Curable composition

Abstract

The present invention contains an organic polymer (A) that has a reactive silicon group, a silane compound (B) that has a molecular weight of 1,500 or less, and a curing catalyst (C). The organic polymer (A) contains a (meth)acrylic acid ester polymer (A1). The silane compound (B) is represented by (R2)3-bX2 bSi-R3-Si(R2)3-bX2 b. R2 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and X2 represents a hydroxyl group or a hydrolyzable group. b is 1, 2, or 3. R3 represents a divalent hydrocarbon group having 1 to 50 carbon atoms.

Description

curable composition

[0001] The present invention relates to a curable composition comprising an organic polymer having reactive silicon groups.

[0002] Organic polymers having a silicon-containing group (hereinafter referred to as a "reactive silicon group") that has a hydroxyl group or a hydrolyzable group on the silicon atom and can form a siloxane bond are known as moisture-reactive polymers, and are contained in many industrial products such as adhesives, sealants, coating materials, paints, and pressure-sensitive adhesives, and are used in a wide range of fields.

[0003] Known polymer skeletons of such reactive silicon group-containing polymers include polyoxyalkylene polymers, saturated hydrocarbon polymers, and (meth)acrylic acid ester copolymers.

[0004] It is known that by blending a low-molecular-weight silane compound (a so-called silane coupling agent) having a reactive silicon group and a reactive group such as an amino group or a vinyl group with a curable composition containing an organic polymer having such a reactive silicon group, the adhesiveness to various adherends and storage stability can be improved (see, for example, Patent Document 1).

[0005] Furthermore, Patent Document 2 describes a method for increasing the elasticity of a moisture-cured elastomer by reacting a polymer having a reactive silicon group with a monosilane compound represented by a specific formula.

[0006] Japanese Patent Laid-Open No. 10-152584 Japanese Patent Laid-Open No. 2005-139452

[0007] It is known that (meth)acrylic acid ester polymers having reactive silicon groups can form cured products that are excellent in weather resistance, water resistance, and the like.

[0008] When a monomer composition that increases the glass transition temperature is used as the monomer composition that constitutes the polymer, a cured product with high strength can be obtained. However, when a monomer composition with a high glass transition temperature is used, the viscosity of the polymer before curing increases, which is disadvantageous in that the handleability of the curable composition decreases.

[0009] To reduce the viscosity before curing, it is possible to use a monomer composition with a low glass transition temperature or to add an additive such as a plasticizer, but this would significantly reduce the strength of the cured product, making it difficult to simultaneously reduce the viscosity before curing and improve the strength after curing.

[0010] In view of the above-mentioned current situation, an object of the present invention is to provide a curable composition that contains an organic polymer having a reactive silicon group and that can achieve both a reduced viscosity before curing and an improved strength after curing.

[0011] In response to the above-mentioned problems, the present inventors discovered that by using at least a (meth)acrylic acid ester polymer as an organic polymer having a reactive silicon group and blending a low-molecular-weight silane compound having at least two reactive silicon groups per molecule, it is possible to achieve both a reduction in viscosity before curing and an improvement in strength after curing, and thus arrived at the present invention.

[0012] That is, the present invention provides a compound represented by the general formula (1): —Si(R １ ) ３－ａ X １ ａ (1) (wherein, R １ Each of X independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. １ each independently represents a hydroxyl group or a hydrolyzable group; and a is 1, 2, or 3. A curable composition comprising an organic polymer (A) having a reactive silicon group represented by the following formula (R): ２ ) ３－ｂ X ２ ｂ Si-R ３ -Si(R ２ ) ３－ｂ X ２ ｂ (2) (wherein, R ２ Each of X independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group.２ each independently represents a hydroxyl group or a hydrolyzable group; b is 1, 2, or 3. ３ represents a divalent hydrocarbon group having 1 to 50 carbon atoms. The divalent hydrocarbon group is —C(═X ３ )-R ５ -NH-, -OC(=X ３ )-R ５ -NH-, -NH-R ５ -C (=X ３ )-R ５ -NH- or -C(=X ３ )-R ５ -NH-R ５ -C (=X ３ )-. ５ represents a direct bond or a divalent hydrocarbon group having 1 to 3 carbon atoms. ３ represents an oxygen atom or a sulfur atom. ３ The divalent hydrocarbon group is —Si(R ２ ) ３－ｂ X ２ ｂ The present invention also relates to a curable composition, which is represented by the following formula: wherein R is an integer of 1 to 3 and R is an integer of 1 to 3. The present invention also relates to a cured product obtained by curing the curable composition.

[0013] According to the present invention, it is possible to provide a curable composition that contains an organic polymer having a reactive silicon group and that can achieve both a reduced viscosity before curing and an improved strength after curing.

[0014] An embodiment of the present invention will be described below. <<Reactive Silicon Group-Containing Organic Polymer (A)>> The curable composition according to the present disclosure contains a reactive silicon group-containing organic polymer (A) (hereinafter also referred to as organic polymer (A)). The term "organic polymer" refers to a polymer whose main chain skeleton is an organic main chain skeleton. Polymers having an inorganic main chain skeleton, such as polysiloxane, are excluded from the term "organic polymer." Specific examples of organic main chain skeletons will be described later.

[0015] <Reactive Silicon Group> The reactive silicon group contained in the organic polymer (A) is represented by the following general formula (1): —Si(R １ ) ３－ａ X１ ａ (1)

[0016] In general formula (1), R １ R each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms. １ The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 1 to 4. The hydrocarbon group may be an unsubstituted hydrocarbon group or a hydrocarbon group having a substituent.

[0017] R １ The hydrocarbon group may have a hetero-containing group as a substituent. The hetero-containing group is a group containing a hetero atom. Here, atoms other than carbon and hydrogen atoms are considered to be hetero atoms.

[0018] Suitable examples of heteroatoms include N, O, S, P, Si, and halogen atoms. In the hetero-containing group, the total number of carbon atoms and heteroatoms is preferably 1 to 10, more preferably 1 to 6, and still more preferably 1 to 4.

[0019] Suitable examples of hetero-containing groups include a hydroxyl group; a mercapto group; halogen atoms such as Cl, Br, I, and F; a nitro group; a cyano group; alkoxy groups such as a methoxy group, an ethoxy group, an n-propyloxy group, and an isopropyloxy group; alkylthio groups such as a methylthio group, an ethylthio group, an n-propylthio group, and an isopropylthio group; acyl groups such as an acetyl group, a propionyl group, and a butanoyl group; acyloxy groups such as an acetyloxy group, a propionyloxy group, and a butanoyloxy group; substituted or unsubstituted amino groups such as an amino group, a methylamino group, an ethylamino group, a dimethylamino group, and a diethylamino group; substituted or unsubstituted aminocarbonyl groups such as an aminocarbonyl group, a methylaminocarbonyl group, an ethylaminocarbonyl group, a dimethylaminocarbonyl group, and a diethylaminocarbonyl group; and a cyano group.

[0020] R １ is a hydrocarbon group having a hetero-containing group, R １The total number of carbon atoms and hetero atoms in is preferably 2 to 30, more preferably 2 to 18, even more preferably 2 to 10, and particularly preferably 2 to 6.

[0021] R １ Specific examples of the hydrocarbon group having 1 to 20 carbon atoms as the alkyl group include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethyl-n-hexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group; and a vinyl group. alkenyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; aryl groups such as phenyl, naphthalen-1-yl, naphthalen-2-yl, o-phenylphenyl, m-phenylphenyl, and p-phenylphenyl groups; and aralkyl groups such as benzyl, phenethyl, naphthalen-1-ylmethyl, and naphthalen-2-ylmethyl groups.

[0022] These hydrocarbon groups substituted with the hetero-containing groups described above are also included in R １ It is preferable as.

[0023] R １ Suitable examples of R include alkyl groups such as methyl and ethyl groups; alkyl groups having a hetero-containing group such as chloromethyl and methoxymethyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl groups; and aralkyl groups such as benzyl groups. １ As the alkyl group, a methyl group, a methoxymethyl group, and a chloromethyl group are preferred, a methyl group and a methoxymethyl group are more preferred, and a methyl group is even more preferred.

[0024] X １each independently represents a hydroxyl group or a hydrolyzable group. １ Specific examples of the reactive silicon group include a hydroxyl group, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, an alkoxy group is more preferred because it is mildly hydrolyzable and easy to handle. Generally, the fewer the carbon atoms in an alkoxy group, the higher the reactivity. That is, the reactivity decreases in the order of a methoxy group, an ethoxy group, and a propoxy group. By utilizing this property, the specific structure of the reactive silicon group can be appropriately determined depending on the production method and application of the organic polymer (A).

[0025] a is 1, 2, or 3. a is preferably 2 or 3, and particularly preferably 3, because this results in better strength of the cured product.

[0026] <<Reactive Silicon Group-Containing (Meth)acrylic Acid Ester Polymer (A1)>> The reactive silicon group-containing organic polymer (A) contained in the curable composition according to the present disclosure contains at least a reactive silicon group-containing (meth)acrylic acid ester polymer (A1). By using the (meth)acrylic acid ester polymer (A1) in combination with a silane compound (B) described below, the strength of the cured product can be improved.

[0027] The reactive silicon group contained in the (meth)acrylic acid ester polymer (A1) can be represented by the above-mentioned general formula (1).Specific examples of the reactive silicon group contained in (A1) include a dimethoxysilyl group, a trimethoxysilyl group, a diethoxysilyl group, a triethoxysilyl group, a triisopropoxysilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, and a diisopropoxymethylsilyl group.From the viewpoint of the curability of the curable composition, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a trimethoxysilyl group, and a triethoxysilyl group are preferred, and a dimethoxymethylsilyl group or a trimethoxysilyl group is particularly preferred.

[0028] The average number of reactive silicon groups contained in one molecule of the (meth)acrylic acid ester polymer (A1) is preferably in the range of 0.05 to 10, more preferably in the range of 0.5 to 5, and particularly preferably in the range of 1 to 3, from the viewpoint of performance such as adhesiveness and tensile properties of the cured product.

[0029] The position of the reactive silicon group contained in the (meth)acrylic acid ester polymer (A1) is not particularly limited, and may be on the side chain, the main chain terminal, and / or a region near the terminal of the polymer. When designing a rubber material excellent in flexibility and elongation, it is preferable that the reactive silicon group be at least at the main chain terminal of the polymer.

[0030] The reactive silicon group-containing (meth)acrylic acid ester polymer (A1) is a polymer having a structural unit derived from a (meth)acrylic monomer and a reactive silicon group. The polymer (A1) can be obtained, for example, by polymerizing a monomer mixture containing a (meth)acrylic monomer and a vinyl monomer having a reactive silicon group. In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0031] The amount of the (meth)acrylic monomer used is preferably in the range of 10 to 100% by weight, more preferably in the range of 30 to 100% by weight, and even more preferably in the range of 50 to 100% by weight, based on all constituent monomers of the reactive silicon group-containing (meth)acrylic acid ester polymer (A1).

[0032] The (meth)acrylic monomer is a monomer having a (meth)acryloyl group in the molecule, and a representative example thereof is a (meth)acrylic acid alkyl ester. Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, and n-butyl (meth)acrylate. -octyl, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate and isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, (meth)acrylate Henicosyl (meth)acrylate, Behenyl (meth)acrylate, Tetracosyl (meth)acrylate, Hexacosyl (meth)acrylate, Octacosyl (meth)acrylate, Triacontyl (meth)acrylate, Dotriacontyl (meth)acrylate, Tetratriacontyl (meth)acrylate, Hexatriacontyl (meth)acrylate, Octatriacontyl (meth)acrylate, Tetracontyl (meth)acrylate, Isodecyl (meth)acrylate, Isoundecyl (meth)acrylate, Isolauryl (meth)acrylate acrylate, isotridecyl (meth)acrylate, isotetradecyl (meth)acrylate, isopentadecyl (meth)acrylate, isohexadecyl (meth)acrylate, isoheptadecyl (meth)acrylate, isostearyl (meth)acrylate, isononadecyl (meth)acrylate, isoeicosyl (meth)acrylate, isoheneicosyl (meth)acrylate, isobehenyl (meth)acrylate, isotetracosyl (meth)acrylate, isohexacosyl (meth)acrylate, isooctacosyl (meth)acrylate,Examples include alkyl (meth)acrylate esters having a linear or branched aliphatic alkyl group or an alicyclic alkyl group, such as isotriacontyl (meth)acrylate, isodotriacontyl (meth)acrylate, isotetratriacontyl (meth)acrylate, isohexatriacontyl (meth)acrylate, isooctatriacontyl (meth)acrylate, and isotetracontyl (meth)acrylate. One or more of these may be used. Among these, alkyl (meth)acrylate esters having a linear or branched aliphatic alkyl group having 1 to 8 carbon atoms are preferred from the viewpoint of the mechanical properties of the cured product.

[0033] Examples of monomers other than alkyl (meth)acrylates include functional group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, and ethylene oxide adducts of (meth)acrylic acid; aromatic (meth)acrylate esters such as phenyl (meth)acrylate, toluyl (meth)acrylate, and benzyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, and glycidyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as 2-ethoxyethyl (meth)acrylate and 3-methoxypropyl (meth)acrylate; trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluorobutylethyl (meth)acrylate; fluorine-containing (meth)acrylic acid esters such as perfluoroethylmethyl, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, perfluoroethylene, perfluoropropylene, and vinylidene fluoride; aromatic monomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and its salts; maleic anhydride; unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and monoalkyl esters thereof; alkyl and dialkyl esters; maleimide compounds such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, phenylmaleimide, and cyclohexylmaleimide; nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; amide group-containing vinyl monomers such as acrylamide and methacrylamide; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; alkenes such as ethylene and propylene;Examples include, but are not limited to, conjugated dienes such as butadiene and isoprene; vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol. One or more of these may be used.

[0034] In the production of the (meth)acrylic acid ester polymer (A1), a vinyl monomer having a reactive silicon group can be used to introduce reactive silicon into the polymer. The monomer may be a (meth)acrylic acid ester having a reactive silicon group. Use of a vinyl monomer having a reactive silicon group allows the reactive silicon group to be randomly introduced into the side chain of the polymer (A1).

[0035] Examples of the vinyl monomer having reactive silicon group include reactive silicon group-containing vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, etc.; reactive silicon group-containing (meth)acrylic acid esters such as trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, dimethylmethoxysilylpropyl (meth)acrylate, methyldimethoxysilylpropyl (meth)acrylate, trimethoxysilylmethyl (meth)acrylate, methyldimethoxysilylmethyl (meth)acrylate; reactive silicon group-containing vinyl ethers such as trimethoxysilylpropyl vinyl ether; reactive silicon group-containing vinyl esters such as vinyl trimethoxysilylundecanoate, etc. These monomers may be used alone or in combination of two or more.

[0036] In the production of the (meth)acrylic acid ester-based polymer (A1), a chain transfer agent may be used to control the molecular weight and molecular weight distribution of the polymer. The chain transfer agent may not have a reactive silicon group, or may have a reactive silicon group. When a chain transfer agent having a reactive silicon group is used, the reactive silicon group can be introduced into the main chain terminal of the polymer (A1).

[0037] Specific examples of the chain transfer agent are not particularly limited, but include, for example, 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropyltrimethoxysilane, (mercaptomethyl)dimethoxymethylsilane, (mercaptomethyl)trimethoxysilane, n-dodecyl mercaptan, tert-dodecyl mercaptan, lauryl mercaptan, etc. These chain transfer agents may be used alone or in combination of two or more.

[0038] The number average molecular weight (Mn) of the reactive silicon group-containing (meth)acrylic acid ester polymer (A1), as measured by gel permeation chromatography (hereinafter also referred to as "GPC") in terms of polystyrene, is preferably in the range of 2,000 to 80,000. When Mn is 2,000 or more, the strength of the resulting cured product tends to be good, and when Mn is 80,000 or less, the workability of the curable composition tends to be good. The upper limit of Mn is more preferably 60,000 or less, even more preferably 30,000 or less, and particularly preferably 10,000 or less. It may also be 5,000 or less.

[0039] The viscosity of the reactive silicon group-containing (meth)acrylic acid ester polymer (A1) at 25° C. is preferably in the range of 0.5 to 1,000 Pa s, more preferably in the range of 5 to 800 Pa s, and even more preferably in the range of 20 to 500 Pa s. A viscosity of 0.5 Pa s or more is preferred because sagging when applied to a vertical surface is easily suppressed, while a viscosity of 1,000 Pa s or less tends to improve the workability of the curable composition.

[0040] The glass transition temperature (Tg) of the (meth)acrylic acid ester polymer (A1) is not particularly limited, but may be, for example, from −100° C. to 100° C., and preferably from −60° C. to 60° C. The higher the glass transition temperature of the (meth)acrylic acid ester polymer (A1), the better the strength of the cured product, and therefore is preferred. Generally, as the Tg of a polymer increases, the viscosity of the curable composition tends to increase. However, according to the present invention, the viscosity of the curable composition can be reduced, so that even a (meth)acrylic acid ester polymer (A1) with a high glass transition temperature can be suitably used. This makes it possible to provide a curable composition that has high strength after curing and a relatively low viscosity before curing.

[0041] The Tg of the (meth)acrylic acid ester polymer (A1) can be adjusted by adjusting the type and composition ratio of the monomers constituting the polymer. Tg can be calculated using the following Fox formula: 1 / (Tg(K))=Σ(Mi / Tgi) (where Mi represents the weight fraction of the monomer i constituting the polymer, and Tgi represents the glass transition temperature (K) of the homopolymer of the monomer i).

[0042] <Method for producing reactive silicon group-containing (meth)acrylic acid ester polymer (A1)> Next, a method for producing the reactive silicon group-containing (meth)acrylic acid ester polymer (A1) will be described. The reactive silicon group-containing (meth)acrylic acid ester polymer (A1) can be produced by conventional radical polymerization. For example, any of solution polymerization, bulk polymerization, dispersion polymerization, high-temperature continuous polymerization, etc. may be used, or a living radical polymerization method may be utilized. The reaction process may be any of batch, semi-batch, and continuous polymerization methods.

[0043] High-temperature continuous polymerization methods may be performed according to known methods disclosed in, for example, Japanese Patent Application Laid-Open Nos. 57-502171, 59-6207, and 60-215007. For example, a pressurizable reactor is filled with a solvent, set to a predetermined temperature under pressure, and then a monomer mixture consisting of each monomer and, if necessary, a polymerization solvent is fed to the reactor at a constant feed rate, and an amount of polymerization liquid corresponding to the amount of monomer mixture fed is withdrawn. A polymerization initiator may also be blended into the monomer mixture as needed. When a polymerization initiator is blended, the blending amount is preferably 0.001 to 2 parts by weight per 100 parts by weight of the monomer mixture. The pressure depends on the reaction temperature and the boiling points of the monomer mixture and solvent used, and may be any pressure that does not affect the reaction but can maintain the reaction temperature. The residence time of the monomer mixture is preferably 1 to 60 minutes, more preferably 2 to 40 minutes.

[0044] Generally, when reactive silicon groups are uniformly introduced into a polymer, the curability of a curable composition containing the polymer and the physical properties of the resulting cured product, such as weather resistance, become good. In this regard, when living radical polymerization is used, a (meth)acrylic acid ester polymer having a relatively narrow molecular weight distribution can be obtained, and the number of reactive silicon groups in one polymer molecular chain and the position of the reactive silicon group (side chain, terminal, or near the terminal) can be freely controlled.

[0045] When a living radical polymerization method is used, the type thereof is not particularly limited, and various polymerization methods can be used, such as reversible addition-fragmentation chain transfer polymerization (RAFT method), nitroxy radical method (NMP method), atom transfer radical polymerization (ATRP method), polymerization method using an organotellurium compound (TERP method), polymerization method using an organoantimony compound (SBRP method), polymerization method using an organobismuth compound (BIRP method), iodine transfer polymerization, reversible transfer catalyst polymerization (RTCP method) using an organic catalyst, and reversible coordination-mediated polymerization (RCMP method). Among these, the RAFT method, the NMP method, and the ATRP method are preferred from the viewpoints of polymerization controllability and ease of implementation.

[0046] In the RAFT method, controlled polymerization proceeds via a reversible chain transfer reaction in the presence of a specific polymerization control agent (RAFT agent) and a general free radical polymerization initiator. As the RAFT agent, various known RAFT agents such as dithioester compounds, xanthate compounds, trithiocarbonate compounds, and dithiocarbamate compounds can be used.

[0047] The RAFT agent may be monofunctional, having only one active site, or may be bifunctional or higher functional. The amount of the RAFT agent used can be adjusted appropriately depending on the types of monomer and RAFT agent used, etc.

[0048] As the polymerization initiator used in polymerization by the RAFT method, known radical polymerization initiators such as azo compounds, organic peroxides, and persulfates can be used. However, azo compounds are preferred because they are easy to handle safely and are less likely to cause side reactions during radical polymerization.

[0049] Specific examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], and 2,2'-azobis(N-butyl-2-methylpropionamide).

[0050] The radical polymerization initiators may be used alone or in combination of two or more.

[0051] The proportion of the radical polymerization initiator used is not particularly limited, but from the viewpoint of obtaining a polymer with a narrower molecular weight distribution, the amount of radical polymerization initiator used per 1 mol of the RAFT agent is preferably 0.5 mol or less, more preferably 0.2 mol or less. Furthermore, from the viewpoint of stably carrying out the polymerization reaction, the lower limit of the amount of radical polymerization initiator used per 1 mol of the RAFT agent is preferably 0.01 mol or more, more preferably 0.05 mol or more.

[0052] The reaction temperature during the polymerization reaction by the RAFT method is preferably 40°C or higher and 100°C or lower, more preferably 45°C or higher and 90°C or lower, and even more preferably 50°C or higher and 80°C or lower.

[0053] In the NMP method, a specific alkoxyamine compound having a nitroxide is used as a living radical polymerization initiator, and polymerization proceeds via the nitroxide radical derived from the alkoxyamine compound. Although there are no particular limitations on the type of nitroxide compound, it is preferable to use a nitroxide compound represented by the following general formula (4) from the viewpoint of polymerization controllability when polymerizing a (meth)acrylic acid alkyl ester:

[0054]

[0055] In general formula (4), R ８ is an alkyl group having 1 to 2 carbon atoms or a hydrogen atom, and R ９ is an alkyl group or a nitrile group having 1 to 2 carbon atoms, and R １０ Ha-(CH ２ ) ｍ -, m is 0 to 2, and R １１ , R １２ is an alkyl group having 1 to 4 carbon atoms.

[0056] The nitroxide compound represented by the general formula (4) undergoes primary dissociation upon heating at approximately 70 to 80°C, and undergoes an addition reaction with a vinyl monomer. In this case, a polyfunctional polymerization precursor can be obtained by adding the nitroxide compound to a vinyl monomer having two or more vinyl groups. The polymerization precursor is then subjected to secondary dissociation under heating, allowing the vinyl monomer to undergo living polymerization.

[0057] The amount of the nitroxide compound used is adjusted appropriately depending on the types of the monomer and nitroxide compound used.

[0058] When a high molecular weight (meth)acrylic acid ester polymer is produced by the NMP method, polymerization may be carried out by adding 0.001 to 0.2 mol of a nitroxide radical represented by the following general formula (5) to 1 mol of the nitroxide compound represented by the general formula (4):

[0059]

[0060] In general formula (5), R １１ , R １２ is an alkyl group having 1 to 4 carbon atoms. By adding 0.001 mol or more of the nitroxide radical represented by the general formula (5), the time required for the nitroxide radical concentration to reach a steady state is shortened. This makes it possible to more precisely control the polymerization, and a polymer with a narrower molecular weight distribution can be obtained. On the other hand, if the amount of the nitroxide radical added is too large, the polymerization may not proceed. The amount of the nitroxide radical added per mol of the nitroxide compound is more preferably in the range of 0.01 to 0.5 mol, and even more preferably in the range of 0.05 to 0.2 mol.

[0061] The reaction temperature in the NMP method is preferably 50°C or higher and 140°C or lower, more preferably 60°C or higher and 130°C or lower, even more preferably 70°C or higher and 120°C or lower, and particularly preferably 80°C or higher and 120°C or lower.

[0062] The RTCP method uses organic molecules with chain transfer ability as catalysts. The central elements of the catalyst include phosphorus, nitrogen, oxygen, and carbon. The catalyst is a compound with iodine bound to the central element, such as N-succinimide (NIS), in which iodine is bound to nitrogen. The RCMP method uses organic molecules such as tertiary amines that coordinate with the iodine of a protecting group. The organic molecules coordinate with the iodine of dormant species and extract iodine from the dormant species (acting as an activator), reversibly generating a growing radical and a complex of iodine and the catalyst. Neutral molecules such as tertiary amines, or organic salts such as quaternary ammonium salts and quaternary phosphonium salts, are used as catalysts. For example, this method is disclosed in Proceedings of the Polymer Research Journal, Vol. 72, No. 5 (2015). In addition, methods for producing (meth)acrylic acid ester-based polymers having reactive silicon groups using this polymerization method are disclosed in JP-A-2022-075627 and JP-A-2022-075628.

[0063] Among living radical polymerization methods, "atom transfer radical polymerization" (so-called ATRP), which polymerizes (meth)acrylic acid ester monomers using an organic halide or a sulfonyl halide compound as an initiator and a transition metal complex as a catalyst, is more preferred as a method for producing a (meth)acrylic acid ester polymer having a specific functional group, since, in addition to the characteristics of the living radical polymerization described above, the monomer has a terminal halogen atom, which is relatively advantageous for functional group conversion reactions, and has a large degree of freedom in the design of initiators and catalysts. This ATRP method is described, for example, in Matyjaszewski et al., Journal of the American Chemical Society (J. Am. Chem. Soc.), 1995, Vol. 117, p. 5614.

[0064] In the ATRP method, a polymerization reaction is generally carried out using an organic halide as an initiator and a transition metal complex as a catalyst. The organic halide used as the initiator may be monofunctional or bifunctional or higher. Furthermore, preferred types of halogens are bromides and chlorides. For example, Japanese Patent Laid-Open Publication No. 9-272714 discloses a production method using atom transfer radical polymerization, but the present invention is not limited thereto.

[0065] As a method for introducing a reactive silicon group into the main chain of the (meth)acrylic acid ester-based polymer (A1), a known method may be adopted. As described above, a (meth)acrylic acid ester-based polymer having a reactive silicon group in its side chain can be easily obtained by copolymerizing a (meth)acrylic monomer with a vinyl-based monomer having a reactive silicon group.

[0066] Furthermore, by using a halogen compound having a reactive silicon group (or a functional group that can be converted into a reactive silicon group) as an initiator for the ATRP method, it is possible to obtain a polymer having a reactive silicon group (or a functional group that can be converted into a reactive silicon group) at the polymer terminal on the polymerization initiation side.

[0067] In the ATRP method, a halogen group is generally present at the polymer growth terminal, and this halogen group can be converted into a functional group having a reactive silicon group using a conventionally known method.

[0068] In this way, by making full use of methods such as introducing reactive silicon groups into the terminals or copolymerizing vinyl monomers having reactive silicon groups, the position of the reactive silicon group can be freely controlled depending on the purpose, such as at the main chain terminal, near the terminal, or on the side chain of the polymer.

[0069] Furthermore, the Activators Regenerated by Electron Transfer (ARGET) method, a synthetic method that improves on the ATRP method, has also been reported (Macromolecules. 2006, 39, 39). This method uses a reducing agent to reduce highly oxidized transition metal complexes, which cause delays or terminations in polymerization, and thereby allows the polymerization reaction to proceed rapidly to a high conversion rate even under low catalyst conditions with a small amount of transition metal complex. This ARGET method can also be used to produce polymer (A1).

[0070] The curable composition according to the present disclosure may contain, as the reactive silicon group-containing organic polymer (A), only the reactive silicon group-containing (meth)acrylic acid ester polymer (A1), or may further contain, in addition to the polymer (A1), a reactive silicon group-containing organic polymer other than the polymer (A1).

[0071] The reactive silicon group-containing organic polymer other than the (meth)acrylic acid ester polymer (A1) is not particularly limited, and examples thereof include: hydrocarbon polymers such as polyoxyalkylene polymers; ethylene-propylene copolymers, polyisobutylene, copolymers of isobutylene and isoprene, and hydrogenated polyolefin polymers obtained by hydrogenating these polyolefin polymers; polyester polymers obtained by condensation of dibasic acids such as adipic acid with glycols, or by ring-opening polymerization of lactones; polysulfide polymers; polyamide polymers; polycarbonate polymers; diallyl phthalate polymers; etc. Among these, only one type may be used, or two types may be used in combination.

[0072] Among these, saturated hydrocarbon polymers or polyoxyalkylene polymers are preferred because they have a relatively low glass transition temperature. In particular, it is preferred to further contain a polyoxyalkylene polymer (A2) because it has good compatibility with the (meth)acrylic acid ester polymer (A1) and can reduce the viscosity of the curable composition. The polyoxyalkylene polymer (A2) having a reactive silicon group will be described in detail below.

[0073] <<Reactive Silicon Group-Containing Polyoxyalkylene Polymer (A2)>> The reactive silicon group contained in the polyoxyalkylene polymer (A2) can be represented by the above-mentioned general formula (1). The reactive silicon group contained in the (meth)acrylic acid ester polymer (A1) and the reactive silicon group contained in the polyoxyalkylene polymer (A2) may be the same silicon group or different silicon groups.

[0074] Specific examples of reactive silicon groups contained in the polyoxyalkylene polymer (A2) include, but are not limited to, trimethoxysilyl, triethoxysilyl, tris(2-propenyloxy)silyl, triacetoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethoxyethylsilyl, (chloromethyl)dimethoxysilyl, (chloromethyl)diethoxysilyl, (methoxymethyl)dimethoxysilyl, (methoxymethyl)diethoxysilyl, (N,N-diethylaminomethyl)dimethoxysilyl, and (N,N-diethylaminomethyl)diethoxysilyl groups. Among these, dimethoxymethylsilyl, trimethoxysilyl, triethoxysilyl, and (methoxymethyl)dimethoxysilyl groups are preferred because they give cured products with good mechanical properties. From the viewpoint of activity, trimethoxysilyl group, (chloromethyl)dimethoxysilyl group, and (methoxymethyl)dimethoxysilyl group are more preferred, and trimethoxysilyl group is particularly preferred because it improves curability.

[0075] The number of reactive silicon groups in one molecule of the polyoxyalkylene polymer (A2) is preferably 1 to 7 on average, more preferably 1.1 to 3.4, and particularly preferably 1.2 to 2.6, from the viewpoint of the balance between flexibility and recovery.

[0076] In order to obtain a good rubber-like cured product, the reactive silicon groups of the polyoxyalkylene polymer (A2) are preferably present at the terminals of the main chain. In order to show good curability and easily exhibit rubber elastic behavior, the number of reactive silicon groups per terminal of the polymer (A2) is preferably 0.5 or more, more preferably 0.6 or more, even more preferably 0.7 or more, and particularly preferably 0.8 or more, on average.

[0077] The main chain structure of the polyoxyalkylene polymer (A2) may be linear or branched.

[0078] The main chain of the polyoxyalkylene polymer (A2) is —R １３ -O- (wherein, R １３ is a linear or branched alkylene group having 1 to 14 carbon atoms), and R １３ is more preferably a linear or branched alkylene group having 2 to 4 carbon atoms. １３ Specific examples of the repeating unit represented by —O— include —CH ２ O-, -CH ２ CH ２ O-, -CH ２ CH (CH ３ ) O—, —CH ２ C(CH ３ ) (CH ３ ) O—, —CH ２ CH ２ CH ２ CH ２ O-, etc., but -CH ２ CH ２ O-, -CH ２ CH (CH ３ )O— is preferred, and —CH ２ CH (CH ３ ) O- is more preferred.

[0079] In particular, when the curable composition according to the present disclosure is used as a sealant, adhesive, or the like, a polyoxypropylene-based polymer having oxypropylene repeating units in a proportion of preferably 50% by weight or more, more preferably 80% by weight or more of the polymer main chain structure is preferred because it is amorphous and has a relatively low viscosity.

[0080] The polyoxyalkylene polymer (A2) may be a polyoxyalkylene polymer containing other bonds such as a urethane bond, a urea bond, an ester bond, an amide bond, etc. in its main chain structure. However, from the viewpoint of obtaining a curable composition excellent in storage stability and workability, the polyoxyalkylene polymer (A2) is preferably a polyoxyalkylene polymer that does not contain a urethane bond, a urea bond, an ester bond, or an amide bond in its main chain structure.

[0081] The number average molecular weight of the polyoxyalkylene polymer (A2) is not particularly limited, but is preferably 5,000 to 100,000, more preferably 10,000 to 50,000, particularly preferably 12,000 to 40,000, and most preferably 13,000 to 30,000, as calculated in terms of polystyrene by GPC measurement. When the number average molecular weight is within the above range, the amount of reactive silicon groups introduced is appropriate, making it easy to obtain a polyoxyalkylene polymer (A2) with high strength while keeping production costs within an appropriate range.

[0082] The molecular weight distribution (Mw / Mn) of the polyoxyalkylene polymer (A2) is not particularly limited, but is preferably narrow. Specifically, it is preferably 1.6 or less, more preferably 1.4 or less, even more preferably 1.3 or less, and particularly preferably 1.2 or less. A molecular weight distribution within the above range is preferred from the viewpoints of ease of handling, such as workability, and adhesiveness. The molecular weight distribution of the polyoxyalkylene polymer (A2) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

[0083] <Method for producing reactive silicon group-containing polyoxyalkylene polymer (A2)> Next, a method for producing the reactive silicon group-containing polyoxyalkylene polymer (A2) will be described. The reactive silicon group-containing polyoxyalkylene polymer (A2) can be produced by introducing a reactive silicon group into a precursor polymer to which a reactive silicon group can be introduced. Specifically, the reactive silicon group-containing polyoxyalkylene polymer (A2) can be produced by introducing an olefin group into a polyoxyalkylene polymer (d1) having a terminal hydroxyl group by utilizing the reactivity of the hydroxyl group to obtain a precursor polymer having an olefin group, and then reacting the precursor polymer with a reactive silicon group-containing compound reactive with the olefin group to introduce the reactive silicon group.

[0084] (Polymerization) The polymer backbone of the polyoxyalkylene polymer can be formed by polymerizing an epoxy compound with an initiator having a hydroxyl group by a conventionally known method, thereby obtaining a polyoxyalkylene polymer (d1) having a hydroxyl group at its terminal. Although the specific polymerization method is not particularly limited, a polymerization method using a composite metal cyanide complex catalyst such as a zinc hexacyanocobaltate glyme complex is preferred because it can produce a hydroxyl-terminated polymer with a small molecular weight distribution (Mw / Mn).

[0085] The initiator having a hydroxyl group is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, glycerin, pentaerythritol, low-molecular-weight polyoxypropylene glycol, low-molecular-weight polyoxypropylene triol, butanol, allyl alcohol, methanol, ethanol, propanol, butanol, pentanol, hexanol, low-molecular-weight polyoxypropylene monoallyl ether, low-molecular-weight polyoxypropylene monoalkyl ether, etc. When a polymer having three or more main chain ends in one molecule is to be obtained, glycerin, pentaerythritol, low-molecular-weight polyoxypropylene triol, etc. having three or more hydroxyl groups can be used.

[0086] The epoxy compound is not particularly limited, but examples thereof include alkylene oxides such as ethylene oxide and propylene oxide, and glycidyl ethers such as methyl glycidyl ether and butyl glycidyl ether, with propylene oxide being preferred.

[0087] (Reaction with alkali metal salt) When introducing an olefin group into a polyoxyalkylene polymer (d1) having a terminal hydroxyl group, it is preferable to first react an alkali metal salt with the polyoxyalkylene polymer (d1) to convert the terminal hydroxyl group into an alkoxide terminal. Alternatively, a composite metal cyanide complex catalyst can be used instead of the alkali metal salt. In this manner, an alkoxide-terminated polyoxyalkylene polymer (d2) is formed.

[0088] The alkali metal salt is not particularly limited, but examples thereof include sodium hydroxide, sodium alkoxide, potassium hydroxide, potassium alkoxide, lithium hydroxide, lithium alkoxide, cesium hydroxide, and cesium alkoxide. From the viewpoint of ease of handling and solubility, sodium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium hydroxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide are preferred, with sodium methoxide and sodium tert-butoxide being more preferred. From the viewpoint of availability, sodium methoxide is preferred. The alkali metal salt may be subjected to the reaction in a state dissolved in a solvent.

[0089] (Reaction with Electrophile (d3)) The alkoxide-terminated polyoxyalkylene polymer (d2) obtained as described above is reacted with an electrophile (d3) having an olefin group to convert the alkoxide terminal into a structure containing an olefin group, thereby forming a polyoxyalkylene polymer (d4) having an olefin group in the terminal structure.

[0090] The electrophilic agent (d3) having an olefin group is not particularly limited as long as it is a compound that can react with the alkoxide terminal of the polyoxyalkylene polymer (d2) and introduce an olefin group into the polyoxyalkylene polymer, and examples thereof include an organic halide (d3-1) having an olefin group and an epoxy compound (d3-2) having an olefin group.

[0091] The organic halide (d3-1) having an olefin group, which is one embodiment of the electrophilic agent (d3), reacts with the alkoxide terminal through a halogen substitution reaction to form an ether bond, thereby introducing a structure containing an olefin group as a terminal structure of the polyoxyalkylene polymer.

[0092] Specific examples of the organic halide (d3-1) having an olefin group include, but are not limited to, vinyl chloride, allyl chloride, methallyl chloride, vinyl bromide, allyl bromide, methallyl bromide, vinyl iodide, allyl iodide, and methallyl iodide. From the viewpoint of ease of handling, allyl chloride and methallyl chloride are preferred. Furthermore, methallyl chloride, methallyl bromide, and methallyl iodide are preferred because they improve the average ratio of the number of reactive silicon groups to the number of terminals of the polymer skeleton.

[0093] Furthermore, a halogenated hydrocarbon compound having a carbon-carbon triple bond can also be used as the organic halide (d3-1) having an olefin group. The halogenated hydrocarbon compound having a carbon-carbon triple bond is not particularly limited, and examples thereof include propargyl chloride, propargyl bromide, and propargyl iodide. Furthermore, a halogenated hydrocarbon compound having a carbon-carbon double bond may be used simultaneously with the halogenated hydrocarbon compound having a carbon-carbon triple bond.

[0094] An epoxy compound (d3-2) having an olefin group, which is another embodiment of the electrophile (d3), can react with the alkoxide terminal through a ring-opening addition reaction of the epoxy group to form an ether bond, thereby introducing a structure containing an olefin group and a hydroxyl group as a terminal structure of the polyoxyalkylene polymer. In the ring-opening addition reaction, one or more epoxy compounds (d3-2) can be added to one alkoxide terminal by adjusting the amount of epoxy compound (d3-2) used relative to the alkoxide terminal and the reaction conditions.

[0095] Specific examples of the epoxy compound (d3-2) having an olefin group are not particularly limited, but allyl glycidyl ether, methallyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, and butadiene monoxide are preferred in terms of reactivity, and allyl glycidyl ether is particularly preferred.

[0096] As described above, when the alkoxide-terminated polyoxyalkylene polymer (d2) is reacted with the epoxy compound (d3-2) having an olefin group, a new alkoxide is generated by ring-opening of the epoxy group. Therefore, after the reaction with the epoxy compound (d3-2), the polymer can be reacted with the organic halide (d3-1) having an olefin group.

[0097] (Introduction of Reactive Silicon Groups) The polyoxyalkylene polymer (d4) having an olefin group in its terminal structure or the polyoxyalkylene polymer (d5) (precursor polymer) having a carbon-carbon triple bond in its terminal structure obtained as described above can be subjected to a hydrosilylation reaction with a hydrosilane compound (d6) having a reactive silicon group, thereby introducing a reactive silicon group into the polymer. This produces a reactive silicon group-containing polyoxyalkylene polymer (A2). The hydrosilylation reaction has the advantages of being simple to carry out, easy to adjust the amount of reactive silicon group introduced, and stable physical properties of the resulting polymer.

[0098] Specific examples of the hydrosilane compound (d6) having a reactive silicon group include halosilanes such as trichlorosilane, dichloromethylsilane, chlorodimethylsilane, dichlorophenylsilane, (chloromethyl)dichlorosilane, (dichloromethyl)dichlorosilane, bis(chloromethyl)chlorosilane, (methoxymethyl)dichlorosilane, (dimethoxymethyl)dichlorosilane, and bis(methoxymethyl)chlorosilane; trimethoxysilane, triethoxysilane, dimethoxymethylsilane, diethoxymethylsilane, and the like. Tylsilane, dimethoxyphenylsilane, ethyldimethoxysilane, methoxydimethylsilane, ethoxydimethylsilane, (chloromethyl)methylmethoxysilane, (chloromethyl)dimethoxysilane, (chloromethyl)diethoxysilane, bis(chloromethyl)methoxysilane, (methoxymethyl)methylmethoxysilane, (methoxymethyl)dimethoxysilane, bis(methoxymethyl)methoxysilane, (methoxymethyl)diethoxysilane, (ethoxymethyl)diethoxysilane, (3,3,3-triphenylsilane) (chloromethyl)dimethoxysilane, (N,N-diethylaminomethyl)dimethoxysilane, (N,N-diethylaminomethyl)diethoxysilane, [(chloromethyl)dimethoxysilyloxy]dimethylsilane, [(chloromethyl)diethoxysilyloxy]dimethylsilane, [(methoxymethyl)dimethoxysilyloxy]dimethylsilane, [(methoxymethyl)diethoxysilyloxy]dimethylsilane, [(diethylaminomethyl)dimethoxysilyloxy]dimethylsilane, [(3,3,3-trichloromethyl)dimethoxysilyloxy]dimethylsilane alkoxysilanes such as [(fluoropropyl)dimethoxysilyloxy]dimethylsilane; acyloxysilanes such as diacetoxymethylsilane and diacetoxyphenylsilane; ketoximate silanes such as bis(dimethylketoximate)methylsilane and bis(cyclohexylketoximate)methylsilane; and isopropenyloxysilanes (deacetone type) such as triisopropenyloxysilane, (chloromethyl)diisopropenyloxysilane, and (methoxymethyl)diisopropenyloxysilane.

[0099] The hydrosilylation reaction is preferably carried out in the presence of a hydrosilylation catalyst to promote the reaction. Known hydrosilylation catalysts include metals such as cobalt, nickel, iridium, platinum, palladium, rhodium, and ruthenium, as well as complexes thereof, and these can be used. Specific examples of the hydrosilylation catalyst include platinum supported on a support such as alumina, silica, or carbon black; chloroplatinic acid; chloroplatinic acid complexes composed of chloroplatinic acid and alcohols, aldehydes, ketones, or the like; platinum-olefin complexes [e.g., Pt(CH ２ =CH ２ ) ２ (PPh ３ ), Pt(CH ２ =CH ２ ) ２ Cl ２ ]; platinum-vinylsiloxane complexes [e.g., Pt{(vinyl)Me ２ SiOSiMe ２ (vinyl)}, Pt{Me(vinyl)SiO} ４ platinum-phosphine complexes [e.g., Ph(PPh ３ ) ４ , Pt(PBu ３ ) ４ ]; platinum-phosphite complexes [e.g., Pt{P(OPh) ３} ４ In terms of reaction efficiency, platinum catalysts such as chloroplatinic acid and platinum vinylsiloxane complexes are preferred.

[0100] As another method for producing the reactive silicon group-containing polyoxyalkylene polymer (A2), a method can also be applied in which a compound (d7) having a reactive silicon group and an isocyanate group in one molecule is allowed to react with a polyoxyalkylene polymer (d1) (precursor polymer) having a terminal hydroxyl group to form a urethane bond and introduce a reactive silicon group.

[0101] The compound (d7) having a reactive silicon group and an isocyanate group in one molecule is not particularly limited as long as it is a compound having both an isocyanate group capable of undergoing a urethane-forming reaction with a hydroxyl group in the polyoxyalkylene polymer (d1) and a reactive silicon group in one molecule. Specific examples include (3-isocyanatepropyl)trimethoxysilane, (3-isocyanatepropyl)dimethoxymethylsilane, (3-isocyanatepropyl)triethoxysilane, (3-isocyanatepropyl)diethoxymethylsilane, (isocyanatemethyl)trimethoxysilane, (isocyanatemethyl)triethoxysilane, (isocyanatemethyl)dimethoxymethylsilane, and (isocyanatemethyl)diethoxymethylsilane.

[0102] The urethanization reaction may be carried out without using a urethanization catalyst, or may be carried out in the presence of a urethanization catalyst for the purpose of improving the reaction rate or the reaction rate. Examples of such urethanization catalysts include conventionally known urethanization catalysts, such as those listed in "Polyurethanes: Chemistry and Technology," Part I, Table 30, Chapter 4, Saunders and Frisch, Interscience Publishers, New York, 1963. Specific examples include, but are not limited to, basic catalysts such as organotin compounds, bismuth compounds, and organic amines.

[0103] As yet another method for producing the reactive silicon group-containing polyoxyalkylene polymer (A2), a method can also be applied in which an excess of a polyisocyanate compound (d8) is reacted with a polyoxyalkylene polymer (d1) having a terminal hydroxyl group to form a polymer (precursor polymer) having an isocyanate group at its terminal, and then the precursor polymer is reacted with a compound (d9) having a group reactive with an isocyanate group (e.g., an amino group) and a reactive silicon group.

[0104] Examples of the polyisocyanate compound (d8) include aromatic polyisocyanates such as toluene (tolylene) diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; and aliphatic polyisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate.

[0105] Examples of the compound (d9) having a group reactive with an isocyanate group and a reactive silicon group include γ-aminopropyltrimethoxysilane, γ-aminopropyldimethoxymethylsilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyldimethoxymethylsilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-(N-phenyl)aminopropyltrimethoxysilane, γ-(N-phenyl)aminopropyldi Examples thereof include amino group-containing silanes such as methoxymethylsilane, N-ethylaminoisobutyltrimethoxysilane, N-ethylaminoisobutyldimethoxymethylsilane, N-cyclohexylaminomethyltrimethoxysilane, and N-cyclohexylaminomethyldimethoxymethylsilane; hydroxy group-containing silanes such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyldimethoxymethylsilane; and mercapto group-containing silanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyldimethoxymethylsilane.

[0106] As yet another method for producing the reactive silicon group-containing polyoxyalkylene polymer (A2), a method can also be applied in which a polyoxyalkylene polymer (d4) (precursor polymer) having an olefin group in its terminal structure is reacted with a compound (d10) having a reactive silicon group and a mercaptan group in one molecule to form a sulfide bond by addition of the mercaptan group to the olefin group, thereby introducing the reactive silicon group.

[0107] The compound (d10) having a reactive silicon group and a mercaptan group in one molecule is not particularly limited as long as it is a compound having both a mercaptan group capable of addition reaction with an olefin group in the polyoxyalkylene polymer (d4) and a reactive silicon group in one molecule. Specific examples include (3-mercaptopropyl)methyldimethoxysilane, (3-mercaptopropyl)trimethoxysilane, (3-mercaptopropyl)methyldiethoxysilane, (3-mercaptopropyl)triethoxysilane, (mercaptomethyl)methyldimethoxysilane, (mercaptomethyl)trimethoxysilane, (mercaptomethyl)methyldiethoxysilane, and (mercaptomethyl)triethoxysilane.

[0108] The addition reaction of a mercaptan group to an olefin group may be carried out without using a radical initiator, but may be carried out in the presence of a radical initiator in order to improve the reaction rate or the reaction rate. As such a radical initiator, a conventionally known initiator can be used. Specific examples include, but are not limited to, azo-based initiators and peroxide-based initiators.

[0109] Among known radical initiators, catalysts with low activity toward reactive silicon groups are preferred, and from this viewpoint, azo-based initiators such as 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (V-59), and 2,2'-azobis(1-methylcyclohexanecarbonitrile) (V-40) are particularly preferred.

[0110] Methods of blending a (meth)acrylic acid ester polymer (A1) with a polyoxyalkylene polymer (A2) have been proposed in JP-A Nos. 59-122541, 63-112642, 6-172631, and 11-116763. Alternatively, a method of polymerizing a (meth)acrylic acid ester monomer in the presence of a polyoxypropylene polymer having a reactive silicon group can be used. This production method is specifically disclosed in JP-A Nos. 59-78223, 60-228516, and 60-228517.

[0111] In the curable composition according to the present disclosure, the blending ratio of the (meth)acrylic acid ester polymer (A1) to the polyoxyalkylene polymer (A2) is not particularly limited. From the viewpoint of the balance between the improvement in strength by (A1) and the reduction in viscosity by (A2), the weight ratio of (A1):(A2) is preferably 5:95 to 95:5, more preferably 10:90 to 80:20, and particularly preferably 20:80 to 60:40.

[0112] <<Silane Compound (B)>> The curable composition according to the present disclosure contains a low-molecular-weight silane compound (B) having at least two reactive silicon groups per molecule. By incorporating such a silane compound (B), the viscosity of the curable composition can be reduced and the strength of the cured product obtained by curing the composition can be improved.

[0113] The mechanism by which the strength of the cured product is improved by blending the silane compound (B) is not clear, but it is presumed that the silane compound (B) also participates in the polymer network formed by the organic polymer (A) upon curing of the curable composition, thereby increasing the number of crosslinked structures and improving the crosslink density.

[0114] The silane compound (B) is a compound represented by the following general formula (2): (R ２ ) ３－ｂ X ２ ｂ Si-R ３ -Si(R ２ ) ３－ｂ X ２ ｂ (2) In general formula (2), -Si(R ２ ) ３－ｂ X ２ ｂ The reactive silicon group of the silane compound (B) may be the same as or different from the reactive silicon group of the organic polymer (A).

[0115] In general formula (2), R ２R each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. ２ The details of R in the general formula (1) are as follows: １ The details are the same as those in (1), so they will be omitted here.

[0116] X ２ each independently represents a hydroxyl group or a hydrolyzable group. ２ Specific examples of the formula are X in the general formula (1) above. １ In view of the availability of the silane compound (B) and the effect of improving the strength, X ２ is preferably an alkoxy group, more preferably a methoxy group or an ethoxy group, and particularly preferably a methoxy group.

[0117] b is 1, 2, or 3. Since the effect of improving the strength of the cured product is good, b is preferably 2 or 3, and 3 is particularly preferred. -Si(R ２ ) ３－ｂ X ２ ｂ As the reactive silicon group represented by the formula: a trialkoxysilyl group is particularly preferred, and a trimethoxysilyl group is most preferred.

[0118] In general formula (2), R ３ represents a divalent hydrocarbon group having 1 to 50 carbon atoms, which is a group sandwiching two reactive silicon groups. The hydrocarbon group refers to a group consisting only of carbon atoms and hydrogen atoms, but the hydrocarbon group may contain a specific structure described below.

[0119] R ３ The number of carbon atoms in the hydrocarbon group is R ３ The number of carbon atoms is preferably 3 to 30, and more preferably 5 to 20. However, R ３ The number of carbon atoms in the hydrocarbon group does not include the number of carbon atoms contained in the specific structure described below or the number of carbon atoms contained in the reactive silicon group.

[0120] R ３ The hydrocarbon group is -C(=X ３ )-R ５-NH-, -OC(=X ３ )-R ５ -NH-, -NH-R ５ -C (=X ３ )-R ５ -NH- or -C(=X ３ )-R ５ -NH-R ５ -C (=X ３ )- (hereinafter referred to as "specific structure"). The divalent hydrocarbon group does not have to contain the specific structure, but it preferably contains the specific structure because this improves the strength-improving effect. The improvement in strength due to the specific structure is presumed to be due to the formation of hydrogen bonds between ester bonds contained in the main chain skeleton of the (meth)acrylic acid ester polymer (A1) and NH groups in the specific structure, which increases the cohesive strength of the cured product.

[0121] R ３ The hydrocarbon group containing the specific structure means that the specific structure is contained within the hydrocarbon group. That is, atoms at both ends of the specific structure are bonded to the hydrocarbon group. Therefore, it is preferable that the specific structure is not directly bonded to the silicon atom in general formula (2).

[0122] The specific structure is —O—C(═X) from the viewpoint of availability of the silane compound (B) and from the viewpoint of the strength improving effect. ３ )-R ５ -NH- or -NH-R ５ -C (=X ３ )-R ５ —NH— is particularly preferred.

[0123] Also, R ３ The divalent hydrocarbon group may contain only one of the specific structures, or may contain multiple (two or more) of the specific structures. When multiple specific structures are contained, the specific structures may be directly bonded to each other, or the hydrocarbon group may be interposed between them. Furthermore, the specific structures may be bonded to each other to form a cyclic structure (for example, an isocyanurate ring).

[0124] R contained in the specific structure ５represents a direct bond or a divalent hydrocarbon group having 1 to 3 carbon atoms. From the viewpoint of availability of the silane compound (B) and the effect of improving strength, R ５ is preferably a direct bond. ５ is a direct bond, the specific structure is -C(=X ３ )-NH-, -OC(=X ３ )-NH-, -NH-C(=X ３ ) -NH- or -C(=X ３ )-NH-C(=X ３ )- is expressed as

[0125] X contained in the specific structure ３ represents an oxygen atom or a sulfur atom. From the viewpoint of availability of the silane compound (B) and the strength improving effect, X ３ is preferably an oxygen atom. ３ is an oxygen atom, and R ５ is a direct bond, the specific structure is represented by -C(=O)-NH- (amide bond), -O-C(=O)-NH- (urethane bond), -NH-C(=O)-NH- (urea bond), or -C(=O)-NH-C(=O)- (imide bond). Among these, -O-C(=O)-NH- (urethane bond) or -NH-C(=O)-NH- (urea bond) is particularly preferred.

[0126] R ３ The divalent hydrocarbon group is —Si(R ２ ) ３－ｂ X ２ ｂ

[0039] The silane compound (B) may further have a third reactive silicon group represented by the following formula:

[0040] That is, the silane compound (B) may have three reactive silicon groups per molecule. However, from the viewpoint of the physical properties of the cured product, it is preferable that the silane compound (B) has two reactive silicon groups per molecule.

[0127] The silane compound (B) is preferably a silane compound having no amino group. Examples of silane compounds having an amino group include bis(3-trimethoxysilylpropyl)amine and amino group-containing silanes described below.

[0128] Specific examples of the silane compound (B) include, but are not limited to, bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 4-(3-trimethoxysilylpropylcarbamoyloxy)butyl-N-(3-trimethoxysilylpropyl)carbamate, N,N'-bis(3-trimethoxysilylpropyl)urea, and tris[3-(trimethoxysilyl)propyl] isocyanurate.

[0129] From the viewpoint of reducing the viscosity of the curable composition, the molecular weight of the silane compound (B) is preferably 1,500 or less, more preferably 1,000 or less, and even more preferably 700 or less. The lower limit is not particularly limited, but may be, for example, 100 or more or 150 or more.

[0130] The amount of the silane compound (B) can be appropriately set from the viewpoint of the effects of the invention, but is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, particularly preferably 1 to 10 parts by weight, and particularly preferably 2 to 8 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0131] <<Curing Catalyst (C)>> The curable composition according to the present disclosure contains a curing catalyst (C) (also referred to as a silanol condensation catalyst) for hydrolyzing and condensing the reactive silicon groups of the organic polymer (A) to cure the curable composition.

[0132] Examples of the curing catalyst (C) include organotin compounds, metal carboxylates, amine compounds, carboxylic acids, and alkoxy metals.

[0133] Specific examples of organotin compounds include dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin bis(butyl maleate), dibutyltin diacetate, dibutyltin oxide, dibutyltin bis(acetylacetonate), dioctyltin bis(acetylacetonate), dioctyltin dilaurate, dioctyltin distearate, dioctyltin diacetate, dioctyltin oxide, a reaction product of dibutyltin oxide with a silicate compound, a reaction product of dioctyltin oxide with a silicate compound, and a reaction product of dibutyltin oxide with a phthalate ester.

[0134] Specific examples of metal carboxylates include tin carboxylate, bismuth carboxylate, titanium carboxylate, zirconium carboxylate, iron carboxylate, potassium carboxylate, calcium carboxylate, etc. The carboxylic acid group can be a combination of the following carboxylic acids with various metals. Specifically, iron 2-ethylhexanoate (divalent), iron 2-ethylhexanoate (trivalent), titanium 2-ethylhexanoate (tetravalent), vanadium 2-ethylhexanoate (trivalent), calcium 2-ethylhexanoate (divalent), potassium 2-ethylhexanoate (monovalent), barium 2-ethylhexanoate (divalent), manganese 2-ethylhexanoate (divalent), nickel 2-ethylhexanoate (divalent), cobalt 2-ethylhexanoate (divalent), zirconium 2-ethylhexanoate (tetravalent), iron neodecanoate (divalent), iron neodecanoate (trivalent), titanium neodecanoate (tetravalent), vanadium neodecanoate (trivalent), calcium neodecanoate (divalent), potassium neodecanoate (monovalent), barium neodecanoate (divalent), di-ethylhexanoate Examples of suitable oleic acids include zinc (tetravalent), iron oleate (divalent), iron oleate (trivalent), titanium oleate (tetravalent), vanadium oleate (trivalent), calcium oleate (divalent), potassium oleate (monovalent), barium oleate (divalent), manganese oleate (divalent), nickel oleate (divalent), cobalt oleate (divalent), zirconium oleate (tetravalent), iron naphthenate (divalent), iron naphthenate (trivalent), titanium naphthenate (tetravalent), vanadium naphthenate (trivalent), calcium naphthenate (divalent), potassium naphthenate (monovalent), barium naphthenate (divalent), manganese naphthenate (divalent), nickel naphthenate (divalent), cobalt naphthenate (divalent), and zirconium naphthenate (tetravalent).

[0135] Specific examples of the amine compound include amines such as octylamine, 2-ethylhexylamine, laurylamine, and stearylamine; nitrogen-containing heterocyclic compounds such as pyridine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), and 1,5-diazabicyclo[4,3,0]nonene-5 (DBN); guanidines such as guanidine, phenylguanidine, and diphenylguanidine; biguanides such as butylbiguanide, 1-o-tolylbiguanide, and 1-phenylbiguanide; amino group-containing silane coupling agents; and ketimine compounds.

[0136] Specific examples of carboxylic acids include acetic acid, propionic acid, butyric acid, 2-ethylhexanoic acid, lauric acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, and versatic acid.

[0137] Specific examples of alkoxy metals include titanium compounds such as tetrabutyl titanate titanium tetrakis(acetylacetonate) and diisopropoxytitanium bis(ethylacetoacetate), aluminum compounds such as aluminum tris(acetylacetonate) and diisopropoxyaluminum ethylacetoacetate, and zirconium compounds such as zirconium tetrakis(acetylacetonate).

[0138] In addition, a fluorine anion-containing compound, a photoacid generator, or a photobase generator can also be used as the curing catalyst (C).

[0139] Two or more different curing catalysts (C) may be used in combination. The amount of curing catalyst (C) added is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, and particularly preferably 0.01 to 10 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0140] <<Curable Composition>> In addition to the reactive silicon group-containing organic polymer (A), the silane compound (B), and the curing catalyst (C), the curable composition according to the present disclosure may contain additives such as fillers, adhesion promoters, plasticizers, solvents, diluents, anti-sagging agents, antioxidants, light stabilizers, UV absorbers, physical property adjusters, tackifier resins, epoxy group-containing compounds, photocurable substances, oxygen-curable substances, epoxy resins, and other resins. Furthermore, various additives may be added to the curable composition according to the present disclosure as needed for the purpose of adjusting the physical properties of the curable composition or the cured product. Examples of such additives include surface property improvers, foaming agents, curability adjusters, flame retardants, silicates, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, and mildew inhibitors.

[0141] <Filler> The curable composition according to the present disclosure may contain various fillers, such as heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, clay, talc, titanium oxide, fumed silica, precipitated silica, crystalline silica, fused silica, silicic anhydride, hydrated silicic acid, carbon black, ferric oxide, fine aluminum powder, zinc oxide, activated zinc white, PVC powder, PMMA powder, glass fiber, and filament.

[0142] The amount of filler used is preferably 1 to 600 parts by weight, and particularly preferably 10 to 300 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0143] Organic or inorganic balloons may be added to reduce the weight (specific gravity) of the composition. Balloons are hollow spherical fillers, and examples of materials for the balloons include inorganic materials such as glass, shirasu, and silica, and organic materials such as phenolic resin, urea resin, polystyrene, and saran. The amount of balloons used is preferably 0.1 to 100 parts by weight, and particularly preferably 1 to 20 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0144] <Adhesion Imparting Agent> An adhesion imparting agent may be added to the curable composition according to the present disclosure. Examples of the adhesion imparting agent that may be added include a silane coupling agent and a reaction product of a silane coupling agent.

[0145] Specific examples of the silane coupling agent include amino group-containing silanes such as γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and (2-aminoethyl)aminomethyltrimethoxysilane; γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, and γ-isopropyltriethoxysilane; Examples of suitable silanes include isocyanate group-containing silanes such as cyanate propyl methyl dimethoxy silane, α-isocyanate methyl trimethoxy silane, and α-isocyanate methyl dimethoxy methyl silane; mercapto group-containing silanes such as γ-mercapto propyl trimethoxy silane, γ-mercapto propyl triethoxy silane, and γ-mercapto propyl methyl dimethoxy silane; and epoxy group-containing silanes such as γ-glycidoxy propyl trimethoxy silane and β-(3,4-epoxycyclohexyl) ethyl trimethoxy silane.

[0146] Also usable are condensates of various silane coupling agents such as condensates of aminosilane, condensates of aminosilane and other alkoxysilanes, and reaction products of various silane coupling agents such as reaction products of aminosilane and epoxysilane, reaction products of aminosilane and (meth)acrylic group-containing silane, etc. Specific examples include Dynasylan 1146 and Dynasylan 1124 (manufactured by EVONIK).

[0147] The adhesion promoter may be used alone or in combination of two or more kinds. The amount of the silane coupling agent used is preferably 0.1 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0148] <Plasticizer> A plasticizer can be added to the curable composition according to the present disclosure. Specific examples of the plasticizer include phthalate ester compounds such as dibutyl phthalate, diisononyl phthalate (DINP), diheptyl phthalate, di(2-ethylhexyl) phthalate, diisodecyl phthalate (DIDP), and butyl benzyl phthalate; terephthalate ester compounds such as bis(2-ethylhexyl)-1,4-benzenedicarboxylate; 1,2-cyclohexanedicarboxylic acid diisononyl ester (specifically, Hexamoll®, a product under the trade name of Hexamoll®); non-phthalate ester compounds such as dioctyl adipate, dioctyl sebacate, dibutyl sebacate, diisodecyl succinate, and acetyl tributyl citrate; unsaturated fatty acid ester compounds such as butyl oleate and methyl acetylricinoleate; alkylsulfonic acid phenyl esters (specifically, trade name: Mesamoll (manufactured by LANXESS)); phosphate ester compounds; trimellitic acid ester compounds; chlorinated paraffins; hydrocarbon oils such as alkyl diphenyls and partially hydrogenated terphenyls; process oils; and epoxy plasticizers such as epoxidized soybean oil and epoxy benzyl stearate.

[0149] Specific examples of polymer plasticizers include vinyl polymers, polyester plasticizers, polyether polyols such as polyethylene glycol and polypropylene glycol having a number average molecular weight of 500 or more, and polyethers such as derivatives in which the hydroxy groups of these polyether polyols are converted to ester groups, ether groups, etc., polystyrenes, polybutadiene, polybutene, polyisobutylene, butadiene-acrylonitrile, and polychloroprene.

[0150] The amount of plasticizer used is preferably 5 to 150 parts by weight, more preferably 10 to 120 parts by weight, and even more preferably 20 to 100 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A). The plasticizers may be used alone or in combination of two or more.

[0151] <Solvent, Diluent> A solvent or diluent can be added to the curable composition according to the present disclosure. The solvent and diluent are not particularly limited, but aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, alcohols, esters, ketones, ethers, and the like can be used. When using a solvent or diluent, in consideration of the problem of air pollution when the composition is used indoors, the boiling point of the solvent is preferably 150°C or higher, more preferably 200°C or higher, and particularly preferably 250°C or higher. The above solvents or diluents may be used alone or in combination of two or more types.

[0152] <Anti-sagging agent> An anti-sagging agent may be added to the curable composition according to the present disclosure as needed to prevent sagging and improve workability. The anti-sagging agent is not particularly limited, and examples thereof include polyamide waxes; hydrogenated castor oil derivatives; and metal soaps such as calcium stearate, aluminum stearate, and barium stearate. These anti-sagging agents may be used alone or in combination of two or more.

[0153] The amount of the anti-sagging agent used is preferably 0.1 to 20 parts by weight per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0154] <Antioxidant> An antioxidant (antiaging agent) can be used in the curable composition according to the present disclosure. The use of an antioxidant can improve the weather resistance of the cured product. Examples of antioxidants include hindered phenols, monophenols, bisphenols, and polyphenols. Examples include BHT, Irganox 245, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1135, Irganox 1330, Irganox 1520, and SONGNOX 1076. Similarly, hindered amine light stabilizers such as TINUVIN 622LD, TINUVIN 144, and TINUVIN 292; CHIMASSORB 944LD and CHIMASSORB 119FL (all manufactured by BASF); ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-67, ADK STAB LA-63, and ADK STAB LA-68 (all manufactured by ADEKA Corporation); SANOL LS-2626, SANOL LS-1114, and SANOL LS-744 (all manufactured by Sankyo Lifetech Co., Ltd.); and NOCRAC CD (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) can also be used. Other antioxidants that can be used include SONGNOX 4120, NAUGUARD 445, and OKABEST CLX050.

[0155] Specific examples of antioxidants are also described in Japanese Patent Application Laid-Open Nos. 4-283259 and 9-194731.

[0156] The amount of antioxidant used is preferably 0.1 to 10 parts by weight, particularly preferably 0.2 to 5 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0157] <Light Stabilizer> A light stabilizer can be used in the curable composition according to the present disclosure. The use of a light stabilizer can prevent photooxidative degradation of the cured product. Examples of light stabilizers include benzotriazole-based, hindered amine-based, and benzoate-based compounds, with hindered amine-based compounds being particularly preferred.

[0158] Examples of hindered amine light stabilizers include TINUVIN 123, TINUVIN 144, TINUVIN 249, TINUVIN 292, TINUVIN 312, TINUVIN 622LD, TINUVIN 765, TINUVIN 770, TINUVIN 880, TINUVIN 5866, and TINUVIN B97; CHIMASSORB 119FL and CHIMASSORB 944LD (all manufactured by BASF); ADK STAB LA-57, LA-62, LA-63, LA-67, and LA-68 (all manufactured by ADEKA Corporation); SANOL LS-292, LS-2626, LS-765, LS-744, and LS-1114 (all manufactured by Sankyo Lifetech Co., Ltd.); SABOSTAB UV91 and SABOSTAB Examples of light stabilizers include UV119, SONGSORB CS5100, SONGSORB CS622, SONGSORB CS944 (all manufactured by SONGWON), and NOCRAC CD (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.).

[0159] The amount of the light stabilizer used is preferably 0.1 to 10 parts by weight, particularly preferably 0.2 to 5 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0160] <Ultraviolet Absorber> An ultraviolet absorber can be used in the curable composition according to the present disclosure. The use of an ultraviolet absorber can improve the surface weather resistance of the cured product. Examples of ultraviolet absorbers include benzophenone-based, benzotriazole-based, salicylate-based, triazine-based, substituted acrylonitrile-based, and metal chelate-based compounds, with benzotriazole-based compounds being particularly preferred. Examples include TINUVIN 234, TINUVIN 326, TINUVIN 327, TINUVIN 328, TINUVIN 329, TINUVIN 350, TINUVIN 571, TINUVIN 900, TINUVIN 928, TINUVIN 1130, and TINUVIN 1600 (all manufactured by BASF); and SONGSORB 3290 (manufactured by SONGWON). Examples of triazine compounds include TINUVIN 400, TINUVIN 405, TINUVIN 477, and TINUVIN 1577ED (all manufactured by BASF), SONGSORB CS400 and SONGSORB 1577 (manufactured by SONGWON), etc. Examples of benzophenone compounds include SONGSORB 8100 (manufactured by SONGWON).

[0161] The amount of the ultraviolet absorber used is preferably 0.1 to 10 parts by weight, particularly preferably 0.2 to 5 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0162] Addworks IBC760 (manufactured by Clariant) can also be used as a product containing an antioxidant, a light stabilizer, and an ultraviolet absorber.

[0163] <Tackifying Resin> In the present invention, a tackifying resin can be added for the purpose of improving adhesion or adhesion to a substrate, or as otherwise required. There are no particular limitations on the tackifying resin, and any commonly used resin can be used.

[0164] Specific examples include terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene-phenol resins, phenol resins, modified phenol resins, xylene-phenol resins, cyclopentadiene-phenol resins, coumarone-indene resins, rosin resins, rosin ester resins, hydrogenated rosin ester resins, xylene resins, low molecular weight polystyrene resins, styrene copolymer resins, styrene block copolymers and hydrogenated products thereof, petroleum resins (e.g., C5 hydrocarbon resins, C9 hydrocarbon resins, C5C9 hydrocarbon copolymer resins, etc.), hydrogenated petroleum resins, DCPD resins, etc. These may be used alone or in combination of two or more.

[0165] The amount of the tackifier resin used is preferably 2 to 100 parts by weight, more preferably 5 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0166] <Compound containing an epoxy group> A compound containing an epoxy group can be used in the curable composition according to the present disclosure. The use of a compound containing an epoxy group can improve the recovery of the cured product. Examples of compounds containing an epoxy group include epoxidized unsaturated fats and oils, epoxidized unsaturated fatty acid esters, alicyclic epoxy compounds, epichlorohydrin derivatives, and mixtures thereof. Specific examples include epoxidized soybean oil, epoxidized linseed oil, bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS), epoxy octyl stearate, and epoxy butyl stearate. The epoxy compound is preferably used in an amount of 0.5 to 50 parts by weight per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0167] <Photocurable Substance> A photocurable substance can be used in the curable composition according to the present disclosure. When a photocurable substance is used, a film of the photocurable substance is formed on the surface of the cured product, improving the stickiness and weather resistance of the cured product. Many compounds of this type are known, including organic monomers, oligomers, resins, and compositions containing them. Representative examples include unsaturated acrylic compounds, which are monomers or oligomers having one or more acrylic or methacrylic unsaturated groups, or mixtures thereof, polyvinyl cinnamates, and azido resins.

[0168] The amount of the photocurable substance used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0169] <Oxygen-Curable Substance> An oxygen-curable substance can be used in the curable composition according to the present disclosure. Examples of oxygen-curable substances include unsaturated compounds that can react with oxygen in the air, which react with oxygen in the air to form a cured film near the surface of the cured product, preventing surface stickiness and preventing the adhesion of dirt and dust to the surface of the cured product. Specific examples of oxygen-curable substances include drying oils such as tung oil and linseed oil, and various alkyd resins obtained by modifying such compounds; acrylic polymers, epoxy resins, and silicone resins modified with drying oils; and liquid polymers such as 1,2-polybutadiene, 1,4-polybutadiene, and polymers of C5 to C8 dienes obtained by polymerizing or copolymerizing diene compounds such as butadiene, chloroprene, isoprene, and 1,3-pentadiene. These substances may be used alone or in combination of two or more.

[0170] The amount of the oxygen-curable substance used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A). As described in JP-A-3-160053, the oxygen-curable substance is preferably used in combination with a photocurable substance.

[0171] <Epoxy Resin> The curable composition according to the present disclosure can be used in combination with an epoxy resin. Compositions containing an epoxy resin are particularly suitable as adhesives, especially adhesives for exterior wall tiles. Examples of epoxy resins include bisphenol A epoxy resins and novolac epoxy resins.

[0172] The ratio by weight of these epoxy resins to the reactive silicon group-containing organic polymer (A) is preferably in the range of (A) / epoxy resin=100 / 1 to 1 / 100.

[0173] When an epoxy resin is added, a curing agent for curing the epoxy resin can be used in combination with the curable composition according to the present disclosure. There are no particular limitations on the epoxy resin curing agent that can be used, and any commonly used epoxy resin curing agent can be used.

[0174] When a curing agent for an epoxy resin is used, the amount used is preferably in the range of 0.1 to 300 parts by weight per 100 parts by weight of the epoxy resin.

[0175] <<Preparation of Curable Composition>> The curable composition according to the present disclosure can be prepared as a one-component composition in which all ingredients are mixed in advance and stored in a sealed state, and which cures with moisture in the air after application, or as a two-component composition in which ingredients such as a curing catalyst, a filler, a plasticizer, and water are separately mixed as a curing agent, and the ingredients are mixed with the organic polymer composition before use. From the viewpoint of workability, the one-component composition is preferred.

[0176] When the curable composition is a one-component type, all of the components are blended in advance, and therefore, it is preferable to dehydrate and dry the components containing water before use, or to dehydrate them under reduced pressure during blending and kneading. In addition to the dehydration and drying method, the storage stability can be further improved by adding an alkoxysilane compound such as n-propyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, vinylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, or γ-glycidoxypropyltrimethoxysilane.

[0177] The amount of the dehydrating agent, particularly a silicon compound capable of reacting with water such as vinyltrimethoxysilane, used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the reactive silicon group-containing organic polymer (A).

[0178] <<Applications>> The curable composition according to the present disclosure can be used for pressure-sensitive adhesives, sealing materials for buildings, ships, automobiles, roads, etc., adhesives, waterproofing materials, waterproof coating materials, mold release agents, vibration-proofing materials, vibration-damping materials, soundproofing materials, foam materials, paints, spray materials, etc. The cured products obtained by curing the curable composition according to the present disclosure have excellent flexibility and adhesiveness, and therefore are more preferably used as sealants or adhesives among these.

[0179] The compound can also be used in a variety of applications, including electrical and electronic component materials such as solar cell backside sealing materials, electrical and electronic components such as insulating coating materials for electric wires and cables, electrical insulating materials for devices, acoustic insulating materials, elastic adhesives, binders, contact adhesives, spray-type sealants, crack repair materials, tiling adhesives, adhesives for asphalt waterproofing, powder coatings, casting materials, medical rubber materials, medical pressure-sensitive adhesives, medical pressure-sensitive adhesive sheets, medical device sealants, dental impression materials, food packaging materials, joint sealants for exterior materials such as sizing boards, coating materials, anti-slip coating materials, buffer materials, primers, conductive materials for electromagnetic wave shielding, thermally conductive materials, hot melt materials, potting agents for electrical and electronic applications, films, gaskets, concrete reinforcing materials, temporary adhesives, various molding materials, and liquid sealants for rust prevention and waterproofing of wired glass and laminated glass edge surfaces (cut portions), automobile parts, trucks, buses, and other large vehicle parts, train car parts, aircraft parts, marine parts, electrical parts, and various machine parts. Taking automobiles as an example, the curable compositions can be used in a wide variety of applications, including the adhesive attachment of plastic covers, trim, flanges, bumpers, window mountings, interior components, and exterior parts. Furthermore, because they can adhere to a wide range of substrates, such as glass, porcelain, wood, metal, and resin moldings, either alone or with the aid of a primer, they can also be used as various types of sealing and adhesive compositions. The curable compositions of the present disclosure can also be used as adhesives for interior panels, exterior panels, tiling adhesives, stonework adhesives, ceiling finish adhesives, floor finish adhesives, wall finish adhesives, vehicle panel adhesives, adhesives for assembling electrical, electronic, and precision equipment, adhesives for bonding leather, textiles, fabrics, paper, boards, and rubber, reactive post-crosslinking pressure-sensitive adhesives, sealants for direct glazing, sealants for double-glazing, sealants for SSG construction, sealants for working joints in buildings, and materials for civil engineering and bridge construction. They can also be used as adhesive materials, such as adhesive tapes and sheets.

[0180] In the following items, preferred embodiments of the present disclosure are listed, but the present invention is not limited to the following items. [Item 1] General formula (1): —Si(R １ )３－ａ X １ ａ (1) (wherein, R １ Each of X independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. １ each independently represents a hydroxyl group or a hydrolyzable group; and a is 1, 2, or 3. A curable composition comprising an organic polymer (A) having a reactive silicon group represented by the following formula (R): ２ ) ３－ｂ X ２ ｂ Si-R ３ -Si(R ２ ) ３－ｂ X ２ ｂ (2) (wherein, R ２ Each of X independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. ２ each independently represents a hydroxyl group or a hydrolyzable group; b is 1, 2, or 3. ３ represents a divalent hydrocarbon group having 1 to 50 carbon atoms. The divalent hydrocarbon group is —C(═X ３ )-R ５ -NH-, -OC(=X ３ )-R ５ -NH-, -NH-R ５ -C (=X ３ )-R ５ -NH- or -C(=X ３ )-R ５ -NH-R ５ -C (=X ３ )-. ５ represents a direct bond or a divalent hydrocarbon group having 1 to 3 carbon atoms. ３ represents an oxygen atom or a sulfur atom. ３ The divalent hydrocarbon group is —Si(R ２ ) ３－ｂ X ２ｂ [Item 2] A curable composition represented by the formula: ３ wherein the divalent hydrocarbon group has 1 to 20 carbon atoms. [Item 3] The curable composition according to Item 1 or 2, wherein b is 3. [Item 4] The curable composition according to any one of Items 1 to 3, wherein the (meth)acrylic acid ester polymer (A1) has a number average molecular weight of 2,000 or more. [Item 5] The curable composition according to any one of Items 1 to 4, wherein the organic polymer (A) further contains a polyoxyalkylene polymer (A2). [Item 6] The curable composition according to Item 5, wherein the weight ratio of the (meth)acrylic acid ester polymer (A1):polyoxyalkylene polymer (A2) is 20:80 to 60:40. [Item 7] The curable composition according to any one of Items 1 to 6, wherein the content of the silane compound (B) is 0.1 to 30 parts by weight per 100 parts by weight of the organic polymer (A). [Item 8] A cured product obtained by curing the curable composition according to any one of Items 1 to 7.

[0181] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The number average molecular weight in the examples is a GPC molecular weight measured under the following conditions: Solution delivery system: HLC-8420 GPC manufactured by Tosoh Corporation; Column: TSKgel Super H series manufactured by Tosoh Corporation; Solvent: THF (tetrahydrofuran); Molecular weight: Polystyrene equivalent; Measurement temperature: 40°C

[0182] Synthesis Example 1 A solution of 11.5 g of azobis-2-methylbutyronitrile as a polymerization initiator dissolved in a mixture of 300 g of methyl methacrylate, 115 g of 2-ethylhexyl acrylate, 46 g of γ-methacryloyloxypropyltrimethoxysilane, 37 g of γ-mercaptopropyltrimethoxysilane, and 140 g of IBA was added dropwise over 5 hours to 200 g of isobutyl alcohol (IBA) heated to 105° C. Thereafter, polymerization was carried out for 2 hours to obtain a (meth)acrylic acid ester copolymer (A1-1) having a solids concentration of 60%, a number average molecular weight of 2,200, and an average of 1.5 trimethoxysilyl groups per molecule.

[0183] Synthesis Example 2 A solution of 11.5 g of azobis-2-methylbutyronitrile as a polymerization initiator dissolved in a mixture of 23 g of methyl methacrylate, 277 g of butyl acrylate, 115 g of 2-ethylhexyl acrylate, 46 g of γ-methacryloyloxypropyltrimethoxysilane, 37 g of γ-mercaptopropyltrimethoxysilane, and 140 g of IBA was added dropwise over 5 hours to 200 g of isobutyl alcohol (IBA) heated to 105° C. Thereafter, polymerization was carried out for 2 hours to obtain a (meth)acrylic acid ester copolymer (A1-2) having a solids concentration of 60% and a number average molecular weight of 2,200, and containing an average of 1.5 trimethoxysilyl groups per molecule.

[0184] Synthesis Example 3 A solution of 11.5 g of azobis-2-methylbutyronitrile as a polymerization initiator dissolved in a mixture of 300 g of methyl methacrylate, 115 g of 2-ethylhexyl acrylate, 46 g of γ-methacryloyloxypropyldimethoxymethylsilane, 37 g of γ-mercaptopropyldimethoxymethylsilane, and 140 g of IBA was added dropwise over 5 hours to 200 g of isobutyl alcohol (IBA) heated to 105° C. Thereafter, polymerization was carried out for 2 hours to obtain a (meth)acrylic acid ester copolymer (A1-3) having a solids concentration of 60% and a number average molecular weight of 2,200, and containing an average of 1.5 dimethoxymethylsilyl groups per molecule.

[0185] Synthesis Example 4: Using diethyl 2,5-dibromoadipate (3.51 parts by weight) as an initiator, cuprous bromide (0.84 parts by weight) as a catalyst, and pentamethyldiethylenetriamine as a catalytic ligand, butyl acrylate (100.0 parts by weight) was polymerized in acetonitrile at approximately 80-90°C to obtain a polyacrylic ester having bromine groups at both ends. The polymerization reaction rate was adjusted appropriately by adjusting the amount of pentamethyldiethylenetriamine. Subsequently, the terminal bromine groups of the polymer were reacted with 1,7-octadiene in acetonitrile using a pentamethyldiethylenetriamine complex of cuprous bromide as a catalyst to obtain a polyacrylic ester. The 1,7-octadiene was used in an amount of 21 molar equivalents relative to the initiator. After the reaction, unreacted 1,7-octadiene was recovered by devolatilization. The resulting polymer was purified by adsorption, heated to approximately 190°C for debromination, and then purified by adsorption again to obtain a polyacrylic acid ester having alkenyl groups at both ends. The resulting polyacrylic acid ester having alkenyl groups at both ends was reacted with methyldimethoxysilane at 100°C for 1 hour with the alkenyl groups of the polyacrylic acid ester using 300 ppm of an isopropanol solution of a platinum vinylsiloxane complex containing 3 wt% platinum as a catalyst. The reaction was carried out in the presence of methyl orthoformate, using 3.2 molar equivalents of methyldimethoxysilane relative to the alkenyl groups. After the reaction, unreacted methyldimethoxysilane and methyl orthoformate were removed by devolatilization to obtain a methyldimethoxysilyl-terminated polyacrylic acid ester (A1-4). The number-average molecular weight of the resulting polymer was 13,800, the molecular weight distribution was 1.3, and the number of silyl groups introduced per molecule was 1.8.

[0186] Synthesis Example 5 18 g of 1,4-butanediol and 82 g of 3-isocyanatopropyltrimethoxysilane were placed in a 300 mL flask, and the mixture was reacted with stirring at 60° C. for 5 hours using an oil bath to obtain a silane compound (B-2).

[0187] Synthesis Example 6 46.6 g of 3-aminopropyltrimethoxysilane and 53.4 g of 3-isocyanatopropyltrimethoxysilane were placed in a 300 mL flask and reacted with mixing and stirring at room temperature for 1 hour to obtain a silane compound (B-3).

[0188] Synthesis Example 7 30 g of Neostan U-28 (2-ethylhexanoic acid tin, manufactured by Nitto Kasei Co., Ltd.) and 10 g of laurylamine were weighed into a 100 mL plastic container, and the mixture was stirred with a spatula to be homogeneous and reacted to obtain a curing catalyst (C-1).

[0189] Example 1 Kaneka Silyl (registered trademark) SAX530 (manufactured by Kaneka Corporation) as a polyoxyalkylene polymer (A2-1) having a reactive silicon group, a (meth)acrylic acid ester polymer (A1-1) having a reactive silicon group, a silane compound (B-1), and a curing catalyst (C-1) were weighed into a 100 mL plastic container according to the composition ratios (by weight) shown in Table 1, and the mixture was quickly stirred with a spatula for 1 minute to become uniform. The container was placed in a centrifuge, and the bubbles in the mixture were degassed to obtain the curable composition of Example 1.

[0190] (Examples 2 to 8, Comparative Examples 1 to 7) The curable compositions of Examples 2 to 8 and Comparative Examples 1 to 7 were obtained in the same manner as in Example 1, except that the type or amount of each component was changed according to the composition ratio (by weight) shown in Table 1. The amount of each silane compound in Examples 1 to 8 and Comparative Example 2 was 10 mmol in molar units.

[0191] The names of the silane compounds (B) or comparative compounds (B') used in the examples and comparative examples are as follows: Each silane compound (B) has two reactive silicon groups per molecule, whereas the comparative compound (B') has only one reactive silicon group per molecule. (B-1): 1,6-bis(trimethoxysilyl)hexane (manufactured by Tokyo Chemical Industry Co., Ltd.), molecular weight 326.5, R in formula (2) ３ Number of carbon atoms: 6

[0192]

[0193] (B-2): 4-(3-trimethoxysilylpropylcarbamoyloxy)butyl-N-(3-trimethoxysilylpropyl)carbamate, molecular weight 500.7, R in formula (2) ３ Number of carbon atoms: 10

[0194]

[0195] (B-3): N,N'-bis(3-trimethoxysilylpropyl)urea, molecular weight 384.6, R in formula (2) ３ Number of carbon atoms: 6

[0196]

[0197] (B'-1): Vinyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), molecular weight 148.2

[0198] <Viscosity> The viscosity of the curable composition was measured at a measurement temperature of 23° C. using an E-type viscometer (RE-85U manufactured by Tokyo Keiki) with a measurement cone of 3°×R14. The results are shown in Table 1.

[0199] <Tensile Properties> The obtained curable composition was filled into a mold and cured for 7 days at 23°C and 50% relative humidity to produce a sheet-like cured product with a thickness of approximately 1 mm. The sheet-like cured product was punched into a No. 3 dumbbell shape and subjected to a tensile test at 23°C and 50% relative humidity to measure the breaking strength (TB) and elongation at break (EB). The measurement was performed using an autograph (AGS-J, manufactured by Shimadzu Corporation) at a tensile speed of 500 mm / min. The results are shown in Table 1.

[0200]

[0201] According to Table 1, Examples 1 to 3, which contained a (meth)acrylic acid ester polymer (A1-1) having a reactive silicon group, a silane compound (B) having two or more reactive silicon groups, and a curing catalyst (C), gave cured products with lower viscosity and higher strength than Comparative Example 1, which did not contain the silane compound (B). On the other hand, Comparative Example 2, which contained a silane compound (B') having only one reactive silicon group, had the same strength as Comparative Example 1.

[0202] Furthermore, Examples 4 and 5, which contained the (meth)acrylic acid ester polymer (A1-2) having a reactive silicon group, the silane compound (B) having two or more reactive silicon groups, and the curing catalyst (C), gave curable compositions with lower viscosity and cured products with higher strength, compared to Comparative Example 3, which did not contain the silane compound (B).

[0203] Furthermore, Examples 6 and 7, which contained the (meth)acrylic acid ester polymer (A1-3) having a reactive silicon group, the silane compound (B) having two or more reactive silicon groups, and the curing catalyst (C), gave curable compositions with lower viscosity and cured products with higher strength than Comparative Example 4, which did not contain the silane compound (B).

[0204] Furthermore, Example 8, which contained the (meth)acrylic acid ester-based polymer (A1-4) having a reactive silicon group, the silane compound (B) having two or more reactive silicon groups, and the curing catalyst (C), gave a curable composition with a lower viscosity and a cured product with higher strength than Comparative Example 5, which did not contain the silane compound (B).

[0205] On the other hand, in Comparative Examples 6 and 7, which did not contain the (meth)acrylic acid ester polymer (A1) having a reactive silicon group, all curable compositions provided cured products with similar strength, regardless of the presence or absence of the silane compound (B). This shows that in systems not containing the (meth)acrylic acid ester polymer (A1) having a reactive silicon group, the addition of the silane compound (B) does not provide an effect of improving strength. Therefore, it can be said that the improvement in strength is due to the synergistic effect of the (meth)acrylic acid ester polymer (A1) having a reactive silicon group and the silane compound (B).

Claims

1. General formula (1): -Si(R １ ) ３－ａ X １ ａ (1) (wherein, R １ Each of X independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. １ each independently represents a hydroxyl group or a hydrolyzable group; and a is 1, 2, or 3. A curable composition comprising an organic polymer (A) having a reactive silicon group represented by the following formula (R): ２ ) ３－ｂ X ２ ｂ Si-R ３ -Si(R ２ ) ３－ｂ X ２ ｂ (2) (wherein, R ２ Each of X independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. ２ each independently represents a hydroxyl group or a hydrolyzable group; b is 1, 2, or 3. ３ represents a divalent hydrocarbon group having 1 to 50 carbon atoms. The divalent hydrocarbon group is —C(═X ３ )-R ５ -NH-, -OC(=X ３ )-R ５ -NH-, -NH-R ５ -C (=X ３ )-R ５ -NH- or -C(=X ３ )-R ５ -NH-R ５ -C (=X ３ )-. ５ represents a direct bond or a divalent hydrocarbon group having 1 to 3 carbon atoms. ３ represents an oxygen atom or a sulfur atom. ３ The divalent hydrocarbon group is —Si(R ２ ) ３－ｂ X ２ ｂ The curable composition may further have a group represented by the following formula:

2. R ３ The curable composition according to claim 1, wherein the divalent hydrocarbon group has 1 to 20 carbon atoms.

3. A curable composition according to claim 1 or 2, wherein b is 3.

4. The curable composition according to claim 1 or 2, wherein the (meth)acrylic acid ester polymer (A1) has a number average molecular weight of 2,000 or more.

5. The curable composition according to claim 1 or 2, wherein the organic polymer (A) further contains a polyoxyalkylene polymer (A2).

6. The curable composition according to claim 5, wherein the weight ratio of the (meth)acrylic acid ester polymer (A1):polyoxyalkylene polymer (A2) is 20:80 to 60:

40.

7. The curable composition according to claim 1 or 2, wherein the content of the silane compound (B) is 0.1 to 30 parts by weight per 100 parts by weight of the organic polymer (A).

8. A cured product obtained by curing the curable composition according to claim 1 or 2.

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