viscosity. Furthermore, although not shown in the table, the resulting cured film has high transparency, making it suitable for use in the optical field. Furthermore, the pencil hardness of the cured film obtained from the composition of Example 11 was higher than that of Comparative Example 7, which is likely due to the polymerizable double bond provided to the side chain of the polymer contained in the composition. Furthermore, the composition of Example 15, which contained Polymer A-7 with a high PMI content, exhibited the best physical properties in terms of viscosity, adhesion, and pencil hardness. [Industrial Applicability]

[0036] The radical polymerizable polymer and photosensitive resin composition of the present invention can be applied to, for example, resist materials, and can be suitably used in the fields of optics and electric / electronics.

Claims

1. A photosensitive resin composition (excluding those containing quinophthalone pigment and halogenated zinc phthalocyanine pigment) comprising a radical polymerizable polymer having a weight average molecular weight of 19,000 or less, a polyfunctional monomer, a photopolymerization initiator, silica microparticles, and a solvent, the photosensitive resin composition comprising a structural unit derived from an unsaturated monomer having an acid group, a structural unit derived from an unsaturated monomer having a cyclic ether structure of five or more members, a structural unit having a ring structure in the main chain, and a polymer having a polymerizable double bond in the side chain, the weight average molecular weight of the polymer being 19,000 or less.

2. The photosensitive resin composition according to claim 1, wherein the radical polymerizable polymer has a double bond equivalent of 300 to 2000 (g / mol).

3. A photosensitive resin composition as described in claim 1 or 2, wherein the content of structural units having a ring structure in the main chain is 9 mass% or more relative to 100 mass% of all structural units of the radically polymerizable polymer.

4. A photosensitive resin composition described in any of claims 1 to 3, wherein the content of structural units derived from unsaturated monomers having a cyclic ether structure of five or more members is 7.5 mass% or more relative to 100 mass% of all structural units of the radically polymerizable polymer.

5. A photosensitive resin composition described in any one of claims 1 to 4, wherein the number average primary particle diameter of the silica microparticles is 1 to 200 nm.

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