Method for producing organic polymers

Abstract

An organic polymer according to the present invention includes a reactive silyl group represented by the formula: -S-CH2-SiR1 aX3-a. (In this formula, R1 represents a substituted or unsubstituted hydrocarbon group having 1-20 carbon atoms, X represents a hydroxyl group or a hydrolyzable group, and a is 0, 1, or 2. When there are multiple R1 or X present, these may respectively be the same or may be different.) The introduction ratio of the reactive silyl group is 60% or greater.

Description

[Technical field]

[0001] The present invention relates to an organic polymer having a reactive silyl group, a curable composition, and a cured product. [Background technology]

[0002] Organic polymers having a silicon-containing group (hereinafter referred to as a "reactive silyl group") that has a hydroxyl group or a hydrolyzable group on a silicon atom and can form a siloxane bond are known as moisture-reactive polymers, and are included in many industrial products such as adhesives, sealing materials, coating materials, paints, and pressure sensitive adhesives, and are used in a wide range of fields. As such reactive silyl group-containing polymers, various polymers whose main chain skeletons are polyoxyalkylene-based polymers, saturated hydrocarbon-based polymers, and (meth)acrylic acid ester-based copolymers are known.

[0003] As a method for producing a reactive silyl group-containing polymer, for example, a method is known in which an epoxy compound is subjected to ring-opening polymerization to synthesize a polyoxyalkylene polymer having a hydroxyl group at its terminal, the hydroxyl group is converted to a carbon-carbon double bond, and the carbon-carbon double bond is subjected to a hydrosilylation reaction with a silane compound to introduce a reactive silyl group into the polymer (see, for example, Patent Document 1). However, the curability of the reactive silyl group-containing polymer obtained by this method is not necessarily sufficient, and there is a demand for improving this.

[0004] Patent Document 2 discloses a reactive silyl group-containing polymer with improved curability, in which a reactive silyl group is bonded to the polymer backbone via a sulfide bond. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 52-73998 [Patent Document 2] JP 2017-141450 A Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 2 describes the synthesis of a polymer in which a reactive silyl group is bonded to the polymer backbone via a sulfide bond by reacting an allyl-terminated polymer with mercaptomethyltrimethoxysilane in the presence of a radical initiator (thiol-ene reaction).

[0007] However, according to the studies of the present inventors, it was found that the organic polymer synthesized under the production conditions disclosed in Patent Document 2 does not give a cured product obtained by curing the polymer with a sufficiently high tensile strength, and in this respect there is room for improvement.

[0008] In view of the above-mentioned current situation, an object of the present invention is to provide an organic polymer which has a reactive silyl group bonded to the polymer backbone via a sulfide bond and is capable of forming a cured product exhibiting high tensile strength. [Means for solving the problem]

[0009] As a result of intensive research, the present inventors have found that the introduction rate of reactive silyl groups in the produced organic polymer is not sufficiently high because side reactions occur in both the allyl-terminated polymer and mercaptomethyltrimethoxysilane under the production conditions disclosed in Patent Document 2. Furthermore, the present inventors have found that by adopting specific production conditions when synthesizing the organic polymer and increasing the introduction rate of reactive silyl groups in the polymer, the cured material formed from the organic polymer can exhibit high tensile strength (modulus value), and have arrived at the present invention.

[0010] That is, the present invention relates to a compound represented by the following general formula (1): -S-CH2-SiR 1 a X 3-a (1) (In the formula, R 1represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. X represents a hydroxyl group or a hydrolyzable group. a is 0, 1 or 2. R 1 or when a plurality of X's are present, they may be the same or different; The present invention relates to an organic polymer having a reactive silyl group introduction rate of 60% or more. Preferably, the polymer backbone of the organic polymer is a polyoxyalkylene polymer. The present invention also provides a method for producing the organic polymer, comprising the steps of: An organic polymer having a carbon-carbon double bond and a compound represented by the following general formula (2): HS-CH2-SiR 1 a X 3-a (2) (In the formula, R 1 , X, and a are the same as defined above.) in the presence of a radical initiator, The present invention also relates to a production method in which the reaction is carried out while adding the radical initiator in portions or continuously to a system containing the organic polymer having a carbon-carbon double bond and the mercapto group-containing compound. Preferably, the amount of the mercapto group-containing compound used is 1.2 molar times or more relative to the carbon-carbon double bond. Preferably, the total amount of the radical initiator used is 0.2 parts by weight or more based on 100 parts by weight of the organic polymer having a carbon-carbon double bond. Preferably, the process further comprises the step of distilling off volatile matters under reduced pressure at a temperature of 130° C. or higher after the reaction. The present invention further relates to a curable composition containing the organic polymer, and a cured product obtained by curing the curable composition. Effect of the Invention

[0011] According to the present invention, it is possible to provide an organic polymer which has reactive silyl groups bonded to the polymer backbone via sulfide bonds and which is capable of forming a cured product exhibiting high tensile strength. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail. (Organic polymer) The present invention relates to an organic polymer having a reactive silyl group, which exhibits curability based on hydrolysis and dehydration condensation reactions of the reactive silyl group.

[0013] The organic polymer has a polymer skeleton composed of a plurality of repeating units and a terminal structure bonded to the end of the polymer skeleton. The polymer skeleton refers to a polymer main chain composed of a plurality of repeating units. The polymer skeleton of the organic polymer may be linear or branched. A linear polymer skeleton is preferred in that the cured product of the curable composition has high elongation, and a branched polymer skeleton is preferred in that the cured product of the curable composition has high tensile strength. When the polymer skeleton of the organic polymer is a polyoxyalkylene polymer, the linear polymer skeleton can be formed by using an initiator having one or two hydroxyl groups in one molecule in the polymerization method for forming the polymer skeleton, and the branched polymer skeleton can be formed by using an initiator having three or more hydroxyl groups in one molecule.

[0014] The polymer skeleton is preferably a polymer skeleton consisting of only a plurality of repeating units linked together, or a polymer skeleton consisting of only the plurality of repeating units and including a structure derived from an initiator used during polymerization. When the polymer skeleton of the organic polymer is a polyoxyalkylene polymer, the repeating unit refers to an oxyalkylene unit, for example, an oxyalkylene unit having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms.

[0015] The terminal structure refers to a portion that does not contain a repeating unit constituting the polymer skeleton and is bonded to the end of the polymer skeleton. When the polymer skeleton of the organic polymer is a polyoxyalkylene polymer, the terminal structure is preferably bonded to an oxyalkylene unit located at the end of the polymer skeleton via an oxygen atom. In addition, the reactive silyl group possessed by the organic polymer is preferably contained in the terminal structure. In this case, each terminal structure may contain a reactive silyl group, or a terminal structure containing a reactive silyl group and a terminal structure not containing a reactive silyl group may coexist.

[0016] The organic polymer has reactive silyl groups at a specific ratio. That is, the reactive silyl group introduction rate is 60% or more. An organic polymer that satisfies this condition can form a cured product that exhibits high tensile strength. The reactive silyl group introduction rate can be expressed as 100 x the number of moles of reactive silyl groups contained in the organic polymer / (the number of moles of reactive silyl groups contained in the organic polymer + the number of moles of groups capable of introducing reactive silyl groups contained in the organic polymer that remain without the introduction of reactive silyl groups + the number of moles of groups that are isomerized from the groups capable of introducing reactive silyl groups). Specifically, the value of the reactive silyl group introduction rate is the ratio of the number of moles ... groups capable of introducing reactive silyl groups to the number of moles of the groups that are isomerized from the groups that can be introduced). 1 H NMR measurement can be performed and the determination can be made based on the integral values ​​of the signals indicating each group.

[0017] The reactive silyl group introduction rate is 60% or more, but since the organic polymer can exhibit higher tensile strength after curing, it is preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and particularly preferably 95% or more. The upper limit of the reactive silyl group introduction rate is not particularly limited, and may be 100% or less. In addition, in order for the organic polymer to maintain its curability and for the cured product to exhibit sufficient flexibility, the reactive silyl group introduction rate is preferably 95% or less, more preferably 90% or less, even more preferably 85% or less, and particularly preferably 80% or less. In order to exhibit high tensile strength, maintain its curability, and furthermore for the cured product to exhibit sufficient flexibility, it is particularly preferable for the reactive silyl group introduction rate to be 60% or more and 80% or less.

[0018] The reactive silyl group of the organic polymer is represented by the following general formula (1): -S-CH2-SiR 1 a X 3-a (1) The condensation reactivity of the reactive silyl group is significantly increased by the sulfur atom being bonded to the carbon atom adjacent to the silicon atom. Therefore, the organic polymer having the reactive silyl group represented by the general formula (1) exhibits excellent fast curing properties even in a curable composition containing a low-activity silanol condensation catalyst.

[0019] R 1 represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. Here, the number of carbon atoms is preferably 1 to 10, more preferably 1 to 8, even more preferably 1 to 6, still more preferably 1 to 3, and particularly preferably 1 or 2. When the hydrocarbon group has a substituent, the substituent is not particularly limited, and examples thereof include halogen groups such as a chloro group, alkoxy groups such as a methoxy group, and amino groups such as an N,N-diethylamino group.

[0020] R 1 Examples of the R include unsubstituted alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-hexyl, 2-ethylhexyl, and n-dodecyl; substituted alkyl groups such as chloromethyl, methoxymethyl, and N,N-diethylaminomethyl; unsaturated hydrocarbon groups such as vinyl, isopropenyl, and allyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, toluyl, and 1-naphthyl; and aralkyl groups such as benzyl. R is preferably a substituted or unsubstituted alkyl group, more preferably a methyl group, ethyl group, chloromethyl group, or methoxymethyl group, even more preferably a methyl group or methoxymethyl group, and particularly preferably a methyl group. 1 As the alkyl group, only one type of group may be used, or two or more types of groups may be used in combination.

[0021] X represents a hydroxyl group or a hydrolyzable group. Examples of X include a hydroxyl group, hydrogen, halogen, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. The alkoxy group may have a substituent. Since it is mildly hydrolyzable and easy to handle, an alkoxy group is preferable, a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group are more preferable, a methoxy group and an ethoxy group are further preferable, and a methoxy group is particularly preferable. As X, only one type of group may be used, or two or more types of groups may be used in combination.

[0022] In the general formula (1), a is 0, 1 or 2. Preferably, it is 0 or 1. In terms of the balance between the curability of the organic polymer and the physical properties of the cured product, it is more preferably 1.

[0023] -SiR in general formula (1) 1 a X 3-aExamples of the silyl group include a trimethoxysilyl group, a triethoxysilyl group, a tris(2-propenyloxy)silyl group, a triacetoxysilyl group, a methyldimethoxysilyl group, a methyldiethoxysilyl group, a dimethoxyethylsilyl group, a (chloromethyl)dimethoxysilyl group, a (chloromethyl)diethoxysilyl group, a (methoxymethyl)dimethoxysilyl group, a (methoxymethyl)diethoxysilyl group, a (N,N-diethylaminomethyl)dimethoxysilyl group, a (N,N-diethylaminomethyl)diethoxysilyl group, etc. Among them, a methyldimethoxysilyl group, a trimethoxysilyl group, a triethoxysilyl group, a (chloromethyl)dimethoxysilyl group, a (methoxymethyl)dimethoxysilyl group, a (methoxymethyl)diethoxysilyl group, a (N,N-diethylaminomethyl)dimethoxysilyl group, etc. are mentioned. From the viewpoint of reactivity, trimethoxysilyl group, (chloromethyl)dimethoxysilyl group, and (methoxymethyl)dimethoxysilyl group are more preferable. From the viewpoint of stability, methyldimethoxysilyl group, methyldiethoxysilyl group, and triethoxysilyl group are more preferable. In addition, trimethoxysilyl group, triethoxysilyl group, and methyldimethoxysilyl group are more preferable because they are easy to produce. Among them, methyldimethoxysilyl group is the most preferable.

[0024] The number of reactive silyl groups contained in one molecule of the organic polymer is preferably 0.5 or more, more preferably 1.0 or more, and even more preferably 1.2 or more on average, and is preferably 4 or less, more preferably 3 or less.

[0025] In the organic polymer, the terminal structure having a reactive silyl group is not particularly limited, but a representative example is the terminal structure represented by the following general formula (4).

[0026] -OR 3 -CH(R 4 )-CH2-S-CH2-SiR 1 a X 3-a (4) In general formula (4), R 3represents a direct bond or a divalent hydrocarbon group having 1 to 4 carbon atoms; R 4 represents hydrogen or an alkyl group having 1 to 6 carbon atoms. The oxygen atom at the left end represents the oxygen atom bonded to the polymer skeleton. R 1 , X, and a are the same as defined above for general formula (1).

[0027] R 3 is preferably a divalent hydrocarbon group having 1 to 3 carbon atoms, more preferably a divalent hydrocarbon group having 1 to 2 carbon atoms. As the hydrocarbon group, an alkylene group is preferred, and a methylene group, ethylene group, propylene group, or butylene group can be used. A methylene group is particularly preferred.

[0028] R 4 R is preferably hydrogen or an alkyl group having 1 to 4 carbon atoms, more preferably hydrogen or an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group include hydrogen, a methyl group, an ethyl group, a propyl group, and a butyl group. 4 is preferably hydrogen, a methyl group, or an ethyl group, and more preferably hydrogen or a methyl group. In particular, R 4 is preferably a methyl group.

[0029] <Main chain structure> The main chain structure of the organic polymer may be linear or may have a branched chain. The main chain skeleton of the organic polymer is not particularly limited, and various main chain skeletons can be used.Specific examples of the main chain skeleton include polyoxyalkylene polymers such as polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymers, and polyoxypropylene-polyoxybutylene copolymers; ethylene-propylene copolymers, polyisobutylene, copolymers of isobutylene and isoprene, etc., polychloroprene, polyisoprene, copolymers of isoprene or butadiene and acrylonitrile and / or styrene, etc., copolymers of polybutadiene, isoprene or butadiene and acrylonitrile and styrene, etc., and polyolefin polymers thereof. Examples of the organic polymers include saturated hydrocarbon polymers such as hydrogenated polyolefin polymers obtained by hydrogenating a polymer; polyester polymers; vinyl polymers such as (meth)acrylic acid ester polymers obtained by radical polymerization of (meth)acrylic acid ester monomers such as ethyl (meth)acrylate and butyl (meth)acrylate, and polymers obtained by radical polymerization of monomers such as (meth)acrylic acid monomers, vinyl acetate, acrylonitrile, and styrene; graft polymers obtained by polymerizing vinyl monomers in the above-mentioned polymers; polysulfide polymers; polyamide polymers; polycarbonate polymers; and diallyl phthalate polymers. The above-mentioned polymers may be mixed in block form, graft form, etc. Among these, saturated hydrocarbon polymers, polyoxyalkylene polymers, and (meth)acrylic acid ester polymers are preferred because they have a relatively low glass transition temperature and the obtained cured product has excellent cold resistance, polyoxyalkylene polymers are more preferred, and polyoxypropylene is particularly preferred.

[0030] The organic polymer may be a polymer having any one of the above-mentioned various main chain skeletons, or a mixture of polymers having different main chain skeletons. The mixture may be a mixture of polymers produced separately, or may be a mixture produced simultaneously to have an arbitrary mixture composition.

[0031] The number average molecular weight of the organic polymer is not particularly limited, but is preferably 3,000 to 100,000, more preferably 3,000 to 50,000, and even more preferably 3,000 to 30,000 in terms of polystyrene equivalent molecular weight in GPC. When the number average molecular weight is 3,000 or more, the relative amount of reactive silyl groups to the entire polymer is in an appropriate range, which is desirable in terms of production costs. Also, when the number average molecular weight is 100,000 or less, it is easy to achieve a desirable viscosity in terms of workability. The number average molecular weight can be determined in terms of polystyrene equivalent by GPC measurement.

[0032] The molecular weight distribution (Mw / Mn) of the organic polymer is not particularly limited, but is preferably narrow. Specifically, it is preferably less than 2.0, more preferably 1.6 or less, even more preferably 1.5 or less, and particularly preferably 1.4 or less. The molecular weight distribution (Mw / Mn) can be calculated from the number average molecular weight and weight average molecular weight calculated in terms of polystyrene by GPC measurement.

[0033] <Method of producing organic polymer> Next, a method for producing the organic polymer will be described. Although the production method is not particularly limited, for example, the organic polymer can be produced by introducing a carbon-carbon double bond into a hydroxyl group-containing organic polymer by utilizing the reactivity of the hydroxyl group, and then reacting the polymer with a compound having a reactive silyl group and a mercapto group.

[0034] (Polyoxyalkylene polymer) Hereinafter, an embodiment of the method for producing the organic polymer will be described in detail for the case where the polymer skeleton of the organic polymer is a polyoxyalkylene-based polymer, but the method for producing the organic polymer is not limited to the following description.

[0035] (polymerization) The polymer backbone of the polyoxyalkylene polymer can be formed by polymerizing an epoxy compound with an initiator having a hydroxyl group by a conventionally known method, thereby obtaining a hydroxyl-terminated polyoxyalkylene polymer. Although the specific polymerization method is not particularly limited, a polymerization method using a composite metal cyanide complex catalyst such as zinc hexacyanocobaltate glyme complex is preferred because it can obtain a hydroxyl-terminated polymer with a small molecular weight distribution (Mw / Mn).

[0036] The initiator having a hydroxyl group is not particularly limited, and examples thereof include organic compounds having one or more hydroxyl groups, such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, low molecular weight polyoxypropylene glycol, low molecular weight polyoxypropylene triol, allyl alcohol, low molecular weight polyoxypropylene monoallyl ether, and low molecular weight polyoxypropylene monoalkyl ether.

[0037] The epoxy compound is not particularly limited, but examples thereof include alkylene oxides such as ethylene oxide and propylene oxide, and glycidyl ethers such as methyl glycidyl ether and butyl glycidyl ether, etc. Propylene oxide is preferred.

[0038] (Reaction with alkali metal salts) When introducing a carbon-carbon double bond into a hydroxyl-terminated polyoxyalkylene polymer, it is preferable to first react an alkali metal salt with the hydroxyl-terminated polyoxyalkylene polymer to convert the terminal hydroxyl groups into metaloxy groups. Alternatively, a composite metal cyanide complex catalyst can be used in place of the alkali metal salt. In this manner, a metaloxy-terminated polyoxyalkylene polymer is formed.

[0039] The alkali metal salt is not particularly limited, and examples thereof include sodium hydroxide, sodium alkoxide, potassium hydroxide, potassium alkoxide, lithium hydroxide, lithium alkoxide, cesium hydroxide, and cesium alkoxide. From the viewpoint of ease of handling and solubility, sodium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium hydroxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide are preferred, and sodium methoxide and sodium tert-butoxide are more preferred. From the viewpoint of availability, sodium methoxide is particularly preferred, and from the viewpoint of reactivity, sodium tert-butoxide is particularly preferred. The alkali metal salt may be dissolved in a solvent and then subjected to the reaction.

[0040] The amount of the alkali metal salt used is not particularly limited, but the molar ratio to the hydroxyl groups of the hydroxyl-terminated polyoxyalkylene polymer is preferably 0.5 or more, more preferably 0.6 or more, even more preferably 0.7 or more, and even more preferably 0.8 or more. The molar ratio is preferably 1.2 or less, and more preferably 1.1 or less. When the alkali metal salt is used within the above-mentioned range, the conversion reaction of the hydroxyl groups to the metaloxy groups can be easily and sufficiently progressed, and it is possible to prevent the alkali metal salt from remaining as an impurity and causing a side reaction.

[0041] The alkali metal salt is used to convert the hydroxyl group of the hydroxyl-terminated polyoxyalkylene polymer to a metaloxy group, and in order to efficiently proceed with this conversion reaction, it is preferable to remove moisture and substances having hydroxyl groups other than the polyoxyalkylene polymer from the reaction system in advance. To remove them, a known method may be used, for example, heating evaporation, reduced pressure devolatilization, spray evaporation, thin film evaporation, azeotropic devolatilization, etc.

[0042] The temperature for reacting with the alkali metal salt can be appropriately set by those skilled in the art, but is preferably from 50° C. to 150° C., and more preferably from 110° C. to 145° C. The time for reacting with the alkali metal salt is preferably from 10 minutes to 5 hours, and more preferably from 30 minutes to 3 hours.

[0043] (Reaction with electrophiles) By reacting an electrophilic agent having a carbon-carbon double bond with the metaloxy group-terminated polyoxyalkylene polymer obtained as described above, the metaloxy group can be converted into a structure containing a carbon-carbon double bond, thereby forming a polyoxyalkylene polymer having a carbon-carbon double bond in the terminal structure.

[0044] The electrophilic agent having a carbon-carbon double bond is not particularly limited as long as it is a compound that can react with the metaloxy group of the polyoxyalkylene polymer to introduce a carbon-carbon double bond into the polyoxyalkylene polymer. Examples of the electrophilic agent include organic halides having a carbon-carbon double bond.

[0045] The organic halide having a carbon-carbon double bond reacts with the metaloxy group through a halogen substitution reaction to form an ether bond, and a structure containing a carbon-carbon double bond can be introduced as a terminal structure of the polyoxyalkylene polymer. The organic halide having a carbon-carbon double bond can be, but is not limited to, a compound represented by the following general formula (3): ZR 3 -C(R 4 )=CH2(3) In the general formula (3), R 3 and R 4 are the same as those described above for general formula (4), 3 and R 4 Z represents a halogen atom. When a reactive silyl group, which will be described later, is introduced into a polyoxyalkylene polymer having a carbon-carbon double bond in a terminal structure obtained by reacting the organic halide, a terminal structure represented by the general formula (4) can be formed.

[0046] Specific examples of organic halides having a carbon-carbon double bond include, but are not limited to, vinyl chloride, allyl chloride, methallyl chloride, vinyl bromide, allyl bromide, methallyl bromide, vinyl iodide, allyl iodide, methallyl iodide, etc. Allyl chloride and methallyl chloride are preferred from the viewpoint of ease of handling. Furthermore, methallyl chloride, methallyl bromide, and methallyl iodide are preferred from the viewpoint of improving the introduction rate of the reactive silyl group.

[0047] The amount of the organic halide having a carbon-carbon double bond to be added is not particularly limited, but the molar ratio of the organic halide to the hydroxyl groups of the polyoxyalkylene polymer is preferably 0.7 or more, more preferably 1.0 or more, and the molar ratio is preferably 5.0 or less, more preferably 2.0 or less.

[0048] The temperature when reacting the metaloxy group-terminated polyoxyalkylene polymer with an organic halide having a carbon-carbon double bond is preferably from 50° C. to 150° C., more preferably from 110° C. to 140° C. The reaction time is preferably from 10 minutes to 5 hours, more preferably from 30 minutes to 3 hours.

[0049] (Introduction of reactive silyl groups) The polyoxyalkylene polymer having a carbon-carbon double bond in the terminal structure obtained as above can be reacted with a compound having a reactive silyl group and a mercapto group in one molecule (hereinafter also referred to as a mercapto group-containing compound) to form a sulfide bond by an addition reaction of the mercapto group to the carbon-carbon double bond, thereby introducing a reactive silyl group into the polymer. This allows the production of an organic polymer having a reactive silyl group represented by general formula (1).

[0050] The mercapto group-containing compound is represented by the following general formula (2): HS-CH2-SiR 1 a X 3-a (2) In the general formula (2), R 1 , X, and a are the same as those described above for the general formula (1). Specific examples of the mercapto group-containing compound include (mercaptomethyl)methyldimethoxysilane, (mercaptomethyl)trimethoxysilane, (mercaptomethyl)methyldiethoxysilane, and (mercaptomethyl)triethoxysilane.

[0051] The amount of the mercapto group-containing compound used may be appropriately determined in consideration of the amount of carbon-carbon double bonds in the polyoxyalkylene polymer. Specifically, the amount of the compound used relative to the carbon-carbon double bonds in the polyoxyalkylene polymer is 0.6 molar times or more, and from the viewpoint of further increasing the reactive silyl group introduction rate, it is preferably 1.0 molar times or more, more preferably 1.2 molar times or more, even more preferably 1.5 molar times or more, and particularly preferably more than 1.5 molar times. The upper limit of the amount of the mercapto group-containing compound used is not particularly limited, and is preferably 5 molar times or less, more preferably 3 molar times or less.

[0052] The addition reaction of a mercapto group to a carbon-carbon double bond may be carried out in the presence of a radical initiator in order to increase the reaction rate or improve the reaction rate. As such a radical initiator, a conventionally known initiator can be used. Specific examples include, but are not limited to, azo initiators and peroxide initiators.

[0053] Among known radical initiators, catalysts with low activity toward reactive silyl groups are preferred. From this viewpoint, azo initiators such as 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (V-59), and 2,2'-azobis(1-methylcyclohexanecarbonitrile) (V-40) are particularly preferred.

[0054] The radical initiator may be added in portions or continuously to the reaction system containing the organic polymer having a carbon-carbon double bond and the mercapto group-containing compound, rather than being added all at once. By adopting such an addition method, the reactive silyl group introduction rate of 60% or more can be achieved. When the radical initiator is added in portions, the number of additions is preferably two or more, more preferably three or more, and even more preferably four or more. It is desirable to carry out each addition with an interval of, for example, 10 minutes or more, preferably 30 minutes or more. When the radical initiator is added continuously, it is desirable to carry out the addition over a period of, for example, 1 hour or more, preferably 2 hours or more. The radical initiator may be added in a state dissolved in an organic solvent.

[0055] The total amount of radical initiator used can be appropriately set by those skilled in the art, but from the viewpoint of further increasing the reactive silyl group introduction rate, it is preferably 0.15 parts by weight or more relative to 100 parts by weight of the organic polymer, more preferably 0.2 parts by weight or more, even more preferably 0.3 parts by weight or more, and particularly preferably 0.4 parts by weight or more. Furthermore, from the viewpoint of suppressing residues derived from the initiator and controlling reaction heat in addition to improving the reactive silyl group introduction rate, the total amount of radical initiator used is preferably 0.15 to 10 parts by weight relative to 100 parts by weight of the organic polymer, more preferably 0.2 to 10 parts by weight, even more preferably 0.3 to 5 parts by weight, and particularly preferably 0.4 to 3 parts by weight.

[0056] The temperature of the addition reaction can be appropriately set by those skilled in the art, but is preferably 50°C to 120°C, more preferably 70°C to 100°C. The reaction time may also be appropriately set, but it is preferable to adjust the reaction time together with the temperature conditions so that unintended condensation reaction between polymers does not proceed. Specifically, the reaction time is preferably 15 minutes to 10 hours, more preferably 30 minutes to 6 hours.

[0057] ((Meth)acrylic acid ester polymer) When the main chain of the organic polymer is a (meth)acrylic acid ester polymer, examples of the method for producing the organic polymer include: (I) a method in which a compound having a polymerizable unsaturated group and a reactive functional group (e.g., acrylic acid, 2-hydroxyethyl acrylate) is copolymerized with a monomer having a (meth)acrylic structure to obtain a polymer, and then a carbon-carbon double bond is introduced into any position (preferably the molecular chain terminal) of the obtained polymer, and then the mercapto group-containing compound is added to the carbon-carbon double bond; and (II) a method in which a monomer having a (meth)acrylic structure is polymerized by a living radical polymerization method such as atom transfer radical polymerization to obtain a polymer, and then a carbon-carbon double bond is introduced into any position (preferably the molecular chain terminal) of the obtained polymer, and then the mercapto group-containing compound is added to the carbon-carbon double bond.

[0058] (Saturated Hydrocarbon Polymer) When the main chain of the organic polymer is a saturated hydrocarbon polymer, examples of the method for producing the organic polymer include a method in which an olefin compound having 2 to 6 carbon atoms, such as ethylene, propylene, 1-butene, or isobutylene, is polymerized as a main monomer to obtain a polymer, and then a carbon-carbon double bond is introduced into any position (preferably the molecular chain terminal) of the obtained polymer, and then the mercapto group-containing compound is added to the carbon-carbon double bond.

[0059] The organic polymer of the present invention can be synthesized by the above steps. The organic polymer after synthesis is preferably heated under reduced pressure to distill off unreacted materials or by-products contained in the polymer. In particular, in order to remove the mercapto group-containing compound and disulfide bodies that may be generated by side reactions, it is preferable to carry out a step of distilling off volatile matters at a temperature of 100°C or higher under reduced pressure after the reaction with the mercapto group-containing compound. The temperature is more preferably 110°C or higher, even more preferably 120°C or higher, and most preferably 130°C or higher. By carrying out this step, an organic polymer with a reduced odor specific to sulfur compounds can be obtained.

[0060] <Curable composition> The present invention can provide a curable composition containing the organic polymer.

[0061] (Silanol condensation catalyst) The curable composition of the present invention preferably contains a silanol condensation catalyst for the purpose of promoting the reaction of hydrolysis and condensation of the reactive silyl groups, that is, the curing reaction.

[0062] As the silanol condensation catalyst, any of the conventionally known catalysts can be used. Specifically, an organic tin compound, a metal carboxylate, an amine compound, a carboxylic acid, an alkoxy metal, an inorganic acid, etc. can be used.

[0063] Specific examples of the organotin compound include dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin bis(butyl maleate), dibutyltin diacetate, dibutyltin oxide, dibutyltin bis(acetylacetonate), a reaction product of dibutyltin oxide and a silicate compound, a reaction product of dibutyltin oxide and a phthalic acid ester, dioctyltin diacetate, dioctyltin dilaurate, dioctyltin bis(ethyl maleate), dioctyltin bis(octyl maleate), dioctyltin bis(acetylacetonate), a reaction product of dioctyltin oxide and a silicate compound, and the like. In view of the recent increase in environmental interest, dioctyltin compounds are preferred. However, since the organic polymer of the present invention exhibits rapid curing properties, the curable composition of the present invention does not contain an organotin compound, and can contain a silanol condensation catalyst other than an organotin compound. Even if the curable composition of the present invention does not contain an organotin compound, it can exhibit good curing properties.

[0064] Specific examples of the metal carboxylate include tin carboxylate, bismuth carboxylate, titanium carboxylate, zirconium carboxylate, iron carboxylate, etc. The carboxylate group can be a combination of the following carboxylic acid with various metals.

[0065] Specific examples of the amine compound include amines such as octylamine, 2-ethylhexylamine, laurylamine, and stearylamine; nitrogen-containing heterocyclic compounds such as pyridine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), and 1,5-diazabicyclo[4,3,0]nonene-5 (DBN); guanidines such as guanidine, phenylguanidine, and diphenylguanidine; biguanides such as butylbiguanide, 1-o-tolylbiguanide, and 1-phenylbiguanide; and ketimine compounds.

[0066] Specific examples of carboxylic acids include acetic acid, propionic acid, butyric acid, 2-ethylhexanoic acid, lauric acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, and versatic acid.

[0067] Specific examples of alkoxy metals include titanium compounds such as tetrabutyl titanate titanium tetrakis(acetylacetonate) and diisopropoxy titanium bis(ethylacetoacetate), aluminum compounds such as aluminum tris(acetylacetonate) and diisopropoxyaluminum ethylacetoacetate, and zirconium compounds such as zirconium tetrakis(acetylacetonate).

[0068] Other silanol condensation catalysts that can be used include fluorine anion-containing compounds, photoacid generators, and photobase generators.

[0069] The silanol condensation catalyst may be a combination of two or more different catalysts. For example, the combination of the above-mentioned amine compound and carboxylic acid may provide an effect of improving reactivity.

[0070] In addition, since the reactive silyl group of the organic polymer of the present invention has high activity, it is possible to reduce the amount of the curing catalyst, use a curing catalyst with low activity, or use aminosilane, an amino group-containing silane coupling agent, as the curing catalyst. Since aminosilane is usually added as an adhesion imparting agent, when aminosilane is used as the curing catalyst, a curable composition can be prepared without using a curing catalyst that is usually used. Therefore, it is preferable not to add other curing catalysts. In particular, when the reactive silyl group contains a trimethoxysilyl group or a methoxymethyldimethoxysilyl group, excellent curability is exhibited even when only aminosilane is used as the curing catalyst.

[0071] The amount of the silanol condensation catalyst is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, and particularly preferably 0.01 to 10 parts by weight, relative to 100 parts by weight of the organic polymer of the present invention. If the amount of the silanol condensation catalyst is less than 0.001 parts by weight, the reaction rate may be insufficient. On the other hand, if the amount of the silanol condensation catalyst is more than 20 parts by weight, the reaction rate is too fast, so the usable time of the composition is shortened, which tends to result in poor workability and poor storage stability. Furthermore, some silanol condensation catalysts may seep onto the surface of the cured product after the curable composition is cured, or may contaminate the surface of the cured product. In such cases, the amount of the silanol condensation catalyst used is 0.01 to 3.0 parts by weight, so that the surface condition of the cured product can be maintained good while ensuring the curability.

[0072] The curable composition of the present invention may contain other additives such as silicon compounds, adhesion promoters, plasticizers, solvents, diluents, silicates, fillers, sagging inhibitors, antioxidants, light stabilizers, ultraviolet absorbers, physical property regulators, tackifier resins, compounds containing epoxy groups, photocurable substances, oxygen curable substances, surface property improvers, epoxy resins, other resins, flame retardants, and foaming agents. In addition, the curable composition of the present invention may contain various additives as necessary for the purpose of adjusting the various physical properties of the composition or the cured product. Examples of such additives include, for example, curability regulators, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, and fungicides.

[0073] <<Preparation of Curable Composition>> The curable composition of the present invention can be prepared as a one-component type in which all ingredients are mixed in advance and stored in a sealed state, and then cured by moisture in the air after application, or as a two-component type in which ingredients such as a silanol condensation catalyst, a filler, a plasticizer, and water are mixed separately as a curing agent, and the ingredients are mixed with the organic polymer composition before use. From the viewpoint of workability, the one-component type is preferred.

[0074] When the curable composition is of one-component type, all the components are mixed in advance, and therefore, it is preferable to use the components containing water after dehydration and drying in advance, or to dehydrate them by reducing pressure during mixing and kneading. In addition to the dehydration and drying method, the storage stability can be further improved by adding an alkoxysilane compound such as n-propyltrimethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, or γ-glycidoxypropyltrimethoxysilane.

[0075] <Application> The curable composition of the present invention can be used as an adhesive, a sealing material for buildings, ships, automobiles, roads, etc., an adhesive, a waterproofing material, a coating waterproofing material, a mold release agent, an anti-vibration material, a vibration-damping material, a sound-proofing material, a foaming material, a paint, a spraying material, etc. The cured product obtained by curing the curable composition of the present invention is excellent in flexibility and adhesiveness, and therefore can be suitably used as a sealing material or adhesive.

[0076] The curable composition of the present invention can be used in a wide range of applications, including electrical and electronic component materials such as a sealing material for the back surface of a solar cell, electrical insulating materials for electrical and electronic components and devices such as insulating coating materials for electric wires and cables, acoustic insulating materials, elastic adhesives, binders, contact adhesives, spray-type sealants, crack repair materials, tiling adhesives, adhesives for asphalt waterproofing materials, powder coatings, casting materials, medical rubber materials, medical adhesives, medical adhesive sheets, medical device sealants, dental impression materials, food packaging materials, and joint sealants for exterior materials such as sizing boards. It can be used for various applications such as coating materials, anti-slip coating materials, buffer materials, primers, conductive materials for electromagnetic wave shielding, thermally conductive materials, hot melt materials, potting agents for electrical and electronic devices, films, gaskets, concrete reinforcing materials, temporary adhesives, various molding materials, and sealing materials for rust prevention and waterproofing of wired glass and laminated glass end faces (cut parts), liquid sealants used in automobile parts, large vehicle parts such as trucks and buses, train car parts, aircraft parts, ship parts, electrical parts, various machine parts, etc. For example, in automobiles, it can be used in a wide variety of applications such as adhesive installation of plastic covers, trims, flanges, bumpers, window mounting, interior parts, exterior parts, etc. Furthermore, since it can adhere to a wide range of substrates such as glass, porcelain, wood, metal, resin moldings, etc., either alone or with the help of a primer, it can also be used as various types of sealing compositions and adhesive compositions. The curable composition of the present invention can also be used as an adhesive for interior panels, exterior panels, tile adhesives, stone veneers, ceiling finish adhesives, floor finish adhesives, wall finish adhesives, vehicle panels, electrical / electronic / precision equipment assembly adhesives, adhesives for bonding leather, textile products, fabrics, paper, boards and rubber, reactive post-crosslinking pressure-sensitive adhesives, direct glazing sealants, double-glazing sealants, SSG construction sealants, or building working joint sealants, civil engineering and bridge materials. It can also be used as an adhesive material such as an adhesive tape or adhesive sheet. EXAMPLES

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0078] The number average molecular weight in the examples is a GPC molecular weight measured under the following conditions. Liquid delivery system: Tosoh HLC-8220GPC Column: Tosoh TSKgel SuperH series Solvent: THF Molecular weight: Polystyrene equivalent Measurement temperature: 40℃

[0079] "Reactive silyl group introduction rate" refers to the polyoxyalkylene polymer having a reactive silyl group. 1 H NMR was measured, and calculation was performed using the integral value of the signal indicating each group based on the formula: 100 × (number of moles of reactive silyl groups) / (total number of moles of reactive silyl groups, number of moles of groups to which a reactive silyl group can be introduced (allyl groups in this example) that remained without the reactive silyl group being introduced, and number of moles of groups to which the reactive silyl group can be introduced (1-propenyl groups in this example) that were isomerized).

[0080] (Synthesis example) Using polyoxypropylene diol with a number average molecular weight of about 4,500 as an initiator, propylene oxide was polymerized with zinc hexacyanocobaltate glyme complex to obtain polyoxypropylene with a number average molecular weight of 15,000 having hydroxyl groups at the terminals. Next, a methanol solution of sodium methoxide in an amount of 1.2 equivalents relative to the hydroxyl groups of this polyoxypropylene was added, methanol was distilled off, and 1.5 equivalents of 3-chloro-1-propene were added to convert the terminal hydroxyl groups to allyl groups, thereby obtaining polyoxypropylene (A-1).

[0081] Example 1 In a glass reactor equipped with a stirrer, reflux condenser, and thermometer, 2.5 parts by weight of hexane was added to 100 parts by weight of polymer (A-1), and azeotropic dehydration was carried out at 90°C. The hexane was distilled off under reduced pressure and replaced with nitrogen. At 90°C, 5.64 parts by weight of mercaptomethyltrimethoxysilane (1.51 molar times the terminal allyl group) and 0.1 part by weight of 2,2'-azobis(2-methylbutyronitrile) as a radical initiator were added to initiate the reaction. 1, 2, and 3 hours after the start of the reaction, 0.1 parts by weight each of 2,2'-azobis(2-methylbutyronitrile) were added. In other words, the initiator was added in four separate portions. 4 hours after the start of the reaction, 1 The termination of the reaction was confirmed by H-NMR measurement, and the mercaptomethyltrimethoxysilane remaining in the polymer and by-products derived from mercaptomethyltrimethoxysilane were distilled off under reduced pressure at 130° C. 1 H-NMR measurement confirmed the disappearance of the signals of mercaptomethyltrimethoxysilane and by-products derived from mercaptomethyltrimethoxysilane. The obtained reaction product was a polyoxypropylene with a number average molecular weight of 15,000 and a terminal (trimethoxysilylmethyl)sulfanyl group, with a reduced odor characteristic of sulfur compounds. The introduction rate of reactive silyl groups in the polymer was 94.5%.

[0082] Example 2 In a glass reactor equipped with a stirrer, reflux condenser, and thermometer, 2.5 parts by weight of hexane was added to 100 parts by weight of polymer (A-1), and azeotropic dehydration was carried out at 90°C. The hexane was distilled off under reduced pressure and replaced with nitrogen. At 90°C, 5.64 parts by weight of mercaptomethyltrimethoxysilane (1.51 molar times the terminal allyl group) and 0.1 part by weight of 2,2'-azobis(2-methylbutyronitrile) as a radical initiator were added to initiate the reaction. 1, 2, 3, 4, and 5 hours after the start of the reaction, 0.1 parts by weight each of 2,2'-azobis(2-methylbutyronitrile) were added. In other words, the initiator was added in six separate portions. 6 hours after the start of the reaction, 1The termination of the reaction was confirmed by H-NMR measurement, and the mercaptomethyltrimethoxysilane remaining in the polymer and by-products derived from mercaptomethyltrimethoxysilane were distilled off under reduced pressure at 130° C. 1 H-NMR measurement confirmed the disappearance of the signals of mercaptomethyltrimethoxysilane and by-products derived from mercaptomethyltrimethoxysilane. The obtained reaction product was a polyoxypropylene with a number average molecular weight of 15,000 and a terminal (trimethoxysilylmethyl)sulfanyl group, with a reduced odor characteristic of sulfur compounds. The introduction rate of reactive silyl groups in the polymer was 96.0%.

[0083] Example 3 In a glass reactor equipped with a stirrer, reflux condenser, and thermometer, 2.5 parts by weight of hexane was added to 100 parts by weight of polymer (A-1), and azeotropic dehydration was carried out at 90°C. The hexane was distilled off under reduced pressure and replaced with nitrogen. At 90°C, 7.48 parts by weight of mercaptomethyltrimethoxysilane (2.00 molar times the terminal allyl group) and 0.1 part by weight of 2,2'-azobis(2-methylbutyronitrile) as a radical initiator were added to initiate the reaction. 2, 4, and 5 hours after the start of the reaction, 0.1 parts by weight each of 2,2'-azobis(2-methylbutyronitrile) were added. In other words, the initiator was added in four separate portions. 4 hours after the start of the reaction, 1 The termination of the reaction was confirmed by H-NMR measurement, and the mercaptomethyltrimethoxysilane remaining in the polymer and by-products derived from mercaptomethyltrimethoxysilane were distilled off under reduced pressure at 130° C. 1 H-NMR measurement confirmed the disappearance of the signals of mercaptomethyltrimethoxysilane and by-products derived from mercaptomethyltrimethoxysilane. The obtained reaction product was a polyoxypropylene with a number average molecular weight of 15,000 and a terminal (trimethoxysilylmethyl)sulfanyl group, with a reduced odor characteristic of sulfur compounds. The introduction rate of reactive silyl groups in the polymer was over 99.0%. 100 parts by weight of the obtained polymer and 1 part by weight of 3-aminopropyltrimethoxysilane (A-1110) were weighed into a mini cup, then kneaded and stirred, and allowed to stand under constant temperature and humidity conditions of 23°C and 50%. The surface of the mixture was touched with a spatula, and the time it took for the mixture to no longer adhere to the spatula was measured as the skinning time, which was 20 minutes.

[0084] Comparative Example 1 Into a glass reactor equipped with a stirrer, a reflux condenser, and a thermometer, 100 parts by weight of polymer (A-1) and 3.74 parts by weight of mercaptomethyltrimethoxysilane (1.00 molar equivalent relative to the terminal allyl group) were added and heated to 90° C. 0.1 parts by weight of 2,2′-azobis(2-methylbutyronitrile) was added and stirred for 3 hours. 1 The end of the reaction was confirmed by H-NMR measurement, and the pressure was reduced while the temperature was kept at 90°C, but the signals of mercaptomethyltrimethoxysilane and by-products derived from mercaptomethyltrimethoxysilane did not disappear. Although the odor was not sufficiently removed, the operation was terminated. A polyoxypropylene having a number average molecular weight of 15,000 and a (trimethoxysilylmethyl)sulfanyl group at the end was obtained. The reactive silyl group introduction rate in the polymer was 30.0%.

[0085] Comparative Example 2 Into a glass reactor equipped with a reflux condenser and a thermometer, 100 parts by weight of polymer (A-1) and 7.48 parts by weight of mercaptomethyltrimethoxysilane (2.00 times by mole relative to the terminal allyl group) were added and heated to 90° C. 0.1 parts by weight of 2,2′-azobis(2-methylbutyronitrile) was added and stirred for 3 hours. 1 The end of the reaction was confirmed by H-NMR measurement, and the pressure was reduced while the temperature was kept at 90°C, but the signals of mercaptomethyltrimethoxysilane and by-products derived from mercaptomethyltrimethoxysilane did not disappear. Although the odor was not sufficiently removed, the operation was terminated. A polyoxypropylene having a number average molecular weight of 15,000 and a (trimethoxysilylmethyl)sulfanyl group at the end was obtained. The reactive silyl group introduction rate in the polymer was 53.7%.

[0086] (Method for evaluating dumbbell tensile properties) 100 parts by weight of the polymer obtained in Examples 2 and 3, and Comparative Example 1 were mixed with 3.0 parts by weight of tin octylate, 0.5 parts by weight of laurylamine, and 0.6 parts by weight of water, stirred uniformly, and centrifuged to defoam the mixture, which was then filled into a polyethylene mold without introducing air bubbles, and aged at 23°C and 50% RH for 1 hour and then at 70°C for 20 hours to produce a sheet with a thickness of about 3 mm. The sheet was punched into a No. 3 dumbbell shape, and a tensile strength test was performed at 23°C and 50% RH to measure the stress at 30% elongation (M30). The tensile strength was measured at a pulling speed of 200 mm / min using an autograph (Shimadzu Corporation, AGS-J).

[0087] [Table 1]

[0088] As is clear from Table 1, in Examples 1 to 3 in which the radical initiator was added in portions when reacting the allyl-terminated polymer with the mercapto-group-containing compound, the reactive silyl group introduction rate of the resulting polymer was 90% or more, and the cured product of the polymer exhibited a high modulus value. Although the tensile properties were not evaluated in Example 1, since the reactive silyl group introduction rate was at the same level as in Examples 2 and 3, it is presumed that the modulus value will be similar to that of Examples 2 and 3.

[0089] On the other hand, in Comparative Example 1, in which the allyl group-terminated polymer and the mercapto group-containing compound were reacted by adding the radical initiator all at once in accordance with Example 1 of Patent Document 2, the reactive silyl group introduction rate was extremely low at 30.0%, and the modulus value also showed a lower value compared to Examples 2 and 3. In Comparative Example 2, in which the amount of the mercapto group-containing compound used was increased to twice that of Comparative Example 1, but the radical initiator was added all at once, the reactive silyl group introduction rate was improved compared to Comparative Example 1, but was still low compared to Examples 1 to 3. From this, it can be seen that in order to sufficiently increase the reactive silyl group introduction rate, it is not enough to simply increase the amount of the mercapto group-containing compound used, and it is preferable to add the radical initiator in portions.

Claims

1. The following general formula (1): -S-CH ２ -SiR １ ａ X ３－ａ (1) (In the formula, R １ represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. X represents a hydroxyl group or a hydrolyzable group. a is 0, 1 or 2. R １ or when a plurality of X's are present, they may be the same or different; the polymer backbone of the organic polymer is a polyoxyalkylene polymer, An organic polymer having a carbon-carbon double bond and a compound represented by the following general formula (2): HS-CH ２ -SiR １ ａ X ３－ａ (2) (In the formula, R １ , X, and a are the same as defined above.) in the presence of a radical initiator, the reaction is carried out while adding the radical initiator in portions or continuously to a system containing the organic polymer having a carbon-carbon double bond and the mercapto group-containing compound.

2. 2. The method according to claim 1, wherein the amount of the mercapto group-containing compound used is 1.2 molar times or more relative to the carbon-carbon double bond.

3. 2. The method according to claim 1, wherein the amount of the mercapto group-containing compound used is 1.5 molar times or more relative to the carbon-carbon double bond.

4. The method according to any one of claims 1 to 3, wherein the total amount of the radical initiator used is 0.2 parts by weight or more based on 100 parts by weight of the organic polymer having a carbon-carbon double bond.

5. The method according to any one of claims 1 to 3, wherein the total amount of the radical initiator used is 0.4 parts by weight or more based on 100 parts by weight of the organic polymer having a carbon-carbon double bond.

6. The method according to any one of claims 1 to 5, further comprising the step of distilling off volatile matters under reduced pressure at a temperature of 130°C or higher after the reaction.

7. The method according to any one of claims 1 to 6, wherein the organic polymer has a reactive silyl group introduction rate of 80% or more.

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