Curable composition and cured product thereof

Abstract

To provide a curable composition which contains an organic polymer having a reactive silicon group and can form a cured product having high strength.SOLUTION: There is provided a curable composition which comprises a (meth)acrylic ester-based copolymer (A) having a reactive silicon group and a polyester (B) having a reactive silicon group. A monomer component constituting the (meth)acrylic ester-based copolymer (A) contains a (meth)acrylic ester (a1), a polymer (a2) having more than one (meth)acryloyl group in the molecule and a chain transfer agent (a3) having a mercapto group. The monomer component further contains a monomer (a4) having a reactive silicon group and a polymerizable unsaturated group and / or the chain transfer agent (a3) having a mercapto group further contains a reactive silicon group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition containing a polymer having a reactive silicon group, and a cured product thereof. [Background technology]

[0002] Organic polymers that have hydroxyl or hydrolyzable groups on the silicon atom and can form siloxane bonds through hydrolysis and condensation reactions (hereinafter referred to as "reactive silicon groups") react with moisture even at room temperature. It is known that such organic polymers can be crosslinked by the siloxane condensation reaction of the reactive silicon groups to produce rubber-like cured products.

[0003] Among these organic polymers, polyoxyalkylene polymers having reactive silicon groups have a relatively low viscosity, which makes them easy to work with when preparing and using blended compositions. Furthermore, the resulting cured products have a good balance of mechanical properties, weather resistance, dynamic durability, and other performance characteristics, making them widely used in applications such as sealants, adhesives, and paints (see Patent Document 1).

[0004] In order to improve the weather resistance and adhesiveness of polyoxyalkylene polymers having reactive silicon groups, a curable composition containing a reactive silicon group-containing polyoxyalkylene polymer in combination with a reactive silicon group-containing (meth)acrylic acid ester polymer is known (see Patent Document 2). This curable composition is used as a highly weather-resistant sealant or industrial adhesive.

[0005] On the other hand, Patent Document 3 aims to overcome the drawback of slow curing speed of one-component moisture-curing adhesives that use modified silicone or acrylic-modified silicone, and describes a reactive silicon group-containing graft copolymer synthesized by radical polymerization of an oligomer having a polyether skeleton and double bonds at both ends, a vinyl monomer such as a (meth)acrylic acid ester, and a chain transfer agent as a curable resin with fast curing speed and excellent adhesive properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 52-73998 [Patent Document 2] Japanese Unexamined Patent Publication No. 59-122541 [Patent Document 3] Patent No. 5082851 Summary of the Invention [Problem to be solved by the invention]

[0007] It is desirable that the curable composition containing the organic polymer having a reactive silicon group forms a cured product having high strength upon curing.

[0008] 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 form a cured product with high strength. [Means for solving the problem]

[0009] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by forming a reactive silicon group-containing (meth)acrylic acid ester polymer from a specific monomer and a chain transfer agent, and by using a reactive silicon group-containing polyester in combination with the polymer, and have thus completed the present invention.

[0010] That is, the present invention provides a (meth)acrylic acid ester copolymer (A) having a reactive silicon group represented by the following general formula (1), and The polyester (B) contains a reactive silicon group represented by the following general formula (1): The monomer components constituting the (meth)acrylic acid ester copolymer (A) are (Meth)acrylic acid ester (a1), A polymer (a2) having more than one (meth)acryloyl group in the molecule, and a chain transfer agent (a3) ​​having a mercapto group, The present invention relates to a curable composition, wherein the monomer component further contains a monomer (a4) having a reactive silicon group and a polymerizable unsaturated group, and / or the chain transfer agent (a3) ​​having a mercapto group further has a reactive silicon group. -SiR 1 3-a X a (1) (In the formula, R 1 represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; X represents a hydroxyl group or a hydrolyzable group; and a is 2 or 3. Preferably, the polymer (a2) is a polyoxyalkylene polymer (a2'') having more than one (meth)acryloyl group in the molecule. Preferably, the polymer (a2) is a (meth)acrylic acid ester polymer (a2') having more than one (meth)acryloyl group in the molecule. Preferably, the molar ratio of polymer (a2) / chain transfer agent (a3) ​​having a mercapto group is 0.05 or more. Preferably, the polyester (B) is crystalline. The curable composition is preferably a hot-melt type curable composition. The present invention also relates to a cured product obtained by curing the curable composition. [Effects of the Invention]

[0011] 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 is capable of forming a cured product with high strength. The curable composition according to the present invention can be suitably used as a hot-melt type curable composition. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes specific embodiments of the present invention, but the present invention is not limited to these embodiments.

[0013] The curable composition according to this embodiment contains a (meth)acrylic acid ester copolymer (A) having a reactive silicon group, and a polyester (B) having a reactive silicon group.

[0014] <<(Meth)acrylic acid ester copolymer (A) having reactive silicon groups>> <Reactive silicon group> The (meth)acrylic acid ester copolymer (A) has a reactive silicon group represented by the following general formula (1) at the molecular chain terminal and / or side chain (non-terminal site). -SiR 1 3-a X a (1) (In the formula, R 1 represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; X represents a hydroxyl group or a hydrolyzable group; and a represents 2 or 3.

[0015] R 1 The hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms. 1 Specific examples of include a methyl group, an ethyl group, a chloromethyl group, a methoxymethyl group, and an N,N-diethylaminomethyl group. Preferred are a methyl group, an ethyl group, a chloromethyl group, and a methoxymethyl group, and more preferred are a methyl group and a methoxymethyl group.

[0016] Examples of X include halogen, alkoxy group, acyloxy group, ketoximate group, amino group, amide group, acid amide group, aminooxy group, mercapto group, alkenyloxy group, etc. Among these, alkoxy group is more preferred because it is mildly hydrolyzable and easy to handle, and methoxy group and ethoxy group are particularly preferred.

[0017] Specific examples of the reactive silicon group contained in the (meth)acrylic acid ester copolymer (A) include, but are not limited to, a trimethoxysilyl group, a triethoxysilyl group, a tris(2-propenyloxy)silyl group, a triacetoxysilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a dimethoxyethylsilyl group, a (chloromethyl)dimethoxysilyl group, a (chloromethyl)diethoxysilyl group, a (methoxymethyl)dimethoxysilyl group, a (methoxymethyl)diethoxysilyl group, an (N,N-diethylaminomethyl)dimethoxysilyl group, and an (N,N-diethylaminomethyl)diethoxysilyl group. Among these, methyldimethoxysilyl group, trimethoxysilyl group, triethoxysilyl group, (chloromethyl)dimethoxysilyl group, (methoxymethyl)dimethoxysilyl group, (methoxymethyl)diethoxysilyl group, and (N,N-diethylaminomethyl)dimethoxysilyl group are preferred because they exhibit high activity and give cured products with good mechanical properties. Trimethoxysilyl group and triethoxysilyl group are more preferred, and trimethoxysilyl group is even more preferred, because they give cured products with a high Young's modulus.

[0018] The reactive silicon group equivalent of the (meth)acrylic acid ester copolymer (A) is not particularly limited, but is preferably 0.2 mmol / g or more, more preferably 0.5 mmol / g or more, and even more preferably 0.6 mmol / g or more. The reactive silicon group equivalent is preferably 2.0 mmol / g or less, and more preferably 1.0 mmol / g or less in order to prevent a decrease in elongation of the cured product. To obtain a cured product with high rigidity and flexibility, the reactive silicon group equivalent is particularly preferably 0.5 mmol / g or more and 1.0 mmol / g or less.

[0019] <Monomer component> The (meth)acrylic acid ester copolymer (A) is a polymer formed by copolymerizing monomer components containing at least a (meth)acrylic acid ester (a1), a polymer (a2) having more than one (meth)acryloyl group in the molecule, and a chain transfer agent (a3) ​​having a mercapto group. In this application, "(meth)acrylic" means "acrylic and / or methacrylic."

[0020] The (meth)acrylic acid ester copolymer (A) will have reactive silicon groups when it satisfies either or both of the following two conditions: Condition 1: The monomer component further contains a monomer (a4) having a reactive silicon group and a polymerizable unsaturated group. Condition 2: The chain transfer agent (a3) ​​having a mercapto group further has a reactive silicon group. A curable composition containing a reactive silicon group-containing (meth)acrylic acid ester copolymer (A) that satisfies the above requirements can form a cured product with high strength by curing.

[0021] To obtain a cured product with high elongation, it is preferable that the reactive silicon groups introduced under condition 2 are more than the reactive silicon groups introduced under condition 1. Specifically, the reactive silicon group equivalent introduced under condition 1 is preferably 0.01 mmol / g or more, more preferably 0.03 mmol / g or more, and even more preferably 0.05 mmol / g or more. The reactive silicon group equivalent introduced under condition 1 is preferably 1.0 mmol / g or less, and more preferably 0.5 mmol / g or less. On the other hand, the reactive silicon group equivalent introduced under condition 2 is preferably 0.2 mmol / g or more, more preferably 0.3 mmol / g or more, and even more preferably 0.5 mmol / g or more. The reactive silicon group equivalent introduced under condition 2 is preferably 1.5 mmol / g or less, and more preferably 1.0 mmol / g or less.

[0022] To obtain a cured product with high strength, it is preferable to introduce reactive silicon groups under both Condition 1 and Condition 2. Specifically, the reactive silicon group equivalent introduced under Condition 1 is preferably 0.1 mmol / g or more, more preferably 0.2 mmol / g or more, and even more preferably 0.3 mmol / g or more. The reactive silicon group equivalent introduced under Condition 1 is preferably 1.8 mmol / g or less, and more preferably 1.0 mmol / g or less. On the other hand, the reactive silicon group equivalent introduced under Condition 2 is preferably 0.1 mmol / g or more, more preferably 0.2 mmol / g or more, and even more preferably 0.3 mmol / g or more. The reactive silicon group equivalent introduced under Condition 2 is preferably 1.5 mmol / g or less, and more preferably 1.0 mmol / g or less.

[0023] <(Meth)acrylic acid ester (a1)> The (meth)acrylic acid ester (a1) is not particularly limited, and examples thereof 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, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate. Examples of such an acrylate include ethylene oxide adducts of (meth)acrylic acid, 2,2,2-trifluoroethyl (meth)acrylate, 3,3,3-trifluoropropyl (meth)acrylate, 3,3,4,4,4-pentafluorobutyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, trifluoromethyl (meth)acrylate, perfluoroethyl (meth)acrylate, bis(trifluoromethyl)methyl (meth)acrylate, 2-trifluoromethyl-2-perfluoroethylethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, chloroethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, and 2-aminoethyl (meth)acrylate. One type may be used alone, or two or more types may be used in combination. The (meth)acrylic acid ester (a1) is preferably a (meth)acrylic acid alkyl ester.

[0024] From the viewpoint of achieving both flexibility and high rigidity, the content of the (meth)acrylic acid ester (a1) is preferably 30% by weight or more, more preferably 40% by weight or more, and even more preferably 45% by weight or more, based on the total amount of the monomer components constituting the (meth)acrylic acid ester copolymer (A). The upper limit is preferably 80% by weight or less, more preferably 70% by weight or less, and even more preferably 65% ​​by weight or less.

[0025] Since a cured product with high strength can be obtained, the (meth)acrylic acid ester (a1) preferably contains a (meth)acrylic acid alkyl ester having an alkyl carbon number of 1 to 4. The (meth)acrylic acid alkyl ester having an alkyl carbon number of 1 to 4 is preferably contained in an amount of 30% by weight or more, more preferably 35% by weight or more, and even more preferably 40% by weight or more, based on the total amount of monomer components constituting the (meth)acrylic acid ester-based copolymer (A). The upper limit is preferably 70% by weight or less, more preferably 60% by weight or less, and even more preferably 55% by weight or less.

[0026] Since the (meth)acrylic acid ester (a1) forms a hard polymer chain and can give a cured product with high strength, it preferably contains at least one monomer selected from the group consisting of methacrylic acid ester, isobornyl acrylate, dicyclopentenyl acrylate, and dicyclopentanyl acrylate. In particular, the proportion of at least one monomer selected from the group consisting of methacrylic acid ester, isobornyl acrylate, dicyclopentenyl acrylate, and dicyclopentanyl acrylate in the total amount of the monomer components excluding polymer (a2) is preferably 60% by weight or more, more preferably 70% by weight or more.

[0027] <Polymer (a2) Having More Than One (Meth)acryloyl Group in the Molecule> The polymer (a2) is itself a polymer, but is one of the monomers constituting the (meth)acrylic acid ester copolymer (A). The polymer (a2) can be copolymerized with other monomers, such as the (meth)acrylic acid ester (a1), due to the presence of a (meth)acryloyl group. Furthermore, since the polymer (a2) has more than one (meth)acryloyl group per molecule, it can function as a so-called multifunctional macromonomer. The main chain skeleton of the polymer (a2) (the second molecular chain, described below) can form a structure in the (meth)acrylic acid ester copolymer (A) that crosslinks two molecular chains (the first molecular chain, described below) that are primarily composed of the (meth)acrylic acid ester (a1). Hereinafter, the polymer (a2) will also be referred to as the multifunctional macromonomer (a2).

[0028] The (meth)acryloyl group contained in the polyfunctional macromonomer (a2) is preferably represented by the following formula (4). CH2=C(R 7 )-COO-Z (4) (In the formula, R 7 represents hydrogen or a methyl group. Z represents the main chain skeleton of the polyfunctional macromonomer (a2).

[0029] The polyfunctional macromonomer (a2) has, on average, more than one (meth)acryloyl group per molecule. The average number of (meth)acryloyl groups per molecule of the polyfunctional macromonomer (a2) is preferably 1.1 to 5, more preferably 1.3 to 4, even more preferably 1.6 to 2.5, and particularly preferably 1.8 to 2.0. The polyfunctional macromonomer (a2) may have only acryloyl groups, only methacryloyl groups, or both acryloyl and methacryloyl groups, as the (meth)acryloyl groups.

[0030] The polyfunctional macromonomer (a2) may have a (meth)acryloyl group at either or both of the molecular chain terminal and the side chain of the polymer. From the viewpoint of excellent mechanical properties, it is preferable to have the group at the molecular chain terminal. In particular, it is particularly preferable that the polyfunctional macromonomer (a2) has a linear main chain skeleton and has a (meth)acryloyl group at each of both ends of the molecular chain.

[0031] The main chain skeleton of the polyfunctional macromonomer (a2) is preferably a (meth)acrylic acid ester polymer or a polyoxyalkylene polymer. Hereinafter, a polyfunctional macromonomer (a2) whose main chain skeleton is a (meth)acrylic acid ester polymer will be referred to as (a2'), and a polyfunctional macromonomer (a2) whose main chain skeleton is a polyoxyalkylene polymer will be referred to as (a2").

[0032] First, the polyfunctional macromonomer (a2') will be explained. The monomer constituting the main chain skeleton of the polyfunctional macromonomer (a2') is not particularly limited, and various (meth)acrylic monomers can be used. Examples of the (meth)acrylic monomer include (meth)acrylic acid, 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, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. , ethylene oxide adducts of (meth)acrylic acid, 2,2,2-trifluoroethyl (meth)acrylate, 3,3,3-trifluoropropyl (meth)acrylate, 3,3,4,4,4-pentafluorobutyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, trifluoromethyl (meth)acrylate, perfluoroethyl (meth)acrylate, bis(trifluoromethyl)methyl (meth)acrylate, 2-trifluoromethyl-2-perfluoroethylethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, chloroethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, and 2-aminoethyl (meth)acrylate.

[0033] Furthermore, other monomers copolymerizable with the (meth)acrylic monomers may be used in combination. Examples of such other monomers include styrene-based monomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, and styrenesulfonic acid; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; maleic acid and its derivatives such as maleic acid, maleic anhydride, maleic acid monoalkyl esters, and maleic acid dialkyl esters; fumaric acid and its derivatives such as fumaric acid, fumaric acid monoalkyl esters, and fumaric acid dialkyl esters; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, and hexamethylmaleimide. Examples of the other monomers include maleimide monomers such as xylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, and cyclohexylmaleimide; vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; olefin monomers such as ethylene and propylene; conjugated diene monomers such as butadiene and isoprene; (meth)acrylamide; (meth)acrylonitrile; and vinyl monomers such as vinyl chloride, vinylidene chloride, allyl chloride, allyl alcohol, ethyl vinyl ether, and butyl vinyl ether. These other monomers may be used alone or in combination.

[0034] The main chain skeleton of the polyfunctional macromonomer (a2') is preferably composed of a soft polymer. Specifically, the monomer components forming the main chain skeleton of the polyfunctional macromonomer (a2') preferably contain 60% by weight or more, more preferably 70% by weight or more, of acrylate esters (excluding isobornyl acrylate, dicyclopentenyl acrylate, and dicyclopentanyl acrylate). The upper limit may be 100% by weight.

[0035] The method for synthesizing the polyfunctional macromonomer (a2') is not particularly limited, but for example, the following methods can be used. The following methods may be used in combination. (i) A method in which a monomer having a reactive functional group (V group) (e.g., acrylic acid, 2-hydroxyethyl acrylate) is copolymerized with a (meth)acrylic monomer, and then the resulting copolymer is reacted with a compound having a functional group reactive with the V group and a (meth)acryloyl group (e.g., 2-isocyanatoethyl (meth)acrylate). (ii) A method in which (meth)acrylic monomers are polymerized by living radical polymerization, and then (meth)acryloyl groups are introduced into the molecular chain terminals (preferably both molecular chain terminals). Of these methods, method (ii) is preferred because it allows for the introduction of (meth)acryloyl groups to molecular chain terminals. Examples of "living radical polymerization" include those using cobalt porphyrin complexes, as disclosed in the Journal of the American Chemical Society (J. Am. Chem. Soc.), Vol. 116, p. 7943, 1994; those using nitroxide radicals, as disclosed in JP-A-2003-500378; and atom transfer radical polymerization (ATRP), as disclosed in JP-A-11-130931, which uses organic halides or sulfonyl halides as initiators and transition metal complexes as catalysts. Atom transfer radical polymerization is most preferred because it allows for the easy introduction of (meth)acryloyl groups to molecular chain terminals.

[0036] It is also possible to use a method of obtaining a (meth)acrylic polymer using a metallocene catalyst and a thiol compound having at least one reactive silicon group in the molecule, as disclosed in JP-A-2001-040037.

[0037] Next, the polyfunctional macromonomer (a2'') will be described. The polyoxyalkylene polymer that is the main chain skeleton of the polyfunctional macromonomer (a2″) is not particularly limited, and examples thereof include polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer, polyoxypropylene-polyoxybutylene copolymer, etc. Among these, polyoxypropylene is preferred.

[0038] The main chain skeleton of the polyoxyalkylene polymer may be linear or branched, but is preferably linear.

[0039] The method for synthesizing the polyfunctional macromonomer (a2") is not particularly limited, but an example thereof includes a method in which a polyoxyalkylene polymer having more than one hydroxyl group in the molecule (preferably a linear polyoxyalkylene polymer having hydroxyl groups at both ends) is prepared, and a (meth)acryloyl group is introduced using the hydroxyl group.

[0040] As an example of a method for synthesizing the polyfunctional macromonomer (a2"), a compound having an isocyanate group and a (meth)acryloyl group can be reacted with a polyoxyalkylene polymer having a hydroxyl group to form a urethane bond and introduce a (meth)acryloyl group. Specific examples of the compound having an isocyanate group and a (meth)acryloyl group include isocyanate ethyl (meth)acrylate, isocyanate propyl (meth)acrylate, isocyanate butyl (meth)acrylate, and isocyanate hexyl (meth)acrylate.

[0041] As another example of a method for synthesizing the polyfunctional macromonomer (a2"), a polyoxyalkylene polymer having a hydroxyl group can be reacted with a diisocyanate compound to introduce an isocyanate group into the polymer, and then a compound having a hydroxyl group and a (meth)acryloyl group can be reacted to introduce a (meth)acryloyl group. Specific examples of the diisocyanate compound include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-diphenylmethane diisocyanate. Specific examples of the compound having a hydroxyl group and a (meth)acryloyl group include, for example, hydroxybutyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate.

[0042] As yet another example of the synthesis method of the polyfunctional macromonomer (a2″), a polyoxyalkylene polymer having a hydroxyl group is reacted with an acid anhydride to introduce a carboxyl group into the polymer, and then a compound having an epoxy group and a (meth)acryloyl group is reacted to introduce a (meth)acryloyl group. Specific examples of the acid anhydride include succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhimic anhydride, trimellitic anhydride, methylnadic anhydride, and dodecylsuccinic anhydride. Specific examples of the compound having an epoxy group and a (meth)acryloyl group include glycidyl (meth)acrylate.

[0043] Still another example of a method for synthesizing the polyfunctional macromonomer (a2") is a method in which methacrylic acid or acrylic acid is subjected to dehydration condensation with a polyoxyalkylene polymer having a hydroxyl group. In order to carry out the reaction under milder conditions, there is also a method in which a polyoxyalkylene polymer having a hydroxyl group is reacted with methacrylic acid chloride, methacrylic acid bromide, methacrylic acid iodide, acrylic acid chloride, acrylic acid bromide, acrylic acid iodide, or the like.

[0044] The number-average molecular weight of the polyfunctional macromonomer (a2) is not particularly limited, but from the viewpoint of achieving both the mechanical properties and adhesiveness exhibited by the cured product and ease of handling of (a2), it is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more, and is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 40,000 or less, and particularly preferably 30,000 or less.

[0045] The weight-average molecular weight of the polyfunctional macromonomer (a2) is not particularly limited, but from the viewpoint of achieving both the mechanical properties and adhesiveness exhibited by the cured product and ease of handling of (a2), it is preferably 500 or more, more preferably 1,000 or more, and more preferably 2,500 or more, and is preferably 130,000 or less, more preferably 65,000 or less, even more preferably 60,000 or less, and even more preferably 30,000 or less.

[0046] The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polyfunctional macromonomer (a2) is not particularly limited, but is preferably narrow. Specifically, it is preferably less than 2.0, more preferably 1.6 or less, even more preferably 1.5 or less, even more preferably 1.4 or less, particularly preferably 1.3 or less, and most preferably 1.2 or less.

[0047] The number average molecular weight (Mn) and weight average molecular weight (Mw) of the polyfunctional macromonomer (a2) are values ​​measured by GPC (polystyrene equivalent), and the detailed measurement method will be described in the Examples.

[0048] The (meth)acrylic acid ester copolymer (A) has a molecular chain mainly composed of a (meth)acrylic acid ester (a1) and a molecular chain derived from the main chain skeleton of a polyfunctional macromonomer (a2). Since the polyfunctional macromonomer (a2) has more than one (meth)acryloyl group, which is a polymerizable group, per molecule, the (meth)acrylic acid ester copolymer (A) may have a structure in which more than one molecular chain mainly composed of a (meth)acrylic acid ester (a1) is bonded to each molecular chain derived from the main chain skeleton of the polyfunctional macromonomer (a2). The molecular chain derived from the main chain skeleton of the polyfunctional macromonomer (a2) may be introduced into either the terminal or side chain (non-terminal portion) of the molecular chain mainly composed of the (meth)acrylic acid ester (a1). However, from the viewpoint of adhesiveness, it is preferably introduced into the side chain.

[0049] In particular, when the polyfunctional macromonomer (a2) has a (meth)acryloyl group at each end of the main chain, an H-type structure can be formed in which a molecular chain composed mainly of (meth)acrylic acid ester (a1) is bonded to each end of the molecular chain derived from the main chain of the polyfunctional macromonomer (a2). Here, the molecular chain derived from the main chain of the polyfunctional macromonomer (a2) corresponds to the horizontal bar of the H, and the molecular chain composed mainly of the (meth)acrylic acid ester (a1) corresponds to the two vertical bars included in the H. The H-type structure will be described later.

[0050] The content of the polyfunctional macromonomer (a2) is preferably 1% by weight or more and 70% by weight or less, more preferably 5% by weight or more and 60% by weight or less, even more preferably 10% by weight or more and 50% by weight or less, and particularly preferably 15% by weight or more and 45% by weight or less, based on the total amount of the monomer components constituting the (meth)acrylic acid ester copolymer (A). In particular, when a cured product with a high Young's modulus is to be obtained, the content of the polyfunctional macromonomer (a2) is preferably less than 35% by weight. On the other hand, when a cured product with a low Young's modulus is to be obtained, the content of the polyfunctional macromonomer (a2) is preferably 35% by weight or more.

[0051] The content of the polyfunctional macromonomer (a2) in the monomer components constituting the (meth)acrylic acid ester copolymer (A) is preferably 0.05 mol % to 6.0 mol %, more preferably 0.1 mol % to 2.3 mol %, and even more preferably 0.2 mol % to 1.5 mol %. Within these ranges, gelation during synthesis of the (meth)acrylic acid ester copolymer (A) can be suppressed while achieving the effects of using the polyfunctional macromonomer (a2).

[0052] From the viewpoint of the strength of the resulting cured product, the average number of polyfunctional macromonomers (a2) per molecule of the (meth)acrylic acid ester copolymer (A) is preferably 0.05 or more and 2.0 or less. The lower limit is more preferably 0.07 or more, and even more preferably 0.08 or more. The upper limit is more preferably 1.5 or less, and even more preferably 1.0 or less. The average number can be calculated using the following formula. Formula: number average molecular weight (g / mol) of (meth)acrylic acid ester copolymer (A) / (weight (g) of (meth)acrylic acid ester copolymer (A) / (number of moles of polyfunctional macromonomer (a2))

[0053] <Chain transfer agent (a3) ​​having a mercapto group> By including a mercapto group-containing chain transfer agent (a3) ​​in the monomer components constituting the (meth)acrylic acid ester copolymer (A), it is possible to narrow the molecular weight distribution of the (meth)acrylic acid ester copolymer (A) relatively and suppress gelation during synthesis of the (meth)acrylic acid ester copolymer (A), even though a polyfunctional macromonomer (a2) is used. It also becomes possible to preferentially synthesize polymer molecules in which one molecule of the polyfunctional macromonomer (a2) is introduced per molecule of the (meth)acrylic acid ester copolymer (A).

[0054] The chain transfer agent (a3) ​​having a mercapto group may not have a reactive silicon group, but preferably further has a reactive silicon group. The reactive silicon group is the reactive silicon group represented by the above-mentioned formula (1). By having the reactive silicon group in the chain transfer agent (a3) ​​having a mercapto group, it is possible to introduce the reactive silicon group into the terminal of the molecular chain mainly composed of the (meth)acrylic acid ester (a1).

[0055] The chain transfer agent (a3) ​​having a mercapto group is not particularly limited, and examples thereof include 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropyltrimethoxysilane, (mercaptomethyl)dimethoxymethylsilane, (mercaptomethyl)trimethoxysilane, n-dodecyl mercaptan, tert-dodecyl mercaptan, and lauryl mercaptan.

[0056] The content of the chain transfer agent (a3) ​​having a mercapto group is preferably from 1 to 15% by weight, more preferably from 2 to 10% by weight, and even more preferably from 3 to 8% by weight, based on the total amount of the monomer components constituting the (meth)acrylic acid ester copolymer (A).

[0057] The content of the chain transfer agent (a3) ​​having a mercapto group in the monomer components constituting the (meth)acrylic acid ester copolymer (A) is preferably 0.1 mol % to 20 mol %, more preferably 0.4 mol % to 15 mol %, even more preferably 0.5 mol % to 10 mol %, and particularly preferably 0.6 mol % to 8 mol %. Within these ranges, the effects of using the chain transfer agent (a3) ​​having a mercapto group can be achieved.

[0058] The content of the polyfunctional macromonomer (a2) and the content of the chain transfer agent (a3) ​​having a mercapto group improves the strength of the resulting cured product, so the molar ratio of polyfunctional macromonomer (a2) / chain transfer agent (a3) ​​having a mercapto group is preferably 0.03 or more, more preferably 0.05 or more, even more preferably 0.09 or more, and particularly preferably 0.1 or more. The upper limit of this molar ratio is not particularly limited, but is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.3 or less.

[0059] The (meth)acrylic acid ester copolymer (A) contains a substituent (-SR ) derived from the chain transfer agent (a3) ​​having a mercapto group. 8 The (meth)acrylic acid ester copolymer (A) may contain sulfur atoms because it may have a structure represented by the following formula: The sulfur atom concentration in the (meth)acrylic acid ester copolymer (A) is preferably 700 ppm or more and 20,000 ppm or less, and more preferably 1,000 ppm or more and 15,000 ppm or less.

[0060] The method for measuring the sulfur atom concentration is not particularly limited. It can be measured by known elemental analysis methods such as organic elemental analysis and X-ray fluorescence analysis. The sulfur atom concentration may also be a theoretical value calculated from the total amount of the monomer components used in the production of the (meth)acrylic acid ester-based copolymer (A) and the amount (a3) ​​of the chain transfer agent having a mercapto group.

[0061] <Monomer (a4) Having a Reactive Silicon Group and a Polymerizable Unsaturated Group> The monomer (a4) having a reactive silicon group and a polymerizable unsaturated group is an optional monomer and may not be used, but is preferably used. The reactive silicon group possessed by the monomer (a4) is the reactive silicon group represented by the above-mentioned formula (1). By using the monomer (a4), the reactive silicon group can be introduced into the side chain (non-terminal portion) of the molecular chain mainly composed of the (meth)acrylic acid ester (a1).

[0062] Examples of the monomer (a4) having a reactive silicon group and a polymerizable unsaturated group include compounds having a (meth)acryloxy group and a reactive silicon group, such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyldimethoxymethylsilane, (meth)acryloxymethyltrimethoxysilane, and (meth)acryloxymethyldimethoxymethylsilane; and compounds having a vinyl group and a reactive silicon group, such as vinyltrimethoxysilane and vinyltriethoxysilane. These compounds may be used alone or in combination of two or more.

[0063] When the monomer (a4) is used, the content of the monomer (a4) is preferably 0.1 to 50% by weight, more preferably 0.5 to 30% by weight, even more preferably 1 to 20% by weight, and particularly preferably 2 to 15% by weight, based on the total amount of the monomer components constituting the (meth)acrylic acid ester copolymer (A). From the viewpoints of improving the thixotropy of the curable composition and obtaining a cured product with high elongation, the content of the monomer (a4) is preferably 10% by weight or less.

[0064] <Other monomers (b5)> The monomer components constituting the (meth)acrylic acid ester-based copolymer (A) may or may not contain another monomer (b5) that does not fall under any of the above-described (a1) to (a4). Examples of the other monomer (b5) include (meth)acrylic monomers that do not fall under the category of the (meth)acrylic acid ester (a1) or the monomer (a4) having a reactive silicon group and a polymerizable unsaturated group, and monomers other than the (meth)acrylic monomers. Specifically, the other monomers described above for the polyfunctional macromonomer (a2') can be used.

[0065] <Molecular Weight of (Meth)acrylic Acid Ester Copolymer (A)> The number average molecular weight of the (meth)acrylic acid ester copolymer (A) is not particularly limited, but is preferably 500 to 50,000, more preferably 500 to 30,000, and particularly preferably 1,000 to 10,000, in terms of polystyrene, as measured by GPC. In particular, the number average molecular weight is preferably 7,000 or less, since a low-viscosity (meth)acrylic acid ester copolymer (A) can be obtained. Furthermore, the number average molecular weight is preferably 3,500 or less, since good adhesiveness can be achieved at low viscosity.

[0066] The weight-average molecular weight of the (meth)acrylic acid ester copolymer (A) is not particularly limited, but is preferably 500 to 80,000, more preferably 3,000 to 70,000, and particularly preferably 5,000 to 65,000, in terms of polystyrene, as measured by GPC. In particular, the weight-average molecular weight is preferably 20,000 or less, since a cured product having low viscosity and high strength can be obtained.

[0067] With regard to the weight average molecular weight of the (meth)acrylic acid ester copolymer (A) and the weight average molecular weight of the polyfunctional macromonomer (a2), the value calculated by the following formula is preferably 1.1 or more. Formula: (weight average molecular weight of copolymer (A)) / (weight average molecular weight of multifunctional macromonomer (a2)) A value calculated by the above formula of 1.1 or more means that the average number of polyfunctional macromonomers (a2) introduced per molecule of the (meth)acrylic acid ester copolymer (A) is large, and the strength of the resulting cured product can be further improved. From the viewpoint of the strength of the cured product, the value calculated by the above formula is preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more. There is no particular upper limit, but it is preferably 10 or less, more preferably 5 or less.

[0068] The molecular weight distribution of the (meth)acrylic acid ester copolymer (A) is not particularly limited, but from the viewpoint of making the (meth)acrylic acid ester copolymer (A) low in viscosity, it is preferably from 3.0 to 11.0, more preferably from 3.2 to 10.0, and even more preferably from 3.4 to 8.0. The molecular weight distribution of the (meth)acrylic acid ester copolymer (A) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

[0069] <Structure of (Meth)acrylic Acid Ester Copolymer (A)> According to a preferred embodiment, the (meth)acrylic acid ester copolymer (A) may include a triblock copolymer. The triblock copolymer has a structure in which two first molecular chains are bonded via one second molecular chain. The first molecular chain is mainly composed of a molecular chain formed by polymerization of a (meth)acrylic acid ester (a1), and the second molecular chain is composed of a main chain skeleton of a polyfunctional macromonomer (a2).

[0070] The first molecular chain is a molecular chain formed by copolymerization of (a1), (meth)acryloyl groups in (a2), (a3), optional (a4), and optional other monomers. A reactive silicon group is bonded to this first molecular chain. When the chain transfer agent (a3) ​​having a mercapto group has a reactive silicon group, the reactive silicon group is bonded to the terminal of the first molecular chain. When the monomer (a4) having a reactive silicon group and a polymerizable unsaturated group is used, the reactive silicon group is bonded to a non-terminal portion of the first molecular chain. On the other hand, the second molecular chain corresponds to the main chain skeleton of the (meth)acrylate polymer or polyoxyalkylene polymer in the polyfunctional macromonomer (a2).

[0071] The two first molecular chains and one second molecular chain are linked in a manner different from that of a conventional ABA triblock copolymer, in that both ends of the second molecular chain are linked to the non-terminal portions of the first molecular chain, respectively, i.e., the triblock copolymer has an H-type structure, in which the two vertical bars in the H correspond to the two first molecular chains and the horizontal bar in the H corresponds to one second molecular chain.

[0072] However, the (meth)acrylic acid ester copolymer (A) is not limited to a triblock copolymer having an H-type structure, and may contain a block copolymer having another structure in addition to the triblock copolymer having an H-type structure. Examples of block copolymers having another structure include a block copolymer having a structure in which three first molecular chains are bonded via two second molecular chains.

[0073] The first molecular chain and the second molecular chain are bonded via an ester bond derived from the (meth)acryloyl group in the polyfunctional macromonomer (a2) (i.e., an ester bond corresponding to the ester bond in the formula (4)).

[0074] It is preferable that the first molecular chains are composed of a hard polymer and the second molecular chains are composed of a soft polymer, since this results in a cured product with high strength and high elongation. Here, the hard polymer refers to a polymer with a high glass transition temperature, and the soft polymer refers to a polymer with a low glass transition temperature.

[0075] When the first molecular chain is composed of a hard polymer, the monomer components constituting the first molecular chain (i.e., the monomer components excluding the polyfunctional macromonomer (a2)) preferably contain at least one monomer selected from the group consisting of methacrylic acid esters, isobornyl acrylate, dicyclopentenyl acrylate, and dicyclopentanyl acrylate. The proportion of the monomer in the total amount of the monomer components constituting the first molecular chain is preferably 60% by weight or more, more preferably 70% by weight or more. The upper limit may be 100% by weight.

[0076] Furthermore, when the second molecular chain is composed of a soft polymer, the second molecular chain may be a main chain skeleton of a polyoxyalkylene polymer or a (meth)acrylic acid ester polymer. However, in the latter case, the monomer component constituting the second molecular chain (the monomer component forming the main chain skeleton of (a2')) preferably contains an acrylic acid ester (excluding isobornyl acrylate, dicyclopentenyl acrylate, and dicyclopentanyl acrylate). The proportion of the acrylic acid ester among the monomer components constituting the second molecular chain is preferably 60% by weight or more, more preferably 70% by weight or more. The upper limit may be 100% by weight.

[0077] Since the first molecular chain is a molecular chain formed by reacting with a chain transfer agent (a3) ​​having a mercapto group, the first molecular chain may have at either end thereof a substituent derived from (a3) ​​that is -SR 8 In the formula, S represents a sulfur atom, and R 8 represents a hydrocarbon group which may have a reactive silicon group. Examples of the hydrocarbon group include an alkyl group, an aryl group, or an aralkyl group having 1 to 20 carbon atoms. The reactive silicon group is a reactive silicon group represented by the above-mentioned formula (1). R 8 Specific examples of the group include a reactive silicon group-containing methyl group, a reactive silicon group-containing propyl group, an n-dodecyl group, a tert-dodecyl group, and a lauryl group.

[0078] In order to improve the strength of the resulting cured product, the (meth)acrylic acid ester copolymer (A) may contain the -SR 8 The molar ratio of the main chain skeleton of the polyfunctional macromonomer (a2) to is preferably 0.03 or more, more preferably 0.05 or more, even more preferably 0.09 or more, and particularly preferably 0.1 or more. The upper limit of the molar ratio is not particularly limited, but is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.3 or less.

[0079] <Method for producing (meth)acrylic acid ester copolymer (A)> The (meth)acrylic acid ester copolymer (A) can be produced by polymerizing the above-mentioned monomer components. The polymerization method is not particularly limited, but may be a general free radical polymerization. According to this embodiment, even though it is free radical polymerization, it is possible to control the polymerization, produce the (meth)acrylic acid ester copolymer (A) which is a block copolymer, and further, make the molecular weight distribution of the copolymer relatively narrow.

[0080] Examples of polymerization initiators that can be used in the free radical polymerization include azo compounds such as 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], and 1,1'-azobis(cyclohexane-1-carbonitrile). Diacyl peroxides such as benzoyl peroxide, isobutyryl peroxide, isononanoyl peroxide, decanoyl peroxide, lauroyl peroxide, parachlorobenzoyl peroxide, and di(3,5,5-trimethylhexanoyl) peroxide; diisopropyl percarbonate, di-sec-butyl percarbonate, di-2-ethylhexyl percarbonate, di-1-methylheptyl percarbonate, and di-3-methoxybutyl percarbonate peroxydicarbonates such as tert-butyl perbenzoate, tert-butyl peracetate, tert-butyl per-2-ethylhexanoate, tert-butyl perisobutyrate, tert-butyl perpivalate, tert-butyl diperadipate, and cumyl perneodecanoate; ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; dialkyl peroxides such as di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, and 1,1-di(tert-hexylperoxy)-3,3,5-trimethylcyclohexane; hydroperoxides such as cumene hydroxyperoxide and tert-butyl hydroperoxide; and peroxides such as 1,1-di(tert-hexylperoxy)-3,3,5-trimethylcyclohexane. These polymerization initiators may be used alone or in combination of two or more.

[0081] Examples of solvents that can be used in the free radical polymerization include aromatic solvents such as toluene, xylene, styrene, ethylbenzene, paradichlorobenzene, di-2-ethylhexyl phthalate, and di-n-butyl phthalate; aliphatic hydrocarbon solvents such as hexane, heptane, octane, cyclohexane, and methylcyclohexane; carboxylic acid ester compounds such as butyl acetate, n-propyl acetate, and isopropyl acetate; ketone compounds such as methyl isobutyl ketone and methyl ethyl ketone; dialkyl carbonate compounds such as dimethyl carbonate and diethyl carbonate; and alcohol compounds such as n-propanol, 2-propanol, n-butanol, 2-butanol, isobutanol, tert-butanol, and amyl alcohol. Among these, alcohol compounds are preferred because they narrow the molecular weight distribution. Aromatic solvents are preferred because of their high dissolving power. Aliphatic hydrocarbon solvents are preferred because of their low odor. The molecular weight distribution of the (meth)acrylic acid ester copolymer (A) is affected by the amount of chain transfer agent (a3) ​​added and the solvent. When the amount of the chain transfer agent (a3) ​​added is 3% by weight or less, the type of solvent has a large effect. When it is desired to obtain a (meth)acrylic acid ester copolymer (A) having a narrow molecular weight distribution, it is preferable to use isobutanol as the solvent.

[0082] As described above, the (meth)acrylic acid ester copolymer (A) contains reactive silicon groups either by using a monomer (a4) having a reactive silicon group and a polymerizable unsaturated group, or by using a chain transfer agent (a3) ​​having a reactive silicon group in addition to a mercapto group. Both methods may be used in combination. By using a monomer (a4) having a reactive silicon group and a polymerizable unsaturated group, reactive silicon groups can be randomly introduced into the side chains of the molecular chain composed mainly of the (meth)acrylic acid ester (a1). Furthermore, by using a chain transfer agent (a3) ​​having a reactive silicon group in addition to a mercapto group, reactive silicon groups can be introduced into the terminals of the molecular chain composed mainly of the (meth)acrylic acid ester (a1).

[0083] However, in order to further introduce reactive silicon groups into the (meth)acrylic acid ester copolymer (A), the following method can also be used in combination. (iii) A method of copolymerizing a monomer having a reactive functional group (V group) with a (meth)acrylic acid ester (a1) or the like, and then reacting the resulting copolymer with a compound having a functional group reactive with the V group and a reactive silicon group. Specific examples include a method of copolymerizing 2-hydroxyethyl acrylate and then reacting with an isocyanate silane compound having a reactive silicon group, and a method of copolymerizing glycidyl acrylate and then reacting with an aminosilane compound having a reactive silicon group. (iv) A method of modifying the terminal functional groups of a (meth)acrylic acid ester copolymer synthesized by living radical polymerization to introduce reactive silicon groups. The (meth)acrylic acid ester copolymer obtained by living radical polymerization has terminal functional groups that can be easily introduced, and by modifying it, reactive silicon groups can be introduced at the terminals of the polymer.

[0084] Examples of the compound having a functional group reactive with the V group and a reactive silicon group used in the method (iii) include isocyanate silane compounds such as 3-isocyanatepropyldimethoxymethylsilane, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, isocyanatemethyldimethoxymethylsilane, isocyanatemethyltrimethoxysilane, and isocyanatemethyltriethoxysilane; 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and glycidoxymethylsilane; epoxy silane compounds such as ethyldimethoxymethylsilane, glycidoxymethyltrimethoxysilane, and glycidoxymethyltriethoxysilane; and aminosilane compounds such as 3-aminopropyldimethoxymethylsilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminomethyldimethoxymethylsilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, N-cyclohexylaminomethyldimethoxymethylsilane, N-cyclohexylaminomethyltrimethoxysilane, and N-cyclohexylaminomethyltriethoxysilane.

[0085] In method (iv), any modification reaction can be used. Examples include a method using a compound having a reactive silicon group and a reactive group capable of reacting with a terminal functional group obtained by living radical polymerization, and a method in which a double bond is introduced to the polymer terminal using a compound having a reactive group and a double bond capable of reacting with a terminal functional group, and then a reactive silicon group is introduced using a hydrosilylation reaction or the like.

[0086] <<Polyester (B) having reactive silicon groups>> The curable composition according to this embodiment contains a polyester (B) having a reactive silicon group, and thus can form a cured product with relatively high strength. Furthermore, the curable composition according to this embodiment can be used as a hot-melt curable composition that is solid at room temperature but becomes fluid when heated and melted, making it possible to apply it to a substrate. Hereinafter, the polyester (B) having a reactive silicon group will also be referred to as "polyester (B)" for short. The polyester (B) has a reactive silicon group represented by the above-mentioned formula (1). The reactive silicon group in the polyester (B) may be the same as or different from the reactive silicon group in the (meth)acrylic acid ester polymer (A).

[0087] Specific examples of the reactive silicon group contained in the polyester (B) include, but are not limited to, a trimethoxysilyl group, a triethoxysilyl group, a tris(2-propenyloxy)silyl group, a triacetoxysilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a dimethoxyethylsilyl group, a (chloromethyl)dimethoxysilyl group, a (chloromethyl)diethoxysilyl group, a (methoxymethyl)dimethoxysilyl group, a (methoxymethyl)diethoxysilyl group, an (N,N-diethylaminomethyl)dimethoxysilyl group, and an (N,N-diethylaminomethyl)diethoxysilyl group.

[0088] The polyester (B) preferably has one or more reactive silicon groups per molecule on average, and particularly preferably has a reactive silicon group at each of both ends of the main chain skeleton of the polyester.

[0089] The polyester (B) is preferably crystalline at room temperature, since this improves compatibility with the (meth)acrylic acid ester copolymer (A). The crystallinity can be evaluated by measuring the crystallinity of the polymer by X-ray diffraction (Ruland method) after cooling and solidifying it from a molten state at a cooling rate of 10°C / min (see, for example, "X-Ray Diffraction of Polymers," by L.E. Alexander, translated by Ichiro Sakurada, Kagaku Dojin, 1972, p. 125). The crystallinity of the polyester (B) is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more.

[0090] The main chain skeleton of the polyester (B) can be formed by a known method, for example, by condensation of a dibasic acid such as adipic acid with a diol, or by ring-opening polymerization of lactones. Examples of the dibasic acid include saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, and 1,20-eicosanedicarboxylic acid; maleic acid, fumaric acid, citraconic acid, mesaconic acid, 2-pentenedioic acid, methylenesuccinic acid, allylmalonic acid, isopropylidesuccinic acid, and 2,4-hexadecanedicarboxylic acid. Examples of suitable dibasic acids include unsaturated dicarboxylic acids such as enedioic acid and acetylenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, dibenzoic acid, 4,4'-oxydibenzoic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. These dibasic acids may be used alone or in combination of two or more. Among these, saturated aliphatic dicarboxylic acids are preferred, and succinic acid, suberic acid, adipic acid, sebacic acid, and 1,12-dodecanedicarboxylic acid are more preferred. When the polyester (B) is crystalline, 1,12-dodecanedicarboxylic acid, sebacic acid, adipic acid, and succinic acid are preferred because they increase the crystallinity of the polyester. Furthermore, polycarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid may be used in combination.

[0091] Examples of the diol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, 2-methyl-1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,5-heptanediol, 1,7-heptanediol, 3,4-heptanediol, 3,5-heptanediol, 1,2-octanedi ... Examples of the diol include octanediol, 1,8-octanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 1,12-dodecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclododecanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone diol, etc. These diols may be used alone or in combination of two or more. Also usable are diethylene glycol, triethylene glycol, tetraethylene glycol, 1,4-bis(β-hydroxyethoxy)benzene, 2,2-bis(4-hydroxyethoxyphenylpropane), and the like, in which some of the carbon atoms are substituted with oxygen atoms or aromatic rings. From the viewpoints of availability and workability, diols having 2 to 20 carbon atoms are preferred, and diols having 2 to 10 carbon atoms are more preferred. In particular, ethylene glycol, 1,6-hexanediol, and butanediol are suitable from the viewpoints of availability and improving the crystallinity of the polyester.

[0092] A polyester resin having hydroxyl groups at both ends of the main chain skeleton can be obtained by a conventional condensation polymerization reaction using the dibasic acid and the diol. The equivalent ratio (hydroxyl groups / carboxyl groups) of the hydroxyl groups of the diol to the carboxyl groups of the dibasic acid is preferably 1.02 to 1.5, more preferably 1.05 to 1.3. Specifically, the dibasic acid or its ester and the diol are polycondensed in the presence or absence of a catalyst at a temperature of about 150 to 250°C for about 1 to 50 hours to carry out esterification or transesterification.

[0093] In the polycondensation, a polyester resin having hydroxyl groups at both molecular terminals can be obtained by setting the number of moles of the diol charged to n+1 relative to the number of moles of the dibasic acid charged, n. Furthermore, the number average molecular weight of the polyester resin can be adjusted by adjusting the numbers n and n+1.

[0094] By introducing a reactive silicon group into the polyester resin having a hydroxyl group obtained by the polycondensation, a polyester (B) having a reactive silicon group can be obtained. The method for introducing reactive silicon groups into polyester resins is not particularly limited, and any known method may be used as appropriate, but for example, a method in which a polyester resin having a hydroxyl group is reacted with a reactive silicon group-containing compound having a hydrosilyl group, an isocyanate group, or a thiol group is preferred, and a method in which a reactive silicon group-containing compound having an isocyanate group is particularly preferred. Examples of reactive silicon group-containing compounds having an isocyanate group include 3-isocyanatepropyldimethoxymethylsilane, 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, isocyanatemethyldimethoxymethylsilane, isocyanatemethyltrimethoxysilane, and isocyanatemethyltriethoxysilane. When the compound is reacted with a polyester resin having a hydroxyl group, it is preferable to use a catalyst such as mercaptotin.

[0095] The number average molecular weight of the polyester (B) is not particularly limited, but from the viewpoint of the strength of the cured product and the usability as a hot-melt curable composition, the number average molecular weight is preferably 500 to 30,000, more preferably 1,000 to 20,000, even more preferably 2,000 to 10,000, and particularly preferably 2,000 to 4,500, in terms of polystyrene equivalent molecular weight measured by GPC.

[0096] The blending amount of the polyester (B) is preferably 1 to 80 parts by weight, more preferably 3 to 60 parts by weight, even more preferably 5 to 50 parts by weight, and particularly preferably 10 to 45 parts by weight, per 100 parts by weight of the (meth)acrylic acid ester-based copolymer (A), from the viewpoints of the strength of the cured product and the usability as a hot-melt curable composition.

[0097] <<Polyoxyalkylene polymer (C) having reactive silicon groups>> The curable composition according to one embodiment of the present invention may contain, in addition to the (meth)acrylic acid ester copolymer (A) having a reactive silicon group, a polyoxyalkylene polymer (C) having a reactive silicon group (hereinafter simply referred to as "polyoxyalkylene polymer (C)").

[0098] <Reactive silicon group> The polyoxyalkylene polymer (C) has a reactive silicon group represented by the above-mentioned formula (1). The reactive silicon group in the polyoxyalkylene polymer (C) may be the same as or different from the reactive silicon group in the (meth)acrylic acid ester copolymer (A).

[0099] Specific examples of the reactive silicon group contained in the polyoxyalkylene polymer (C) include, but are not limited to, a trimethoxysilyl group, a triethoxysilyl group, a tris(2-propenyloxy)silyl group, a triacetoxysilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a dimethoxyethylsilyl group, a (chloromethyl)dimethoxysilyl group, a (chloromethyl)diethoxysilyl group, a (methoxymethyl)dimethoxysilyl group, a (methoxymethyl)diethoxysilyl group, an (N,N-diethylaminomethyl)dimethoxysilyl group, and an (N,N-diethylaminomethyl)diethoxysilyl group. Among these, methyldimethoxysilyl group, trimethoxysilyl group, triethoxysilyl group, (chloromethyl)dimethoxysilyl group, (methoxymethyl)dimethoxysilyl group, (methoxymethyl)diethoxysilyl group, and (N,N-diethylaminomethyl)dimethoxysilyl group are preferred because they exhibit high activity and give cured products with good mechanical properties, and trimethoxysilyl group and triethoxysilyl group are more preferred, with trimethoxysilyl group being even more preferred, because they give cured products with high strength.

[0100] The polyoxyalkylene polymer (C) may have one or less reactive silicon groups on average at one terminal site, or may have more than one reactive silicon group on average at one terminal site. Here, having more than one reactive silicon group on average at one terminal site means that the polyoxyalkylene polymer (C) contains a polyoxyalkylene having two or more reactive silicon groups at one terminal site.

[0101] The terminal moiety having two or more reactive silicon groups can be represented, for example, by the following general formula (2).

[0102] [ka]

[0103] (In the formula, R 2 ,R 4 each independently represents a divalent bonding group having 1 to 6 carbon atoms, and R 2 ,R 4 The atom bonded to each carbon atom adjacent to R is either carbon, oxygen, or nitrogen. 3 ,R 5 each independently represents hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 1 to 10. R 1 , X and a are as described above for formula (1).

[0104] R 2 , R 4 R may be a divalent organic group having 1 to 6 carbon atoms, or may be a hydrocarbon group which may contain an oxygen atom. The hydrocarbon group preferably has 1 to 4 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms. 2 Specific examples of R include -CH2OCH2-, -CH2O-, and -CH2-, with -CH2OCH2- being preferred. 4 Specific examples of include -CH2- and -CH2CH2-, with -CH2- being preferred.

[0105] R 3 , R 5 The number of carbon atoms in the hydrocarbon group is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2. 3 , R 5 Specific examples of include a hydrogen atom, a methyl group, and an ethyl group, with a hydrogen atom and a methyl group being preferred, and a hydrogen atom being more preferred.

[0106] In a particularly preferred embodiment, the terminal moiety represented by general formula (2) is R 2 is -CH2OCH2- and R 4is -CH2- and R 3 and R 5 are each a hydrogen atom. n is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and even more preferably 1 or 2. However, n is not limited to a single value, and may be a mixture of multiple values.

[0107] The polyoxyalkylene polymer (C) may have an average of 1.0 or less reactive silicon groups at each terminal site, in which case the average number is preferably 0.4 or more, more preferably 0.5 or more, and even more preferably 0.6 or more.

[0108] The polyoxyalkylene polymer (C) may have an average of more than 1.0 reactive silicon groups at one terminal. In this case, the average number is preferably 1.1 or more, more preferably 1.5 or more, and even more preferably 2.0 or more. The average number is preferably 5 or less, more preferably 3 or less.

[0109] The polyoxyalkylene polymer (C) may have reactive silicon groups in positions other than the terminal positions, but it is preferable to have them only in the terminal positions, as this makes it easier to obtain a rubber-like cured product that has high elongation and a low elastic modulus.

[0110] From the viewpoint of the strength of the cured product, the average number of reactive silicon groups per molecule of the polyoxyalkylene polymer (C) is preferably more than 1.0, more preferably 1.2 or more, even more preferably 1.3 or more, even more preferably 1.5 or more, and particularly preferably 1.7 or more. The average number may be 2.0 or less, or more than 2.0. From the viewpoint of the elongation of the cured product, the average number is preferably 6.0 or less, more preferably 5.5 or less, and most preferably 5.0 or less.

[0111] <Main chain structure> The main chain skeleton of the polyoxyalkylene polymer (C) is not particularly limited, and examples thereof include polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer, polyoxypropylene-polyoxybutylene copolymer, etc. Among these, polyoxypropylene is preferred.

[0112] The main chain structure of the polyoxyalkylene polymer (C) may be linear or branched.

[0113] The number average molecular weight of the polyoxyalkylene polymer (C), in terms of polystyrene equivalent molecular weight measured by GPC, is preferably 3,000 or more and 100,000 or less, more preferably 3,000 or more and 50,000 or less, and particularly preferably 3,000 or more and 30,000 or less.

[0114] The molecular weight distribution (Mw / Mn) of the polyoxyalkylene polymer (C) is not particularly limited, but is preferably narrow. Specifically, it is preferably less than 2.0, more preferably 1.6 or less, even more preferably 1.5 or less, and particularly preferably 1.4 or less. From the viewpoint of improving various mechanical properties such as durability and elongation of the cured product, it is preferably 1.2 or less. The molecular weight distribution of the polyoxyalkylene polymer (C) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

[0115] <Method for synthesizing polyoxyalkylene polymer (C)> The method for synthesizing the polyoxyalkylene polymer (C) is not particularly limited. For example, first, an epoxy compound is polymerized with an initiator having a hydroxyl group to obtain a hydroxyl-terminated polymer. After reacting the hydroxyl groups of the polymer with an alkali metal salt (e.g., sodium methoxide), a halogenated hydrocarbon compound having a carbon-carbon unsaturated bond (e.g., allyl chloride) is reacted to introduce a carbon-carbon unsaturated bond at the polymer end. Next, a reactive silicon group-containing hydrosilane compound (e.g., dimethoxymethylsilane, trimethoxysilane) is reacted to obtain the reactive silicon group-containing polyoxyalkylene polymer (C).

[0116] A preferred embodiment of a polyoxyalkylene polymer (C) having an average of more than 1.0 reactive silicon group at one terminal site can be obtained as follows: As described above, the alkali metal salt is reacted with the hydroxyl groups of the hydroxyl-terminated polymer, followed by reaction with an epoxy compound having a carbon-carbon unsaturated bond (e.g., allyl glycidyl ether), and then reaction with a halogenated hydrocarbon compound having a carbon-carbon unsaturated bond (e.g., allyl chloride), thereby introducing two or more carbon-carbon unsaturated bonds at one terminal. This is followed by reaction with a reactive silicon group-containing hydrosilane compound.

[0117] It is also possible to introduce a reactive silicon group into the polymer by using a reactive silicon group-containing mercaptosilane instead of the reactive silicon group-containing hydrosilane compound.

[0118] The main chain of the polyoxyalkylene polymer (C) has an ester bond or a bond represented by the general formula (3): -NR 6 -C(=O)- (3) (In the formula, R 6 represents an organic group having 1 to 10 carbon atoms or a hydrogen atom).

[0119] A cured product obtained from a curable composition containing a polyoxyalkylene polymer (C) containing an ester bond or an amide segment may have high hardness and strength due to the action of hydrogen bonds, etc. However, a polyoxyalkylene polymer (C) containing an amide segment or the like may be cleaved by heat, etc. In addition, a curable composition containing a polyoxyalkylene polymer (C) containing an amide segment or the like tends to have a high viscosity. In consideration of the above advantages and disadvantages, a polyoxyalkylene containing an amide segment or the like may be used as the polyoxyalkylene polymer (C).

[0120] Examples of the amide segment represented by the general formula (3) include those formed by a reaction between an isocyanate group and a hydroxyl group, a reaction between an amino group and a carbonate, a reaction between an isocyanate group and an amino group, a reaction between an isocyanate group and a mercapto group, etc. In addition, those formed by a reaction between the amide segment containing an active hydrogen atom and an isocyanate group are also included in the amide segment represented by the general formula (3).

[0121] One example of a method for producing a polyoxyalkylene polymer (C) containing an amide segment is to react a polyoxyalkylene having an active hydrogen-containing group at its terminal with a polyisocyanate compound to synthesize a polymer having an isocyanate group at its terminal, and then, or simultaneously with the synthesis, to react a compound having both a functional group reactive with the isocyanate group (e.g., a hydroxyl group, a carboxyl group, a mercapto group, a primary amino group, or a secondary amino group) and a reactive silicon group. Another example is to react a polyoxyalkylene having an active hydrogen-containing group at its terminal with a reactive silicon group-containing isocyanate compound.

[0122] When the polyoxyalkylene polymer (C) contains an amide segment, the number (average number) of amide segments per molecule of the polyoxyalkylene polymer (C) is preferably 1 to 10, more preferably 1.5 to 5, and particularly preferably 2 to 3. If this number is less than 1, the curability may be insufficient, and conversely, if it is more than 10, the polyoxyalkylene polymer (C) may become highly viscous and difficult to handle. In order to reduce the viscosity of the curable composition and improve workability, it is preferable that the polyoxyalkylene polymer (C) does not contain an amide segment.

[0123] Methods of blending a (meth)acrylic acid ester copolymer (A) with a polyoxyalkylene polymer (C) have been proposed in JP-A Nos. 59-122541, 63-112642, 6-172631, and 11-116763, etc. 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.

[0124] When a polyoxyalkylene polymer (C) and a (meth)acrylic acid ester copolymer (A) are used in combination, the weight ratio of (C):(A) is preferably 95:5 to 50:50, i.e., the proportion of (C) is 50% by weight or more and 95% by weight or less. Within this range, a cured product exhibiting flexibility and high shear adhesive strength can be obtained. Furthermore, in order to achieve both high strength and flexibility, the ratio of (C):(A) is preferably 80:20 to 50:50, and more preferably 70:30 to 50:50.

[0125] <<Silanol condensation catalyst>> The silanol condensation catalyst is an optional component, but is preferably incorporated because it can promote the condensation reaction of the reactive silicon groups in the (meth)acrylic acid ester copolymer (A), the polyester (B), and the polyoxyalkylene polymer (C).

[0126] Examples of silanol condensation catalysts include organotin compounds, metal carboxylates, amine compounds, carboxylic acids, and alkoxy metals.

[0127] 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.

[0128] Specific examples of the metal carboxylate include tin carboxylate, bismuth carboxylate, titanium carboxylate, zirconium carboxylate, iron carboxylate, etc. The metal carboxylate can be a combination of the following carboxylic acids and various metals.

[0129] 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.

[0130] 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.

[0131] 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).

[0132] When a silanol condensation catalyst is used, the amount used is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, and even more preferably 0.01 to 10 parts by weight, per 100 parts by weight of the (meth)acrylic acid ester copolymer (A) (provided that, when a polyoxyalkylene polymer (C) is contained, the total amount of the (meth)acrylic acid ester copolymer (A) and the polyoxyalkylene polymer (C) is 100 parts by weight; the same applies hereinafter), from the viewpoint of promoting the condensation reaction of the reactive silicon groups.

[0133] <<Other additives>> In addition to the (meth)acrylic acid ester copolymer (A), the polyester (B), the polyoxyalkylene polymer (C), and the silanol condensation catalyst, the curable composition according to this embodiment may contain additives such as a plasticizer, a filler, an adhesion promoter, a dehydrating agent, a rheology control agent, an antioxidant, a light stabilizer, an ultraviolet absorber, and other resins.

[0134] Furthermore, various additives may be added to the curable composition according to this embodiment as needed for the purpose of adjusting the physical properties of the curable composition or the cured product. Examples of such additives include solvents, diluents, photocurable substances, oxygen-curable substances, surface property improvers, silicates, curability regulators, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, mildew inhibitors, flame retardants, and foaming agents.

[0135] <Plasticizer> A plasticizer can be blended into the curable composition. By blending a plasticizer, the viscosity of the curable composition can be reduced, making it easier to handle.

[0136] The plasticizer is not particularly limited, but examples thereof 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; non-phthalate ester compounds such as 1,2-cyclohexanedicarboxylic acid diisononyl ester; and fatty acids 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; phosphate ester compounds; trimellitic acid ester compounds; chlorinated paraffins; hydrocarbon oils such as alkyl diphenyls and partially hydrogenated terphenyls; process oils; epoxy plasticizers such as epoxidized soybean oil, epoxidized linseed oil, bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS), epoxy octyl stearate, epoxy butyl stearate, and epoxy benzyl stearate; alkyl sulfonic acid esters, etc.

[0137] As the plasticizer, a polymer plasticizer can also be used. Specific examples of the polymer plasticizer 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 polyether plasticizers 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, polychloroprene, etc. Among these, polymer plasticizers are preferred, polyether plasticizers are more preferred, and polypropylene glycol is particularly preferred. As the plasticizer, one type may be used alone, or two or more types may be used in combination.

[0138] The amount of the plasticizer to be added is preferably 5 to 150 parts by weight, more preferably 10 to 120 parts by weight, and particularly preferably 20 to 100 parts by weight, per 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0139] <Filler> The curable composition may contain a filler, which can improve the strength of the cured product.

[0140] Examples of fillers include heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, clay, talc, titanium oxide, fumed silica, precipitated silica, crystalline silica, fused silica, anhydrous silicic acid, hydrous silicic acid, alumina, carbon black, ferric oxide, fine aluminum powder, zinc oxide, activated zinc white, PVC powder, PMMA powder, glass fiber, and filaments. Organic or inorganic balloons may be added to reduce the weight (specific gravity) of the composition. Only one type of filler may be used, or two or more types may be used in combination.

[0141] The amount of the filler to be added is preferably 1 to 300 parts by weight, more preferably 10 to 250 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0142] <Adhesion promoter> The curable composition may contain an adhesion promoter. As the adhesion promoter, a silane coupling agent or a reaction product of a silane coupling agent can be added.

[0143] 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 adhesives include isocyanate group-containing silanes such as cyanatepropylmethyldimethoxysilane, α-isocyanatemethyltrimethoxysilane, and α-isocyanatemethyldimethoxymethylsilane; mercapto group-containing silanes such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane; and epoxy group-containing silanes such as γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Reaction products of various silane coupling agents can also be used. The adhesion promoter may be used alone or in combination with two or more.

[0144] The amount of the adhesion promoter to be added is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0145] <Dehydrating agent> A dehydrating agent can be added to the curable composition. Here, the dehydrating agent is preferably a compound capable of reacting with water, more preferably a silicon compound capable of reacting with water (excluding compounds that fall under the category of adhesion promoters), and particularly preferably a trialkoxysilane compound.

[0146] Specific examples of the dehydrating agent include, but are not limited to, vinyl group-containing silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, etc. Only one type of dehydrating agent may be used, or two or more types may be used.

[0147] The amount of the dehydrating agent to be added is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, and even more preferably 1 to 5 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0148] <Rheology control agent> If necessary, a rheology control agent may be added to the curable composition to prevent sagging and improve workability.

[0149] The rheology control agent is not particularly limited, but examples thereof include fatty acid amide waxes, hydrogenated castor oil derivatives, metal soaps such as calcium stearate, aluminum stearate, and barium stearate, dry silica, wet silica, etc. These rheology control agents may be used alone or in combination of two or more.

[0150] The amount of the rheology control agent to be added is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0151] <Antioxidants> The curable composition may contain an antioxidant (antiaging agent), which can improve the weather resistance of the cured product. Examples of antioxidants include hindered phenols, monophenols, bisphenols, and polyphenols. Specific examples of antioxidants are also described in JP-A-4-283259 and JP-A-9-194731. The amount of the antioxidant to be added is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0152] <Light stabilizer> The curable composition may contain a light stabilizer, which can prevent photo-oxidative deterioration 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. The amount of the light stabilizer to be added is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0153] <UV absorber> The curable composition may contain an ultraviolet absorber, which can improve the weather resistance of the surface of the cured product. Examples of ultraviolet absorbers include benzophenone-based, benzotriazole-based, salicylate-based, substituted tolyl-based, and metal chelate-based compounds, with benzotriazole-based compounds being particularly preferred, and examples include those commercially available under the names Tinuvin P, Tinuvin 213, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329, and Tinuvin 571 (all manufactured by BASF). The amount of the ultraviolet absorber to be added is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester copolymer (A).

[0154] <<Curable composition>> The curable composition according to one embodiment of the present invention can be prepared as a one-component composition in which all ingredients are mixed in advance and stored in a sealed container, and the composition is cured by moisture in the air after application. In this case, it is preferable to dehydrate and dry ingredients containing water before use, or to dehydrate them by reducing the pressure during mixing and kneading.

[0155] Furthermore, the curable composition according to one embodiment of the present invention is composed of a base agent containing a (meth)acrylic acid ester copolymer (A) and a polyester (B), and a curing agent containing components such as a silanol condensation catalyst, a filler, a plasticizer, and water, and can also be prepared as a two-component composition in which the base agent and the curing agent are mixed before use.

[0156] The method for preparing the curable composition according to one embodiment of the present invention is not particularly limited. For example, a common method may be used, such as blending the above components and kneading them at room temperature or under heat using a mixer, roll, kneader, or the like, or dissolving the above components in a small amount of an appropriate solvent and mixing them.

[0157] The curable composition according to one embodiment of the present invention exhibits good adhesion to various adherends, including plastics, metals, and composites. Furthermore, when used as an adhesive for nonpolar materials such as polypropylene or engineering plastics with rigid molecular chains such as polyphenylene sulfide, the adherends can be pre-surface-treated by a known method to enhance adhesion to these adherends and obtain stable adhesive strength. For example, surface treatment techniques such as sanding, flame treatment, corona discharge, arc discharge, and plasma treatment can be used. Plasma treatment is preferred because it causes minimal damage to the adherend and provides stable adhesion. These surface treatments are also effective for removing release agents remaining on the adherend surface after molding.

[0158] The cured product obtained by curing the curable composition according to one embodiment of the present invention has good adhesion to various adherends, and therefore the curable composition can be used as an adhesive, a sealant, or a pressure-sensitive adhesive. In particular, the curable composition according to one embodiment of the present invention is solid at room temperature, but becomes fluid when heated and melted, enabling it to be applied to a substrate, and therefore can be suitably used as a hot-melt curable composition.

[0159] In order to ensure workability when applying the curable composition according to one embodiment of the present invention to an adherend, it is preferable to reduce the viscosity by heating to a high temperature, and the temperature at that time is preferably about 70 to 180° C., more preferably 90 to 160° C., and even more preferably 100 to 150° C. The heating method is not particularly limited, and a conventionally known method can be used.

[0160] The curable composition according to one embodiment of the present invention can exhibit the desired physical properties by undergoing a long-term curing (aging) step after bonding the adherends. The conditions for the curing (aging) step are not particularly limited, but examples include a temperature of 5 to 90°C and a time of 24 hours to 1 week.

[0161] When the curable composition according to one embodiment of the present invention is used as a hot-melt curable composition, it can be used as a reactive hot-melt adhesive. This curable composition is suitable for use as an adhesive for joining panels of buses, trailers, trains, etc., as an adhesive for connecting displays and housings in smartphones, tablet devices, laptops, etc., and for joining dissimilar materials such as aluminum-steel, steel-composite materials, and aluminum-composite materials. When joining dissimilar materials, it is preferable to cover the joint with a sealer to prevent corrosion. Polymers having reactive silicon groups, as described herein, can be used as the sealer.

[0162] More specifically, the curable composition according to one embodiment of the present invention is preferably used as an adhesive for automobile parts such as vehicle panels, large vehicle parts such as trucks and buses, train parts, aircraft parts, ship parts, electrical parts, various machine parts, and the like. [Example]

[0163] The present invention will be specifically explained below by way of examples, but the present invention is not limited to these examples.

[0164] The number average molecular weight and weight average molecular weight in the examples are GPC molecular weights measured under the following conditions. Liquid delivery system: Tosoh HLC-8120GPC Column: Tosoh TSK-GEL H type Solvent: THF Molecular weight: Polystyrene equivalent Measurement temperature: 40℃

[0165] The end group-based molecular weight in the examples is a molecular weight calculated by determining the hydroxyl value according to the measurement method of JIS K 1557 and the iodine value according to the measurement method of JIS K 0070, taking into consideration the structure of the organic polymer (the degree of branching determined by the polymerization initiator used).

[0166] The average number of carbon-carbon unsaturated bonds introduced per terminal of the polymer shown in the examples was calculated by the following formula. (Average number of introductions) = [Unsaturated group concentration of polymer obtained from iodine value (mol / g) - Unsaturated group concentration of precursor polymer obtained from iodine value (mol / g)] / [Hydroxyl group concentration of precursor polymer obtained from hydroxyl value (mol / g)]

[0167] (Sulfur atom concentration) The sulfur atom concentration is a theoretical value calculated from the total amount of the monomer components used in the production of the (meth)acrylic acid ester copolymer (A) and the amount of the chain transfer agent (a3) ​​having a mercapto group.

[0168] (Synthesis Example 1) Using polyoxypropylene glycol with a number-average molecular weight of approximately 4,020 (terminal-based molecular weight of 2,980) as an initiator, propylene oxide was polymerized using a zinc hexacyanocobaltate glyme complex catalyst to obtain polyoxypropylene with hydroxyl groups at both ends, a number-average molecular weight of 21,100 (terminal-based molecular weight of 13,600), and a molecular weight distribution Mw / Mn of 1.21. To the resulting polyoxypropylene was added 60 ppm of U-360 (dibutyltin bis(isooctylmercaptopropionate, Nitto Kasei Co., Ltd.), and 0.93 equivalents of Karenz AOI (2-isocyanatoethyl acrylate, Showa Denko K.K.) relative to the hydroxyl groups of the polyoxypropylene were added dropwise. The reaction was carried out at 80°C for 1 hour in a nitrogen atmosphere containing 5.5% oxygen, yielding a polyfunctional macromonomer (a2-1), which is a polyoxyalkylene polymer having acryloyl groups at both ends (i.e., approximately two acryloyl groups per polymer molecule) and having a number-average molecular weight of 21,100 and a weight-average molecular weight of 24,930.

[0169] (Synthesis Example 2) A four-neck flask equipped with a stirrer was charged with 44.8 parts by weight of isobutanol, and the temperature was raised to 105° C. under a nitrogen atmosphere. A mixed solution prepared by dissolving 41.2 parts by weight of methyl methacrylate, 4.0 parts by weight of butyl acrylate, 4.0 parts by weight of stearyl methacrylate, 4.1 parts by weight of 3-methacryloxypropyltrimethoxysilane, 44.1 parts by weight of the polyfunctional macromonomer (a2-1) prepared in Synthesis Example 1, 2.6 parts by weight of 3-mercaptopropyltrimethoxysilane, and 0.9 parts by weight of 2,2′-azobis(2-methylbutyronitrile) in 28.5 parts by weight of isobutanol was added dropwise thereto over 5 hours. A mixed solution of 0.3 parts by weight of 2,2'-azobis(2-methylbutyronitrile) in 9.5 parts by weight of isobutanol was added and polymerized at 105°C for 2 hours to obtain an isobutanol solution (solids content 55%) of reactive silicon group-containing (meth)acrylic acid ester copolymer (A-1) with a number average molecular weight of 5,490 (GPC molecular weight). The polyfunctional macromonomer equivalent of the solid content of this solution was 0.021 mmol / g, the reactive silicon group equivalent was 0.30 mmol / g, and the sulfur atom concentration was 4,238 ppm.

[0170] (Synthesis Example 3) A four-neck flask equipped with a stirrer was charged with 100 parts by weight of HS 2H-500S (polyester polyol, manufactured by Toyokuni Oil Mills Co., Ltd.) and 30 ppm of Neostan U-360 (dibutyltin bis(isooctylthioglycolate), manufactured by Nitto Kasei Co., Ltd.), and the temperature was raised to 90°C under a nitrogen atmosphere. 7.5 parts by weight of 3-isocyanatopropyltrimethoxysilane was added dropwise thereto, and the mixture was allowed to react for 1 hour to obtain a polyester (B-1) having trimethoxysilyl groups at both ends.

[0171] Example 1 The polyester (B-1) obtained in Synthesis Example 3 was mixed with an isobutanol solution of the (meth)acrylic acid ester copolymer (A-1) obtained in Synthesis Example 2 so that 30 parts by weight of the polyester (B-1) obtained in Synthesis Example 3 was mixed with 100 parts by weight of the solid content, and the isobutanol was then heated to devolatilize, thereby obtaining a curable composition that was solid at room temperature.

[0172] (Tensile properties) 130 parts by weight of the resulting curable composition was heated to 130°C to melt it, and 2 parts by weight of KBM-603 (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.2 parts by weight of U-810 (dioctyltin dilaurate, manufactured by Nitto Kasei Co., Ltd.) were added and mixed. A sheet approximately 2 mm thick was prepared and aged for 7 days at 23°C and 50% RH. The resulting sheet was punched into a No. 1 dumbbell shape (JIS K 6251) and subjected to a tensile strength test at 23°C and 50% RH to measure the stress at 30% elongation (M30) and the strength at break (TB). Tensile properties were measured using a Shimadzu Autograph (AGS-X) at a pulling rate of 50 mm / min. The results are shown in Table 1.

[0173] (Comparative Example 1) A tensile strength test was carried out in the same manner as above using 100 parts by weight of the copolymer (A-1) obtained by heating and removing isobutanol from an isobutanol solution of the (meth)acrylic acid ester copolymer (A-1) obtained in Synthesis Example 2 without using polyester (B-1). The results are shown in Table 1.

[0174] [Table 1]

[0175] Table 1 shows that the curable composition of Example 1, which contains the reactive silicon group-containing (meth)acrylic acid ester copolymer (A) and the reactive silicon group-containing polyester (B), forms a cured product with higher tensile strength than the reactive silicon group-containing (meth)acrylic acid ester copolymer (A) of Comparative Example 1.

Claims

1. A (meth)acrylic acid ester copolymer (A) having a reactive silicon group represented by the following general formula (1), and The polyester (B) contains a reactive silicon group represented by the following general formula (1): The monomer components constituting the (meth)acrylic acid ester copolymer (A) are (Meth)acrylic acid ester (a1), a polymer (a2) having an average of 1.1 or more (meth)acryloyl groups per molecule; and a chain transfer agent (a3) ​​having a mercapto group, the monomer component further contains a monomer (a4) having a reactive silicon group and a polymerizable unsaturated group, and / or the chain transfer agent (a3) ​​having a mercapto group further contains a reactive silicon group; the (meth)acrylic acid ester copolymer (A) has a reactive silicon group equivalent of 0.2 mmol / g to 2.0 mmol / g; A curable composition, wherein the polyester (B) has, on average, one or more reactive silicon groups per molecule. -SiR １ ３－ａ X ａ (1) (In the formula, R １ represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms; X represents a hydroxyl group or a hydrolyzable group; and a is 2 or 3.

2. The curable composition according to claim 1, wherein the polymer (a2) is a polyoxyalkylene polymer (a2'') having an average of 1.1 or more (meth)acryloyl groups per molecule.

3. The curable composition according to claim 1, wherein the polymer (a2) is a (meth)acrylic acid ester-based polymer (a2') having an average of 1.1 or more (meth)acryloyl groups per molecule.

4. The curable composition according to any one of claims 1 to 3, wherein the molar ratio of the polymer (a2) to the chain transfer agent (a3) ​​having a mercapto group is 0.05 or more.

5. The curable composition according to any one of claims 1 to 4, wherein the polyester (B) is crystalline.

6. The curable composition according to any one of claims 1 to 5, which is a hot-melt curable composition.

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

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