Alkali-soluble resin, photosensitive resin composition, cured product, and method for producing alkali-soluble resin

Abstract

To provide an alkali-soluble resin which is excellent in developability and can give a low dielectric cured product, and a photosensitive resin composition.SOLUTION: An alkali-soluble resin has a constitutional unit (A) represented by a general formula (1), and a constitutional unit (B) derived from an aromatic vinyl-based monomer, and has an acid value of 20 mgKOH / g or more. In the formula, R1, R2 and R3 are the same or different, and represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a group represented by -R5-COOR6, and any one of R1 to R3 is a group represented by -R5-COOR6. R4 represents a direct bond, or an alkylene group having 1 to 3 carbon atoms. R5 represents a direct bond, or an alkylene group having 1 to 3 carbon atoms. R6 represents a hydrogen atom, or an organic group having 1 to 20 carbon atoms (excluding polymerizable unsaturated group).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an alkali-soluble resin, a photosensitive resin composition, a cured product, and a method for producing the alkali-soluble resin. More specifically, the present invention relates to an alkali-soluble resin, a photosensitive resin composition, a cured product, and a method for producing the alkali-soluble resin, which are excellent in developability and can give a cured product with low dielectric properties. [Background technology]

[0002] Conventionally, various resins and resin compositions having properties according to various applications have been developed for various optical components and electric / electronic devices, such as color filters, inks, printing plates, printed wiring boards, semiconductor devices, photoresists, organic insulating films, and organic protective films used in liquid crystal displays and solid-state imaging devices. In recent years, optical components and electric / electronic devices have become smaller, thinner, and more energy-efficient, and as a result, higher quality performance is required for the various components used. In order to meet such demands, further research is being conducted on resins and resin compositions that are materials for various components.

[0003] To date, various resins have been developed to meet a variety of needs. For example, Patent Document 1 describes a maleimide copolymer obtained by polymerizing monomer components including an N-substituted maleimide monomer, an aromatic vinyl monomer, and an unsaturated monocarboxylic acid monomer as a resin having excellent heat resistance, flow thermal stability, and alkali solubility, the maleimide copolymer having an alkaline aqueous solution insoluble content of 10% or less and a content of a compound having a specific structure of 10% or less. Patent Document 2 describes a polymer obtained by polymerizing an N-substituted maleimide monomer and / or a compound having a specific structure which is an ether dimer of a 2-(hydroxyalkyl)acrylic acid ester, vinyl toluene, and a monomer having an acid group as a resin having excellent heat resistance and alkaline developability and having a high dissolution rate in organic solvents and alkalis.

[0004] Furthermore, for example, Patent Document 3 describes a copolymer having a specific norbornene structure as a resin that suppresses pattern deformation when a photosensitive resin composition is cured, and the polymer has a peak area at a molecular weight of 1000 or less in a molecular weight distribution curve obtained by GPC of 1% or less of the total. Patent Document 4 describes an acid-sensitive polymer containing a specific norbornene structure as a polymer for a resist. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-30119 A [Patent Document 2] JP 2009-40999 A [Patent Document 3] JP 2017-101247 A [Patent Document 4] JP 2002-327021 A Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the frequency of electric and electronic devices, such as communication devices such as mobile phones and electronic devices such as computers, has increased, and materials used in these electric and electronic devices are required to have low dielectric constants in order to reduce transmission loss. However, conventional alkali-soluble resins have not yet been able to fully meet the demand for low dielectric constants. In addition, such materials are also required to have good developability, especially when used as resists.

[0007] In view of the above-mentioned current situation, an object of the present invention is to provide an alkali-soluble resin and a photosensitive resin composition which are excellent in developability and capable of giving a cured product with low dielectric properties. [Means for solving the problem]

[0008] The present inventors have conducted extensive research into resins used in photosensitive resin compositions and have found that a resin having a specific structural unit having a carboxy group and a structural unit derived from an aromatic vinyl monomer, and having an acid value within a specific range, can provide a cured product that has excellent developability and low dielectric properties, and has thus completed the present invention.

[0009] That is, the present invention provides the following aspects. [1] An alkali-soluble resin having a structural unit (A) represented by the following general formula (1) and a structural unit (B) derived from an aromatic vinyl monomer, and having an acid value of 20 mgKOH / g or more:

[0010] [ka]

[0011] (In the formula, R 1 , R 2 and R 3 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or -R 5 -COOR 6 R represents a group represented by 1 ~R 3 One of the following is -R 5 -COOR 6 R is a group represented by the formula: 4 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 5 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 6 represents a hydrogen atom or an organic group having 1 to 20 carbon atoms (excluding polymerizable unsaturated groups). [2] The alkali-soluble resin according to the above [1], further comprising a structural unit (C) having a main chain ring structure. [3] The alkali-soluble resin according to [2] above, wherein the structural unit (C) having a main chain ring structure is at least one selected from the group consisting of a structural unit derived from an N-substituted maleimide, a structural unit derived from a dialkyl-2,2'-(oxydimethylene)diacrylate monomer, and a structural unit derived from an unsaturated dicarboxylic acid anhydride. [4] The alkali-soluble resin according to any one of the above [1] to [3], characterized in that the content of the structural unit (A) is 5 to 70 mass % relative to 100 mass % of all structural units of the alkali-soluble resin, and the content of the structural unit (B) is 3 to 90 mass % relative to 100 mass % of all structural units of the alkali-soluble resin. [5] The alkali-soluble resin according to any one of the above [2] to [4], wherein the content of the structural unit (C) is 1 to 60 mass % relative to 100 mass % of all structural units of the alkali-soluble resin. [6] The alkali-soluble resin according to any one of the above [1] to [5], having a weight average molecular weight of 4,000 to 100,000. [7] The alkali-soluble resin according to any one of the above [1] to [6], which has a polymerizable double bond in a side chain. [8] The alkali-soluble resin according to any one of [1] to [7] above, wherein the structural unit (A) is a structural unit derived from maleic acid. [9] The alkali-soluble resin according to any one of [1] to [8] above, which is a polymer for use in a negative resist.

[10] A photosensitive resin composition comprising the alkali-soluble resin according to any one of [1] to [9] above, a photopolymerization initiator, and a polymerizable compound.

[11] A cured product obtained by curing the alkali-soluble resin described in any one of [1] to [9] above or the photosensitive resin composition described in

[10] above.

[12] A method for producing an alkali-soluble resin, comprising a step of polymerizing a monomer component containing a monomer (a) represented by the following general formula (2) and an aromatic vinyl monomer (b):

[0012] [ka]

[0013] (In the formula, R 1 , R 2 and R 3 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or -R 5 -COOR 6 R represents a group represented by 1 ~R 3 One of the following is -R 5 -COOR 6 R is a group represented by the formula: 4 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 5 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 6 represents a hydrogen atom or an organic group having 1 to 20 carbon atoms (excluding polymerizable unsaturated groups). Effect of the Invention

[0014] The alkali-soluble resin of the present invention and the photosensitive resin composition containing the same are capable of providing a cured product having excellent developability and low dielectric properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The preferred embodiments of the present invention are specifically described below, but the present invention is not limited to the following description, and can be modified as appropriate within the scope of the present invention. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the 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".

[0016] 1. Alkali-soluble resin The alkali-soluble resin of the present invention is characterized by having a structural unit (A) represented by the above general formula (1) and a structural unit (B) derived from an aromatic vinyl monomer, and having an acid value of 20 mgKOH / g or more. In the present invention, the term "structural unit" refers to a repeating (structural) unit in the polymer structure of the alkali-soluble resin.

[0017] The reason why the alkali-soluble resin of the present invention can provide a cured product with excellent developability and low dielectric properties is believed to be due to the following reasons. That is, the structural unit (A) represented by the above general formula (1) closes a ring during heat curing to form an anhydride. This causes the acid component with a biased charge to disappear, and the dielectric constant of the resulting cured product becomes low. On the other hand, before heat curing, the resin has a carboxy group and an acid value within a predetermined range, so that the resin is alkali-soluble and can exhibit good developability. In addition, the monomer into which the structural unit (A) can be introduced has low polymerizability, but by polymerizing it together with an aromatic vinyl monomer, the polymerizability becomes good, and it is believed to be easy to design a desired polymer structure. The alkali-soluble resin of the present invention will be described in detail below.

[0018] (Structural unit (A)) The structural unit (A) represented by the above general formula (1) has a structure that undergoes ring closure upon heating. By having the structural unit (A), the resin has alkali solubility during development and exhibits good developability, while during post-curing (post-baking), the ring is closed by heating, and the acid component (carboxy group) with biased charge disappears, so that a cured product with a low dielectric constant can be obtained.

[0019] In the above general formula (1), R 1 , R 2 and R 3 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or -R 5 -COOR 6 R represents a group represented by 1 ~R 3 One of the following is -R 5 -COOR 6 It is a group represented by the following formula:

[0020] R 1 , R 2 or R 3 The number of carbon atoms in the alkyl group represented by the following formula is preferably 1 to 5, and more preferably 1 to 3, in terms of facilitating ring closure.

[0021] R 5 represents a direct bond or an alkylene group having 1 to 3 carbon atoms, and preferably represents a direct bond. R 6 represents a hydrogen atom or an organic group having 1 to 20 carbon atoms (excluding polymerizable unsaturated groups).

[0022] R 6 Examples of the organic group represented by the formula (I) include a hydrocarbon group which may have a substituent other than a polymerizable unsaturated group, and a monovalent group consisting of a combination of a hydrocarbon group which may have a substituent and -O-, -CO-, -NH-, -SO-, or -SO2-. The organic group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1 to 8 carbon atoms, and particularly preferably 2 to 6 carbon atoms.

[0023] The hydrocarbon group may be linear or cyclic, and may be saturated or unsaturated. The hydrocarbon group may be a monovalent or divalent aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group. Of these, an aliphatic hydrocarbon group or an alicyclic hydrocarbon group is preferred, and an aliphatic hydrocarbon group is more preferred.

[0024] Examples of the aliphatic hydrocarbon group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, s-butyl, pentyl, isopentyl, neopentyl, and hexyl groups; alkenyl groups such as vinyl, n-propenyl, isopropenyl, and 1-butenyl groups; and divalent groups thereof.

[0025] Examples of the alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group; a dicyclopentanyl group, a norbornyl group, an adamantyl group, and divalent groups thereof.

[0026] Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an ethylphenyl group, a tolyl group, a xylyl group, and divalent groups thereof.

[0027] Examples of the substituent on the hydrocarbon group include a methoxy group and a halogen atom.

[0028] Examples of the polymerizable unsaturated group include a (meth)acryloyl group, a vinyl group, an allyl group, and a methallyl group. 6 The organic group represented by the formula (I) does not contain a polymerizable unsaturated group.

[0029] Among them, R 6 The organic group represented by the formula (I) is preferably a saturated hydrocarbon group or a group formed by combining a saturated hydrocarbon group with -O-.

[0030] The group formed by a combination of the above-mentioned saturated hydrocarbon group and -O- may be a group formed by a combination of a monovalent saturated hydrocarbon group and -O-, or may be a group formed by a combination of a monovalent saturated hydrocarbon group, a divalent saturated hydrocarbon group, and -O-.

[0031] The monovalent saturated hydrocarbon group includes an alkyl group and a cycloalkyl group, and among these, an alkyl group is preferable. Examples of the divalent saturated hydrocarbon group include an alkylene group and a cycloalkylene group, and among these, an alkylene group is preferred.

[0032] Among them, the group consisting of the combination of the above-mentioned saturated hydrocarbon group and -O- is preferably -R a1 -OR a2 A group represented by R a1 R represents a divalent saturated hydrocarbon group.a2 represents a monovalent saturated hydrocarbon group.) is preferred. The saturated hydrocarbon group may be linear or branched. R a1 The divalent saturated hydrocarbon group represented by the following formula (I) is preferably an alkylene group having 1 to 19 carbon atoms, and more preferably an alkylene group having 1 to 11 carbon atoms. R a2 The monovalent saturated hydrocarbon group represented by the following formula (I) is preferably an alkyl group having 1 to 19 carbon atoms, and more preferably an alkyl group having 1 to 11 carbon atoms.

[0033] R 1 ~R 3 One of the following is -R 5 -COOR 6 R is a group represented by the formula: 1 ~R 3 One of the following is -R 5 -COOR 6 When the group is represented by the formula: 3 But -R 5 -COOR 6 When the group is a group represented by the formula: 4 -COOH can be used to close a ring when heated. 1 or R 2 But -R 5 -COOR 6 When a plurality of structural units (A) are adjacent to each other, -R 5 -COOR 6 and -R of another structural unit (A) 5 -COOR 6 In particular, R is preferred because it is easy to close the ring when heated and can more easily give a cured product with low dielectric properties. 2 or R 3 -R 5 -COOR 6 Preferably, R is a group represented by 3 -R 5 -COOR 6 It is more preferable that the group is a group represented by the following formula:

[0034] R 4 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 4 preferably represents a direct bond in that it is easy to close a ring.

[0035] The alkali-soluble resin having the structural unit (A) can be obtained by polymerizing a monomer component containing a monomer that gives the structural unit (A), or by copolymerizing a carboxylic acid anhydride and then adding a compound such as an alcohol compound to perform half-esterification.

[0036] The monomer that gives the structural unit (A) is not particularly limited as long as it is a monomer that can be polymerized to form the structural unit (A). For example, a monomer (a) represented by the following general formula (2) can be mentioned.

[0037] [ka]

[0038] (In the formula, R 1 , R 2 , R 3 and R 4 is the same as the above general formula (1). Specific examples of the monomer (a) include unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid, and monoesters thereof (unsaturated dicarboxylic acid monoesters).

[0039] Examples of the unsaturated dicarboxylic acid monoester include monoesters of the above-mentioned unsaturated dicarboxylic acids with alcohols or glycol ethers.

[0040] Examples of the alcohols include methanol, ethanol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexanol, ethylene glycol, and diethylene glycol. The alcohols preferably have 1-20 carbon atoms, more preferably 2-12 carbon atoms, and even more preferably 3-10 carbon atoms.

[0041] Examples of the glycol monoethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and 3-methoxybutanol. The glycol monoethers preferably have 1-20 carbon atoms, more preferably 2-12 carbon atoms, and even more preferably 3-10 carbon atoms.

[0042] Among them, the unsaturated dicarboxylic acid monoester is preferably a monoester of the above-mentioned unsaturated dicarboxylic acid and an alcohol having 1 to 4 carbon atoms, and more preferably a monoester of the above-mentioned unsaturated dicarboxylic acid and an alkyl alcohol having 1 to 4 carbon atoms.

[0043] Among these, maleic acid or maleic acid monoester is preferred, and maleic acid is more preferred, in that it can give a cured product with even lower dielectric properties. The above structural unit (A) is preferably a structural unit derived from maleic acid.

[0044] The alkali-soluble resin may have one or more types of the structural unit (A).

[0045] The content of the structural unit (A) is preferably 5 to 70 mass %, more preferably 10 to 60 mass %, and even more preferably 15 to 50 mass %, relative to 100 mass % of all structural units in the alkali-soluble resin.

[0046] (Structural unit (B)) The alkali-soluble resin of the present invention has a structural unit (B) derived from an aromatic vinyl monomer. By having the structural unit (B), the dielectric constant of the obtained cured product can be reduced. In addition, the polymerizability of the monomer during resin production is improved, making it easier to design a desired polymer. Conventionally, monomers that provide the above structural unit (A), such as maleic acid, have low polymerizability and are not easily polymerized with, for example, an N-substituted maleimide monomer, but by using an aromatic vinyl monomer, the polymerizability is improved and it is easier to design a desired polymer.

[0047] The alkali-soluble resin having the above-mentioned structural unit (B) can be obtained by polymerizing a monomer component containing an aromatic vinyl monomer (b). The aromatic vinyl monomer (b) may be a polymerizable monomer having an aromatic group and a vinyl group.

[0048] The aromatic group includes groups containing a benzene ring, a naphthalene ring, etc., and among these, groups containing a benzene ring are preferred. These rings may have one or more substituents. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, etc.

[0049] Specific examples of the aromatic vinyl monomer (b) include styrene, vinyltoluene, α-methylstyrene, xylene, methoxystyrene, ethoxystyrene, etc. Among these, styrene and vinyltoluene are preferred because of their excellent thermal decomposition resistance, and vinyltoluene is more preferred because of their high dissolution rate in organic solvents and alkalis.

[0050] The alkali-soluble resin may have one or more types of the structural unit (B).

[0051] The content of the structural unit (B) is preferably 3 to 90 mass%, more preferably 10 to 60 mass%, even more preferably 15 to 55 mass%, and still more preferably 20 to 50 mass%, relative to 100 mass% of all structural units of the alkali-soluble resin.

[0052] (Structural unit (C)) The alkali-soluble resin of the present invention preferably further contains a structural unit (C) having a main chain ring structure. By containing the structural unit (C), heat resistance can be improved.

[0053] Examples of the ring structure include an imide ring, a tetrahydropyran ring, a tetrahydrofuran ring, a lactone ring, and a norbornene ring.

[0054] A copolymer having the above-mentioned structural unit (C) can be obtained by polymerizing a monomer component that includes a monomer capable of introducing a ring structure into the main chain.

[0055] Examples of the monomer capable of introducing a ring structure into the main chain include a monomer having a double bond-containing ring structure in the molecule, a monomer that forms a polymer having a ring structure in the main chain by cyclic polymerization, and a monomer that forms a ring structure after polymerization.Specific examples of the monomer that can improve heat resistance include at least one monomer selected from the group consisting of N-substituted maleimide monomers, dialkyl-2,2'-(oxydimethylene) diacrylate monomers, and unsaturated dicarboxylic anhydrides.That is, the structural unit (C) is preferably at least one structural unit selected from the group consisting of N-substituted maleimide monomer-derived structural units, dialkyl-2,2'-(oxydimethylene) diacrylate monomer-derived structural units, and unsaturated dicarboxylic anhydrides-derived structural units. Among these, as the monomer capable of introducing a ring structure into the main chain, an N-substituted maleimide monomer is preferred, since it can lower the dielectric tangent of the cured product and further improve the heat resistance.

[0056] Examples of the N-substituted maleimide monomer include N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, Nt-butylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, and N-naphthylmaleimide, and one or more of these can be used. Among these, from the viewpoint of heat resistance, N-phenylmaleimide, N-benzylmaleimide, and N-cyclohexylmaleimide are preferred, and N-benzylmaleimide is more preferred.

[0057] Examples of the N-benzylmaleimide include benzylmaleimide; alkyl-substituted benzylmaleimides such as p-methylbenzylmaleimide and p-butylbenzylmaleimide; phenolic hydroxyl group-substituted benzylmaleimides such as p-hydroxybenzylmaleimide; and halogen-substituted benzylmaleimides such as o-chlorobenzylmaleimide, o-dichlorobenzylmaleimide and p-dichlorobenzylmaleimide.

[0058] Examples of the dialkyl-2,2'-(oxydimethylene) diacrylate monomer include dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, diethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, di(n-propyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, and dialkyl-2,2'-(oxydimethylene) diacrylate monomers described in paragraph

[0044] of JP-A-2022-028533. Among these, dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate is more preferred from the viewpoints of transparency, dispersibility, ease of industrial availability, and the like.

[0059] Examples of the unsaturated dicarboxylic anhydride include maleic anhydride, citraconic anhydride, mesaconic anhydride, itaconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, allylsuccinic anhydride, cis-4-cyclohexene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, etc. Among these, maleic anhydride is preferred because of its good heat-resistant coloration.

[0060] Examples of monomers that can introduce a ring structure into the main chain include α-(unsaturated alkoxyalkyl)acrylate monomers and 2-(hydroxyalkyl)acrylic acid alkyl esters described in paragraphs

[0045] to

[0048] of JP-A-2022-28533.

[0061] The alkali-soluble resin may have one or more types of the structural unit (C).

[0062] From the viewpoint of low dielectric constant and heat resistance, the content of the structural unit (C) is preferably 1 to 60 mass%, more preferably 5 to 55 mass%, and even more preferably 10 to 50 mass%, relative to 100 mass% of all structural units of the alkali-soluble resin.

[0063] (Structural unit (D)) The alkali-soluble resin may contain a structural unit (D) other than the above-mentioned structural units (A), (B) and (C). Examples of the structural unit (D) include structural units derived from the following monomers. Acid group-containing monomers other than the above-mentioned unsaturated dicarboxylic acids, unsaturated dicarboxylic acid monoesters, and unsaturated dicarboxylic acid anhydrides, such as unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, cinnamic acid, and vinylbenzoic acid; and phosphate group-containing unsaturated compounds such as Light Ester P-1M (manufactured by Kyoeisha Chemical Co., Ltd.). Hydroxyl group-containing monomers such as hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2,3-hydroxypropyl (meth)acrylate.

[0064] Methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-amyl (meth)acrylate, s-amyl (meth)acrylate, t-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, tridecyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (meth)acrylic acid 4-(1-methoxy)ethoxycyclohexyl, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, 1,4-dioxaspiro[4,5]dec-2-yl methacrylic acid, (meth)acryloylmorpholine, 4-(meth)acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, p) (meth)acrylic acid ester monomers such as acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2-methyl-2-cyclohexyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2,2-dimethyl-1,3-dioxolane, acetoacetoxyethyl (meth)acrylate, and monomers having an active methylene group described in JP2016-29151A.

[0065] Epoxy group-containing monomers such as glycidyl (meth)acrylate, β-methyl glycidyl (meth)acrylate, β-ethyl glycidyl (meth)acrylate, vinylbenzyl glycidyl ether, allyl glycidyl ether, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and vinylcyclohexene oxide. Isocyanate group-containing monomers such as isocyanatoethyl (meth)acrylate, 2-methacryloyloxyethyl isocyanate, and allyl isocyanate. Amino group-containing monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, and 2-butylaminoethyl (meth)acrylate.

[0066] (Meth)acrylamides such as N,N-dimethyl(meth)acrylamide and N-methylol(meth)acrylamide. Macromonomers having a (meth)acryloyl group at one end of the polymer molecular chain, such as polystyrene, polymethyl (meth)acrylate, polyethylene oxide, polypropylene oxide, polysiloxane, polycaprolactone, and polycaprolactam. Conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene. Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate.

[0067] Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, 2-hydroxyethyl vinyl ether, and 4-hydroxybutyl vinyl ether. N-vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinylmorpholine, and N-vinylacetamide.

[0068] The structural unit (D) is, in the general formula (1), R 6 Such a structural unit has a polymerizable unsaturated group in a side chain.

[0069] Further, examples of the structural unit (D) include a structural unit represented by the following general formula (3).

[0070] [ka]

[0071] (In the formula, R 7 , R 8 , and R 9 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, -R 11 -COSR 12 , or -R 11 -CONHR 13 R represents a group represented by 7 ~R 9 One of the following is -R 11 -COSR 12 , or -R 11 -CONHR 13 R is a group represented by the formula: 10 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 11 R represents a direct bond or an alkylene group having 1 to 3 carbon atoms. 12 and R 13 are the same or different and represent an organic group having 1 to 20 carbon atoms.

[0072] R 12 and R 13 The organic group having 1 to 20 carbon atoms represented by the above-mentioned R 6 In addition to the organic group represented by the following formula, polymerizable unsaturated groups can be mentioned. When the alkali-soluble resin contains a structural unit (D) having a polymerizable unsaturated group in the side chain, the photocurability is improved.

[0073] When the structural unit (D) contains a structural unit having an ester bond or an ether bond, the development speed can be improved and the cured product can be given flexibility. On the other hand, from the viewpoint of lowering the dielectric constant and the dielectric loss tangent and improving the heat resistance, it is preferable that the number of structural units having an ester bond or an ether bond is small.

[0074] The alkali-soluble resin may have one or more types of the structural unit (D).

[0075] From the viewpoints of low dielectric constant, low dielectric tangent, heat resistance, developability, etc., the content of the structural unit (D) is preferably 1 to 60 mass %, more preferably 3 to 50 mass %, even more preferably 5 to 40 mass %, and still more preferably 10 to 30 mass %, relative to 100 mass % of all structural units of the alkali-soluble resin.

[0076] Moreover, it is preferable that the alkali-soluble resin does not have an acid-sensitive functional group (acid-labile group), since if the resin has an acid-sensitive functional group, it may not be usable as a negative type resin. The acid-sensitive functional group is a group which reacts in response to an acid, and examples thereof include a group represented by -C(=O)-XR (X represents an oxygen atom, a sulfur atom, -NH-, -NHSO2- or -NHSO2NH-; R represents a tertiary alkyl group such as a t-butyl group or a t-amyl group; an isobornyl group; a 1-alkoxyethyl group such as a 1-ethoxyethyl group, a 1-butoxyethyl group, a 1-isobutoxyethyl group or a 1-cyclohexyloxyethyl group; an alkoxymethyl group such as a 1-methoxymethyl group or a 1-ethoxymethyl group; a tetrahydropyranyl group, a tetrahydrofuranyl group, a trialkylsilyl ester group, a 3-oxocyclohexyl ester group, etc.).

[0077] The above alkali-soluble resin has an acid value of 20 mgKOH / g or more. By using an alkali-soluble resin having the above acid value, the developability and low dielectric properties are improved. The acid value of the above alkali-soluble resin is preferably 20 to 700 mgKOH / g, more preferably 50 to 500 mgKOH / g, even more preferably 100 to 450 mgKOH / g, and even more preferably 100 to 400 mgKOH / g, in terms of good developability. The acid value is a value obtained by measurement by neutralization titration using a potassium hydroxide (KOH) solution, and is an acid value per 1 g of resin solid content.

[0078] The weight average molecular weight of the alkali-soluble resin is preferably 4,000 to 100,000, more preferably 6,000 to 70,000, and further preferably 8,000 to 40,000. The weight average molecular weight can be measured by gel permeation chromatography (GPC), specifically, by the method described in the Examples.

[0079] The alkali-soluble resin may have a polymerizable double bond (carbon-carbon double bond) in the side chain. By having a polymerizable double bond in the side chain, the photocurability of the resin can be improved. The polymerizable double bond may be the same as the above-mentioned polymerizable unsaturated group, and among them, a (meth)acryloyl group is preferable.

[0080] When the alkali-soluble resin has a polymerizable double bond in a side chain, from the viewpoints of low dielectric properties and developability, the double bond equivalent of the alkali-soluble resin is preferably 200 to 20,000 g / equivalent, more preferably 250 to 15,000 g / equivalent, and even more preferably 300 to 10,000 g / equivalent.

[0081] The double bond equivalent is the mass of the solid content of the resin solution per 1 mol of polymerizable double bonds of the alkali-soluble resin. The mass of the solid content of the resin solution is the mass of the monomer components constituting the resin. The double bond equivalent can be determined by dividing the mass (g) of the resin solid content of the resin solution by the amount (mol) of polymerizable double bonds of the resin. It can also be calculated by measuring the number of ethylenic double bonds contained in 1 g of the alkali-soluble resin in accordance with the test method for iodine value described in JIS K 0070:1992.

[0082] <Method for producing alkali-soluble resin> The method for producing the alkali-soluble copolymer of the present invention is not particularly limited as long as it is a method that can obtain a copolymer having the above-mentioned structural unit (A) and structural unit (B) and an acid value in a predetermined range. For example, a method of polymerizing a monomer component containing a monomer that can introduce each of the above-mentioned structural units, a method of polymerizing a monomer component to obtain a base polymer, and a method of adding another compound to a group possessed by the above-mentioned base polymer to obtain a polymer having a predetermined structural unit, etc. can be mentioned.

[0083] The method for polymerizing the monomer components is not particularly limited, and commonly used techniques such as bulk polymerization, solution polymerization, and emulsion polymerization can be used. Among these, solution polymerization is preferred because it is industrially advantageous and allows easy structural adjustment such as molecular weight. As the polymerization mechanism of the monomer components, a polymerization method based on a mechanism such as radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization can be used, but a polymerization method based on a radical polymerization mechanism is preferred because of its industrial advantages. The molecular weight of the polymer obtained by polymerizing the above-mentioned monomer components can be controlled by appropriately adjusting the amount and type of the polymerization initiator, the polymerization temperature, and the type and amount of the chain transfer agent.

[0084] The polymerization initiator may be a peroxide or an azo compound that is usually used as a polymerization initiator. The chain transfer agent may be a compound having a mercapto group, such as alkyl mercaptans, mercapto carboxylic acids, and mercapto carboxylic acid esters, that are usually used as a chain transfer agent. These may be used alone or in combination of two or more. The amount of these to be added may be appropriately determined by a known method.

[0085] Examples of the solvent used in the polymerization include aromatic hydrocarbon solvents such as toluene, xylene, and benzene; aliphatic hydrocarbon solvents such as hexane, pentane, heptane, and cyclohexane; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; halogenated hydrocarbon solvents such as chlorobenzene, dichloromethane, chloroform, and 1,2-dichloroethane; nitrile solvents such as acetonitrile, propionitrile, and valeronitrile; ester solvents such as methyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; amide solvents such as dimethylformamide (DMF), dimethylacetamide, and N-methylpyrrolidone; Examples of the solvents include ether solvents such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), anisole, diethylene glycol dimethyl ether (diglyme), diethylene glycol ethyl ether (carbitol), cyclopentyl methyl ether (CPME), propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether; fluorine-based solvents such as perfluorohexane, perfluorocyclohexane, pentafluorobenzene, and octafluorotoluene; DMSO, nitromethane, etc. These may be used alone or in combination of two or more.

[0086] The polymerization concentration when polymerizing the monomer composition (reaction liquid) containing the above monomer components is preferably 5 to 90 mass%, more preferably 5 to 70 mass%, and further preferably 10 to 60 mass%. The polymerization concentration is the mass% of the monomer used relative to 100 mass% of the reaction liquid.

[0087] Regarding the polymerization conditions, the polymerization temperature may be appropriately set depending on the type and amount of the monomer used, the type and amount of the polymerization initiator, etc., and is, for example, preferably 50 to 130° C., more preferably 60 to 120° C. Similarly, the polymerization time can also be appropriately set, and is, for example, preferably 1 to 5 hours, more preferably 2 to 4 hours.

[0088] The method for producing the above-mentioned alkali-soluble resin is preferably a method having a step of polymerizing a monomer component containing the above-mentioned general formula (2) (a) and the above-mentioned aromatic vinyl monomer (b).The method for producing an alkali-soluble resin having a step of polymerizing a monomer component containing the above-mentioned general formula (2) (a) and the above-mentioned aromatic vinyl monomer (b) is also one aspect of the present invention.

[0089] When a polymer having a polymerizable double bond in a side chain is produced, the polymer can be produced by polymerization using the monomer (a) and / or an acid group-containing monomer as a monomer component in addition to the monomer (b) in the polymerization step to obtain a polymer having an acid group in the side chain of the polymer (base polymer 1), and then adding a compound having a group reactive with an acid group and a polymerizable double bond to the base polymer 1. Also, the polymer can be produced by polymerization using the monomer (b), the monomer (a) and / or an acid group-containing monomer as a monomer component in addition to the monomer (a) and / or an acid group-containing monomer as a monomer component in the polymerization step to obtain a polymer having a hydroxyl group in the side chain of the polymer (base polymer 2), and then adding a compound having a group reactive with a hydroxyl group and a polymerizable double bond to the base polymer 2.

[0090] Examples of the compound having a group capable of reacting with an acid group and a polymerizable double bond include the above-mentioned epoxy group-containing monomer, isocyanate group-containing monomer, and amino group-containing monomer. Examples of the compound having a group capable of reacting with a hydroxyl group and a polymerizable double bond include the above-mentioned isocyanate group-containing monomers. The above addition reaction is not particularly limited and can be carried out by a known method. In the above addition reaction, a catalyst, a polymerization inhibitor, a solvent, etc. that are usually used may be used.

[0091] In this way, the alkali-soluble resin may have a polymerizable double bond in the side chain, but in the addition reaction, for example, when a hydroxyl group is generated, there is a risk that the electric charge becomes unbalanced and the dielectric constant of the obtained cured product becomes high. In addition, when a side chain is introduced, if the side chain is long, there is a risk that the dielectric constant and dielectric loss tangent become high and that it becomes difficult to close the ring during heat curing.

[0092] In addition, the method for producing the alkali-soluble resin includes, as a monomer component, a monomer (a) represented by the above general formula (2) (wherein R 6 represents a hydrogen atom.) or an acid anhydride thereof and a monomer component containing the aromatic vinyl monomer (b) are polymerized, and the obtained base polymer is reacted with a compound having a group capable of reacting with an acid group to effect half esterification or to introduce a polymerizable double bond into a side chain.

[0093] Examples of the compound having a group capable of reacting with an acid group include compounds having a hydroxyl group such as alcohols, compounds having a thiol group such as n-dodecyl mercaptan and mercaptopropionic acid, the above-mentioned amine group-containing monomers, epoxy group-containing monomers, and isocyanate group-containing monomers.

[0094] The method for producing the alkali-soluble resin may include other steps in addition to the above-mentioned reaction step. Examples of the other steps include an aging step, a neutralization step, a dilution step, a drying step, a concentration step, and a purification step. These steps can be carried out by known methods.

[0095] 2. Photosensitive resin composition The alkali-soluble resin of the present invention can be made into a photosensitive resin composition by combining it with a photopolymerization initiator and a polymerizable compound. Such a photosensitive resin composition containing the above-mentioned alkali-soluble resin, photopolymerization initiator, and polymerizable compound also constitutes one aspect of the present invention. The photosensitive resin composition of the present invention contains the above-mentioned alkali-soluble resin, and therefore can provide a cured product having excellent developability and low dielectric properties. In addition, the photosensitive resin composition of the present invention can provide a cured product having excellent photocurability, heat resistance, and heat-resistant coloration properties.

[0096] In the photosensitive resin composition, the content of the alkali-soluble resin is not particularly limited and may be appropriately set depending on the application and the blending of other components. For example, the content is preferably 5 to 80 mass%, more preferably 10 to 75 mass%, and even more preferably 15 to 70 mass%, relative to 100 mass% of the total solid content of the photosensitive resin composition. In this specification, the term "total solid content" refers to the total amount of components that form the cured product (components excluding the solvent and the curing catalyst that volatilize during the formation of the cured product).

[0097] (Photopolymerization initiator) The photopolymerization initiator is not particularly limited, and known photopolymerization initiators can be used. For example, aminoketone compounds such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one ("IRGACURE907", manufactured by BASF) and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 ("IRGACURE369", manufactured by BASF); benzyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethane-1-one ("IRGACURE651", manufactured by BASF); hydroketone compounds such as 1-hydroxy-cyclohexyl-phenyl-ketone ("IRGACURE184", manufactured by BASF); 1,2-octanedione, Oxime ester compounds such as 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); benzophenone compounds; benzoin compounds; thioxanthone compounds; halomethylated triazine compounds; halomethylated oxadiazole compounds; biimidazole compounds; titanocene compounds; benzoic acid ester compounds; acridine compounds; phosphine oxide compounds; and the like. Examples of photopolymerization initiators include those described in paragraph

[0200] of JP-A-2022-28533. Among them, aminoketone compounds and oxime ester compounds are preferred. The photopolymerization initiator may be used alone or in combination of two or more.

[0098] The content of the photopolymerization initiator is preferably 0.3 to 20 mass %, more preferably 0.5 to 10 mass %, and further preferably 1 to 8 mass %, relative to 100 mass % of the total solid content of the photosensitive resin composition.

[0099] (polymerizable compound) Examples of the polymerizable compound include low molecular weight compounds 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 of the polymerizable compound include monofunctional compounds having one polymerizable unsaturated group in the molecule and polyfunctional compounds having two or more polymerizable unsaturated groups.

[0100] 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, etc. Also usable are monomers having an active methylene group or an active methine group.

[0101] Examples of the polyfunctional compound include 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, and cyclohexanedimethanol di(meth)acrylate; trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and the like. ) acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, and other polyfunctional (meth)acrylate compounds having three or more functional groups, as well as the polymerizable compounds described in paragraphs

[0205] to

[0212] of JP-A-2022-28533. These polymerizable compounds may be used alone or in combination of two or more types.

[0102] Among the above polymerizable compounds, it is preferable to use a polyfunctional polymerizable compound from the viewpoint of further increasing the curability of the photosensitive resin composition. The number of functionalities of the above polyfunctional polymerizable compound is preferably 3 or more, more preferably 4 or more. In addition, the number of functionalities is preferably 10 or less, more preferably 8 or less. The molecular weight of the polymerizable compound is not particularly limited, but is preferably, for example, 2000 or less from the viewpoint of handling.

[0103] As the polyfunctional polymerizable compound, from the viewpoints of reactivity, economic efficiency, availability, etc., preferably, a compound having a (meth)acryloyl group, such as a polyfunctional (meth)acrylate compound, a polyfunctional urethane (meth)acrylate compound, or a (meth)acryloyl group-containing isocyanurate compound, is more preferably, a polyfunctional (meth)acrylate compound. By including a compound having a (meth)acryloyl group, the photosensitive resin composition has better photosensitivity and curability, and a cured product having higher hardness and transparency can be obtained. As the polyfunctional polymerizable compound, it is more preferable to use a polyfunctional (meth)acrylate compound having three or more functional groups.

[0104] The content of the polymerizable compound is preferably 1 to 70 mass %, more preferably 5 to 60 mass %, and further preferably 10 to 50 mass %, relative to 100 mass % of the total solid content of the photosensitive resin composition.

[0105] The photosensitive resin composition may also contain other components other than the above-mentioned components as necessary. Examples of the other components include solvents, coloring materials (pigments, dyes), dispersants, heat resistance improvers, leveling agents, development aids, inorganic particles such as metal oxide particles, coupling agents such as silanes, aluminum, and titanium, thermosetting resins such as fillers, phenolic resins, and polyvinylphenols, polyfunctional epoxy compounds, curing aids such as polyfunctional thiol compounds, plasticizers, polymerization inhibitors, ultraviolet absorbers, antioxidants, matting agents, defoamers, antistatic agents, slip agents, surface modifiers, thixotropic agents, thixotropic aids, quinone diazide compounds, polyhydric phenol compounds, cationic polymerizable compounds, and thermal acid generators. These may be used alone or in combination of two or more. These other components can be appropriately selected from known ones and used, and the amount used can be appropriately set.

[0106] Examples of the polyfunctional epoxy compound include compounds having two epoxy groups, such as polyethylene glycol diglycidyl ether, bisphenol A type diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and glycerin diglycidyl ether; and compounds having three or more epoxy groups, such as trifunctional or higher polyethylene glycol glycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, and polyglycerol polyglycidyl ether. Examples of commercially available products of the polyfunctional epoxy compound include Epolite (trade name) manufactured by Kyoeisha Chemical Co., Ltd. and Denacol (trade name) manufactured by Nagase Chemical Industries, Ltd.

[0107] <Preparation of Photosensitive Resin Composition> The method for preparing the photosensitive resin composition is not particularly limited, and may be a known method, for example, a method in which the above-mentioned components are mixed and dispersed using various mixers and dispersers. The mixing and dispersion step is not particularly limited, and may be performed by a known method. In addition, other steps that are usually performed may be further included.

[0108] 3.Cured product The present invention also includes a cured product obtained by curing the above-mentioned alkali-soluble resin or photosensitive resin composition. The cured product of the present invention has excellent low dielectric properties. The cured product of the present invention is also excellent in photocurability, heat resistance, and heat-resistant coloration.

[0109] The dielectric constant of the cured product is preferably 1 to 3.0, more preferably 1.5 to 2.9, and even more preferably 1.6 to 2.7, in view of small transmission loss. The dielectric constant can be determined by the method described in the examples below.

[0110] The 5% weight loss temperature of the cured product is preferably 300 to 500° C., more preferably 310 to 450° C., even more preferably 320 to 400° C., and even more preferably 350 to 400° C., in view of good thermal decomposition resistance. The 5% weight loss temperature can be determined by the method described in the examples below.

[0111] The method for obtaining the cured product using the alkali-soluble resin or photosensitive resin composition of the present invention is not particularly limited, and may be a known method. For example, the above-mentioned alkali-soluble resin or photosensitive resin composition is applied to a substrate or molded, and then heated, irradiated with active energy rays such as ultraviolet rays, or a combination of these, to cure the product. Among them, the method for producing the cured product preferably includes a step (1) of heating the alkali-soluble resin or the photosensitive resin composition at 50 to 200°C, a step (2) of irradiating the heated product obtained in the step (1) with active energy rays, and a step (3) of heating the irradiated product obtained in the step (2) at 80 to 400°C. The method for producing the cured product of the alkali-soluble resin does not have to include the step (2).

[0112] Process (1) Step (1) is a step (pre-baking step) of heating the alkali-soluble resin or the photosensitive resin composition at 50 to 200° C. This step removes insoluble components such as the solvent, making it easier for the subsequent curing reaction to proceed.

[0113] The alkali-soluble resin or the photosensitive resin composition in step (1) may be applied onto a substrate or may be molded. The substrate is not particularly limited and may be appropriately selected depending on the purpose and application. Examples of the substrate include substrates made of various materials such as a glass plate and a plastic plate. The coating method is not particularly limited, and may be a known method such as spin coating, slit coating, roll coating, or cast coating. The molding method is not particularly limited, and may be a known method such as extrusion molding or injection molding.

[0114] The heating in the above step (1) is not particularly limited, and may be performed by known heating means such as a hot plate, an IR oven, or a convection oven. The heating temperature in the above step (1) is preferably 60 to 180° C., more preferably 70 to 160° C., in terms of efficient removal of the solvent.

[0115] Process (2) Step (2) is a step of irradiating the heated product obtained in step (1) with active energy rays to photocure it. The method of irradiating the active energy rays is not particularly limited, and can be performed by a known method. Examples of the light source of the active light rays used for light irradiation include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, medium pressure mercury lamps, low pressure mercury lamps, carbon arcs, and fluorescent lamps, and laser light sources such as argon ion lasers, YAG lasers, excimer lasers, nitrogen lasers, helium cadmium lasers, and semiconductor lasers.

[0116] When the active energy rays are irradiated, the irradiation may be performed through a photomask. As the photomask, a mask having light-shielding portions formed according to a desired pattern is preferably used.

[0117] It is preferable to have a step of irradiating active energy rays through a photomask, and then developing the layer with a developer to remove the unirradiated portions. The irradiated portions are cured by the irradiation of active energy rays, and the cured product is made insoluble or poorly soluble in the developer. On the other hand, the unirradiated portions dissolve in the developer, and are removed by the development, thereby obtaining a patterned cured film. The development can be usually carried out at a development temperature of 10 to 50°C by a method such as immersion development, spray development, brush development, or ultrasonic development.

[0118] The developer is not particularly limited as long as it dissolves or peels off the alkali-soluble resin and the photosensitive resin composition, but usually, an organic solvent or an alkaline aqueous solution is used, and a mixture of these may 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 described in JP-A-2015-157909.

[0119] Process (3) After the above step (2), the irradiated product is heated at 80 to 400° C. Step (3) is a post-curing (post-baking) step for obtaining a cured product by curing with heat. The heating temperature in this case is preferably 100 to 380° C., more preferably 120 to 360° C., and even more preferably 140 to 340° C., in order to allow ring closure.

[0120] The heating time is not particularly limited and is, for example, 5 to 180 minutes, preferably 10 to 120 minutes, and more preferably 20 to 60 minutes. The heating method is also not particularly limited and can be performed using known heating equipment such as a hot plate, a convection oven, or a high-frequency heater.

[0121] When the cured product is a cured film, the film thickness is preferably 0.1 to 50 μm, more preferably 0.5 to 40 μm, and even more preferably 1 to 30 μm, in order to fully exhibit low dielectric properties.

[0122] The photosensitive resin composition of the present invention can be used, for example, in the form of a dry film, in addition to being directly applied to a substrate in liquid form. In this case, the photosensitive resin composition of the present invention is first applied to a film such as polyethylene terephthalate and dried to prepare a dry film. The obtained dry film is laminated on a substrate, and the film is peeled off before or after exposure to light, thereby obtaining a substrate on which a cured product of the photosensitive resin composition is laminated.

[0123] In addition, a CTP (Computer To Plate) system, which has recently been widely used in the field of printing plate making, can also be used. That is, after forming a coating film of the photosensitive resin composition of the present invention, a pattern forming film is not used during exposure, and a method can be adopted in which the coating film is directly scanned and exposed with laser light according to digitized data to form a pattern.

[0124] 4.Applications The alkali-soluble resin and photosensitive resin composition of the present invention have excellent developability and can provide a cured product with low dielectric properties. Therefore, the alkali-soluble resin and photosensitive resin composition of the present invention can be suitably used in applications requiring developability and low dielectric properties. In addition, the alkali-soluble resin and photosensitive resin composition of the present invention are also excellent in photocurability, heat resistance, and heat-resistant coloring. The alkali-soluble resin and photosensitive resin composition of the present invention are suitably used for optical materials and can be suitably used for resists. The alkali-soluble resin of the present invention is preferably a polymer for resists, more preferably a polymer for negative resists.

[0125] The alkali-soluble resin and photosensitive resin composition of the present invention can be suitably used for applications including, for example, color filters, black matrices, photospacers, black column spacers, inks, printing plates, printed wiring boards, semiconductor elements, photoresists, interlayer insulating films, rewiring layers, films, organic protective films, and other components of various optical members and electric and electronic devices. EXAMPLES

[0126] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0127] The various evaluation methods used in the present examples are as follows. <Weight average molecular weight> The weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC) measurement using polystyrene as a standard substance under the following measurement conditions: Apparatus: Gel permeation chromatography apparatus HLC-8320GPC (manufactured by Tosoh Corporation) Column: TSKgel SuperHZM-M (Tosoh Corporation) Detector: RI detector for liquid chromatography Measurement temperature: 40℃ Solvent: THF (tetrahydrofuran) Sample concentration: 0.05g / 10cc Sample flow rate: 0.6 ml / min

[0128] <Acid value> 3 g of the resin solution was precisely weighed out and dissolved in a mixed solvent of 90 g of acetone and 10 g of water, and titrated using a 0.1 N KOH aqueous solution as a 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 solid content (mgKOH / g) was calculated from the acid value of the resin solution and the solid content of the resin solution. The solid content of the resin solution was determined by the following method. That is, about 1 g of the resin solution was weighed out in an aluminum cup, about 3 g of acetone was added to dissolve it, and then it was naturally dried at room temperature. Then, it was dried at 160°C under vacuum for 1.5 hours using a hot air dryer (product name: PHH-101, manufactured by Espec Corporation), and then it was cooled in a desiccator and the mass was measured. The solid content (mass%) of the resin solution was calculated from the amount of mass loss.

[0129] <Double bond equivalent> It was determined by dividing the mass (g) of the resin by the amount (mol) of polymerizable double bonds in the resin.

[0130] <Dielectric constant, dielectric loss tangent> Acetone was added to 30 g of the resin solution to prepare 300 g of diluted resin solution, and the diluted resin solution was dropped into 3 kg of hexane while stirring to reprecipitate the resin, and then heated to 200°C to melt it, and a rod-shaped resin sample with a diameter of 1 to 2 mm was obtained using a melt indexer. The dielectric constant and dielectric loss tangent of the obtained resin sample were measured using a network analyzer E8361A (manufactured by Agilent Technologies) by the cavity resonator perturbation method under the conditions of temperature 25°C, humidity 50%, and frequency 10 GHz.

[0131] <5% weight loss temperature> A reprecipitate of the resin solution obtained by the same method as the above-mentioned dielectric constant measurement method was used as a sample. Using a TG-DTA2000SR (manufactured by NESZTCH) and an MTC1000SA (manufactured by Bruker), the sample was heated from room temperature to 500°C at 10°C per minute under nitrogen gas flow, and the temperature at which the weight loss reached 5% was measured, and this temperature was defined as the 5% weight loss temperature.

[0132] * Value> ​The resin solution was diluted with propylene glycol monomethyl ether acetate to a resin solid concentration of 20%, and applied to a 10 cm square glass substrate by spin coating. After heat treatment (90°C, 3 minutes), it was further heat treated at 250°C for 3 hours to form a coating film (thickness 2 μm). Then, the b of the coating film was measured using a spectrophotometer (manufactured by KONICA MINOLTA, product name CM-3700A). * The smaller the value, the less likely the sample was to be discolored and the better the heat discoloration resistance.

[0133] <Development time (sec)> A photosensitive resin composition was obtained by adding 10% dipentaerythritol hexaacrylate (DPHA) and 5% photopolymerization initiator (Irgacure907, manufactured by BASF) to the solid content of the resin solution, and mixing propylene glycol monomethyl ether acetate (PEGMEA) so that the resin solid content was 30%. The obtained photosensitive resin composition was applied to a 10 cm square glass substrate by spin coating, and after heat treatment (90°C, 3 minutes), it was irradiated with 60 mJ / cm using a UV aligner (manufactured by Dai Nippon Kaken Co., Ltd., product name "MA-1100") equipped with a 2.0 kW ultra-high pressure mercury lamp through a photomask with a 30 μm line and space opening at a distance of 50 μm from the coating film. 2 (converted into 365 nm illuminance), a 2.38% aqueous solution of tetramethylammonium hydroxide was sprayed using a spin developer to dissolve or peel off and remove the unexposed areas, and the remaining exposed areas were developed by washing with pure water for 10 seconds, thereby evaluating developability. Specifically, the coating film developed through the photomask as described above was observed with a surface roughness meter (manufactured by Ryoka Systems Co., Ltd., product name "VertScan2.0"), and the development time was determined as the spraying time of 2.38% tetramethylammonium hydroxide aqueous solution required for the unexposed areas to flow.

[0134] <Water resistance> The resin solution was diluted to 20% with propylene glycol monomethyl ether acetate, and applied to a 10 cm square glass substrate by spin coating, heat-treated (90°C, 3 minutes), and then heat-treated at 200°C for 2 hours. The substrate was then submerged in 20 g of water in a petri dish, and the film weight was measured before and after 24 hours of submersion. The rate of change was calculated using the following formula, with no change being STD=100. Rate of change = film weight after 24 hours of submersion / film weight before submersion × 100

[0135] Example 1 Synthesis of Resin (A-1) A reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube and a dropping vessel inlet was charged with 92.5 parts of propylene glycol monomethyl ether acetate, substituted with nitrogen, and heated to 90 ° C. On the other hand, a dropping vessel (A) was prepared by stirring and mixing 120 parts of propylene glycol monomethyl ether acetate, 40.0 parts of N-benzyl maleimide, 15.0 parts of maleic acid, and 2.0 parts of t-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation, "Perbutyl (registered trademark) O") in a beaker, and a dropping vessel (B) was prepared by stirring and mixing 0.5 parts of n-dodecyl mercaptan and 45.0 parts of vinyl toluene. After the temperature of the reaction vessel reached 90 ° C., while maintaining the same temperature, dropping was started from the dropping vessel over 4 hours, and polymerization was carried out. After the dropwise addition, the temperature was kept at 90°C for 30 minutes, and then 0.5 parts of t-butylperoxy-2-ethylhexanoate was added and the reaction was continued for another 30 minutes at 90°C. The temperature was then raised to 115°C and aged for 90 minutes. The mixture was cooled to room temperature to obtain a resin solution (A-1).

[0136] Example 2 Synthesis of resin (A-2) The same procedure as in Example 1 was carried out, except that vinyltoluene was replaced with styrene. Next, 12.2 parts of glycidyl methacrylate, 0.2 parts of Antage W-400 (Kawaguchi Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.3 parts of triethylamine as a catalyst were added, and the temperature was raised to 110°C while bubbling a nitrogen-air mixed gas adjusted to an oxygen concentration of 7%, and the reaction was carried out for 2 hours. After that, the temperature was raised to 115°C and the reaction was carried out for 5 hours to complete the reaction, and the reaction was cooled to room temperature to obtain a resin solution (A-2).

[0137] Example 3 Synthesis of resin (A-3) In a reaction vessel equipped with a thermometer, a stirrer, a gas inlet tube, a cooling tube and a dropping vessel inlet, 64.3 parts of propylene glycol monomethyl ether acetate and 64.3 parts of propylene glycol monomethyl ether were charged, and after nitrogen replacement, the temperature was raised to 90 ° C. by heating. On the other hand, as a dropping vessel (A), a beaker was prepared in which 42 parts of propylene glycol monomethyl ether acetate, 42 parts of propylene glycol monomethyl ether, 28.0 parts of N-benzyl maleimide, 40.0 parts of maleic acid, and 2.0 parts of t-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation, "Perbutyl (registered trademark) O") were stirred and mixed, and a dropping vessel (B) was prepared in which 0.5 parts of n-dodecyl mercaptan and 32.0 parts of vinyl toluene were stirred and mixed. After the temperature of the reaction vessel reached 90 ° C., while maintaining the same temperature, dropping was started from the dropping vessel over 4 hours, and polymerization was carried out. After the dropwise addition, the temperature was kept at 90°C for 30 minutes, and then 0.5 parts of t-butylperoxy-2-ethylhexanoate was added and the reaction was continued for another 30 minutes at 90°C. The temperature was then raised to 115°C and aged for 90 minutes. The mixture was cooled to room temperature to obtain a resin solution (A-3).

[0138] Example 4 Synthesis of resin (A-4) The same procedure was carried out as in Example 1, except that 40.0 parts of N-benzylmaleimide was changed to 20.0 parts, 15.0 parts of maleic acid was changed to 35.0 parts of monobutyl maleate, and 45.0 parts of vinyltoluene was changed to 45.0 parts of styrene, to obtain a resin solution (A-4).

[0139] Example 5 Synthesis of resin (A-5) In Example 2, the same operation was carried out except that 40.0 parts of N-benzylmaleimide was changed to 20.0 parts, styrene was changed to vinyltoluene, 15.0 parts of maleic acid was changed to 35.0 parts of monobutyl maleate, and 12.2 parts of glycidyl methacrylate was changed to 4.1 parts, to obtain a resin solution (A-5).

[0140] Example 6 Synthesis of resin (A-6) A resin solution (A-6) was obtained in the same manner as in Example 1, except that N-benzylmaleimide was replaced with maleic anhydride.

[0141] Example 7 Synthesis of resin (A-7) The same procedure was carried out as in Example 6, except that vinyltoluene was replaced with styrene. Then, 6.7 parts of 2-methacryloyloxyethyl isocyanate ("Karends MOI (registered trademark)" manufactured by Showa Denko), 0.2 parts of Antage W-400 (manufactured by Kawaguchi Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.3 parts of triethylamine as a catalyst were added, and the mixture was heated to 90°C while bubbling a nitrogen-air mixed gas adjusted to an oxygen concentration of 7%, and reacted for 8 hours. After that, it was cooled to room temperature to obtain a resin solution (A-7).

[0142] Example 8 Synthesis of resin (A-8) The same procedure as in Example 1 was carried out, except that 40.0 parts of N-benzylmaleimide was changed to 0 parts, and 45.0 parts of vinyl toluene was changed to 85.0 parts, to obtain a resin solution (A-8).

[0143] Example 9 Synthesis of resin (A-9) A resin solution (A-9) was obtained in the same manner as in Example 1, except that 40.0 parts of N-benzylmaleimide was replaced with 40.0 parts of 2-norbornene.

[0144] Comparative Example 1 Synthesis of resin (B-1) A resin solution (B-1) was obtained in the same manner as in Example 1, except that maleic acid was changed to acrylic acid.

[0145] Comparative Example 2 Synthesis of resin (B-2) A resin solution (B-2) was obtained in the same manner as in Example 1, except that vinyl toluene was replaced with benzyl methacrylate.

[0146] Comparative Example 3 Synthesis of resin (B-3) The same procedure as in Example 1 was carried out except that maleic acid was changed to maleic anhydride, to obtain a resin solution (B-3).

[0147] Comparative Example 4 Synthesis of resin (B-4) The same procedure as in Example 1 was carried out, except that 40.0 parts of N-benzylmaleimide was changed to 0 parts, and 45.0 parts of vinyltoluene was changed to 85.0 parts of benzyl methacrylate, to obtain a resin solution (B-4).

[0148] The resins obtained in the above Examples and Comparative Examples were evaluated by the above methods. The results are shown in Table 1. The descriptions in the table are as follows: BzMI: N-benzylmaleimide BzMA: benzyl methacrylate VT: Vinyl toluene ST: styrene AA: Acrylic acid GMA: glycidyl methacrylate Karenz MOI: 2-Methacryloyloxyethyl isocyanate

[0149] [Table 1]

[0150] From Table 1, it was found that the resins (A-1) to (A-9) of the examples were excellent in developability and low dielectric properties. It was also found that the resins (A-1) to (A-9) of the examples were excellent in heat resistance.

Claims

1. An alkali-soluble resin having a structural unit (A) represented by the following general formula (1) and a structural unit (B) derived from an aromatic vinyl monomer, and having an acid value of 20 mgKOH / g or more: 【Chemistry 1】 (In the formula, R １ , R ２ and R ３ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or -R ５ -COOR ６ R represents a group represented by １ ~R ３ Any one of the following is -R ５ -COOR ６ R is a group represented by the formula: ４ represents a direct bond or an alkylene group having 1 to 3 carbon atoms. ５ represents a direct bond or an alkylene group having 1 to 3 carbon atoms. ６ represents a hydrogen atom or an organic group having 1 to 20 carbon atoms (excluding polymerizable unsaturated groups).

2. 2. The alkali-soluble resin according to claim 1, further comprising a structural unit (C) having a main chain ring structure.

3. The alkali-soluble resin according to claim 2, characterized in that the structural unit (C) having a main chain ring structure is at least one selected from the group consisting of a structural unit derived from an N-substituted maleimide, a structural unit derived from a dialkyl-2,2'-(oxydimethylene)diacrylate monomer, and a structural unit derived from an unsaturated dicarboxylic acid anhydride.

4. The content of the structural unit (A) is 5 to 70% by mass, based on 100% by mass of all structural units of the alkali-soluble resin; 2. The alkali-soluble resin according to claim 1, wherein the content of the structural unit (B) is 3 to 90% by mass relative to 100% by mass of all structural units of the alkali-soluble resin.

5. 3. The alkali-soluble resin according to claim 2, wherein the content of the structural unit (C) is 1 to 60% by mass relative to 100% by mass of all structural units of the alkali-soluble resin.

6. 2. The alkali-soluble resin according to claim 1, which has a weight average molecular weight of 4,000 to 100,000.

7. 2. The alkali-soluble resin according to claim 1, which has a polymerizable double bond in a side chain.

8. 2. The alkali-soluble resin according to claim 1, wherein the structural unit (A) is a structural unit derived from maleic acid.

9. 2. The alkali-soluble resin according to claim 1, which is a polymer for a negative resist.

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

11. A cured product obtained by curing the alkali-soluble resin according to claim 1 or the photosensitive resin composition according to claim 10.

12. A method for producing an alkali-soluble resin, comprising the steps of: The method includes a step of polymerizing a monomer component including a monomer (a) represented by the following general formula (2) and an aromatic vinyl monomer (b):

1. A method for producing an alkali-soluble resin, comprising the steps of: 【Chemistry 2】 (In the formula, R １ , R ２ and R ３ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or -R ５ -COOR ６ R represents a group represented by １ ~R ３ Any one of the following is -R ５ -COOR ６ R is a group represented by the formula: ４ represents a direct bond or an alkylene group having 1 to 3 carbon atoms. ５ represents a direct bond or an alkylene group having 1 to 3 carbon atoms. ６ represents a hydrogen atom or an organic group having 1 to 20 carbon atoms (excluding polymerizable unsaturated groups).

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