Curable composition and cured product

Abstract

The present invention addresses the problem of providing a curable composition that cures rapidly without the use of a tin-based curing catalyst and is capable of forming a cured product that exhibits superior storage stability and mechanical properties, and a curable composition that exhibits superior adhesion properties.　A curable composition according to the present invention is characterized by containing: a (meth)acrylic polymer (A) that has a group represented by formula (1), has a number average molecular weight (Mn) of at least 1000, and contains at least 500 ppm elemental silicon; and a silane coupling agent (B) that is represented by formula (2) and has a molecular weight of less than 1000. Formula (1): -X-CH2-SiR1 3 Formula (2): Y-CH2-SiR1 3

Description

[Technical Field]

[0001] The present invention relates to a curable composition and a cured product. [Background technology]

[0002] Polymers containing reactive silicon groups in their molecules are known as compositions that crosslink and cure through the formation of siloxane bonds accompanied by hydrolysis of silyl groups due to moisture in the atmosphere or on the substrate. Among these, polymers containing reactive silicon groups such as alkoxysilyl groups are widely used as adhesives, sealants, paints, etc. in construction and building material-related applications, automotive-related applications, etc.

[0003] In particular, it is known that by using a polyoxyalkylene polymer or a (meth)acrylic polymer having a reactive silicon group of a specific structure, a curable composition having fast curing properties and excellent adhesive properties and storage stability can be obtained (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-136685 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-101499 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-202863 Summary of the Invention [Problem to be solved by the invention]

[0005] Curable compositions containing polymers having reactive silicon groups in the molecule are usually cured using a catalyst such as a tin-based compound to accelerate the curing reaction, but the use of tin-based compounds is undesirable from the viewpoints of environmental impact and toxicity to the human body.

[0006] The composition described in Patent Document 1 above contains a tin compound as a condensation catalyst. On the other hand, the curable compositions described in Patent Documents 2 and 3 are characterized by being well cured without using a tin-based compound. However, the curable composition disclosed in Patent Document 2 has a polymer having a silyl group represented by a specific formula that is highly reactive, and the reaction proceeds even with moisture in the air. Therefore, the curable composition must be stored in an airtight container or the like that blocks air. Furthermore, after being removed from the storage container or the like, the curable composition must be used up or discarded, resulting in the problem of poor storage stability.

[0007] An object of the present invention is to provide a curable composition that cures quickly without the use of a tin-based curing catalyst and can form a cured product that has excellent storage stability and mechanical properties, or a curable composition that has excellent adhesiveness. [Means for solving the problem]

[0008] The present invention relates to, for example, the following [1] to [7].

[0009] [1] A (meth)acrylic polymer (A) having a group represented by formula (1), having a number average molecular weight (Mn) of 1,000 or more, and containing 500 ppm or more of silicon element; A curable composition containing a silane coupling agent (B) represented by formula (2) and having a molecular weight of less than 1,000.

[0010] Formula (1):-X-CH2-SiR 1 3 [In formula (1), R 1 are each independently an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group, and R 1 at least one of the groups is an alkoxy group or a hydroxyl group; X is —O—, —COO—, —S—, —N(R 2 )-, -CH(OH)-CH2-O-, -O-CO-NH- or -N(R 2 )-CO-N(R 3 )-, and R 2 and R 3is a hydrogen atom, a hydrocarbon group, or a halogenated hydrocarbon group, and R 2 and R 3 may be the same or different.] Formula (2): Y-CH2-SiR 1 3 [In formula (2), R 1 has the same meaning as in formula (1); and Y is a (meth)acryloyl group, an alkoxy group having 1 to 20 carbon atoms, a mercapto group, or an isocyanate group.] [2] The curable composition according to [1], comprising 0.1 to 20 parts by mass of (B) relative to 100 parts by mass of the (meth)acrylic polymer (A).

[0011] [3] The curable composition according to [1] or [2], wherein the (meth)acrylic polymer (A) has a group represented by the formula (1) at least at an end thereof.

[0012] [4] The curable composition according to any one of [1] to [3], wherein the (meth)acrylic polymer (A) has a glass transition temperature (Tg) of −20° C. or lower.

[0013] [5] The curable composition according to any one of [1] to [4], wherein the (meth)acrylic polymer (A) has a number average molecular weight of 1,000 to 100,000.

[0014] [6] The curable composition according to any one of [1] to [5], comprising 0.05 to 10 parts by mass of an aminosilane compound (C) represented by the following formula (3) per 100 parts by mass of the (meth)acrylic polymer (A):

[0015] Formula (3):R 4 2-N-(CH2) n -SiR 1 3 [In formula (3), n is an integer of 1 to 6; R 1 is the same as formula (1); R 4are each independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a group in which at least one hydrogen atom of the hydrocarbon group has been substituted with a group selected from the group consisting of an unsubstituted amino group, a substituted amino group, and an alkoxysilyl group. [7] A cured product obtained from the curable composition according to any one of [1] to [6]. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a curable composition that can be cured without using a tin-based curing catalyst and can form a cured product that has excellent storage stability and mechanical properties, or a curable composition that has excellent adhesiveness even after long-term storage. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be specifically described below.

[0018] The curable composition of the present invention (hereinafter also referred to as "the composition of the present invention") contains a (meth)acrylic polymer (A) and a silane coupling agent (B), which will be explained below.

[0019] In this specification, (meth)acrylic is used as a general term for acrylic and methacrylic and may be either acrylic or methacrylic, (meth)acrylate is used as a general term for acrylate and methacrylate and may be either acrylate or methacrylate, and (meth)acryloyl is used as a general term for acryloyl and methacryloyl and may be either acryloyl or methacryloyl.

[0020] [(Meth)acrylic polymer (A)] The (meth)acrylic polymer (A) (hereinafter also referred to as "polymer (A)") is a polymer having a group represented by formula (1), having a number average molecular weight (Mn) of 1,000 or more, and containing 500 ppm or more of silicon element.

[0021] Formula (1):-X-CH2-SiR 1 3 In formula (1), R 1are each independently an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group, and R 1 at least one of the groups is an alkoxy group or a hydroxyl group; X is —O—, —COO—, —S—, —N(R 2 )-, -CH(OH)-CH2-O-, -O-CO-NH- or -N(R 2 )-CO-N(R 3 )-, and R 2 and R 3 is a hydrogen atom, a hydrocarbon group, or a halogenated hydrocarbon group, and R 2 and R 3 may be the same or different.

[0022] Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, a 1-methylpentyl group, a 4-methyl-2-pentyl group, a 3,3-dimethylbutyl group, a 2-ethylbutyl group, an n-heptyl group, a 1-methylhexyl group, an n-octyl group, an isooctyl group, a 1-methylheptyl group, a 2-ethylhexyl group, a 2-propylpentyl group, an n-nonyl group, Examples of the alkyl group include straight-chain and branched alkyl groups such as 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, 3,5,5-trimethylhexyl, n-decyl, n-undecyl, 1-methyldecyl, n-dodecyl, n-tridecyl, 1-hexylheptyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and n-eicosyl, and are preferably alkyl groups having 1 to 10 carbon atoms, more preferably alkyl groups having 1 to 3 carbon atoms. The alkyl groups may be straight-chain or branched.

[0023] Examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, an n-pentyloxy group, an isopentyloxy group, a neopentyloxy group, an n-hexyloxy group, a 1-methylpentyloxy group, a 4-methyl-2-pentyloxy group, a 3,3-dimethylbutyloxy group, a 2-ethylbutyloxy group, an n-heptyloxy group, a 1-methylhexyloxy group, an n-octyloxy group, an isooctyloxy group, a 1-methylheptyloxy group, a 2-ethylhexyloxy group, a 2-propylpentyloxy group, Examples of such alkoxy groups include linear and branched alkoxy groups such as n-nonyloxy, 2,2-dimethylheptyloxy, 2,6-dimethyl-4-heptyloxy, 3,5,5-trimethylhexyloxy, n-decyloxy, n-undecyloxy, 1-methyldecyloxy, n-dodecyloxy, n-tridecyloxy, 1-hexylheptyloxy, n-tetradecyloxy, n-pentadecyloxy, n-hexadecyloxy, n-heptadecyloxy, n-octadecyloxy, and n-eicosyloxy, and are preferably alkoxy groups having 1 to 10 carbon atoms, and more preferably 1 to 3 carbon atoms. The alkoxy group may be linear or branched.

[0024] R 2 and R 3 Examples of the hydrocarbon group in the formula (I) include alkyl groups having 1 to 18 carbon atoms, preferably 1 to 3 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, 2-ethylhexyl, n-octyl, and isooctyl groups; cycloalkyl groups having 3 to 18 carbon atoms, preferably 5 to 8 carbon atoms, such as cyclopentyl and cyclohexyl groups; alkenyl groups having 2 to 18 carbon atoms, preferably 2 to 5 carbon atoms, such as vinyl, allyl, 3-butenyl, and 5-hexenyl groups; and aryl groups having 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms, such as phenyl, naphthyl, and anthryl groups.

[0025] R 2 and R 3The halogenated hydrocarbon group in the formula (I) is a group in which at least some of the hydrogen atoms constituting the hydrocarbon group have been substituted with halogen atoms. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0026] R 2 and R 3 is preferably a hydrogen atom or a hydrocarbon group, more preferably a hydrocarbon group.

[0027] -SiR 1 Examples of the group represented by 3 include a dimethylmethoxysilyl group, a dimethylethoxysilyl group, a methyldimethoxysilyl group, a methyldiethoxysilyl group, a trimethoxysilyl group, a triethoxysilyl group, a dimethylisopropoxysilyl group, a methyldiisopropoxysilyl group, and a triisopropoxysilyl group.

[0028] From the viewpoint of curability and mechanical properties, polymer (A) has a group represented by formula (1) and contains 500 ppm or more, preferably 1,000 to 20,000 ppm, and more preferably 1,500 to 10,000 ppm of silicon element. The term "ppm" refers to wt ppm. The silicon element content derived from the group represented by formula (1) in polymer (A) can be calculated from the charge ratio, but can also be measured by ICP atomic emission spectroscopy. Details are described in the Examples section.

[0029] <(Meth)acrylic acid alkyl ester (a1)> The polymer (A) is preferably a polymer of a polymerizable monomer component containing a (meth)acrylic acid alkyl ester (a1) (hereinafter also referred to as "monomer (a1)") having an alkyl group with a carbon number of 1 to 12. That is, the polymer (A) preferably has a structural unit derived from the monomer (a1).

[0030] The alkyl group may be straight or branched.

[0031] Examples of the monomer (a1) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, and lauryl (meth)acrylate.

[0032] The monomer (a1) can be used alone or in combination of two or more.

[0033] The proportion of the monomer (a1) in the polymerizable monomer components constituting the polymer (A) is preferably 20% by mass or more, more preferably 20 to 85% by mass, even more preferably 20 to 75% by mass, and particularly preferably 22 to 55% by mass. The polymer (A) may have structural units derived from the monomer (a1) in the same range among all structural units. When a (meth)acrylic acid alkyl ester (a1) having an alkyl group with 8 to 12 carbon atoms is used in the above range, a (meth)acrylic polymer having excellent mechanical properties can be obtained.

[0034] <Hydrolyzable silyl group-containing (meth)acryloyl monomer (a2)> It is preferable that the polymer (A) further contains a structural unit derived from a hydrolyzable silyl group-containing (meth)acryloyl monomer (a2) (hereinafter also referred to as "monomer (a2)") that is copolymerizable with the monomer (a1) and has a group represented by formula (1).

[0035] As the monomer (a2), for example, a compound represented by formula (a2-1) is preferable.

[0036] [ka] In formula (a2-1), R a is a hydrogen atom or a methyl group, and R 1 is R in Eq. (1)1 is synonymous with.

[0037] Examples of the compound represented by formula (a2-1) include (meth)acryloxy group-containing silanes such as (meth)acryloxymethyldimethylmethoxysilane, (meth)acryloxymethyldimethylethoxysilane, ((meth)acryloxymethyl)methyldimethoxysilane, ((meth)acryloxymethyl)methyldiethoxysilane, (meth)acryloxymethyltrimethoxysilane, and (meth)acryloxymethyltriethoxysilane.

[0038] Monomer (a2) includes a monomer in which OCN-CH2-SiR is bonded to a hydroxy group of a hydroxyalkyl (meth)acrylate such as 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, or to an amino group of an aminoalkyl (meth)acrylate such as 2-aminoethyl (meth)acrylate. 1 The compound represented by 3 (R 1 The symbol OCN—CH—SiR has the same meaning as the symbol in formula (1). 1 Specific examples of the compound represented by 3 will be described later.

[0039] The monomer (a2) can be used alone or in combination of two or more.

[0040] The proportion of monomer (a2) in the polymerizable monomer components constituting polymer (A) is preferably 0.01 to 10 mass%, more preferably 0.1 to 5 mass%. Polymer (A) can have structural units derived from monomer (a2) in the same range among all structural units. When monomer (a2) is used in the above range, a group represented by formula (1) can be introduced into polymer (A). Therefore, the obtained polymer (A) has appropriate crosslinkability and is suitable for applications in which a crosslinked product is formed.

[0041] <Other Monomers (a3)> The polymer (A) may further contain a structural unit derived from a monomer (a3) ​​other than the monomers (a1) and (a2) within the scope of the present invention.

[0042] Examples of the other monomers (a3) ​​include: (meth)acrylic acid alkyl esters having an alkyl group carbon number of 13 or more, preferably an alkyl group carbon number of 22, such as n-tridecyl (meth)acrylate, isodecyl (meth)acrylate, n-myristyl (meth)acrylate, isomyristyl (meth)acrylate, n-pentadecyl (meth)acrylate, isopentadecyl (meth)acrylate, n-cetyl (meth)acrylate, isocetyl (meth)acrylate, n-heptadecyl (meth)acrylate, isoheptadecyl (meth)acrylate, n-stearyl (meth)acrylate, isostearyl (meth)acrylate, n-nonadecyl (meth)acrylate, isononadecyl (meth)acrylate, n-eicosyl (meth)acrylate, and isoeicosyl (meth)acrylate; (meth)acrylates containing an alicyclic hydrocarbon group or an aromatic hydrocarbon group, such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, and phenyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as methoxymethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; polyalkylene glycol (meth)acrylates such as methoxypolyethylene glycol mono(meth)acrylate, ethoxypolyethylene glycol mono(meth)acrylate, octoxypolyethylene glycol mono(meth)acrylate, lauroxypolyethylene glycol mono(meth)acrylate, stearoxypolyethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; (meth)acrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid; carboxy group-containing monomers such as carboxy group-containing (meth)acrylates such as β-carboxyethyl (meth)acrylate, 5-carboxypentyl (meth)acrylate, succinic acid mono(meth)acryloyloxyethyl ester, and ω-carboxypolycaprolactone mono(meth)acrylate; Monomers containing an acid anhydride group, such as phthalic anhydride and maleic anhydride; dialkylaminoalkyl (meth)acrylates such as 2-dimethylaminoethyl (meth)acrylate and 2-diethylaminoethyl (meth)acrylate; (Meth)acrylamides; N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, and N-hexyl(meth)acrylamide; amide group-containing monomers such as N,N-dialkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide; Cyano group-containing monomers such as (meth)acrylonitrile; Nitrogen-based heterocycle-containing monomers such as N-vinylpyrrolidone, N-vinylmorpholine, N-vinylcaprolactam, (meth)acryloylmorpholine, N-cyclohexylmaleimide, N-phenylmaleimide, N-laurylmaleimide, and N-benzylmaleimide; Styrene derivatives such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, p-chloromethylstyrene, p-methoxystyrene, p-tert-butoxystyrene, divinylbenzene, and indene; vinyl ester compounds such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl benzoate, and vinyl cinnamate;

[0043] Among the other monomers (a3), (meth)acrylic acid alkyl esters other than the monomer (a1) and polyalkylene glycol (meth)acrylates are preferred, and (meth)acrylic acid alkyl esters other than the monomer (a1) are more preferred.

[0044] The other monomers (a3) ​​can be used alone or in combination of two or more.

[0045] The proportion of the other monomer (a3) ​​in the polymerizable monomer components constituting the polymer (A) is preferably 1 to 65 mass %, more preferably 5 to 60 mass %. The polymer (A) may have structural units derived from the other monomer (a3) ​​in the total structural units in a similar range.

[0046] <Mercapto group-containing compound (d)> During the production of the polymer (A), a mercapto group-containing compound (d) may be used as a chain transfer agent.

[0047] The mercapto group-containing compound (d) functions as a chain transfer agent due to its functional group (-SH) with high chain transfer properties in radical polymerization. When polymerizable monomer components are polymerized in the presence of the mercapto group-containing compound (d), a structural unit derived from the mercapto group-containing compound (d), particularly a mercapto group-containing compound having a group represented by formula (1), is used. The group represented by formula (1) can be introduced into the molecular chain terminal of the polymer. Furthermore, by introducing the mercapto group-containing compound (d) represented by formula (1) into a polymer having a polymerizable unsaturated group via an ene-thiol reaction, the group represented by formula (1) can also be introduced into the polymer. Curable compositions using a polymer (A) having a group represented by formula (1) at the molecular chain terminal exhibit excellent mechanical properties.

[0048] When the monomer (a2) is used, the group represented by formula (1) in the monomer (a2) and the group represented by formula (1) in the mercapto group-containing compound (d) may be the same or different.

[0049] The mercapto group-containing compound (d) is preferably a compound represented by formula (d-1).

[0050] Formula (d-1): HS-CH2-SiR 1 3 In formula (d-1), R 1 is R in equation (1). 1 is synonymous with.

[0051] Among the mercapto group-containing compounds (d), examples of compounds represented by formula (d-1) include mercaptomethyldimethylmethoxysilane, mercaptomethyldimethylethoxysilane, mercaptomethyldimethylisopropoxysilane, mercaptomethylmethyldimethoxysilane, mercaptomethylmethyldiethoxysilane, mercaptomethylmethyldiisopropoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, and mercaptomethyltriisopropoxysilane. Among these, mercaptomethyldimethylmethoxysilane, mercaptomethylmethyldimethoxysilane, mercaptomethyltrimethoxysilane, and mercaptomethyltriethoxysilane are preferred. By using a compound represented by formula (d-1), a group represented by formula (1) can be introduced into the molecular chain terminal of the polymer (A).

[0052] Other mercapto group-containing compounds (d) include, for example, n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, lauryl mercaptan, 2-mercaptoethanol, 3-mercapto-1,2-propanediol, 2,2-mercaptopropyl dimethyl methoxysilane, mercaptopropyl dimethyl ethoxysilane, mercaptopropyl methyl dimethoxysilane, mercaptopropyl methyl diethoxysilane, mercaptopropyl trimethoxysilane, and mercaptopropyl triethoxysilane.

[0053] The compound (d) can be used alone or in combination of two or more.

[0054] The mercapto group-containing compound (d) is used in an amount of preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, per 100 parts by mass of the total of the polymerizable monomer components. In this embodiment, the number average molecular weight of the polymer (A) can be adjusted to an appropriate range.

[0055] <Production of Polymer (A)> The polymer (A) can be obtained by various polymerization methods, and the method is not particularly limited, but it is preferable to obtain it by, for example, the following method. Note that the methods (i) to (iv) may be used in any combination.

[0056] (i) A method of copolymerizing a monomer (a2) having a polymerizable unsaturated group and a group represented by formula (1) with the above-mentioned monomer (a1) having a (meth)acrylic structure.

[0057] (ii) A method of polymerizing a monomer (a1) having a (meth)acrylic structure in the presence of a mercapto group-containing compound (d) having a group represented by formula (1) as a chain transfer agent.

[0058] (iii) A method of reacting a polymer having a reactive functional group obtained by copolymerizing a compound having a polymerizable unsaturated group and a reactive functional group (e.g., a hydroxy group, an isocyanate group, or an amino group) and a monomer component including monomer (a1) with a compound (e) having a group that undergoes an addition reaction with the reactive functional group and that can introduce a group represented by formula (1) into the polymer by the addition reaction.

[0059] Examples of the compound (e) include compounds represented by formula (e-1) and formula (e-2) (hereinafter also referred to as "compound (e-1)" and "compound (e-2)", respectively).

[0060] Formula (e-1):OCN-CH2-SiR 1 3 R 1 has the same meaning as the same symbol in formula (1).

[0061] Examples of the compound (e-1) include 1-isocyanatemethyldimethylmethoxysilane, 1-isocyanatemethyldimethylethoxysilane, 1-isocyanatemethyldimethylisopropoxysilane, (1-isocyanatemethyl)methyldimethoxysilane, (1-isocyanatemethyl)methyldiethoxysilane, (1-isocyanatemethyl)methyldiisopropoxysilane, 1-isocyanatemethyltrimethoxysilane, 1-isocyanatemethyltriethoxysilane, and 1-isocyanatemethyltriisopropoxysilane. Among these, 1-isocyanatemethyldimethylmethoxysilane, (1-isocyanatemethyl)methyldimethoxysilane, 1-isocyanatemethyltrimethoxysilane, and 1-isocyanatemethyltriethoxysilane are preferred.

[0062] Formula (e-2):R 4 -CH2-SiR 1 3 R 1 is the same as the same symbol in formula (1), and R 4 is a glycidyloxy group, an amino group, an alkylamino group, an (aminoalkyl)amino group, an (N,N-dialkylaminoalkyl)amino group, or a halogenated hydrocarbon group.

[0063] Examples of the compound (e-2) include aminomethyltrimethoxysilane, aminomethyltriethoxysilane, (aminoethylamino)methyltrimethoxysilane, (N,N-dimethylamino)ethylaminomethyltrimethoxysilane, and glycidyloxymethyltrimethoxysilane.

[0064] The compound (e) can be used alone or in combination of two or more kinds.

[0065] The compound (e) is preferably used in an amount of 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, based on 100 parts by mass of the total of the polymerizable monomer components.

[0066] (iv) A method in which the monomer (a1) is polymerized by a living polymerization method, a functional group such as an alkenyl group or a hydroxyl group is introduced into the molecular chain terminal, and then the obtained polymer is reacted with the compound (d) or the compound (e), etc.

[0067] The polymer (A) can be produced by utilizing known polymerization methods such as cationic polymerization, anionic polymerization, and radical polymerization, as in the above-mentioned methods (i) to (iv). The method is not particularly limited, but radical polymerization is preferred from the viewpoints of versatility of monomers and industrial productivity. Examples of radical polymerization methods include living radical polymerization, which can introduce a specific functional group (e.g., a group represented by formula (1)) into a controlled position such as an end, and free radical polymerization, which copolymerizes predetermined monomer units using a polymerization initiator.

[0068] Living polymerization methods include living cationic polymerization, living anionic polymerization, and living radical polymerization, but living radical polymerization is preferred from the perspective of industrial productivity. Examples of living radical polymerization methods that can be used include atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer (RAFT) polymerization, nitroxide-mediated polymerization (NMP), organotellurium-mediated polymerization (TERP), and iodine-mediated polymerization (IRP). By selecting the reaction conditions, polymers with terminal functional groups can be obtained.

[0069] In the free radical polymerization method, for example, a reaction vessel is charged with polymerizable monomer components and, if necessary, a mercapto group-containing compound (d), and a polymerization initiator is added, followed by reaction at a reaction temperature of about 40 to 90°C for 2 to 20 hours. In the reaction, a polymerization solvent may be added as necessary. For example, the polymerization is carried out under an inert gas atmosphere such as nitrogen gas. Furthermore, during the polymerization reaction, the polymerizable monomer components, polymerization initiator, chain transfer agent, and polymerization solvent may be appropriately added.

[0070] Examples of polymerization initiators include azo compound-based polymerization initiators, peroxide-based polymerization initiators, and photoradical polymerization initiators. It is more preferable not to use a metal catalyst. Polymer (A) produced using such a polymerization initiator does not contain any metal components derived from the catalyst, and therefore, can improve the inhibition of crosslinking reactions and coloration. Furthermore, since depolymerization reactions caused by metal components can be suppressed, a cured product with excellent durability for use in various applications can be provided.

[0071] Examples of the azo compound polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, ... Examples of suitable azobis(2-amidinopropane) dihydrochloride include 2,2'-azobis(N,N'-dimethyleneisobutylamidine), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-azobis(isobutylamide) dihydrate, 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobis(2-cyanopropanol), dimethyl-2,2'-azobis(2-methylpropionate), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

[0072] Examples of peroxide polymerization initiators include t-butyl hydroperoxide, cumene hydroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propanol, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propanol. propane, 2,2-bis(4,4-di-t-amylperoxycyclohexyl)propane, 2,2-bis(4,4-di-t-octylperoxycyclohexyl)propane, 2,2-bis(4,4-di-α-cumylperoxycyclohexyl)propane, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)butane, and 2,2-bis(4,4-di-t-octylperoxycyclohexyl)butane.

[0073] As the photoradical polymerization initiator, compounds conventionally used as photoradical polymerization initiators are preferred, for example, benzoin-based initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1 ... Acetophenone initiators such as cyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, and N,N-dimethylaminoacetophenone; anthraquinone initiators such as 2-methylanthraquinone, 1-chloroanthraquinone, and 2-amylanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, and 2-isopropylthioxanthone; thioxanthone-based initiators such as acetophenone dimethyl ketal and benzyl methyl ketal; benzophenone-based initiators such as benzophenone, methylbenzophenone, 4-phenylbenzophenone, 2,4,6-trimethylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Michler's ketone and 4-benzoyl-4'-methyldiphenyl sulfide; 2,4 Acylphosphine oxide initiators such as bis(2,6-dimethoxybenzoyl)-2,4,4'-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; oxime ester initiators such as 1-[4-(phenylthio)phenyl]octane-1,2-dione 2-(O-benzoyloxime); camphorquinone and α-hydroxyketones.

[0074] The photoradical polymerization initiator may be used alone or in combination of two or more kinds.

[0075] The photoradical polymerization initiator may be combined with a sensitizer, and examples of the sensitizer include anthracene compounds such as 9,10-dibutoxyanthracene and 9,10-bis(acyloxy)anthracene.

[0076] The polymerization initiators can be used alone or in combination.

[0077] The polymerization initiator may be added successively multiple times.

[0078] The amount of the polymerization initiator used is usually 0.001 to 2 parts by mass, and preferably 0.002 to 1 part by mass, relative to 100 parts by mass of the polymerizable monomer component. By using the polymerization initiator within the above range, the number average molecular weight of the polymer (A) can be adjusted within an appropriate range.

[0079] The polymerization solvent is preferably an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; ethers such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenylethyl ether, and diphenyl ether; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, and chlorobenzene; esters such as ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, acetylacetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; and sulfoxides such as dimethyl sulfoxide and sulfolane.

[0080] The polymerization solvent may be used alone or in combination of two or more kinds.

[0081] <Physical properties of polymer (A)> The number average molecular weight (Mn) of the polymer (A) is preferably 1,000 or more, more preferably 3,000 or more, and even more preferably 5,000 or more, from the viewpoint of the viscosity of the polymer and the mechanical properties of the resulting cured product, and is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 40,000 or less, from the viewpoint of the viscosity of the polymer.

[0082] The number average molecular weight (Mn) is measured by gel permeation chromatography (GPC).

[0083] The glass transition temperature (Tg) of the polymer (A) is preferably −20° C. or lower, more preferably −90 to −25° C., and even more preferably −80 to −30° C. This embodiment is preferred from the viewpoint of low viscosity and excellent handleability. Tg is determined by differential scanning calorimetry (DSC).

[0084] Details of the measurement conditions for GPC and DSC will be described in the Examples section below.

[0085] <Content of polymer (A)> The composition of the present invention may contain one or more polymers (A).

[0086] The composition of the present invention preferably contains a total of 5% by mass or more of the polymer (A), more preferably 8 to 95% by mass, and even more preferably 10 to 90% by mass.

[0087] [Silane coupling agent (B)] The composition of the present invention contains a silane coupling agent (B) in addition to the polymer (A).

[0088] The silane coupling agent (B) acts as a dehydrating agent in the composition of the present invention.

[0089] Since the polymer (A) has a group represented by formula (1), the composition of the present invention undergoes curing without the use of a tin-based curing catalyst. However, since the polymer (A) having a group represented by formula (1) alone is highly reactive and the reaction proceeds even in the presence of moisture in the air, the reaction of the polymer (A) is suppressed by including a silane coupling agent (B) represented by formula (2) in the curable composition, and a curable composition having excellent storage stability and excellent adhesion even after long-term storage can be obtained.

[0090] The dehydrating effect of the silane coupling agent (B) is exerted by the combination of the polymer (A) having a group represented by formula (1) and the polymer (B) having a group represented by formula (2).

[0091] The silane coupling agent (B) is represented by formula (2).

[0092] Formula (2): Y-CH2-SiR 1 3 In formula (2), R 1 has the same meaning as in formula (1); Y is a (meth)acryloyl group, an alkoxy group having 1 to 20 carbon atoms, a mercapto group, or an isocyanate group.

[0093] Alkoxy groups with 1 to 20 carbon atoms and -SiR 1 Examples of the group represented by 3 include the same groups as those described in the section on polymer (A).

[0094] In the silane coupling agent (B), examples of the silane coupling agent in which Y is a (meth)acryloyl group include (meth)acryloxymethyldimethylmethoxysilane, (meth)acryloxymethyldimethylethoxysilane, ((meth)acryloxymethyl)methyldimethoxysilane, ((meth)acryloxymethyl)methyldiethoxysilane, (meth)acryloxymethyltrimethoxysilane, and (meth)acryloxymethyltriethoxysilane.

[0095] In the silane coupling agent (B), examples of the silane coupling agent in which Y is an alkoxy group having 1 to 20 carbon atoms include methoxymethyltrimethoxysilane, ethoxymethyltrimethoxysilane, n-propyloxymethyltrimethoxysilane, isopropyloxymethyltrimethoxysilane, n-butyloxymethyltrimethoxysilane, isobutyloxymethyltrimethoxysilane, n-pentyloxymethyltrimethoxysilane, isopentyloxymethyltrimethoxysilane, neopentyloxymethyltrimethoxysilane, n-hexyloxymethyltrimethoxysilane, 1-methylpentyloxymethyltrimethoxysilane, 4-methyl-2-pentyloxymethyltrimethoxysilane, Trimethoxysilane, 3,3-dimethylbutyloxymethyltrimethoxysilane, 2-ethylbutyloxymethyltrimethoxysilane, n-heptyloxymethyltrimethoxysilane, 1-methylhexyloxymethyltrimethoxysilane, n-octyloxymethyltrimethoxysilane, isooctyloxymethyltrimethoxysilane, 1-methylheptyloxymethyltrimethoxysilane, 2-ethylhexyloxymethyltrimethoxysilane, 2-propylpentyloxymethyltrimethoxysilane, n-nonyloxymethyltrimethoxysilane, 2,2-dimethylheptyloxymethyltrimethoxysilane, 2,6-dimethyl-4-heptyloxymethyltrimethoxysilane, 3,5,5-Trimethylhexyloxymethyltrimethoxysilane, n-Decyloxymethyltrimethoxysilane, n-Undecyloxymethyltrimethoxysilane, 1-Methyldecyloxymethyltrimethoxysilane, n-Dodecyloxymethyltrimethoxysilane, n-Tridecyloxymethyltrimethoxysilane, 1-Hexylheptyloxymethyltrimethoxysilane, n-Tetradecyloxymethyltrimethoxysilane, n-Pentadecyloxymethyltrimethoxysilane, n-Hexadecyloxymethyltrimethoxysilane Examples of suitable compounds include methyltrimethoxysilane, n-heptadecyloxymethyltrimethoxysilane, n-octadecyloxymethyltrimethoxysilane, n-eicosyloxymethyltrimethoxysilane, and compounds in which the trimethoxysilyl groups are substituted with dimethylmethoxysilyl groups, dimethylethoxysilyl groups, methyldimethoxysilyl groups, methyldiethoxysilyl groups, triethoxysilyl groups, dimethylisopropoxysilyl groups, methyldiisopropoxysilyl groups, triisopropoxysilyl groups, etc. Among these, preferred are methoxymethyltrimethoxysilane, ethoxymethyltrimethoxysilane, n-propyloxymethyltrimethoxysilane, isopropyloxymethyltrimethoxysilane, n-butyloxymethyltrimethoxysilane, and isobutyloxymethyltrimethoxysilane.

[0096] In the silane coupling agent (B), the silane coupling agent in which Y is mercapto group can be exemplified as mercaptomethyldimethylmethoxysilane, mercaptomethyldimethylethoxysilane, mercaptomethyldimethylisopropoxysilane, mercaptomethylmethyldimethoxysilane, mercaptomethylmethyldiethoxysilane, mercaptomethylmethyldiisopropoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, mercaptomethyltriisopropoxysilane.Among these, mercaptomethyldimethylmethoxysilane, mercaptomethylmethyldimethoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane are preferred.

[0097] In the silane coupling agent (B), the silane coupling agent in which Y is an isocyanate group can be exemplified by 1-isocyanatemethyldimethylmethoxysilane, 1-isocyanatemethyldimethylethoxysilane, 1-isocyanatemethyldimethylisopropoxysilane, (1-isocyanatemethyl)methyldimethoxysilane, (1-isocyanatemethyl)methyldiethoxysilane, (1-isocyanatemethyl)methyldiisopropoxysilane, 1-isocyanatemethyltrimethoxysilane, 1-isocyanatemethyltriethoxysilane, 1-isocyanatemethyltriisopropoxysilane.Among these, 1-isocyanatemethyldimethylmethoxysilane, (1-isocyanatemethyl)methyldimethoxysilane, 1-isocyanatemethyltrimethoxysilane, 1-isocyanatemethyltriethoxysilane are preferred.

[0098] When the monomer (a2) and / or the mercapto compound (d) are used in producing the polymer (A), the silane coupling agent (B) may be the same as or different from the monomer (a2) and / or the mercapto compound (d).

[0099] <Properties of silane coupling agent (B)> The molecular weight of the silane coupling agent (B) has a lower limit of preferably 80 or more, more preferably 100 or more, and even more preferably 120 or more, and an upper limit of less than 1,000, preferably 750 or less, and more preferably 500 or less.

[0100] <Silane coupling agent (B) content> The composition of the present invention may contain one or more silane coupling agents (B).

[0101] The composition of the present invention contains a total of preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, and even more preferably 1 to 10 parts by mass of the silane coupling agent (B) per 100 parts by mass of the polymer (A). When the content of the silane coupling agent (B) is within the above range, a curable composition having excellent storage stability and excellent adhesiveness even after long-term storage can be obtained.

[0102] [Aminosilane compound (C)] The composition of the present invention preferably contains an aminosilane compound (C) in addition to the polymer (A) and the silane coupling agent (B).

[0103] The aminosilane compound (C) functions as a curing catalyst and a dehydrating agent in the composition of the present invention.

[0104] The aminosilane compound (C) has a group represented by the following formula (3).

[0105] Formula (3):R 4 2-N-(CH2) n -SiR 1 3 [In formula (3), n is an integer of 1 to 6; R 1 is the same as formula (1); R 4 are each independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a group in which at least one hydrogen atom of the hydrocarbon group has been substituted with a group selected from the group consisting of an unsubstituted amino group, a substituted amino group, and an alkoxysilyl group. Examples of the aminosilane compound (C) represented by formula (3) include N-(2-aminoethyl)aminomethyltrimethoxysilane, N-(2-aminoethyl)-2-aminoethyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, aminomethyltrimethoxysilane, 2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, aminomethyltriethoxysilane, 2-aminoethyltriethoxysilane, 3-aminopropyltriethoxysilane, N-[2-( N,N-dimethylamino)ethyl]aminomethyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropylmethyldimethoxysilane, N-[2-(N-vinylbenzylamino)ethyl]-3-aminopropyltrimethoxysilane, bis[3-(trimethoxysilyl)propyl]amine, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, and N-[3-(trimethoxysilyl)propyl]-1-butanamine.

[0106] Among the aminosilane compounds (C), it is preferable to use an aminosilane compound represented by the following formula (3-1) from the viewpoint of improving the tack-free time of the composition of the present invention.

[0107] Formula (3-1):R 4' -NH-(CH2) n' -SiR 1' 3 In formula (3-1), n' is an integer of 1 to 3; R 1' is an alkoxy group having 1 to 6 carbon atoms; R 4 is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group in which at least one hydrogen atom of the hydrocarbon group has been substituted with at least one group selected from the group consisting of an unsubstituted amino group, a substituted amino group, and an alkoxysilyl group.

[0108] The aminosilane compound (C) can be used alone or in combination of two or more.

[0109] The composition of the present invention contains preferably 0.05 to 10 parts by mass, more preferably 0.1 to 8 parts by mass, and even more preferably 0.5 to 5 parts by mass of the aminosilane compound (C) in total, relative to 100 parts by mass of the polymer (A). When the content of the aminosilane compound (C) is within the above range, a curable composition having excellent storage stability and excellent adhesiveness even after long-term storage can be obtained.

[0110] [Other ingredients] In addition to the polymer (A), the composition of the present invention may contain, as necessary, one or more other components such as a polymer (D) having a polyether skeleton, a plasticizer, a filler, silica, a pigment, an antioxidant, a dehydrating agent, a silane coupling agent having an amino group, a curing catalyst, a tackifying resin, a dispersant, a rheology control agent, an antifoaming agent, or an adhesion promoter.

[0111] <Polymer (D)> The composition of the present invention may contain, if necessary, a polymer having a polyether skeleton in addition to the polymer (A). The polymer (D) preferably has a reactive silicon group, and particularly preferably has a group represented by the above formula (1).

[0112] The polymer (D) has a polyether skeleton as the main chain skeleton. The polyether skeleton is preferably a polyoxyalkylene skeleton, such as a polyoxyethylene skeleton, a polyoxypropylene skeleton, a polyoxybutylene skeleton, a polyoxytetramethylene skeleton, a polyoxyethylene-polyoxypropylene skeleton, or a polyoxypropylene-polyoxybutylene skeleton, with a polyoxypropylene skeleton being preferred. The polyoxyalkylene skeleton may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units. The repeating unit here is an oxyalkylene unit. The polymer (D) may have a urethane skeleton between the polyether skeletons.

[0113] The number average molecular weight (Mn) of the polymer (D) is preferably 10,000 to 50,000. If the number average molecular weight (Mn) satisfies such conditions, it is preferable in terms of compatibility with the polymer (A), handleability of the curable composition, and mechanical properties. The number average molecular weight (Mn) is measured by a GPC method.

[0114] Details of the GPC measurement conditions will be described in the Examples section below.

[0115] By using the polymer (D) together with the polymer (A), a curable composition having excellent mechanical properties can be obtained.

[0116] When polymer (D) is used, the group represented by formula (1) in polymer (A) and the group represented by formula (1) in polymer (D) may be the same or different.

[0117] In one embodiment, the polymer (D) preferably has a group represented by formula (1) at the molecular chain terminal of the polymer, and more preferably has a group represented by formula (1) at the molecular chain terminal of a polyether polymer.

[0118] The polymer (D) may be, for example, a polyether polymer having a terminal hydroxyl group and an OCN-CH2-SiR 1 The compound (e-1) (R 1 is synonymous with the same symbol in formula (1)) can be obtained by reacting with an isocyanate group.

[0119] The polymer (D) can also be prepared by obtaining a polyether polymer having an isocyanate group at its terminal from a polyether polymer, and then reacting the terminal isocyanate group of the polymer with R 4 -CH2-SiR 1 3(R 1 is the same as the same symbol described in formula (1), 4The polyether polymer having a terminal isocyanate group can also be obtained by reacting an amino group, an alkylamino group, an (aminoalkyl)amino group, or an (N,N-dialkylaminoalkyl)amino group with an amino group as the terminal isocyanate group. A polyether polymer having a terminal isocyanate group can be obtained, for example, by a urethane reaction between a polyether polymer having a terminal hydroxyl group and a diisocyanate compound. Such a polyether polymer has a urethane skeleton between the polyether skeletons.

[0120] The polymer (D) can also be obtained by obtaining a polyether polymer having an amino group at its terminal from a polyether polymer, and then reacting the terminal amino group of the polymer with the isocyanate group of the compound (e-1).

[0121] Examples of the diisocyanate compound include: Aliphatic diisocyanates having 4 to 30 carbon atoms, such as ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and 2,2,4-trimethyl-1,6-hexamethylene diisocyanate; Alicyclic diisocyanates having 7 to 30 carbon atoms, such as isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylylene diisocyanate; Examples thereof include aromatic diisocyanates having 8 to 30 carbon atoms, such as phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, and diphenylpropane diisocyanate.

[0122] The composition of the present invention may contain one or more polymers (D).

[0123] The content of polymer (D) in the composition of the present invention is preferably 10 to 900 parts by mass, more preferably 20 to 800 parts by mass, per 100 parts by mass of polymer (A). Such an embodiment is preferred from the viewpoint of obtaining a cured product having excellent mechanical properties.

[0124] <Plasticizer> The composition of the present invention may further contain a plasticizer. The use of a plasticizer can improve the flexibility and extensibility of the cured product formed from the curable composition.

[0125] Examples of the plasticizer include phthalate esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, diisodecyl phthalate, butyl benzyl phthalate, and diisononyl phthalate; non-phthalate esters such as 1,2-cyclohexanedicarboxylic acid diisononyl ester and trioctyl trimellitate; aliphatic carboxylic acid esters such as dioctyl adipate, diisodecyl succinate, dibutyl sebacate, and butyl oleate; alcohol esters such as diethylene glycol dibenzoate, triethylene glycol dibenzoate, and pentaerythritol ester; phosphate esters such as trioctyl phosphate and tricresyl phosphate; epoxidized soybean oil, dioctyl 4,5-epoxyhexahydrophthalate, and epoxy esters. Examples of polymer plasticizers include epoxy plasticizers such as benzyl cystearate; chlorinated paraffin; hydrocarbons such as normal paraffin and isoparaffin; alkylsulfonic acid phenyl esters such as alkane (C=10 to 21)sulfonic acid phenyl ester; polyethylene glycol and its derivatives, polypropylene glycol and its derivatives, for example, polyethers in which the hydroxyl groups of polyethylene glycol or polypropylene glycol are blocked with alkyl ethers, polystyrene oligomers such as poly-α-methylstyrene and polystyrene, oligomers such as polybutadiene, butadiene-acrylonitrile copolymer, polychloroprene, polyisoprene, polybutene, hydrogenated polybutene, and epoxidized polybutadiene, and (meth)acrylic polymers other than polymer (A).

[0126] One or more plasticizers can be used.

[0127] In one embodiment, the content of the plasticizer in the composition of the present invention is preferably 10 to 400 parts by mass, more preferably 50 to 300 parts by mass, per 100 parts by mass of the polymer component, from the viewpoints of the coatability of the curable composition and the weather resistance of the cured product.

[0128] <Filler> The compositions of the present invention may further contain a filler.

[0129] Examples of fillers include calcium carbonate such as heavy calcium carbonate, light calcium carbonate, colloidal calcium carbonate, semi-colloidal calcium carbonate, light calcium carbonate, and calcium carbonate obtained by surface-treating the surface of these calcium carbonates with a fatty acid or a resin acid-based organic substance; carbon black; magnesium carbonate; diatomaceous earth; calcined clay; clay; talc; titanium oxide; bentonite; ferric oxide; zinc oxide; activated zinc oxide; aluminum hydroxide; inorganic hollow bodies such as shirasu balloons, perlite, glass balloons, fly ash balloons, alumina balloons, zirconia balloons, and carbon balloons; phenolic resin balloons, epoxy resin balloons, etc. Examples of suitable fillers include organic resin hollow bodies (plastic balloons) such as silicon dioxide resin balloons, urea resin balloons, polyvinylidene chloride resin balloons, polyvinylidene chloride-(meth)acrylic resin balloons, polystyrene balloons, polymethacrylate balloons, polyvinyl alcohol balloons, styrene-(meth)acrylic resin balloons, and polyacrylonitrile balloons; powdery fillers such as resin beads, wood flour, pulp, cotton chips, mica, walnut flour, rice flour, graphite, fine aluminum powder, and flint powder; and fibrous fillers such as glass fiber, glass filament, carbon fiber, Kevlar fiber, and polyethylene fiber. Among these, calcium carbonate surface-treated with a fatty acid or the like is preferred from the viewpoint of dispersibility, and shirasu balloons, glass balloons, polystyrene balloons, and acrylic resin balloons are preferred from the viewpoint of reducing specific gravity and providing heat insulation.

[0130] The filler may be used alone or in combination of two or more kinds.

[0131] The content of the filler in the composition of the present invention is preferably 0.1 to 1,000 parts by mass, more preferably 0.2 to 500 parts by mass, based on 100 parts by mass of the polymer (A). In the present invention, a curable composition having excellent dispersibility of the filler can be obtained.

[0132] <Silica> The composition of the present invention may further contain silica. By using silica, the coatability of the curable composition is improved, and a cured product having excellent weather resistance and elongation can be obtained.

[0133] Examples of silica include fumed silica, and examples of silica include hydrophobic silica and hydrophilic silica, with hydrophobic silica being preferred.

[0134] One or more types of silica can be used.

[0135] In one embodiment, the content of silica in the composition of the present invention is preferably 1 to 100 parts by mass, more preferably 3 to 50 parts by mass, based on 100 parts by mass of the polymer (A).

[0136] <Pigments> The composition of the present invention may further contain a pigment.

[0137] Examples of pigments include inorganic pigments such as iron oxide, chromium oxide, titanium oxide, and cobalt aluminate, and organic pigments such as phthalocyanine blue and phthalocyanine green. The use of pigments is preferred from the viewpoint of improving color matching and weather resistance.

[0138] One or more pigments can be used.

[0139] In one embodiment, the content of the pigment in the composition of the present invention is preferably 1 to 200 parts by mass, more preferably 3 to 100 parts by mass, based on 100 parts by mass of the polymer (A).

[0140] <Anti-aging agent> The composition of the present invention may further contain an anti-aging agent such as an ultraviolet absorber, a light stabilizer, or an antioxidant.

[0141] As ultraviolet absorber, for example, benzotriazole-based ultraviolet absorber, benzophenone-based ultraviolet absorber can be enumerated, and benzotriazole-based ultraviolet absorber is preferred.As benzotriazole-based ultraviolet absorber, for example, 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole, 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(2H-benzotriazole-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, the reaction product of methyl 3-(3-(2H-benzotriazole-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate and polyethylene glycol, 2-(2H-benzotriazole-2-yl)-p-cresol can be enumerated.

[0142] Examples of the light stabilizer include hindered amine-based light stabilizers. Examples of the hindered amine-based light stabilizers include bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine).

[0143] Examples of the antioxidant include hindered phenol-based antioxidants, monophenol-based antioxidants, bisphenol-based antioxidants, polyphenol-based antioxidants, and phosphorus-based antioxidants.

[0144] One or more antioxidants can be used.

[0145] In one embodiment, the content of the antioxidant in the composition of the present invention is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the polymer (A).

[0146] <Dehydrating agent> In order to further improve the storage stability, the composition of the present invention may contain a dehydrating agent in an amount that does not adversely affect the curing property or flexibility.

[0147] Examples of dehydrating agents include hydrolyzable organosilicon compounds such as methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, and vinyltrimethoxysilane; alkyl orthoformates such as methyl orthoformate and ethyl orthoformate; alkyl orthoacetates such as methyl orthoacetate and ethyl orthoacetate; and isocyanate compounds such as p-toluenesulfonyl isocyanate.

[0148] In one embodiment, the content of the dehydrating agent in the composition of the present invention is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, based on 100 parts by mass of the polymer component, from the viewpoints of the storage stability and curability of the curable composition. The polymer component may contain a polymer (D) in addition to the polymer (A).

[0149] <Tackifying resin> The composition of the present invention may further contain a tackifying resin.

[0150] A cured product containing a tackifier resin has appropriate tackiness, and a pressure-sensitive adhesive layer with excellent shear adhesive strength can be obtained.

[0151] Examples of tackifying resins include rosin-based tackifying resins such as rosin ester-based resins, terpene-based tackifying resins such as terpene phenol-based resins, styrene-based tackifying resins, and alicyclic saturated hydrocarbon resins.

[0152] Rosin ester resins are resins obtained by esterifying rosin resins with alcohols. Examples of rosin resins include rosin resins, disproportionated rosin resins, and hydrogenated rosin resins, each of which contains a resin acid such as abietic acid as the main component, as well as dimers of resin acids such as abietic acid (polymerized rosin resins). Examples of alcohols include polyhydric alcohols such as ethylene glycol, glycerin, and pentaerythritol.

[0153] A resin obtained by esterifying a rosin resin is a rosin ester resin, a resin obtained by esterifying a disproportionated rosin resin is a disproportionated rosin ester resin, a resin obtained by esterifying a hydrogenated rosin resin is a hydrogenated rosin ester resin, and a resin obtained by esterifying a polymerized rosin resin is a polymerized rosin ester resin.

[0154] The terpene phenol resin is a resin obtained by polymerizing terpene in the presence of phenol.

[0155] Examples of disproportionated rosin ester resins include Superester A75 (10 or less), Superester A100 (10 or less), Superester A115 (20 or less), and Superester A125 (20 or less). Examples of polymerized rosin ester resins include Pencel D-125 (10-16), Pencel D-135 (10-16), and Pencel D-160 (10-16). These products are manufactured by Arakawa Chemical Industries, Ltd., and the numbers in parentheses indicate acid values ​​(mgKOH / g).

[0156] Examples of terpene-based tackifying resins include YS Polystar T30 (1 or less), YS Polystar T80 (1 or less), YS Polystar T130 (1 or less), Clearon 100 (1 or less), and Clearon 110 (1 or less). These products are manufactured by Yasuhara Chemical, and the numbers in parentheses are acid values ​​(mgKOH / g).

[0157] Examples of styrene-based tackifying resins include FMR-0150 (0.1 or less), FTR-6100 (0.1 or less), FTR-6110 (0.1 or less), FTR-6125 (0.1 or less), FTR-7100 (0.1 or less), FTR-8120 (0.1 or less), FTR-0100 (0.1 or less), FTR-2120 (0.1 or less), and FTR-2140 (0.1 or less). These products are manufactured by Mitsui Chemicals, and the values ​​in parentheses indicate the acid value (mgKOH / g). Another example is SX-100 (1 or less) manufactured by Yasuhara Chemical.

[0158] Examples of alicyclic saturated hydrocarbon resins include Alcon P-90, Alcon P-100, Alcon P-115, Alcon P-125, Alcon M-90, Alcon M-100, Alcon M-115, and Alcon M-135. These products are manufactured by Arakawa Chemical Industries, Ltd.

[0159] The tackifying resins can be used alone or in combination of two or more.

[0160] Among these, from the viewpoint of the storage stability of the curable composition, a tackifier resin having an acid value of 1 mgKOH / g or less is preferred, and an acid value of 0.1 mgKOH / g or less is particularly preferred. By using a tackifier resin having an acid value of 0.1 mgKOH / g or less, a curable composition having particularly excellent storage stability can be obtained. The acid value refers to the number of milligrams of potassium hydroxide required to neutralize 1 g of tackifier resin, and can be measured according to JIS K0070.

[0161] The composition of the present invention contains the tackifier resin in an amount of preferably 1 to 500 parts by mass, more preferably 5 to 300 parts by mass, per 100 parts by mass of the polymer (A). In such an embodiment, the pressure-sensitive adhesive layer has appropriate tackiness and excellent adhesive strength to various adherends.

[0162] <Rheology control agent> The composition of the present invention may further contain a rheology control agent. The rheology control agent can improve the smoothness of the film surface. As the rheology control agent, acrylic, urea, urethane, amide, polyester, layered inorganic compound, and the like can be used. Among these, polyester-based rheology control agents, such as "BYK R606 (polyhydroxycarboxylic acid ester)" manufactured by BYK Japan, are preferred.

[0163] The composition of the present invention contains the rheology control agent in an amount of preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, per 100 parts by mass of the polymer (A). In this embodiment, a curable composition having excellent thixotropy and pseudoplasticity can be obtained.

[0164] [Uses of curable compositions and cured products] The composition of the present invention contains a polymer (A) and a salt compound (B) composed of an acid and a base that satisfy a predetermined pKa, and therefore can be cured under a desired thermal environment, and has excellent storage stability and mechanical properties.

[0165] Furthermore, because the composition of the present invention has good crosslinkability, it can be used in applications where it is cured by crosslinking, or in applications where the elasticity of the cured product is utilized, etc. It is thought that in the composition, moisture present in the atmosphere or in the adherend to which the curable composition is applied causes, for example, hydrolysis of the group represented by formula (1) in polymer (A), and, when polymer (D) is used, the group represented by formula (1) in polymer (D), to form silanol groups, which then undergo dehydration condensation with each other to form siloxane bonds, thereby curing to form a cured product.

[0166] The composition of the present invention or a two-component curable composition obtained by mixing and stirring is suitable for use as a sealant, adhesive, hot melt adhesive, paint, or the like in construction and building material applications, automotive applications, and the like. Other examples include coating agents for covering the surfaces of inorganic materials (e.g., cement, mortar, metal, and glass), sheet-forming compositions (examples of sheets: breathable sheets, protective sheets, water-shielding sheets, vibration-damping sheets, transfer sheets, light-modulating sheets, antistatic sheets, conductive sheets, protective sheets, sound-insulating sheets, light-blocking sheets, decorative sheets, marking sheets, and flame-retardant sheets), film-forming compositions (examples of films: marking films, protective films, ink-fixing films, and laminate films), foam-forming compositions (examples of foams: rigid foams, flexible foams, semi-rigid foams, and flame-retardant foams), compositions for forming vibration-damping materials, sound-insulating materials, sound-proofing materials, sound-absorbing materials, artificial leather, artificial skin, synthetic leather, various industrial parts, daily necessities, and molded toiletry products, paint vehicles, primer resins, and various binders (e.g., ink binders, binders for magnetic recording media, binders for casting, binders for fired bodies, and binders for glass fiber sizing materials).

[0167] The cured product of the present invention can be obtained from the composition of the present invention or the two-component curable composition. The curing conditions are not particularly limited, but curing can be favorably promoted by applying the composition of the present invention to a support and leaving it for a predetermined time in an environment of, for example, -20 to 120°C and 10 to 95% RH, preferably 20 to 90°C and 30 to 85% RH. [Example]

[0168] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the following descriptions of the examples and comparative examples, "parts" means "parts by mass" unless otherwise specified.

[0169] [Evaluation method for polymers, etc.] The methods for evaluating the various physical properties of the polymers and the like are described below.

[0170] <Number average molecular weight (Mn) and weight average molecular weight (Mw)> The number average molecular weight (Mn) and weight average molecular weight (Mw) of a polymer or the like were analyzed by gel permeation chromatography (GPC) and calculated in terms of polystyrene under the following conditions.

[0171] Equipment: GPC-8220 (Tosoh) Column: G7000HXL / 7.8mmID x 1 GMHXL / 7.8mmID x 2 + G2500HXL / 7.8mm ID x 1 Medium: Tetrahydrofuran ·Flow rate: 1.0mL / min ·Concentration: 1.5mg / ml ·Injection volume: 300μL Column temperature: 40℃ <Glass transition temperature (Tg)> The glass transition temperature (Tg) of each polymer was measured by differential scanning calorimetry (DSC).

[0172] Equipment: DSC7000X (Hitachi High-Tech Science) Temperature condition: -100℃ to 30℃ at 10℃ / min Sample container: Aluminum open cell Sample size: 5 mg <Silicon element content> The silicon content of each polymer was measured by adding 7 mL of mixed acid containing hydrogen fluoride to 0.2 g of the polymer, wet ashing using a microwave decomposition device (Anthol Japan), adding ultrapure water to the ashed sample to make a constant volume of 50 mL, and then using an inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0173] Equipment: ICPE-9000 (Shimadzu Corporation) High frequency power: 1.20kW Plasma gas: 10.00 L / min Auxiliary gas: 0.60L / min Carrier gas: 0.70 L / min Observation direction: Axial direction [Manufacturing Example 1] A stainless steel flask equipped with a stirrer, nitrogen gas inlet, thermometer, and reflux condenser was charged with 74 parts n-butyl acrylate, 25 parts 2-ethylhexyl acrylate, and 1 part acryloxymethyltrimethoxysilane. After nitrogen substitution, the mixture was heated to 70°C. Next, while maintaining the contents of the flask at 75°C, 0.9 parts 3-mercaptopropyltrimethoxysilane was added, followed by 0.05 parts 2,2'-azobisisobutyronitrile (AIBN) to initiate the reaction. Three hours after the start of the reaction, 0.05 parts AIBN was added. Six hours after the start of the reaction, volatile components were distilled off under reduced pressure at 110°C for 3 hours to obtain (meth)acrylic polymer (A-1). The silicon content of polymer (A-1) was 1,820 ppm, Mn was 21,000, Mw was 54,000, and Tg was -64°C.

[0174] [Example 1] 100 parts of the (meth)acrylic polymer (A-1), 170 parts of 1,2-cyclohexanedicarboxylic acid diisononyl ester "Hexamoll DINCH" (manufactured by BASF) as a plasticizer, 3 parts of polyhydroxycarboxylic acid ester "BYK R606" (manufactured by BYK) as a thixotropic agent, 10 parts of fumed silica "HDK H18" (manufactured by Wacker Asahi Kasei Co., Ltd.), and 350 parts of heavy calcium carbonate "Whiten 305" (manufactured by Toyo Fine Chemical Co., Ltd.) were mixed in a planetary centrifugal mixer (ARE-310, manufactured by Thinky Co., Ltd.) at a rotational speed of 2,000 rpm for 3 minutes. Next, 4 parts of acryloxymethyltrimethoxysilane "X-12-1169MS" (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 206) as the silane coupling agent (B) and 1 part of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane "KBM-603" (manufactured by Shin-Etsu Chemical Co., Ltd., molecular weight 222) were mixed in an ARE-310 at a rotation speed of 2,000 rpm for 1 minute to obtain a curable composition.

[0175] The resulting curable composition was subjected to various evaluations.

[0176] [Examples 2 to 10, Comparative Examples 1 to 6] Curable compositions were obtained and various evaluations were carried out in the same manner as in Example 1, except that the blending compositions were changed as shown in Tables 1-1 and 1-2. The evaluation methods will be described later.

[0177] The meanings of the notations for each component in Tables 1-1 and 1-2 are as follows:

[0178] X-12-1169MS: Acryloxymethyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 206) X-12-1303MS: methacryloxymethyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 220) X-12-1312MS: Methoxymethyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 166) X-12-1307: Mercaptomethyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 168) KBM-1003: Vinyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 148) KBM-5013: Acryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 234) KBM-6103: N-2-(aminoethyl)-3-aminomethyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 194) Isocyanate methyltrimethoxysilane (molecular weight: 177) KBM-603: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., molecular weight: 222) [Method for evaluating curable compositions] The methods for evaluating the various physical properties of the curable composition are described below.

[0179] <Tuck-free time> The curable compositions obtained in the examples and comparative examples were coated onto a Teflon (registered trademark) sheet using a doctor blade so that the thickness of the cured layer was 2 mm. After starting curing under conditions of 23°C / 50% RH, the time until adhesion of a stainless steel spatula to the composition (cured product) was no longer observed when the spatula was brought into contact with the composition was measured.

[0180] <Stress at break, elongation> The curable compositions obtained in the Examples and Comparative Examples were coated onto a Teflon (registered trademark) sheet using a doctor blade to form a cured layer 2 mm thick, and then aged for 7 days at 23°C / 50% RH. The resulting cured products were then punched out into JIS No. 3 dumbbell-shaped samples. Tensile tests were performed on the resulting samples in accordance with JIS K6251:2010 (Vulcanized rubber and thermoplastic rubber - Determination of tensile properties) at a pulling rate of 200 mm / min at 23°C, and the stress at break and elongation were measured.

[0181] <Shear adhesive strength> The curable compositions obtained in the examples and comparative examples were applied to two aluminum (A1050, 1 mm thick) test pieces according to JIS-K6850:1999 (Testing method for tensile shear bond strength between adhesives and rigid adherends), left to stand for 2 minutes, and then laminated together so that the thickness of the curable composition layer was 0.2 mm. After aging for 7 days under conditions of 23°C / 50% RH, the shear adhesive strength was measured using a universal tensile tester AG-X (Shimadzu Corporation) according to JIS-K6850:1999 at a tensile speed of 50 mm / min and 23°C.

[0182] <Gel fraction> The curable compositions obtained in the Examples and Comparative Examples were coated onto a Teflon (registered trademark) sheet using a doctor blade to form a cured layer 2 mm thick, and then aged for 7 days at 23°C / 50% RH. The resulting cured product was then weighed in a 0.2 g dry mass into a sample bottle, and 40 g of ethyl acetate was added to the sample bottle and allowed to stand at 23°C for 1 day. After filtering through a 200-mesh stainless steel wire mesh made of SUS, the residue on the wire mesh was dried at 90°C for 2 hours. The mass of the resulting residue was weighed, and the gel fraction was calculated using the following formula:

[0183] Gel fraction (%) = (weighing value of residue after drying) ÷ (weighing value of hardened product after curing) × 100 <Shear adhesive strength after storage stability test> The curable compositions obtained in the examples and comparative examples were filled into paper cartridges (330 mL capacity) and left to stand for one month in a 60°C environment as a storage stability test. Thereafter, the shear adhesive strength was measured using the same method as above. The shear adhesive strength of the cured product after the storage stability test (left to stand for one month in a 60°C environment) was divided by the shear adhesive strength of the cured product before the storage stability test (aged for 7 days under conditions of 23°C / 50% RH) to calculate the rate of change in shear adhesive strength [%].

[0184] [Table 1-1]

[0185] [Table 1-2]

Claims

1. a (meth)acrylic polymer (A) having a group represented by formula (1), having a number average molecular weight (Mn) of 1,000 or more, and containing 500 ppm or more of silicon element; A curable composition containing a silane coupling agent (B) represented by formula (2) and having a molecular weight of less than 1,000, A curable composition, wherein the (meth)acrylic polymer (A) has a structural unit derived from a monomer (a2) represented by formula (a2-1): Formula (1): -X-CH 2 -SiR 1 3 [In formula (1), R 1 are each independently an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a hydroxyl group, and R 1 at least one of the groups is the alkoxy group or the hydroxyl group; X is —O—, —COO—, —S—, —N(R 2 )-,-CH(OH)-CH 2 —O—, —O—CO—NH—, or —N(R 2 )-CO-N(R 3 )-, and R 2 and R 3 is a hydrogen atom, a hydrocarbon group, or a halogenated hydrocarbon group, and R 2 and R 3 may be the same or different. Formula (2): Y-CH 2 -SiR 1 3 [In formula (2), R 1 has the same meaning as in formula (1); and Y is a (meth)acryloyl group, an alkoxy group having 1 to 20 carbon atoms, a mercapto group, or an isocyanate group. 【Chemical 1】 [In formula (a2-1), R a represents a hydrogen atom or a methyl group, and R 1 has the same meaning as R 1 in formula (1)]

2. The curable composition according to claim 1, wherein the (B) is contained in an amount of 0.1 to 20 parts by mass per 100 parts by mass of the (meth)acrylic polymer (A).

3. The curable composition according to claim 1, wherein the (meth)acrylic polymer (A) has a group represented by the formula (1) at least at a terminal thereof.

4. 2. The curable composition according to claim 1, wherein the (meth)acrylic polymer (A) has a glass transition temperature (Tg) of −20° C. or lower.

5. 2. The curable composition according to claim 1, wherein the (meth)acrylic polymer (A) has a number average molecular weight of 1,000 to 100,000.

6. The curable composition according to claim 1, comprising 0.05 to 10 parts by mass of an aminosilane compound (C) represented by the following formula (3) relative to 100 parts by mass of the (meth)acrylic polymer (A): Formula (3): R 4 2 -N-(CH 2 ) n -SiR 1 3 [In formula (3), n is an integer of 1 to 6; R 1 is the same as in formula (1); R 4 are each independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a group in which at least one hydrogen atom of the hydrocarbon group has been substituted with a group selected from the group consisting of an unsubstituted amino group, a substituted amino group, and an alkoxysilyl group.

7. A cured product obtained from the curable composition according to any one of claims 1 to 6.

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