JP2020117583A - Curable composition - Google Patents

Abstract

To provide a curable composition which provides a cured material having excellent physical property such as followability to an adherend and elongation and can be suppressed in deterioration of curability after storage at high temperature.SOLUTION: The curable composition is provided that includes: a polymer which has two or more main chain end groups in one molecule, over 0.5 of reactive silicon group on average in one molecule, and has a number average molecular weight of 10,000 to 60, 000; a tetravalent tin catalyst; and at least one kind of compound A selected from the group consisting of alkyl alcohol having 1 to 6 carbons, alkoxysilane having an alkoxy group having 1 to 4 carbons, monovalent carboxylic acid, a diketone compound represented by the following formula 2, wherein a content of the tetravalent tin catalyst relative to 100 pts.mass of the polymer is smaller than 1.0 pt.mass. R-C(O)-(CH)-C(O)-RFormula 2.SELECTED DRAWING: None

Description

The present invention relates to curable compositions.

A polymer having a reactive silicon group in its molecule has the property that even at room temperature, a cured product can be obtained by crosslinking due to the formation of a siloxane bond accompanied by a hydrolysis reaction of the reactive silicon group due to moisture and the like. It has been known.

The polymer having these reactive silicon groups is cured by a hydrolysis reaction to form a flexible rubber-like cured product.
Curable compositions containing such polymers are widely used as sealing materials, adhesives, coating agents and the like.

Among these polymers having a reactive silicon group, the main chain skeleton is an oxyalkylene polymer, a saturated hydrocarbon polymer, an acrylic acid alkyl ester polymer, and a methacrylic acid alkyl ester polymer, which have already been industrially produced. It is widely used for sealing materials, adhesives, paints, etc. When a curable composition containing a polymer having these reactive silicon groups is used as a sealing material, in addition to curability, adhesion to adherends, and elongation property of the cured product, it is exposed to an outdoor environment for a long time. It is required that the structure has resilience that can follow the structural expansion and contraction of joints caused by cracking and that cracks are less likely to occur.

Patent Document 1 describes a curable composition containing 5 parts by mass of dibutyltin dilaurate, which is a tetravalent tin catalyst, per 100 parts by mass of a polyoxyalkylene polymer having a reactive silicon group in the molecule. There is. The cured product obtained by curing the curable composition has good adhesiveness to an adherend but poor restorability. It is considered that this decrease in the restorability is due to the tetravalent tin catalyst used as the catalyst being incorporated into the structure of the cured product.

International Publication No. 2000/56817

The present inventors examined the content of a tetravalent tin catalyst with respect to the polymer in the curable composition for the purpose of improving the restoration of the cured product, and found that the content of the tetravalent tin catalyst was reduced. Therefore, it was found that excellent restoring property can be obtained.

On the other hand, when the content of the tetravalent tin catalyst is reduced, the time required for curing the curable composition after storage at high temperature (for example, 70° C. for 1 week) becomes much longer than that before storage. It was found that the curability of the curable composition was reduced. When the curable composition is used as a sealing material, if a long time is required for curing after the sealing material is applied, there is a problem that it cannot be transferred to the next step.

The present invention has been made in view of the above circumstances, the following properties of the cured product to the adherend, the physical properties of the cured product such as elongation of the cured product are good, and the curability decreases even after storage at high temperature. It is an object to provide a curable composition that suppresses.

The present invention has the following aspects.
[1] Having two or more main chain terminal groups in one molecule and having an average of more than 0.5 reactive silicon groups represented by the following formula 1 in one molecule and having a number average molecular weight of 10 2,000 to 60,000 polymer, tetravalent tin catalyst, alkyl alcohol having 1 to 6 carbon atoms, alkoxysilane having an alkoxy group having 1 to 4 carbon atoms, monovalent carboxylic acid, and the following formula And at least one compound A selected from the group consisting of diketones represented by 2, and the content of the tetravalent tin catalyst is less than 1.0 part by mass with respect to 100 parts by mass of the polymer, Curable composition.
—SiX _a R ¹ _3-a Formula 1
[In the formula, R ¹ represents a monovalent organic group having 1 to 20 carbon atoms and represents an organic group other than a hydrolyzable group, and X represents a hydroxyl group or a hydrolyzable group. a represents an integer of 1 to 3, and when a is 1, R ¹ may be the same or different, and when a is 2 or 3, X may be the same or different. ]
^{_{R 2 -C (O) - (}} CH 2) n -C (O) -R 3 Formula 2
[In the formula, n represents an integer of 1 to 6, and R ² and R ³ each independently represent an alkyl group having 1 to 20 carbon atoms. ]
[2] The curable composition according to [1], wherein the polymer contains at least one of an oxyalkylene polymer and a (meth)acrylic acid ester polymer.
[3] The curable composition according to [1] or [2], wherein the content ratio of the polymer in the curable composition is 1 to 80% by mass.
[4] The tetravalent tin catalyst according to any one of [1] to [3], which contains a tetravalent tin catalyst having a tetravalent tin atom and a residue of the compound A as constituent components. Curable composition.
[5] The curable composition according to any one of [1] to [4], wherein the content of the compound A is 100 to 2,500 mol with respect to 100 mol of the tetravalent tin catalyst.
[6] The curable composition according to any one of [1] to [5], wherein the compound A is at least one compound selected from the group consisting of methanol, tetraethoxysilane, acetic acid and acetylacetone. ..

According to the present invention, a curable composition which has good physical properties of a cured product such as conformability of the cured product to an adherend and elongation of the cured product, and which suppresses deterioration of the curability even after storage at high temperature. Obtainable.

The definitions and terms of the terms used in the present specification and claims are as follows.
The “main chain” refers to a polymer chain formed by linking two or more monomers. The “main chain” in the oxyalkylene polymer described later means a portion containing a residue of an initiator and a repeating unit based on an alkylene oxide monomer.
The “main chain end group” is an atom or an atomic group bonded to the terminal atom constituting the main chain.
The "active hydrogen-containing group" is at least one group selected from the group consisting of a hydroxyl group, a carboxy group, an amino group, a monovalent functional group obtained by removing a hydrogen atom from a primary amine, a hydrazide group and a sulfanyl group. That is.
The "active hydrogen" is a hydrogen atom based on the active hydrogen-containing group.
The "unsaturated group" is a monovalent group containing an unsaturated double bond, and unless otherwise specified, it is at least one group selected from the group consisting of a vinyl group, an allyl group and an isopropenyl group. That is.

The “oxyalkylene polymer” is a polymer whose main chain skeleton contains repeating units based on an alkylene oxide monomer.
The "precursor polymer" is a polymer before introduction of a reactive silicon group, and is an oxyalkylene polymer having a hydroxyl group as a main chain terminal group obtained by polymerizing an alkylene oxide monomer with active hydrogen of an initiator. Is.
"(Meth)acrylic acid alkyl ester polymer" means a polymer containing a repeating unit based on a (meth)acrylic acid alkyl ester monomer. The (meth)acrylic acid alkyl ester monomer means an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixture of both.
The “silylation rate” is the number of the reactive silicon groups with respect to the total number of the terminal groups which are any of reactive silicon groups, active hydrogen-containing groups and unsaturated groups in the main chain terminal groups of the oxyalkylene polymer. Is the ratio of. The value of the silylation rate can be measured by NMR analysis. Further, when the reactive silicon group is introduced into the terminal group in the main chain terminal group of the oxyalkylene polymer by the silylating agent described below, it can be represented by the charged equivalent amount of the silylating agent with respect to the number of terminal groups. ..
"Silylating agent" means a compound having a functional group that reacts with an active hydrogen-containing group or an unsaturated group, and a reactive silicon group.
The numerical range represented by "to" means a numerical range in which the numerical values before and after ~ are the lower limit value and the upper limit value.

The “number of end groups in the main chain end group” means, for example, the method of measuring iodine value defined in JIS K 0070 (1992) after introducing an unsaturated group into a precursor polymer of a polymer A described later. It is a value calculated by a method of directly measuring the concentration of unsaturated groups by a titration analysis based on the principle.
The “number of main chain terminal groups” in the oxyalkylene polymer described later is the same as the number of active hydrogen of the initiator described later or the number of main chain terminal groups of the precursor polymer described later.

The term “hydroxyl-converted molecular weight” means that, in the case of a polymer containing a repeating unit based on an alkylene oxide monomer, the hydroxyl value of an initiator or a precursor polymer is calculated based on JIS K 1557 (2007). , 100/(hydroxyl value)×(the number of active hydrogens of the initiator or the number of main chain terminal groups of the precursor polymer)”. The hydroxyl group-equivalent molecular weight of the oxyalkylene polymer tends to be equal to or slightly smaller than the oxyalkylene polymer-equivalent molecular weight described later.

In the present specification, "number average molecular weight" (hereinafter referred to as "Mn") and "weight average molecular weight" (hereinafter referred to as "Mw") mean tetrahydrofuran (hereinafter referred to as "THF") as an eluent. It is the oxyalkylene polymer-equivalent molecular weight measured by using a gel permeation chromatography (hereinafter referred to as "GPC") to prepare a calibration curve using an oxyalkylene polymer having a known hydroxyl group-equivalent molecular weight. The molecular weight distribution is a value calculated from Mw and Mn, and is a ratio of Mw to Mn (Mw/Mn).

The molecular weight per main chain terminal group is calculated by applying the value of the hydroxyl value in the precursor polymer to the formula of "56,100/(hydroxyl value of precursor polymer)", or by GPC measurement. A calibration curve of the obtained Mn and the molecular weight per main chain end group obtained from the hydroxyl value was prepared in advance for each number of active hydrogens of the initiator, and the Mn measurement result to be obtained was calculated using this relationship. May be calculated by the method of converting into the molecular weight per main chain terminal group.

The polystyrene-equivalent number average molecular weight (hereinafter referred to as “PS-Mn”) and the polystyrene-equivalent weight average molecular weight (hereinafter referred to as “PS-Mw”) in the present specification refer to GPC using THF as an eluent. Is a polystyrene-equivalent molecular weight measured by preparing a calibration curve using a polystyrene polymer of known molecular weight. In an oxyalkylene polymer, PS-Mn and PS-Mw tend to be measured larger than the above Mn and Mw. The value calculated by PS-Mw/PS-Mn is almost the same as the above Mw/Mn.

The curable composition of the present invention has two or more main chain terminal groups in one molecule, has more than 0.5 of the following reactive silicon groups on average in one molecule, and has a number average molecular weight of A polymer of 10,000 to 60,000, a tetravalent tin catalyst, an alkyl alcohol having 1 to 6 carbon atoms, an alkoxysilane having an alkoxy group having 1 to 4 carbon atoms, a monovalent carboxylic acid, and It contains at least one compound A selected from the group consisting of diketones represented by formula 2. Further, the content of the tetravalent tin catalyst is less than 1.0 part by mass with respect to 100 parts by mass of the polymer.

<Polymer>
The polymer contained in the curable composition of the present invention has two or more main chain terminal groups in one molecule, and on average has more than 0.5 reactive silicon groups below in one molecule. , Mn is 10,000 to 60,000 (hereinafter, referred to as “polymer X”).

(Reactive silicon group)
The reactive silicon group is represented by the following formula 1. The reactive silicon group has a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and can form a siloxane bond and crosslink. The reaction to form a siloxane bond is promoted by a tetravalent tin catalyst.
—SiX _a R ¹ _3-a Formula 1

In Formula 1, R ¹ represents a monovalent organic group having 1 to 20 carbon atoms. R ¹ contains no hydrolyzable group.
R ¹ is preferably at least one selected from the group consisting of a hydrocarbon group having 1 to 20 carbon atoms and a triorganosiloxy group.

R ¹ is preferably at least one selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group, an α-chloroalkyl group and a triorganosiloxy group. At least one selected from the group consisting of a linear or branched alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, a phenyl group, a benzyl group, an α-chloromethyl group, a trimethylsiloxy group, a triethylsiloxy group and a triphenylsiloxy group. Is more preferable. A methyl group or an ethyl group is preferable because the curability of the polymer having a reactive silicon group and the stability of the curable composition are good. The α-chloromethyl group is preferable from the viewpoint that the curing rate of the cured product is high. A methyl group is particularly preferable because it is easily available.

In the above formula 1, X represents a hydroxyl group or a hydrolyzable group.
Examples of the hydrolyzable group include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a sulfanyl group and an alkenyloxy group.
Alkoxy groups are preferred because they have mild hydrolyzability and are easy to handle. The alkoxy group is preferably a methoxy group, an ethoxy group or an isopropoxy group, more preferably a methoxy group or an ethoxy group. When the alkoxy group is a methoxy group or an ethoxy group, a siloxane bond is quickly formed and a crosslinked structure is easily formed in the cured product, and the cured product tends to have good physical properties.

In Formula 1, a represents an integer of 1 to 3. When a is 1, R ¹ may be the same or different. When a is 2 or more, X may be the same or different.
a is preferably 1 or 2, and a is more preferably 2.

Examples of the reactive silicon group represented by the above formula 1 include trimethoxysilyl group, triethoxysilyl group, triisopropoxysilyl group, tris(2-propenyloxy)silyl group, triacetoxysilyl group, dimethoxymethylsilyl group, Examples thereof include diethoxymethylsilyl group, dimethoxyethylsilyl group, diisopropoxymethylsilyl group, (α-chloromethyl)dimethoxysilyl group, and (α-chloromethyl)diethoxysilyl group. From the viewpoint of high activity and good curability, a trimethoxysilyl group, a triethoxysilyl group, a dimethoxymethylsilyl group and a diethoxymethylsilyl group are preferable, and a dimethoxymethylsilyl group and a trimethoxysilyl group are more preferable.

The polymer X contained in the curable composition of the present invention may be one type or two or more types. In the curable composition of the present invention, as the polymer X, at least an oxyalkylene polymer (hereinafter referred to as "polymer A") or a (meth)acrylic acid ester polymer (hereinafter referred to as "polymer B"). It is preferable to include one of them.

<Polymer A>
The polymer A contained in the curable composition of the present invention may be one type or two or more types.
The main chain of the polymer A is a polymer chain composed of an oxyalkylene polymer formed by polymerizing one or more alkylene oxide monomers. When it is a copolymer chain formed by polymerization of two or more alkylene oxide monomers, those alkylene oxide monomers may form a block polymer or a random polymer. Good.
As a polymer chain composed of an oxyalkylene polymer, a polymer chain composed of an ethylene oxide monomer, a polymer chain composed of a propylene oxide monomer, a polymer chain composed of a butylene oxide monomer, a polymer chain composed of a tetramethylene oxide monomer, Examples thereof include a copolymer chain of ethylene oxide monomer and propylene oxide monomer, and a copolymer chain of propylene oxide monomer and butylene oxide monomer. A polymer chain composed of a propylene oxide monomer is particularly preferable.

The polymer A preferably has 2 to 6 main chain terminal groups in one molecule, more preferably has 2 to 4 main chain groups, more preferably has 2 or 3 groups, and particularly preferably has 3 groups. preferable.
The terminal group in the main chain terminal group of the polymer A is any one of the reactive silicon group represented by the above formula 1, the active hydrogen-containing group and the unsaturated group, and the reactive silicon group represented by the above formula 1 One or more groups selected from the group consisting of a hydroxyl group and an allyl group are preferred. The respective terminal groups may be the same as or different from each other.
The polymer A preferably has an average of more than 0.5 and no more than 2.0 reactive silicon groups per main chain terminal group, and the cured product tends to have a good tensile strength, and therefore, the polymer A has a resistance of 0. Those having 6 to 1.9 are more preferable.
The polymer A preferably has an average of more than 0.5 and not more than 6 reactive silicon groups per molecule, and the tensile strength of the cured product tends to be good, so 1.2 to 3.8. It is more preferable to have one.

Mn per main chain terminal group of the polymer A is 2,500 or more, preferably 2,500 to 20,000, and more preferably 3,000 to 10,000. Within the above range, the cured product tends to have excellent elongation properties and the viscosity tends to be sufficiently low.
The Mn of the polymer A is preferably 5,000 to 60,000, more preferably 5,000 to 50,000, and even more preferably 6,000 to 40,000. Within the above range, the cured product tends to have excellent elongation properties and the viscosity tends to be sufficiently low.
The polymer A has a PS-Mn of preferably from 5,500 to 84,000, more preferably from 6,000 to 70,000, still more preferably from 6,600 to 56,000. Within the above range, the cured product tends to have excellent elongation properties and the viscosity tends to be sufficiently low.
The molecular weight distribution of the polymer A is preferably 1.8 or less. The molecular weight distribution is preferably small, more preferably 1.0 to 1.5, even more preferably 1.02 to 1.4, and particularly preferably 1.04 to 1.2, since good elongation properties are easily obtained.

Polymer A is obtained by introducing the above-mentioned reactive silicon groups into the main chain terminal groups of the below-mentioned precursor polymer on average in one main chain terminal group in excess of 0.5 to 2.0 or less. From the viewpoint of good tensile strength, those obtained by introducing 0.6 to 1.9 pieces are more preferable.
The precursor polymer is an oxyalkylene polymer obtained by ring-opening addition polymerization of an alkylene oxide monomer with active hydrogen of an initiator having an active hydrogen-containing group in the presence of a ring-opening polymerization catalyst. The precursor polymer is preferably a precursor polymer obtained by ring-opening addition polymerization of an alkylene oxide monomer with an initiator having a hydroxyl group and having a hydroxyl group as the main chain terminal group.

The method for producing the polymer A is a method of introducing one or two unsaturated groups to one main chain terminal group of the precursor polymer, and then reacting the unsaturated group with a silylating agent, or A method in which an active hydrogen-containing group at the main chain terminal group of the precursor polymer and an isocyanate silane compound are subjected to a urethane reaction is preferable.
The precursor polymer is an oxyalkylene polymer obtained by ring-opening addition-polymerizing an alkylene oxide monomer with 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 of the initiator, the number of main chain end groups of the precursor polymer, and the number of main chain end groups of the polymer A are the same.
The precursor polymer is preferably a polymer obtained by ring-opening addition polymerization of an alkylene oxide monomer with an initiator having a hydroxyl group, and the terminal group of the main chain terminal group is a hydroxyl group.
The initiator is preferably an initiator having 2 to 6 hydroxyl groups, more preferably an initiator having 2 to 4 hydroxyl groups, more preferably an initiator having 2 hydroxyl groups or an initiator having 3 hydroxyl groups, Those having three are particularly preferable. The initiator may be used alone or in combination of two or more.
As the initiator having two hydroxyl groups, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, low molecular weight The polyoxypropylene glycol can be exemplified.
Examples of the initiator having three hydroxyl groups include glycerin, trimethylolpropane, trimethylolethane, sorbitol, pentaerythritol, and low molecular weight polyoxypropylenetriol.

As the ring-opening polymerization catalyst when the alkylene oxide monomer is subjected to the ring-opening addition polymerization as an initiator, a conventionally known catalyst can be used. For example, an alkali catalyst such as KOH, an organoaluminum compound and porphyrin can be used. Examples of the catalyst include a transition metal compound-porphyrin complex catalyst such as a complex obtained by the reaction, a complex metal cyanide complex catalyst, and a phosphazene compound.
The double metal cyanide complex catalyst is preferable because the molecular weight distribution of the polymer A can be narrowed and a curable composition having a low viscosity can be easily obtained. As the complex metal cyanide complex catalyst, a conventionally known compound can be used, and as the method for producing a polymer using the complex metal cyanide complex, a known method can be adopted. For example, International Publication No. 2003/062301, International Publication No. 2004/067633, JP2004-297776A, JP2005-15786A, International Publication WO2013/065802, JP2015-010162A. The compounds and production methods disclosed in the publication can be used.
The precursor polymer of the polymer A is preferably a precursor polymer in which all the main chain terminal groups are hydroxyl groups.

The method for producing the polymer A is a method in which one or two unsaturated groups are introduced into one main chain terminal group of the precursor polymer, and then the unsaturated group is reacted with a silylating agent, or the precursor is used. A method in which the active hydrogen-containing group at the main chain terminal group of the polymer and the isocyanate silane compound are subjected to a urethane reaction is preferable.
As the silylating agent, a compound having both a group capable of reacting with an unsaturated group to form a bond (for example, a sulfanyl group) and the reactive silicon group, a hydrosilane compound (for example, HSiX _a R _3-a , provided that X , R and a are the same as those in the above formula 1.). Specifically, for example, trimethoxysilane, triethoxysilane, triisopropoxysilane, tris(2-propenyloxy)silane, triacetoxysilane, methyldimethoxysilane, methyldiethoxysilane, methoxyethylsilane, methyldiisopropoxy. Examples thereof include silane, (α-chloromethyl)dimethoxysilane, and (α-chloromethyl)diethoxysilane. From the viewpoint of high activity and good curability, trimethoxysilane, triethoxysilane, methyldimethoxysilane and methyldiethoxysilane are preferable, and methyldimethoxysilane and trimethoxysilane are more preferable.
As the isocyanate silane compound, for example, a conventionally known isocyanate silane compound described in JP 2011-178955 A can be used.
A method of introducing one unsaturated group into one main chain terminal group of the precursor polymer and then reacting the unsaturated group with a silylating agent, or containing active hydrogen in the main chain terminal group of the precursor polymer. As a method of urethanizing a group with an isocyanate silane compound, a conventionally known method can be used. For example, JP-B-45-36319, JP-A-50-156599, JP-A-61-197631, and JP-A-61-197631. The methods proposed in JP-A-3-72527, JP-A-8-231707, JP-A-2011-178955, US Pat. No. 3,632,557 and US Pat. No. 4,960,844 are mentioned.

As a method of introducing two unsaturated groups into one main chain terminal group of the precursor polymer, an alkali metal salt is allowed to act on the precursor polymer, and then an epoxy compound having an unsaturated group is reacted, Then, a method of reacting a halogenated hydrocarbon compound having an unsaturated group is preferable.

As a method for introducing more than one unsaturated group into one main chain terminal group of the precursor polymer, a known method can be used without particular limitation. For example, International Publication No. 2013/180203, International Publication No. Publication No. 2014/192842, JP-A-2015-105293, JP-A-2015-105322, JP-A-2015-105323, JP-A-2015-105324, International Publication No. 2015/080067, International Publication No. 2015/ The methods described in 105122, WO 2015/111577, WO 2016/002907, JP 2016-216633, and JP 2017-39782 can be used.

By the reaction, an unsaturated group derived from the epoxy compound having the unsaturated group is introduced into the main chain terminal group of the precursor polymer, and then an unsaturated group derived from the halogenated hydrocarbon compound is introduced. Is obtained. A part of the end groups in the main chain end group of the intermediate may be an unreacted active hydrogen-containing group.
From the viewpoint of storage stability, the number of active hydrogen-containing groups contained in one molecule of the intermediate is preferably 0.3 or less, more preferably 0.1 or less.

The silylation ratio of the polymer A is preferably more than 50 mol% and 100 mol% or less, more preferably 55 to 98 mol%, and further preferably 60 to 97 mol%.
When the curable composition contains two or more kinds of the polymer A, the average silylation rate in the whole polymer A may be within the above range.

<Polymer B>
The polymer B contained in the curable composition of the present invention may be one type or two or more types.
The main chain of the polymer B is formed by polymerizing a monomer containing a (meth)acrylic acid ester.
The reactive silicon group in the polymer B may be introduced into the main chain terminal group, the side chain, or both the main chain terminal group and the side chain.
The main chain of the polymer B may have a unit based on a monomer having an unsaturated group copolymerizable with the (meth)acrylic acid alkyl ester, in addition to the unit based on the (meth)acrylic acid alkyl ester. Good.
As the monomer constituting the polymer B, for example, conventionally known monomers described in JP-B-3-14068, JP-A-6-211922, and JP-A-11-130931 are used. be able to.
The monomer containing a reactive silicon group and an unsaturated group to be copolymerized with the monomer, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, Vinyltrichlorosilane, tris(2-methoxyethoxy)vinylsilane, (meth)acrylic acid-3-(methyldimethoxylyl)propyl, (meth)acrylic acid-3-(trimethoxysilyl)propyl, (meth)acrylic acid-3 An example is -(triethoxysilyl)propyl. These may be used alone or in combination of two or more.
The (meth)acrylic acid ester monomer is preferably 50% by mass or more, more preferably 70% by mass or more, and even 100% by mass with respect to all the monomers constituting the polymer B.

The polymer B can be polymerized by a conventionally known polymerization method described in JP 2006-257405 A, JP 2006-37076 A, JP 2008-45059 A, or the like. Conventionally known auxiliary materials such as an initiator necessary for the polymerization can be used, and reaction conditions such as reaction temperature and reaction pressure can be appropriately selected.
Examples of the polymerization method include solution polymerization, emulsion polymerization, suspension polymerization or bulk polymerization, and a living radical polymerization using a radical polymerization initiator. As a living radical polymerization method, a method using a cobalt porphyrin complex as shown in Journal of American Chemical Society (J. Am. Chem. Soc.), Vol. 116, p. One using a nitroxide radical as shown in Table 2003-500378, an organic halide or a sulfonyl halide compound as shown in JP-A No. 11-130931 as an initiator, and a transition metal Atom transfer radical polymerization (ATRP method) using a complex as a catalyst can be exemplified. The polymer obtained by living radical polymerization has a narrow molecular weight distribution and tends to have low viscosity.

The main chain terminal group of the polymer B depends on the type of monomer used in the polymerization and auxiliary materials, but for example, a unit based on an unsaturated bond group in the monomer constituting the polymer B, a group based on a polymerization initiator. Alternatively, when a molecular weight modifier is used, a unit based on the molecular weight modifier is included.
The Mn of the polymer B is preferably 5,000 to 60,000, more preferably 5,000 to 50,000, and even more preferably 6,000 to 40,000. When it is at least the lower limit of the above range, the elongation property of the cured product tends to be excellent, and when it is at most the upper limit, the viscosity tends to be low and workability tends to be excellent.
5,500-84,000 are preferable, as for PS-Mn of the polymer B, 6,000-570,000 are more preferable, and 6,600-56,000 are more preferable. When it is at least the lower limit of the above range, the elongation property of the cured product tends to be excellent, and when it is at most the upper limit, the viscosity tends to be low and workability tends to be excellent.
The molecular weight distribution of the polymer B is preferably 5.0 or less, more preferably 3.5 or less.

The average number of reactive silicon groups per molecule of the polymer B is more than 0.5, preferably 1.0 or more. From the viewpoint of strength after curing, 1.2 or more are preferable, and 1.6 or more are more preferable. From the viewpoint of good elongation of the cured product, 4.0 or less is preferable, and 3.0 or less is more preferable.
The average number of reactive silicon groups per molecule of the polymer B is calculated by "concentration of reactive silicon group in the polymer B [mol/g] x PS-Mn of the polymer B". The concentration [mol/g] of the reactive silicon group in the polymer B can be measured by NMR.

<Polymer X>
The polymer X preferably contains either one or both of the polymer A and the polymer B. The total ratio of the polymer A and the polymer B in the polymer X is preferably 80% by mass or more, more preferably 90% by mass or more, and even 100% by mass with respect to the polymer X. When it is at least the above lower limit, the physical properties of the cured product tend to be good.
When the polymer A and the polymer B are included, the mass ratio of the polymer B to the polymer A (polymer B/polymer A) is preferably 5 to 45/55 to 95, and 10 to 40/60 to 90 is more preferable, and 15-35/65-85 is still more preferable. Within the above range, the curability is likely to be excellent.
The polymer X may contain a polymer other than the polymer A and the polymer B. The polymer may have two or more main chain terminal groups in one molecule and average more than 0.5 reactive silicon groups represented by the above formula 1 in one molecule. For example, the main chain skeleton of the polymer is not particularly limited. Examples of the main chain skeleton include saturated hydrocarbon polymers, polyester polymers, vinyl polymers other than polymer B, polysulfide polymers, polyamide polymers, polycarbonate polymers, diallylphthalate polymers. Are listed.

<Compound A>
The curable composition of the present invention comprises a group consisting of an alkyl alcohol having 1 to 6 carbon atoms, an alkoxysilane having an alkoxy group having 1 to 4 carbon atoms, a monovalent carboxylic acid, and a diketone represented by the following formula 2. It contains at least one compound A selected. By containing the compound A, the curable composition of the present invention is suppressed in curability deterioration even after storage at high temperature.

Examples of the alkyl alcohol having 1 to 6 carbon atoms include alcohols represented by the following formula 3.
R ⁵ —OH formula 3
In Formula 3, R ⁵ represents a linear or branched alkyl group having 1 to 6 carbon atoms.
Examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group and an n-hexyl group. Examples of the branched alkyl group include isopropyl group, s-butyl group, t-butyl group, 2-methylbutyl group, 2-ethylbutyl group, 3-methylbutyl group, 3-ethylbutyl group, 2-methylpentyl group, 3-methyl group. Examples thereof include a pentyl group and a 4-methylpentyl group.

Examples of the alcohol represented by the formula 3 include monohydric alcohols having a linear or branched alkyl group having 1 to 6 carbon atoms. Specific examples include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 1-pentanol, 1-hexanol and isobutanol. From the viewpoint of easily maintaining the catalytic activity, a monovalent alcohol having a linear alkyl group having 1 to 4 carbon atoms is preferable, methanol and ethanol are more preferable, and methanol is further preferable.

Examples of the alkoxysilane having an alkoxy group having 1 to 4 carbon atoms include alkoxysilane represented by the following formula 4.

In Formula 4, R ^{6 to} R ⁹ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. However, not all of R ^{6 to} R ⁹ are hydrogen atoms. From the viewpoint of easily improving the curability, it is preferable that R ^{6 to} R ⁹ are the same.
Examples of R ^{6 to} R ⁹ include a methyl group, an ethyl group, an n-propyl group, a butyl group, an isopropyl group, a s-butyl group, and a t-butyl group.

Examples of the alkoxysilane having an alkoxy group having 1 to 4 carbon atoms represented by the formula 4 include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. From the viewpoint of easily maintaining the catalytic activity, tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane are preferable, and tetraethoxysilane is more preferable.

Examples of the monovalent carboxylic acid include monovalent carboxylic acids represented by the following formula 5.

In Formula 5, R ¹⁰ represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 10 carbon atoms. As the hydrocarbon group, a linear or branched alkyl group having 1 to 10 carbon atoms is preferable.
Examples of the linear or branched alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group. Group, n-decyl group, isopropyl group, s-butyl group, t-butyl group, 2-methylbutyl group, 2-ethylbutyl group, 2-propylbutyl group, 3-methylbutyl group, 3-ethylbutyl group, 3-propylbutyl group Group, 2-methylpentyl group, 2-ethylpentyl group, 2-propylpentyl group, 3-methylpentyl group, 3-ethylpentyl group, 3-propylpentyl group, 4-methylpentyl group, 4-ethylpentyl group, 4-propylpentyl group, 2-methylhexyl group, 2-ethylhexyl group, 2-propylhexyl group, 3-methylhexyl group, 3-ethylhexyl group, 3-propylhexyl group, 4-methylhexyl group, 4-ethylhexyl group , 4-propylhexyl group, 5-methylhexyl group, 5-ethylhexyl group, 5-propylhexyl group and the like.

Examples of the monovalent carboxylic acid represented by Formula 5 include formic acid, acetic acid, propionic acid, butanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid and the like. From the viewpoint of maintaining the catalytic activity, propionic acid or acetic acid is preferable, and acetic acid is particularly preferable.

The compound represented by the following formula 2 is a diketone.
^{_{R 2 -C (O) - (}} CH 2) n -C (O) -R 3 Formula 2

In Formula 2, n represents an integer of 1 to 6. 1-4 are preferable and, as for n, 1 or 2 is more preferable.

In Formula 2, R ² and R ³ each independently represent an alkyl group having 1 to 20 carbon atoms.
As a C1-C20 alkyl group, a C1-C20 linear or branched alkyl group can be illustrated, A C1-C18 linear alkyl group is preferable and a C1-C10 linear chain. Is more preferable, and a linear alkyl group having 1 to 6 carbon atoms is further preferable. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, i-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group. Group, dodecyl group, octadecyl group, etc. can be exemplified, and a linear alkyl group having 1 to 6 carbon atoms is preferable from the viewpoint of easy coordination with tetravalent tin, and a methyl group, an ethyl group, an n-propyl group or an isopropyl group. Is more preferable.

The compound represented by Formula 2 is preferably a compound capable of forming an enol and having active hydrogen by hydrogenation of an oxygen atom of a carbonyl group.
Examples of the compound represented by the formula 2 include hexane 2,5-dione, heptane 3,5-dione, and acetylacetone. From the viewpoint of easily maintaining the catalytic activity of tetravalent tin, hexane 2,5-dione and acetylacetone are preferable, and acetylacetone is more preferable.

<Tetravalent tin catalyst>
The curable composition of the present invention contains a tetravalent tin catalyst.
The tetravalent tin catalyst is preferably a compound obtained by mixing a compound containing a tin atom and the compound A. That is, a tetravalent tin catalyst having a tetravalent tin atom and a residue of the compound A as constituent components is preferable. The residue of the compound A means a group excluding a hydrogen atom of a hydroxyl group, a group excluding a hydrogen atom of a carboxy group, and an oxygen atom of one carbonyl group when the compound A has a plurality of carbonyl groups in the compound A. Examples thereof include a group obtained by removing a hydrogen atom in an enol generated by hydrogenating an atom, a group obtained by removing an alkyl group from an alkoxy group, and the like.
The tetravalent tin catalyst is preferably a tetravalent tin catalyst represented by the following formulas 6-9.

The compound represented by the following formula 6 is a tetravalent tin catalyst containing a residue obtained by removing the hydrogen atom of the hydroxyl group from the compound represented by the above formula 3 as a constituent component.

In Formula 6, R ¹¹ and R ¹² each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms.
Examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group and an n-octyl group.
Examples of the branched alkyl group include isopropyl group, s-butyl group, t-butyl group, 2-methylbutyl group, 2-ethylbutyl group, 2-propylbutyl group, 3-methylbutyl group, 3-ethylbutyl group, 3-propylbutyl group. Group, 2-methylpentyl group, 2-ethylpentyl group, 2-propylpentyl group, 3-methylpentyl group, 3-ethylpentyl group, 3-propylpentyl group, 4-methylpentyl group, 4-ethylpentyl group, 4-propylpentyl group, 2-methylhexyl group, 2-ethylhexyl group, 2-propylhexyl group, 3-methylhexyl group, 3-ethylhexyl group, 3-propylhexyl group, 4-methylhexyl group, 4-ethylhexyl group , 4-propylhexyl group, 5-methylhexyl group, 5-ethylhexyl group, 5-propylhexyl group and the like.
From the viewpoint of catalytic activity, R ¹¹ and R ¹² are preferably each independently a butyl group or an octyl group. More preferably, R ¹¹ and R ¹² are the same.

In Formula 6, R ¹³ and R ¹⁴ are independently the same as R ^{5 in} Formula 3. R ¹³ and R ¹⁴ are preferably the same.

Examples of the tetravalent tin catalyst represented by the formula 6 include dibutyltin dimethoxide, dioctyl tin dimethoxide, dibutyl tin dietoxide, dioctyl tin dietoxide, dibutyl tin dipropoxide, dioctyl tin dipropoxide, dibutyl tin dibutoxide, dioctyl tin dibutoxide. , Dibutyltin dipentyl oxide, dioctyl tin dipentyl oxide, dibutyl tin dihexyl oxide and dioctyl tin dihexyl oxide.
From the viewpoint of catalytic activity, the tetravalent tin catalyst represented by the above formula 6 is preferably dibutyltin dimethoxide, dioctyltin dimethoxide, dibutyltin diethyloxide, dioctyltin diethyloxide, and particularly preferably dibutyltin dimethoxide or dioctyltin dimethoxide.

The compound represented by the following formula 7 is a tetravalent tin catalyst having a residue obtained by removing any one group of R ^{6 to} R ⁹ from the compound represented by the above formula 4 as a constituent component.

In Formula ^7, R ^{11, R 12} are the same as ^{R 11, R 12} of formula 6.
In Formula 7, R ^{15 to} R ²⁰ are independently the same as R ^{6 to} R ^{9 in} Formula 4, respectively. R ^{15 to} R ²⁰ are preferably the same.

Examples of the tetravalent tin catalyst represented by the formula 7 include a reaction product of a dibutyltin salt or a dioctyltin salt and an alkoxysilane having an alkoxy group having 1 to 4 carbon atoms represented by the formula 4. .. Examples of the dibutyltin salt or dioctyltin salt include dibutyltin dilaurate, dibutyltin dioleyl malate, dibutyltin dibutylmalate, dibutyltin diacetate, dibutyltin di-t-decanoate, dibutyltin distearate, dibutyltin diphthalate, dioctyltin dilaurate. , Dioctyl tin dioleyl malate, dioctyl tin dibutyl maleate, dioctyl tin diacetate, dioctyl tin di-t-decanoate, dioctyl tin distearate, dioctyl tin diphthalate and the like, and dibutyl tin dilaurate and dibutyl tin dimalate are preferable. As the alkoxysilane having an alkoxy group having 1 to 4 carbon atoms represented by the formula 4, tetramethoxysilane, tetraethoxysilane and tetrapropoxysilane are preferable, and tetraethoxysilane is particularly preferable.
Examples of the tetravalent tin catalyst represented by Formula 7 include a reaction product of dibutyltin salt and tetramethoxysilane, a reaction product of dibutyltin salt and tetraethoxysilane, a reaction product of dibutyltin salt and tetrapropoxysilane, and dioctyltin. A salt and a reaction product of tetramethoxysilane, a reaction product of a dioctyltin salt and a tetraethoxysilane, a reaction product of a dioctyltin salt and a tetrapropoxysilane are preferable, a reaction product of a dibutyltin salt and a tetramethoxysilane, a dibutyltin salt and a tetraethoxysilane. A silane reaction product, a dioctyltin salt-tetramethoxysilane reaction product, a dioctyltin salt-tetraethoxysilane reaction product is more preferred, and a dibutyltin salt-tetraethoxysilane reaction product, a dioctyltin salt-tetraethoxysilane reaction product. The thing is more preferable.

The compound represented by the following formula 8 is a tetravalent tin catalyst containing a residue of the compound represented by the above formula 5 excluding the hydrogen atom of the carboxy group as a constituent component.

In the formula ^8, R ^{11, R 12} are the same as ^{R 11, R 12} of formula 6.
In Formula 8, R ²¹ and R ²² are independently the same as R ^{10 in} Formula 5. R ²¹ and R ²² are preferably the same.

Examples of the tetravalent tin catalyst represented by Formula 8 include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctanoate, dioctyltin dioctanoate, dibutyltin bis(2-ethylhexanoate), dioctyltin bis(2-ethyl). Hexanoate), dibutyltin diacetate, dioctyltin diacetate and the like.
From the viewpoint of catalytic activity, the tetravalent tin catalyst represented by Formula 8 is preferably dibutyltin diacetate, dioctyltin diacetate, dibutyltin dilaurate or dioctyltin dilaurate, and particularly preferably dibutyltin diacetate or dibutyltin dilaurate. preferable.

The compound represented by the following formula 9 is a constituent component of the enol formed by hydrogenating the oxygen atom of one carbonyl group of the compound represented by the above formula 2 except for the hydrogen atom. It is a tetravalent tin catalyst.

In Formula 9, 1 and m each independently represent an integer of 0 to 5. 0 and 2 are preferable and, as for 1 and m, 0 and 1 are more preferable. It is preferable that m and l are the same.
In Formula ^9, R ^{11, R 12} are the same as ^{R 11, R 12} of formula 6.
In the formula 9, R ^{23 to} R ²⁶ are independently the same as R ² and R ^{3 in the} formula 2. R ^{23 to} R ²⁶ are preferably the same.

Examples of the tetravalent tin catalyst represented by the above formula 9 include dibutyltin bis(acetylacetonate), dioctyltin bis(acetylacetonate), dibutyltin bis(ethylacetonate), dioctyltin bis(ethylacetonate). , Dibutyltin bis(methylpropionate), dioctyltin bis(methylpropionate), and the like.
From the viewpoint of catalytic activity, the tetravalent tin catalyst represented by the above formula 9 includes dibutyltin bis(ethylacetonate), dioctyltin bis(ethylacetonate), dibutyltin bis(acetylacetonate), dioctyltin bis. (Acetylacetonate) is preferable, and dibutyltin bis(acetylacetonate) and dioctyltin bis(acetylacetonate) are particularly preferable.

The content of the tetravalent tin catalyst with respect to 100 parts by mass of the polymer is less than 1.0 part by mass, preferably 0.8 parts by mass or less, and more preferably 0.7 parts by mass or less. When the content of the tetravalent tin catalyst with respect to 100 parts by mass of the polymer is less than the upper limit of 1.0 parts by mass, the cured product has good restorability and excellent adherence to the adherend.

The content of the compound A with respect to 100 mol of the tetravalent tin catalyst is preferably 100 to 2,500 mol, more preferably 120 to 2,400 mol, still more preferably 150 to 2,200 mol. When the content of the compound A relative to 100 mol of the tetravalent tin catalyst is at least the lower limit value of the above range, the curability does not decrease even after storage at high temperature, and when it is at most the upper limit value, the recoverability is excellent.

<Combination of Compound A and tetravalent tin catalyst>
As the combination of the compound A and the tetravalent tin catalyst contained in the curable composition of the present invention, the compound A to be mixed with the compound containing a tin atom when the tetravalent tin catalyst is prepared, and the curable composition The compounds A contained in 1 may be the same or different and are preferably the same.
Specific examples of the combination of the compound A and the tetravalent tin catalyst contained in the curable composition of the present invention include the compound A represented by the formula 3 and the tetravalent tin catalyst represented by the formula 6. A combination of the compound A represented by the formula 4 and the tetravalent tin catalyst represented by the formula 7, the compound A represented by the formula 5 and the compound represented by the formula 8 A combination with a valent tin catalyst and a combination of the compound A represented by the formula 2 and the tetravalent tin catalyst represented by the formula 9 are preferable.

In the case of the combination of the compound A represented by the formula 3 and the tetravalent tin catalyst represented by the formula 6, R ^{5 of the} formula 3 and R ^{11 to} R ^{14 of the} formula 6 are the same. It is preferable.
In the case of the combination of the compound A represented by the formula 4 and the tetravalent tin catalyst represented by the formula 7, R ^{6 to} R ^{9 of the} formula 4 and R ^{15 to} R ^{20 of the} formula 7 are: It is preferable that they are the same.
In the case of the combination of the compound A represented by the formula 5 and the tetravalent tin catalyst represented by the formula 8, R ^{10 of the} formula 5 and R ²¹ and R ^{22 of the} formula 8 are the same. It is preferable to have.
In the case of the combination of the compound A represented by the formula 2 and the tetravalent tin catalyst represented by the formula 9, R ² and R ^{3 of the} formula 2 and R ²³ _and R ^{24 of the} formula 9 are the same. And it is preferable that R ² and R ³ of the formula 2 are the same as R ^{25 and} R ^{26 of the} formula 9.
When the compound A and the tetravalent tin catalyst are in the above combination, the effect of suppressing the decrease in curability after the curable composition is stored at high temperature is further enhanced.

<Other ingredients>
The curable composition may include other components other than the polymer X, the compound A, and the tetravalent tin catalyst. Other components include oxyalkylene polymers other than the polymer X and (meth)acrylic acid ester polymers, curable compounds, fillers, plasticizers, thixotropic agents, stabilizers, adhesion imparting agents, and physical properties. Examples include regulators, tackifying resins, reinforcing materials such as fillers, surface modifiers (surfactants), flame retardants, foaming agents, solvents, and silicates.
As the oxyalkylene polymer and the (meth)acrylic acid ester polymer other than the polymer X, there are two main chain terminal groups in one molecule, and one main chain terminal has an average of the above formula 1 An oxyalkylene polymer having more than 0 and no more than 0.5 reactive silicon groups represented, an oxyalkylene polymer having no reactive silicon groups, and a (meth)acrylic acid ester having no reactive silicon groups. Examples thereof include polymers.
Curable compounds, fillers, plasticizers, thixotropic agents, stabilizers, adhesion imparting agents, physical property modifiers, tackifying resins, reinforcing materials such as fillers, surface modifiers (surfactants), flame retardants , A foaming agent, a solvent, and a silicate are WO 2013/180203, WO 2014/192842, WO 2016/002907, JP-A-2014-88481, and JP-A-2015-10162, respectively. Conventionally known ones described in JP-A-2015-105293, JP-A-2017-039728, JP-A-2017-214541 and the like can be used in combination without limitation.

<Curable composition>
The content of the polymer X in the curable composition of the present invention is 1 to 80% by mass, preferably 5 to 60% by mass, more preferably 10 to 50% by mass.

The curable composition is obtained by synthesizing a polymer to be mixed with the curable composition and mixing the obtained polymer with a compounding component other than the polymer.
The total content of the polymer A and the polymer B in the curable composition is preferably 1 to 80% by mass, more preferably 5 to 60% by mass, and even more preferably 10 to 50% by mass. When it is at least the lower limit of the above range, the mechanical strength tends to be excellent, and when it is at most the upper limit, the viscosity tends to be low and the elongation properties and fatigue resistance tend to be excellent.
The content ratio of the polymer A in the curable composition when the polymer A is contained is preferably 0.5 to 79.5% by mass, more preferably 3 to 58% by mass, and further preferably 7 to 47% by mass. .. When it is at least the lower limit value of the above range, the mechanical strength tends to be excellent, and when it is at most the upper limit value, the viscosity tends to be low and workability tends to be excellent.
The content ratio of the polymer B in the curable composition when the polymer B is contained is preferably 0.5 to 79.5% by mass, more preferably 2 to 57% by mass, and further preferably 3 to 43% by mass. .. When it is at least the lower limit of the above range, the mechanical strength tends to be excellent, and when it is at most the upper limit, the viscosity tends to be low and the workability tends to be excellent.
The mass ratio of the content of the polymer A to the content of the polymer B in the curable composition containing the polymer A and the polymer B (content of the polymer A/content of the polymer B) is (100/1 to 60) is preferable, (100/10 to 50) is more preferable, and (100/20 to 40) is further preferable. Within the above range, the mechanical strength is likely to be excellent, and the elongation properties and the restorability are likely to be excellent.

The curable composition is preferably a one-component type in which all the compounding ingredients are mixed in advance, sealed and stored, and then cured by the moisture in the air after the construction.
The one-component curable composition preferably contains no water. It is preferable to dehydrate and dry the compounding components containing water in advance, or to dehydrate by reducing the pressure during compounding and kneading.

The curable composition can be used as a sealing material (for example, an elastic sealing material for construction, a sealing material for double glazing, a rustproof/waterproof sealing material for the glass edge, a solar cell backside sealing material, and a building sealing material. Materials, sealing materials for ships, sealing materials for automobiles, sealing materials for roads), electrical insulating materials (insulating coating materials for electric wires and cables), and adhesives are suitable.
In particular, it is suitable for applications requiring stretch properties and stretch fatigue resistance of the cured product, and examples thereof include sealing materials that are applied outdoors.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following description.

[Molecular weight and molecular weight distribution]
It carried out by the above-mentioned method using HLC-8220GPC (product name of Tosoh Corporation).

[Silylation rate, number of silyl groups]
In the method of introducing an unsaturated group into the main chain terminal group using allyl chloride, and introducing a reactive silicon group by reacting a silylating agent with the unsaturated group, an unsaturated group introduced into the main chain terminal group The charged equivalent (molar ratio) of the reactive silicon group of the silylating agent was defined as the silylation rate.
In the reaction between the unsaturated group introduced by using allyl chloride and the silylating agent, the unsaturated group which does not react with the silylating agent due to a side reaction is about 10 mol %. Therefore, when less than 90 mol% of the unsaturated groups are reacted with the silylating agent, the charged equivalent becomes the silylation rate.
In the method of introducing a reactive silicon group by urethane-forming the hydroxyl group of the main chain terminal group of the precursor polymer and the isocyanate silane compound, the charged equivalent of the reactive silicon group of the silylating agent to the hydroxyl group of the precursor polymer (mol The ratio) was defined as the silylation rate.

[Tack free time]
The curable composition prepared as described below was filled in a sealing cartridge (manufactured by Showa Marutsu Co., Ltd.), sealed, and then allowed to stand in a constant temperature bath at 70° C. for 1 week. Then, the sealing cartridge was allowed to cool in a constant temperature room at 23° C., and the time required until the sample did not adhere to the fingertip (tack free time) was measured according to JIS A 1439 (2016). The tack free time is an index showing the curability of the composition, and the smaller the value, the faster the curing speed and the better the curability.

[Elasticity recovery rate]
As the adherend, a surface anodized aluminum plate coated with a primer MP-2000 (product name of Cemedine Co., Ltd.) on the surface is used for the test method of the building sealing material of JIS A 1439 5.2 (2016). In conformity with the above, an aluminum adherend was produced and the elastic recovery rate was evaluated.
Specifically, the curable composition is poured between the two aluminum plates, cured at a temperature of 23° C. and a humidity of 50% for 7 days, and further cured at a temperature of 50° C. and a humidity of 65% for 7 days to deposit the aluminum on Got the body The distance between the two aluminum plates of the obtained aluminum adherend was defined as L0. Using a predetermined jig, the distance between the two aluminum plates was extended by 100% with respect to L0 in an environment of a temperature of 23° C. and a humidity of 50%. The distance between the two aluminum plates at this time was set to L1. After holding for 24 hours with the distance between the two aluminum plates kept at L1, the jig was removed and left still for 1 hour, and then the distance between the two aluminum plates was measured as L2. From the values of L0, L1 and L2, the elastic recovery rate (unit: %) was calculated by the following formula 10. The higher the elastic recovery rate, the better the recovery. When the elastic recovery rate is 70% or more, the recoverability is good.
Elastic recovery rate=(L1-L2/L1-L0)×100 Equation 10

(Synthesis Example 1: Polymer A1)
Using glycerin as an initiator and a zinc hexacyanocobaltate complex whose ligand is t-butyl alcohol (hereinafter referred to as "TBA-DMC catalyst") as a catalyst, propylene oxide is polymerized to give an oxypropylene polymer (precursor). Polymer a1) was obtained. The hydroxyl group-converted molecular weight of the precursor polymer a1 was 24,000. Next, 1.05 molar equivalent of a methyl alcohol solution of sodium methoxide with respect to the hydroxyl group of the precursor polymer a1 was added to alcoholate the precursor polymer a1. Next, methanol was distilled off by heating under reduced pressure, and an excess amount of allyl chloride was added to the amount of hydroxyl groups in the precursor polymer a1 to convert the main chain terminal groups into allyl groups. Next, in the presence of chloroplatinic acid hexahydrate, 0.75 molar equivalent of methyldimethoxysilane was added to the converted allyl group of the precursor polymer a1, and reacted at 70° C. for 5 hours, An oxypropylene polymer (polymer A1) in which a methyldimethoxysilyl group was introduced into the main chain terminal group was obtained.
The obtained polymer A1 had Mn of 24,000, Mn per main chain end group of 8,000, Mw/Mn of 1.1, PS-Mn of 32,000, and reactive silicon per main chain end group. The average number of groups was 0.75 (shown in Table 1, the same applies hereinafter).

(Synthesis Example 2: Polymer A2)
Using propylene glycol as an initiator, propylene oxide was polymerized in the presence of a TBA-DMC catalyst to obtain a precursor polymer a2 having a hydroxyl group-converted molecular weight of 12,000. Then, 0.97 molar equivalent of γ-isocyanatopropyltrimethoxysilane with respect to the hydroxyl group of the precursor polymer a2 was reacted using U860 (dioctyltin bis(isooctylthioglycolate), Nitto Kasei Co., Ltd. product name), An oxypropylene polymer (polymer A2) in which a trimethoxysilyl group was introduced into the main chain terminal group was obtained.

(Synthesis Example 3: Polymer A3)
Using propylene glycol as an initiator, propylene oxide was polymerized in the presence of a TBA-DMC catalyst to obtain a precursor polymer a3 having a hydroxyl group-converted molecular weight of 18,000. Next, except that 0.73 molar equivalent of dimethoxymethylsilane is added as a silylating agent to the allyl group of the precursor polymer a3 whose terminal group is converted to an allyl group, obtained in the same manner as in Synthesis Example 1. Then, in the same manner as in Synthesis Example 1, an oxypropylene polymer (polymer A3) in which a dimethoxymethylsilyl group as a reactive silicon group was introduced at the end of the main chain was obtained.

(Synthesis Example 4: Polymer A4)
Propylene glycol was used as an initiator and propylene oxide was polymerized in the presence of a zinc hexacyanocobaltate complex having a glyme ligand to obtain a precursor polymer a4 having a hydroxyl group-equivalent molecular weight of 20,000. Then, 1.05 molar equivalent of a methanol solution of sodium methoxide with respect to the hydroxyl group of the precursor polymer a4 was added to alcoholate the precursor polymer a4. Next, methanol was distilled off by heating under reduced pressure, and an excess amount of allyl chloride was added to the amount of the hydroxyl group of the precursor polymer a4 to convert the terminal group at the main chain terminal into an allyl group. Next, in the presence of chloroplatinic acid hexahydrate, 0.75 molar equivalent of dimethoxymethylsilane was added as a silylating agent to the converted allyl group of the precursor polymer a4, and the mixture was heated at 70° C. for 5 hours. The reaction was carried out to obtain an oxypropylene polymer (polymer A4) in which a dimethoxymethylsilyl group as a reactive silicon group was introduced at the end of the main chain.

(Synthesis Example 5: Polymer A5)
An oxypropylene polymer (precursor a5) was prepared by polymerizing propylene oxide using a polyoxypropylene glycol having an Mn of about 2,000 and two terminal hydroxyl groups as an initiator and a TBA-DMC catalyst as a catalyst. ) Got. The precursor polymer a5 had hydroxyl groups at both ends and had a hydroxyl group-converted molecular weight of 15,000.
A methanol solution of sodium methoxide in an amount of 1.15 molar equivalent to the hydroxyl group of the precursor polymer a5 was added. Methanol was distilled off under reduced pressure by deaeration, 1.05 molar equivalent of allyl glycidyl ether was added to the hydroxyl group of the precursor polymer a5, and the mixture was reacted at 130° C. for 2 hours. Then, 0.28 molar equivalent of sodium methoxide in methanol was added to remove methanol, 2.10 molar equivalent of allyl chloride was further added, and the reaction was carried out at 130° C. for 2 hours. To give polyoxypropylene polymer (polymer Q1) having an allyl group introduced at the main chain terminal, by removing unreacted allyl chloride from the system under reduced pressure. The average number of allyl groups introduced into one main chain terminal of the polymer Q1 was 2.0. Then, 0.80 molar equivalent of dimethoxymethylsilane was added as a silylating agent to the allyl group of the polymer Q1 in the presence of a platinum divinyldisiloxane complex, and the mixture was reacted at 70° C. for 5 hours and then unreacted. Was removed under reduced pressure to obtain a polymer in which a dimethoxymethylsilyl group as a reactive silicon group was introduced at the end of the main chain (polymer A5).
The obtained polymer A5 had Mn of 23,000, Mw/Mn of 1.07, PS-Mn of 31,000, and a silylation ratio of 80 mol %. Further, the number of main chain ends of the polymer A5 is 2.0, the average number of allyl groups per molecule in the polymer Q1 is 4.0, and the number of reactive silicon groups per molecule calculated based on the silylation rate The average number was 3.2, and the average number of reactive silicon groups per main chain end was 1.6.
(Synthesis Example 6: Polymer B1)
The following polymer B1 was synthesized by a method of reacting a compound having two alkenyl groups at the final stage of the polymerization reaction using the living radical polymerization method.
8.39 g of cuprous bromide and 112 mL of acetonitrile were added to a 2 L flask, and the mixture was heated with stirring at 70° C. for 20 minutes under a nitrogen stream. To this was added 17.6 g of diethyl 2,5-dibromoadipate, 130 mL of ethyl acrylate, 720 mL of butyl acrylate, and 251 g of stearyl acrylate, and the mixture was further heated and stirred at 70° C. for 40 minutes. To this, 0.41 mL of pentamethyldiethylenetriamine (hereinafter referred to as "triamine") was added to start the reaction. Then, heating and stirring were continued at 70° C., and 2.05 mL of triamine was further added. After 330 minutes from the start of the reaction, 244 mL of 1,7-octadiene and 4.1 mL of triamine were added, followed by continued heating and stirring at 70° C., and heating was stopped 570 minutes after the start of the reaction.
The obtained reaction solution was diluted with toluene and filtered, and the filtrate was heat-treated under reduced pressure to obtain an acrylate polymer having an alkenyl group at the end (polymer Q2).
The Mn of the polymer Q2 was 22,800, the molecular weight distribution was 1.40, and the average number of alkenyl groups per molecule of the polymer Q2 determined by 1H-NMR analysis was 2.8.
Under a nitrogen atmosphere, the total amount of the obtained polymer Q2, 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 the mixture was heated at 100° C. The mixture was heated and stirred for 10 hours. The reaction solution was heated under reduced pressure to remove DMAc, toluene was added, and the mixture was filtered. The residue obtained by heating the filtrate under reduced pressure to remove volatile matter was added to a 2 L flask, and 100 g of an adsorbent (a mixture of Kyoward 500SN and Kyoward 700SN (both are Kyowa Chemical product names in a ratio of 1:1)). Was added, and the mixture was heated and stirred at 130° C. for 9 hours under a nitrogen stream. The mixture was diluted with toluene, filtered to remove the adsorbent, and toluene in the filtrate was distilled off under reduced pressure to obtain a polymer (polymer Q3).
In a 1 L pressure resistant reactor, 700 g of polymer Q3, 22.2 mL of dimethoxymethylhydrosilane, 7.71 mL of methyl orthoformate, and a platinum catalyst (0,1,3,3-tetramethyl-1,3 of 0-valent platinum) were used. -Divinyldisiloxane complex) was added. However, the amount of the platinum catalyst used was 9×10 ⁻³ molar equivalents based on the alkenyl group of the polymer Q3. The mixture in the reaction vessel was heated and stirred at 100° C. for 195 minutes. The volatile matter of the mixture was distilled off under reduced pressure to obtain a polymer having a dimethoxymethylsilyl group at the end of the main chain (polymer B1).
The average number of reactive silicon groups per molecule was 2.0 as determined by 1H-NMR analysis.

(Synthesis Example 7: Polymer B2)
50 g of isobutanol was added to a pressure resistant reactor equipped with a stirrer, and the temperature was raised to about 80°C. While maintaining the temperature in the reaction vessel at about 80° C. under stirring in a nitrogen atmosphere, 1.65 g of methyl methacrylate, 373.1 g of -n-butyl acrylate, 110.0 g of stearyl acrylate, and 3-methacryloxy. 6. 5 g of propylmethyldimethoxysilane (KBM-502, product name of Shin-Etsu Silicone Co., Ltd.) and 7,2'-azobis-2,4-dimethylvaleronitrile (V-65, product name of Wako Pure Chemical Industries, Ltd.) 3 g of the mixed solution was dropped into isobutanol over 2 hours for polymerization to obtain a (meth)acrylic acid ester polymer (polymer B2) having a dimethoxymethylsilyl group in its side chain. The average number of reactive silicon groups per molecule was 2.0 as determined by 1H-NMR analysis.

[Preparation of curable composition]
The compounding agents, additives, curing catalysts and compound A shown in Tables 2 to 4 are as follows.
White luster CCR: colloidal calcium carbonate, white luster CCR, product name of Shiroishi Industry Co., Ltd.
Whiten SB: Heavy calcium carbonate, a product name of Shiroishi Industry Co., Ltd.
DINP: Vinylizer 90, diisononyl phthalate, Kao company product.
R-820: Titanium oxide, a product name of Ishihara Sangyo Co., Ltd.
Glycerin monostearate: Reagent, manufactured by Tokyo Chemical Industry Co., Ltd.
TINUVIN 770: Hindered amine light stabilizer, product name of BASF.
Tinuvin 327: Benzotriazole-based UV absorber, product name of BASF Corporation.
KBM-202: diphenyldimethoxysilane, a product name of Shin-Etsu Chemical Co., Ltd.
KBM-1003: vinyltrimethoxysilane, product name of Shin-Etsu Chemical Co., Ltd.
KBM-603: 3-(2-aminoethylamino)propyltrimethoxysilane, a product name of Shin-Etsu Chemical Co., Ltd.
U-200: dibutyltin diacetate, curing catalyst, product name of Nitto Kasei Co., Ltd.
U-220H: dibutyltin bis(acetylacetonate), product name of Nitto Kasei Co., Ltd.
U-303: Reaction product of dibutyltin salt and tetraethoxysilane, product name of Nitto Kasei Co., Ltd.
SCAT27: dibutyltin dimethoxide, product name of Nitto Kasei Co., Ltd.
S-1: Reaction product of dioctyl tin salt and tetraethoxysilane, product name of Nitto Kasei Co., Ltd.
Methanol: Reagent, manufactured by Tokyo Chemical Industry Co., Ltd.
Tetraethoxysilane: Reagent, manufactured by Tokyo Chemical Industry Co., Ltd.
Acetylacetone: Reagent, manufactured by Tokyo Chemical Industry Co., Ltd.

(Examples 1 to 41)
Examples 1-6, 10-12, 15, 17, 17-19, 21-23, 26, 28-30, 32-34, 37-39 are examples, and Examples 7-9, 13, 14, 16, 20. , 24, 25, 27, 31, 35, 36, 40, 41 are comparative examples.
The compounds shown in each of Tables 3 and 4 were blended in a universal mixing stirrer (manufactured by Shinagawa Kogyo Co., Ltd.) in the blending amounts shown in Tables 3 and 4, and further, the blending 1 shown in Table 2 was added and mixed and stirred. A curable composition was prepared. The results of the above evaluations performed using the obtained curable composition are shown in Tables 3 and 4.

As shown in Tables 3 and 4, Examples 1 to 6, 10 to 12, 15, 17 to 19, 21 to 23, 26, 28 to 30, 32 to 34, 37 in which the compound A was used in combination with a tetravalent tin catalyst. In Nos. 39 to 39, tack free time was short, curability was good, elastic recovery rate was high, and sufficient recovery was obtained. Examples 7, 13, 16, 20, 24, 27, 31, 35, and 40 not using the compound A had a high elastic recovery rate, but a long tack free time and poor curability. In Examples 8, 9, 14, 15, 25, 36, and 41 in which the amount of the tetravalent tin catalyst was increased, the tack free time was short and the curability was good, but the elastic recovery rate was low and sufficient recovery was obtained. I couldn't do it.

Claims (6)

Having two or more main chain terminal groups in one molecule and having an average of more than 0.5 reactive silicon groups represented by the following formula 1 in one molecule and having a number average molecular weight of 10,000 to A polymer of 60,000, a tetravalent tin catalyst, an alkyl alcohol having 1 to 6 carbon atoms, an alkoxysilane having an alkoxy group having 1 to 4 carbon atoms, a monovalent carboxylic acid, and the following formula 2 And at least one compound A selected from the group consisting of diketones, and the content of the tetravalent tin catalyst is less than 1.0 part by mass relative to 100 parts by mass of the polymer. Stuff.
—SiX _a R ¹ _3-a Formula 1
[In the formula, R ¹ represents a monovalent organic group having 1 to 20 carbon atoms and represents an organic group other than a hydrolyzable group, and X represents a hydroxyl group or a hydrolyzable group. a represents an integer of 1 to 3, and when a is 1, R ¹ may be the same or different, and when a is 2 or 3, X may be the same or different. ]
^{_{R 2 -C (O) - (}} CH 2) n -C (O) -R 3 Formula 2
[In the formula, n represents an integer of 1 to 6, and R ² and R ³ each independently represent an alkyl group having 1 to 20 carbon atoms. ] The curable composition according to claim 1, wherein the polymer contains at least one of an oxyalkylene polymer and a (meth)acrylic acid ester polymer. The curable composition according to claim 1 or 2, wherein the content ratio of the polymer in the curable composition is 1 to 80% by mass. The curable composition according to claim 1, wherein the tetravalent tin catalyst contains a tetravalent tin catalyst having a tetravalent tin atom and a residue of the compound A as constituent components. .. The curable composition according to any one of claims 1 to 4, wherein the content of the compound A is 100 to 2,500 mol with respect to 100 mol of the tetravalent tin catalyst. The curable composition according to any one of claims 1 to 5, wherein the compound A is at least one compound selected from the group consisting of methanol, tetraethoxysilane, acetic acid and acetylacetone.