JP7587965B2 - Curable Composition - Google Patents

Description

The present invention relates to a curable composition containing a reactive silicon group-containing polyoxyalkylene polymer in which the total number of reactive silicon groups in the terminal structure, terminal olefin groups, and internal olefin groups is on average more than 1.0 per terminal structure, and a reactive silicon group-containing polymer in which the total number of reactive silicon groups in the terminal structure, terminal olefin groups, and internal olefin groups is on average 1.0 or less per terminal structure.

Organic polymers that have at least one reactive silicon in the molecule are known to have the property of crosslinking through the formation of siloxane bonds accompanied by hydrolysis of silyl groups due to moisture, etc., even at room temperature, resulting in a rubber-like cured product. Organic polymers with polyoxyalkylene polymer main chains as organic polymers that have these reactive silicon groups are already being produced industrially and are widely used in applications such as sealants, adhesives, and paints.

Polyoxyalkylene polymers having reactive silicon groups that have one reactive silicon group at one end are often used, but polyoxyalkylene polymers having multiple reactive silicon groups at one end are also known (Patent Document 1), and blends with polyoxyalkylene polymers having one reactive silicon group at one end are also known (Patent Document 2).

It is also known to blend a polyoxyalkylene polymer having one reactive silicon group at one end with a low molecular weight polyoxyalkylene polymer having reactive silicon groups with a large number of silyl groups per molecule (Patent Document 3).

International Publication No. 2013/180203 International Publication No. 2015/080067 International Publication No. 2012/070476

The object of the present invention is to provide a curable composition that has low viscosity, good workability, and produces a cured product with high strength (high tensile strength) after curing.

As a result of extensive research into solving the above problems, the inventors have completed the following invention.

That is, the present invention provides:
[1]. General formula (1):
-Si(R ¹ ) _3-a (X) _a (1)
(In the formula, each R ¹ independently 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. a is 1, 2, or 3.)
a reactive silicon group-containing polyoxyalkylene polymer (A) having a reactive silicon group represented by the formula:
a reactive silicon group-containing polyoxyalkylene polymer (B) having a reactive silicon group represented by general formula (1), the reactive silicon group being in a terminal structure having a reactive silicon group and a terminal olefin group and/or an internal olefin group, the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure being on average 1.0 or less per terminal structure, and the number of reactive silicon groups contained in one molecule being on average 1.1 to 4.0;
A curable composition comprising:
The present invention relates to a curable composition in which a blend of a reactive silicon group-containing polyoxyalkylene polymer (A) and a reactive silicon group-containing polyoxyalkylene polymer (B) has a viscosity of 6.0 Pa·s or less at 23° C., and the number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (B) is smaller by 3,000 or more than the number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (A).

[2]. The terminal portion of the reactive silicon group-containing polyoxyalkylene polymer (A) is represented by the general formula (2):

(wherein R ¹ , X, and a are the same as defined above. R ² and R ⁴ each independently represent a divalent linking group having 1 to 6 carbon atoms which may contain a heteroatom. R ³ and R ⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. n is an integer from 1 to 10.)

[3]. The curable composition according to [1] or [2], wherein the reactive silicon group-containing polyoxyalkylene polymer (A) has a number average molecular weight of 12,000 to 25,000.

[4]. The curable composition according to any one of [1] to [3], wherein the number of reactive silicon groups per terminal structure of the reactive silicon group-containing polyoxyalkylene polymer (A) is 1.2 or more on average.

[5]. The curable composition according to any one of [1] to [4], wherein the reactive silicon group-containing polyoxyalkylene polymer (A) has a linear polymer skeleton.

[6]. The curable composition according to any one of [1] to [5], wherein the number of reactive silicon groups contained in one molecule of the reactive silicon group-containing polyoxyalkylene polymer (B) is 1.4 to 3.0 on average.

[7]. The curable composition according to any one of [1] to [6], wherein the reactive silicon group-containing polyoxyalkylene polymer (B) has a branched polymer skeleton.

[8]. The curable composition according to any one of [1] to [7], wherein the reactive silicon group-containing polyoxyalkylene polymer (B) has a number average molecular weight of 3,000 to 6,000.

[9]. The curable composition according to any one of [1] to [8], wherein the ratio (A)/(B) of the reactive silicon group-containing polyoxyalkylene polymer (A) to the reactive silicon group-containing polyoxyalkylene polymer (B) is 30/70 to 95/5.

[10]. The curable composition according to any one of [1] to [9] further comprises a reactive silicon group-containing polyoxyalkylene polymer (H) in which the terminal structure has a reactive silicon group and a terminal olefin group and/or an internal olefin group, the total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structure is 1.0 or less on average per terminal structure, and the number of reactive silicon groups contained in one molecule is less than 1.1 on average.

[11]. A cured product obtained by curing the curable composition according to any one of [1] to [10].

[12]. An adhesive composition comprising the curable composition according to any one of [1] to [10].

[13]. A sealant composition comprising the curable composition according to any one of [1] to [10].

The present invention provides a curable composition that has low viscosity, good workability, and produces a cured product with high strength (high tensile strength) after curing.

One embodiment of the present invention will be described below, but the present invention is not limited thereto. In addition, unless otherwise specified in this specification, "A to B" indicating a numerical range means "A or more (including A and larger than A) and B or less (including B and smaller than B)."

The present invention relates to a compound represented by general formula (1):
-Si(R ¹ ) _3-a (X) _a (1)
(In the formula, each R ¹ independently 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. a is 1, 2, or 3.)
a reactive silicon group-containing polyoxyalkylene polymer (A) having a reactive silicon group represented by the formula:
a reactive silicon group-containing polyoxyalkylene polymer (B) having a reactive silicon group represented by general formula (1), the reactive silicon group being represented by general formula (1), the terminal structure having a reactive silicon group and a terminal olefin group and/or an internal olefin group, the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure being 1.0 or less on average per terminal structure, and the number of reactive silicon groups contained in one molecule being 1.1 to 4.0 on average;
A curable composition comprising:
The present invention relates to a curable composition in which a blend of a reactive silicon group-containing polyoxyalkylene polymer (A) and a reactive silicon group-containing polyoxyalkylene polymer (B) has a viscosity of 6.0 Pa·s or less at 23° C., and the number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (B) is smaller by 3,000 or more than the number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (A).

<<Reactive Silicon Group-Containing Polyoxyalkylene Polymer (A)>>
The reactive silicon group-containing polyoxyalkylene polymer (A) (also referred to as polymer (A)) is represented by the general formula (1):
-Si(R ¹ ) _3-a (X) _a (1)
(In the formula, each R ¹ independently 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. a is 1, 2, or 3.)
The reactive silicon group-containing polyoxyalkylene polymer (A) has a reactive silicon group represented by the formula: wherein the terminal structure has a reactive silicon group, a terminal olefin group and/or an internal olefin group, and the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure is more than 1.0 on average per terminal structure. By having the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure be more than 1.0 on average per terminal structure, a curable composition can be obtained that gives a cured product with high strength (high tensile strength) and high tensile shear strength.

The reactive silicon group-containing polyoxyalkylene polymer (A) has a polymer skeleton composed of repeating oxyalkylene units and a terminal structure bonded to the end of the polymer skeleton. The polymer skeleton of the reactive silicon group-containing polyoxyalkylene polymer (A) may be linear or branched, but a linear polymer skeleton is preferred in that the cured product of the curable composition has high elongation and tear strength. A linear polymer skeleton can be formed by using an initiator having two hydroxyl groups per molecule in the polymerization method for forming the polymer skeleton, and a branched polymer skeleton can be formed by using an initiator having three or more hydroxyl groups per molecule.

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 silicon group of the reactive silicon group-containing polyoxyalkylene polymer (A) is preferably contained in the terminal structure. In this case, each terminal structure may contain a reactive silicon group, or a terminal structure containing a reactive silicon group and a terminal structure not containing a reactive silicon group may coexist.

The term "terminal structure has a reactive silicon group and a terminal olefin group and/or an internal olefin group" does not mean that all of the individual terminal structures contained in the polymer have a reactive silicon group and a terminal olefin group and/or an internal olefin group, but means that the terminal structure in the entire polymer (A) containing a large number of polymer molecules may have a reactive silicon group and a terminal olefin group and/or an internal olefin group. In other words, the terminal structure in a certain molecule contained in the polymer (A) may have only a reactive silicon group and no terminal olefin group or no internal olefin group, or may have either a terminal olefin group or an internal olefin group or both, but no reactive silicon group.

The reactive silicon group-containing polyoxyalkylene polymer (A) has a total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures that is greater than 1.0 on average per terminal structure, preferably 1.2 or more, and more preferably 1.4 or more. The upper limit of the total number of the terminal structures in the polymer (A) is not particularly limited, but is preferably 4.0 or less, more preferably 3.0 or less, and particularly preferably 2.0 or less.

The number of reactive silicon groups per terminal structure of the reactive silicon group-containing polyoxyalkylene polymer (A) is preferably 0.5 or more on average, more preferably 0.8 or more, even more preferably 1.2 or more, and most preferably 1.4 or more. The upper limit of the number of reactive silicon groups per terminal structure of the polymer (A) is not particularly limited, but is preferably 4.0 or less, more preferably 3.0 or less, and particularly preferably 2.0 or less.

The number of reactive silicon groups contained in one molecule of the reactive silicon group-containing polyoxyalkylene polymer (A) is preferably 0.5 to 8.0 on average, more preferably 1.0 to 6.0, and even more preferably 1.5 to 5.0.

<Reactive silicon group>
The reactive silicon group-containing polyoxyalkylene polymer (A) is represented by the general formula (1):
-Si(R ¹ ) _3-a (X) _a (1)
(In the formula, each R ¹ independently 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. a is 1, 2, or 3.)
The compound has a reactive silicon group represented by the formula:

^R1 is a hydrocarbon group having 1 to 20 carbon atoms. The number of carbon atoms in the hydrocarbon group represented by ^R1 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 a 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.

When R ¹ is a hydrocarbon group substituted with a hetero-containing group, the total number of carbon atoms and heteroatoms in R ¹ is preferably 2 to 30, more preferably 2 to 18, even more preferably 2 to 10, and particularly preferably 2 to 6.

Specific examples of the hydrocarbon group having 1 to 20 carbon atoms as R ¹ include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethyl-n-hexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-octadecyl, n-nonadecyl, and n-icosyl; vinyl. alkenyl 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 above-mentioned hetero-containing groups are also preferred as ^R1 .

Suitable examples of R ¹ 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. ^{R 1} 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 groups, halogens, alkoxy groups, acyloxy groups, ketoximate groups, amino groups, amide groups, acid amide groups, aminooxy groups, mercapto groups, and alkenyloxy groups. Among these, alkoxy groups such as methoxy and ethoxy groups are more preferred because they are mildly hydrolyzable and easy to handle, with methoxy and ethoxy groups being particularly preferred.

a is 1, 2, or 3. a is preferably 2 or 3.

Specific examples of reactive silicon groups include, but are not limited to, trimethoxysilyl, triethoxysilyl, tris(2-propenyloxy)silyl, triacetoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethoxyethylsilyl, (chloromethyl)dimethoxysilyl, (chloromethyl)diethoxysilyl, (methoxymethyl)dimethoxysilyl, (methoxymethyl)diethoxysilyl, (N,N-diethylaminomethyl)dimethoxysilyl, and (N,N-diethylaminomethyl)diethoxysilyl. Among these, dimethoxymethylsilyl, trimethoxysilyl, triethoxysilyl, and (methoxymethyl)dimethoxysilyl are preferred because they give cured products with good mechanical properties. From the viewpoint of activity, trimethoxysilyl group, (chloromethyl)dimethoxysilyl group, and (methoxymethyl)dimethoxysilyl group are more preferred, and trimethoxysilyl group and (methoxymethyl)dimethoxysilyl group are particularly preferred. From the viewpoint of stability, dimethoxymethylsilyl group and triethoxysilyl group are more preferred, and dimethoxymethylsilyl group is particularly preferred.

<Terminal structure>
In the reactive silicon group-containing polyoxyalkylene polymer (A), the terminal structure having the reactive silicon group is not particularly limited, but may contain a terminal olefin group or an internal olefin group in addition to the reactive silicon group. The terminal olefin group and the internal olefin group are groups contained in the raw materials for producing the reactive silicon group-containing polyoxyalkylene polymer (A) or groups generated during the production.

A typical example of a terminal structure is the terminal moiety (terminal structure) represented by the following general formula (2).

In the formula, R ¹ , X, and a are the same as above. R ² and R ⁴ each independently represent a divalent linking group having 1 to 6 carbon atoms which may contain a heteroatom. ^{R 3} and R ⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. n is an integer from 1 to 10.

^R2 is a divalent linking group having 1 to 6 carbon atoms which may contain a heteroatom, and the linking group is preferably a hydrocarbon group or a hydrocarbon group containing an oxygen atom. The number of carbon atoms is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to _2. Preferably, it is _{CH2OCH2 , CH2O} , or _CH2 , and more preferably _CH2OCH2 .

^R3 is preferably hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, more preferably hydrogen or a hydrocarbon group having 1 to 3 carbon atoms, and even more preferably hydrogen or a hydrocarbon group having 1 to 2 carbon atoms. Particularly preferred are a hydrogen atom and a methyl group, and most preferably a hydrogen atom.

^R4 is a divalent linking group having 1 to 6 carbon atoms which may contain a heteroatom, and the linking group is preferably a hydrocarbon group or a hydrocarbon group containing a heteroatom, and more preferably a hydrocarbon group having 1 to 2 carbon atoms. The heteroatom is preferably an oxygen atom and/or a nitrogen atom. The linking group is preferably a methylene group, an ethylene group, a propylene group, a butylene group, or C(O)NH ₂ CH ₂ , and particularly preferably a methylene group.

^R5 is preferably hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, more preferably hydrogen or a hydrocarbon group having 1 to 3 carbon atoms, and even more preferably hydrogen or a hydrocarbon group having 1 to 2 carbon atoms. Particularly preferred are a hydrogen atom and a methyl group, and most preferably a hydrogen atom.

The terminal structure represented by general formula (2) represents one terminal structure bonded to one end of the polymer skeleton. Although two or more reactive silicon groups are shown in formula (2), formula (2) does not indicate two or more ends, but indicates that two or more reactive silicon groups are present in one terminal structure. Furthermore, except for the oxygen at the left end, formula (2) does not include a polymer skeleton composed of repeating units such as oxyalkylene units. In other words, the n structures in parentheses present in formula (2) do not correspond to repeating units in the polymer skeleton.

<Main chain structure>
The main chain structure of the reactive silicon group-containing polyoxyalkylene polymer (A) may be either linear or branched, but is preferably linear.

The main chain of the reactive silicon group-containing polyoxyalkylene polymer (A) is a polymer having a repeating unit represented by -R ⁶ -O- (wherein R ⁶ is a linear or branched alkylene group having 1 to 14 carbon atoms), and R ⁶ is more preferably a linear or branched alkylene group having 2 to 4 carbon atoms. Specific examples of the repeating unit represented by -R ⁶ -O- include -CH ₂ O-, -CH ₂ CH ₂ O-, -CH ₂ CH(CH ₃ )O-, -CH ₂ C(CH ₃ )(CH ₃ )O- and -CH ₂ CH ₂ CH ₂ CH ₂ O-, and the like, with -CH ₂ CH ₂ O- and -CH ₂ CH(CH ₃ )O- being preferred, and -CH ₂ CH(CH ₃ )O- being more preferred.

The number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (A) is not particularly limited, but is preferably 5,000 to 100,000, more preferably 10,000 to 40,000, particularly preferably 12,000 to 25,000, and most preferably 13,000 to 20,000, as calculated based on polystyrene standards in GPC. If the number average molecular weight is within the above range, the amount of reactive silicon groups introduced is appropriate, making it easy to obtain a reactive silicon group-containing polyoxyalkylene polymer (A) with high strength while keeping production costs within an appropriate range.

Furthermore, it is preferable to use a reactive silicon group-containing polyoxyalkylene polymer (A) having a number average molecular weight of 12,000 to 25,000 and an average of 1.2 or more reactive silicon groups per terminal structure, since the resulting cured product has high tear strength.

The molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (A) can also 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 the reactive silicon 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 account the structure of the polymer (degree of branching determined by the polymerization initiator used). The end group-equivalent molecular weight of the 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 reactive silicon group-containing polymer into the end group-equivalent molecular weight.

The molecular weight distribution (Mw/Mn) of the reactive silicon group-containing polyoxyalkylene polymer (A) is not particularly limited, but is preferably narrow. Specifically, it is preferably 1.6 or less, more preferably 1.4 or less, even more preferably 1.3 or less, and particularly preferably 1.2 or less. The molecular weight distribution of the reactive silicon group-containing 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 silicon group-containing polyoxyalkylene polymer (A)>
Next, a method for producing the reactive silicon group-containing polyoxyalkylene polymer (A) will be described. The reactive silicon group-containing polyoxyalkylene polymer (A) is preferably produced by a method in which an olefin group is introduced into a hydroxyl-terminated polyoxyalkylene polymer (C) by utilizing the reactivity of the hydroxyl group, and then a reactive silicon group-containing compound having reactivity with the olefin group is reacted to introduce the reactive silicon 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 hydroxyl-terminated polyoxyalkylene polymer (C). 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, organic compounds having one or more hydroxyl groups, such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, low molecular weight polyoxypropylene glycol, low molecular weight polyoxypropylene triol, allyl alcohol, low molecular weight polyoxypropylene monoallyl ether, and low molecular weight polyoxypropylene monoalkyl ether.

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 an olefin group into the hydroxyl-terminated polyoxyalkylene polymer (C), it is preferable to first react an alkali metal salt with the hydroxyl-terminated polyoxyalkylene polymer (C) to convert the terminal hydroxyl groups into metaloxy groups. Also, a composite metal cyanide complex catalyst can be used instead of the alkali metal salt. In this manner, the metaloxy-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, cesium alkoxide, etc. In view of ease of handling and solubility, sodium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium hydroxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide are preferred, and sodium methoxide and sodium tert-butoxide are more preferred. In view of availability, sodium methoxide is particularly preferred, and in view of reactivity, sodium tert-butoxide is particularly preferred. The alkali metal salt may be dissolved in a solvent and then subjected to the reaction.

The amount of the alkali metal salt used is not particularly limited, but the molar ratio to the hydroxyl groups of the hydroxyl-terminated polyoxyalkylene polymer (C) is preferably 0.5 or more, more preferably 0.6 or more, even more preferably 0.7 or more, and even more preferably 0.8 or more. The molar ratio is preferably 1.2 or less, and more preferably 1.1 or less.

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

(Reaction with electrophile (E))
The metaloxy group-terminated polyoxyalkylene polymer (D) obtained as described above is reacted with an electrophilic agent (E) having an olefin group to convert the metaloxy group into a structure containing an olefin group, thereby forming a polyoxyalkylene polymer (F) having an olefin group in the terminal structure.

The electrophile (E) having an olefin group 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 an olefin group into the polyoxyalkylene polymer, but examples of the electrophile include an epoxy compound (E1) having an olefin group and an organic halide (E2) having an olefin group.

The epoxy compound (E1) having an olefin group, which is one embodiment of the electrophile (E), can react with the metaloxy group through a ring-opening addition reaction of the epoxy group to form an ether bond, thereby introducing a structure containing an olefin group and a hydroxyl group as the terminal structure of the polyoxyalkylene polymer. In the ring-opening addition reaction, one or more epoxy compounds (E1) can be added to one metaloxy group by adjusting the amount of epoxy compound (E1) used relative to the metaloxy group and the reaction conditions.

The epoxy compound (E1) having an olefin group is, but is not limited to, the following general formula (3):

In the formula, ^R2 and ^R3 are the same groups as ^R2 and ^R3 described above for general formula (2), respectively.

Specific examples of the epoxy compound (E1) having an olefin group are not particularly limited, but allyl glycidyl ether, methallyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, and butadiene monoxide are preferred in terms of reaction activity, with allyl glycidyl ether being particularly preferred.

The amount of epoxy compound (E1) having an olefin group added can be any amount taking into consideration the amount of olefin group introduced into the polymer and the reactivity. In particular, the molar ratio of epoxy compound (E1) to hydroxyl groups in polyoxyalkylene polymer (C) is preferably 0.2 or more, more preferably 0.5 or more. The molar ratio is preferably 5.0 or less, more preferably 2.0 or less.

The reaction temperature when the metaloxy group-terminated polyoxyalkylene polymer (D) is subjected to a ring-opening addition reaction with the epoxy compound (E1) having an olefin group is preferably from 60°C to 160°C, more preferably from 110°C to 150°C.

As described above, when an epoxy compound (E1) having an olefin group is reacted with a 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 (E1), it is also possible to continuously react with an organic halide (E2) having an olefin group. This method is preferable because it can further increase the amount of olefin groups and reactive silicon groups introduced into the polymer.

The organic halide (E2) having an olefin group reacts with the metaloxy group through a halogen substitution reaction to form an ether bond, and can introduce a structure containing an olefin group as a terminal structure of the polyoxyalkylene polymer. The organic halide (E2) having an olefin group is, but is not limited to, a compound represented by the following general formula (4):
Z-R ⁴ -C(R ⁵ )=CH ₂ (4)
In the formula, ^R4 and ^R5 are the same groups as ^R4 and ^R5 described above for general formula (2), respectively. Z represents a halogen atom.

Specific examples of organic halides (E2) having an olefin group include, but are not limited to, vinyl chloride, allyl chloride, methallyl chloride, propargyl chloride, vinyl bromide, allyl bromide, methallyl bromide, propargyl bromide, vinyl iodide, allyl iodide, methallyl iodide, propargyl iodide, etc. Allyl chloride and methallyl chloride are preferred because of ease of handling.

The amount of organic halide (E2) having an olefin group to be added is not particularly limited, but the molar ratio of organic halide (E2) to the hydroxyl groups of the polyoxyalkylene polymer (C) is preferably 0.7 or more, more preferably 1.0 or more. The molar ratio is preferably 5.0 or less, more preferably 2.0 or less.

The temperature at which the metaloxy group-terminated polyoxyalkylene polymer (D) is reacted with the organic halide (E2) having an olefin group is preferably from 50°C to 150°C, more preferably from 110°C to 140°C. The reaction time is preferably from 10 minutes to 5 hours, more preferably from 30 minutes to 3 hours.

When a reactive silicon group, as described below, is introduced into the polyoxyalkylene polymer (F) having an olefin group in the terminal structure obtained by the above-mentioned method of using the epoxy compound (E1) and the organic halide (E2) in combination, a terminal structure represented by the general formula (2) can be formed.

(Introduction of reactive silicon groups)
The polyoxyalkylene polymer (F) having an olefin group in the terminal structure obtained as above is subjected to a hydrosilylation reaction with a hydrosilane compound (G) having a reactive silicon group, thereby introducing a reactive silicon group into the polymer. This produces a polyoxyalkylene polymer (A) containing a reactive silicon group, the main chain of which is a polyoxyalkylene polymer. The hydrosilylation reaction has the advantages of being easily carried out, of being easy to adjust the amount of reactive silicon group introduced, and of having stable physical properties of the resulting polymer.

Specific examples of the hydrosilane compound (G) having a reactive silicon group include halosilanes such as trichlorosilane, dichloromethylsilane, chlorodimethylsilane, dichlorophenylsilane, (chloromethyl)dichlorosilane, (dichloromethyl)dichlorosilane, bis(chloromethyl)chlorosilane, (methoxymethyl)dichlorosilane, (dimethoxymethyl)dichlorosilane, and bis(methoxymethyl)chlorosilane; trimethoxysilane, triethoxysilane, dimethoxymethylsilane, diethoxymethylsilane, dimethoxyphenylsilane, and ethoxysilane. ethyldimethoxysilane, methoxydimethylsilane, ethoxydimethylsilane, (chloromethyl)methylmethoxysilane, (chloromethyl)dimethoxysilane, (chloromethyl)diethoxysilane, bis(chloromethyl)methoxysilane, (methoxymethyl)methylmethoxysilane, (methoxymethyl)dimethoxysilane, bis(methoxymethyl)methoxysilane, (methoxymethyl)diethoxysilane, (ethoxymethyl)diethoxysilane, (3,3,3-trifluoropropyl)dimethoxysilane, (N,N-diethylaminomethyl)dimethoxysilane silane, (N,N-diethylaminomethyl)diethoxysilane, [(chloromethyl)dimethoxysilyloxy]dimethylsilane, [(chloromethyl)diethoxysilyloxy]dimethylsilane, [(methoxymethyl)dimethoxysilyloxy]dimethylsilane, [(methoxymethyl)diemethoxysilyloxy]dimethylsilane, [(diethylaminomethyl)dimethoxysilyloxy]dimethylsilane, [(3,3,3-trifluoropropyl)dimethoxysilyloxy]dimethylsilane, 1-[1-(trimethoxysilyl)ethyl]-1,1,3,3- Examples of such alkoxysilanes include tetramethyldisiloxane and 1-[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane; acyloxysilanes such as diacetoxymethylsilane and diacetoxyphenylsilane; ketoximate silanes such as bis(dimethylketoximate)methylsilane and bis(cyclohexylketoximate)methylsilane; and isopropenyloxysilanes such as triisopropenyloxysilane, (chloromethyl)diisopropenyloxysilane, and (methoxymethyl)diisopropenyloxysilane.

The amount of the hydrosilane compound (G) having a reactive silicon group used may be appropriately set in consideration of the amount of olefin groups contained in the polyoxyalkylene polymer (F). Specifically, the molar ratio of the hydrosilane compound (G) to the olefin groups contained in the polyoxyalkylene polymer (F) is preferably 0.05 to 10 in terms of reactivity, and more preferably 0.3 to 3 in terms of reactivity. In order to increase the modulus value of the cured product of the reactive silicon group-containing polymer (B) obtained, the molar ratio is more preferably 0.5 or more, and particularly preferably 0.7 or more. On the other hand, from the viewpoint of economy, the molar ratio is more preferably 2.5 or less, and particularly preferably 2 or less.

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 carriers such as alumina, silica, and carbon black; chloroplatinic acid; chloroplatinic acid complexes composed of chloroplatinic acid and alcohols, aldehydes, ketones, and the like; 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 ], and the like. From the standpoint of reaction efficiency, platinum catalysts such as chloroplatinic acid and platinum vinylsiloxane complexes are preferred.

The temperature conditions for the hydrosilylation reaction are not particularly limited and can be set appropriately by a person skilled in the art, but in order to reduce the viscosity of the reaction system and improve reactivity, the reaction is preferably carried out under heated conditions, more preferably at 50°C to 150°C, and even more preferably at 70°C to 120°C. The reaction time may also be set appropriately, but it is preferable to adjust the reaction time along with the temperature conditions so that unintended condensation reactions between polymers do not proceed. Specifically, the reaction time is preferably 30 minutes or more and 5 hours or less, and more preferably 3 hours or less.

<<Reactive Silicon Group-Containing Polyoxyalkylene Polymer (B)>>
The reactive silicon group-containing polyoxyalkylene polymer (B) of the present invention (also referred to as polymer (B)) is a reactive silicon group-containing polyoxyalkylene polymer (B) having a reactive silicon group represented by general formula (1), in which the terminal structure has a reactive silicon group, and a terminal olefin group and/or an internal olefin group, the total number of the reactive silicon groups, terminal olefin groups and internal olefin groups in the terminal structure is on average 1.0 or less per terminal structure, and the number of reactive silicon groups contained in one molecule is 1.1 to 4.0 on average.

The reactive silicon group-containing polyoxyalkylene polymer (B) has a polymer skeleton composed of repeating oxyalkylene units and a terminal structure bonded to the end of the polymer skeleton. The polymer skeleton of the reactive silicon group-containing polyoxyalkylene polymer (B) may be linear or branched, but a branched polymer skeleton is preferred in that the strength of the cured product of the curable composition is high. A linear polymer skeleton can be formed by using an initiator having two hydroxyl groups per molecule in the polymerization method for forming the polymer skeleton, and a branched polymer skeleton can be formed by using an initiator having three or more hydroxyl groups per molecule.

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 silicon group of the reactive silicon group-containing polyoxyalkylene polymer (B) is preferably contained in the terminal structure. In this case, each terminal structure may contain a reactive silicon group, or a terminal structure containing a reactive silicon group and a terminal structure not containing a reactive silicon group may coexist.

The term "terminal structure has a reactive silicon group and a terminal olefin group and/or an internal olefin group" does not mean that all of the individual terminal structures contained in the polymer have a reactive silicon group and a terminal olefin group and/or an internal olefin group, but means that the terminal structure in the entire polymer (B) containing a large number of polymer molecules may have a reactive silicon group and a terminal olefin group and/or an internal olefin group. In other words, the terminal structure in a certain molecule contained in polymer (B) may have only a reactive silicon group and no terminal olefin group or no internal olefin group, or may have either a terminal olefin group or an internal olefin group or both, but no reactive silicon group.

In polymer (B), the total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures is, on average, 1.0 or less per terminal structure. In addition, the lower limit of the total number of the terminal structures in polymer (B) is not particularly limited, but is preferably 0.3 or more, and more preferably 0.5 or more.

The number of reactive silicon groups contained in one molecule of the reactive silicon group-containing polyoxyalkylene polymer (B) is, on average, 1.1 to 4.0. This improves the strength when blended with the reactive silicon group-containing polyoxyalkylene polymer (A). The number of reactive silicon groups is preferably 1.2 to 3.5, more preferably 1.4 to 3.0, even more preferably 1.7 to 3.0, and particularly preferably 2.0 to 3.0.

<Reactive silicon group>
The reactive silicon group of the reactive silicon group-containing polyoxyalkylene polymer (B) may be the same as the reactive silicon group described for the reactive silicon group-containing polyoxyalkylene polymer (A), but may be any of the following general formula (1-1):
-Si(R ⁷ ) _3-b (OR ⁸ ) _b (1-1)
(In the formula, R ⁷ is independently an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, or an N,N-dialkylaminoalkyl group represented by -R ⁹ N(R ¹⁰ ) ₂ , R ⁹ is a methylene group or an ethylene group, R ¹⁰ is a methyl group or an ethyl group, R ⁸ is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an acyl group having 2 to 6 carbon atoms, and b is 2 or 3.)
A group represented by the following formula is preferred.

Specific examples of the alkyl group having 1 to 6 carbon atoms as ^R7 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group, etc. Of these, a methyl group and an ethyl group are preferred.

Specific examples of the haloalkyl group having 1 to 6 carbon atoms as ^R7 include a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a 2-chloroethyl group, and a 2-bromoethyl group, etc. Among these, a chloromethyl group and a bromomethyl group are preferred, and a chloromethyl group is more preferred.

Specific examples of the alkoxyalkyl group having 2 to 6 carbon atoms as ^R7 include a methoxymethyl group, a 2-methoxyethyl group, a 1-methoxyethyl group, an ethoxymethyl group, a 2-ethoxyethyl group, an n-propyloxymethyl group, and a 2-n-propyloxyethyl group, etc. Of these, a methoxymethyl group, a 2-methoxyethyl group, and an ethoxymethyl group are preferred, and a methoxymethyl group is more preferred.

Specific examples of the N,N-dialkylaminoalkyl group represented by -R ⁹ N(R ¹⁰ ) ₂ as R ⁷ include an N,N-dimethylaminomethyl group, an N,N-diethylaminomethyl group, a 2-N,N-dimethylaminoethyl group, and a 2-N,N-diethylaminoethyl group. Of these, an N,N-dimethylaminomethyl group and an N,N-diethylaminomethyl group are preferred, and an N,N-diethylaminomethyl group is more preferred.

Specific examples of the alkyl group having 1 to 6 carbon atoms as ^R8 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group, etc. Of these, a methyl group and an ethyl group are preferred.

Specific examples of the alkenyl group having 2 to 6 carbon atoms as ^R8 include a vinyl group, a 2-propenyl group, a 3-butenyl group, and a 4-pentenyl group, etc. Of these, a vinyl group and a 2-propenyl group are preferred.

Specific examples of the acyl group having 2 to 6 carbon atoms as R ⁸ include an acetyl group, a propionyl group, a butanoyl group, and a pentanoyl group. Of these, an acetyl group is preferred.

Specific examples of reactive silicon groups include, but are not limited to, trimethoxysilyl, triethoxysilyl, tris(2-propenyloxy)silyl, triacetoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethoxyethylsilyl, (chloromethyl)dimethoxysilyl, (chloromethyl)diethoxysilyl, (methoxymethyl)dimethoxysilyl, (methoxymethyl)diethoxysilyl, (N,N-diethylaminomethyl)dimethoxysilyl, and (N,N-diethylaminomethyl)diethoxysilyl. Among these, dimethoxymethylsilyl, trimethoxysilyl, triethoxysilyl, and (methoxymethyl)dimethoxysilyl are preferred because they give cured products with good mechanical properties. From the viewpoint of activity, trimethoxysilyl group, (chloromethyl)dimethoxysilyl group, and (methoxymethyl)dimethoxysilyl group are more preferred, and trimethoxysilyl group and (methoxymethyl)dimethoxysilyl group are particularly preferred. From the viewpoint of stability, dimethoxymethylsilyl group and triethoxysilyl group are more preferred, and dimethoxymethylsilyl group is particularly preferred.

<Terminal structure>
In the reactive silicon group-containing polyoxyalkylene polymer (B), the terminal structure having a reactive silicon group is not particularly limited, but may contain a terminal olefin group or an internal olefin group in addition to the reactive silicon group. The terminal olefin group and the internal olefin group are groups contained in the raw materials for producing the reactive silicon group-containing polyoxyalkylene polymer (B) or groups generated during the production.

<Main chain structure>
The main chain structure of the reactive silicon group-containing polyoxyalkylene polymer (B) may be the same as that described for the polymer (A).

The number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (B) is at least 3,000 smaller than the number average molecular weight of the polymer (A). It is preferably at least 5,000 smaller, more preferably at least 7,000 smaller, and even more preferably at least 9,000 smaller. This results in a curable composition that, when blended with the polymer (A), produces a cured product with low viscosity and high strength (high tensile strength).

The number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (B) is preferably 1,000 to 12,000, more preferably 2,000 to 9,000, and even more preferably 3,000 to 6,000, as calculated based on polystyrene standards in GPC. If the number average molecular weight is less than 1,000, the amount of reactive silicon groups introduced will be large, which may be inconvenient in terms of production costs, and if it exceeds 12,000, the viscosity will be high, which tends to be inconvenient in terms of workability. The number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (B) can be determined in the same manner as for the polymer (A).

The molecular weight distribution (Mw/Mn) of the reactive silicon group-containing polyoxyalkylene polymer (B) is not particularly limited, but is preferably narrow. Specifically, it is preferably 1.6 or less, more preferably 1.4 or less, even more preferably 1.3 or less, and particularly preferably 1.2 or less. The molecular weight distribution of the reactive silicon group-containing polyoxyalkylene polymer (B) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

<Method for producing reactive silicon group-containing polyoxyalkylene polymer (B)>
Next, a method for producing the reactive silicon group-containing polyoxyalkylene polymer (B) will be described.

The main chain structure of the reactive silicon group-containing polyoxyalkylene polymer (B) is preferably obtained by: (i) obtaining a hydroxyl-terminated polyoxyalkylene polymer (C) by polymerizing an epoxy compound with an initiator having a hydroxyl group using a composite metal cyanide complex catalyst such as zinc hexacyanocobaltate glyme complex; (ii) converting the hydroxyl groups of the obtained hydroxyl-terminated polyoxyalkylene polymer to carbon-carbon unsaturated groups and then adding a silane compound by hydrosilylation reaction; or (ii) reacting the obtained hydroxyl-terminated polyoxyalkylene polymer (C) with a compound having both a group reactive with a hydroxyl group and a reactive silicon group. Of the above two methods, method (i) is more preferred because the reaction is simple, the amount of reactive silicon group introduced is easily adjusted, and the physical properties of the obtained reactive silicon group-containing polymer are stable.

Examples of initiators having hydroxyl groups include those having two or more hydroxyl groups, such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, low molecular weight polyoxypropylene glycol, and polyoxypropylenetriol.

Epoxy compounds include alkylene oxides such as ethylene oxide and propylene oxide, and glycidyl ethers such as methyl glycidyl ether and allyl glycidyl ether. Of these, propylene oxide is preferred.

Examples of the carbon-carbon unsaturated group used in method (i) include vinyl groups, allyl groups, and methallyl groups. Of these, allyl groups are preferred.

As a method for converting the hydroxyl groups in (i) to carbon-carbon unsaturated groups, it is preferable to use a method in which an alkali metal salt is reacted with a polymer containing hydroxyl groups at its ends, and then a halogenated hydrocarbon compound having a carbon-carbon unsaturated bond is reacted therewith.

Halogenated hydrocarbon compounds used in method (i) include vinyl chloride, allyl chloride, methallyl chloride, vinyl bromide, allyl bromide, methallyl bromide, vinyl iodide, allyl iodide, and methallyl iodide.

Examples of hydrosilane compounds used in method (i) include halogenated silanes such as trichlorosilane, dichloromethylsilane, chlorodimethylsilane, and dichlorophenylsilane; alkoxysilanes such as trimethoxysilane, triethoxysilane, dimethoxymethylsilane, diethoxymethylsilane, dimethoxyphenylsilane, ethyldimethoxysilane, methoxydimethylsilane, and ethoxydimethylsilane; acyloxysilanes such as diacetoxymethylsilane and diacetoxyphenylsilane; ketoximate silanes such as bis(dimethylketoximate)methylsilane and bis(cyclohexylketoximate)methylsilane; and isopropenyloxysilanes (deacetone type) such as triisopropenyloxysilane.

The hydrosilylation reaction used in method (i) can be accelerated by the use of various catalysts, including known catalysts such as complexes of cobalt, nickel, iridium, platinum, palladium, rhodium, ruthenium, and the like. For example, platinum supported on a carrier such as alumina, silica, or carbon black, chloroplatinic acid, chloroplatinic acid complexes consisting of chloroplatinic acid and alcohols, aldehydes, ketones, or the like, platinum-olefin complexes [e.g., Pt( _CH2 = _CH2 ) ₂ ( _PPh3 ), Pt( _CH2 = _CH2 ) _2Cl2 ], platinum- _{vinylsiloxane} complexes [Pt{(vinyl) _Me2SiOSiMe2 (vinyl)}, Pt{Me(vinyl)SiO} ₄ ], platinum-phosphine complexes [Ph( _PPh3 ) ₄ , Pt _{( PBu3} ) ₄ ], platinum-phosphite complexes [Pt{P(OPh) ₃ } ₄ ], and the like can be used.

Compounds having both a group reactive with a hydroxyl group and a reactive silicon group that can be used in method (ii) include isocyanate silanes such as 3-isocyanate propyl trimethoxy silane, 3-isocyanate propyl dimethoxy methyl silane, 3-isocyanate propyl triethoxy silane, isocyanate methyl trimethoxy silane, isocyanate methyl triethoxy silane, and isocyanate methyl dimethoxy methyl silane; mercapto silanes such as 3-mercapto propyl trimethoxy silane and 3-mercapto propyl dimethoxy methyl silane; and epoxy silanes such as 3-glycidoxy propyl trimethoxy silane and 3-glycidoxy propyl dimethoxy methyl silane.

<Blend of reactive silicon group-containing polymer (A) and reactive silicon group-containing polymer (B)>
The weight ratio of the reactive silicon group-containing polyoxyalkylene polymer (A) to the reactive silicon group-containing polyoxyalkylene polymer (B) is not particularly limited, but (A)/(B) is preferably 30/70 to 95/5, more preferably 50/50 to 95/5, even more preferably 60/40 to 95/5, and most preferably 60/40 to 90/10. If the weight ratio of the reactive silicon group-containing polyoxyalkylene polymer (B) is less than 5%, it is not preferred because the effect of improving workability due to the reduced viscosity is difficult to achieve, and if it exceeds 70%, it is not preferred because the strength is significantly reduced.

The viscosity of the blend of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B) at 23°C is 6.0 Pa·s or less. This reduces the viscosity of the resulting curable composition, improving workability when applying the curable composition. The viscosity is preferably 5.0 Pa·s or less. The lower limit of the viscosity is preferably 1.0 Pa·s or more, and more preferably 2.0 Pa·s or more.

As a combination of reactive silicon group-containing polyoxyalkylene polymer (A) and reactive silicon group-containing polyoxyalkylene polymer (B), a reactive silicon group-containing polyoxyalkylene polymer (A) having a number average molecular weight of 12,000 to 25,000 and an average of 1.2 or more reactive silicon groups per terminal structure and a branched reactive silicon group-containing polyoxyalkylene polymer (B) having a number average molecular weight of 3,000 to 6,000 is preferred because the curable composition has a low viscosity, yet the resulting cured product has high tensile strength, high shear strength, high tear strength and high elongation.

<<Reactive Silicon Group-Containing Polyoxyalkylene Polymer (H)>>
The curable composition of the present invention may further contain a reactive silicon group-containing polyoxyalkylene polymer (H) (also referred to as polymer (H)) having a terminal structure having a reactive silicon group, a terminal olefin group and/or an internal olefin group, wherein the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure is on average 1.0 or less per terminal structure and the number of reactive silicon groups contained in one molecule is on average less than 1.1.

The term "terminal structure has a reactive silicon group and a terminal olefin group and/or an internal olefin group" does not mean that all of the individual terminal structures contained in the polymer have a reactive silicon group and a terminal olefin group and/or an internal olefin group, but means that the terminal structure in the entire polymer (H) containing a large number of polymer molecules may have a reactive silicon group and a terminal olefin group and/or an internal olefin group. In other words, the terminal structure in one molecule contained in the polymer (H) may have only a reactive silicon group and no terminal olefin group or no internal olefin group, or may have either a terminal olefin group or an internal olefin group or both, but no reactive silicon group.

In the reactive silicon group-containing polyoxyalkylene polymer (H), the total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures is, on average, 1.0 or less per terminal structure, preferably 0.8 or less, and more preferably 0.5 or less. In addition, the upper limit of the total number of the terminal structures of the polymer (H) is not particularly limited, but is preferably 0.1 or more, and more preferably 0.3 or more.

The number of reactive silicon groups contained in one molecule of the reactive silicon group-containing polyoxyalkylene polymer (H) is on average less than 1.1, but is preferably 1.0 or less. The lower limit of the average number of reactive silicon groups is preferably 0.3 or more, and more preferably 0.5 or more.

<Reactive silicon group>
The reactive silicon group-containing polyoxyalkylene polymer (H) preferably has a reactive silicon group represented by the above general formula (1).

The reactive silicon groups can be the same as those in polymer (A) and polymer (B).

When using a linear reactive silicon group-containing polyoxyalkylene polymer (H), it is preferable to have a reactive silicon group on only one side of each molecule, as this can prevent changes in physical properties before addition.

<Terminal structure>
In the reactive silicon group-containing polyoxyalkylene polymer (H), the terminal structure having the reactive silicon group is not particularly limited, but may contain a terminal olefin group or an internal olefin group in addition to the reactive silicon group. The terminal olefin group and the internal olefin group are groups contained in the raw materials for producing the reactive silicon group-containing polyoxyalkylene polymer (H) or groups generated during the production.

<Main chain structure>
The main chain structure of the reactive silicon group-containing polyoxyalkylene polymer (H) can be the same as that of the polymer (A) or (B), and may be linear or branched, but is preferably linear.

<Method for producing reactive silicon group-containing polyoxyalkylene polymer (H)>
Next, a method for producing the reactive silicon group-containing polyoxyalkylene polymer (H) will be described.

The reactive silicon group-containing polyoxyalkylene polymer (H) can be obtained in the same manner as the polymer (B), but the following method is preferred.

(i) A method of obtaining a hydroxyl-terminated polyoxyalkylene polymer (C) by polymerizing an epoxy compound with an initiator having two or more hydroxyl groups using a composite metal cyanide complex catalyst such as zinc hexacyanocobaltate glyme complex, converting the hydroxyl groups of the obtained hydroxyl-terminated polyoxyalkylene polymer to carbon-carbon unsaturated groups, and then adding a silane compound by hydrosilylation reaction so that the number of reactive silicon groups in one molecule is less than 1.1 on average. (ii) A method of obtaining a hydroxyl-terminated polyoxyalkylene polymer (C) by polymerizing an epoxy compound with an initiator having one hydroxyl group using a composite metal cyanide complex catalyst such as zinc hexacyanocobaltate glyme complex, converting the hydroxyl groups of the obtained hydroxyl-terminated polyoxyalkylene polymer to carbon-carbon unsaturated groups, and then adding a silane compound by hydrosilylation reaction.

Method (ii) is preferred because it has less effect on physical properties after addition.

<Amount of Polymer (H) Added>
The amount of the reactive silicon group-containing polyoxyalkylene polymer (H) added is not particularly limited, but is preferably 1 to 50 parts by weight, more preferably 5 to 30 parts by weight, per 100 parts by weight of the total of the polymer (A) and the polymer (B).

<<Other additives>>
In addition to the reactive silicon group-containing polyoxyalkylene polymer (A), the reactive silicon group-containing polyoxyalkylene polymer (B), and optionally the reactive silicon group-containing polyoxyalkylene polymer (H), the composition of the present invention may contain additives such as silanol condensation catalysts, fillers, adhesion promoters, plasticizers, sagging inhibitors, antioxidants, light stabilizers, ultraviolet absorbers, physical property adjusters, tackifier resins, compounds containing epoxy groups, photocurable substances, oxygen curable substances, epoxy resins, and other resins. In addition, various additives may be added to the curable composition of the present invention as necessary for the purpose of adjusting the various physical properties of the curable composition or the cured product. Examples of such additives include, for example, surface improvers, foaming agents, curability adjusters, flame retardants, silicates, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, and fungicides.

<Silanol condensation catalyst>
In the present invention, a silanol condensation catalyst may be used for the purpose of promoting the condensation reaction of the reactive silicon groups in the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B) and chain-extending or crosslinking the polymer.

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

Specific examples of organotin compounds include dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin bis(butyl maleate), dibutyltin diacetate, dibutyltin oxide, dibutyltin bis(acetylacetonate), dioctyltin bis(acetylacetonate), dioctyltin dilaurate, dioctyltin distearate, dioctyltin diacetate, dioctyltin oxide, reaction products of dibutyltin oxide with silicate compounds, reaction products of dioctyltin oxide with silicate compounds, and reaction products of dibutyltin oxide with phthalic acid esters.

Specific examples of metal carboxylates include tin carboxylate, bismuth carboxylate, titanium carboxylate, zirconium carboxylate, iron carboxylate, potassium carboxylate, and calcium carboxylate. The carboxylate group can be a combination of the following carboxylic acids with various metals.

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

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

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

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

Two or more different silanol condensation catalysts may be used in combination.

The amount of the silanol condensation catalyst used is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, and particularly preferably 0.01 to 10 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Filler>
The composition of the present invention may contain various fillers, such as ground calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, clay, talc, titanium oxide, fumed silica, precipitated silica, crystalline silica, fused silica, anhydrous silicic acid, hydrous silicic acid, carbon black, ferric oxide, fine aluminum powder, zinc oxide, activated zinc oxide, PVC powder, PMMA powder, glass fiber and filament.

The amount of filler used is preferably 1 to 300 parts by weight, and more preferably 10 to 250 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

Organic balloons or inorganic balloons may be added for the purpose of reducing the weight (lowering the specific gravity) of the composition. The balloons are spherical fillers that are hollow inside, and examples of the materials for the balloons include inorganic materials such as glass, shirasu, and silica, and organic materials such as phenol resin, urea resin, polystyrene, and saran. The amount of the balloons used is preferably 0.1 to 100 parts by weight, particularly preferably 1 to 20 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Adhesion promoter>
An adhesion promoter may be added to the composition of the present invention.

As an adhesion promoter, a silane coupling agent or a condensation reaction product of a silane coupling agent can be added.

Specific examples of silane coupling agents include amino group-containing silanes such as 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, N-β-aminoethyl-3-aminopropyltrimethoxysilane, N-β-aminoethyl-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and (2-aminoethyl)aminomethyltrimethoxysilane; 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, and 3- Examples of such silanes include isocyanate group-containing silanes such as isocyanate propyl methyl dimethoxy silane, isocyanate methyl trimethoxy silane, and isocyanate methyl dimethoxy methyl silane; mercapto group-containing silanes such as 3-mercapto propyl trimethoxy silane, 3-mercapto propyl triethoxy silane, and 3-mercapto propyl methyl dimethoxy silane; and epoxy group-containing silanes such as 3-glycidoxy propyl trimethoxy silane and β-(3,4-epoxy cyclohexyl) ethyl trimethoxy silane.

The above adhesion promoters may be used alone or in combination of two or more. Reaction products of various silane coupling agents may also be used.

The amount of adhesion promoter used is preferably 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Plasticizer>
A plasticizer may be added to the composition of the present invention. Specific examples of the plasticizer include phthalate compounds such as dibutyl phthalate, diisononyl phthalate (DINP), diheptyl phthalate, di(2-ethylhexyl)phthalate, diisodecyl phthalate (DIDP), and butyl benzyl phthalate; terephthalate compounds such as bis(2-ethylhexyl)-1,4-benzenedicarboxylate; non-phthalate compounds such as 1,2-cyclohexanedicarboxylate diisononyl ester; aliphatic polycarboxylic acid ester compounds such as dioctyl adipate, dioctyl sebacate, dibutyl sebacate, diisodecyl succinate, and acetyl tributyl citrate; unsaturated fatty acid ester compounds such as butyl oleate and methyl acetylricinoleate; alkylsulfonic acid phenyl esters; phosphate ester compounds; trimellitic acid ester compounds; chlorinated paraffin; hydrocarbon oils such as alkyl diphenyls and partially hydrogenated terphenyls; process oils; and epoxy plasticizers such as epoxidized soybean oil and epoxy benzyl stearate.

Polymer plasticizers can also be used. Specific examples of polymer plasticizers include vinyl polymers; polyester plasticizers; polyether polyols such as polyethylene glycol and polyoxypropylene glycol with a number average molecular weight of 500 or more, and polyethers such as derivatives in which the hydroxyl groups of these polyether polyols are converted to ester groups, ether groups, etc.; polystyrenes; polybutadiene, polybutene, polyisobutylene, butadiene-acrylonitrile, polychloroprene, etc.

The amount of plasticizer used is preferably 5 to 150 parts by weight, more preferably 10 to 120 parts by weight, and particularly preferably 20 to 100 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B). The plasticizer may be used alone or in combination of two or more kinds.

<Anti-sagging agent>
The composition of the present invention may contain an anti-sagging agent as necessary to prevent sagging and improve workability. The anti-sagging agent is not particularly limited, but examples thereof include polyamide waxes; hydrogenated castor oil derivatives; and metal soaps such as calcium stearate, aluminum stearate, and barium stearate. These anti-sagging agents may be used alone or in combination of two or more.

The amount of the sagging prevention agent used is preferably 0.1 to 20 parts by weight per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Antioxidants>
An antioxidant (antiaging agent) can be used in the composition of the present invention. Use of an antioxidant can improve the weather resistance of the cured product. Examples of antioxidants include hindered phenol-based, monophenol-based, bisphenol-based, and polyphenol-based antioxidants. Specific examples of antioxidants are also described in JP-A-4-283259 and JP-A-9-194731.

The amount of antioxidant used is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the total of reactive silicon group-containing polyoxyalkylene polymer (A) and reactive silicon group-containing polyoxyalkylene polymer (B).

<Light stabilizers>
A light stabilizer can be used in the composition of the present invention. The use of a light stabilizer can prevent photooxidative deterioration of the cured product. Examples of light stabilizers include benzotriazole-based, hindered amine-based, and benzoate-based compounds, with hindered amine-based compounds being particularly preferred.

The amount of light stabilizer used is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Ultraviolet absorbing agent>
The composition of the present invention can use an ultraviolet absorber. The use of an ultraviolet absorber can improve the surface weather resistance of the cured product. Examples of ultraviolet absorbers include benzophenone-based, benzotriazole-based, salicylate-based, substituted acrylonitrile-based and metal chelate-based compounds, and benzotriazole-based compounds are particularly preferred, and examples of such compounds include those commercially available under the names Tinuvin P, Tinuvin 213, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329 and Tinuvin 571 (all manufactured by BASF).

The amount of the UV absorber used is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Physical property adjusters>
The curable composition of the present invention may contain a physical property adjuster for adjusting the tensile properties of the resulting cured product, as necessary. The physical property adjuster is not particularly limited, but examples thereof include alkylalkoxysilanes such as phenoxytrimethylsilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, and n-propyltrimethoxysilane; arylalkoxysilanes such as diphenyldimethoxysilane and phenyltrimethoxysilane; alkylisopropenoxysilanes such as dimethyldiisopropenoxysilane, methyltriisopropenoxysilane, and 3-glycidoxypropylmethyldiisopropenoxysilane; trialkylsilylborates such as tris(trimethylsilyl)borate and tris(triethylsilyl)borate; silicone varnishes; and polysiloxanes. By using the physical property adjuster, the hardness of the composition of the present invention when cured can be increased, or conversely, the hardness can be reduced, and the breaking elongation can be obtained. The physical property adjuster may be used alone, or two or more types may be used in combination.

In particular, compounds that produce compounds having monovalent silanol groups in the molecule upon hydrolysis have the effect of reducing the modulus of the cured product without increasing the stickiness of the surface of the cured product. Compounds that produce trimethylsilanol are particularly preferred. Examples of compounds that produce compounds having monovalent silanol groups in the molecule upon hydrolysis include silicon compounds that are derivatives of alcohols such as hexanol, octanol, phenol, trimethylolpropane, glycerin, pentaerythritol, and sorbitol and produce silane monool upon hydrolysis. Specific examples include phenoxytrimethylsilane, tris((trimethylsiloxy)methyl)propane, etc., and it is preferable to use both phenoxytrimethylsilane and tris((trimethylsiloxy)methyl)propane.

The amount of the property adjuster used is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Tackifying Resin>
In the present invention, a tackifier resin can be added for the purpose of increasing the adhesiveness or adhesion to the substrate or for other reasons. There are no particular limitations on the tackifier resin, and any commonly used resin can be used.

Specific examples include terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene-phenol resins, phenol resins, modified phenol resins, xylene-phenol resins, cyclopentadiene-phenol resins, coumarone-indene resins, rosin resins, rosin ester resins, hydrogenated rosin ester resins, xylene resins, low molecular weight polystyrene resins, styrene copolymer resins, styrene block copolymers and their hydrogenated products, petroleum resins (e.g., C5 hydrocarbon resins, C9 hydrocarbon resins, C5C9 hydrocarbon copolymer resins, etc.), hydrogenated petroleum resins, DCPD resins, etc. These may be used alone or in combination of two or more.

The amount of tackifier resin used is preferably 2 to 100 parts by weight, more preferably 5 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, per 100 parts by weight of the total of reactive silicon group-containing polyoxyalkylene polymer (A) and reactive silicon group-containing polyoxyalkylene polymer (B). If it is less than 2 parts by weight, it is difficult to obtain adhesion and adhesion to the substrate, and if it exceeds 100 parts by weight, the viscosity of the composition may become too high, making it difficult to handle.

<Compound containing an epoxy group>
In the composition of the present invention, a compound containing an epoxy group can be used. The use of a compound having an epoxy group can improve the restorability of the cured product. Examples of the compound having an epoxy group include epoxidized unsaturated fats and oils, epoxidized unsaturated fatty acid esters, alicyclic epoxy compounds, compounds shown in epichlorohydrin derivatives, and mixtures thereof. Specific examples include epoxidized soybean oil, epoxidized linseed oil, bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS), epoxy octyl stearate, and epoxy butyl stearate. The epoxy compound is preferably used in the range of 0.5 to 50 parts by weight per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<Photocurable substances>
A photocurable material can be used in the composition of the present invention. When a photocurable material is used, a film of the photocurable material is formed on the surface of the cured product, improving the stickiness and weather resistance of the cured product. Many compounds of this type are known, such as organic monomers, oligomers, resins, and compositions containing them. Representative compounds that can be used include unsaturated acrylic compounds, which are monomers, oligomers, or mixtures thereof having one or several acrylic or methacrylic unsaturated groups, polyvinyl cinnamates, and azido resins.

The photocurable substance should be used in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B). If it is less than 0.1 part by weight, there is no effect of improving weather resistance, and if it is more than 20 parts by weight, the cured product becomes too hard and tends to crack.

<Oxygen-curable substances>
An oxygen-curable substance can be used in the composition of the present invention. Examples of oxygen-curable substances include unsaturated compounds that can react with oxygen in the air, which react with oxygen in the air to form a cured film near the surface of the cured product, preventing the surface from becoming sticky and preventing dirt and dust from adhering to the surface of the cured product. Specific examples of oxygen-curable substances include drying oils such as tung oil and linseed oil, and various alkyd resins obtained by modifying these compounds; acrylic polymers, epoxy resins, and silicone resins modified with drying oils; and liquid polymers such as 1,2-polybutadiene, 1,4-polybutadiene, and polymers of C5 to C8 dienes obtained by polymerizing or copolymerizing diene compounds such as butadiene, chloroprene, isoprene, and 1,3-pentadiene. These may be used alone or in combination of two or more types.

The amount of oxygen-curable substance used is preferably in the range of 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of reactive silicon group-containing polyoxyalkylene polymer (A) and reactive silicon group-containing polyoxyalkylene polymer (B). If the amount used is less than 0.1 part by weight, the improvement in stain resistance will not be sufficient, and if it exceeds 20 parts by weight, the tensile properties of the cured product will tend to be impaired. As described in JP-A-3-160053, it is recommended that the oxygen-curable substance be used in combination with a photocurable substance.

<Epoxy resin>
The composition of the present invention can be used in combination with an epoxy resin. The composition containing an epoxy resin is particularly suitable as an adhesive, particularly as an adhesive for exterior wall tiles. Examples of the epoxy resin include bisphenol A type epoxy resins and novolac type epoxy resins.

The weight ratio of these epoxy resins to the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B) is in the range of [(A) + (B)] / epoxy resin = 100/1 to 1/100. If the ratio of [(A) + (B)] / epoxy resin is less than 1/100, it becomes difficult to obtain the effect of improving the impact strength and toughness of the cured epoxy resin, and if the ratio of [(A) + (B)] / epoxy resin exceeds 100/1, the strength of the cured polymer becomes insufficient.

When an epoxy resin is added, a curing agent for curing the epoxy resin can be used in combination with the composition of the present invention. There are no particular limitations on the epoxy resin curing agent that can be used, and any commonly used epoxy resin curing agent can be used.

When using an epoxy resin hardener, the amount used is in the range of 0.1 to 300 parts by weight per 100 parts by weight of epoxy resin.

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

When the curable composition is a one-component type, all of the ingredients are mixed in advance, so it is preferable to dehydrate and dry ingredients that contain water before use, or to dehydrate them by reducing pressure during mixing. In addition to the dehydration and drying method, storage stability can be further improved by adding an alkoxysilane compound such as n-propyltrimethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, or 3-glycidoxypropyltrimethoxysilane.

The amount of the dehydrating agent, particularly the silicon compound capable of reacting with water such as vinyltrimethoxysilane, used is preferably in the range of 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B).

<<Applications>>
The curable composition of the present invention can be used as an adhesive composition such as a floor adhesive, a tile adhesive, etc. The curable composition of the present invention can also be used as a sealant composition for use in buildings, ships, automobiles, roads, etc. Furthermore, it can also be used as a coating agent, a pressure sensitive adhesive, a mold release agent, a vibration isolating material, a vibration damping material, a soundproofing material, a foaming material, etc.

Among the above applications, the curable composition of the present invention is more preferably used as a sealant composition or an adhesive composition. Furthermore, the curable composition of the present invention is more preferably used as a wood floor adhesive or a tile adhesive, which are applications in which high hardness is particularly required.

The method of the present invention will be specifically explained below with examples, but the present invention is not limited to these examples.

The number average molecular weights in the examples are GPC molecular weights measured under the following conditions:

Liquid delivery system: Tosoh HLC-8220GPC
Column: Tosoh TSKgel Super H series Solvent: THF
Molecular weight: polystyrene equivalent Measurement temperature: 40°C
The average number of reactive silicon groups per terminal structure of the polymer shown in the examples, the average number of reactive silicon groups per molecule, and the average total number of reactive silicon groups, terminal olefin groups, and internal olefin groups per terminal structure were calculated from the polymer structure and the results of NMR measurement.

(Synthesis Example 1-1) Polymer (C-1)
Using polyoxypropylene glycol with a number average molecular weight of about 4,500 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a linear copolymer with a number average molecular weight of about 15,000 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-1) was obtained.

(Synthesis Example 1-2) Polymer (C-2)
Using polyoxypropylene triol having a number average molecular weight of about 4,000 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a branched chain having a number average molecular weight of about 14,000 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-2) was obtained.

(Synthesis Example 1-3) Polymer (C-3)
Using polyoxypropylene glycol with a number average molecular weight of about 4,500 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a linear copolymer with a number average molecular weight of about 10,500 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-3) was obtained.

(Synthesis Example 1-4) Polymer (C-4)
Using polyoxypropylene triol having a number average molecular weight of about 4,000 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a branched chain having a number average molecular weight of about 26,000 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-4) was obtained.

(Synthesis Example 1-5) Polymer (C-5)
Using polyoxypropylene glycol with a number average molecular weight of about 4,500 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a linear copolymer with a number average molecular weight of about 28,000 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-5) was obtained.

(Synthesis Example 1-6) Polymer (C-6)
Using polyoxypropylene triol having a number average molecular weight of about 4,000 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a branched chain having a number average molecular weight of about 7,000 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-6) was obtained.

(Synthesis Example 1-7) Polymer (C-7)
Using polyoxypropylene triol having a number average molecular weight of about 4,000 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a branched chain having a number average molecular weight of about 10,500 is obtained. As a result, a hydroxyl-terminated polyoxypropylene (C-7) was obtained.

(Synthesis Example 1-8) Polymer (C-8)
Using polyoxypropylene glycol with a number average molecular weight of about 4,500 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a linear propylene oxide with a number average molecular weight of about 21,000 is obtained. Hydroxyl-terminated polyoxypropylene (C-8) was obtained.

(Synthesis Example 1-9) Polymer (C-9)
Using a mixture of polyoxypropylene glycol and butanol having a number average molecular weight of about 4,500 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value. The number average molecular weight is about 16,000. Thus, a linear single-terminated hydroxyl group-terminated polyoxypropylene (C-9) was obtained. The ratio of linear components to single-terminated components in (C-9) was approximately 7/3.

(Synthesis Example 1-10) Polymer (C-10)
Using polyoxypropylene glycol with a number average molecular weight of about 4,500 as an initiator, propylene oxide is polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reaches the following value, and a linear propylene oxide with a number average molecular weight of about 19,000 is obtained. Hydroxyl-terminated polyoxypropylene (C-10) was obtained.

(Synthesis Example 2-1) Polymer (A-1)
A methanol solution of 1.0 equivalent of sodium methoxide relative to the hydroxyl groups of the polymer (C-1) was added, and the methanol was distilled off at 140° C., and 1.0 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 3.4 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 4° C. to obtain a linear polyoxyethylene ether having a number average molecular weight of about 15,000 and an average of 1.5 methyldimethoxysilyl groups per terminal structure and an average of 3.0 methyldimethoxysilyl groups per molecule. Propylene (A-1) was obtained. The total number of reactive silicon groups, terminal olefin groups and internal olefin groups in the terminal structures of polyoxypropylene (A-1) was 2.0 on average per terminal structure.

(Synthesis Example 2-2) Polymer (A-2)
A methanol solution of sodium methoxide in an amount of 1.0 equivalent relative to the hydroxyl groups of the polymer (C-2) was added, and the methanol was distilled off at 140° C., and 0.5 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 3.3 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 4° C. to obtain a branched polyoxyethylene copolymer having a number average molecular weight of about 15,000 and an average of 1.1 methyldimethoxysilyl groups per terminal structure and an average of 3.3 methyldimethoxysilyl groups per molecule. Propylene (A-2) was obtained. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures of polyoxypropylene (A-2) was 1.5 on average per terminal structure.

(Synthesis Example 2-3) Polymer (A-3)
A methanol solution of sodium methoxide in an amount of 1.0 equivalent relative to the hydroxyl groups of the polymer (C-3) was added, and the methanol was distilled off at 140° C., and 0.5 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 3.4 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 4° C. to obtain a linear polyoxyethylene ether having a number average molecular weight of about 11,000 and an average of 1.1 methyldimethoxysilyl groups per terminal structure and an average of 2.2 methyldimethoxysilyl groups per molecule. Propylene (A-3) was obtained. The total number of reactive silicon groups, terminal olefin groups and internal olefin groups in the terminal structures of the polyoxypropylene (A-3) was 1.5 on average per terminal structure.

(Synthesis Example 2-4) Polymer (A-4)
A methanol solution of 1.0 equivalent of sodium methoxide relative to the hydroxyl groups of the polymer (C-4) was added, and the methanol was distilled off at 140° C., and 1.0 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 2.6 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 40° C. to obtain a branched polyoxyethylene ether having a number average molecular weight of about 27,000 and an average of 1.5 methyldimethoxysilyl groups per terminal structure and an average of 4.5 methyldimethoxysilyl groups per molecule. Propylene (A-4) was obtained. The total number of reactive silicon groups, terminal olefin groups and internal olefin groups in the terminal structures of polyoxypropylene (A-4) was 2.0 on average per terminal structure.

(Synthesis Example 2-5) Polymer (A-5)
A methanol solution of 1.0 equivalent of sodium methoxide relative to the hydroxyl groups of the polymer (C-5) was added, and the methanol was distilled off at 140° C., and 1.0 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 1.7 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 4° C. to obtain a linear polyoxyethylene ether having a number average molecular weight of about 29,000 and an average of 1.5 methyldimethoxysilyl groups per terminal structure and an average of 3.0 methyldimethoxysilyl groups per molecule. Propylene (A-5) was obtained. The total number of reactive silicon groups, terminal olefin groups and internal olefin groups in the terminal structures of polyoxypropylene (A-5) was 2.0 on average per terminal structure.

(Synthesis Example 2-6) Polymer (A-6)
A methanol solution of sodium methoxide in an amount of 1.0 equivalent relative to the hydroxyl groups of the polymer (C-8) was added, and the methanol was distilled off at 140° C., and 0.3 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 1.5 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 4° C. to obtain a linear polyoxyethylene ether having a number average molecular weight of about 21,000 and an average of 0.9 methyldimethoxysilyl groups per terminal structure and an average of 1.8 methyldimethoxysilyl groups per molecule. Propylene (A-6) was obtained. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures of polyoxypropylene (A-6) was 1.3 on average per terminal structure.

(Synthesis Example 2-7) Polymer (A-7)
A methanol solution of sodium methoxide in an amount of 1.0 equivalent relative to the hydroxyl groups of the polymer (C-9) was added, and the methanol was distilled off at 140° C., and 0.5 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 1.7 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours at 40° C. to obtain a linear polyoxyethylene copolymer having a number average molecular weight of about 16,000 and a mixed methyldimethoxysilyl group at one end and an average of 0.9 methyldimethoxysilyl groups per terminal structure and an average of 1.8 methyldimethoxysilyl groups per molecule. Propylene (A-7) was obtained. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structure of polyoxypropylene (A-7) was 1.3 on average per terminal structure. The ratio of linear components to single-end components in the polymer (7) was approximately 7/3.

(Synthesis Example 2-8) Polymer (A-8)
A methanol solution of sodium methoxide in an amount of 1.0 equivalent relative to the hydroxyl groups of the polymer (C-10) was added, and the methanol was distilled off at 140° C., and 0.3 equivalent of allyl glycidyl ether was added at 140° C. The reaction was carried out for 2 hours to introduce a structure containing an allyl group and a hydroxyl group, and then 1.5 equivalents of 3-chloro-1-propene was added at 130° C. to convert the hydroxyl group to an allyl group. Thereafter, 36 ppm of platinum divinyldisiloxane complex (a 3% by weight isopropyl alcohol solution calculated as platinum) and 1.6 parts by weight of methyldimethoxysilane were added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene, and the mixture was heated at 90° C. The reaction was carried out for 2 hours to obtain a linear polyoxypropylene ( A-8) was obtained. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures of polyoxypropylene (A-8) was 1.3 on average per terminal structure.

(Synthesis Example 3-1) Polymer (B-1)
A methanol solution of 1.2 equivalents of sodium methoxide was added to the hydroxyl groups of polyoxypropylenetriol having a number-average molecular weight of about 4,000, and the methanol was distilled off at 130° C. to obtain 1.5 equivalents of 3-chloro- 1-Propene was added at 130° C. to convert the hydroxyl groups to allyl groups. After removing the remaining salts, a platinum divinyldisiloxane complex (calculated as platinum) was added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene. 3% by weight isopropyl alcohol solution) and 8.1 parts by weight of methyldimethoxysilane were added and reacted at 90° C. for 2 hours to obtain a silane having a number average molecular weight of about 4,500 and an average of 0.7 per terminal structure. Thus, a branched chain polyoxypropylene (B-1) having an average of 2.1 methyldimethoxysilyl groups per molecule was obtained. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures of the polyoxypropylene (B-1) was 1.0 on average per terminal structure.

(Synthesis Example 3-2) Polymer (B-2)
A methanol solution of 1.2 equivalents of sodium methoxide was added to the hydroxyl groups of polyoxypropylene glycol having a number-average molecular weight of about 4,500, and the methanol was distilled off at 130° C. to obtain 1.5 equivalents of 3-chloro- 1-Propene was added at 130° C. to convert the hydroxyl groups to allyl groups. After removing the remaining salts, a platinum divinyldisiloxane complex (calculated as platinum) was added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene. 3.3 mass% isopropyl alcohol solution) and 6.0 parts by weight of methyldimethoxysilane were added and reacted at 90° C. for 2 hours to obtain a silane having a number average molecular weight of about 5,000 and an average of 0.7 per terminal structure. As a result, a linear polyoxypropylene (B-2) having an average of 1.4 methyldimethoxysilyl groups per molecule was obtained. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups in the terminal structures of the polyoxypropylene (B-2) was 1.0 on average per terminal structure.

(Synthesis Example 3-3) Polymer (B-3)
A methanol solution of sodium methoxide in an amount of 1.2 equivalents relative to the hydroxyl groups of the polymer (C-6) was added, and methanol was distilled off at 130° C., and 1.5 equivalents of 3-chloro-1-propene was added at 130° C. After removing the remaining salts, a platinum divinyldisiloxane complex (3% by mass in terms of platinum isopropyl disiloxane) was added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene. The resulting mixture was reacted at 90°C for 2 hours to produce a silane having a number average molecular weight of about 8,000, an average of 0.8 units per terminal structure, and an average of 0.8 units per molecule. A branched polyoxypropylene (B-3) having an average of 2.4 methyldimethoxysilyl groups was obtained. The reactive silicon group and the terminal olefin group in the terminal structure of polyoxypropylene (B-3) were The total number of internal olefin groups introduced was 1.0 on average per one terminal structure.

(Synthesis Example 3-4) Polymer (B-4)
A methanol solution of sodium methoxide in an amount of 1.2 equivalents relative to the hydroxyl groups of the polymer (C-7) was added, and methanol was distilled off at 130° C., and 1.5 equivalents of 3-chloro-1-propene was added at 130° C. After removing the remaining salts, a platinum divinyldisiloxane complex (3% by mass in terms of platinum isopropyl disiloxane) was added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene. The resulting mixture was reacted at 90° C. for 2 hours to produce a silane having a number average molecular weight of about 11,000, an average of 0.7 units per terminal structure, and an average of 0.7 units per molecule. A branched polyoxypropylene (B-4) having an average of 2.1 methyldimethoxysilyl groups was obtained. The reactive silicon group and the terminal olefin group in the terminal structure of polyoxypropylene (B-4) were The total number of internal olefin groups introduced was 1.0 on average per one terminal structure.

(Synthesis Example 4-1) Polymer (H-1)
Using n-butanol as an initiator, propylene oxide was polymerized with zinc hexacyanocobaltate glyme complex catalyst until the molecular weight reached the following value, to obtain polyoxypropylene having a hydroxyl group at one end and a number average molecular weight of about 8000. Then, 1.2 equivalents of sodium methoxide in methanol was added to the hydroxyl group of the hydroxyl-terminated polyoxypropylene, and methanol was distilled off at 130° C. to obtain 1.5 equivalents of 3-chloro-1-propene. was added at 130° C. to convert the hydroxyl groups to allyl groups. After removing the remaining salts, a platinum divinyldisiloxane complex (3% by mass in terms of platinum) was added to 100 parts by weight of the obtained allyl-terminated polyoxypropylene. The mixture was reacted at 90° C. for 2 hours to obtain polyoxypropylene (H -1) was obtained. It was found that the polymer (H-1) had an average of 0.8 dimethoxymethylsilyl groups at only one end, and an average of 0.4 per molecule. The total number of reactive silicon groups, terminal olefin groups, and internal olefin groups was 0.5 on average per one terminal structure.

(Examples 1 to 11, Comparative Examples 1 to 3)
Polymers (A-1) to (A-8), polymers (B-1) to (B-4) obtained in the above Synthesis Examples, and polymer (B'-1) (polyoxypropylene triol (Actocol 96-56, manufactured by Mitsui Chemicals SKC Polyurethanes, Inc.)) were mixed in the blending ratios shown in Table 1 to prepare a base polymer. The viscosity of the base polymer was measured by the following measurement method. The results are shown in Table 1.

(viscosity)
The viscosity of the base polymer was measured at 23° C. and a relative humidity of 50% using an E-type viscometer (Tokyo Keiki Co., Ltd., measuring cone: 3° C.×R14).

(Method of Evaluating Composition Properties)
Curable compositions were prepared using the additives shown below per 100 parts by weight of the base polymer. First, the plasticizer, each filler, and antioxidant shown below were mixed and thoroughly mixed, and then the mixture was dispersed by passing through three paint rolls three times to prepare a master batch. Thereafter, the polymer or each polymer blend shown in Table 1 as the base polymer, the dehydrating agent, the adhesion imparting agent, and the curing catalyst shown below were added to the prepared master batch and thoroughly mixed, and the mixture was uniformly kneaded and defoamed using a planetary mixer to prepare each curable composition. Various test specimens were prepared using each prepared curable composition, and various evaluations were performed. Since the additives other than the base polymer were the same, the notation in Table 1 is omitted.
Plasticizer: Polyoxypropylene glycol (Actocol P-23, manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.), 50 parts by weight Filler:
(i) fatty acid-treated precipitated calcium carbonate (Hakuenka CCR, manufactured by Shiraishi Kogyo Co., Ltd.), 30 parts by weight
(ii) Heavy calcium carbonate (Whiten SB Red, manufactured by Shiraishi Calcium Co., Ltd.), 150 parts by weight Antioxidant: Irganox 1010 (hindered phenol-based antioxidant, manufactured by BASF SE), 1 part by weight Dehydrating agent: vinyltrimethoxysilane (A-171, manufactured by Momentive Performance Materials Inc.), 3 parts by weight Adhesion imparting agent: 3-(N-2-aminoethylamino)propyltrimethoxysilane (A-1120, manufactured by Momentive Performance Materials Inc.), 3 parts by weight Curing catalyst: dibutyltin bis(acetoacetonate) (U-220H, manufactured by Nitto Kasei Co., Ltd.), 1 part by weight

(evaluation)
The dumbbell properties, tensile shear strength and tear strength of the prepared curable compositions were measured by the following methods. The results are also shown in Table 1.

(Dumbbell properties)
The curable composition was filled into a 3 mm thick sheet mold at 23°C and 50% relative humidity. After curing for 3 days at 23°C and 50% relative humidity, the composition was aged in a 50°C dryer for 4 days to obtain a sheet-like cured product. The obtained cured product was punched into a No. 3 dumbbell-shaped test piece according to JIS K 6251. Using the obtained test piece, a tensile test (tensile speed 200 mm/min) was performed using an autograph at 23°C and 50% relative humidity to measure the stress at 30% elongation (M30), the stress at break (tensile strength TB), and the elongation at break (EB).

(tensile shear strength)
The curable composition was applied to wood (birch) as an adherend at a thickness of 50 μm and an adhesive area of 25 mm×25 mm at 23° C. and 50% relative humidity, and the adherends were immediately bonded together. The composition was cured for 7 days at 23° C. and 50% relative humidity, and a tensile shear test (tensile speed 50 mm/min) was performed using an autograph to measure the breaking stress (TB).

(Tear strength)
The curable composition was filled into a sheet-shaped mold having a thickness of 3 mm at 23° C. and 50% relative humidity. After curing for 3 days at 23° C. and 50% relative humidity, the composition was aged in a 50° C. dryer for 4 days to obtain a sheet-shaped cured product. The obtained cured product was punched into a dumbbell shape (JIS A type) for tear test to obtain a test piece. The obtained test piece was subjected to a tear test (tensile speed 200 mm/min) using an autograph at 23° C. and 50% relative humidity to measure the stress at break (TB).

Example 12
The evaluation was carried out in the same manner as in Example 1 except that 10 parts by weight of polymer (H) was further added, and the results are shown in Table 1.

The above results show that, in contrast to Comparative Example 1, which uses only polymer (A) and has a high polymer viscosity, Comparative Example 2, which uses comparative polymer (B'-1) instead of polymer (B) to reduce viscosity, has reduced tensile strength and tensile shear strength. Furthermore, Comparative Example 3, which uses only polymer (B), has low tensile strength, tensile shear strength, and tear strength. However, Examples 1 to 12, which use polymer (A) and polymer (B), have high tensile strength despite their low viscosity.

Furthermore, Examples 1 to 4 and 12, which use a polymer (A) with a number average molecular weight of 12,000 to 25,000 and an average of 1.2 or more silyl groups per terminal, have high tensile strength and also higher tear strength.

Furthermore, in Example 1, which uses a polymer having a number average molecular weight of 1,000 to 6,000 and a branched main chain as polymer (B), the elongation is further improved, and a cured product having similar tensile strength, tensile shear strength, tear strength, and elongation is obtained, despite its lower viscosity compared to Comparative Example 1.

Claims (11)

General formula (1):
-Si(R ¹ ) _3-a (X) _a (1)
(In the formula, each R ¹ independently 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. a is 1, 2, or 3.)
a reactive silicon group-containing polyoxyalkylene polymer (A) having a reactive silicon group represented by the formula :
a reactive silicon group-containing polyoxyalkylene polymer (B) having a reactive silicon group represented by general formula (1), the reactive silicon group-containing polyoxyalkylene polymer (B) having a terminal structure having a reactive silicon group, a terminal olefin group and/or an internal olefin group, the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure being 1.0 or less on average per terminal structure, the number of reactive silicon groups contained in one molecule being 1.1 to 4.0 on average, and the reactive silicon group-containing polyoxyalkylene polymer (B) having a branched polymer skeleton ;
A curable composition comprising:
a blend of the reactive silicon group-containing polyoxyalkylene polymer (A) and the reactive silicon group-containing polyoxyalkylene polymer (B) has a viscosity at 23°C of 6.0 Pa s or less, and the number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (B) is smaller by 3,000 or more than the number average molecular weight of the reactive silicon group-containing polyoxyalkylene polymer (A);
A curable composition comprising a reactive silicon group-containing polyoxyalkylene polymer (A) and a reactive silicon group-containing polyoxyalkylene polymer (B) in a weight ratio (A)/(B) of 50/50 to 95/5 . The terminal portion of the reactive silicon group-containing polyoxyalkylene polymer (A) is represented by the general formula (2):

(wherein R ¹ , X, and a are the same as defined above; R ² and R ⁴ each independently represent a divalent linking group having 1 to 6 carbon atoms which may contain a heteroatom; ^{R 3} and R ⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; and n is an integer of 1 to 10). The curable composition according to claim 1, having a structure represented by the following formula: The curable composition according to claim 1 or 2, wherein the reactive silicon group-containing polyoxyalkylene polymer (A) has a number average molecular weight of 12,000 to 25,000. The curable composition according to any one of claims 1 to 3, wherein the number of reactive silicon groups per terminal structure of the reactive silicon group-containing polyoxyalkylene polymer (A) is 1.2 or more on average. The curable composition according to any one of claims 1 to 4, wherein the weight ratio (A)/(B) of the reactive silicon group-containing polyoxyalkylene polymer (A) to the reactive silicon group-containing polyoxyalkylene polymer (B) is 60/40 to 95/5. The curable composition according to any one of claims 1 to 5, wherein the number of reactive silicon groups contained in one molecule of the reactive silicon group-containing polyoxyalkylene polymer (B) is, on average, 1.4 to 3.0. The curable composition according to any one of claims 1 to 6 , wherein the reactive silicon group-containing polyoxyalkylene polymer (B) has a number average molecular weight of 3,000 to 6,000. The curable composition according to any one of claims 1 to 7, further comprising a reactive silicon group-containing polyoxyalkylene polymer (H) in which the terminal structure has a reactive silicon group, a terminal olefin group and/or an internal olefin group, the total number of the reactive silicon groups, the terminal olefin groups and the internal olefin groups in the terminal structure is on average 1.0 or less per terminal structure, and the number of reactive silicon groups contained in one molecule is on average less than 1.1. A cured product obtained by curing the curable composition according to any one of claims 1 to 8 . An adhesive composition comprising the curable composition according to any one of claims 1 to 8 . A sealant composition comprising the curable composition according to any one of claims 1 to 8 .