Curable compositions, cured products, adhesives, and sealants

Abstract

The present invention relates to a curable composition that includes an oxyalkylene polymer A that has an average of 4–8 terminal groups per molecule and includes a reactive silicon group represented by (1) -SiXaR3-a (in which R is a C1–20 monovalent organic group that is not a hydrolyzable group, X is a halogen atom, a hydroxyl group, or a hydrolyzable group, and a is an integer from 1 to 3, it being possible for the Xs to be the same or different when a is 2 or 3, and it being possible for the Rs to be the same or different when a is 1), the terminal groups including the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen–containing group, and the molecular weight of the oxyalkylene polymer per terminal group as calculated by hydroxyl groups being 500–1,750.

Description

[Technical Field]

[0001] The present invention relates to a curable composition, a cured product, an adhesive, and a sealant. This application claims priority based on Japanese Patent Application No. 2021-113011, filed in Japan on July 7, 2021, and Japanese Patent Application No. 2022-033677, filed in Japan on March 4, 2022, and the contents thereof are incorporated herein by reference.

[0002] The present invention relates to a curable composition containing a polymer having a silicon group (hereinafter referred to as "reactive silicon group") which has a halogen atom, a hydroxyl group, or a hydrolyzable group bonded to a silicon atom and can be crosslinked by forming a siloxane bond. [Background technology]

[0003] Polymers having at least one reactive silicon group in a single molecule are known to have the property of crosslinking even at room temperature through the formation of siloxane bonds accompanied by hydrolysis reactions of the reactive silicon group due to moisture, etc., resulting in a rubbery cured product.

[0004] Among these polymers containing reactive silicon groups, those with a main chain skeleton consisting of oxyalkylene polymers, saturated hydrocarbon polymers, alkyl acrylate polymers, and alkyl methacrylate polymers are already produced industrially and are widely used in applications such as sealants, adhesives, and paints. When curable compositions containing these polymers containing reactive silicon groups are used as adhesives, the curability of the curable composition, as well as the elongation and adhesion to the substrate of the cured product, are important. High modulus and high tensile strength are also required as physical properties of the cured product.

[0005] To achieve high modulus and high tensile strength in cured products, it is known that increasing the number of reactive silicon groups in a single polymer molecule and raising the crosslinking density can be effective. Patent Document 1 discloses an oxyalkylene polymer having a number average molecular weight of 2,000 to 6,000 and containing an average of 2.1 to 5 reactive silicon groups per molecule. Specifically, in the examples, after converting the hydroxyl groups at the terminals of polyoxypropylene triol having a number average molecular weight of about 4,100 into allyl groups, the allyl groups were converted into dimethoxymethylsilyl groups, and a polymer having an average of 2.2 reactive silicon groups per molecule and a number average molecular weight of 4,100 was obtained. It is described that the polymer can provide a curable composition that gives a cured product with high hardness as a general building sealing material composition. Patent Document 2 discloses an oxyalkylene polymer having a number average molecular weight of 2,000 to 6,000 and containing 1.3 or more reactive silicon groups per molecule. Specifically, in the examples, after converting the hydroxyl groups at the terminals of polyoxypropylene triol having a hydroxyl value-converted molecular weight of about 3,000 into allyl groups, the allyl groups were converted into dimethoxymethylsilyl groups, and a polymer having an average of 2.2 reactive silicon groups per molecule and a number average molecular weight of 3,000 was obtained. It is described that by including the polymer, a curable composition with little residual tack can be obtained.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when a curable composition containing the polymer in Patent Document 1 or Patent Document 2 is used as an adhesive, the tensile strength of the cured product may be insufficient. The present invention has been made in view of the above circumstances, and an object thereof is to provide a curable composition that can obtain a cured product having excellent tensile strength. [Means for Solving the Problems]

[0008] The present invention is as follows [1] to

[14] . [1] A curable composition containing an oxyalkylene polymer A having an average of 4 to 8 terminal groups per molecule, having a reactive silicon group represented by the following formula (1), wherein the terminal group has the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group, and the hydroxyl-equivalent molecular weight of the following oxyalkylene polymer A per terminal group is 500 to 1,750. -SiX a R 3-a Formula (1) [In the formula, R is a monovalent organic group having 1 to 20 carbon atoms, representing an organic group other than a hydrolyzable group, X represents a halogen atom, a hydroxyl group or a hydrolyzable group. a is an integer of 1 to 3. When a is 2 or more, X may be the same or different from each other, and when a is 1, R may be the same or different from each other. ] [2] The curable composition according to [1], wherein the number-average molecular weight per terminal group of the polymer A is 600 to 2,750. [3] The curable composition according to [1] or [2], wherein the polymer A has an average of 0.5 to 1.0 reactive silicon groups represented by the formula (1) per terminal group. [4] The curable composition according to any one of [1] to [3], wherein the silylation rate of the polymer A is 50 to 100 mol%. [5] The curable composition according to any one of [1] to [4], wherein the content of the repeating unit based on the ethylene oxide monomer relative to the total mass of the polymer A is 0.1 to 30% by mass. [6] The curable composition according to any one of [1] to [5], further containing an oxyalkylene polymer B having an average of 2 to 3 terminal groups per molecule, having a reactive silicon group represented by the formula (1), and the terminal group having the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group. [7] The curable composition according to [6], wherein the polymer B has an average of 0.1 to 1.0 reactive silicon groups represented by formula (1) per terminal group. [8] The curable composition according to [6] or [7], wherein the hydroxyl group-based molecular weight of polymer B is 1,000 to 100,000. [9] The curable composition according to any one of [6] to [8], wherein the ratio of the mass of polymer A to the mass of polymer B is 5 / 95 to 95 / 5.

[10] A curable composition according to any one of [1] to [9], further comprising a linear oxyalkylene polymer C having an average of one terminal group in one molecule, the terminal group having a reactive silicon group represented by formula (1), and having a number average molecular weight of 2,000 or more.

[11] A curable composition according to any one of [1] to

[10] , further comprising a vinyl polymer D having an average of one or more reactive silicon groups represented by formula (1) in one molecule.

[12] A cured product of any one of the curable compositions described in [1] to

[11] . An adhesive comprising the cured product described in

[13]

[12] . A sealing material comprising the cured product described in

[14]

[12] . [Effects of the Invention]

[0009] The curable composition of the present invention can produce a cured product with excellent tensile strength. The cured product of the present invention has excellent tensile strength. [Modes for carrying out the invention]

[0010] The meanings and definitions of terms used in this specification are as follows: A numerical range represented by "~" means a range of numbers whose lower and upper limits are the numbers before and after the "~". The "units" that make up a polymer refer to atomic groups that are directly formed by the polymerization of monomers. The term "main chain" refers to the polymer chain formed by the polymerization of two or more monomers. In the oxyalkylene polymers described later, the "main chain" refers to the portion containing the initiator residue and repeating units based on alkylene oxide monomers (polyoxyalkylene chain). Oxyalkylene polymers are polymers consisting of a main chain and terminal groups. In oxyalkylene polymers, the "end group" refers to the group of oxygen atoms in the polyoxyalkylene chain that is closest to the end of the molecule. However, if the group of oxygen atoms includes an initiator residue, it is not considered an end group. An "active hydrogen-containing group" is at least one group selected from the group consisting of a hydroxyl group, carboxyl group, amino group, monovalent functional group obtained by removing one hydrogen atom from a primary amine, hydrazide group, and sulfanyl group, all of which are bonded to a carbon atom. "Active hydrogen" refers to hydrogen atoms based on the active hydrogen-containing group and hydrogen atoms based on the hydroxyl group of water. An "unsaturated group" refers to a monovalent group containing an unsaturated double bond. Unless otherwise specified, it is at least one group selected from the group consisting of vinyl, allyl, and isopropenyl groups. A "precursor polymer" refers to an oxyalkylene polymer obtained by polymerizing an alkylene oxide monomer onto the active hydrogen of an initiator, where the terminal group is a hydroxyl group.

[0011] The "silylation rate" is the ratio of the number of reactive silicon groups to the total number of reactive silicon groups, active hydrogen-containing groups, unsaturated groups, and isocyanate groups in the terminal groups of the oxyalkylene polymer. The value of the silylation rate can be measured by NMR analysis. Alternatively, it may be the ratio (mol%) of the number of silyl groups of the added silylating agent to the number of terminal groups when introducing the reactive silicon groups to the terminal groups of the oxyalkylene polymer using the silylating agent described later. However, in this case, a diisocyanate compound is used as the polyisocyanate compound in method (c) described later. A "silylation agent" refers to a compound having a functional group that reacts with an active hydrogen-containing group, an unsaturated group, or an isocyanate group, and a reactive silicon group.

[0012] The "number of terminal groups" is a value calculated by directly measuring the unsaturated group concentration by titration analysis based on the principle of the iodine value measurement method specified in JIS K 0070 (1992), after introducing unsaturated groups into the precursor polymer of the oxyalkylene polymer. The "number of terminal groups" in the oxyalkylene polymer is the same as the number of active hydrogens in the initiator and the number of terminal groups in the precursor polymer, as described later.

[0013] "Hydroxyl group-based molecular weight" refers to a value calculated in the case of a polymer containing repeating units based on alkylene oxide monomers, by calculating the hydroxyl value of the initiator or precursor polymer according to JIS K 1557 (2007) and then formulating it as "56,100 / (hydroxyl value) × (number of active hydrogens in the initiator, or number of terminal groups in the precursor polymer)".

[0014] The hydroxyl group-equivalent molecular weight of an oxyalkylene polymer per terminal group can be calculated by applying the hydroxyl value of the precursor polymer to the formula "56,100 / (hydroxyl value of the precursor polymer)". Alternatively, a calibration curve for hydroxyl group-equivalent molecular weight and Mn obtained by GPC measurement may be prepared in advance, and the hydroxyl group-equivalent molecular weight of the polymer can be estimated by applying the Mn measurement result of the polymer to be determined to this calibration curve, and then calculated by applying it to the formula "estimated hydroxyl group-equivalent molecular weight / estimated number of functional groups of the polymer". The number of functional groups of the polymer can be estimated by estimating the initiator by NMR, or by preparing a calibration curve for Mn obtained by GPC measurement and the viscosity of the polymer in advance for each polymer of each functional group, and then applying the measurement results of Mn and viscosity of the polymer to be determined to this calibration curve.

[0015] In this specification, the number-average molecular weight (Mn) and mass-average molecular weight (Mw) are polystyrene-equivalent molecular weights measured using GPC with tetrahydrofuran as the eluent, with a calibration curve created using polystyrene polymers of known molecular weight. The molecular weight distribution (Mw / Mn) is the ratio of Mw to Mn.

[0016] The curable composition of this embodiment contains an oxyalkylene polymer (hereinafter referred to as "polymer A") having an average of 4 to 8 terminal groups per molecule, a reactive silicon group represented by the following formula (1), wherein the terminal groups include the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group, and the hydroxyl group-equivalent molecular weight of the polymer per terminal group is 500 to 1,750. The curable composition has an average of 2 to 3 terminal groups per molecule and contains a reactive silicon group represented by the following formula (1), and the terminal groups may further contain an oxyalkylene polymer (hereinafter referred to as "polymer B") having the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group.

[0017] <Reactive silicon group> Reactive silicon groups have halogen atoms, hydroxyl groups, or hydrolyzable groups bonded to silicon atoms and can crosslink by forming siloxane bonds. The reaction that forms siloxane bonds is accelerated by a curing catalyst. The reactive silicon groups in polymer A are represented by the following formula (1). -SiX a R 3-a Formula (1)

[0018] In formula (1) above, R is a monovalent organic group having 1 to 20 carbon atoms, and represents an organic group other than a hydrolyzable group. R is preferably at least one selected from the group consisting of hydrocarbon groups having 1 to 20 carbon atoms and triorganosiloxy groups.

[0019] R is preferably at least one selected from the group consisting of alkyl groups, cycloalkyl groups, aryl groups, α-chloroalkyl groups, and triorganosiloxy groups. More preferably, R is at least one selected from the group consisting of linear or branched alkyl groups having 1 to 4 carbon atoms, cyclohexyl groups, phenyl groups, benzyl groups, α-chloromethyl groups, trimethylsiloxy groups, triethylsiloxy groups, and triphenylsiloxy groups. A methyl group or an ethyl group is preferred from the viewpoint of good curability of the polymer having a reactive silicon group and stability of the curable composition. An α-chloromethyl group is preferred from the viewpoint of a fast curing rate of the cured product. A methyl group is particularly preferred from the viewpoint of being readily available.

[0020] In formula (1) above, X represents a halogen atom, a hydroxyl group, or a hydrolyzable group. Examples of hydrolyzable groups include alkoxy groups, acyloxy groups, ketoximate groups, amino groups, amide groups, acid amide groups, aminooxy groups, sulfanyl groups, and alkenyloxy groups. Alkoxy groups are preferred because they are mildly hydrolyzable and easy to handle. Methoxy, ethoxy, and isopropoxy groups are preferred alkoxy groups, with methoxy or ethoxy groups being more preferred. When the alkoxy group is a methoxy or ethoxy group, siloxane bonds are quickly formed, making it easier to form a crosslinked structure in the cured product, which tends to result in good physical properties of the cured product.

[0021] In formula (1) above, a is an integer between 1 and 3. When a is 1, R may be the same or different from each other. When a is 2 or greater, X may be the same or different from each other. Since the cured product tends to have a high modulus and excellent elongation and tensile strength, a is preferably 2 or 3, and more preferably 2.

[0022] Examples of the reactive silicon group represented by formula (1) include trimethoxysilyl group, triethoxysilyl group, triisopropoxysilyl group, tris(2-propenyloxy)silyl group, triacetoxysilyl group, dimethoxymethylsilyl group, diethoxymethylsilyl group, dimethoxyethylsilyl group, methyldiisopropoxysilyl group, (α-chloromethyl)dimethoxysilyl group, and (α-chloromethyl)diethoxysilyl group. From the viewpoint of high activity and good curability, trimethoxysilyl group, triethoxysilyl group, dimethoxymethylsilyl group, and diethoxymethylsilyl group are preferred, and dimethoxymethylsilyl group is more preferred.

[0023] <Polymer A> Polymer A is an oxyalkylene polymer having an average of 4 to 8 terminal groups per molecule, each containing a reactive silicon group represented by formula (1), wherein the terminal groups are the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group, and the hydroxyl group-equivalent molecular weight of the oxyalkylene polymer per terminal group is 500 to 1,750. Polymer A in the curable composition of this embodiment may be of two or more types.

[0024] The main chain of polymer A is a polymerization chain consisting of an initiator residue and an oxyalkylene chain containing repeating units based on one or more alkylene oxide monomers (hereinafter, repeating units based on monomers will simply be referred to as "monomer units," for example, repeating units based on alkylene oxide monomers will be referred to as "alkylene oxide units"). If the polymerization chain has two or more types of alkylene oxide units, these alkylene oxide units may form block polymers or random polymers. Examples of oxyalkylene chains include polymer chains having ethylene oxide units, polymer chains having propylene oxide units, polymer chains having ethylene oxide units and propylene oxide units, polymer chains consisting of ethylene oxide units, polymer chains consisting of propylene oxide units, polymer chains consisting of butylene oxide units, polymer chains consisting of tetramethylene oxide units, polymer chains consisting of ethylene oxide units and propylene oxide units, and polymer chains consisting of propylene oxide units and butylene oxide units. Polymer chains having ethylene oxide units, polymer chains having propylene oxide units, polymer chains having ethylene oxide units and propylene oxide units, polymer chains consisting of propylene oxide units, and polymer chains consisting of ethylene oxide units and propylene oxide units are preferred, with polymer chains consisting of propylene oxide units being particularly preferred. Furthermore, when polymer A has polymer chains containing ethylene oxide units, the content of ethylene oxide units relative to the total mass of polymer A is preferably 0.1 to 30% by mass, and more preferably 10 to 20% by mass. When the ethylene oxide unit content in polymer A is above the lower limit, it is preferable that the curing process is faster, and when it is below the upper limit, it is preferable that the viscosity can be easily reduced. When polymer A has a polymerization chain having ethylene oxide units and propylene oxide units, or a polymerization chain consisting of ethylene oxide units and propylene oxide units, the ethylene oxide unit content relative to the total mass of polymer A is preferably 0.1 to 30% by mass, and more preferably 10 to 20% by mass. When the ethylene oxide unit content in polymer A is above the lower limit, it is preferable that the curing process is faster, and when it is below the upper limit, it is preferable that the viscosity can be easily reduced. When polymer A has a polymerization chain having ethylene oxide units and propylene oxide units, the propylene oxide unit content relative to the total mass of polymer A is preferably 50 to 99.9% by mass, and more preferably 70 to 90% by mass.

[0025] Polymer A has an average of 4 to 8 end groups per molecule. It is more preferable to have an average of 4 to 6 end groups per molecule because the cured product has higher tensile strength, modulus, and elongation. The end groups of polymer A have one of the reactive silicon group, active hydrogen-containing group, unsaturated group, and isocyanate group represented by formula (1), and it is preferable that they have one or more groups selected from the group consisting of the reactive silicon group, hydroxyl group bonded to a carbon atom, unsaturated group, and isocyanate group represented by formula (1). Each end group may be the same or different from the others. Preferred active hydrogen-containing groups include hydroxyl groups, amino groups, and monovalent functional groups obtained by removing a hydrogen atom from a primary amine, with hydroxyl groups bonded to a carbon atom being more preferred.

[0026] Polymer A preferably has an average of 0.5 to 1.0 reactive silicon groups represented by formula (1) per terminal group, and more preferably 0.60 to 0.97. If the number is above the lower limit of the above range, the tensile strength of the cured product is superior and the modulus is higher.

[0027] The hydroxyl group-equivalent molecular weight of polymer A per terminal group is 500 to 1,750, more preferably 600 to 1,700, even more preferably 700 to 1,650, and most preferably 700 to 1,500. If it is above the lower limit of the above range, the elongation properties of the cured product are good. If it is below the upper limit of the above range, the tensile strength of the cured product is better and the modulus is higher. The hydroxyl group-based molecular weight of polymer A is preferably 2,000 to 14,000, more preferably 2,500 to 13,000, and most preferably 2,500 to 12,000. If it is above the lower limit of the above range, the elongation properties of the cured product will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher. The molecular weight distribution of polymer A is preferably 1.8 or less. A smaller molecular weight distribution is preferable because it is easier to obtain good elongation properties, more preferably 1.0 to 1.6, even more preferably 1.02 to 1.5, and particularly preferably 1.04 to 1.4.

[0028] The Mn value of polymer A is preferably 2,400 to 20,000, more preferably 3,000 to 19,000, even more preferably 3,000 to 18,000, and particularly preferably 3,500 to 11,000. If the Mn value is above the lower limit of the above range, the elongation properties of the cured product will be better. If the Mn value is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher. The Mn of polymer A per terminal group, obtained by dividing the Mn of polymer A by the number of terminal groups of polymer A, is preferably 600 to 3,000, more preferably 600 to 2,750, even more preferably 650 to 2,750, and particularly preferably 700 to 2,100. If it is above the lower limit of the above range, the elongation properties of the cured product will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher. In one aspect of the present invention, it is preferable that polymer A has a hydroxyl group-equivalent molecular weight of 500 to 1,750 per terminal group, and a Mn content of 600 to 2,750 per terminal group.

[0029] Examples of methods for producing polymer A include the following methods (a) to (c). Method (a): Convert the hydroxyl group of the precursor polymer to an alkenyloxy group, and then convert the unsaturated group of the alkenyloxy group to a reactive silicon group represented by formula (1) -SiX a R 3-a A method for converting an alkenyloxy group to a group having a reactive silicon group represented by the above formula (1) by reacting it with a silylating agent that can introduce the group. Method (b): A method of converting a hydroxyl group of a precursor polymer into a group having a reactive silicon group represented by formula (1) by reacting the hydroxyl group with a silylating agent having a functional group that can react with the hydroxyl group and a reactive silicon group represented by formula (1) above. Method (c): A method of converting the hydroxyl groups of a precursor polymer into groups having an isocyanate group, and then reacting them with a silylating agent having a functional group that can react with an isocyanate group and a reactive silicon group represented by formula (1) above, thereby converting the hydroxyl groups into groups having a reactive silicon group represented by formula 1 above.

[0030] Examples of the silylating agent used in method (a) include compounds having both a group capable of reacting with an unsaturated group to form a bond (for example, a sulfanyl group) and a reactive silicon group represented by the above formula (1), and hydrosilane compounds (for example, HSiX a R 3-a , where X, R, and a are the same as those in the above formula (1)). Specifically, for example, dimethoxymethylsilane, diethoxymethylsilane, dimethoxyethylsilane, methyldiisopropoxysilane, (α-chloromethyl)dimethoxysilane, (α-chloromethyl)diethoxysilane, trimethoxysilane, triethoxysilane, triisopropoxysilane, tris(2-propenyloxy)silane, triacetoxysilane, 3-mercaptopropyltrimethoxysilane can be exemplified. From the viewpoint of high activity and good curability, trimethoxysilane, dimethoxymethylsilane, and diethoxymethylsilane are preferred, and dimethoxymethylsilane is more preferred.

[0031] As the silylating agent used in method (b), an isocyanate silane compound represented by the following formula (2) is preferred. OCN-(CH2) n -SiX a R 3-a ···Formula (2) -SiX a R 3-a in the above formula (2) is the same as that in the above formula (1). n is an integer of 1 to 8, preferably 1 to 3. By the reaction of the hydroxyl group of the prepolymer with the above isocyanate silane compound, the hydroxyl group of the prepolymer is converted to a terminal group having a urethane bond (-O-C(=O)NH-) and -SiX n -SiX a R 3-a represented by a R 3-a . Examples of isocyanate silane compounds include 3-isocyanate propyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, isocyanate methyltrimethoxysilane, isocyanate methyltriethoxysilane, 3-isocyanate propylmethyldimethoxysilane, 3-isocyanate propylmethyldiethoxysilane, isocyanate methylmethyldimethoxysilane, and isocyanate methylmethyldiethoxysilane. As isocyanate silane compounds, 3-isocyanate propyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, 3-isocyanate propylmethyldimethoxysilane, isocyanate methylmethyldimethoxysilane, and isocyanate methyltrimethoxysilane are preferred due to their reactivity with the precursor polymer and ease of handling. This reaction may be carried out in the presence of a urethane catalyst. The urethane catalyst is not particularly limited, and any known urethane catalyst can be used as appropriate. Examples include organotin compounds such as dibutyltin dilaurate and dioctyltin dilaurate, metal catalysts such as bismuth compounds, and base catalysts such as organic amines. The reaction temperature is preferably 20 to 200°C, and more preferably 50 to 150°C. Furthermore, the urethane reaction is preferably carried out under an inert gas atmosphere. Nitrogen is preferred as the inert gas.

[0032] In method (c), a polyisocyanate compound is reacted with the hydroxyl group of the precursor polymer to convert the hydroxyl group into a monovalent organic group containing an isocyanate group having a urethane bond (-OC(=O)NH-) at the terminal end that connects to the precursor polymer (hereinafter also referred to as the "isocyanate-containing group"). Then, the isocyanate-containing group is reacted with a silylation agent having a functional group that can react with an isocyanate group and a reactive silicon group represented by the above formula (1) to obtain a terminal group that is a monovalent organic group having one or more urethane bonds (-OC(=O)NH-) and a silylation agent residue that has reacted with an isocyanate group (hereinafter also referred to as the "urethane-bonded and reactive silicon group-containing group"). Hereinafter, the polyisocyanate compound described above will be a diisocyanate compound represented by formula (3) below, and the silylation agent having a functional group that can react with an isocyanate group and a reactive silicon group represented by formula (1) above will be a compound represented by formula (4) below, and method (c) will be described below, but will not be limited thereto.

[0033] OCN-R 1 -NCO...Formula (3) R in equation (3) above 1 This indicates a divalent organic group.

[0034] WR 2 -SiX a R 3-a ...Equation (4) In formula (4) above, W is a functional group that can react with a monovalent isocyanate group (a group having one or more active hydrogen atoms), R 2 -SiX is a divalent organic group. a R 3-a This is the same as equation (1) above.

[0035] When the hydroxyl group of the precursor polymer is reacted with the polyisocyanate compound represented by formula (3) above, the isocyanate-containing group is -OC(=O)NH-R 1 The group is represented by -NCO. When the above isocyanate-containing group is reacted with the silylating agent represented by formula (4) above, the above urethane bond and reactive silicon group-containing group become -OC(=O)NH-R 1 -NHC(=O)-W'-R 2 -SiX a R 3-a (However, W' is a divalent group obtained by removing one active hydrogen atom from W.) This results in a group represented by -OC(=O)NH-R 1 -NHC(=O)-OR 2 -SiX a R 3-a This is a group represented by [the formula shown]. In this case, the urethane bond and the reactive silicon group-containing group have two urethane bonds. R 1Preferably, the group is a divalent organic group having 2 to 20 carbon atoms, and examples include alkylene groups, cycloalkylene groups, bicycloalkylene groups, monocyclic or polycyclic divalent aromatic hydrocarbon groups, divalent groups obtained by removing two hydrogen atoms from a cycloalkane having an alkyl group as a substituent, divalent groups obtained by removing two hydrogen atoms from an aromatic hydrocarbon having an alkyl group as a substituent, a divalent group obtained by removing two hydrogen atoms from two or more cycloalkanes that may have alkyl groups as substituents and are bonded via an alkylene group, a divalent group obtained by removing two hydrogen atoms from two or more aromatic hydrocarbons that may have alkyl groups as substituents and are bonded via an alkylene group. Examples of diisocyanate compounds represented by formula (3) above and other polyisocyanate compounds include aromatic polyisocyanates, non-yellowing modified aromatic polyisocyanates (compounds that do not have isocyanate groups directly bonded to carbon atoms constituting the aromatic ring), aliphatic polyisocyanates and alicyclic polyisocyanates, as well as urethane modified products, biuret modified products, allophanate modified products, carbodiimide modified products and isocyanurate modified products obtained from the above polyisocyanates. Examples of aromatic polyisocyanates include naphthalene-1,5-diisocyanate, polyphenylene-polymethylene-polyisocyanate, 4,4'-diphenylmethane-diisocyanate, 2,4-tolylene-diisocyanate, and 2,6-tolylene-diisocyanate. Examples of non-yellowing aromatic polyisocyanates include xylylene diisocyanate and tetramethylxylylene diisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, and 2,4,4-trimethyl-hexamethylene diisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate and 4,4'-methylenebis(cyclohexyl isocyanate). The polyisocyanate compound is preferably one having two isocyanate groups, and is preferably hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, or 2,6-tolylene diisocyanate, with tolylene diisocyanate being more preferred because it is easier to obtain the tensile strength of the cured product. One polyisocyanate compound may be used, or two or more may be used in combination.

[0036] Functional groups that can react with the isocyanate group represented by formula (4) and -SiX a R 3-a In silylating agents having R 2 Preferably, the group is a divalent organic group having 1 to 20 carbon atoms; more preferably, a group obtained by removing two hydrogen atoms from an aromatic hydrocarbon having 6 to 10 carbon atoms; more preferably, a group obtained by removing two hydrogen atoms from an aromatic hydrocarbon having 6 to 10 carbon atoms substituted with an alkyl group having 1 to 4 carbon atoms; more preferably, a group obtained by removing two hydrogen atoms from a cyclic hydrocarbon having 3 to 10 carbon atoms; more preferably, a group obtained by removing two hydrogen atoms from a linear hydrocarbon having 1 to 12 carbon atoms; even more preferably, a group obtained by removing two hydrogen atoms from a linear hydrocarbon having 1 to 8 carbon atoms; and particularly preferably, a group obtained by removing two hydrogen atoms from a linear hydrocarbon having 1 to 6 carbon atoms. W is preferably a group having one or two active hydrogen atoms, selected from a hydroxyl group, a carboxyl group, a sulfanyl group, an amino group, or an amino group in which one hydrogen atom is substituted with an alkyl group having 1 to 6 carbon atoms. Hydroxyl groups, sulfanyl groups, amino groups, methylamino groups, ethylamino groups, and butylamino groups are preferred, and hydroxyl groups, amino groups, methylamino groups, ethylamino groups, and butylamino groups are more preferred.

[0037] The number of reactive silicon groups introduced into polymer A is preferably 0.5 to 1.0 on average per terminal group, as described above. More preferably, 0.60 to 0.97 groups are introduced, as this allows for a good balance between a high modulus and good elongation properties in the cured product.

[0038] The precursor polymer is an oxyalkylene polymer obtained by ring-opening addition polymerization of an alkylene oxide monomer to the active hydrogen of an initiator having an active hydrogen-containing group, in the presence of a ring-opening polymerization catalyst. The number of active hydrogens in the initiator, the number of terminal groups in the precursor polymer, and the number of terminal groups in polymer A are the same. The precursor polymer is preferably a polymer whose terminal groups are hydroxyl groups, obtained by ring-opening addition polymerization of an alkylene oxide monomer to an initiator having a hydroxyl group. The initiator is preferably one having 4 to 8 active hydrogen atoms, and more preferably one having 4 to 6. The active hydrogen-containing group in the initiator is preferably a hydroxyl group. More than one initiator may be used in combination. When more than one initiator is used, the molar average of the number of active hydrogen atoms in those initiators should be between 4 and 8. Examples of initiators having 4 to 8 active hydrogen atoms include pentaerythritol, sucrose, sorbitol, dipentaerythritol, trehalose, diglycerin, and ethylenediamine, with pentaerythritol and sorbitol being preferred from the viewpoint of tensile strength of the cured product.

[0039] When using alkylene oxide monomers as initiators for ring-opening addition polymerization, conventionally known catalysts can be used as ring-opening polymerization catalysts. Examples include alkaline catalysts such as KOH, metal compound-porphyrin complex catalysts such as complexes obtained by reacting organoaluminum compounds with porphyrins, complex metal cyanide catalysts, and catalysts consisting of phosphazene compounds. A composite metal cyanide complex catalyst is preferred because it can narrow the molecular weight distribution of polymer A, making it easier to obtain a curable composition with low viscosity. The composite metal cyanide complex catalyst can be a conventionally known compound, and the method for producing the polymer using the composite metal cyanide complex can also be a known method. For example, compounds and production methods disclosed in International Publication No. 2003 / 062301, International Publication No. 2004 / 067633, Japanese Patent Publication No. 2004-269776, Japanese Patent Publication No. 2005-15786, International Publication No. 2013 / 065802, and Japanese Patent Publication No. 2015-010162 can be used. The hydroxyl group-based molecular weight of polymer A per terminal group can be calculated from the hydroxyl group-based molecular weight of the precursor polymer before the introduction of the reactive silicon group by methods (a) to (c) described above. In the precursor polymer of polymer A, the hydroxyl group-equivalent molecular weight of the precursor polymer per terminal group is preferably 500 to 1,750, more preferably 600 to 1,700, even more preferably 700 to 1,650, and most preferably 700 to 1,500. If it is above the lower limit of the above range, the elongation properties of the cured product will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher. The hydroxyl group-based molecular weight of the precursor polymer is preferably 2,000 to 14,000, more preferably 2,500 to 13,000, and even more preferably 2,500 to 12,000. If it is above the lower limit of the above range, the elongation properties of the cured product will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher.

[0040] The silylation rate of polymer A is preferably 50 to 100 mol%, and more preferably 60 to 97 mol%. When the silylation rate is above the lower limit of the above range, the cured product exhibits excellent tensile strength and high modulus. If the curable composition contains two or more types of polymer A, it is sufficient that the average silylation rate of the entire polymer A is within the above range.

[0041] <Polymer B> Polymer B has an average of 2 to 3 terminal groups per molecule and contains a reactive silicon group represented by formula (1), wherein the terminal groups are an oxyalkylene polymer having a reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group. There may be two or more types of polymer B in the curable composition of this embodiment. The example of the main chain of polymer B is the same as the example of the main chain of polymer A.

[0042] The reactive silicon group described above is the same as that in formula (1), and the preferred embodiment is also the same.

[0043] A curable composition containing polymer B having an average of 2 to 3 terminal groups per molecule is preferred because it maintains high modulus, elongation properties, and tensile strength, and polymer B having 3 terminal groups is more preferred. The terminal groups of polymer B have one of the reactive silicon group, active hydrogen-containing group, unsaturated group, and isocyanate group represented by formula (1), and preferably one or more groups selected from the group consisting of the reactive silicon group, hydroxyl group bonded to a carbon atom, unsaturated group, and isocyanate group represented by formula (1). The terminal groups may be the same or different from each other.

[0044] Polymer B preferably has an average of 0.1 to 1.0 reactive silicon groups represented by formula (1) per terminal group, and is more preferably 0.30 to 0.97, and particularly preferably 0.60 to 0.97, as this tends to result in a cured product with a high modulus and excellent elongation and tensile strength.

[0045] The hydroxyl group-based molecular weight of polymer B is preferably 1,000 to 100,000, more preferably 2,000 to 100,000, even more preferably 3,000 to 100,000, and particularly preferably 8,000 to 100,000. If it is above the lower limit of the above range, the elongation properties of the cured product will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher. The molecular weight distribution of polymer B is preferably 1.8 or less. A smaller molecular weight distribution is preferable because it is easier to obtain good elongation properties, more preferably 1.0 to 1.5, even more preferably 1.02 to 1.4, and particularly preferably 1.04 to 1.3.

[0046] The Mn value of polymer B is preferably 3,000 to 90,000, more preferably 3,500 to 90,000, even more preferably 4,000 to 90,000, and particularly preferably 12,000 to 90,000. If it is above the lower limit of the above range, the elongation properties of the cured product will be good. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher.

[0047] Polymer B is preferably obtained by introducing an average of 0.1 to 1.0 reactive silicon groups represented by formula (1) per terminal group to the terminal groups of the precursor polymer. A higher modulus in the cured product allows for both elongation properties and tensile strength, so a polymer obtained by introducing 0.30 to 0.97 groups is more preferable, and a polymer obtained by introducing 0.60 to 0.97 groups is particularly preferable. Polymer B, which has 2 to 3 terminal groups in one molecule, can be produced using an initiator that has 2 to 3 active hydrogen atoms. Compounds having 2 to 3 active hydrogen atoms are preferred if they have 2 to 3 hydroxyl groups, and compounds having 3 hydroxyl groups are more preferred because they can maintain elongation properties and tensile strength at a higher modulus. Two or more initiators may be used in combination. Examples of compounds having two hydroxyl groups include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, triethylene glycol, tripylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, and low molecular weight polyoxypropylene glycol. Compounds having three hydroxyl groups include glycerin, trimethylolpropane, and trimethylolethane. As compounds having 2 to 3 hydroxyl groups, propylene glycol, low molecular weight polyoxypropylene glycol, and glycerin are preferred because the cured product tends to have a high modulus and excellent elongation and tensile strength.

[0048] The precursor polymer of polymer B can be produced in the same manner as the precursor polymer of polymer A, except that a compound having 2 to 3 active hydrogens is used as the initiator. A precursor polymer with hydroxyl groups at the end is preferred, which is produced by ring-opening addition polymerization of an alkylene oxide monomer to an initiator having a hydroxyl group. Polymer B can be produced in the same manner as polymer A, except that a precursor polymer of polymer B is used. That is, the production methods described in methods (a) to (c) above can be applied to polymer B. The hydroxyl group-based molecular weight of the precursor polymer in polymer B is preferably 1,000 to 100,000, more preferably 2,000 to 100,000, even more preferably 3,000 to 100,000, and particularly preferably 8,000 to 100,000. If it is above the lower limit of the above range, the elongation properties of the cured product will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher.

[0049] The silylation rate of polymer B is preferably 10 to 100 mol%, more preferably 30 to 97 mol%, and even more preferably 60 to 97 mol%. When the silylation rate of polymer B is above the lower limit of the above range, the cured product exhibits excellent tensile strength and high modulus. If the curable composition contains two or more types of polymer B, it is sufficient that the average silylation rate of the entire polymer B is within the above range.

[0050] <Polymer C> The curable composition of this embodiment may contain a linear oxyalkylene polymer (hereinafter referred to as "polymer C") having an average of one terminal group per molecule, the terminal group having a reactive silicon group represented by formula (1), and a number-average molecular weight of 2,000 or more. One molecular end of polymer C has a structure derived from an initiator residue, and the other molecular end has a structure derived from the terminal group. The curable composition of this embodiment may contain two or more types of polymer C. Polymer C acts as a reactive plasticizer, making the viscosity of the curable composition even lower. The example of the main chain of polymer C is the same as the example of the main chain of polymer A.

[0051] Polymer C preferably has an average of more than 0 and 1.0 reactive silicon groups represented by formula (1) per terminal group, more preferably more than 0.5 and 1.0, even more preferably 0.51 to 0.97, and particularly preferably 0.52 to 0.95.

[0052] The hydroxyl group-based molecular weight of polymer C is preferably 2,000 to 15,000, more preferably 2,200 to 12,000, and even more preferably 2,500 to 10,000. If it is above the lower limit of the above range, the tensile strength of the cured product is superior and the modulus is higher. If it is below the upper limit of the above range, the viscosity is suppressed and the workability is improved. The manganese (Mn) of polymer C is preferably 2,000 to 15,000, more preferably 2,200 to 12,000, and even more preferably 2,500 to 10,000. If it is above the lower limit of the above range, the tensile strength of the cured product is superior and the modulus is higher. If it is below the upper limit of the above range, the viscosity is suppressed and the workability is improved. The molecular weight distribution of polymer C is preferably 1.8 or less. From the viewpoint of viscosity reduction, a smaller molecular weight distribution is preferable, more preferably 1.0 to 1.6, even more preferably 1.02 to 1.5, and particularly preferably 1.04 to 1.4.

[0053] Polymer C is obtained by introducing the reactive silicon groups to a precursor polymer having one terminal group which is an active hydrogen-containing group, on average at a rate of more than 0 and less than 1.0 per terminal group. R is an initiator residue that is one of the molecular ends of polymer C. 10 -O-(R 10 (A monovalent hydrocarbon group is preferred.) 10 Preferably, the alkyl group is a branched or linear alkyl group having 1 to 20 carbon atoms, more preferably a branched or linear alkyl group having 1 to 10 carbon atoms, even more preferably a branched or linear alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, or t-butyl group.

[0054] The precursor polymer of polymer C can be produced in the same manner as the precursor polymer of polymer A or B, except that an initiator containing one active hydrogen atom is used. Two or more initiators may be used in combination. The initiator's active hydrogen-containing group is preferably a hydroxyl group. The precursor polymer is preferably a polymer having one hydroxyl group as a terminal group. As initiators having one hydroxyl group, monohydric alcohols having a linear or branched hydrocarbon group are preferred. Specifically, examples include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-butyl alcohol, t-butyl alcohol, 2-ethylhexanol, decyl alcohol, lauryl alcohol, tridecanol, cetyl alcohol, stearyl alcohol, oleyl alcohol, and low molecular weight polyoxyalkylene monools. The method for producing polymer C can be a conventionally known method, and the same method as for polymers A and B can be used. In other words, the production methods described above, from method (a) to method (c), can be applied to produce polymer C.

[0055] Polymer C has an average of one terminal group per molecule, and the terminal group preferably has a reactive silicon group, an active hydrogen-containing group, an unsaturated group, or an isocyanate group, and more preferably has a reactive silicon group, a hydroxyl group bonded to a carbon atom, an unsaturated group, or an isocyanate group.

[0056] The silylation rate of polymer C is preferably more than 50 mol% and 100 mol% or less, more preferably 51 to 97 mol%, and even more preferably 52 to 95 mol%. When the silylation rate of polymer C is above the lower limit of the above range, the tensile strength of the cured product is superior and the modulus is higher. If the curable composition contains two or more types of polymer C, it is sufficient that the average silylation rate of the entire polymer C is within the above range.

[0057] <Polymer D> The curable composition of this embodiment may contain a vinyl polymer (hereinafter referred to as "polymer D") having an average of one or more reactive silicon groups represented by formula (1) per molecule. The curable composition of this embodiment may contain two or more types of polymer D. Polymer D contributes to weather resistance, water resistance, and the like. The reactive silicon group in polymer D may be introduced at the end of the main chain, at the side chain, or at both the end of the main chain and the side chain. The average number of reactive silicon groups per molecule of polymer D is preferably 0.8 or more. From the viewpoint of tensile strength after curing, it is preferably 1.0 or more, and more preferably 1.2 or more. From the viewpoint of good elongation of the cured product, it is preferably 4.0 or less, and more preferably 3.0 or less. The average number of reactive silicon groups per molecule of polymer D is calculated as "concentration of reactive silicon groups in polymer D [moles / g] × number-average molecular weight of polymer D". The concentration of reactive silicon groups in polymer D [moles / g] can be measured by NMR. For example, the monomers constituting the main chain of polymer D can be conventionally known monomers as described in Japanese Patent Publication No. 3-14068, Japanese Patent Application Publication No. 6-211922, and Japanese Patent Application Publication No. 11-130931. Examples of monomers containing reactive silicon groups and unsaturated groups to be copolymerized with the above monomers include vinyldimethoxymethylsilane, vinyldiethoxymethylsilane, vinylmethyldichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, tris(2-methoxyethoxy)vinylsilane, (meth)acrylate-3-(dimethoxymethylsilyl)propyl, (meth)acrylate-3-(trimethoxysilyl)propyl, and (meth)acrylate-3-(triethoxysilyl)propyl. Two or more of these may be used. The content of (meth)acrylic acid ester monomers relative to the total monomers constituting polymer D is preferably 50% by mass or more, more preferably 70% by mass or more, and may even be 100% by mass.

[0058] Polymer D can be polymerized using conventionally known polymerization methods described in Japanese Patent Publication No. 2006-257405, Japanese Patent Publication No. 2006-37076, Japanese Patent Publication No. 2008-45059, etc. Conventionally known auxiliary materials such as initiators necessary for polymerization can also be used, and reaction conditions such as reaction temperature and reaction pressure can be appropriately selected. Polymerization methods include solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, and polymerization methods using radical polymerization initiators, as well as living radical polymerization. Examples of living radical polymerization methods include those using cobalt porphyrin complexes as shown in the Journal of American Chemical Society (J.Am.Chem.Soc.), 1994, Vol. 116, p. 7943; those using nitrooxide radicals as shown in Japanese Patent Publication No. 2003-500378; and atom transfer radical polymerization (ATRP method) using organic halides or sulfonyl halogen compounds as initiators and transition metal complexes as catalysts, as shown in Japanese Patent Publication No. 11-130931. Polymers obtained by living radical polymerization tend to have a narrow molecular weight distribution and low viscosity. Commercially available polymer D can also be used. Examples of commercially available polymers include the XMAP series (Kaneka Corporation product name), the ARUFON US-6000 series (e.g., US-6110, US-6120, US-6170, etc., all Toagosei Co., Ltd. product names), and the Actflow NE series (e.g., NE-1000, NE-3000, all Soken Chemical Co., Ltd. product names).

[0059] The manganese content of polymer D is preferably 500 to 100,000, more preferably 800 to 80,000, and even more preferably 1,000 to 60,000. If it is above the lower limit of the above range, the cured product tends to have excellent elongation properties and weather resistance, and if it is below the upper limit, it has better workability. The molecular weight distribution of polymer D is preferably 4.0 or less, and more preferably 3.0 or less. When it is below the above upper limit, workability is superior.

[0060] <Polymer E> The curable composition of this embodiment may contain a polymer (hereinafter referred to as "polymer E") that does not have reactive silicon groups and has a number average molecular weight of 1,000 or more. The curable composition of this embodiment may contain two or more types of polymer E. Polymer E contributes to reducing surface contamination of cured products, improving the drying properties of paints on the surface of cured products, reducing surface contamination of paints, and improving the weather resistance of resins. Polymer E is preferably one or more selected from the group consisting of saturated hydrocarbon polymers, (meth)acrylic acid ester polymers, and oxyalkylene polymers.

[0061] Saturated hydrocarbon polymers are polymers whose main chains consist of units based on monomers of saturated hydrocarbons, with polyethylene and polypropylene being examples. Examples of (meth)acrylic acid ester polymers include monomer polymers or copolymers containing methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. Examples of commercially available (meth)acrylic acid ester polymers include ARUFON UP-1000, ARUFON UP-1110, and ARUFON UP-1171 (all product names of Toagosei Co., Ltd.). Examples of oxyalkylene polymers include polyether polyols (e.g., polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol) and derivatives of the above polyether polyols obtained by encapsulating the hydroxyl groups to form esters or ethers. Examples of commercially available oxyalkylene polymers include Exenol 3020 (EL-3020), Preminol S3011, Preminol S4012, and Preminol S4013F (all AGC product names).

[0062] When polymer E is an oxyalkylene polymer, the molecular weight in terms of hydroxyl groups is preferably 1,000 to 40,000, more preferably 1,000 to 35,000, and even more preferably 1,500 to 30,000. If it is above the lower limit of the above range, it is less likely to bleed out from the cured product, and if it is below the upper limit, the viscosity of the curable composition can be lowered, resulting in better workability. The Mn of polymer E is preferably 1,000 to 40,000, more preferably 1,000 to 35,000, and even more preferably 1,500 to 30,000. If it is above the lower limit of the above range, it is less likely to bleed out from the cured product, and if it is below the upper limit, the viscosity of the curable composition can be lowered, resulting in better workability. The molecular weight distribution of polymer E is preferably less than 6.0, more preferably 5.5 or less, and even more preferably 5.0 or less, in the case of (meth)acrylic acid ester polymers. In the case of oxyalkylene polymers, it is preferably less than 2.0, more preferably 1.8 or less, and even more preferably 1.6 or less. Workability is better when the value is below the upper limit.

[0063] <Curable composition> The curable composition is obtained by mixing polymer A with other necessary components. The content of polymer A relative to the total mass of the curable composition is preferably 1 to 50% by mass, more preferably 1 to 45% by mass, and even more preferably 2 to 40% by mass. If the content is below the upper limit of the above range, the tensile strength of the cured product will be superior and the elongation properties will be better. When the curable composition contains polymer B, the content of polymer B relative to the total mass of the curable composition is preferably 1 to 50% by mass, more preferably 1 to 45% by mass, and even more preferably 2 to 40% by mass. If it is above the lower limit of the above range, the elongation properties will be better. If it is below the upper limit of the above range, the tensile strength of the cured product will be better and the modulus will be higher. When the curable composition contains polymer B, the total content ratio of polymer A and polymer B relative to the total mass of the curable composition is preferably 2 to 70% by mass, more preferably 3 to 60% by mass, and even more preferably 4 to 50% by mass. If the ratio is above the lower limit of the above range, the curability is good, the cured product has excellent tensile strength, and the modulus is high. When the curable composition contains polymer B, the ratio of the mass of polymer A to the mass of polymer B is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 to 90 / 10, and even more preferably 20 / 80 to 80 / 20. If the ratio is above the lower limit of the above range, the cured product will have better tensile strength and a higher modulus. If the ratio is below the upper limit of the above range, the elongation properties will be better. When the curable composition contains polymer C, the content ratio of polymer C to 100 parts by mass of polymer A is preferably 1 to 600 parts by mass, more preferably 5 to 500 parts by mass, and even more preferably 10 to 300 parts by mass. If the content is below the upper limit of the above range, bleed-out is easily suppressed in the cured product made from the curable composition. When the curable composition contains polymer D, the content of polymer D relative to 100 parts by mass of polymer A is preferably 1 to 600 parts by mass, more preferably 5 to 500 parts by mass, and even more preferably 10 to 300 parts by mass. If the content is below the upper limit of the above range, the weather resistance of the cured product from the curable composition will be better. When the curable composition contains polymer E, the content of polymer E relative to 100 parts by mass of polymer A is preferably 1 to 600 parts by mass, more preferably 5 to 500 parts by mass, and even more preferably 10 to 300 parts by mass. If the content is below the upper limit of the above range, contamination of the cured product surface by the curable composition is more easily reduced, the drying properties of the paint on the cured product surface are more easily improved, contamination of the paint surface is more easily reduced, and the weather resistance of the cured product is better.

[0064] [Other ingredients] Examples of the other components mentioned above include curable compounds other than polymers A to E such as epoxy resins, epoxy resin curing agents, curing catalysts (silanol condensation catalysts), fillers, plasticizers, thixotropic agents, stabilizers, adhesion modifiers, property modifiers, dehydrating agents, adhesion-improving resins, reinforcing materials such as fillers, surface modifiers, flame retardants, foaming agents, solvents, and silicates. Other components can be used in any combination without limitation from those conventionally known as described in International Publication No. 2013 / 180203, International Publication No. 2014 / 192842, International Publication No. 2016 / 002907, Japanese Patent Publication No. 2014-88481, Japanese Patent Publication No. 2015-10162, Japanese Patent Publication No. 2015-105293, Japanese Patent Publication No. 2017-039728, Japanese Patent Publication No. 2017-214541, etc. Two or more of each component may be used in combination.

[0065] The curable composition may be a one-component type in which the polymer and all other components are pre-mixed and sealed for storage, and cured by moisture in the air after application. Alternatively, it may be a two-component type in which a main component composition containing at least a polymer having reactive silicon groups and a curing agent composition containing at least a curing catalyst are stored separately, and the curing agent composition and the main component composition are mixed before use. It is preferable that the one-component curable composition does not contain water. It is preferable to dehydrate and dry any water-containing components beforehand, or to dehydrate them by reducing the pressure during mixing. In a two-component curable composition, the curing agent composition may contain water, and the main component composition is less likely to gel even if it contains a small amount of water. However, from the viewpoint of storage stability, it is preferable to dehydrate and dry the components beforehand. To improve storage stability, a dehydrating agent may be added to the one-component curable composition or the two-component main component composition.

[0066] [Mechanism of Action] The curable composition of this embodiment has polymer A, which contains an average of 4 to 8 terminal groups per molecule, and the hydroxyl group-equivalent molecular weight of the polymer per terminal group is 500 to 1,750, resulting in a high crosslinking density. Therefore, a cured product with good tensile strength can be obtained. For this reason, it is particularly useful as a material for adhesives that require high tensile strength.

[0067] [Application] Suitable applications for the curable composition of this embodiment include adhesives, sealing materials (e.g., elastic sealing materials for buildings, sealing materials for double-glazed windows, sealing materials for rust prevention and waterproofing of glass edges, back sealing materials for solar cells, sealing materials for buildings, sealing materials for ships, sealing materials for automobiles, sealing materials for roads), and electrical insulating materials (insulating coatings for electric wires and cables). In particular, it is suitable for applications where good tensile strength and elongation properties are required in the cured product, such as adhesives for floors. [Examples]

[0068] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0069] [Hydroxygroup-based molecular weight of precursor polymers] The hydroxyl group-equivalent molecular weight of a precursor polymer, obtained by polymerizing an initiator containing a hydroxyl group with an alkylene oxide, whose terminal groups are hydroxyl groups, was calculated based on the hydroxyl value calculated according to JIS K 1557 (2007) using the formula: "56,100 / (hydroxyl value of the precursor polymer) × number of active hydrogens in the initiator".

[0070] [Number-average molecular weight (Mn) and molecular weight distribution (Mw / Mn)] The measurement device used was the HLC-8220GPC (Tosoh Corporation product name). The column used was TSKgel SupermultiporeHZ-M (Tosoh Corporation product name), and the solvent was tetrahydrofuran. The sample pump was set to a flow rate of 0.350 mL / min, the reference pump was set to a flow rate of 0.350 mL / min, the detector temperature was set to 40°C, and the collection time was set to 6 to 15 minutes. Mw, Mn, and Mw / Mn were determined by analyzing the peaks that appeared between 6 and 11 minutes of collection.

[0071] [Silylation rate, number of silyl groups] When a reactive silicon group was introduced to the terminal group by the method (a) described above, the silylation rate was defined as the molar ratio of the silylating agent to the amount of unsaturated group introduced to the terminal group. When allyl chloride is used as a reagent to convert the hydroxyl groups of the precursor polymer to alkenyloxy groups, approximately 10 mol% of the unsaturated groups do not react with the silylating agent due to side reactions in the reaction between the introduced unsaturated groups and the silylating agent. Therefore, when reacting with less than 90 mol% of the silylating agent relative to the number of moles of unsaturated groups, the aforementioned charge equivalent becomes the silylation rate. On the other hand, when reacting with 90 mol% or more of the silylating agent relative to the number of moles of unsaturated groups, the silylation rate becomes 90%. When a reactive silicon group is introduced to the terminal group by the method (b) described above, the silylation rate is defined as the molar ratio of the silylation agent having a functional group that can react with the hydroxyl group and a reactive silicon group represented by formula (1) to the amount of hydroxyl group, which is the terminal group of the precursor polymer.

[0072] [Tensile test] The curable composition to be measured was filled into a 2 mm thick mold and cured at 23°C and 50% humidity for 3 days, followed by curing at 50°C and 65% humidity for 4 days. These preparation conditions are referred to as "initial curing." The resulting cured material was punched out using a dumbbell mold to obtain test specimens. These specimens were subjected to a tensile test on a Tensilon testing machine at a tensile speed of 500 mm / min, and the modulus (M50, unit: N / mm²) of the stress at 50% elongation was measured. 2 ), tensile strength (Tmax, unit: N / mm²), which is the maximum point cohesive force. 2 ), and the maximum point elongation (elongation characteristic, unit: %) were measured. Furthermore, after curing the prepared cured material under the "initial curing" conditions described above, it was cured at 90°C for 7 days. These conditions are referred to as "heat-resistant curing." The resulting cured material was punched out using a dumbbell mold to obtain test specimens. These test specimens were subjected to tensile testing at a tensile speed of 500 mm / min using a Tensilon testing machine, and the modulus (M50, unit: N / mm) was determined. 2 ), tensile strength (Tmax, unit: N / mm 2 ), and the maximum point elongation (elongation characteristic, unit: %) were measured. The modulus (M50) has a curing strength of 0.85 N / mm² for "initial curing" and "heat-resistant curing". 2 If the above is true, it will be judged as good. The tensile strength (Tmax) is 1.30 N / mm² for "initial curing" and "heat-resistant curing".2 If the above conditions are met, the result will be considered good.

[0073] [Viscosity measurement] A 1 mL sample of the modified silicone polymer, obtained by mixing polymer A and polymer B, was taken, and its viscosity was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: RE80) at a measurement temperature of 25°C and rotor No. 4. JS14000 (manufactured by Nippon Grease Co., Ltd., product name) was used as the calibration standard solution.

[0074] [Synthesis of Polymer A, Polymer a, and Polymer B] (Synthesis example 1: Polymer (A-1)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 550 and containing four hydroxyl groups as an initiator, and a zinc hexacyanocobaltate complex with t-butyl alcohol as a ligand (hereinafter referred to as "TBA-DMC catalyst") as a catalyst, propylene oxide was polymerized to obtain an oxypropylene polymer (precursor polymer P1). Precursor polymer P1 had four hydroxyl groups per molecule and a hydroxyl group-equivalent molecular weight of 5,000. A methanol solution of sodium methoxide (concentration 28% by mass, the same applies hereafter) in an amount of 1.15 molar equivalents was added to the hydroxyl groups of the precursor polymer P1. After removing the methanol by vacuum degassing, an excess amount of allyl chloride was added relative to the amount of hydroxyl groups of the precursor polymer P1, and the mixture was reacted at 130°C for 2 hours to convert the hydroxyl groups to allyloxy groups. Next, in the presence of a platinum divinyldisiloxane complex, 0.73 molar equivalents of dimethoxymethylsilane was added as a silylating agent relative to the allyloxy groups. After reacting at 70°C for 5 hours, the unreacted silylating agent was removed under reduced pressure to obtain an oxypropylene polymer (polymer (A-1)) in which dimethoxymethylsilyl groups were introduced as reactive silicon groups at the terminal groups. Table 1 shows the number of terminal groups, hydroxyl group-equivalent molecular weight, hydroxyl group-equivalent molecular weight per terminal group (shown in the "Molecular Weight per Terminal Group" column in the table), ethylene oxide unit content in the precursor polymer (shown in the "EO Content of Precursor Polymer" column in the table), silylation rate, average number of reactive silicon groups per molecule, Mn, and Mw / Mn of polymer (the same applies hereafter).

[0075] (Synthesis example 2: Polymer (A-2)) Using a polyoxypropylene polyol with a hydroxyl group-based molecular weight of approximately 870 and containing six hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P2). Precursor polymer P2 had six hydroxyl groups per molecule and a hydroxyl group-based molecular weight of 5,000. Except for using precursor polymer P2 instead of precursor polymer P1, and adding dimethoxymethylsilane in an amount of 0.65 molar equivalents relative to the allyloxy group, the same procedure as in Synthesis Example 1 was used to obtain an oxypropylene polymer (polymer (A-2)) in which dimethoxymethylsilyl groups were introduced as terminal groups.

[0076] (Synthesis example 3: Polymer (A-3)) Using a polyoxypropylene polyol with a hydroxyl group-based molecular weight of approximately 870 and containing six hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P3). Precursor polymer P3 contained six hydroxyl groups per molecule and had a hydroxyl group-based molecular weight of 7,500. Except for using precursor polymer P3 instead of precursor polymer P1, and adding dimethoxymethylsilane in an amount of 0.69 molar equivalents relative to the allyloxy group, the same procedure as in Synthesis Example 1 was used to obtain an oxypropylene polymer (polymer (A-3)) in which dimethoxymethylsilyl groups were introduced as terminal groups.

[0077] (Synthesis example 4: Polymer (A-4)) The reactor containing the precursor polymer P1 was purged with nitrogen gas, and while maintaining the internal temperature at 50°C, 3-isocyanatetopropylmethyldimethoxysilane was added so that the NCO / precursor polymer P1 OH (molar ratio) was 0.97. Dioctyltinbisisooctylthioglycol (Neostan U-860: Nitto Chemical Co., Ltd. product name) was added as a catalyst. The temperature was raised to 80°C and stirred while maintaining the temperature at 80°C. Analysis using a Fourier transform infrared spectrophotometer confirmed the completion of the reaction between the hydroxyl group and the isocyanate group, and the reaction was continued to obtain an oxypropylene polymer (polymer (A-4)) with dimethoxymethylsilyl groups introduced as terminal groups. 0.06 parts by mass of 3-mercaptopropyltrimethoxysilane (KBM-803: Shin-Etsu Chemical Co., Ltd. product name) was added as a storage stabilizer to 100 parts by mass of polymer (A-4).

[0078] (Synthesis example 5: Polymer (A-5)) In Synthesis Example 4, the precursor polymer was changed from P1 to P3. Otherwise, the process was the same as in Synthesis Example 4 to obtain an oxypropylene polymer (polymer (A-5)) in which a dimethoxymethylsilyl group was introduced as a terminal group. 0.06 parts by mass of KBM-803 was added to 100 parts by mass of polymer (A-5).

[0079] (Synthesis example 6: Polymer (A-6)) In Synthesis Example 4, 3-isocyanatetopropylmethyldimethoxysilane was replaced with 3-isocyanatetopropyltrimethoxysilane. Otherwise, the process was the same as in Synthesis Example 4 to obtain an oxypropylene polymer (polymer (A-6)) with a trimethoxysilyl group introduced as a terminal group. 0.06 parts by mass of KBM-803 was added to 100 parts by mass of polymer (A-6).

[0080] (Synthesis Example 7: Polymer (A-7)) In Synthesis Example 4, the precursor polymer was changed from P1 to P3, and 3-isocyanatetopropylmethyldimethoxysilane was changed to 3-isocyanatetopropyltrimethoxysilane. Otherwise, the process was the same as in Synthesis Example 4 to obtain an oxypropylene polymer (polymer (A-7)) in which a trimethoxysilyl group was introduced as a terminal group. 0.06 parts by mass of KBM-803 was added to 100 parts by mass of polymer (A-7).

[0081] (Synthesis example 8: Polymer (A-8)) Using a polyoxypropylene polyol with a hydroxyl group-based molecular weight of approximately 870 and containing six hydroxyl groups as an initiator, propylene oxide was polymerized in the presence of potassium hydroxide to obtain an oxypropylene polymer (precursor polymer P8). Precursor polymer P8 contained six hydroxyl groups per molecule and had a hydroxyl group-based molecular weight of 7,500. An oxypropylene polymer (polymer (A-8)) with a trimethoxysilyl group introduced as a terminal group was obtained in the same manner as in Synthesis Example 7, except that precursor polymer P8 was used instead of precursor polymer P3. 0.06 parts by mass of KBM-803 was added to 100 parts by mass of polymer (A-8).

[0082] (Synthesis example 9: Polymer (A-9)) A polyoxypropylene polyol having 6 hydroxyl groups and a hydroxyl group-equivalent molecular weight of approximately 1000 was used as an initiator. Propylene oxide was polymerized in the presence of potassium hydroxide, followed by polymerization of ethylene oxide to obtain an oxypropyleneoxyethylene polymer (precursor polymer P9). Polymerization was carried out so that the content of repeating units based on ethylene oxide monomers relative to the total mass of the polymer was 13% by mass. Precursor polymer P9 had 6 hydroxyl groups per molecule and a hydroxyl group-equivalent molecular weight of 9,600. An oxypropylene oxyethylene polymer (polymer (A-9)) with a trimethoxysilyl group introduced as a terminal group was obtained in the same manner as in Synthesis Example 7, except that the precursor polymer was changed from P3 to P9. 0.06 parts by mass of KBM-803 were added to 100 parts by mass of polymer (A-9).

[0083] (Synthesis Example 10: Polymer (A-10)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 1200 and containing four hydroxyl groups as an initiator, propylene oxide was polymerized in the presence of potassium hydroxide to obtain an oxypropyleneoxyethylene polymer (precursor polymer P10). The polymerization was carried out so that the content of repeating units based on ethylene oxide monomers relative to the total mass of the polymer was 15% by mass. Precursor polymer P10 had four hydroxyl groups per molecule and a hydroxyl group-equivalent molecular weight of 6,700. An oxypropylene oxyethylene polymer (polymer (A-10)) with a trimethoxysilyl group introduced as a terminal group was obtained in the same manner as in Synthesis Example 7, except that the precursor polymer P3 was changed to P10. 0.06 parts by mass of KBM-803 was added to 100 parts by mass of polymer (A-10).

[0084] (Synthesis Example 11: Polymer (a-1)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 550 and containing four hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P11). Precursor polymer P11 had four hydroxyl groups per molecule and a hydroxyl group-equivalent molecular weight of 8,000. Except for using precursor polymer P11 instead of precursor polymer P1 and adding dimethoxymethylsilane in an amount of 0.73 molar equivalents relative to the allyloxy group, an oxypropylene polymer (comparative polymer (a-1)) with dimethoxymethylsilyl groups introduced as terminal groups was obtained in the same manner as in Synthesis Example 1.

[0085] (Synthesis Example 12: Polymer (B-1)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 1,000 and containing three hydroxyl groups as an initiator, and a TBA-DMC catalyst, propylene oxide was polymerized to obtain an oxypropylene polymer (precursor polymer P12). Precursor polymer P12 contained three hydroxyl groups per molecule and had a hydroxyl group-equivalent molecular weight of 10,000. A methanol solution of sodium methoxide (concentration 28% by mass, the same applies hereafter) in an amount of 1.15 molar equivalents was added to the hydroxyl groups of the precursor polymer P12. After removing the methanol by vacuum degassing, an excess amount of allyl chloride was added relative to the amount of hydroxyl groups of the precursor polymer P12, and the mixture was reacted at 130°C for 2 hours to convert the hydroxyl groups to allyloxy groups. Next, in the presence of a platinum divinyldisiloxane complex, 0.66 molar equivalents of dimethoxymethylsilane was added as a silylation agent relative to the allyloxy groups. After reacting at 70°C for 5 hours, the unreacted silylation agent was removed under reduced pressure to obtain an oxypropylene polymer (polymer (B-1)) in which dimethoxymethylsilyl groups were introduced as reactive silicon groups at the terminal groups. The items for polymer (B-1) that correspond to the items listed in Table 1 for polymer (A-1) are shown in Table 1. (The same applies hereafter).

[0086] (Synthesis Example 13: Polymer (B-2)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 1,000 and containing three hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P13). Precursor polymer P13 contained three hydroxyl groups per molecule and had a hydroxyl group-equivalent molecular weight of 24,000. Except for using precursor polymer P13 instead of precursor polymer P12 and adding dimethoxymethylsilane in an amount of 0.85 molar equivalents relative to the allyloxy group, an oxypropylene polymer (polymer (B-2)) with dimethoxymethylsilyl groups introduced as terminal groups was obtained in the same manner as in Synthesis Example 12.

[0087] (Synthesis Example 14: Polymer (B-3)) Using a polyoxypropylene polyol with a hydroxyl group-based molecular weight of approximately 2,000 and containing two hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P14). Precursor polymer P14 contained two hydroxyl groups per molecule and had a hydroxyl group-based molecular weight of 12,000. Except for using precursor polymer P14 instead of precursor polymer P12 and adding dimethoxymethylsilane in an amount of 0.85 molar equivalents relative to the allyloxy group, an oxypropylene polymer (polymer (B-3)) with dimethoxymethylsilyl groups introduced as terminal groups was obtained in the same manner as in Synthesis Example 12.

[0088] (Synthesis Example 15: Polymer (B-4)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 1,000 and containing three hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P15). Precursor polymer P15 contained three hydroxyl groups per molecule and had a hydroxyl group-equivalent molecular weight of 3,000. Except for using precursor polymer P15 instead of precursor polymer P12 and adding dimethoxymethylsilane in an amount of 0.72 molar equivalents relative to the allyloxy group, an oxypropylene polymer (polymer (B-4)) with dimethoxymethylsilyl groups introduced as terminal groups was obtained in the same manner as in Synthesis Example 12.

[0089] (Synthesis Example 16: Polymer (B-5)) Using a polyoxypropylene polyol with a hydroxyl group-equivalent molecular weight of approximately 1,000 and containing three hydroxyl groups as an initiator, propylene oxide was polymerized using a TBA-DMC catalyst to obtain an oxypropylene polymer (precursor polymer P16). Precursor polymer P16 contained three hydroxyl groups per molecule and had a hydroxyl group-equivalent molecular weight of 5,000. Except for using precursor polymer P16 instead of precursor polymer P12 and adding dimethoxymethylsilane in an amount of 0.72 molar equivalents relative to the allyloxy group, an oxypropylene polymer (polymer (B-5)) with dimethoxymethylsilyl groups introduced as terminal groups was obtained in the same manner as in Synthesis Example 12.

[0090] (Synthesis Example 17: Polymer (B-6)) In Synthesis Example 7, the precursor polymer was changed from P3 to P15. Otherwise, the process was the same as in Synthesis Example 7 to obtain an oxypropylene polymer (polymer (B-6)) with a trimethoxysilyl group introduced as a terminal group. 0.06 parts by mass of KBM-803 was added to 100 parts by mass of polymer (B-6).

[0091] (Synthesis Example 18: Polymer (C-1)) Using n-butyl alcohol as an initiator, propylene oxide was polymerized in the presence of a TBA-DMC catalyst to obtain a precursor polymer c1 with a hydroxyl group-based molecular weight of 5,000. To the allyloxy group of precursor polymer c1, where the hydroxyl end group was converted to an allyloxy group, 0.80 molar equivalents of dimethoxymethylsilane were added as a silylating agent. The reaction was carried out at 70°C for 5 hours to obtain an oxypropylene polymer (polymer (C-1)) in which dimethoxymethylsilyl groups were introduced as reactive silicon groups at the end. The number-average molecular weight (Mn) of polymer (C-1) was 8,000, and the Mw / Mn ratio was 1.10.

[0092] (Synthesis Example 19: Polymer (D-1)) 50 g of isobutanol was added to a pressure reactor equipped with a stirrer, and the temperature was raised to approximately 80°C. Maintaining the temperature inside the reaction vessel at approximately 80°C, and under a nitrogen atmosphere with stirring, a mixed solution of 1.65 g of methyl methacrylate, 373.1 g of n-butyl acrylate, 110.0 g of stearyl acrylate, 6.5 g of 3-methacryloxypropylmethyldimethoxysilane (KBM-502, Shin-Etsu Silicone Co., Ltd. product name), and 7.3 g of 2,2'-azobis-2,4-dimethylvaleronitrile (V-65, Wako Pure Chemical Industries, Ltd. product name) was added dropwise to the isobutanol over 2 hours to polymerize and obtain a (meth)acrylic acid ester polymer (polymer (D-1)) having dimethoxymethylsilyl groups in the side chains. The average number of reactive silicon groups per molecule is 1 ¹H-NMR analysis revealed 2.0 molecules. The number-average molecular weight (Mn) of polymer (D-1) was 35,000, and the Mw / Mn ratio was 2.2.

[0093] (Synthesis example 20: Polymer (D-2)) Polymer D-2 was synthesized using the living radical polymerization method, in which a compound having two alkenyl groups was reacted at the end of the polymerization reaction. 8.39 g of cuprous bromide and 112 mL of acetonitrile were added to a 2 L flask and heated and stirred at 70°C under a nitrogen stream for 20 minutes. 17.6 g of diethyl 2,5-dibromoadipate, 130 mL of ethyl acrylate, 720 mL of butyl acrylate, and 251 g of stearyl acrylate were added and heated and stirred at 70°C for a further 40 minutes. 0.41 mL of pentamethyldiethylenetriamine (hereinafter referred to as "triamine") was added to initiate the reaction. Heating and stirring continued at 70°C, and 2.05 mL of triamine was added. 330 minutes after the start of the reaction, 244 mL of 1,7-octadiene and 4.1 mL of triamine were added and heating and stirring continued at 70°C. Heating was stopped 570 minutes after the start of the reaction. The resulting reaction solution was diluted with toluene and filtered. The filtrate was subjected to reduced-pressure heating to obtain an acrylic ester polymer having alkenyl groups at its terminals (polymer (d1)). Polymer (d1) had a manganese content of 22,800 and a molecular weight distribution of 1.40. 1 The average number of alkenyl groups per molecule of polymer (d1), as determined by 1H-NMR analysis, was 2.8. Under a nitrogen atmosphere, the entire amount of the obtained polymer (d1), 17.2 g of potassium acetate, and 700 mL of N,N-dimethylacetamidomethyl (hereinafter referred to as "DMAc") were added to a 2 L flask and heated and stirred at 100°C for 10 hours. The reaction solution was heated under reduced pressure to remove the DMAc, and toluene was added and the mixture was filtered. The filtrate was heated under reduced pressure to remove volatile components, and the remainder was added to a 2 L flask. 100 g of adsorbent (a mixture of Kyowa Chemical 500SN and Kyowa Chemical 700SN in a 1:1 mass ratio) was added and the mixture was heated and stirred at 130°C under a nitrogen stream for 9 hours. The mixture was diluted with toluene, filtered to remove the adsorbent, and the toluene in the filtrate was removed under reduced pressure to obtain the polymer (polymer (d2)). 700 g of polymer (d2), 22.2 mL of dimethoxymethylhydrosilane, 7.71 mL of methyl orthoformate, and a platinum catalyst (1,1,3,3-tetramethyl-1,3-divinyldisiloxane complex of zero-valent platinum) were added to a 1 L pressure-resistant reaction vessel. However, the amount of platinum catalyst used was 9 × 10⁶ relative to the alkenyl groups of polymer (d2). -3 The amount was measured in molar equivalents. The mixture in the reaction vessel was heated and stirred at 100°C for 195 minutes. The volatile components of the mixture were removed by distillation under reduced pressure to obtain a polymer having dimethoxymethylsilyl groups at the terminal groups (polymer (D-2)). The average number of reactive silicon groups per molecule is 1 ¹H-NMR analysis revealed 2.0 molecules. The number-average molecular weight (Mn) of polymer (D-2) was 28,000, and the Mw / Mn ratio was 1.7.

[0094] [Other ingredients] The additives listed in Tables 2, 6, and 7 are as follows: Whiten SB: Heavy calcium carbonate, product name of Shiraishi Calcium Co., Ltd. White Glossy CCR (CCR): Collagenous calcium carbonate, product name of Shiraishi Calcium Co., Ltd. Vinisizer 90 (DINP): Diisononyl phthalate, Kao Corporation product name DINCH: 1,2-Cyclohexanedicarboxylic acid diisononyl ester, BASF product name EL-3020: A polyether polyol with a molecular weight of 1,500 per hydroxyl group and containing two hydroxyl groups per molecule; AGC Corporation product name. UP-1110: Acrylic polymer, product name of Toagosei Co., Ltd. Epicote 828: Epoxy resin, product name of Mitsubishi Chemical Corporation. Epicure H3: Epoxy resin hardener, product name of Mitsubishi Chemical Corporation. DMP-30: Epoxy resin curing agent, 2,4,6-tris(dimethylaminomethyl)phenol, Fujifilm & Wako Pure Chemical Industries, Ltd. Disparon #6500: Hydrogenated castor oil-based thixotropic agent, product name of Kusumoto Chemical Co., Ltd. IRGANOX 1010: Hindered phenol antioxidant, BASF product name TINUVIN 326: Benzotriazole-based light stabilizer, BASF product name KBM-1003: Vinyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd. product name KBM-403:3-Glycidyloxypropyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd. product name KBM-603: 3-(2-aminoethylamino)propyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd. product name DBTDL: Dibutyltin dilaurate U-220H: Dibutyltin bis(acetylacetonate), Nitto Kasei Co., Ltd. product name U-810: Dioctyl tin catalyst, Nitto Chemical Co., Ltd. product name TC-750: Titanium diisopropoxybis(ethyl acetoacetate), product name of Matsumoto Fine Chemical Co., Ltd.

[0095] [Preparation of curable compositions] Examples 1-9, 13, 14, 17, 18 and 20-42 are examples, while Examples 10-12, 15, 16 and 19 are comparative examples.

[0096] (Examples 1-26) Curable compositions were prepared using polymers having reactive silicon groups in the amounts (parts by mass) shown in Tables 3-4 and additives in the amounts (parts by mass) shown in Table 2. The amounts of each component shown in Table 2 are values ​​relative to 100 parts by mass of polymer A or comparative polymer a and polymer B (Tables 3 and 4), or values ​​relative to 100 parts by mass of polymer A, polymer B, polymer C, and polymer D (Table 5) (unit: parts by mass). Note that the additive amounts for polymers (A-4) to (A-10) and (B-6) in Tables 3-5 represent the additive amounts for compositions in which 0.06 parts by mass of KBM-803 is added to 100 parts by mass of each polymer (A-4) to (A-10) and (B-6). Tensile properties tests were conducted using the obtained curable compositions. The results are shown in Tables 3-5.

[0097] (Examples 27-42) In Examples 1-4 of Table 3, the additives were changed to additives 5-8 of Table 2 to prepare curable compositions, which were then evaluated in the same manner as described above. Examples 27-30 are examples in which additive 5 was added, Examples 31-34 are examples in which additive 6 was added, Examples 35-38 are examples in which additive 7 was added, and Examples 39-42 are examples in which additive 8 was added. In all of the cured products obtained, the modulus (M50) and tensile strength (Tmax) were good in the tensile tests described above.

[0098] [Table 1]

[0099] [Table 2]

[0100] [Table 3]

[0101] [Table 4]

[0102] As shown in Table 3 or Table 4, high modulus and excellent tensile strength (Tmax) were obtained in Examples 1-9, 13, 14, 20, and 21. As shown in Table 4, the elongation of Examples 17-19 did not reach 50%, so M50 could not be measured, but excellent tensile strength (Tmax) was obtained in Examples 17 and 18. As shown in Table 3 or Table 4, the tensile strength (Tmax) was inferior in Examples 10, 11, 15, 16, and 19, which did not contain polymer A and contained polymers (B-1), (B-3), (B-4), and (B-5) having three or fewer terminal groups per molecule. The tensile strength (Tmax) was inferior in Example 12, which did not contain polymer A and contained polymer (a-1) having four terminal groups per molecule with a hydroxyl group-equivalent molecular weight of the oxyalkylene polymer A per terminal group of 2,000.

[0103] [Table 5]

[0104] As shown in Table 5, Example 26, which further included polymer (C-1), obtained high modulus and excellent tensile strength (Tmax). In Examples 22 and 23, although the elongation did not reach 50% and therefore M50 could not be measured, excellent tensile properties (Tmax) were obtained by using epoxy resin or epoxy resin and polymer (D-1) in combination in the formulation (additive 9). Furthermore, as shown in Examples 24 and 25, high modulus and excellent tensile properties (Tmax) were obtained even with formulations using polymer (D-1) or polymer (D-2).

[0105] (Reference examples 1 and 2) As reference examples 1 and 2, additives as shown in Table 6 were added to polymer (A-7) and polymer (B-6), and tack-free time measurements and deep curing tests were performed using the following method. The results are shown in Table 6.

[0106] [Measurement of tack-free time] The evaluation was conducted in accordance with the method described in JIS A 1439 (2016), 5.19 "Touch-dry time test". A shorter time indicates a faster curing speed.

[0107] [Deep hardening test] A cylindrical polyethylene tube with an inner diameter of 24 mm and a height of 55 mm was placed in a stable position with one opening in contact with an aluminum plate. In an atmosphere of 23°C and 50% relative humidity, the curable compositions obtained in Reference Examples 1 and 2 were filled into the tube from the other opening, taking care to prevent air bubbles from entering. The curable composition that had overflowed from the other opening of the tube filled with the curable composition was scraped off with a spatula to flatten the surface of the curable composition at the end of the tube, and a test specimen was obtained. The obtained test specimen was left to stand in the aforementioned atmosphere, and after 1 day, 3 days, and 7 days, the extent to which the curing had progressed from the surface toward the interior of the curable composition was examined. Specifically, the hardened surface layer (hardened portion) of the curable composition was removed with a spatula, the unhardened curable composition adhering to the removed hardened portion was removed, and the thickness (unit: mm) (in the height direction of the tube) of the obtained hardened portion was measured using calipers. The removed hardened portion was often cylindrical, so the thickest part of the hardened portion was measured. The greater the thickness of the hardened portion, the better the deep hardening properties.

[0108] [Table 6]

[0109] As shown in Table 6, when comparing polymers (A-7) and (B-6) with nearly equivalent hydroxyl group molecular weights per terminal group and identical terminal group structures, polymer (A-7) with six terminal groups exhibited a shorter tack-free time and faster curing speed in deep curing tests than polymer (B-6) with three terminal groups.

[0110] (Reference example 3) As Reference Example 3, the tensile test described above was performed using curable compositions obtained by adding the additives shown in Table 7 to polymer (A-7) and polymer (B-3). The curable compositions were obtained by a two-component curable composition preparation method. Specifically, the main component A and the curing agent B were prepared separately in advance by adding the polymers and additives having reactive silicon groups in the amounts (parts by mass) shown in Table 7, and then these were mixed to prepare the curable composition. The units of the amounts of each component shown in Table 7 are parts by mass. Note that the amount of polymer (A-7) added in Table 7 represents the amount added to a composition in which 0.06 parts by mass of KBM-803 is added to 100 parts by mass of polymer (A-7).

[0111] [Table 7]

[0112] The curable composition obtained by the above two-component preparation method cured well, and the resulting cured product was confirmed to have good tensile strength (Tmax) in the above tensile test.

Claims

1. A curable composition comprising an oxyalkylene polymer A having an average of 4 to 8 terminal groups per molecule, each having a reactive silicon group represented by the following formula (1), wherein the terminal groups are the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group, and the hydroxyl group-equivalent molecular weight of the oxyalkylene polymer A per terminal group is 500 to 1,750, wherein the main chain of the oxyalkylene polymer A is a polymerization chain consisting of an initiator residue and an oxyalkylene chain containing repeating units based on one or more alkylene oxide monomers, and the oxyalkylene chain is a polymerization chain consisting of repeating units based on a propylene oxide monomer or a polymerization chain consisting of repeating units based on an ethylene oxide monomer and repeating units based on a propylene oxide monomer. -SiX ａ R ３－ａ Equation (1) [In the formula, R represents a monovalent organic group having 1 to 20 carbon atoms, excluding hydrolyzable groups, and X represents a halogen atom, a hydroxyl group, or a hydrolyzable group. a is an integer from 1 to 3. When a is 2 or greater, X may be the same or different from each other, and when a is 1, R may be the same or different from each other.]

2. The curable composition according to claim 1, wherein the number average molecular weight per terminal group of polymer A is 600 to 2,750.

3. The curable composition according to claim 1 or 2, wherein the polymer A has an average of 0.5 to 1.0 reactive silicon groups represented by formula (1) per terminal group.

4. The curable composition according to claim 1 or 2, wherein the silylation rate of polymer A is 50 to 100 mol%.

5. The curable composition according to claim 1 or 2, wherein the content of repeating units based on the ethylene oxide monomer relative to the total mass of polymer A is 0.1 to 30% by mass.

6. The curable composition according to claim 1, further comprising an oxyalkylene polymer B having an average of 2 to 3 terminal groups per molecule and a reactive silicon group represented by formula (1), wherein the terminal groups are the reactive silicon group, an unsaturated group, an isocyanate group, or an active hydrogen-containing group.

7. The curable composition according to claim 6, wherein the polymer B has an average of 0.1 to 1.0 reactive silicon groups represented by formula (1) per terminal group.

8. The curable composition according to claim 6 or 7, wherein the hydroxyl group-equivalent molecular weight of polymer B is 1,000 to 100,000.

9. The curable composition according to claim 6 or 7, wherein the ratio of the mass of polymer A to the mass of polymer B is 5 / 95 to 95 / 5.

10. The curable composition according to claim 1 or 6, further comprising a linear oxyalkylene polymer C having an average of one terminal group per molecule, wherein the terminal group has a reactive silicon group represented by formula (1), and the number average molecular weight is 2,000 or more.

11. The curable composition according to claim 1 or 6, further comprising a vinyl polymer D having an average of one or more reactive silicon groups represented by formula (1) per molecule.

12. A cured product of the curable composition according to claim 1 or 2.

13. An adhesive comprising the cured product described in claim 12.

14. A sealing material comprising the cured product described in claim 12.

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