JP7619831B2 - Curable resin composition and cured product thereof - Google Patents

Description

The present invention relates to a curable resin composition containing a polymer having a reactive silyl group, and a cured product thereof.

Organic polymers having silicon-containing groups (hereinafter referred to as "reactive silyl groups") that have hydroxyl groups or hydrolyzable groups on silicon atoms and can form siloxane bonds are known as moisture-reactive polymers, and are included in many industrial products such as adhesives, sealants, coating materials, paints, and pressure sensitive adhesives, and are used in a wide range of fields. Among such reactive silyl group-containing polymers, those whose main chain skeleton is a polyoxyalkylene polymer are widely used.

As a method for improving the mechanical properties exhibited after curing such an organic polymer having a reactive silyl group, a technique of blending a polysilsesquioxane-based polymer with the organic polymer is known. A polysilsesquioxane-based polymer is a siloxane-based polymer formed by hydrolysis and dehydration condensation reaction of an organotrialkoxysilane, and is represented by the composition formula: ( _RSiO1.5 ) _n . In the formula, R represents a monovalent organic group such as a methyl group.

For example, Patent Document 1 discloses a crosslinked composition containing a polymer having a reactive silyl group and a silicone resin containing a silsesquioxane unit. Patent Document 2 discloses a composition containing a silsesquioxane containing a phenyl group and an alkoxy group, a silylated polymer containing an alkoxysilane group, and a carbonate filler.

Special Publication No. 2014-521819 Special Publication No. 2020-521034

The present inventors have found that in a system in which a polysilsesquioxane polymer is blended with an organic polymer having a specific reactive silyl group, i.e., a reactive silyl group with two hydroxyl groups or hydrolyzable groups bonded thereto, and a curing catalyst is further blended to improve curing properties, the strength after curing may be significantly reduced.

In view of the above-mentioned current situation, the present invention aims to provide a curable resin composition that contains an organic polymer having a reactive silyl group and a polysilsesquioxane-based polymer, and that can give a cured product that has good curability and high strength.

As a result of intensive research conducted by the present inventors to solve the above problems, they discovered that the above problems can be solved by using a specific curing catalyst in a system containing a polyoxyalkylene polymer having a specific reactive silyl group and a polysilsesquioxane polymer having a specific substituent on the silicon atom, and thus arrived at the present invention.

That is, the present invention relates to a curable resin composition comprising: (A) a polyoxyalkylene polymer having a reactive silyl group represented by the following general formula (1); (B) a polysilsesquioxane polymer having an alkoxysilyl group and/or a silanol group, and further having an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms on a silicon atom; and (C) at least one curing catalyst selected from the group consisting of tin compounds having a structure in which a carbonyloxy group is bonded to a tin atom, carboxylic acids, and compounds having an amidine skeleton, wherein the content of the polyoxyalkylene polymer (A) in the curable resin composition is 10 to 90% by weight.
-Si(R ¹ )(X) ₂ (1)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. Each X independently represents a hydroxyl group or a hydrolyzable group.)
Preferably, the content of the polyoxyalkylene polymer (H) having a reactive silyl group represented by the following general formula (1') is 0% by weight or more and less than 10% by weight.
-Si(X') ₃ (1')
(In the formula, each X' independently represents a hydroxyl group or a hydrolyzable group.)
Preferably, the proportion of the polysilsesquioxane polymer (B) in the total of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B) is 1 to 60% by weight.
Preferably, the content of the curing catalyst (C) is 0.1 to 10 parts by weight based on 100 parts by weight of the total of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B).
Preferably, the molar ratio of the alkyl group to the aryl group (alkyl group:aryl group) in the polysilsesquioxane polymer (B) is 10:90 to 90:10.
Preferably, the tin compound containing a structure in which a carbonyloxy group is bonded to a tin atom is represented by the following general formula (8) or (9).
Sn( ^OCOR3 ) ₂ (8)
(R ⁴ ) ₂ Sn(OCOR ³ ) ₂ (9)
(In the formula, ^R3 may be the same or different and may represent a substituted or unsubstituted, saturated or unsaturated hydrocarbon group. ^R4 may be the same or different and may represent a substituted or unsubstituted, saturated or unsaturated hydrocarbon group.)
The present invention also relates to a sealant or adhesive containing the curable composition, or a cured product obtained by curing the curable resin composition.

According to the present invention, it is possible to provide a curable resin composition that contains an organic polymer having a reactive silyl group and a polysilsesquioxane-based polymer, and that can give a cured product that has good curability and high strength.

The embodiments of the present invention will be described in detail below.
The curable resin composition according to the present disclosure contains at least a polyoxyalkylene polymer (A) having a reactive silyl group, and a polysilsesquioxane polymer (B).

<<Reactive Silyl Group-Containing Polyoxyalkylene Polymer (A)>>
The reactive silyl group-containing polyoxyalkylene polymer (A) has a polymer backbone composed of a plurality of repeating units and a terminal structure bonded to the end of the polymer backbone. The polymer backbone means a polymer main chain composed of a plurality of repeating units. The polymer backbone of the polymer (A) may be either a straight chain or a branched chain.

The polymer skeleton is preferably a polymer skeleton composed only of a plurality of repeating units linked together, or a polymer skeleton composed only of the plurality of repeating units and a structure derived from an initiator used during polymerization. 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.

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. The terminal structure is preferably bonded to an oxyalkylene unit located at the end of the polymer skeleton via an oxygen atom. The reactive silyl group possessed by polymer (A) 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.

<Reactive silyl group>
The polyoxyalkylene polymer (A) has a reactive silyl group. The reactive silyl group refers to a silicon-containing group that has a hydroxyl group or a hydrolyzable group on a silicon atom and can form a siloxane bond by hydrolysis/dehydration condensation reaction. The polyoxyalkylene polymer (A) according to this embodiment has a reactive silyl group in which two hydroxyl groups or hydrolyzable groups are bonded to one silicon atom. The reactive silyl group is represented by the following general formula (1).
-Si(R ¹ )(X) ₂ (1)
In formula (1), R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, which may have a hetero-containing group, and each X independently represents a hydroxyl group or a hydrolyzable group.

^R1 is a hydrocarbon group having 1 to 20 carbon atoms. The number of carbon atoms is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 1 to 4. The hydrocarbon group may be an unsubstituted hydrocarbon group or a hydrocarbon group having a substituent.

The hetero-containing group that the hydrocarbon group represented by ^R1 may have as a substituent is a group containing a hetero atom, where the hetero atom is an atom other than carbon and hydrogen atoms.

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

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

Specific examples of the hydrocarbon group having 1 to 20 carbon atoms as R ¹ include alkyl groups such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, a n-hexyl group, a n-heptyl group, a n-octyl group, a 2-ethyl-n-hexyl group, a n-nonyl group, a n-decyl group, a n-undecyl group, a n-dodecyl group, a n-tridecyl group, a n-tetradecyl group, a n-pentadecyl group, a n-hexadecyl group, a n-octadecyl group, a n-nonadecyl group, and a n-icosyl group. alkenyl groups such as vinyl, 2-propenyl, 3-butenyl, and 4-pentenyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; aryl groups such as phenyl, naphthalene-1-yl, naphthalene-2-yl, o-phenylphenyl, m-phenylphenyl, and p-phenylphenyl; and aralkyl groups such as benzyl, phenethyl, naphthalene-1-ylmethyl, and naphthalene-2-ylmethyl. Groups in which these hydrocarbon groups are substituted with the aforementioned hetero-containing groups are also preferred as R ¹ .

Suitable examples of ^R1 include alkyl groups such as methyl and ethyl groups, alkyl groups having a hetero-containing group such as chloromethyl and methoxymethyl groups, cycloalkyl groups such as cyclohexyl groups, aryl groups such as phenyl groups, aralkyl groups such as benzyl groups, etc. ^R1 is preferably a methyl group, a methoxymethyl group, or a chloromethyl group, more preferably a methyl group or a methoxymethyl group, and even more preferably a methyl group.

Examples of X include hydroxyl, hydrogen, halogen, alkoxy, acyloxy, ketoximate, amino, amide, acid amide, aminooxy, mercapto, and alkenyloxy groups. Among these, alkoxy groups are preferred because they are mildly hydrolyzable and easy to handle, and methoxy and ethoxy groups are more preferred.

Specific examples of the reactive silyl group include, but are not limited to, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a dimethoxyethylsilyl group, a (chloromethyl)dimethoxysilyl group, a (chloromethyl)diethoxysilyl group, a (methoxymethyl)dimethoxysilyl group, a (methoxymethyl)diethoxysilyl group, a (N,N-diethylaminomethyl)dimethoxysilyl group, and a (N,N-diethylaminomethyl)diethoxysilyl group. Of these, the dimethoxymethylsilyl group is preferred from the viewpoint of stability.

The average number of reactive silyl groups per molecule of the polyoxyalkylene polymer (A) is preferably more than 1.0, more preferably 1.3 or more, and even more preferably 1.6 or more. The upper limit of the average number is not particularly limited, but is preferably 6 or less, and more preferably 5 or less. The average number of reactive silyl groups per molecule of the polymer (A) can be calculated from the results of NMR measurement.

In the polyoxyalkylene polymer (A), 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 (2).

-O-R ⁶ -CH(R ⁷ )-CH ₂ -Si(R ¹ )(X) ₂ (2)
In formula (2), R ⁶ represents a direct bond or a divalent hydrocarbon group having 1 to 4 carbon atoms, and R ⁷ represents hydrogen or an alkyl group having 1 to 6 carbon atoms. The oxygen atom at the left end is ^{R 1} and X are as defined above for formula (1), and represent an oxygen atom in a repeat unit located at the end of the polymer backbone or an oxygen atom bonded to a repeat unit located at the end of the polymer backbone. is the same as:

^R6 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, an ethylene group, a propylene group, or a butylene group can be used. A methylene group is particularly preferred.

^R7 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 a methyl group, an ethyl group, a propyl group, and a butyl group. ^R7 is preferably hydrogen, a methyl group, or an ethyl group, more preferably hydrogen or a methyl group.

Polymer Backbone
Examples of the polymer skeleton of the polyoxyalkylene polymer (A) include polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer, polyoxypropylene-polyoxybutylene copolymer, etc. Each polymer may be mixed in a block form, a graft form, etc. Among these, polyoxypropylene is particularly preferred. The polyoxyalkylene polymer (A) preferably contains 50% by weight or more, more preferably 70% by weight or more of the polyoxyalkylene repeating unit in the polymer skeleton.

The polyoxyalkylene polymer (A) may be a polymer having any one type of polymer backbone, or a mixture of two or more polymers having different polymer backbones. The mixture may be a mixture of polymers produced separately, or may be a mixture produced simultaneously to obtain any mixture composition.

The number average molecular weight of the polyoxyalkylene polymer (A) is not particularly limited, but is preferably 3,000 to 100,000, more preferably 3,000 to 50,000, and particularly preferably 3,000 to 30,000, as calculated as polystyrene equivalent by GPC. When the number average molecular weight is within the above range, the amount of reactive silyl groups introduced is appropriate, and it is possible to relatively easily produce a polyoxyalkylene polymer (A) that has a manageable viscosity and excellent workability while keeping production costs within an appropriate range.

The molecular weight of the polyoxyalkylene polymer (A) can be expressed as the end group-equivalent molecular weight obtained by directly measuring the end group concentration of the polymer precursor before the introduction of reactive silyl groups by titration analysis based on the principles of the hydroxyl value measurement method of JIS K 1557 and the iodine value measurement method specified in JIS K 0070, and taking into consideration the structure of the polymer (the degree of branching determined by the polymerization initiator used). The end group-equivalent molecular weight of the polyoxyalkylene polymer (A) can also be obtained by creating a calibration curve of the number average molecular weight obtained by general GPC measurement of the polymer precursor and the above end group-equivalent molecular weight, and converting the number average molecular weight obtained by GPC of the polyoxyalkylene polymer (A) into the end group-equivalent molecular weight.

The molecular weight distribution (Mw/Mn) of the polyoxyalkylene polymer (A) 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, particularly preferably 1.4 or less, even more particularly preferably 1.3 or less, and most particularly preferably 1.2 or less. The molecular weight distribution of the polyoxyalkylene polymer (A) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

<Method for producing reactive silyl group-containing polyoxyalkylene polymer (A)>
Next, a method for producing the reactive silyl group-containing polyoxyalkylene polymer (A) will be described. The reactive silyl group-containing polyoxyalkylene polymer (A) can be produced by introducing a reactive silyl group into a precursor polymer to which a reactive silyl group can be introduced. Specifically, the polyoxyalkylene polymer (A) can be produced by introducing a carbon-carbon unsaturated bond into a polyoxyalkylene polymer (P) having a hydroxyl group at its terminal by utilizing the reactivity of the hydroxyl group to obtain a precursor polymer having a carbon-carbon unsaturated bond, and then reacting the precursor polymer with a reactive silyl group-containing compound that is reactive with the carbon-carbon unsaturated bond to introduce the reactive silyl group.

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

Examples of initiators having a hydroxyl group include, but are not limited to, ethylene glycol, propylene glycol, glycerin, pentaerythritol, low molecular weight polyoxypropylene glycol, low molecular weight polyoxypropylene triol, butanol, allyl alcohol, low molecular weight polyoxypropylene monoallyl ether, and low molecular weight polyoxypropylene monoalkyl ether.

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. Propylene oxide is preferred.

(Reaction with alkali metal salts)
When introducing a carbon-carbon unsaturated bond into a polyoxyalkylene polymer (P) having a hydroxyl group at its terminal, it is preferable to first react an alkali metal salt with the polyoxyalkylene polymer (P) to convert the terminal hydroxyl group into a metaloxy group. Also, a composite metal cyanide complex catalyst can be used instead of the alkali metal salt. In this manner, a metaloxy group-terminated polyoxyalkylene polymer (D) is formed.

The alkali metal salt is not particularly limited, but examples thereof include sodium hydroxide, sodium alkoxide, potassium hydroxide, potassium alkoxide, lithium hydroxide, lithium alkoxide, cesium hydroxide, and cesium alkoxide. The alkali metal salt may be dissolved in a solvent and then subjected to the reaction.

(Reaction with electrophile (E))
Next, the metaloxy group-terminated polyoxyalkylene polymer (D) is reacted with an electrophilic agent (E) having a carbon-carbon unsaturated bond to convert the metaloxy group into a structure containing a carbon-carbon unsaturated bond, thereby forming a polyoxyalkylene polymer (F) having a carbon-carbon unsaturated bond in the terminal structure.

The electrophile (E) having a carbon-carbon unsaturated bond is not particularly limited as long as it is a compound that can react with the metaloxy group of the polyoxyalkylene polymer (D) and introduce a carbon-carbon unsaturated bond into the polyoxyalkylene polymer, but examples of such an electrophile include an organic halide (E1) having a carbon-carbon unsaturated bond and an epoxy compound (E2) having a carbon-carbon unsaturated bond.

The organic halide (E1) having a carbon-carbon unsaturated bond reacts with the metaloxy group through a halogen substitution reaction to form an ether bond, thereby introducing a structure containing a carbon-carbon unsaturated bond as the terminal structure of the polyoxyalkylene polymer.

The organic halide (E1) having a carbon-carbon unsaturated bond is preferably a halogenated hydrocarbon compound having a carbon-carbon double bond. The polyoxyalkylene polymer (G) obtained by reacting the compound has a carbon-carbon double bond at the end of the polymer skeleton. The halogenated hydrocarbon compound having a carbon-carbon double bond can be represented by, but is not limited to, the following general formula (7).
Z-R ⁶ -C(R ⁷ )=CH ₂ (7)

In formula (7), ^R6 and ^R7 are the same groups as ^R6 and ^R7 described above in relation to general formula (2). Z represents a halogen atom. When a reactive silyl group, which will be described later, is introduced into the polyoxyalkylene polymer (F) having a carbon-carbon unsaturated bond in a terminal structure obtained by reacting the organic halide (E1), the terminal structure represented by general formula (2) can be formed.

Specific examples of the halogenated hydrocarbon compound 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, and methallyl iodide. Allyl chloride and methallyl chloride are preferred because of ease of handling. Furthermore, methallyl chloride, methallyl bromide, and methallyl iodide are preferred because they improve the average ratio of the number of reactive silyl groups to the number of terminals of the polymer skeleton.

The epoxy compound (E2) having a carbon-carbon unsaturated bond reacts with the metaloxy group through a ring-opening addition reaction of the epoxy group to form an ether bond, and can introduce a structure containing a carbon-carbon unsaturated bond and a hydroxyl group as a terminal structure of the polyoxyalkylene polymer. In the ring-opening addition reaction, one or more epoxy compounds (E2) can be added to one metaloxy group by adjusting the amount of epoxy compound (E2) used relative to the metaloxy group and the reaction conditions.

The epoxy compound (E2) having a carbon-carbon unsaturated bond is not limited, but is preferably an epoxy compound having a carbon-carbon double bond. Specifically, allyl glycidyl ether, methallyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, and butadiene monoxide are preferred from the viewpoint of reaction activity, with allyl glycidyl ether being particularly preferred.

As described above, when the epoxy compound (E2) having a carbon-carbon unsaturated bond is reacted with the metaloxy group-terminated polyoxyalkylene polymer (D), new metaloxy groups are generated by ring-opening of the epoxy group. Therefore, after reacting with the epoxy compound (E2), it is also possible to continuously react with an organic halide (E1) having a carbon-carbon unsaturated bond. This method is preferable because it can further increase the amount of carbon-carbon unsaturated bonds and reactive silyl groups introduced into the polymer.

(Introduction of reactive silyl group)
The polyoxyalkylene polymer (F) (precursor polymer) having a carbon-carbon unsaturated bond in its terminal structure obtained as described above can be subjected to a hydrosilylation reaction with a hydrosilane compound (G) having a reactive silyl group, thereby introducing a reactive silyl group into the polymer. This allows the production of a polyoxyalkylene polymer (A) containing a reactive silyl group. The hydrosilylation reaction has the advantages that it can be easily carried out, the amount of reactive silyl group introduced can be easily adjusted, and the physical properties of the resulting polymer are stable.

Specific examples of the hydrosilane compound (G) having a reactive silyl group include halosilanes such as dichloromethylsilane, dichlorophenylsilane, (chloromethyl)dichlorosilane, (dichloromethyl)dichlorosilane, (methoxymethyl)dichlorosilane, and (dimethoxymethyl)dichlorosilane; dimethoxymethylsilane, diethoxymethylsilane, dimethoxyphenylsilane, ethyldimethoxysilane, (chloromethyl)dimethoxysilane, (chloromethyl)diethoxysilane, (methoxymethyl)dimethoxysilane, (methoxymethyl)diethoxysilane, and (ethoxymethyl)diethoxysilane. Examples of such silanes include alkoxysilanes such as (3,3,3-trifluoropropyl)dimethoxysilane, (N,N-diethylaminomethyl)dimethoxysilane, and (N,N-diethylaminomethyl)diethoxysilane; acyloxysilanes such as diacetoxymethylsilane and diacetoxyphenylsilane; ketoximate silanes such as bis(dimethylketoximate)methylsilane and bis(cyclohexylketoximate)methylsilane; and isopropenyloxysilanes (deacetone type) such as (chloromethyl)diisopropenyloxysilane and (methoxymethyl)diisopropenyloxysilane.

The hydrosilylation reaction is preferably carried out in the presence of a hydrosilylation catalyst in order to promote the reaction. Known examples of the hydrosilylation catalyst include metals such as cobalt, nickel, iridium, platinum, palladium, rhodium, and ruthenium, and complexes thereof. Specific examples of such platinum complexes include platinum supported on a carrier such as alumina, silica, or carbon black; chloroplatinic acid; chloroplatinic acid complexes composed of chloroplatinic acid and an alcohol, aldehyde, or ketone; platinum-olefin complexes (e.g., Pt( _CH2 = _CH2 ) ₂ ( _PPh3 ), Pt( _CH2 = _CH2 ) _2Cl2 ); platinum-vinylsiloxane complexes (e.g., Pt{(vinyl _{) Me2SiOSiMe2} (vinyl)}, Pt{Me(vinyl) _SiO } ₄ ); platinum-phosphine complexes (e.g., Ph( _PPh3 ) ₄ , Pt( _PBu3 ) ₄ ); platinum-phosphite complexes (e.g., Pt{P(OPh) ₃ } ₄ ). From the standpoint of reaction efficiency, platinum catalysts such as chloroplatinic acid and platinum vinylsiloxane complexes are preferred.

The content of polyoxyalkylene polymer (A) in the curable resin composition according to the present disclosure is 10 to 90% by weight. By including polyoxyalkylene polymer (A) in such a ratio, it is possible to form a cured product that has good curability and high strength. The content is preferably 15 to 80% by weight, more preferably 20 to 70% by weight, and even more preferably 25 to 60% by weight.

The curable resin composition according to the present disclosure may contain, in addition to the polyoxyalkylene polymer (A), a polyoxyalkylene polymer (H) having a reactive silyl group represented by the following general formula (1').
-Si(X') ₃ (1')
In formula (1'), X' each independently represents a hydroxyl group or a hydrolyzable group. Specific examples of X' include the same groups as the specific examples of X described above. In the reactive silyl group represented by formula (1'), three hydroxyl groups or hydrolyzable groups are bonded to one silicon atom.

However, since such a polyoxyalkylene polymer (H) having a reactive silyl group may impair the effects of the invention, its content is preferably small. Specifically, the content of the polyoxyalkylene polymer (H) in the curable resin composition according to the present disclosure is preferably 0% by weight or more and less than 10% by weight, more preferably 0 to 5% by weight, and even more preferably 0 to 1% by weight. The curable resin composition according to the present disclosure does not need to contain the polyoxyalkylene polymer (H).

<<Polysilsesquioxane-based polymer (B)>>
The polysilsesquioxane polymer is a siloxane polymer represented by the composition formula (RSiO _1.5 ) _n , and is a hydrolysis condensate of an alkoxysilane component containing at least an organotrialkoxysilane. The polysilsesquioxane polymer (B) in the present disclosure has both an alkyl group having 1 to 10 carbon atoms bonded to a silicon atom and an aryl group having 6 to 12 carbon atoms bonded to a silicon atom. This improves the compatibility of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B), and also improves the co-condensation property by bringing the curing rates of both polymers closer to each other, making it possible to form a cured product exhibiting high strength.

Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, and a decyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, even more preferably 1 to 2, and particularly preferably 1. The alkyl group may have no substituent, or may have a halogen atom, an alkoxy group, an acyl group, or other hetero-containing group as a substituent. The alkyl group may be of one type, or may be of two or more types in combination.

Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. The number of carbon atoms in the aryl group is preferably 6 to 10, more preferably 6 to 8, even more preferably 6 to 7, and particularly preferably 6. The aryl group may have no substituent, or may have a hetero-containing group such as a halogen atom, an alkoxy group, or an acyl group as a substituent. The aryl group may be of one type, or may be of two or more types in combination.

The molar ratio of the alkyl group and the aryl group (alkyl group:aryl group) on the silicon atom of the polysilsesquioxane polymer (B) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 70:30, from the viewpoint of the strength of the cured product obtained by curing the curable resin composition.

The polysilsesquioxane polymer (B) further has an alkoxysilyl group and/or a silanol group. By having these alkoxysilyl groups and/or silanol groups, the polysilsesquioxane polymer (B) can exhibit curing properties due to hydrolysis and dehydration condensation reactions together with the polyoxyalkylene polymer (A).

The alkoxysilyl groups that the polysilsesquioxane polymer (B) may have are some alkoxy groups that were contained in the organotrialkoxysilane raw material and remained unreacted during the production of the polysilsesquioxane polymer (B). The alkoxysilyl groups may be, for example, alkoxysilyl groups having 1 to 3 carbon atoms. Specific examples include methoxysilyl groups, ethoxysilyl groups, and propoxysilyl groups, with methoxysilyl groups and ethoxysilyl groups being preferred, and methoxysilyl groups being more preferred. The alkoxysilyl groups may be of one type only, or may be of two or more types mixed together.

The silanol groups (-SiOH) that the polysilsesquioxane polymer may have are those that are generated when some of the alkoxy groups contained in the organotrialkoxysilane raw material are hydrolyzed during the production of the polysilsesquioxane polymer (B) and then do not undergo a dehydration condensation reaction, i.e., do not form a siloxane bond and remain.

The organotrialkoxysilane used as a raw material for the polysilsesquioxane polymer (B) refers to a silane compound having one organic group bonded to a silicon atom and three alkoxy groups bonded to the silicon atom, and is represented by the formula RSi(OR') ₃ . In the formula, R represents the organic group, and OR' represents an alkoxy group. The organic group refers to an organic group other than an alkoxy group, and includes at least both the above-mentioned alkyl group having 1 to 10 carbon atoms and the above-mentioned aryl group having 6 to 12 carbon atoms.

The alkoxy group OR' bonded to a silicon atom is the same as the alkoxy group in the alkoxysilyl group that the polysilsesquioxane polymer (B) may have, and specifically may be an alkoxy group having 1 to 3 carbon atoms. Specific examples include a methoxy group, an ethoxy group, and a propoxy group, with a methoxy group and an ethoxy group being preferred, and a methoxy group being more preferred. The alkoxy group may be of only one type, or may be of two or more types mixed together.

As the organotrialkoxysilane, at least both an organotrialkoxysilane in which the organic group is an alkyl group and an organotrialkoxysilane in which the organic group is an aryl group are used.

Specific examples of organotrialkoxysilanes in which the organic group is an alkyl group include, but are not limited to, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltriisopropoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, pentyltriisopropoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, and decyltrimethoxysilane. Among these, methyltrialkoxysilane is preferred, and methyltrimethoxysilane is particularly preferred.

Specific examples of organotrialkoxysilanes in which the organic group is an aryl group include, but are not limited to, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrippropoxysilane, tolyltrimethoxysilane, tolyltriethoxysilane, tolyltrippropoxysilane, xylyltrimethoxysilane, xylyltriethoxysilane, xylyltrippropoxysilane, naphthyltrimethoxysilane, naphthyltriethoxysilane, naphthyltrippropoxysilane, etc. Among these, phenyltrialkoxysilane is preferred, and phenyltrimethoxysilane is particularly preferred.

In the alkoxysilane component, the molar ratio (alkyl group:aryl group) of the organotrialkoxysilane in which the organic group is an alkyl group to the organotrialkoxysilane in which the organic group is an aryl group is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 70:30, from the viewpoint of the strength of the cured product obtained by curing the curable resin composition.

In the alkoxysilane component, the total ratio of organotrialkoxysilanes whose organic group is an alkyl group and organotrialkoxysilanes whose organic group is an aryl group is preferably 80 to 100 mol%, more preferably 90 to 100 mol%, even more preferably 95 to 100 mol%, and particularly preferably 99 to 100 mol%, from the viewpoint of the physical properties exhibited by the polysilsesquioxane polymer (B). Examples of alkoxysilanes other than organotrialkoxysilanes whose organic group is an alkyl group and organotrialkoxysilanes whose organic group is an aryl group include organotrialkoxysilanes whose organic group does not fall into either of the alkyl group and aryl group, diorganodialkoxysilanes, triorganomonoalkoxysilanes, and tetraalkoxysilanes.

The number average molecular weight of the polysilsesquioxane polymer (B) is preferably 400 to 10,000, and more preferably 500 to 5,000. The number average molecular weight of the polysilsesquioxane polymer (B) can be measured by GPC.

The polysilsesquioxane polymer (B) can be produced by subjecting an alkoxysilane component containing the organotrialkoxysilane to hydrolysis and dehydration condensation reactions in the presence of water and, if necessary, a condensation catalyst. During the reaction, some of the alkoxy groups contained in the alkoxysilane component remain unreacted, and/or after the alkoxy groups have undergone the hydrolysis reaction, they remain without undergoing the dehydration condensation reaction, and the produced polysilsesquioxane polymer has alkoxysilyl groups and/or silanol groups.

The hydrolysis and dehydration condensation reactions are preferably carried out with the addition of water. In this case, the amount of alkoxysilyl groups and/or silanol groups in the resulting polysilsesquioxane polymer and the molecular weight of the polysilsesquioxane polymer can be controlled by adjusting the amount of water used. From this perspective, the amount of water used is preferably 30 mol% to 50 mol%, more preferably 32 mol% to 49 mol%, and even more preferably 35 mol% to 45 mol%, based on the total number of moles of alkoxy groups on silicon atoms contained in the alkoxysilane component (100%).

The hydrolysis and dehydration condensation reactions are preferably carried out in the presence of a condensation catalyst to promote the reaction. As the condensation catalyst, a known catalyst can be used. Specific examples include basic catalysts, acidic catalysts, and neutral salts. As the condensation catalyst, acidic catalysts and neutral salts are preferred, and neutral salts are more preferred, because they improve the storage stability of the resulting polysilsesquioxane polymer.

As the acid catalyst, organic acids are preferred from the viewpoint of compatibility with the alkoxysilane component, and phosphate esters and carboxylic acids are more preferred. Specific examples of organic acids include ethyl acid phosphate, butyl acid phosphate, dibutyl pyrophosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, isotridecyl acid phosphate, dibutyl phosphate, bis(2-ethylhexyl) phosphate, formic acid, acetic acid, butyric acid, and isobutyric acid.

Examples of basic catalysts include amine compounds such as N-ethylmorpholine, N-methyldiethanolamine, N-ethyldiethanolamine, N-n-butyldiethanolamine, N-t-butyldiethanolamine, triethylamine, n-butylamine, hexylamine, triethanolamine, diazabicycloundecene, and ammonia, as well as metal hydroxides such as sodium hydroxide and potassium hydroxide.

A neutral salt is a positive salt consisting of a strong acid and a strong base, and is, for example, a salt consisting of a combination of a cation selected from the group consisting of a Group 1 element ion, a Group 2 element ion, a tetraalkylammonium ion, and a guanidinium ion, and an anion selected from the group consisting of a Group 17 element ion excluding fluoride ion, a sulfate ion, a nitrate ion, and a perchlorate ion. In particular, Group 17 element ions are preferred as anions because of their high nucleophilicity, and Group 1 element ions and Group 2 element ions are preferred as cations because they are not bulky and do not inhibit the nucleophilic action.

Specific compounds of neutral salts are not particularly limited, but preferred examples include lithium chloride, sodium chloride, potassium chloride, rabidium chloride, cesium chloride, magnesium chloride, calcium chloride, strontium chloride, lithium bromide, sodium bromide, potassium bromide, rabidium bromide, cesium bromide, magnesium bromide, calcium bromide, strontium bromide, lithium iodide, sodium iodide, potassium iodide, rabidium iodide, cesium iodide, magnesium iodide, calcium iodide, and strontium iodide.

The amount of condensation catalyst added can be adjusted as appropriate, but may be, for example, about 50 ppm to 3% by weight based on the alkoxysilane component. However, in order to improve the stability of the polysilsesquioxane polymer (B), it is preferable to use a smaller amount of condensation catalyst within the range in which the effect of shortening the reaction time by the condensation catalyst is achieved.

The reaction temperature when carrying out the hydrolysis and dehydration condensation steps can be appropriately set by those skilled in the art, but for example, it is preferable to heat the reaction liquid to a range of 50 to 110°C. In addition, the reaction time when carrying out the hydrolysis and dehydration condensation steps can be appropriately set by those skilled in the art, but may be, for example, about 10 minutes to 12 hours.

The content of the polysilsesquioxane-based polymer (B) in the curable resin composition according to the present disclosure can be appropriately determined taking into consideration the curability of the composition and the strength of the resulting cured product, but the content of the polysilsesquioxane-based polymer (B) in the total of the polyoxyalkylene-based polymer (A) and the polysilsesquioxane-based polymer (B) is preferably 1 to 60% by weight, more preferably 5 to 50% by weight, even more preferably 10 to 45% by weight, and particularly preferably 15 to 40% by weight.

After producing the polysilsesquioxane polymer (B), a step of removing alcohol generated by hydrolysis of the alkoxysilane component during the production may be carried out. This step is preferably carried out after mixing the polyoxyalkylene polymer (A) with the polysilsesquioxane polymer (B) containing the alcohol. This makes it possible to obtain a mixture in which the content of volatile components such as alcohol is reduced while uniformly mixing the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B). The alcohol removal step can be carried out by subjecting the mixture to reduced pressure distillation to remove the alcohol. The conditions for the reduced pressure distillation can be appropriately set by a person skilled in the art, but the temperature may be, for example, about 60 to 160°C.

<<Curing catalyst (C)>>
The curable resin composition according to the present disclosure is a curing reaction that causes hydrolysis and dehydration condensation of reactive silyl groups contained in the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B). In order to obtain a cured product having good curability and high strength, the curing catalyst (C) is a tin-based curing agent having a carbonyloxy group bonded to a tin atom. A tin compound having the structure, a carboxylic acid, or a compound having an amidine skeleton is used. These curing catalysts may be used alone or in combination of two or more.

When a polyoxyalkylene polymer (A) having a reactive silyl group represented by the general formula (1) is compared with a polysilsesquioxane polymer (B), the latter has a considerably faster curing rate. Therefore, when the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B) are cured in the presence of a curing catalyst such as dibutyltin bisacetylacetonate, curing of only the polysilsesquioxane polymer (B) proceeds preferentially, resulting in the formation of a cured product that is weak in strength and brittle.
However, when the above-mentioned specific curing catalyst (C) is used, the curing rates of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B) become close to each other, and the curing proceeds relatively uniformly, making it possible to form a cured product exhibiting high strength.

The tin compound containing a structure in which a carbonyloxy group is bonded to a tin atom, which is one type of curing catalyst (C), is a tin salt of a carboxylic acid and can be represented, for example, by the following general formula (8) or (9).
Sn( ^OCOR3 ) ₂ (8)
(R ⁴ ) ₂ Sn(OCOR ³ ) ₂ (9)

In formula (8) or (9), R ³ is the same or different, and represents a substituted or unsubstituted, saturated or unsaturated hydrocarbon group. R ⁴ is the same or different, and represents a substituted or unsubstituted, saturated or unsaturated hydrocarbon group. The number of carbon atoms of the hydrocarbon group represented by ^{R 3} is preferably 1 to 20, more preferably 6 to 18, and more preferably 8 to 12. The number of carbon atoms of the hydrocarbon group represented by ^{R 4} is preferably 1 to 20, more preferably 2 to 16, and more preferably 3 to 10. In each formula, the portion of OCOR ³ corresponds to the carbonyloxy group. The tin compound is a tin salt of a carboxylic acid. As the carboxylic acid constituting the tin compound, various carboxylic acids exemplified later for the carboxylic acid which is one of the curing catalysts (C) can be used.

Specific examples of the tin compounds include dialkyltin carboxylates such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diethylhexanoate, dibutyltin dioctanoate, dibutyltin bis(methyl maleate), dibutyltin bis(ethyl maleate), dibutyltin bis(butyl maleate), dibutyltin bis(isooctyl maleate), dibutyltin bis(tridecyl maleate), dibutyltin bis(benzyl maleate), dioctyltin diacetate, dioctyltin distearate, dioctyltin dilaurate, dioctyltin bis(ethyl maleate), and dioctyltin bis(isooctyl maleate); and divalent tin compounds such as tin octylate, tin naphthenate, and tin stearate.

The carboxylic acid, which is one of the curing catalysts (C), is not particularly limited, but a monovalent, divalent, or trivalent carboxylic acid can be used. Among these, a monovalent or divalent carboxylic acid is preferred, and a monovalent carboxylic acid is more preferred. Either an aliphatic carboxylic acid or an aromatic carboxylic acid can be used, but an aliphatic carboxylic acid is preferred. The aliphatic carboxylic acid may be either a saturated fatty acid or an unsaturated fatty acid. The hydrocarbon group in the carboxylic acid group may be a straight chain or a branched chain. The number of carbon atoms in the carboxylic acid may be, for example, 1 to 20, preferably 6 to 18, and more preferably 8 to 12. The carboxylic acid may have a functional group other than a carboxyl group, but preferably does not have a functional group other than a carboxyl group.

Specific examples of the carboxylic acid include formic acid; straight-chain saturated fatty acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, and lacteric acid; undecylenic acid, linderic acid, tsuzuic acid, physeteric acid, myristoleic acid, 2-hexadecenoic acid, 6-hexadecenoic acid, 7-hexadecenoic acid, and palmitoleic acid. Monoenoic unsaturated fatty acids such as petroselinic acid, oleic acid, elaidic acid, asclepinic acid, vaccenic acid, gadoleic acid, gondoic acid, cetoleic acid, erucic acid, brassidic acid, selacoleic acid, xymenic acid, lumecic acid, acrylic acid, methacrylic acid, angelic acid, crotonic acid, isocrotonic acid, and 10-undecenoic acid; linoelaidic acid, linoleic acid, 10,12-octadecadienoic acid, hiragoic acid, α-eleostearic acid, β-eleostearic acid, punicic acid, linolenic acid, 8,11,14-eicosatrienoic acid, 7,10,13-docosatrienoic acid, and 4,8,11,14-hexadecatetraenoic acid; Polyenic unsaturated fatty acids such as moroctic acid, stearidonic acid, arachidonic acid, 8,12,16,19-docosatetraenoic acid, 4,8,12,15,18-eicosapentaenoic acid, sardine acid, herring acid, and docosahexaenoic acid; branched fatty acids such as 1-methylbutyric acid, isobutyric acid, 2-ethylbutyric acid, isovaleric acid, tuberculostearic acid, pivalic acid, and neodecanoic acid; fatty acids with triple bonds such as propiolic acid, talic acid, stearic acid, crepenic acid, xymenic acid, and 7-hexadecanoic acid; alicyclic carboxylic acids such as naphthenic acid, malvalic acid, sterculic acid, hydnocarbic acid, shormooglic acid, and golric acid. carboxylic acids; oxygen-containing fatty acids such as acetoacetic acid, ethoxyacetic acid, glyoxylic acid, glycolic acid, gluconic acid, savinic acid, 2-hydroxytetradecanoic acid, iprolic acid, 2-hydroxyhexadecanoic acid, yarapinolic acid, uniperilic acid, ambrettolic acid, alluritic acid, 2-hydroxyoctadecanoic acid, 12-hydroxyoctadecanoic acid, 18-hydroxyoctadecanoic acid, 9,10-dihydroxyoctadecanoic acid, ricinoleic acid, camrolenoic acid, licanic acid, ferronic acid, and cerebronic acid; and halogen-substituted monocarboxylic acids such as chloroacetic acid, 2-chloroacrylic acid, and chlorobenzoic acid. Further, examples of the aliphatic dicarboxylic acid include saturated dicarboxylic acids such as adipic acid, azelaic acid, pimelic acid, suberic acid, sebacic acid, ethylmalonic acid, glutaric acid, oxalic acid, malonic acid, succinic acid, and oxydiacetic acid; and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, acetylenedicarboxylic acid, and itaconic acid. Examples of the aliphatic polycarboxylic acid include tricarboxylic acids such as aconitic acid, citric acid, and isocitric acid. Examples of the aromatic carboxylic acid include aromatic monocarboxylic acids such as benzoic acid, 9-anthracene carboxylic acid, atrolactic acid, anisic acid, isopropyl benzoic acid, salicylic acid, and toluic acid; and aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, carboxyphenylacetic acid, and pyromellitic acid. Further, examples of the amino acids include alanine, leucine, threonine, aspartic acid, glutamic acid, arginine, cysteine, methionine, phenylalanine, tryptophan, and histidine.

The compound having an amidine skeleton, which is one of the curing catalysts (C), can be represented by the following general formula (10).
R ¹¹ N=CR ¹² -NR ¹³ ₂ (10)
In formula (10), R ¹¹ , R ¹² and two R ¹³ each independently represent a hydrogen atom or an organic group. Any two or more of R ¹¹ , R ¹² and two R ¹³ may be bonded to form a cyclic structure.

R ¹¹ is preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms in order to enhance the curability of the curable resin composition, and more preferably a hydrocarbon group in which the carbon atom adjacent to the nitrogen atom (the carbon atom at the α-position) does not have an unsaturated bond. The number of carbon atoms in R ¹¹ is preferably 1 to 10, more preferably 1 to 6, in order to be easily available.

R ¹² is preferably a hydrogen atom or an organic group represented by -NR ¹⁴ ₂ , and more preferably an organic group represented by -NR ¹⁴ ₂ , in order to enhance the curability of the curable resin composition. However, each of the two R ¹⁴ independently represents a hydrogen atom or an organic group having 1 to 20 carbon atoms. In this case, the amidine compound represented by general formula (10) is called a guanidine compound.

In addition, R ¹² is preferably an organic group represented by -NR ¹⁵ -C(=NR ¹⁶ )-NR ¹⁷ ₂ or -N=C(NR ¹⁸ ₂ )-NR ¹⁹ ₂ , since the physical properties of the resulting cured product are good. However, R ¹⁵ , R ¹⁶ and the two R ¹⁷ each independently represent a hydrogen atom or an organic group having 1 to 6 carbon atoms. The two R ¹⁸ and the two R ¹⁹ each independently represent a hydrogen atom or an organic group having 1 to 6 carbon atoms. In this case, the amidine compound represented by general formula (10) is called a biguanide compound.

In general formula (10), the two R ¹³ preferably represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and more preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, because these are easily available and enhance the curability of the curable resin composition.

The number of carbon atoms contained in the amidine compound is preferably 2 or more, more preferably 6 or more, and particularly preferably 7 or more. There is no particular limit to the upper limit of the number of carbon atoms contained in the amidine compound, but it is preferably 10,000 or less. In addition, the molecular weight of the amidine compound is preferably 60 or more, more preferably 120 or more, and particularly preferably 130 or more. There is no particular limit to the upper limit of the molecular weight of the amidine compound, but it is preferably 100,000 or less.

The amidine compound is not particularly limited, and examples thereof include pyrimidine compounds such as pyrimidine, 2-aminopyrimidine, 6-amino-2,4-dimethylpyrimidine, 2-amino-4,6-dimethylpyrimidine, 1,4,5,6-tetrahydropyrimidine, 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine, 1-ethyl-2-methyl-1,4,5,6-tetrahydropyrimidine, 1,2-diethyl-1,4,5,6-tetrahydropyrimidine, 1-n-propyl-2-methyl-1,4,5,6-tetrahydropyrimidine, 2-hydroxy-4,6-dimethylpyrimidine, 1,3-diazanaphthalene, and 2-hydroxy-4-aminopyrimidine;
Imidazoline compounds such as 2-imidazoline, 2-methyl-2-imidazoline, 2-ethyl-2-imidazoline, 2-propyl-2-imidazoline, 2-vinyl-2-imidazoline, 1-(2-hydroxyethyl)-2-methyl-2-imidazoline, 1,3-dimethyl-2-iminoimidazolidine, and 1-methyl-2-iminoimidazolidine-4-one;
Amidine compounds such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 2,9-diazabicyclo[4.3.0]nona-1,3,5,7-tetraene, and 6-(dibutylamino)-1,8-diazabicyclo[5,4,0]undec-7-ene (DBA-DBU);
Guanidine, dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, 1,1-dimethylguanidine, 1,3-dimethylguanidine, 1,2-diphenylguanidine, 1,1,2-trimethylguanidine, 1,2,3-trimethylguanidine, 1,1,3,3-tetramethylguanidine, 1,1,2,3,3-pentamethylguanidine, 2-ethyl-1,1,3,3-tetramethylguanidine, 1,1,3,3-tetramethyl-2-n-propylguanidine, 1,1,3,3-tetramethyl-2-isopropylguanidine, 2-n-butyl-1,1,3,3-tetramethylguanidine, 2-tert-butyl-1,1,3,3-tetramethylguanidine, 1,2,3-tricyclohexylguanidine, 1-benzyl-2,3-dimethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-ethyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-n-propyl-1,5,7-triazabicyclo[4.4.0] Guanidine compounds such as dec-5-ene, 7-isopropyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-n-butyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-cyclohexyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and 7-n-octyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene;
biguanide, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-(2-ethylhexyl)biguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide, 1-morpholinobiguanide, Examples of such compounds include biguanide compounds such as 1-n-butyl-N2-ethylbiguanide, 1,1'-ethylenebisbiguanide, 1,5-ethylenebiguanide, 1-[3-(diethylamino)propyl]biguanide, 1-[3-(dibutylamino)propyl]biguanide, and N',N''-dihexyl-3,12-diimino-2,4,11,13-tetraazatetradecanediamine. Among these, guanidine compounds are preferred due to their good curability, and phenylguanidine is particularly preferred.

From the viewpoint of achieving both an improvement in the curing reaction rate and workability during curing, the amount of the curing catalyst (C) to be blended is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 15 parts by weight, even more preferably 0.1 to 10 parts by weight, even more preferably 0.5 to 7 parts by weight, and particularly preferably 1 to 5 parts by weight, per 100 parts by weight of the total of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B).

(Curing promoter)
The curable resin composition may further contain an amine compound as a curing promoter. By using such a curing promoter in combination with the curing catalyst (C), the curing speed of the curable resin composition and/or the strength of the cured product can be further improved. The effect achieved by this curing promoter is particularly remarkable when the curing catalyst (C) is the divalent tin compound or carboxylic acid.

The amine compound is an amine compound other than the compound having the amidine skeleton, and is not particularly limited, but a monovalent, divalent, or trivalent amine compound can be used. Among these, a monovalent or divalent carboxylic acid is preferred. Either an aliphatic amine compound or an aromatic amine compound can be used, but an aliphatic amine compound is preferred. The aliphatic amine compound may be either a saturated aliphatic or an unsaturated aliphatic compound. The hydrocarbon group in the aliphatic amine compound may be a straight chain or a branched chain. The carbon number of the amine compound may be, for example, 1 to 20, preferably 3 to 18, and more preferably 6 to 14. The amine compound may have a functional group other than an amino group, but preferably does not have a functional group other than an amino group.

Specific examples of the amine compounds include aliphatic primary amines such as butylamine, octylamine, 2-ethylhexylamine, laurylamine, stearylamine, and oleylamine; aliphatic secondary amines such as dibutylamine; aliphatic tertiary amines such as triethylamine, triamylamine, trihexylamine, and trioctylamine; aliphatic unsaturated amines such as triallylamine and oleylamine; aromatic amines such as aniline, laurylaniline, stearylaniline, and triphenylamine; pyridine, 2-aminopyridine, 2-(dimethylamino)pyridine, 4-(dimethylaminopyridine), 2-hydroxypyridine, imidazole, 2-ethyl-4-methylimidazole, morpholine, N-methylmorpholine, piperidine, 2-piperidinemethanol, 2-(2-piperidinemethanol), ... Nitrogen-containing heterocyclic compounds such as 1,4-diazabicyclo(2,2,2)octane (DABCO), aziridine, etc.; monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, propylenediamine, hexamethylenediamine, N-methyl-1,3-propanediamine, N,N'-dimethyl-1,3-propanediamine, diethylenetriamine, triethylenetetramine, triethylenediamine, benzylamine, 3-methoxypropylamine, 3-lauryloxypropylamine, 3-dimethylaminopropylamine, 3-diethylaminopropylamine (DEAPA), 3-dibutylaminopropylamine, 3-morpholinopropylamine, 2-(1-piperazinyl)ethylamine, xylylenediamine, etc.

The amount of the amine compound is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, even more preferably 0.05 to 3 parts by weight, and particularly preferably 0.1 to 1 part by weight, per 100 parts by weight of the total of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B), from the viewpoint of improving the curing speed and/or the strength of the cured product.

<<Curable resin composition>>
The curable resin composition according to the present disclosure contains, in addition to the polyoxyalkylene polymer (A), the polysilsesquioxane polymer (B), and the curing catalyst, various additives as necessary. The additives may include fillers, adhesion promoters, plasticizers, anti-sagging agents, antioxidants, light stabilizers, ultraviolet absorbers, physical property adjusters, compounds containing epoxy groups, photocuring agents, etc. Examples of the organic resin include an oxygen-curable substance, an oxygen-curable substance, and an organic resin other than the polyoxyalkylene polymer (A).

In addition, in order to adjust the physical properties of the curable resin composition or the cured product, additives other than those mentioned above may be added to the curable resin composition as necessary. Examples of such additives include tackifier resins, solvents, diluents, epoxy resins, surface improvers, foaming agents, curability regulators, flame retardants, silicates, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, and fungicides.

The curable resin composition can be prepared as a one-component type in which all ingredients are mixed in advance, sealed, and stored, and then cured by moisture in the air after application. The one-component curable resin composition preferably contains substantially no water, and the water content is preferably 5% by weight or less, and more preferably 1% by weight or less. It can also be prepared as a two-component type in which ingredients such as a curing catalyst, a filler, a plasticizer, and water are mixed as a curing agent, and the curing agent and a base agent containing a polyoxyalkylene polymer (A) and a polysilsesquioxane polymer (B) are mixed before use. The two-component base agent preferably contains substantially no water, and the water content is preferably 5% by weight or less, and more preferably 1% by weight or less. From the viewpoint of workability, the one-component type is preferred.

The curable resin composition is formed into a desired shape by a method such as coating, casting, or filling before curing. The curable resin composition that has been coated, cast, or filled and formed into a desired shape can be cured at room temperature, or can be cured under heat. There are no particular limitations on the heat curing conditions, but a temperature of 60 to 220°C and a time of 1 to 120 minutes are preferred, and a temperature of 100 to 200°C and a time of 5 to 60 minutes are even more preferred.

The curable resin composition according to the present disclosure can be used as an adhesive, a pressure sensitive adhesive, a sealant for sealing construction in buildings, ships, automobiles, buses, roads, home appliances, etc., a mold release agent, a paint, a spraying agent, etc. Furthermore, the cured product obtained by curing the curable resin composition can be suitably used as a waterproofing material, a coating waterproofing material, an anti-vibration material, a vibration damping material, a soundproofing material, a foaming material, etc.

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

The number average molecular weight in the examples is a GPC molecular weight measured under the following conditions.
Liquid delivery system: Tosoh HLC-8220GPC
Column: Tosoh TSK-GEL H type Solvent: THF
Molecular weight: polystyrene equivalent Measurement temperature: 40°C

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

The average number of silyl groups introduced per terminal of the polymer (A) shown in the examples was calculated by NMR measurement.

(Synthesis Example 1)
Using polyoxypropylene triol having a number average molecular weight of about 4,500 as an initiator, propylene oxide was polymerized in the presence of a zinc hexacyanocobaltate glyme complex catalyst to obtain polyoxypropylene (P-1) having a number average molecular weight of 24,600 (terminal group calculated molecular weight: 17,400) and a molecular weight distribution Mw/Mn of 1.31 having hydroxyl groups at the terminals.
Sodium methoxide was added in an amount of 1.2 molar equivalents to the hydroxyl groups of the obtained hydroxyl-terminated polyoxypropylene (P-1) as a 28% methanol solution. After distilling off the methanol by vacuum devolatilization, 1.5 molar equivalents of allyl chloride was further added to the hydroxyl groups of the polymer (P-1) to convert the terminal hydroxyl groups to allyl groups. Unreacted allyl chloride was removed by devolatilization under reduced pressure. The obtained unpurified polyoxypropylene was mixed with n-hexane and water and stirred, after which the water was removed by centrifugation, and the hexane was devolatilized under reduced pressure from the obtained hexane solution to remove the metal salts in the polymer. As a result, polyoxypropylene (Q-1) having allyl groups at its terminals was obtained.
50 μl of platinum divinyldisiloxane complex solution (3% by weight of platinum in isopropanol solution) was added to 500 g of this polymer (Q-1), and 6.4 g of dimethoxymethylsilane was slowly added dropwise while stirring. After reacting at 100° C. for 2 hours, unreacted dimethoxymethylsilane was distilled off under reduced pressure to obtain polyoxypropylene (A-1) having a number average molecular weight of 26,200 and dimethoxymethylsilyl groups at the terminals. It was found that polymer (A-1) had an average of 0.7 dimethoxymethylsilyl groups at one terminal and an average of 2.2 dimethoxymethylsilyl groups per molecule.

(Synthesis Example 2)
297.5 g of phenyltrimethoxysilane, 392.3 g of methyltrimethoxysilane, 94.3 g of water, and 0.4 g of a 10% LiBr aqueous solution were added at room temperature, and the mixture was heated and reacted for 6 hours under reflux of methanol to obtain a methanol solution of polysilsesquioxane polymer (B-1) having methoxysilyl groups and/or silanol groups, and further having phenyl groups and methyl groups on silicon atoms, and having a number average molecular weight of 900.
The polymer (A-1) obtained in Synthesis Example 1 and the above methanol solution were mixed so that the solid content ratio of (A-1):(B-1) was 70:30, and the methanol was distilled off at 140° C. to obtain a polymer mixture (AB-1).

(Examples 1 , 2, 5 to 7 , Reference Examples 3 and 4 , and Comparative Examples 1 to 4)
100 parts by weight of the polymer mixture (AB-1) and 50 parts by weight of surface-treated colloidal calcium carbonate (Shiraishi Kogyo Co., Ltd., trade name: Hakuenka CCR) were mixed and thoroughly kneaded, and then passed through a small three-roll paint roll three times. After this, dehydration was carried out under reduced pressure at 120°C for 2 hours, and after cooling to 50°C or less, 3 parts by weight of vinyltrimethoxysilane (Momentive Performance Materials, Inc., trade name: Silquest A-171), 2 parts by weight of γ-(2-aminoethyl)aminopropyltrimethoxysilane (Momentive Performance Materials, Inc., trade name: Silquest A-1120), and the curing catalyst and curing promoter shown in Table 1 were added and kneaded to obtain a curable composition.

The curing catalysts and curing promoters used in the respective Examples , Reference Examples and Comparative Examples are as follows.
Tin(II) octoate (Neostan U-28, manufactured by Nitto Chemical Industry Co., Ltd.)
Dibutyltin dilaurate (Neostan U-100, manufactured by Nitto Chemical Industry Co., Ltd.)
Dioctyltin dilaurate (Neostan U-810, manufactured by Nitto Kasei Kogyo Co., Ltd.)
Neodecanoic acid (Versatic 10, manufactured by Japan Epoxy Resins Co., Ltd.)
Phenylguanidine solution (48% BBSA solution, manufactured by Nippon Carbide Industries Co., Ltd.)
BBSA (N-n-butylbenzenesulfonamide, manufactured by Proviron)
Reaction product of dioctyltin salt and ethyl orthosilicate (Neostan S-1, manufactured by Nitto Kasei Kogyo Co., Ltd.)
Dibutyltin bisacetylacetonate (Neostan U-220H, manufactured by Nitto Chemical Industry Co., Ltd.)
Dibutyltin bis(dodecyl mercaptide) (manufactured by Nitto Chemical Industry Co., Ltd.)
Titanium ethyl acetoacetate (Orgatics TC-750, Matsumoto Fine Chemical Co., Ltd.)
Laurylamine (Wako Pure Chemical Industries, Ltd.)
3-(Diethylamino)propylamine (DEAPA, manufactured by Wako Pure Chemical Industries, Ltd.)

(Curing property)
The time when each curable composition was spread with a spatula was set as the starting time, and the surface of the composition was confirmed by touching it with the spatula, and the time until the composition no longer stuck to the spatula (skin time) was measured. The results are shown in Table 1.

(Tensile properties)
Each curable composition was cut into a 3 mm thick sheet specimen and placed at 23°C and 50% RH for 3 days, and then placed in a 50°C dryer for 4 days to completely cure. After punching out a No. 3 dumbbell, a tensile test was performed at a tensile speed of 200 mm/min using an autograph manufactured by Shimadzu Corporation to measure the breaking strength (TB). The results are shown in Table 1.

As shown in Table 1, Examples 1 , 2, 5 to 7 and Reference Examples 3 and 4 , which contained a tin compound having a structure in which a carbonyloxy group is bonded to a tin atom, a carboxylic acid, or a compound having an amidine skeleton as a curing catalyst, had relatively good curability, but the strength of the cured product was higher than that of Comparative Examples 1 to 4, which contained a curing catalyst that did not fall under any of the above compounds.

(Example 8 , Reference Example 9, and Comparative Examples 5 to 6)
As shown in Table 2, 100 parts by weight of the polymer mixture (AB-1) or polyoxypropylene (A-1), 120 parts by weight of surface-treated gelatinous calcium carbonate (Shiraishi Kogyo Co., Ltd., product name: Hakuenka CCR), 20 parts by weight of titanium oxide (Ishihara Sangyo Kaisha, Ltd., product name: Typek R-820), 55 parts by weight of a phthalate ester-based plasticizer (J-Plus Co., Ltd., product name: DIDP), 2 parts by weight of a thixotropic agent (Kusumoto Chemicals Co., Ltd., product name: Disparlon 6500), 1 part by weight of a light stabilizer (Ciba Specialty Chemicals Co., Ltd., product name: Tinuvin 770), and 1 part by weight of an ultraviolet absorbing agent (Ciba Specialty Chemicals Co., Ltd., product name: Tinuvin 326) were mixed and thoroughly kneaded, and then passed through a small three-roll paint roll three times. Thereafter, dehydration was carried out under reduced pressure at 120°C for 2 hours, and the mixture was cooled to below 50°C. Then, 2 parts by weight of vinyltrimethoxysilane (manufactured by Momentive Performance Materials, Inc., product name: Silquest A-171), 3 parts by weight of γ-(2-aminoethyl)aminopropyltrimethoxysilane (manufactured by Momentive Performance Materials, Inc., product name: Silquest A-1120) as an adhesion promoter, and a curing catalyst shown in Table 2 were added and kneaded to obtain a curable composition.
The skinning time of each curable composition was measured in the same manner as above. The results are shown in Table 2.

As shown in Table 2, Example 8 and Reference Example 9, which contain polyoxypropylene having a methyldimethoxysilyl group and a polysilsesquioxane-based polymer, show shorter skinning times than Comparative Examples 5 and 6, which contain polyoxypropylene having a methyldimethoxysilyl group but no polysilsesquioxane-based polymer. In other words, it is clear that the curing speed is improved by blending polyoxypropylene having a methyldimethoxysilyl group with a polysilsesquioxane-based polymer.

Claims (8)

A polyoxyalkylene polymer (A) having a reactive silyl group represented by the following general formula (1):
A polysilsesquioxane polymer (B) having an alkoxysilyl group and/or a silanol group, and further having an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 10 carbon atoms on a silicon atom; and
The composition contains at least one curing catalyst (C) selected from the group consisting of a tin compound having a structure in which a carbonyloxy group is bonded to a tin atom and represented by the following general formula (8) , a carboxylic acid, and a guanidine compound which is a compound having an amidine skeleton:
The content of the polyoxyalkylene polymer (A) in the curable resin composition is 10 to 90% by weight.
-Si(R ¹ )(X) ₂ (1)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a hetero-containing group. Each X independently represents a hydroxyl group or a hydrolyzable group.)
Sn(OCOR3 ⁾ 2 ₍ 8)
(In the formula, R3 ^is the same or different and represents a substituted or unsubstituted, saturated or unsaturated hydrocarbon group.) 2. The curable resin composition according to claim 1, wherein the content of the polyoxyalkylene polymer (H) having a reactive silyl group represented by the following general formula (1') is 0% by weight or more and less than 10% by weight.
-Si(X') ₃ (1')
(In the formula, each X' independently represents a hydroxyl group or a hydrolyzable group.) The curable resin composition according to claim 1 or 2, wherein the proportion of the polysilsesquioxane polymer (B) in the total of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B) is 1 to 60% by weight. The curable resin composition according to any one of claims 1 to 3, wherein the content of the curing catalyst (C) is 0.1 to 10 parts by weight per 100 parts by weight of the total of the polyoxyalkylene polymer (A) and the polysilsesquioxane polymer (B). The curable resin composition according to any one of claims 1 to 4, wherein the molar ratio of the alkyl group to the aryl group (the alkyl group:the aryl group) in the polysilsesquioxane polymer (B) is 10:90 to 90:10. A sealant comprising the curable resin composition according to any one of claims 1 to 5 . An adhesive comprising the curable resin composition according to any one of claims 1 to 5 . A cured product obtained by curing the curable resin composition according to any one of claims 1 to 5 .