Alkali-soluble resin, photosensitive resin composition, and cured product thereof

Abstract

The present invention provides: an alkali-soluble resin that can give highly solvent-resistant cured products even under low-temperature curing conditions and can be suitably used for various applications such as color filters; and a photosensitive resin composition containing said resin. The present invention pertains to an alkali-soluble resin having a specific structure of an epoxy group-containing structure, a carboxyl group-containing structure, and a polymerizable unsaturated bond-containing structure, and having an epoxy equivalent weight of 50000 g / eq or less.

Description

Alkali-soluble resin, photosensitive resin composition and cured product thereof

[0001] The present invention relates to an alkali-soluble resin and a photosensitive resin composition, and more particularly to an alkali-soluble resin and a photosensitive resin composition that can provide a cured product having excellent solvent resistance even under low-temperature curing conditions, and the cured product thereof.

[0002] Alkali-soluble resins are compounds used in a variety of fields, from civil engineering and construction to electronic information. Among these, alkali-soluble resins that are cured by irradiation with light or electron beams have the property of curing the portions irradiated with light or electron beams while remaining soluble in other portions. Taking advantage of this property, they are preferably used as materials for alkali-developable resist compositions (also referred to as photosensitive resin compositions). Such resist compositions are applied to, or are being considered for, various optical components and electrical / electronic devices, such as color filters, inks, printing plates, printed wiring boards, semiconductor elements, photoresists, organic insulating films, and organic protective films used in liquid crystal display devices and solid-state imaging devices. In recent years, optical components and electrical / electronic devices have become increasingly smaller, thinner, and more energy-efficient. This has led to demands for higher performance from the various components used in these devices. To meet these demands, research is being conducted on photosensitive resin compositions that can be used as materials for various components.

[0003] Various photosensitive resin compositions have been developed to date to meet desired characteristics. For example, Patent Document 1 discloses a photocurable resin composition containing a compound having an epoxy group, a photobase generator, a curing agent having a thiol group, a monomer having an unsaturated bond, and a radical generator that generates radicals upon irradiation with light. This photocurable resin composition has been discovered to be tack-free when formed into a coating film before exposure. Patent Document 2 also discloses a copolymer containing three types of (meth)acrylate repeating units, classified by the type of functional group present at the terminal, and having alkali-solubility, photocurability, and thermosetting properties, and a photosensitive resin composition using the copolymer. This copolymer has excellent thermosetting properties at relatively low temperatures and can also be photocured by irradiation with light, resulting in a patterned film with improved curing degree, durability, and chemical resistance.

[0004] Japanese Patent Application Laid-Open No. 2013-181991 Special Publication No. 2021-521310

[0005] As described above, various photosensitive resin compositions have been investigated to date. However, when conventional photosensitive resin compositions are used together with colorants as raw materials for color filters, for example, there is a problem of the colorants leaching from the raw materials into cleaning solvents during the production of color filters. Therefore, there is a need for further improvement in the solvent resistance of photosensitive resin compositions. In recent years, particularly in color filter applications, the improvement in quality and expansion of applications of color liquid crystal display devices and the like have led to a strong demand for higher performance, such as higher brightness and contrast, of display panels. However, in the production of color filters, if the baking process (post-curing process) after exposure and development is performed at a high temperature above 200°C, the resulting cured product will discolor, such as yellowing, preventing sufficient coloration of the desired color. Furthermore, if the baking process is performed at a high temperature, unwanted reactions will proceed, producing by-products that will degrade the properties of the substrate and the cured film. To suppress such unwanted reactions and efficiently obtain color filters with the desired properties, it is desirable for the curing reaction to proceed sufficiently even under relatively low heating conditions of 200°C or less. Furthermore, if the photosensitive resin composition can be cured at a relatively low temperature, the production efficiency of color filters can also be improved. The compositions described in Patent Documents 1 and 2 are insufficient in curability and solvent resistance, and there is room for improvement in these properties.

[0006] The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide an alkali-soluble resin that can give a cured product having excellent solvent resistance even under low-temperature curing conditions and that can be suitably used in various applications such as color filters, and a photosensitive resin composition containing the resin.

[0007] As a result of intensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using an alkali-soluble resin having a specific epoxy group-containing structure, a carboxyl group-containing structure, and a polymerizable unsaturated bond-containing structure and having an epoxy equivalent of 50,000 g / equivalent or less, and further by using a photosensitive resin composition containing such a specific alkali-soluble resin, a polymerizable compound, and a photopolymerization initiator, and have thus completed the present invention.

[0008] That is, the object of the present invention is achieved by the following <1> to <8>: <1> An alkali-soluble resin having at least one epoxy group-containing structure selected from the structure represented by the following formula (1) and the structure represented by the following formula (2), at least one carboxyl group-containing structure selected from the structures represented by the following formulas (3) to (4'), and at least one polymerizable unsaturated bond-containing structure selected from the structure represented by the following formula (5) and the structure represented by the following formula (5'), and having an epoxy equivalent of 50,000 g / equivalent or less.

[0009]

[0010] (In formulas (2), (3'), (4') and (5'), m is an integer from 1 to 10. In formulas (3) and (3'), R １ are the same or different and represent a divalent organic group. ２ and R ３ are the same or different and are a hydrogen atom or a group represented by formula (6), and R ２ At least one of R is a group represented by formula (6). ４ are the same or different and represent a trivalent organic group. ５ , R ６ and R ７ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. ８ , R ９ are the same or different and represent a direct bond or a divalent organic group. １０represents a divalent organic group.) <2> The alkali-soluble resin according to <1>, characterized in that it has an acid value of 30 to 200 mgKOH / g. <3> A photosensitive resin composition characterized in that it contains the alkali-soluble resin according to <1> or <2>, a polymerizable compound, and a photopolymerization initiator. <4> A cured product characterized in that it is obtained by curing the alkali-soluble resin according to <1> or <2>, or the photosensitive resin composition according to <3>. <5> A member for a display device, characterized in that it contains the cured product according to <4>. <6> A display device, characterized in that it contains the member for a display device according to <5>. <7> A method for producing an alkali-soluble resin, the method comprising: a first step of reacting an epoxy resin (a) having two or more epoxy groups per molecule with a monobasic acid (b) having a primary alcoholic hydroxyl group and an unsaturated monocarboxylic acid (c), and a second step of reacting the reaction product obtained in the first step with a polybasic acid anhydride (d), wherein the amounts of the monobasic acid (b) having a primary alcoholic hydroxyl group and the unsaturated monocarboxylic acid (c) used in the first step are adjusted so that the epoxy equivalent of the resulting alkali-soluble resin is 50,000 g / equivalent or less. <8> A method for producing a photosensitive resin composition, the method comprising: a step of producing an alkali-soluble resin by the method for producing an alkali-soluble resin according to <7>; and a step of mixing the resulting alkali-soluble resin having an epoxy equivalent of 50,000 g / equivalent or less, a polymerizable compound, and a photopolymerization initiator.

[0011] The alkali-soluble resin and photosensitive resin composition of the present invention can provide a cured product having excellent solvent resistance even under relatively low-temperature curing conditions. The cured product of the present invention can be suitably used for various applications, such as various optical components used in liquid crystal, organic EL, quantum dot, and micro LED liquid crystal displays, solid-state imaging devices, touch panel display devices, etc., and components of electrical and electronic devices.

[0012] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to the following description and can be appropriately modified and applied within the scope that does not change the gist of the present invention. It should be noted that embodiments combining two or more of the individual preferred embodiments of the present invention described below also fall within preferred embodiments of the present invention. In this specification, "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid," and "(meth)acrylate" means "acrylate and / or methacrylate." Furthermore, in this specification, the numerical range "Min to Max" means not less than the minimum value Min and not more than the maximum value Max. Furthermore, when preferred numerical values ​​are described in stages for the upper and lower limit values, a numerical range obtained by appropriately combining the separately described upper and lower limit values ​​is also a preferred numerical range.

[0013] 1. Alkali-Soluble Resin The alkali-soluble resin of the present invention is a resin having, in a polymer side chain, at least one epoxy group-containing structure selected from the structure represented by the above formula (1) and the structure represented by the above formula (2), at least one carboxyl group-containing structure selected from the structures represented by the above formulas (3) to (4'), and at least one polymerizable unsaturated bond-containing structure selected from the structure represented by the above formula (5) and the structure represented by the above formula (5'), and having an epoxy equivalent of 50,000 g / equivalent or less.

[0014] When the alkali-soluble resin of the present invention is used as a resist material, the polymerizable unsaturated bonds react upon exposure to light, hardening the exposed areas, and then baking treatment causes the epoxy groups and carboxyl groups to react, resulting in post-curing. The alkali-soluble resin of the present invention has excellent alkaline developability due to the presence of carboxyl groups at positions spaced apart from the main chain. Furthermore, since the carboxyl groups at positions spaced apart from the main chain have good reactivity with epoxy groups, the reaction with the epoxy groups proceeds smoothly during post-curing even under curing conditions at relatively low temperatures (e.g., 160°C or lower), resulting in a cured product with excellent solvent resistance.

[0015] The alkali-soluble resin of the present invention has at least one epoxy group-containing structure selected from the structure represented by formula (1) above and the structure represented by formula (2) above. m in formula (2) above is an integer of 1 to 10, preferably 2 to 8, and more preferably 3 to 6. The same applies to m in formulas (3'), (4'), and (5') above.

[0016] The alkali-soluble resin of the present invention has at least one carboxyl group-containing structure selected from the structures represented by the above formulas (3) to (4') (i.e., the above formulas (3), (3'), (4) and (4')). １ are the same or different and represent a divalent organic group, and the divalent organic group is a group represented by the following formula (7):

[0017]

[0018] (In formula (7), R １１ represents a divalent hydrocarbon group which may have a substituent. １２ represents any structure of formula (8) or a direct bond. １１ The hydrocarbon group in is preferably a hydrocarbon group having 1 to 12 carbon atoms. More preferably, it is a hydrocarbon group having 1 to 10 carbon atoms. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The hydrocarbon group may have a chain structure, a cyclic structure, or a structure having both a chain portion and a cyclic portion. When the hydrocarbon group has a cyclic structure, the cyclic structure may be an alicyclic structure or an aromatic ring. Furthermore, R １１ Examples of the substituent in include a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom, and a cyano group.

[0019] R in the above formula (7) １１ As for R １２ The carboxyl group-containing structure represented by formula (3) or (3′) is preferably a structure in which the terminals on the opposite side to the R ２ is preferably a structure represented by formula (6). That is, the terminal —R １ -O-R２ is expressed by the following formula (9):

[0020]

[0021] (In formula (9), R １１ R' represents a hydrocarbon group having 1 to 11 carbon atoms or a direct bond. １２ is the same as equation (7). １０ is the same as formula (6). A structure represented by formula (3) or (3') is one of the preferred embodiments of the carboxyl group-containing structure represented by formula (3). This structure will be described later in "2. Method for producing alkali-soluble resin."

[0022] R in formulas (3) to (4′) ２ and R ３ are the same or different and are a hydrogen atom or a group represented by the above formula (6), and R ２ In other words, when the alkali-soluble resin of the present invention has only the structure represented by the formula (3) or only the structure represented by the formula (3') as a carboxyl group-containing structure, R ２ is a group represented by formula (6), and when the alkali-soluble resin has a structure represented by formula (3) and a structure represented by formula (3'), R ２ is a group represented by formula (6). When the alkali-soluble resin has only the structure represented by formula (4) or only the structure represented by formula (4') as a carboxyl group-containing structure, two R ２ is a group represented by formula (6), and when the alkali-soluble resin has a structure represented by formula (4) and a structure represented by formula (4'), four R ２When the alkali-soluble resin has the structure represented by the formula (3) and / or the structure represented by the formula (3′) as a carboxyl group-containing structure, and the structure represented by the formula (4) and / or the structure represented by the formula (4′), at least one of R present in the structure represented by the formula (3) and / or the structure represented by the formula (3′) of the alkali-soluble resin is a group represented by the formula (6). ２ and R present in formula (4) and / or (4′). ２ In any of formulas (3) to (4′), one or more of R ３ may be a hydrogen atom or a group represented by formula (6).

[0023] R in the above formula (4) and formula (4′) ４ represents a trivalent organic group, and the trivalent organic group is represented by the following formula (10):

[0024]

[0025] (In formula (10), R １３ represents a trivalent hydrocarbon group which may have a substituent. １４ represents any of the structures of the above formula (8) or a direct bond. p and q are the same or different and each represents an integer of 0 to 3. In one preferred embodiment of the present invention, R is a group represented by the formula (8). １３ The hydrocarbon group is preferably a hydrocarbon group having 1 to 10 carbon atoms. More preferably, it is a hydrocarbon group having 1 to 6 carbon atoms. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The hydrocarbon group may have a chain structure, a cyclic structure, or a structure having both a chain portion and a cyclic portion. The cyclic structure may be an alicyclic structure or an aromatic ring. R １３ The substituents in the hydrocarbon group of R １１ The substituents for the hydrocarbon group are the same as those for the hydrocarbon group.

[0026] One of the preferred forms of the structure represented by the above formula (10) is the following formula (11):

[0027]

[0028] (In formula (11), R １５ represents a hydrogen atom or a monovalent hydrocarbon group which may have a substituent. １４ , p, and q are the same as those in formula (10). １５ The monovalent hydrocarbon group is preferably a hydrocarbon group having 1 to 7 carbon atoms. More preferably, it is a hydrocarbon group having 1 to 3 carbon atoms. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The hydrocarbon group may have a chain structure, a cyclic structure, or a structure having both a chain portion and a cyclic portion. The cyclic structure may be an alicyclic structure or an aromatic ring. R １５ The substituents in the hydrocarbon group of R １１ The substituents for the hydrocarbon group are the same as those for the hydrocarbon group.

[0029] The carboxyl group-containing structure represented by the above formula (4) or (4′) includes R ４ is a structure represented by the above formula (10), in which either p or q is 1 or more, and the subsequent R ２ is preferably a structure represented by formula (6). That is, R in the structure represented by formula (4) or formula (4') is preferably ４ The subsequent terminal structure is the following formula (12):

[0030]

[0031] (In formula (12), R ２ is the same as in formulas (3) to (4'). １０ is the same as equation (6). １３ , R １４ is the same as formula (10). p is a number of 1 or more, and q is a number of 0 or more. A structure represented by formula (4) or formula (4') is one of preferred embodiments of the carboxyl group-containing structure represented by formula (4). This structure will be described later in "2. Method for producing alkali-soluble resin."

[0032] The alkali-soluble resin of the present invention further has at least one polymerizable unsaturated bond-containing structure selected from the structure represented by the above formula (5) and the structure represented by formula (5′).３ may be a hydrogen atom or a group represented by formula (6). ５ , R ６ and R ７ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. Examples of the hydrocarbon group having 1 to 6 carbon atoms include linear or cyclic hydrocarbon groups having 1 to 6 carbon atoms, with linear hydrocarbon groups having 1 to 6 carbon atoms being preferred, and alkyl groups having 1 to 6 carbon atoms being more preferred. Among these, R ５ , R ６ and R ７ are preferably the same or different and each is a hydrogen atom or a methyl group, and R ５ , R ６ is a hydrogen atom, and R ７ It is more preferable that R in formula (5) and formula (5′) is a hydrogen atom or a methyl group. ８ , R ９ are the same or different and represent a direct bond or a divalent organic group. The divalent organic group may be a hydrocarbon group having 1 to 12 carbon atoms, -O-, -CO-, -NH-, -S-, -SO-, or -SO ２ -, etc., and those having a substituent bonded thereto. １１ The substituents may be the same as those that the hydrocarbon group may have.

[0033] R in the above formula (6) １０ is a divalent organic group. The divalent organic group is R ８ , R ９ The divalent organic groups include the same as those mentioned above.

[0034] The alkali-soluble resin of the present invention may have the above-mentioned epoxy group-containing structure, carboxyl group-containing structure, and polymerizable unsaturated bond-containing structure at the end of the main chain structure of the resin (polymer) structure or on a side chain, but preferably on a side chain. When these structures are on a side chain, the main chain structure of the polymer is not particularly limited, but the alkali-soluble resin of the present invention is preferably obtained by modifying an epoxy resin. Therefore, the alkali-soluble resin of the present invention preferably has a structure in which the above-mentioned epoxy group-containing structure, carboxyl group-containing structure, and polymerizable unsaturated bond-containing structure are bonded as side chains to a main chain structure derived from an epoxy resin. The epoxy resin that forms the main chain will be described later.

[0035] The alkali-soluble resin of the present invention has an epoxy equivalent of 50,000 g / equivalent or less. By having epoxy groups in a proportion such that the epoxy equivalent is 50,000 g / equivalent or less, good curability can be exhibited during post-curing, and the resulting cured product also has excellent solvent resistance. The epoxy equivalent of the alkali-soluble resin is preferably 30,000 g / equivalent or less. More preferably, it is 10,000 g / equivalent or less, and even more preferably, it is 5,000 g / equivalent or less. Of these, it is even more preferably 3,000 g / equivalent or less, particularly preferably 2,000 g / equivalent or less, and most preferably, it is 1,500 g / equivalent or less. Furthermore, from the viewpoint of storage stability, the epoxy equivalent of the alkali-soluble resin is preferably 400 g / equivalent or more, more preferably 550 g / equivalent or more, and even more preferably, it is 700 g / equivalent or more. That is, the epoxy equivalent of the alkali-soluble resin is preferably 400 to 50,000 g / equivalent, more preferably 550 to 30,000 g / equivalent, even more preferably 700 to 10,000 g / equivalent, even more preferably 700 to 5,000 g / equivalent, even more preferably 700 to 3,000 g / equivalent, particularly preferably 700 to 2,000 g / equivalent, and most preferably 700 to 1,500 g / equivalent. The epoxy equivalent of the alkali-soluble resin can be determined by dividing the resin solids content by the number of moles of epoxy groups contained in the resin. The epoxy equivalent can also be determined by a method in accordance with JIS K7236:2001.

[0036] The alkali-soluble resin of the present invention preferably has an acid value of 30 to 200 mgKOH / g. An acid value of 30 mgKOH / g or more results in the alkali-soluble resin having excellent curability during post-curing and excellent alkali resistance and solvent resistance of the cured product. Considering the need for a polymerizable unsaturated bond-containing structure so that the exposed portion becomes insoluble in the developer during the exposure and development process, the acid value is preferably 200 mgKOH / g or less. The acid value of the alkali-soluble resin is more preferably 35 to 160 mgKOH / g, and even more preferably 40 to 140 mgKOH / g. The acid value of the alkali-soluble resin can be measured by the method described in the Examples below.

[0037] The alkali-soluble resin of the present invention preferably has a double bond equivalent (weight per chemical equivalent of radically polymerizable double bonds) of 100 to 3,000 g / equivalent. A double bond equivalent of 3,000 g / equivalent or less results in the alkali-soluble resin having superior developability upon exposure. Furthermore, considering the need for an epoxy group-containing structure or a carboxyl group-containing structure for curability upon post-curing, the double bond equivalent is preferably 100 g / equivalent or more. The alkali-soluble resin preferably has a double bond equivalent of 250 to 2,000 g / equivalent, and even more preferably 400 to 1,000 g / equivalent. The double bond equivalent of the alkali-soluble resin can be measured by the method described in the Examples below. Alternatively, the iodine value may be calculated by measuring the number of ethylenic double bonds contained per gram of the alkali-soluble resin in accordance with the iodine value test method described in JIS K 0070:1992.

[0038] The alkali-soluble resin of the present invention may have structures other than those represented by the above formulas (1) to (5') in the side chains of the polymer, but the proportion of the other structures is preferably 60 mol % or less, more preferably 40 mol % or less, relative to the total number of moles of the structures represented by the above formulas (1) to (5') (100 mol %).

[0039] The alkali-soluble resin of the present invention has a carboxyl group, an epoxy group, and a radically polymerizable double bond, and is capable of undergoing crosslinking and polymerization reactions involving these groups, and therefore can be used alone as an alkali-soluble photosensitive resin, and is particularly suitable for use as a negative alkali-soluble photosensitive resin.

[0040] 2. Method for Producing Alkali-Soluble Resin In the present invention, the method for producing the alkali-soluble resin is not particularly limited as long as it produces an alkali-soluble resin having the above-mentioned structure, but a method of producing the alkali-soluble resin by modifying an epoxy resin is preferred. In this case, a method including a first step of reacting an epoxy resin (a) having two or more epoxy groups per molecule with a monobasic acid (b) having a hydroxyl group and an unsaturated monocarboxylic acid (c), and a second step of further reacting the reaction product obtained in the first step with a polybasic acid anhydride (d) is preferably used. The alkali-soluble resin of the present invention can be produced by adjusting the amounts of the monobasic acid (b) having a hydroxyl group and the unsaturated monocarboxylic acid (c) used so that the epoxy equivalent of the resulting resin is 50,000 g / equivalent or less. In this case, it is preferred to use a monobasic acid (b) having a primary alcoholic hydroxyl group as the monobasic acid (b) having a hydroxyl group. By using the monobasic acid (b) having a primary alcoholic hydroxyl group, the resulting reaction product has a primary alcohol that is more reactive with polybasic acid anhydrides than the secondary alcoholic hydroxyl group typically produced in the reaction of an epoxy group with a carboxylic acid, which allows the subsequent reaction with the polybasic acid anhydride to proceed smoothly, and the acid group can be introduced at a distance from the main chain, making it possible to provide the resulting alkali-soluble resin with superior alkali solubility and curability. The present invention also provides a method for producing such an alkali-soluble resin, i.e., a method for producing an alkali-soluble resin, which comprises a first step of reacting an epoxy resin (a) having two or more epoxy groups in one molecule with a monobasic acid (b) having a primary alcoholic hydroxyl group and an unsaturated monocarboxylic acid (c), and a second step of further reacting the reaction product obtained in the first step with a polybasic acid anhydride (d), wherein the amounts of the monobasic acid (b) having a primary alcoholic hydroxyl group and the unsaturated monocarboxylic acid (c) used in the first step are adjusted so that the epoxy equivalent of the resulting alkali-soluble resin is 50,000 g / equivalent or less.

[0041] In the method for producing an alkali-soluble resin of the present invention, the starting material epoxy resin (a) having two or more epoxy groups in one molecule is not particularly limited, and any known epoxy resin having two or more epoxy groups in one molecule can be used, including bisphenol-type epoxy resins; biphenyl-type epoxy resins; alicyclic epoxy resins; polyfunctional glycidylamine resins such as tetraglycidylaminodiphenylmethane; polyfunctional glycidyl ether resins such as tetraphenylglycidyl ether ethane; phenol novolac-type epoxy resins and cresol novolac-type epoxy resins. Examples of such epoxy resins include: reaction products of epichlorohydrin with polyphenol compounds obtained by the condensation reaction of phenolic compounds such as phenol, o-cresol, m-cresol, and naphthol with aromatic aldehydes having a phenolic hydroxyl group; reaction products of epichlorohydrin with polyphenol compounds obtained by the addition reaction of phenolic compounds with diolefin compounds such as divinylbenzene and dicyclopentadiene; products obtained by epoxidizing ring-opening polymerization products of 4-vinylcyclohexene-1-oxide with peracid; and epoxy resins having heterocycles such as triglycidyl isocyanurate. Furthermore, chain-extended products obtained by reacting two or more molecules of these epoxy resins with a chain extender such as a polybasic acid, a polyphenol compound, a polyfunctional amino compound, or a polyvalent thiol can also be used. Alternatively, the epoxy resin may be a homopolymer or copolymer of a monomer having an epoxy group, such as glycidyl (meth)acrylate or 3,4-epoxycyclohexylmethyl (meth)acrylate. Among these, it is preferable to use a novolac-type epoxy resin as a raw material in order to increase the number of ethylenically unsaturated bonds (polymerizable unsaturated double bonds) present in one molecule of the alkali-soluble resin (A) and improve photocurability.

[0042] The starting epoxy resin (a) having two or more epoxy groups per molecule preferably has an epoxy equivalent of 500 g / equivalent or less, more preferably 400 g / equivalent or less, and even more preferably 300 g / equivalent or less, in order to provide an alkali-soluble resin with excellent developability and low-temperature curing properties.

[0043] The monobasic acid (b) having a hydroxyl group is not particularly limited as long as it has a hydroxyl group and an acid group, but preferably has 2 to 12 carbon atoms, more preferably has 3 to 10 carbon atoms, and even more preferably has 4 to 8 carbon atoms.

[0044] Examples of the acid group of the hydroxyl group-containing monobasic acid (b) include a carboxyl group, a phenolic hydroxyl group, a phosphate group, and a sulfonic acid group, with a carboxyl group or a phenolic hydroxyl group being preferred, and a carboxyl group being more preferred.

[0045] Among the monobasic acids (b) having a hydroxyl group, those having a carboxyl group include monocarboxylic acids having a hydroxyl group such as glycolic acid, hydroacrylic acid, glyceric acid, dimethylolpropionic acid, dimethylolbutanoic acid, lactic acid, and tartaric acid.

[0046] Among these, those having a primary alcoholic hydroxyl group include monocarboxylic acids having one or more primary alcoholic hydroxyl groups, such as glycolic acid, hydroacrylic acid, glyceric acid, dimethylolpropionic acid, and dimethylolbutanoic acid, among which glycolic acid, dimethylolbutanoic acid, and dimethylolpropionic acid are preferred. These may be used alone or in combination of two or more.

[0047] The unsaturated monocarboxylic acid (c) is not particularly limited as long as it has an unsaturated bond and a carboxyl group, but preferably has 3 to 20 carbon atoms, more preferably has 3 to 10 carbon atoms, and even more preferably has 3 to 4 carbon atoms.

[0048] Examples of the unsaturated monocarboxylic acid (c) include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, β-acryloxypropionic acid, a reaction product of a hydroxyalkyl (meth)acrylate having one hydroxyl group and one (meth)acryloyl group with a dibasic acid anhydride, and a reaction product of a polyfunctional (meth)acrylate having one hydroxyl group and two or more (meth)acryloyl groups with a dibasic acid anhydride. Among these, those having a (meth)acryloyl group, such as acrylic acid and methacrylic acid, are preferred. Methacrylic acid is particularly preferred because it allows the resulting alkali-soluble resin to give a cured product with particularly excellent solvent resistance. These may be used alone or in combination.

[0049] In the method for producing an alkali-soluble resin of the present invention, in the first step of reacting an epoxy resin (a) having two or more epoxy groups in one molecule with a monobasic acid (b) having a hydroxyl group and an unsaturated monocarboxylic acid (c), the epoxy resin (a) may be reacted with the unsaturated monocarboxylic acid (c) and then with the monobasic acid (b) having a hydroxyl group, or the unsaturated monocarboxylic acid (c) and the monobasic acid (b) having a hydroxyl group may be reacted with the epoxy resin (a) all at once, or the epoxy resin (a) may be reacted with the monobasic acid (b) having a hydroxyl group and then with the unsaturated monocarboxylic acid (c).

[0050] In the first step, the total amount of the hydroxyl-containing monobasic acid (b) and the unsaturated monocarboxylic acid (c) used is preferably 0.2 to 0.79 moles per chemical equivalent (molar equivalent) of epoxy groups in the epoxy resin. By using them in such a ratio, the curability and cured product properties of the final alkali-soluble resin obtained tend to be good. The amount is preferably 0.3 to 0.76 moles, more preferably 0.4 to 0.73 moles.

[0051] The amount of the monobasic acid (b) having a hydroxyl group used is preferably 0.01 to 0.5 moles, where the total amount of the monobasic acid (b) having a hydroxyl group and the unsaturated monocarboxylic acid (c) is 1 mole. By using the monobasic acid (b) having a hydroxyl group in such a ratio, the effect of using the monobasic acid (b) having a hydroxyl group can be more fully exhibited, while the amount of polymerizable unsaturated double bonds introduced can be sufficiently ensured, and the finally obtained alkali-soluble resin can have better curability and cured product physical properties.

[0052] In the first step of the method for producing an alkali-soluble resin of the present invention, the reaction of the epoxy resin (a) with the monobasic acid (b) having a hydroxyl group and the unsaturated monocarboxylic acid (c) may be carried out in either order or simultaneously, as described above. These reactions can be carried out in the presence or absence of a diluent such as a polymerizable compound or solvent, as described below, in the presence of a polymerization inhibitor such as hydroquinone or oxygen, and a reaction catalyst such as a tertiary amine, a tertiary phosphine such as trimethylphosphine, tributylphosphine, or triphenylphosphine, lithium chloride, a quaternary ammonium salt, or a quaternary phosphonium salt, typically at 80 to 130°C. From the viewpoints of reaction efficiency, stability during the reaction, and storage stability of the alkali-soluble resin, tertiary phosphines are preferred, with triphenylphosphine being particularly preferred.

[0053] The amount of the reaction catalyst is not particularly limited, but is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.2 to 2 parts by mass, per 100 parts by mass of the epoxy resin (a) having two or more epoxy groups per molecule.

[0054] Furthermore, in the first step, a polymerization inhibitor may be used. The polymerization inhibitor is not particularly limited, and known ones can be used, for example, benzoquinone, hydroquinones (e.g., hydroquinone, hydroquinone monomethyl ether, p-tert-butylhydroquinone, p-benzoquinone, etc.), phenols (e.g., 2,6-di-t-butyl-4-methylphenol, 6-t-butyl-2,4-dimethylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol)), catechols (e.g., p-tert-butylcatechol, etc.), amines (e.g., N,N-diethylhydroxylamine, etc.), 1,1-diphenyl-2-picrylhydrazyl, tri-p-nitrophenylmethyl, phenothiazine, piperidine 1-oxyls (e.g., 2,2,6,6-tetramethylpiperidine 1-oxyl, etc.), oxygen, etc. can be used.

[0055] When the polymerization inhibitor is used in the first step, the amount of the polymerization inhibitor used is preferably 0.001 to 1 mass %, more preferably 0.01 to 0.5 mass %, based on 100 mass % of the epoxy resin (a) having two or more epoxy groups per molecule.

[0056] The reaction temperature in the first step is not particularly limited as long as the reaction proceeds, but is preferably 80 to 140°C. By performing the reaction at such a temperature, the reaction can proceed efficiently. The reaction temperature is more preferably 85 to 135°C, and even more preferably 90 to 130°C.

[0057] Hereinafter, the reaction product obtained in the first step may be referred to as a "modified epoxy resin intermediate." In the second step of the above-mentioned method for producing an alkali-soluble resin, the modified epoxy resin intermediate is reacted with a polybasic acid anhydride (d), whereby the polybasic acid anhydride (d) reacts with the hydroxyl groups present in the modified epoxy resin intermediate to obtain the alkali-soluble resin of the present invention having carboxyl groups introduced therein. The resulting alkali-soluble resin can be developed in an alkali, and therefore can be used as an alkali-developable curable resin for image formation, etc.

[0058] When a monobasic acid (b) having a primary alcoholic hydroxyl group is used as the monobasic acid (b) having a hydroxyl group in the first step, the modified epoxy resin intermediate contains primary hydroxyl groups derived from the monobasic acid (b) having a primary alcoholic hydroxyl group and hydroxyl groups generated by ring-opening of the epoxy group as a result of the reaction of the monobasic acid (b) having a primary alcoholic hydroxyl group with the epoxy group in the epoxy resin and the unsaturated monocarboxylic acid (c). In this case, the polybasic acid anhydride (d) can react with either hydroxyl group in the second step. However, when a monobasic acid (b) having a primary alcoholic hydroxyl group is used as the monobasic acid (b) having a hydroxyl group, the primary hydroxyl group derived from the monobasic acid (b) having a primary alcoholic hydroxyl group is less sterically hindered than the hydroxyl group generated by ring-opening of the epoxy group in the second step, and therefore it is believed that the polybasic acid anhydride (d) preferentially reacts with the primary hydroxyl group derived from the monobasic acid (b) having a primary alcoholic hydroxyl group. In the above formulas (3) and (3′), the terminal —R １ -O-R ２ is a structure represented by the above formula (9), or in formulas (4) and (4'), R ４ An example of a structure obtained by such a reaction is one in which the subsequent terminal structure is represented by the above formula (12). In this case, in the resulting alkali-soluble resin, the remaining epoxy group or the double bond moiety introduced by the reaction with the unsaturated monocarboxylic acid (c) and the carboxyl group introduced by the reaction with the polybasic acid anhydride (d) are sufficiently separated, making it easier for the functions of each functional group to be effectively exerted, and therefore the alkali-soluble resin has better curability and alkali developability.

[0059] The polybasic acid anhydride (d) is not particularly limited, but preferably has 3 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, and even more preferably 4 to 10 carbon atoms.

[0060] Examples of the polybasic acid anhydride (d) include dibasic acid anhydrides such as phthalic anhydride, succinic anhydride, octenyl succinic anhydride, pentadodecenyl succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, and trimellitic acid; and aliphatic or aromatic tetrabasic acid dianhydrides such as biphenyltetracarboxylic dianhydride, diphenylethertetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. These polybasic acid anhydrides can be used alone or in combination. Among these, it is preferable to use dibasic acid anhydrides. Furthermore, from the viewpoint of providing a cured product of the resulting alkali-soluble resin with particularly excellent solvent resistance, polybasic acid anhydrides, such as phthalic anhydride, which give an alkali-soluble resin having a cyclic structure in its structure, are particularly preferred.

[0061] In the second step, the polybasic acid anhydride (d) is preferably reacted in a ratio of 0.1 mol to 1.1 mol per chemical equivalent of hydroxyl groups in the modified epoxy resin intermediate obtained by the reaction in the first step. By reacting the polybasic acid anhydride (d) in this manner, the addition reaction of the polybasic acid anhydride (d) can be carried out efficiently, and carboxyl groups can be suitably introduced into the resulting alkali-soluble resin.

[0062] The temperature for the reaction of the modified epoxy resin intermediate with the polybasic acid anhydride (d) in the second step is not particularly limited as long as the reaction proceeds, but is preferably 45 to 75°C. By carrying out the reaction at such a temperature, the reaction can proceed efficiently while suppressing the formation of high molecular weight products and gelation due to the reaction between the epoxy groups and the introduced carboxyl groups. The reaction temperature is more preferably 50 to 70°C, and even more preferably 55 to 65°C.

[0063] The reaction of the modified epoxy resin intermediate with the polybasic acid anhydride (d) in the second step is preferably carried out in the presence or absence of a diluent such as a polymerizable compound or solvent described below, and in the presence of a polymerization inhibitor such as hydroquinone or oxygen. If necessary, the reaction catalyst used in obtaining the modified epoxy resin intermediate may be added, and a tertiary phosphine is also preferred, with triphenylphosphine being particularly preferred. The reaction of the modified epoxy resin intermediate with the polybasic acid anhydride (d) is conveniently carried out by adding the polybasic acid anhydride (d) to the reaction solution following the reaction to produce the modified epoxy resin intermediate.

[0064] A tertiary amine may be added to the reaction of the modified epoxy resin intermediate with the polybasic acid anhydride (d) in the second step. By adding a tertiary amine, the reaction efficiency is improved and the second step can be completed in a shorter time. As the tertiary amine, one or more of trimethylamine, triethylamine, tributylamine, tripropylamine, trihexylamine, etc. can be used.

[0065] When a tertiary amine is used in the second step, the amount of the tertiary amine used is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.15 to 1 part by mass, per 100 parts by mass of the epoxy resin (a) having two or more epoxy groups per molecule.

[0066] The method for producing the alkali-soluble resin may include other steps as long as it includes the first and second steps. Examples of such other steps include a step of linking molecules.

[0067] 3. Photosensitive Resin Composition As described above, the alkali-soluble resin of the present invention can be used alone as a resist material, but by forming a resin composition containing at least an alkali-soluble resin, a polymerizable compound, and a photopolymerization initiator, a coating film having a crosslinked structure can be obtained through a thermal or photoreaction. Such a photosensitive resin composition containing at least the alkali-soluble resin of the present invention, a polymerizable compound, and a photopolymerization initiator also constitutes one aspect of the present invention. In this specification, the alkali-soluble resin of the present invention is also referred to as alkali-soluble resin (A) in the photosensitive resin composition.

[0068] In the photosensitive resin composition of the present invention, the content of the alkali-soluble resin (A) is not particularly limited and may be appropriately set depending on the application, the blending of other components, etc. For example, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of the total solids content of the photosensitive resin composition. It is also preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less. That is, the content of the alkali-soluble resin (A) is preferably 5 to 80% by mass, more preferably 10 to 75% by mass, and even more preferably 15 to 70% by mass, relative to 100% by mass of the total solids content of the photosensitive resin composition. In this specification, the term "total solids content" refers to the total amount of components that form the cured product, i.e., the total amount of components (solids and non-volatiles) excluding solvents and the like that volatilize during the formation of the cured product. Specifically, it means the total solid mass of the alkali-soluble resin, the polymerizable compound, the photopolymerization initiator, and, if other components that form a cured product (for example, a colorant, a dispersant, etc.) are included, the total solid mass of these components.

[0069] [Polymerizable Compound] The polymerizable compound contained in the photosensitive resin composition of the present invention 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 monofunctional compounds having one polymerizable unsaturated group per molecule and polyfunctional compounds having two or more polymerizable unsaturated groups per molecule. Examples of the monofunctional compound include N-substituted maleimide monomers; (meth)acrylic acid esters; (meth)acrylamides; unsaturated monocarboxylic acids; unsaturated polycarboxylic acids; unsaturated monocarboxylic acids in which the unsaturated group and the carboxyl group are chain-extended; unsaturated acid anhydrides; aromatic vinyls; conjugated dienes; vinyl esters; vinyl ethers; N-vinyl compounds; unsaturated isocyanates; and the like. Monomers having an active methylene group or an active methine group can also be used.

[0070] Examples of the polyfunctional compound include the following compounds: bifunctional (meth)acrylate compounds such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, bisphenol A alkylene oxide di(meth)acrylate, and bisphenol F alkylene oxide di(meth)acrylate;Trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, ethylene oxide-added ditrimethylolpropane tetra(meth)acrylate, ethylene oxide-added pentaerythritol tetra(meth)acrylate, ethylene oxide-added dipentaerythritol hexa(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate tri- or higher functional (meth)acrylate compounds such as propylene oxide-added ditrimethylolpropane tetra(meth)acrylate, propylene oxide-added pentaerythritol tetra(meth)acrylate, propylene oxide-added dipentaerythritol hexa(meth)acrylate, ε-caprolactone-added trimethylolpropane tri(meth)acrylate, ε-caprolactone-added ditrimethylolpropane tetra(meth)acrylate, ε-caprolactone-added pentaerythritol tetra(meth)acrylate, ε-caprolactone-added dipentaerythritol hexa(meth)acrylate, dipentaerythritol pentaacrylate succinic acid-modified product, pentaerythritol triacrylate succinic acid-modified product, dipentaerythritol pentaacrylate phthalic acid-modified product, and pentaerythritol triacrylate phthalic acid-modified product;

[0071] polyfunctional vinyl ethers such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, and ethylene oxide-added dipentaerythritol hexavinyl ether; vinyl ether group-containing (meth)acrylic acid esters such as 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, and 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate;

[0072] polyfunctional allyl ethers such as ethylene glycol diallyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, propylene glycol diallyl ether, butylene glycol diallyl ether, hexanediol diallyl ether, bisphenol A alkylene oxide diallyl ether, bisphenol F alkylene oxide diallyl ether, trimethylolpropane triallyl ether, ditrimethylolpropane tetraallyl ether, glycerin triallyl ether, pentaerythritol tetraallyl ether, dipentaerythritol pentaallyl ether, dipentaerythritol hexaallyl ether, ethylene oxide-added trimethylolpropane triallyl ether, ethylene oxide-added ditrimethylolpropane tetraallyl ether, ethylene oxide-added pentaerythritol tetraallyl ether, and ethylene oxide-added dipentaerythritol hexaallyl ether; Allyl group-containing (meth)acrylic acid esters such as allyl (meth)acrylate; polyfunctional (meth)acryloyl group-containing isocyanurates such as tri(acryloyloxyethyl)isocyanurate, tri(methacryloyloxyethyl)isocyanurate, alkylene oxide-added tri(acryloyloxyethyl)isocyanurate, and alkylene oxide-added tri(methacryloyloxyethyl)isocyanurate; polyfunctional allyl group-containing isocyanurates such as triallyl isocyanurate; polyfunctional urethane (meth)acrylates obtained by reacting polyfunctional isocyanates such as tolylene diisocyanate, isophorone diisocyanate, and xylylene diisocyanate with hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; polyfunctional aromatic vinyls such as divinylbenzene; etc. These polymerizable compounds may be used alone or in combination of two or more.

[0073] Among the above-mentioned compounds, polyfunctional polymerizable compounds are preferred as the polymerizable compound contained in the photosensitive resin composition of the present invention, from the viewpoint of further enhancing the curability of the photosensitive resin composition. The number of functional groups (number of functional groups) of the polyfunctional polymerizable compound is preferably 3 or more, more preferably 4 or more. The number of functional groups is preferably 10 or less, more preferably 8 or less. From the viewpoints of reactivity, economy, availability, etc., preferred examples of polyfunctional polymerizable compounds include compounds having a (meth)acryloyl group, such as polyfunctional (meth)acrylate compounds, polyfunctional urethane (meth)acrylate compounds, and (meth)acryloyl group-containing isocyanurate compounds, and more preferred examples include polyfunctional (meth)acrylate compounds. By including a compound having a (meth)acryloyl group, the photosensitive resin composition has superior photosensitivity and curability, and a cured product with even higher hardness and transparency can be obtained. It is even more preferred to use a polyfunctional (meth)acrylate compound having three or more functional groups as the polyfunctional polymerizable compound.

[0074] The polymerizable compound includes those with various structures, and its molecular weight is not particularly limited. However, from the viewpoint of handling, the polymerizable compound contained in the photosensitive resin composition of the present invention preferably has a molecular weight of, for example, 2000 or less.

[0075] On the other hand, a polymer having a vinyl ether group in the side chain improves the curability of the resin composition but may reduce storage stability. Therefore, in terms of storage stability, it is preferable that the photosensitive resin composition does not contain a polymer having a vinyl ether group in the side chain as a polymerizable compound.

[0076] In the photosensitive resin composition of the present invention, the content of the polymerizable compound is not particularly limited and may be appropriately set as long as it is within a range in which the effects of the present invention are exhibited. However, in order to allow the photosensitive resin composition to have an appropriate viscosity, the content is preferably 5 to 60 mass %, and more preferably 10 to 50 mass %, relative to 100 mass % of the total solid content of the photosensitive resin composition.

[0077] [Photopolymerization initiator] The photopolymerization initiator contained in the photosensitive resin composition of the present invention is preferably a radically polymerizable photopolymerization initiator that generates polymerization initiating radicals upon irradiation with active energy rays such as electromagnetic waves or electron beams. Specific examples of the photopolymerization initiator 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-one ("IRGACURE369", manufactured by BASF), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one ("IRGACURE379", manufactured by BASF); 2,2-dimethoxy-1,2-diphenylethan-1-one ("IRGACURE651", manufactured by BASF), and phenylglyoxylic acid methyl ester ("DAROCURE benzyl ketal compounds such as 1-hydroxy-cyclohexyl-phenyl-ketone ("IRGACURE184", manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propan-1-one ("DAROCUR1173", manufactured by BASF), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one ("IRGACURE2959", manufactured by BASF), 2-hydroxy -1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one ("IRGACURE 127", manufactured by BASF Corporation), [1-hydroxy-cyclohexyl-phenyl-ketone + benzophenone] ("IRGACURE 500", manufactured by BASF Corporation), and other hydroketone compounds; as well as other alkylphenone compounds exemplified in paragraphs

[0084] to

[0086] of JP-A No. 2013-227485;1,2-Octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime) ("OXE01", manufactured by BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) ("OXE02", manufactured by BASF), 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone ("OXE03", manufactured by BASF), 1-[9-ethyl Examples of the photopolymerization initiator include oxime ester compounds such as [-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime) ("OXE04", manufactured by BASF); benzophenone compounds; benzoin compounds; thioxanthone compounds; halomethylated triazine compounds; halomethylated oxadiazole compounds; biimidazole compounds; titanocene compounds; benzoic acid ester compounds; acridine compounds; and phosphine oxide compounds. Among these, aminoketone compounds and oxime ester compounds are preferred. One or more of the above photopolymerization initiators can be used.

[0078] The content of the photopolymerization initiator is not particularly limited as long as it is within a range in which the effects of the present invention are exhibited, and may be set as appropriate. For example, the content is preferably 0.3 to 20 mass%, more preferably 0.5 to 10 mass%, and even more preferably 1 to 8 mass%, relative to 100 mass% of the total solid content of the photosensitive resin composition of the present invention.

[0079] The photosensitive resin composition of the present invention (also simply referred to as a resin composition) contains at least a specific alkali-soluble resin having an epoxy group-containing structure, a carboxyl group-containing structure, and a polymerizable unsaturated bond-containing structure and having an epoxy equivalent of 50,000 g / equivalent or less, a polymerizable compound, and a photopolymerization initiator, and may further contain one or more other components as necessary, and one or more of each component can be used. The other components will be described below.

[0080] [Photoacid Generator] The photosensitive resin composition of the present invention preferably further contains a photoacid generator. By further containing a photoacid generator, the curability of the photosensitive resin composition can be further improved. The photoacid generator is a compound that generates an acid when exposed to active energy rays such as radiation, and examples of the photoacid generator include strong acids such as toluenesulfonic acid or boron tetrafluoride; onium salts such as sulfonium salts, ammonium salts, phosphonium salts, iodonium salts, and selenium salts; iron-arene complexes; silanol-metal chelate complexes; sulfonic acid derivatives such as disulfones, disulfonyldiazomethanes, disulfonylmethanes, sulfonylbenzoylmethanes, imidosulfonates, and benzoin sulfonates; and organic halogen compounds.

[0081] The content of the photoacid generator is preferably 0.3 to 20% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 8% by mass, relative to 100% by mass of the total solid content of the photosensitive resin composition.

[0082] [Solvent] The photosensitive resin composition of the present invention preferably contains a solvent. By containing a solvent, it becomes possible to form a film by coating the photosensitive resin composition on a substrate. The solvent is not particularly limited, and examples thereof include hydrocarbons such as toluene and xylene; cellosolves such as cellosolve and butyl cellosolve; carbitols such as carbitol and butyl carbitol; esters such as cellosolve acetate, carbitol acetate, (di)propylene glycol monomethyl ether acetate, (di)methyl glutarate, (di)methyl succinate, and (di)methyl adipate; ketones such as methyl isobutyl ketone and methyl ethyl ketone; and ethers such as (di)ethylene glycol dimethyl ether.

[0083] The content of the solvent is not particularly limited and is preferably set appropriately depending on the form of use of the photosensitive resin composition (e.g., coating, etc.). For example, the content of the solvent is preferably set so that the total solid content (solid content concentration) in 100% by mass of the photosensitive resin composition is 1 to 90% by mass. The total solid content in 100% by mass of the photosensitive resin composition is more preferably 5 to 70% by mass, and particularly preferably 10 to 50% by mass.

[0084] If necessary, the photosensitive resin composition of the present invention may further contain known additives such as phosphoric acid derivatives, colorants, photoacid generators, photobase generators, polyfunctional thiol compounds, dispersants, fillers such as talc, clay, barium sulfate, and silica, antifoaming agents, coupling agents, leveling agents, sensitizers, mold release agents, lubricants, plasticizers, antioxidants, ultraviolet absorbers, flame retardants, polymerization inhibitors, and thickeners. Furthermore, various reinforcing fibers can be used as reinforcing fibers to produce fiber-reinforced composite materials.

[0085] The content of the known additives in the photosensitive resin composition of the present invention is preferably 70% by mass or less, based on 100% by mass of the photosensitive resin composition. It is more preferably 60% by mass or less, and even more preferably 50% by mass or less. The lower limit can be set depending on the application, but is 0% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1% by mass or more. That is, the content of the additives is preferably 0 to 70% by mass, more preferably 0.1 to 60% by mass, and even more preferably 1 to 50% by mass, based on 100% by mass of the photosensitive resin composition.

[0086] 4. Method for Preparing Photosensitive Resin Composition The method for preparing the photosensitive resin composition of the present invention is not particularly limited, and any known method may be used. For example, a method of mixing and dispersing the above-mentioned components using various mixers or dispersers may be used. The method for preparing the photosensitive resin composition of the present invention may also include other steps in addition to the step of mixing and dispersing the components. For example, when the photosensitive resin composition contains a colorant, a dispersing treatment step for the colorant may be used.

[0087] 5. Cured Product The alkali-soluble resin, alkali-soluble resin solution, or photosensitive resin composition of the present invention can provide a cured product that has excellent solvent resistance even when cured at low temperatures. Such a cured product of the alkali-soluble resin or photosensitive resin composition of the present invention also constitutes the present invention.

[0088] When the cured product is a cured film, its film thickness is preferably 0.1 μm or more. A film thickness of 0.1 μm or more can exhibit even better solvent resistance. The film thickness is more preferably 0.5 μm or more, and even more preferably 1 μm or more. The upper limit of the film thickness is not particularly limited and may be set appropriately depending on the purpose and use of the cured film, but is preferably, for example, 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. That is, the film thickness is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 1 to 10 μm. The film thickness of the cured film can be measured using a commercially available film thickness measuring device.

[0089] The method for obtaining the cured product is not particularly limited, and any known method may be used. For example, the above-mentioned alkali-soluble resin (solution) or photosensitive resin composition may be applied to a substrate or molded, and then cured by drying, heating, or irradiating with energy rays such as ultraviolet rays, or a combination of these, to obtain a cured product. Among these, a preferred method for producing a cured product includes a step of applying the photosensitive resin composition to a substrate to form a coating film, a step of irradiating the formed coating film with light, and a step of heating the irradiated coating film at 160°C or less. Examples of the substrate include those similar to the substrate of the color filter described below.

[0090] The method for applying the photosensitive resin composition to a substrate to form a coating film is not particularly limited, and can be any known method such as spin coating, slit coating, roll coating, or cast coating. In the above production method, it is preferable to apply the photosensitive resin composition to the substrate, and then dry the applied product to form a coating film. The drying can be performed by any known method, and specifically, can be performed by the same method as the drying method described in the "Arrangement Step" in [Color Filter Manufacturing Method] below.

[0091] The method for irradiating the formed coating film with light is not particularly limited and can be performed by a known method, specifically, the same method as the method described in the "light irradiation step" of [Color filter manufacturing method] described below. When irradiating the coating film with light, light irradiation may be performed through a photomask. As the photomask, a mask having a light-shielding portion formed according to the desired pattern may be used. When light irradiation is performed through a photomask, it is preferable to perform a development step thereafter. By performing the development step, the desired pattern can be formed in the coating film. The development method is not particularly limited and can be performed by a known method, specifically, the same method as the method described in the "development step" of [Color filter manufacturing method] described below.

[0092] The above-mentioned production method also includes a step of heating the light-irradiated coating film at 160°C or less. Because the above-mentioned production method uses the photosensitive resin composition described above, the heating step (post-curing step) after light irradiation can be performed under relatively low-temperature conditions of 160°C or less. The heating temperature is preferably 155°C or less, and more preferably 150°C or less. The lower limit of the heating temperature is preferably 70°C or more, and more preferably 90°C or more, in terms of maintaining curability. That is, the heating temperature is preferably 70 to 160°C, more preferably 90 to 155°C, and even more preferably 90 to 150°C. The heating method other than the temperature is not particularly limited and can be performed by any known method, for example, the same method as the method described in the "heating step" section of [Color filter production method] below.

[0093] 6. Applications The alkali-soluble resin and photosensitive resin composition of the present invention have excellent alkali developability. Furthermore, even under low-temperature curing conditions of 160°C or less, for example, around 90°C, the curing reaction proceeds sufficiently, yielding a cured product with excellent solvent resistance. Therefore, they are suitable for applications requiring sufficient curing under low-temperature conditions or applications requiring solvent resistance. Specifically, the alkali-soluble resin and photosensitive resin composition of the present invention are suitable for applications including color filters, black matrices, photospacers, black column spacers, inks, printing plates, printed wiring boards, semiconductor elements, photoresists, insulating films, films, organic protective films, and other components of various optical components and electrical and electronic devices, such as those used in liquid crystal, organic electroluminescent (EL), quantum dot, and micro-LED liquid crystal displays, solid-state imaging devices, and touch panel displays. In particular, they are preferably used in color filter applications. The photosensitive resin composition of the present invention is suitable for use as an optical material, and also as a negative-tone film.

[0094] [Color Filter] A color filter having a cured product of the above-mentioned photosensitive resin composition on a substrate is also one of the preferred applications of the alkali-soluble resin of the present invention and the photosensitive resin composition containing the same. In a color filter, the cured product formed from the photosensitive resin composition of the present invention is particularly suitable as a segment that requires coloring, such as a black matrix or each pixel of red, green, blue, yellow, etc., but is also suitable as a material for a segment that does not necessarily require coloring, such as a photospacer, a protective layer, or an alignment control rib.

[0095] 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., color filters for LCDs). 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 a transparent substrate. If necessary, the substrate may be subjected to corona discharge treatment, ozone treatment, chemical treatment with a silane coupling agent, or the like.

[0096] [Method for manufacturing a color filter] To obtain the color filter, for example, a method is preferably adopted that includes a step of disposing the above-mentioned 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 heating step) for each color pixel. The order in which the pixels of each color are formed is not particularly limited. Each step is described below.

[0097] (1) Disposing Step (Preferably Coating Step) The disposing step is preferably carried out by coating. Examples of methods for coating the photosensitive resin composition on a substrate include spin coating, slit coating, roll coating, and cast coating, and any of these methods can be preferably used. In the disposing step, it is also preferable to dry the coating film after coating the photosensitive resin composition on the substrate. The coating film can be dried using, for example, a hot plate, an IR oven, a convection oven, or the like. Drying conditions are appropriately selected depending on the boiling point of the solvent components contained, the type of curing component, the film thickness, the performance of the dryer, and the like, but it is usually preferable to carry out the drying at a temperature of 50 to 160°C for about 10 seconds to 60 minutes.

[0098] (2) Light Irradiation Step In the light irradiation step, examples of the light source for the active energy ray used include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, medium-pressure mercury lamps, low-pressure mercury lamps, carbon arcs, and fluorescent lamps, and laser light sources such as argon ion lasers, YAG lasers, excimer lasers, nitrogen lasers, helium-cadmium lasers, and semiconductor lasers. Examples of the exposure method include proximity methods, mirror projection methods, and stepper methods, with the proximity method being preferred. In the light irradiation step, depending on the application, the active energy ray may be irradiated through a predetermined mask pattern. In this case, the exposed area is cured, and the cured area becomes insoluble or poorly soluble in a developer.

[0099] (3) Development Step The development step is a step in which, after the above-described light irradiation step, development is performed using a developer to remove unexposed areas and form a pattern. This allows a patterned cured film to be obtained. The development process can usually be performed at a development temperature of 10 to 50°C by methods such as immersion development, spray development, brush development, and ultrasonic development. The developer used in the development step is not particularly limited as long as it dissolves the photosensitive resin composition, but typically an organic solvent or an alkaline aqueous solution is used, and a mixture of these may also be used. When an alkaline aqueous solution is used as the developer, it is preferable to wash with water after development. Examples of organic solvents and alkaline aqueous solutions include those similar to those described in JP 2015-157909 A.

[0100] (4) Heating Step The heating step is a step (also referred to as a "post-curing step") in which the exposed area (cured area) is further cured by baking after the above-mentioned development step. For example, a light source such as a high-pressure mercury lamp is used, and the cured area is further cured by baking at 0.5 to 5 J / cm. ２ and a step of post-heating at a temperature of, for example, 60 to 200° 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.

[0101] The heating step is generally carried out at a temperature of approximately 200 to 260°C. However, by using the photosensitive resin composition, sufficient curing can be achieved under relatively low temperatures of 200°C or less, preferably 160°C or less. Therefore, excellent solvent resistance can be obtained without impairing the properties retained by the substrate or the cured product. In the heating step, the heating temperature is preferably 160°C or less, more preferably 155°C or less, and even more preferably 150°C or less. Furthermore, the heating temperature is preferably 70°C or more, more preferably 90°C or more, and even more preferably 95°C or more. That is, the heating temperature is preferably 70 to 160°C, more preferably 90 to 155°C, and even more preferably 95 to 150°C. The heating time in the heating step is not particularly limited, but is preferably, for example, 5 to 60 minutes. Furthermore, the heating method is also not particularly limited, but can be performed using heating equipment such as a hot plate, convection oven, or high-frequency heater.

[0102] The thickness of the cured film obtained by the heating step (i.e., the cured coating film obtained by thermally curing the photosensitive resin composition) is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 1 to 10 μm.

[0103] [Display Device] The above-described color filter can be suitably used in a display device. That is, a cured product obtained by curing the alkali-soluble resin or photosensitive resin composition of the present invention can be suitably used as a display device member. A display device member containing a cured product obtained by curing the alkali-soluble resin or photosensitive resin composition of the present invention, and a display device containing the display device member, also constitute the present invention. The cured product (cured film) formed from the photosensitive resin composition is stable, has excellent adhesion and solvent resistance, and is highly hard, and also exhibits high smoothness and high transmittance, making it particularly suitable as a transparent member and also useful as a protective film or insulating film in various display devices.

[0104] Suitable examples of the display device include a liquid crystal display device, a solid-state imaging device, a touch panel display device, etc. When the cured product (cured film) is used as a member for a display device, the member may be a film-like single-layer or multi-layer member composed of the cured film, a member in which another layer is further combined with the single-layer or multi-layer member, or a member containing the cured film in its configuration.

[0105] The alkali-soluble resin and photosensitive resin composition of the present invention have excellent alkali developability and can provide a cured product having excellent solvent resistance even under low-temperature curing conditions. The alkali-soluble resin and photosensitive resin composition of the present invention can be suitably used in various applications such as electrical and electronic devices, including as various optical members and components used in liquid crystal, organic EL, quantum dot, and micro LED liquid crystal displays, solid-state imaging devices, and touch panel display devices.

[0106] The present invention will be described in further detail below with reference to examples. However, the following examples do not limit the present invention, and all modifications and variations within the spirit of the present invention are included within the technical scope of the present invention. The present invention will be specifically illustrated with 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 examples, various physical properties were evaluated as follows.

[0107] [Evaluation Method] (1) Acid Value 3 g of resin solution was precisely weighed out and dissolved in a mixed solvent of 90 g of acetone and 10 g of water. The solution was titrated using a 0.1 N KOH aqueous solution as the titrant. The titration was performed using an automatic titrator (product name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of solids (mg KOH / g) was determined from the acid value of the resin solution and the resin solids content. The solids content of the resin solution was determined as follows. Approximately 1 g of the resin solution was weighed into an aluminum cup, dissolved by adding approximately 3 g of acetone, and then allowed to dry naturally at room temperature. The resin solution was then dried under vacuum at 140°C for 1.5 hours using a vacuum dryer (manufactured by EYELA, product name: VOS-301SD), allowed to cool in a desiccator, and its mass was measured. The solids content (mass%) of the resin solution was calculated from the mass loss. (2) Epoxy Equivalent (g / eq) This was determined by dividing the mass (g) of the resin solid content by the number of moles (mol) of epoxy groups contained in the resin. (3) Double Bond Equivalent (g / eq) This was determined by dividing the mass (g) of the resin solid content by the number of double bonds (mol) of the resin. (4) Alkali Solubility Each alkali-soluble resin solution was used to prepare the formulations shown in Table 1, to obtain photosensitive resin compositions. Each was applied to a glass plate by spin coating, dried at 80°C for 30 minutes, cooled to room temperature, and immersed in a 1% by mass aqueous sodium carbonate solution at 30°C for 30 seconds, and the presence of a remaining coating film was visually evaluated according to the following criteria: ○: Good solubility (no coating film at all) ×: Poor solubility (coating film remains) (5) Photocurability The alkali solubility evaluation test plate obtained above was applied with 500 mJ / cm ２After being irradiated with light, the sample was immersed in a 1% by mass aqueous sodium carbonate solution at 30°C for 30 seconds and visually evaluated according to the following criteria: ○: Good curability (no peeling of coating film) ×: Poor curability (peeling of coating film) (6) Solvent Resistance After the above photocurability evaluation, the sample was heat treated (post-cured) at 90°C for 1 hour, immersed in N-methyl-2-pyrrolidone at room temperature for 30 seconds, rinsed with water, and visually evaluated according to the following criteria. ◎: Extremely good solvent resistance (no whitening observed on the coating film) ○: Good solvent resistance (very slight whitening observed on the coating film) △: Slightly poor solvent resistance (slight whitening observed on the coating film) ×: Poor solvent resistance (significant whitening observed on the coating film) (7) Storage stability Each alkali-soluble resin solution was dispensed in an 8 g aliquot into a 10 cc screw tube and left to stand in a thermostatic bath at 40°C. The screw tube was turned over every 24 hours and visually evaluated according to the following criteria: ◎: No gel formation was observed on the bottom after 1 month ○: No gel formation was observed on the bottom after 2 weeks △: Gel formation was observed on the bottom within 1 to 2 weeks ×: Gel formation was observed on the bottom within 1 week

[0108] Example 1 Synthesis of alkali-soluble resin solution A-1 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 118.8 parts of propylene glycol monomethyl ether acetate, 207.6 parts of cresol novolac epoxy resin YDCN-704A (manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent 207.6 g / equivalent), 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 (manufactured by Kawaguchi Chemical Industry Co., Ltd., 2,2'-methylenebis(4-methyl-6-t-butylphenol)) as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 20.1 parts of dimethylolpropionic acid and 40.4 parts of acrylic acid were added, and an addition reaction was carried out. One hour after the addition of acrylic acid, an additional 0.4 parts of triphenylphosphine was added, the temperature was raised to 120°C, and the reaction was continued for an additional 6 hours to complete the addition reaction of dimethylolpropionic acid and acrylic acid. Thereafter, 79.2 parts of propylene glycol monomethyl ether acetate was added and the mixture was cooled to room temperature. Then, 28.8 parts of succinic anhydride was added and the reaction was continued at 60°C for 9 hours. 247.4 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-1. The physical properties of the resulting alkali-soluble resin are shown in Table 1.

[0109] Example 2 Synthesis of alkali-soluble resin solution A-2 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 109.8 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.2 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 20.1 parts of dimethylolpropionic acid and 20.2 parts of acrylic acid were added and an addition reaction was carried out. One hour after the addition of acrylic acid, an additional 0.4 parts of triphenylphosphine was added, and the temperature was raised to 120 ° C. and the reaction was continued for another 5 hours, completing the dimethylolpropionic acid and acrylic acid addition reaction. Thereafter, 73.2 parts of propylene glycol monomethyl ether acetate was added and cooled to room temperature, after which 26.6 parts of succinic anhydride was added and the reaction was continued at 60°C for 8 hours, and 228.8 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-2. Various physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0110] Example 3 Synthesis of alkali-soluble resin solution A-3 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 123.6 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 26.8 parts of dimethylolpropionic acid and 38.7 parts of methacrylic acid were added and an addition reaction was carried out. An additional 0.4 parts of triphenylphosphine was added one hour after the addition of methacrylic acid, and the temperature was raised to 120 ° C. and the reaction was continued for another 6 hours, completing the dimethylolpropionic acid and methacrylic acid addition reaction. Thereafter, 82.4 parts of propylene glycol monomethyl ether acetate was added and the mixture was cooled to room temperature, after which 35.8 parts of succinic anhydride was added and the reaction was continued at 60°C for 10 hours, and 257.5 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-3. The physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0111] Example 4 Synthesis of alkali-soluble resin solution A-4 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 129.1 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 26.8 parts of dimethylolpropionic acid and 31.3 parts of acrylic acid were added and an addition reaction was carried out. An additional 0.4 parts of triphenylphosphine was added one hour after the addition of acrylic acid, and the temperature was raised to 120 ° C. and the reaction was continued for another 5 hours, completing the dimethylolpropionic acid and acrylic acid addition reaction. Thereafter, 86 parts of propylene glycol monomethyl ether acetate was added and cooled to room temperature, after which 56.9 parts of tetrahydrophthalic anhydride was added and the reaction was continued at 60°C for 10 hours, and 268.9 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-4. Various physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0112] Example 5 Synthesis of alkali-soluble resin solution A-5 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 112.4 parts of propylene glycol monomethyl ether acetate, 187 parts of biphenyl-type epoxy resin YX4000 (manufactured by Mitsubishi Chemical, epoxy equivalent 187 g / equivalent), 0.4 parts of triphenylphosphine as a reaction catalyst, 0.2 parts of Antage W-400 as a polymerization inhibitor were charged, and the temperature was heated to 110 ° C. While maintaining the same temperature, 26.8 parts of dimethylolpropionic acid and 34.6 parts of acrylic acid were added, and an addition reaction was carried out. An additional 0.4 parts of triphenylphosphine was added one hour after the addition of acrylic acid, and the temperature was raised to 120 ° C. and the reaction was continued for another 6 hours, completing the dimethylolpropionic acid and acrylic acid addition reaction. Thereafter, 74.9 parts of propylene glycol monomethyl ether acetate was added and the mixture was cooled to room temperature, after which 32.6 parts of succinic anhydride was added and the reaction was continued at 60°C for 10 hours, and 234.2 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-5. Various physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0113] Example 6 Synthesis of alkali-soluble resin solution A-6 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 118.8 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 20.1 parts of dimethylolpropionic acid and 40.4 parts of acrylic acid were added and an addition reaction was carried out. An additional 0.4 parts of triphenylphosphine was added one hour after the addition of acrylic acid, and the temperature was raised to 120 ° C. and the reaction was continued for another 6 hours, completing the dimethylolpropionic acid and acrylic acid addition reaction. Thereafter, 79.2 parts of propylene glycol monomethyl ether acetate was added and cooled to room temperature, after which 28.8 parts of succinic anhydride and 0.4 parts of triethylamine as a reaction catalyst were added and the reaction was continued for 5 hours at 60°C, and 247.4 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-6. Various physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0114] Example 7 Synthesis of alkali-soluble resin solution A-7 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 115 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 14.8 parts of dimethylolpropionic acid and 44.7 parts of acrylic acid were added and an addition reaction was carried out. An additional 0.4 parts of triphenylphosphine was added one hour after the addition of acrylic acid, and the temperature was raised to 120 ° C. and the reaction was continued for another 6 hours, completing the dimethylolpropionic acid and acrylic acid addition reaction. Thereafter, 76.7 parts of propylene glycol monomethyl ether acetate was added and the mixture was cooled to room temperature, after which 20.5 parts of succinic anhydride was added and the reaction was continued at 60°C for 9 hours, and 239.6 parts of propylene glycol monomethyl ether acetate was added to obtain alkali-soluble resin solution A-7. Various physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0115] Example 8 Synthesis of alkali-soluble resin solution A-8 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 123 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 20.1 parts of dimethylolpropionic acid and 49.9 parts of methacrylic acid were added and an addition reaction was carried out. An additional 0.4 parts of triphenylphosphine was added one hour after the addition of methacrylic acid, and the temperature was raised to 120 ° C. and the reaction was continued for another 6 hours, completing the dimethylolpropionic acid and methacrylic acid addition reaction. Thereafter, 82 parts of propylene glycol monomethyl ether acetate was added and the mixture was cooled to room temperature, after which 29.8 parts of succinic anhydride was added and the reaction was continued at 60°C for 10 hours, and 256.2 parts of propylene glycol monomethyl ether acetate was added to obtain an alkali-soluble resin solution A-8. The physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0116] Comparative Example 1 Synthesis of Comparative Alkali-Soluble Resin Solution B-1 In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet, 129.7 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor were charged and heated to 110 ° C. While maintaining the same temperature, 26.8 parts of dimethylolpropionic acid and 58.4 parts of acrylic acid were added and an addition reaction was carried out. One hour after the addition of acrylic acid, an additional 0.4 parts of triphenylphosphine was added, and the temperature was raised to 120 ° C. and the reaction was continued for another 7 hours, completing the dimethylolpropionic acid and acrylic acid addition reaction. Thereafter, 86.5 parts of propylene glycol monomethyl ether acetate was added and the mixture was cooled to room temperature. Then, 31.5 parts of succinic anhydride was added and the reaction was continued at 60°C for 9 hours, and 270.2 parts of propylene glycol monomethyl ether acetate was added. A comparative alkali-soluble resin solution B-1 having substantially no epoxy groups was obtained. The physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0117] Comparative Example 2 Synthesis of Comparative Alkali-Soluble Resin Solution B-2 A reaction vessel equipped with a thermometer, a stirrer, a gas inlet, a cooling tube, and a dropping tank inlet was charged with 115 parts of propylene glycol monomethyl ether acetate, 207.6 parts of the same cresol novolac epoxy resin YDCN-704A used in Example 1, 0.4 parts of triphenylphosphine as a reaction catalyst, and 0.3 parts of Antage W-400 as a polymerization inhibitor, and heated to 110 ° C. While maintaining the same temperature, 52.1 parts of acrylic acid were added and an addition reaction was carried out. One hour after the addition of acrylic acid, an additional 0.4 parts of triphenylphosphine was added, and the temperature was raised to 120 ° C. and the reaction was continued for a further 5 hours, completing the acrylic acid addition reaction. Thereafter, 76.7 parts of propylene glycol monomethyl ether acetate was added and cooled to room temperature, after which 27.9 parts of succinic anhydride and 0.5 parts of triethylamine were added and the reaction was continued at 60°C for 10 hours, and then 239.7 parts of propylene glycol monomethyl ether acetate was added to obtain comparative alkali-soluble resin solution B-2. Various physical properties of the obtained alkali-soluble resin are shown in Table 1.

[0118]

[0119] Examples 9 to 16, Comparative Examples 3 and 4 The photosensitive resin compositions of Examples 9 to 16 and Comparative Examples 3 and 4 were prepared by mixing the alkali-soluble resins A-1 to A-8 synthesized in Examples 1 to 8 and the comparative alkali-soluble resin solutions B-1 and B-2 synthesized in Comparative Examples 1 and 2 with a polymerizable compound (polyfunctional monomer), photopolymerization initiator, etc. in the formulations shown in Table 2. Table 2 shows the results of evaluation of various properties of the obtained photosensitive resin compositions.

[0120]

[0121] Table 2 reveals that photosensitive resin compositions containing alkali-soluble resins with specific structures and epoxy equivalents of 50,000 g / eq or less exhibit good alkali solubility and photocurability, and furthermore, yield cured products with excellent solvent resistance even under low-temperature curing conditions of 90°C. Furthermore, the photosensitive resin compositions of Examples 11, 12, and 16 exhibited particularly excellent solvent resistance, suggesting that the use of methacrylic acid as the unsaturated monocarboxylic acid and tetrahydrophthalic anhydride as the polybasic acid anhydride results in more pronounced solvent resistance, and that the alkali-soluble resin possessing an alkyl group and a cyclic structure provides even more advantageous properties. Furthermore, among the photosensitive resin compositions of Examples 9 to 16, those in which only a tertiary phosphine (triphenylphosphine) was used as the synthesis catalyst in synthesizing the alkali-soluble resin (Examples 9 to 13, 15, and 16) also exhibited good storage stability. Furthermore, as shown in Example 6, the addition of a tertiary amine (triethylamine) during the addition of the polybasic acid anhydride in the synthesis of the alkali-soluble resin improved reaction efficiency and shortened the process. On the other hand, the compositions of Comparative Examples 3 and 4, which used B-1, which had substantially no epoxy groups, and B-2, which did not use a monobasic acid having a hydroxyl group (dimethylolpropionic acid), showed poor solvent resistance after heat treatment at 90°C. This is thought to be because an ester bond between the epoxy group and the carboxyl group was not formed, or the esterification reaction was inefficient.

[0122] The photosensitive resin composition of the present invention has excellent curability and alkali developability and is suitable as a resist for forming members in the electronic information field, such as a plating resist or a color filter resist. Because of its excellent solvent resistance, the composition is particularly suitable for forming pixels (colored layers) in color filters.

Claims

1. At least one epoxy group-containing structure selected from the structure represented by the following formula (1) and the structure represented by the following formula (2), At least one carboxyl group-containing structure selected from structures represented by the following formulas (3) to (4'), and at least one polymerizable unsaturated bond-containing structure selected from the structure represented by the following formula (5) and the structure represented by the following formula (5′), The epoxy equivalent is 50,000 g / equivalent or less, An alkali-soluble resin having a double bond equivalent of 400 to 1000 g / equivalent. 【Chemistry 1】 In formulas (2), (3′), (4′) and (5′), m is an integer from 1 to 10. In formulas (3) and (3′), R １ are the same or different and each represents a divalent organic group. ２ and R ３ are the same or different and are a hydrogen atom or a group represented by formula (6), R ２ At least one of R is a group represented by formula (6). ４ are the same or different and each represents a trivalent organic group. ５ , R ６ and R ７ are the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. ８ , R ９ are the same or different and each represents a direct bond or a divalent organic group. １０ represents a divalent organic group.

2. 2. The alkali-soluble resin according to claim 1, which has an acid value of 30 to 200 mgKOH / g.

3. A photosensitive resin composition comprising the alkali-soluble resin according to claim 1, a polymerizable compound, and a photopolymerization initiator.

4. A cured product obtained by curing the alkali-soluble resin according to claim 1 or 2, or the photosensitive resin composition according to claim 3.

5. A member for a display device, comprising the cured product according to claim 4 .

6. A display device comprising the member for a display device according to claim 5 .

7. A method for producing an alkali-soluble resin, comprising the steps of: The production method includes a first step of reacting an epoxy resin (a) having two or more epoxy groups in one molecule with a monobasic acid (b) having a primary alcoholic hydroxyl group and an unsaturated monocarboxylic acid (c); A second step of reacting the reaction product obtained in the first step with a polybasic acid anhydride (d), The method for producing an alkali-soluble resin is characterized in that the amounts of the monobasic acid (b) having a primary alcoholic hydroxyl group and the unsaturated monocarboxylic acid (c) used in the first step are adjusted so that the resulting alkali-soluble resin has an epoxy equivalent of 50,000 g / equivalent or less and a double bond equivalent of 400 to 1,000 g / equivalent.

8. A method for producing a photosensitive resin composition, comprising the steps of: The method includes the steps of producing an alkali-soluble resin by the method for producing an alkali-soluble resin according to claim 7, and mixing the obtained alkali-soluble resin having an epoxy equivalent of 50,000 g / equivalent or less and a double bond equivalent of 400 to 1,000 g / equivalent, a polymerizable compound, and a photopolymerization initiator.

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