Composition for forming protective layer, protective layer, and method for producing protective layer

Abstract

To provide a composition for forming a protective layer that exhibits superior curability, thick-film curability, curing shrinkage property, and adhesiveness even when having low viscosity.SOLUTION: A composition for forming a protective layer comprises a monofunctional (meth)acrylate (A), a polyfunctional (meth)acrylate (B), and a photopolymerization initiator (C), wherein the photopolymerization initiator (C) contains one or more compounds selected from the group consisting of the general formulas (1), (2), (3), and (4), the amount of the polyfunctional (meth)acrylate being 0.5 to 30 pts.wt. relative to 100 pts.wt. of the monofunctional (meth)acrylate, and the viscosity of the composition for forming a protective layer being 100 mPa s or less at 25°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a protective layer, a protective layer, and a method for producing a protective layer. [Background technology]

[0002] Semiconductors are used in a variety of electronic devices, and recent advances in the performance of electronic devices have led to advances in integration and density. Traditionally, higher integration and higher speed in semiconductors have been achieved by miniaturizing pattern dimensions through shorter wavelength light sources in lithography technology using optical exposure (photolithography). However, miniaturization of pattern dimensions is approaching an essential limit imposed by the wavelength of the light source used in photolithography.

[0003] In recent years, three-dimensional semiconductor packaging has become essential to achieve even higher integration and density. To achieve this, the substrate and the semiconductor manufacturing equipment that comes into contact with the substrate must be made thinner and precisely flat, which is achieved by polishing the substrate and semiconductor manufacturing equipment.

[0004] To prevent quality defects due to damage to the substrate caused by impact during polishing, contamination of the surface by residue after polishing, etc., a method of forming a protective layer obtained by curing a photocurable resin composition on the surface of the substrate or semiconductor manufacturing equipment is generally known. For example, Patent Document 1 discloses a method of using a photocurable acrylic resin composition as the protective layer, and Patent Document 2 discloses a method of using a photocurable acrylic / epoxy resin composition as the protective layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-272557 [Patent Document 2] Patent Publication No. 2021-116353 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, substrates and semiconductor manufacturing equipment have sometimes had fine protrusions or patterns on their surfaces, and when a photocurable resin composition is used as a protective layer, there is a possibility that the substrate may be warped or the protrusions or patterns may be damaged due to curing shrinkage during photocuring as the substrate, etc., becomes thinner. Furthermore, from the viewpoint of shock absorption during polishing, adhesion is required in addition to suppression of curing shrinkage, but when the substrate, etc., has a surface with a deep pattern, there has been a problem that poor adhesion is likely to occur.

[0007] Generally, acrylic resin compositions exhibit high cure shrinkage upon photocuring, and epoxy resins are often used to suppress this. However, to ensure adhesion, the composition must be made low in viscosity. This is often achieved by using a reactive diluent, which reduces curability. Furthermore, epoxy resins have a slower photocuring rate than acrylic resins, and the formation of a protective film requires time, posing a challenge from an economic standpoint.

[0008] The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a composition for forming a protective layer that has excellent curability, thick-film curability, cure shrinkage, and adhesion even at a low viscosity. [Means for solving the problem]

[0009] That is, the present invention provides a composition for forming a protective layer, which contains a monofunctional (meth)acrylate (A), a polyfunctional (meth)acrylate (B), and a photopolymerization initiator (C), The photopolymerization initiator (C) contains one or more compounds selected from the group consisting of the following general formulas (1), (2), (3), and (4): The protective layer-forming composition includes 0.5 parts by weight or more and 30 parts by weight or less of the polyfunctional (meth)acrylate relative to 100 parts by weight of the monofunctional (meth)acrylate, and the viscosity of the protective layer-forming composition at 25°C is 100 mPa·s or less. General formula (1): [ka] (In general formula (1), R 1 , R 2 , R 3 and R 4 independently represent a methyl group or an ethyl group, and R 5 represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, and R 6 are independent substituents each representing an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a chlorine atom, and n represents an integer of 0 to 2. General formula (2): [ka] (In general formula (2), R 7 and R 8 R independently represents a methyl group or an ethyl group. 9 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. X represents a group represented by the following general formula (2-a): Ar 1 , Ar 2 , Ar 3 or Ar 4 n is an integer of 0 to 2. A triazine derivative having a peroxide bond represented by the formula: [ka] (In the general formula (2-a), m represents an integer of 0 to 3. R 10 are independent substituents, and are alkyl groups having 1 to 18 carbon atoms, and are represented by the general formula (2-b): R 11 represents a substituent represented by -Y-, a nitro group, or a cyano group. The Y represents an oxygen atom or a sulfur atom. The R 11 represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a terminal hydroxyl group in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. 10 is two adjacent groups of the general formula (2-b): R 11-Y- may form a 5- or 6-membered ring.) General formula (3): [ka] (In general formula (3), R 12 and R 13 are independently a methyl group or an ethyl group, R 14 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, and R 15 represents an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms, an optionally substituted acyl group having 1 to 20 carbon atoms, -YR, or -N-RR', where Y represents an oxygen atom or a sulfur atom, and R and R' independently represent a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, or an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms. Ar represents a group represented by the following general formula (3-a): Ar 5 , Ar 6 , Ar 7 or Ar 8 The triazine derivative having a peroxide bond represented by the formula (I) is an aryl group represented by the formula (I). [ka] (In general formula (3-a), m represents an integer of 0 to 3. R 16 are independent substituents, and are alkyl groups having 1 to 18 carbon atoms, and are represented by the general formula (3-b): R 17 represents a substituent represented by -Y-, a nitro group, or a cyano group. The Y represents an oxygen atom or a sulfur atom. The R 17 represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a terminal hydroxyl group in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. 16 is two adjacent groups of the general formula (3-b): R 17-Y- may form a 5- or 6-membered ring.) A compound represented by general formula (4): [ka]

[0010] The present invention also relates to the composition for forming a protective layer, which preferably further contains a leveling agent (D).

[0011] The present invention also relates to a protective layer formed from the composition for forming a protective layer.

[0012] The present invention also relates to a method for producing a protective layer, comprising the steps of applying the protective layer-forming composition to a substrate to form a composition layer, and irradiating the composition layer with active energy rays to cure the composition layer. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a composition for forming a protective layer that has excellent curability, thick film curability, cure shrinkage, and adhesion even at a low viscosity. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Protective layer forming composition> The composition for forming a protective layer of the present invention contains a monofunctional (meth)acrylate (A), a polyfunctional (meth)acrylate (B), and a photopolymerization initiator (C), wherein the photopolymerization initiator (C) contains one or more compounds selected from the group consisting of the following general formulas (1), (2), (3), and (4), and the polyfunctional (meth)acrylate is present in an amount of 1 part by weight or more and 30 parts by weight or less per 100 parts by weight of the monofunctional (meth)acrylate, and the viscosity of the composition for forming a protective layer at 25°C is 100 mPa s or less.

[0015] <Monofunctional (meth)acrylate (A)> The monofunctional (meth)acrylate (A) of the present invention is not particularly limited, and conventionally known monofunctional (meth)acrylates can be used. For example, alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate; cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 2- Ester compounds of (meth)acrylic acid and alicyclic alcohols, such as ethyl-2-adamantyl (meth)acrylate; aryl (meth)acrylates, such as phenyl (meth)acrylate and benzyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-hydroxy-1-adamantyl (meth)acrylate, hydroxyl-terminated polyethylene glycol mono(meth)acrylate, hydroxyl-terminated polypropylene Monomers having a hydroxy group such as polyethylene glycol mono(meth)acrylate; methoxyethyl(meth)acrylate, methoxypolyethylene glycol(meth)acrylate, phenoxypolyethylene glycol(meth)acrylate, 2-phenylphenoxyethyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl(meth)acrylate, (3-ethyloxetan-3-yl)methyl(meth)acrylate, cyclic trimethylol Monomers having a chain or cyclic ether bond, such as diolpropane formal (meth)acrylate; monomers having a nitrogen atom, such as N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-isopropyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, diacetone (meth)acrylamide, (meth)acryloylmorpholine, and N-(meth)acryloyloxyethyl hexahydrophthalimide;Monomers having an isocyanate group such as 2-(meth)acryloyloxyethyl isocyanate; monomers having an epoxy group such as glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether; monomers having a phosphorus atom such as 2-((meth)acryloyloxy)ethyl phosphate; monomers having a silicon atom such as 3-(meth)acryloxypropyltrimethoxysilane; monomers having a fluorine atom such as 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate and 2-(perfluorohexyl)ethyl (meth)acrylate; and monomers having a carboxyl group such as (meth)acrylic acid, mono(2-(meth)acryloyloxyethyl) succinate, mono(2-(meth)acryloyloxyethyl) phthalate, mono(2-(meth)acryloyloxyethyl) maleate and ω-carboxy-polycaprolactone mono(meth)acrylate. Among the above, alicyclic structure-containing (meth)acrylates are preferred, and isobornyl (meth)acrylate is more preferred, because they have a bulky structure and undergo little shrinkage upon curing. The monofunctional (meth)acrylate (A) may be used alone or in any combination and ratio of two or more.

[0016] The proportion of the monofunctional (meth)acrylate (A) in the protective layer-forming composition is preferably 55% by weight or more and 95% by weight or less, and more preferably 70% by weight or more and 95% by weight or less. By making the content of the monofunctional (meth)acrylate (A) equal to or more than the lower limit, the protective layer-forming composition can exhibit good curability while having a low viscosity.

[0017] <Polyfunctional (meth)acrylate (B)> The polyfunctional (meth)acrylate (B) of the present invention is a compound having two or more radically polymerizable functional groups, such as ethylenically unsaturated groups, in the molecule. The polyfunctional (meth)acrylate (A) is not particularly limited, and a conventionally known one can be used, for example, dipropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol dimethacrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, EO (ethylene oxide) adduct di(meth)acrylate of bisphenol A, bisphenol A di(meth)acrylate ... Examples of the propylene oxide (PO) adduct di(meth)acrylate of Nol A, polytetramethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin propoxy tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol ethoxy tetra(meth)acrylate, caprolactam-modified dipentaerythritol hexa(meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and the like. Among these, urethane (meth)acrylates are preferably used because they are easy to synthesize, readily available, and have good curability and adhesion. The polyfunctional (meth)acrylate (B) may be used alone or in any combination and ratio of two or more.

[0018] The number of functional groups in the polyfunctional (meth)acrylate (B) is preferably 3 to 9, more preferably 4 to 6. When the functionality is 3 or more, good curability is exhibited, and when the functionality is 9 or less, cure shrinkage can be suppressed.

[0019] The amount of the polyfunctional (meth)acrylate is 0.5 parts by weight or more and 30 parts by weight or less relative to 100 parts by weight of the monofunctional (meth)acrylate. From the viewpoint of curability, the amount of the polyfunctional (meth)acrylate is preferably 1 part by weight or more relative to 100 parts by weight of the monofunctional (meth)acrylate, and from the viewpoint of cure shrinkage, the amount of the polyfunctional (meth)acrylate is preferably 25 parts by weight or less relative to 100 parts by weight of the monofunctional (meth)acrylate.

[0020] From the viewpoint of the physical properties and curing speed of the cured product, the total proportion of the monofunctional (meth)acrylate (A) and the polyfunctional (meth)acrylate (B) in the composition for forming a protective layer is preferably 80% by weight or more, more preferably 85% by weight or more, and even more preferably 90% by weight or more.

[0021] <Photopolymerization initiator (C)> The photopolymerization initiator (C) of the present invention is one or more compounds selected from the group consisting of the following general formulae (1), (2), (3), and (4). General formula (1): [ka] (In general formula (1), R 1 , R 2 , R 3 and R 4 independently represent a methyl group or an ethyl group, and R 5 represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, and R 6 are independent substituents each representing an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a chlorine atom, and n represents an integer of 0 to 2.

[0022] In general formula (1), R 1 , R2 , R 3 and R 4 In the present invention, from the viewpoint of improving the stability of the thioxanthone derivative having a peroxide bond represented by general formula (1), R 1 , R 2 , R 3 and R 4 are preferably all methyl groups.

[0023] In general formula (1), R 5 is an alkyl group having 1 to 6 carbon atoms or a phenyl group. The alkyl group may be a straight chain or a branched chain. 5 Specific examples of R include a methyl group, an ethyl group, a propyl group, a 2,2-dimethylpropyl group, and a phenyl group. Among these, from the viewpoint of ease of synthesis of a thioxanthone derivative having a peroxide bond, R 5 is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably one selected from a methyl group, an ethyl group, and a propyl group. 5 is more preferably a methyl group or an ethyl group.

[0024] In general formula (1), the substitution position of the dialkyl peroxide on the thioxanthone is not particularly limited. From the viewpoint of efficiently converting light energy into thermal energy, the substitution is preferably at the 2nd, 3rd, or 4th position of the thioxanthone skeleton, and from the viewpoint of ease of synthesis, the substitution is more preferably at the 2nd or 3rd position of the thioxanthone skeleton.

[0025] In general formula (1), R 6 are independent substituents and represent an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a chlorine atom. These substituents improve the light absorption properties of the thioxanthone derivative having a peroxide bond due to the push-pull effect of these substituents at the emission wavelength of the light source used, allowing for efficient light absorption.

[0026] In the general formula (1), n ​​represents an integer of 0 to 2. Among these, n is preferably an integer of 0 to 1, and more preferably 0, from the viewpoint of easily synthesizing a thioxanthone derivative having a peroxide bond.

[0027] In general formula (1), when n is an integer of 1 to 2, R 6 The substitution position of is not particularly limited, but from the viewpoint of efficient light absorption, it is preferably the 6th or 7th position of the thioxanthone skeleton, and from the viewpoint of easy synthesis of a thioxanthone derivative having a peroxide bond, it is more preferably the 7th position of the thioxanthone skeleton.

[0028] R 6 Specific examples of R include alkyl groups such as methyl, ethyl, isopropyl, and n-butyl; alkoxy groups such as methoxy, ethoxy, n-propyloxy, sec-butyloxy, and tert-butyloxy; and chlorine atoms. Among these, from the viewpoint of efficient light absorption, R 6 is more preferably a methoxy group or an ethoxy group.

[0029] General formula (2): [ka] (In general formula (2), R 7 and R 8 R independently represents a methyl group or an ethyl group. 9 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. X represents a group represented by the following general formula (2-a): Ar 1 , Ar 2 , Ar 3 or Ar 4 n is an integer of 0 to 2. A triazine derivative having a peroxide bond represented by the formula: [ka] (In the general formula (2-a), m represents an integer of 0 to 3. R 10are independent substituents, and are alkyl groups having 1 to 18 carbon atoms, and are represented by the general formula (2-b): R 11 represents a substituent represented by -Y-, a nitro group, or a cyano group. The Y represents an oxygen atom or a sulfur atom. The R 11 represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a terminal hydroxyl group in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. 10 is two adjacent groups of the general formula (2-b): R 11 -Y- may form a 5- or 6-membered ring.)

[0030] In general formula (2), R 7 and R 8 R independently represents a methyl group or an ethyl group. 7 and R 8 is preferably a methyl group, from the viewpoint of increasing the stability of the triazine derivative having a peroxide bond.

[0031] In general formula (2), R 9 R is an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. The alkyl group may be either a straight chain or a branched chain. 9 Specific examples of the group include a methyl group, an ethyl group, a propyl group, a 2,2-dimethylpropyl group, a phenyl group, and an isopropylphenyl group. Among these, from the viewpoint of facilitating synthesis of a triazine derivative having a peroxide bond, a methyl group, an ethyl group, a propyl group, a 2,2-dimethylpropyl group, and a phenyl group are preferred. From the viewpoint of efficient light absorption, a methyl group and an ethyl group are more preferred.

[0032] In the general formula (2), n represents an integer of 0 to 2. From the viewpoint of easiness in synthesis of a triazine derivative having a peroxide bond, n is preferably 0 or 1. When n is 0, X is preferably Ar 2 , Ar 3 , or Ar 4and when n is 1, X is Ar 1 From the viewpoint of efficient light absorption, it is more preferable that the above-mentioned range is 0.1 to 1.0.

[0033] In the general formula (2-a), m represents an integer of 0 to 3. From the viewpoint of easiness in synthesis of a triazine derivative having a peroxide bond, m is preferably 0 to 2, and from the viewpoint of efficient light absorption, m is more preferably 1.

[0034] In general formula (2-a), R 10 are independent substituents, and are alkyl groups having 1 to 18 carbon atoms, and are represented by the general formula (2-b): R 11 represents a substituent represented by -Y-, a nitro group, or a cyano group. Y represents an oxygen atom or a sulfur atom. R 11 represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a terminal hydroxyl group in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. 10 is two adjacent general formula (2-b): R 11 -Y- may form a 5- or 6-membered ring.

[0035] R 10 is an independent substituent, from the viewpoint of efficient light absorption, and is an alkyl group having 1 to 6 carbon atoms, or a group represented by the general formula (2-c): R 11´ represents a substituent represented by -Y-, where Y represents an oxygen atom, and R 11´ is preferably a hydrocarbon group having 1 to 6 carbon atoms which may have one or more of an ether bond and a hydroxyl group at a terminal in the carbon skeleton, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. 10 is two adjacent general formula (2-c)R 11´ It is preferred that —Y— forms a 5- or 6-membered ring.

[0036] R 10Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, and n-hexyl; methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, sec-butyloxy, tert-butyloxy, n-pentyloxy, cyclopentyloxy, n-hexyloxy, cyclohexyloxy, 2-hydroxyethoxy, 2-methoxyethoxy, 2-ethoxyethoxy, 2-butoxyethoxy, 2-(2-hydroxyethoxy)ethoxy, 2-(2-ethoxyethoxy)ethoxy, 1,2-dihydroxypropoxy, and methylenedioxy. Examples of such functional groups include alkoxy groups such as oxy, dimethylmethylenedioxy, and ethylenedioxy; aryloxy groups such as phenyloxy and 4-isopropylphenyloxy; alkylsulfanyl groups such as methylsulfanyl, ethylsulfanyl, hexylsulfanyl, 2-methoxyethylsulfanyl, and 2-(2-methoxyethoxy)ethylsulfanyl; arylsulfanyl groups such as phenylsulfanyl, 2-methylphenylsulfanyl, and 4-methylphenylsulfanyl; and acyl groups such as acetyl, n-butanoyl, 2-ethylhexanoyl, benzoyl, and 2-methylbenzoyl. Compounds having these functional groups and represented by general formula (2) are preferred because they efficiently absorb light.

[0037] Furthermore, among these, triazine derivatives having a peroxide bond are easy to synthesize and, from the viewpoint of efficient light absorption, R 10 is more preferably a methoxy group, an ethoxy group, or a 2-hydroxyethoxy group.

[0038] R 10 The substitution position of X is not particularly limited, but 1 In the case of R 10 Preferably, at least one of the following is substituted at the 4-position of the benzene ring substituted with the triazine group. 2 In the case of R 10 Preferably, at least one of the following is substituted at the 4-position of a benzene ring other than the benzene ring substituted with the triazine group.3 In the case of R 10 Preferably, at least one of the following is substituted at the 4-position of the triazine group substituted at the 1-position. 4 In the case of R 10 In terms of efficient light absorption, it is preferable that at least one of the above is substituted at the 4-position of a benzene ring other than the benzene ring substituted with the triazine group.

[0039] General formula (3): [ka] (In general formula (3), R 12 and R 13 are independently a methyl group or an ethyl group, R 14 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, and R 15 represents an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms, an optionally substituted acyl group having 1 to 20 carbon atoms, -YR, or -N-RR', where Y represents an oxygen atom or a sulfur atom, and R and R' independently represent a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, or an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms. Ar represents a group represented by the following general formula (3-a): Ar 5 , Ar 6 , Ar 7 or Ar 8 The triazine derivative having a peroxide bond represented by the formula (I) is an aryl group represented by the formula (I). [ka] (In general formula (3-a), m represents an integer of 0 to 3. R 16 are independent substituents, and are alkyl groups having 1 to 18 carbon atoms, and are represented by the general formula (3-b): R 17 represents a substituent represented by -Y-, a nitro group, or a cyano group. The Y represents an oxygen atom or a sulfur atom. The R 17represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a terminal hydroxyl group in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. 16 is two adjacent groups of the general formula (3-b): R 17 -Y- may form a 5- or 6-membered ring.)

[0040] In general formula (3), R 12 and R 13 are independently a methyl group or an ethyl group, and a methyl group is preferred from the viewpoint of increasing the stability of the triazine derivative having a peroxide bond.

[0041] In general formula (3), R 14 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. The alkyl group may be either a straight chain or a branched chain. R 14 Specific examples of the group include a methyl group, an ethyl group, a propyl group, a 2,2-dimethylpropyl group, a phenyl group, and an isopropylphenyl group. Among these, from the viewpoint of facilitating synthesis of a triazine derivative having a peroxide bond, a methyl group, an ethyl group, a propyl group, a 2,2-dimethylpropyl group, and a phenyl group are preferred. From the viewpoint of increasing the stability of a triazine derivative having a peroxide bond and efficiently absorbing light, a methyl group and an ethyl group are more preferred.

[0042] In general formula (3), R 15represents an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms, an optionally substituted acyl group having 1 to 20 carbon atoms, -YR, or -N-RR', where Y represents an oxygen atom or a sulfur atom, and R and R' independently represent a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, or an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms. The "substituent" in the above "optionally substituted" includes a halogen atom, an aliphatic hydrocarbon group which may have an ether bond or a thioether bond in the carbon skeleton, an aromatic hydrocarbon group, a heterocyclic ring-containing group, an acyl group, a cyano group, a nitro group, a carboxyl group, an epoxy group, a hydroxyl group, and the like. The above R 15 is preferably an optionally substituted aliphatic hydrocarbon group of 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group of 6 to 20 carbon atoms, an optionally substituted heterocyclic ring-containing group of 2 to 20 carbon atoms, an optionally substituted acyl group of 1 to 20 carbon atoms, or -YR, from the viewpoint of high stability, and is more preferably -OR, in which R is an optionally substituted aliphatic hydrocarbon group of 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group of 6 to 20 carbon atoms, or an optionally substituted heterocyclic ring-containing group of 2 to 20 carbon atoms, from the viewpoint of ease of synthesis.

[0043] In general formula (3-a), m represents an integer of 0 to 3. From the viewpoint of easiness in synthesis of a triazine derivative having a peroxide bond, m is preferably 0 to 2, and from the viewpoint of efficient light absorption, m is more preferably 1.

[0044] In general formula (3-a), R 16 are independent substituents, and are alkyl groups having 1 to 18 carbon atoms, and are represented by the general formula (3-b): R 17 R represents a substituent represented by -Y-, a nitro group, or a cyano group. Y represents an oxygen atom or a sulfur atom. 17represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a terminal hydroxyl group in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. 16 is two adjacent general formula (2-b): R 17 -Y- may form a 5- or 6-membered ring.

[0045] R 16 is an independent substituent, from the viewpoint of efficient light absorption, and is an alkyl group having 1 to 6 carbon atoms, or a group represented by the general formula (2-c): R 17´ represents a substituent represented by -Y-, where Y represents an oxygen atom, and R 17´ is preferably a hydrocarbon group having 1 to 6 carbon atoms which may have one or more of an ether bond and a hydroxyl group at a terminal in the carbon skeleton, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. 16 is two adjacent general formula (2-c)R 17´ It is preferred that —Y— forms a 5- or 6-membered ring.

[0046] R 16Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, and n-hexyl; methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, sec-butyloxy, tert-butyloxy, n-pentyloxy, cyclopentyloxy, n-hexyloxy, cyclohexyloxy, 2-hydroxyethoxy, 2-methoxyethoxy, 2-ethoxyethoxy, 2-butoxyethoxy, 2-(2-hydroxyethoxy)ethoxy, 2-(2-ethoxyethoxy)ethoxy, 1,2-dihydroxypropoxy, and methylenedioxy. Examples of such functional groups include alkoxy groups such as oxy, dimethylmethylenedioxy, and ethylenedioxy; aryloxy groups such as phenyloxy and 4-isopropylphenyloxy; alkylsulfanyl groups such as methylsulfanyl, ethylsulfanyl, hexylsulfanyl, 2-methoxyethylsulfanyl, and 2-(2-methoxyethoxy)ethylsulfanyl; arylsulfanyl groups such as phenylsulfanyl, 2-methylphenylsulfanyl, and 4-methylphenylsulfanyl; and acyl groups such as acetyl, n-butanoyl, 2-ethylhexanoyl, benzoyl, and 2-methylbenzoyl. Compounds having these functional groups and represented by general formula (3) are preferred because they efficiently absorb light.

[0047] Furthermore, among these, triazine derivatives having a peroxide bond are easy to synthesize and, from the viewpoint of efficient light absorption, R 16 is more preferably a methoxy group, an ethoxy group, or a 2-hydroxyethoxy group.

[0048] R 16 The substitution position of X is not particularly limited, but 1 In the case of R 16 Preferably, at least one of the following is substituted at the 4-position of the benzene ring substituted with the triazine group. 2 In the case of R 16 Preferably, at least one of the following is substituted at the 4-position of a benzene ring other than the benzene ring substituted with the triazine group.3 In the case of R 16 is preferably substituted at the 4-position of the triazine group substituted at the 1-position. 4 In the case of R 16 In terms of efficient light absorption, it is preferable that at least one of the above is substituted at the 4-position of a benzene ring other than the benzene ring substituted with the triazine group.

[0049] A compound represented by general formula (4): [ka]

[0050] The compounds represented by the general formulas (1) to (4) may be used alone or in combination of two or more kinds.

[0051] In the present invention, the surface curability, deep curability, etc. of the composition for forming a protective layer can be improved by using other polymerization initiators in addition to the compounds represented by the above general formulas (1) to (4). When selecting other polymerization initiators, the types of monofunctional (meth)acrylate (A), polyfunctional (meth)acrylate (B), leveling agent (D), and other additives, the film thickness of the protective layer, etc. are taken into consideration.

[0052] Other polymerization initiators that can be used include known ones. For example, α-hydroxyacetophenone derivatives such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-propiophenone, 4'-(2-hydroxyethoxy)-2-hydroxy-2-methylpropiophenone, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one; 2-methyl-4'-methylthio-2-morpholinopropiophenone, 2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholino)-2-methylpropionyl; α-Aminoacetophenone derivatives such as 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one; acylphosphine oxide derivatives such as diphenyl-2,4,6-trimethylbenzoylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethyl (mesitylcarbonyl)phenylphosphinate; 1-[4-(phenylthio)phenyl]octane-1,2-dione-2-(O-benzoyloxy)phenyl oxime ester derivatives such as 1-[({1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethylidene}amino)oxy]ethanone; halomethyltriazine derivatives such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(3,4-dimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and 2-(4-ethoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine; 2,2-dimethyl benzyl ketal derivatives such as thioxanthone-2-phenylacetophenone; thioxanthone derivatives such as isopropylthioxanthone, benzophenone derivatives such as 4-(4-methylphenylthio)benzophenone; coumarin derivatives such as 3-benzoyl-7-diethylaminocoumarin and 3,3'-carbonylbis(7-diethylaminocoumarin); imidazole derivatives such as 2-(2-chlorophenyl)-1-[2-(2-chlorophenyl)-4,5-diphenyl-1,3-diazol-2-yl]-4,5-diphenylimidazole;Examples of the other polymerization initiators include organic peroxides such as 3,3',4,4'-tetrakis(tert-butylperoxycarbonyl)benzophenone and dibenzoyl peroxide; azo compounds such as azobisisobutyronitrile; and camphorquinone. The other polymerization initiators may be used alone or in combination of two or more.

[0053] The content of the photopolymerization initiator (C) is preferably 0.01 to 40 parts by weight, more preferably 0.05 to 20 parts by weight, and even more preferably 0.1 to 10 parts by weight, relative to 100 parts by weight of the monofunctional (meth)acrylate (A). When the content of the photopolymerization initiator (C) is 0.01 part by weight or more relative to 100 parts by weight of the monofunctional (meth)acrylate (A), the curability of the protective layer-forming composition can be improved. Furthermore, when the content of the photopolymerization initiator (C) is 40 parts by weight or less relative to 100 parts by weight of the monofunctional (meth)acrylate (A), the photopolymerization initiator (C) is sufficiently soluble in the monofunctional (meth)acrylate (A), and problems such as roughness of the film surface during film formation of the protective layer-forming composition and light absorption by the photopolymerization initiator itself that prevents light from reaching deep into the protective layer are less likely to occur.

[0054] <Leveling agent (D)> The protective layer-forming composition of the present invention may contain a leveling agent (D). This is blended for the purpose of improving leveling properties during coating. The type of leveling agent is not particularly limited, and known leveling agents can be used, such as fluorine-based leveling agents, silicone-based leveling agents, and acrylic leveling agents. These leveling agents can be used alone or in combination of two or more.

[0055] The proportion of the leveling agent (D) in the protective layer-forming composition is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, per 100 parts by weight of the monofunctional (meth)acrylate (A). When the amount of the leveling agent (D) is 0.001 part by weight or more, the wettability of the protective layer-forming composition can be improved. When the amount of the leveling agent (D) is 5 parts by weight or less, the amount of low-molecular-weight components in the protective layer-forming composition is not excessively high, which reduces the risk of damage to the device.

[0056] <Solvent> A solvent may be further added to the composition for forming a protective layer to improve viscosity, coating properties, and smoothness of the cured film, and is used to ensure the handleability and workability of the composition for forming a protective layer when molding, and there is no particular restriction on the amount used.

[0057] Examples of the solvent include acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, and ethanol. The solvents may be used alone or in combination of two or more.

[0058] <Other additives, etc.> The protective layer-forming composition may contain, as appropriate, known additives such as sensitizers, crosslinking agents, crosslinking accelerators, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), antioxidants, fillers, colorants (pigments, dyes, etc.), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, thickeners, flame retardants, inorganic compounds, and electromagnetic wave absorbing fillers, either alone or in combination of two or more, within the range that does not impair the properties of this embodiment.

[0059] <Method for preparing composition for forming protective layer> When preparing the composition for forming the protective layer, the monofunctional (meth)acrylate (A), the polyfunctional (meth)acrylate (B), the photopolymerization initiator (C), and, if necessary, the leveling agent (D) and other additives are placed in a container, and then dissolved or dispersed according to a conventional method using a paint shaker, a bead mill, a sand grind mill, a ball mill, an attritor mill, a two-roll mill, a three-roll mill, or the like.

[0060] The viscosity of the protective layer-forming composition measured at 25°C and 100 rpm using an E-type viscometer is 100 mPa s or less, preferably 70 mPa s or less, and more preferably 50 mPa s or less. When the viscosity is within this range, the protective layer-forming composition tends to have good wettability and adhesion to the substrate.

[0061] <Protective layer> The protective layer of the present invention is formed from the protective layer-forming composition. The thickness of the protective layer is not limited in any way, but can be, for example, 1 mm or less. Furthermore, from the viewpoint of utilizing the advantage of being able to cure portions of the composition that are not reached by active energy rays, the thickness of the protective layer can be, for example, 10 μm or more as a lower limit. The thickness indicates the thickness and length depending on the shape of the protective layer. For example, if the protective layer is in a sheet shape, it indicates the film thickness, and if the protective layer is in a bulk shape, it indicates the thickness and length.

[0062] <Method of manufacturing the protective layer> The method for producing a protective layer of the present invention includes a step of applying the protective layer-forming composition to a substrate to form a composition layer, and a step of irradiating the composition layer with active energy rays to cure the composition layer.

[0063] Examples of the coating method include potting, spin coating, bar coating, spray coating, dip coating, flow coating, slit coating, doctor blade coating, gravure coating, screen printing, offset printing, inkjet printing, dispenser printing, etc. Examples of the substrate include films and sheets of glass, silicon wafers, metals, plastics, etc., and three-dimensional molded products, and the shape of the substrate is not limited.

[0064] The method for curing the protective layer-forming composition is not particularly limited, and it is preferable to cure the protective layer-forming composition by irradiation with active energy rays such as electron beams, ultraviolet rays, visible light, and radiation.

[0065] Examples of light sources that can be used for the light irradiation include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet electrodeless lamps, light-emitting diodes (LEDs), xenon arc lamps, carbon arc lamps, sunlight, solid-state lasers such as YAG lasers, semiconductor lasers, and gas lasers such as argon lasers.

[0066] The exposure dose of the active energy ray should be appropriately set depending on the wavelength and intensity of the active energy ray and the composition of the polymerizable composition. For example, the exposure dose in the UV-A region is 10 to 5,000 mJ / cm. 2 It is preferable that the concentration is 30 to 3,000 mJ / cm 2 It is more preferable that the exposure dose of the active energy ray is set within the above range, thereby allowing the curing to proceed sufficiently. Note that, when a dual curing process is applied to the method for producing the protective layer, and a heating process is performed after the process of irradiating with the active energy ray, the exposure dose should be appropriately set so that the photopolymerization initiator (C) is not completely decomposed by the active energy ray.

[0067] The irradiation time of the active energy rays is not particularly limited, but is preferably 0.01 seconds to 30 minutes, and more preferably 0.1 seconds to 10 minutes. By setting the irradiation time within the above range, productivity can be improved.

[0068] In the method for producing the protective layer, a heating step may be performed before or after the step of irradiating with active energy rays. In the step of heating the polymerizable composition, examples of the heating method include heating and ventilation heating. The heating method is not particularly limited, and examples thereof include an oven, a hot plate, infrared irradiation, and electromagnetic wave irradiation. In addition, examples of the ventilation heating method include a blower drying oven.

[0069] In addition, when the composition for forming a protective layer contains the solvent, the method for producing the protective layer can include a drying step. In particular, when the step of irradiating with active energy rays is subsequently applied after the polymerizable composition is applied to a substrate, it is preferable to provide a drying step before the step of irradiating with active energy rays.

[0070] In the drying step, examples of the method for drying the solvent include heat drying, ventilation heating drying, reduced pressure drying, etc. The method for heating drying is not particularly limited, and examples thereof include an oven, a hot plate, infrared irradiation, electromagnetic wave irradiation, etc. Furthermore, examples of the method for ventilation heating drying include a blower drying oven, etc.

[0071] Furthermore, in the drying step, the temperature of the protective layer-forming composition is lower than the set drying temperature due to the latent heat of evaporation of the solvent, thereby ensuring a longer time until the protective layer-forming composition gels. Since the time until gelation is affected by factors such as the drying method and film thickness, the drying temperature and time should be appropriately set, including the selection of the solvent. For example, the drying temperature is preferably 20 to 120°C, and more preferably 40 to 100°C. The drying time is preferably 1 to 60 minutes, and more preferably 1 to 30 minutes.

[0072] In the present invention, the protective layer-forming composition can be used to form protective layers on substrates requiring surface processing, such as optical materials (e.g., silicon wafers, glass, quartz, and sapphire glass), magnetic materials, and ceramic materials. Glass applications include optical lenses, prisms, arrays, and other optical glass substrates, oscillators, and filters. Sapphire glass applications include LED substrates, projector heat sinks, watch cover glasses, polar environment windows, mechanical parts (e.g., nozzle guides), inspection jigs, and research and experimental equipment components. Magnetic materials can be used as electromagnetic wave shielding and absorbing materials. Applications of ceramic materials (particularly fine ceramic materials) include materials with electromagnetic functions (e.g., insulating, dielectric, piezoelectric, semiconductor, permanent magnet, and magnetic recording materials); materials with mechanical functions (e.g., wear resistance, cutting, and heat resistance); materials with orthopedic functions (e.g., artificial bones and artificial dental root materials); materials with optical functions (e.g., translucent materials); and materials with superconducting functions (e.g., superconducting wires and elements). [Example]

[0073] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0074] <Example> <Preparation of protective layer-forming composition> The components were mixed in the blending ratios shown in Table 1 to obtain compositions for forming protective layers of Examples 1 to 14 and Comparative Examples 1 to 3. These compositions for forming protective layers were evaluated according to the following methods.

[0075] [Evaluation method] (Curing evaluation) The protective layer-forming composition obtained above was applied to a PET film (Cosmoshine A4300, manufactured by Toyobo Co., Ltd.) that had been subjected to an easy-adhesion treatment using a bar coater to form a uniform coating film with a thickness of approximately 30 μm. Next, the coating was irradiated with ultraviolet light (1.8 J / cm ) using a 385 nm LED light source. 2 ) to obtain a cured film. The evaluation was ◯, which was considered to be a pass. Good: No fingerprints are left on the coating when the light-irradiated area is touched with a finger. △: Fingerprints are left on the coating film when the light-irradiated area is touched with a finger. ×: When the irradiated area was touched with a finger, the coating film (coating liquid) adhered to the finger.

[0076] (Thick film curing evaluation) The protective layer-forming composition obtained above was applied to a release-treated PET film (TD06UV0145, manufactured by TOMOEGAWA) using a spacer to form a uniform coating film with a thickness of 500 μm. Next, the coating film was irradiated with ultraviolet light (1.8 J / cm) using a 385 nm LED light source. 2 When the release film was peeled off from the cured film, the interface between the cured film and the release film was visually observed. ◯: The release film can be peeled off smoothly, and no uncured protective layer-forming composition is attached to the release film. ×: The release film cannot be peeled off smoothly, or uncured protective layer-forming composition remains on the release film.

[0077] (Cure shrinkage evaluation) The protective layer-forming composition obtained above was applied to a PET film (Cosmoshine A4300, manufactured by Toyobo Co., Ltd.) that had been subjected to an easy-adhesion treatment using a bar coater to form a uniform coating film with a thickness of approximately 30 μm. Next, the coating was irradiated with ultraviolet light (1.8 J / cm ) using a 385 nm LED light source. 2 ) to obtain a cured film. The prepared cured film (3 cm square) was placed on a flat desk, and the floating heights of the four sides were measured and the total value was calculated. If the average floating height due to warping of the protective layer caused by cure shrinkage is 10 mm or less, it can be determined that cure shrinkage has been suppressed. The evaluation is ◯ or △, with ◯ being more preferable. ○: The total value is 3 mm or less. △: The total value is greater than 3 mm and less than or equal to 10 mm. ×: The total value is greater than 10 mm.

[0078] (Adhesion evaluation) The protective layer-forming composition obtained above was applied to a PET film (Cosmoshine A4300, manufactured by Toyobo Co., Ltd.) that had been subjected to an easy-adhesion treatment using a bar coater to produce a uniform coating film with a thickness of approximately 100 μm. Next, the coating was exposed to ultraviolet light (illuminance 5 W / cm ) using a 385 nm LED light source. 2 ) or by heating at 150°C for a predetermined time, a cured film was obtained. The adhesion of the produced cured film was evaluated using the cross-cut test method according to the following criteria. Adhesion was judged to be good if peeling did not exceed 5% of the total. A rating of ◯ was considered to be pass. ◯: There is only small peeling of the coating at the intersections of the cuts, and the peeling does not exceed 5% of the total. △: The cured film peeled off at the intersections or partially along the cut lines. Peeling was 5% or more but less than 35%. ×: The cured film peeled off entirely along the cut line or the entire cured film. Peeling was 35% or more.

[0079] Details of the abbreviations and other information listed in Table 1 are as follows: IBXA: Isobornyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) ECA: Ethyl carbitol acrylate (Tokyo Chemical Industry Co., Ltd.) UV-7600B: Urethane acrylate (Mitsubishi Chemical) A-TMPT: Trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) Compound 10: Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (manufactured by IGM Resins BV) UV-3510: Polyether-modified polydimethylsiloxane (manufactured by BYK Japan)

[0080] Compound 1 listed in Table 1 was synthesized according to the method described in International Publication No. 2020 / 067118, compounds 2 to 7 were synthesized according to the method described in International Publication No. 2023 / 054225, and compound 8 was synthesized according to the method described in International Publication No. 2018 / 221177. The synthesized compounds were identified by EI-MS and H-NMR. Details of compounds 1 to 9 are shown in Table 2.

[0081] [Table 1]

[0082] [Table 2]

[0083] As shown in Table 1, the protective layer-forming compositions of each Example exhibited low viscosity and excellent curability, reduced cure shrinkage, and good adhesion. On the other hand, Comparative Example 1 did not contain one or more compounds selected from the group consisting of general formulas (1), (2), (3), and (4), resulting in poor curability and thick-film curability. Comparative Example 2 contained a large amount of polyfunctional acrylate, resulting in poor cure shrinkage and adhesion. Comparative Example 3 contained a small amount of polyfunctional acrylate, resulting in poor curability and thick-film curability.

Claims

1. A composition for forming a protective layer, comprising a monofunctional (meth)acrylate (A), a polyfunctional (meth)acrylate (B), and a photopolymerization initiator (C), The photopolymerization initiator (C) contains one or more compounds selected from the group consisting of the following general formulas (1), (2), (3), and (4): A composition for forming a protective layer, characterized in that the polyfunctional (meth)acrylate is present in an amount of 0.5 parts by weight or more and 30 parts by weight or less relative to 100 parts by weight of the monofunctional (meth)acrylate, and the viscosity of the composition for forming a protective layer at 25°C is 100 mPa·s or less. General formula (1): 【Chemical 1】 (In general formula (1), R １ , R ２ , R ３ and R ４ independently represent a methyl group or an ethyl group, R ５ represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, and R ６ are independent substituents each representing an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a chlorine atom, and n represents an integer of 0 to 2. General formula (2): 【Chemistry 2】 (In general formula (2), R ７ and R ８ R independently represents a methyl group or an ethyl group. ９ represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group. X represents a group represented by the following general formula (2-a): Ar １ , Ar ２ , Ar ３ or Ar ４ and n is an integer of 0 to 2. A triazine derivative having a peroxide bond represented by the formula: 【Chemistry 3】 (In general formula (2-a), m represents an integer of 0 to 3. R １０ are independent substituents, and are alkyl groups having 1 to 18 carbon atoms; １１ represents a substituent represented by —Y—, a nitro group, or a cyano group. The Y represents an oxygen atom or a sulfur atom. １１ represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a hydroxyl group at a terminal in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. １０ is two adjacent groups of the general formula (2-b): R １１ -Y- may form a 5- or 6-membered ring. General formula (3): 【Chemistry 4】 (In general formula (3), R １２ and R １３ are independently a methyl group or an ethyl group, R １４ represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group; R １５ represents an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms, an optionally substituted acyl group having 1 to 20 carbon atoms, -Y-R, or -N-RR', where Y represents an oxygen atom or a sulfur atom, and R and R' independently represent a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, or an optionally substituted heterocyclic ring-containing group having 2 to 20 carbon atoms. Ar represents the following general formula (3-a): Ar ５ , Ar ６ , Ar ７ or Ar ８ The triazine derivative having a peroxide bond represented by the formula: 【Chemistry 5】 (In general formula (3-a), m represents an integer of 0 to 3. R １６ are independent substituents, and are alkyl groups having 1 to 18 carbon atoms; １７ represents a substituent represented by —Y—, a nitro group, or a cyano group. The Y represents an oxygen atom or a sulfur atom. １７ represents a hydrocarbon group having 1 to 18 carbon atoms which may have one or more of an ether bond, a thioether bond, and a hydroxyl group at a terminal in the carbon skeleton, an aromatic hydrocarbon group having 6 to 9 carbon atoms which may have an alkyl group, or an acyl group having 1 to 8 carbon atoms. １６ is two adjacent groups of the general formula (3-b): R １７ -Y- may form a 5- or 6-membered ring. A compound represented by general formula (4): 【Chemistry 6】

2. The composition for forming a protective layer according to claim 1 , further comprising a leveling agent (D).

3. A protective layer formed from the composition for forming a protective layer according to claim 1 or 2.

4. 3. A method for producing a protective layer, comprising: a step of applying the protective layer-forming composition according to claim 1 or 2 to a substrate to form a composition layer; and a step of irradiating the composition layer with active energy rays to cure the composition layer.

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