JPH11241029A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition having a low tacking property and a good core curability in a low modulus region. SOLUTION: The titled composition contains an organic polymer (A) having a molecular weight of 2,000 or larger and at least one hydrolyzable silicon group which is crosslinkable through hydrolysis in a molecule and a compound (B) having a molecular weight of 1,000 or smaller and at least 2.1 trimethylsilyloxy group in a molecule. Preferably, the hydrolyzable silicon group is a group of the formula: -SiXa R<1> 3-a (wherein R<1> is a substituted or unsubstituted, monovalent hydrocarbon group having a carbon number of from 1 to 20; X is a hydroxyl group or a monovalent hydrolyzable group; and a is an integer of from 1 to 3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a room temperature curable composition which cures in the presence of moisture.

[0002]

2. Description of the Related Art Organic polymers having one or more hydrolyzable silicon groups in the molecule are used for sealing materials, adhesives, coating materials and the like, taking advantage of the characteristic that the cured product has rubber elasticity. And several examples are conventionally known.

However, when the modulus of the cured product or the cured product of a composition containing the polymer is reduced, the tackiness of the surface (hereinafter referred to as tack) of the polymer remains even after the curing is completed. When used for such purposes, they cause joint contamination such as adhesion of dust and cause damage to the appearance of the building.

For the purpose of preventing this tack, for example, Japanese Patent Application Laid-Open No. 64-9268 discloses a rubber-based organic polymer having a reactive silicon functional group which can be crosslinked by forming a siloxane bond in the molecule and a specific structure. A curable composition containing an organosilicon compound having the same is disclosed. Although this method is effective for improving the initial tack, it has a large difference in curing speed between the surface and the inside, causing poor curing and surface skinning, and limiting the pot life. Had been a constraint.

Japanese Patent Application Laid-Open No. Hei 6-279693 discloses that a compound having at least one hydrolyzable silicon-containing group capable of being crosslinked by hydrolysis at the terminal or in the side chain of a polymer, and a monosilanol-containing compound being hydrolyzed. There is disclosed a polymer having at least one silicon-containing group that can be used as an active ingredient. Attempts have been made to improve the deep-side curability together with the improvement in tack, but the effect of improvement is seen to some extent but is insufficient depending on the use conditions. there were.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, to improve tack and to improve the deep curing property.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is an organic compound having at least one hydrolyzable silicon group crosslinkable by hydrolysis and having a molecular weight of 2,000 or more. A curable composition comprising a polymer (A) and a compound (B) having a molecular weight of 1,000 or less having 2.1 or more trimethylsilyloxy groups in a molecule.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the organic polymer (A) having at least one hydrolyzable silicon group crosslinkable by hydrolysis in the present invention, an organic polymer selected from polyethers, polyesters and polycarbonates And organic polymers derived therefrom.

Also, a polymerizable monomer such as (meth) acrylic acid ester, vinyl alkyl ether, isobutylene, butadiene, chloroprene or the like, a polymerizable monomer such as chlorotrifluoroethylene, tetrafluoroethylene, ethylene or propylene, and a polymer containing a hydrolyzable silicon group. And a hydrolyzable silicon-containing vinyl polymer obtained by copolymerizing a hydrophilic monomer.

[0010] Particularly, an organic polymer derived from an organic polymer selected from polyether, polyester and polycarbonate is preferable, and a hydrolyzable silicon group-containing polyether derived from polyether is particularly preferable.

[0011] The hydrolyzable silicon group-containing polyether is
It is particularly preferred that it is derived from a hydroxyl-containing polyether.

The hydroxyl group-containing polyether is obtained by subjecting an initiator containing active hydrogen to a ring-opening polymerization reaction of a cyclic ether in the presence of a catalyst. Cyclic ether alkylene oxide is preferred, and propylene oxide, ethylene oxide, butylene oxide, epichlorohydrin, styrene oxide, allyl glycidyl ether and the like are preferred. Oxetane, tetrahydrofuran and the like can also be used.

Examples of the initiator include polyvalent active hydrogen compounds such as polyhydric alcohols, polycarboxylic acids and polyamines, monools containing terminal unsaturated groups, unsaturated phenols such as unsaturated phenols and unsaturated carboxylic acids. Active hydrogen compounds.

Examples of the catalyst include alkali metals such as sodium, potassium and cesium, alkali metal compounds such as hydroxides of these alkali metals, double metal cyanide complexes,
Metal porphyrin complexes can be used. It is particularly preferred to use double metal cyanide complexes.

In the present invention, a hydrolyzable silicon group which can be cross-linked by hydrolysis (hereinafter also simply referred to as a hydrolyzable silicon group) is a condensation reaction such as a silanol group or an alkoxysilyl group caused by moisture or a curing catalyst. Which can promote high molecular weight by crosslinking of the organic polymer,
It is preferably represented by Formula 1.

[0016]

## STR2 ## -SiX _a R ¹ _3-a ··· Formula 1

In the formula 1, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, X is a hydroxyl group or a monovalent hydrolyzable group, and a is an integer of 1 to 3.

The hydrolyzable silicon group-containing polyether is
When it is derived from a hydroxyl group-containing polyether, a hydrolyzable silicon group represented by Formula 1 is usually introduced via an organic group. Therefore, the organic polymer (A) in the present invention preferably has a group represented by Formula 2.

[0019]

[Formula 3] ^{_{-R 0 -SiX a R 1 3-}} a ··· Formula 2

In the formula 2, R ⁰ is a divalent organic group, R ¹ , X,
a is the same as above.

Here, R ^{0 in} Formula 2 is a divalent organic group, and is preferably a hydrocarbon group having 8 or less carbon atoms. Equation 1, Equation 2
Wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably an alkyl group having 8 or less carbon atoms, a phenyl group or a fluoroalkyl group. Particularly preferred are a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group and a phenyl group.

X in the formulas 1 and 2 is a hydroxyl group or a monovalent hydrolyzable group. Examples of the hydrolyzable group include a halogen atom, an alkoxy group, an acyloxy group, an amide group,
There is an amino group, an aminooxy group, a ketoximate group or a hydride group. Among these, the number of carbon atoms of the hydrolyzable group having a carbon atom is preferably 6 or less, particularly preferably 4 or less. Preferred X is an alkoxy group having 4 or less carbon atoms, particularly a methoxy group, an ethoxy group or a propoxy group. A in Formulas 1 and 2 is preferably 2 or 3.

Examples of the method for producing the organic polymer (A) in the present invention include, but are not limited to, the following (a) to (f). (A) to (d)
It is an example of a manufacturing method of a hydrolyzable silicon group-containing polyether, and (e) to (f) are examples of a method of manufacturing a hydrolyzable silicon group-containing vinyl polymer.

(A) A method in which an organosilicon compound having an isocyanate group and a hydrolyzable silicon group is reacted with a hydroxyl group-containing polyether.

Specific examples of the organosilicon compound include the following compounds.

[0026]

## STR4 ## (C ₂ H ₅ O) ₃ Si (CH ₂ ) ₃ NCO,
(CH ₃ O) ₃ Si (CH ₂ ) ₃ NCO, (CH ₃ O)
₂ (CH ₃ ) Si (CH ₂ ) ₃ NCO, (CH ₃ O) ₃
SiNCO, (CH ₃ O) ₂ Si (NCO) ₂ .

(B) Formula HSix _a R ¹³ _-a (wherein R ¹ ,
X and a are the same as described above), and a polyether having an unsaturated group introduced into a terminal thereof.

Here, as a method for introducing an unsaturated group,
A method in which OH of a hydroxyl group-containing polyether is converted to OM (M is an alkali metal) and then reacted with an unsaturated group-containing halogenated hydrocarbon such as allyl chloride, or a compound having a functional group capable of reacting with an unsaturated group and a hydroxyl group Is reacted with a hydroxyl group-containing polyether to form an ester bond, a urethane bond,
There is a method of introducing an unsaturated group through a carbonate bond or the like. Further, when producing an alkylene oxide in the production of a terminal hydroxyl group-containing polyether, a method of introducing an unsaturated group into a side chain by copolymerizing an unsaturated group-containing alkylene oxide such as allyl glycidyl ether, There is also a method of introducing an unsaturated group into a terminal by using a hydroxyl group-containing polyether produced using an unsaturated group-containing monol.

(C) A method of reacting a polyisocyanate such as tolylene diisocyanate with a terminal of a hydroxyl group-containing polyether to form an isocyanate group terminal, and then reacting the isocyanate group with a W group of a silicon compound represented by Formula 3. .

[0030]

[Of 5] _{^{W-R 2 -SiX a R 1}} 3-a ··· Formula 3

In the formula 3, R ¹ , X and a are the same as described above, and R ² is a divalent hydrocarbon group having 1 to 20 carbon atoms;
W is an active hydrogen-containing group selected from a hydroxyl group, a carboxyl group, a mercapto group and an amino group (primary or secondary).

(D) A method in which an unsaturated group of a polyether having an unsaturated group introduced at the terminal is reacted with a mercapto group of a silicon compound represented by Formula 3 wherein W is a mercapto group.

(E) A method of copolymerizing a polymerizable monomer having a hydrolyzable silicon group or its oligomer with another polymerizable monomer or its oligomer.

The polymerizable monomer is, for example, a single compound of the formula (4) or a mixture of two or more compounds.

[0035]

Embedded image CRR ³ = CR ⁴ R ⁵ Formula 4

In Formula 4, R and R ³ are a hydrogen atom, a halogen atom or a monovalent hydrocarbon group, preferably a hydrogen atom or a monovalent hydrocarbon group. R ⁴ and R ⁵ are a hydrogen atom, a halogen atom, a monovalent hydrocarbon group, a phenyl group,
It is a group selected from an alkoxy group, a carboxyl group, an alkoxycarbonyl group, a glycidoxycarbonyl group, a cyano group, an alkenyl group, an acyloxy group, an amide group and a pyridyl group.

Specific examples of the polymerizable monomer include styrene monomers such as styrene and α-methylstyrene, (meth) acrylic monomers such as (meth) acrylic acid, their esters or (meth) acrylamide, acrylonitrile, Group-containing monomers such as 1,4-dicyanobutene-1, vinyl ester monomers such as vinyl acetate, diene monomers such as isoprene and butadiene, olefins such as isobutylene and other unsaturated esters, halogenated olefins, vinyl ethers and the like. .

As the polymerizable monomer having a hydrolyzable silicon group, a compound represented by Formula 5 is used.

[0039]

Embedded image Y _3-b —SiR ⁶ _b R ⁷ Formula 5

In the formula 5, R ⁶ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and Y is a hydroxyl group, a halogen atom, an alkoxy group, an acyloxy group, an amide group, an amino group, aminoxy group, a hydrolyzable group such as a ketoximate group, R ⁷ is an organic group having a polymerizable unsaturated group, b is an integer of 0-2.

Specific examples of the compound represented by the formula 5 include the following compounds.

[0042]

Embedded image CH ₂ CC (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂ and CH ₂ CC (CH ₃ ) Si (CH ₃ ) (OCH ₃ ) ₂ .

(F) A method of polymerizing a polymerizable monomer in the presence of a chain transfer agent containing a hydrolyzable silicon group.

Specific examples of the chain transfer agent containing a hydrolyzable silicon group include the following compounds.

[0045]

Embedded image HS (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , HS
_{(CH 2) 3 Si (CH} 3) (OCH 3) 2.

The molecular weight of the organic polymer (A) is 2,000 or more. It is more preferably from 3,000 to 50,000, particularly from 5,000 to 30,000, and even more preferably from 8,000 to 50,000
30,000 is preferred.

When a hydrolyzable silicon group-containing polyether is used as the organic polymer (A), its molecular weight is preferably calculated from the hydroxyl value of the starting hydroxyl group-containing polyether.

The total amount of the ionic impurities contained in the organic polymer (A) of the present invention is preferably 50 ppm or less. In particular, the total amount of metal ionic impurities is preferably 20 ppm or less. As a method for reducing ionic impurities, JP-A-6-323113 and JP-A-7-180336 are known.
And the like.

As the curable composition of the present invention, a compound (B) having a molecular weight of 1,000 or less having 2.1 or more trimethylsilyloxy groups in a molecule (hereinafter, referred to as a compound (B) containing a trimethylsilyloxy group) is used.

The compound (B) containing a trimethylsilyloxy group is preferably a compound having a molecular weight of 500 or less.

The number of trimethylsilyloxy groups in the trimethylsilyloxy group-containing compound (B) is 2.1.
The number is preferably 8 or more and 8 or less.

Compounds obtained by reacting a polyhydric alcohol with a known silylating agent to convert the hydroxyl group of the polyhydric alcohol into trimethylsilyloxy are particularly preferred. As the polyhydric alcohol, a compound having three or more hydroxyl groups can be used. The number of hydroxyl groups is preferably from 3 to 8, and particularly preferably 3. Examples of the polyhydric alcohol having three or more hydroxyl groups in a molecule include, but are not limited to, trimethylolpropane, glycerin, pentaerythritol, and sorbitol.

As the silylating agent, 1,1,1,3,3,
Examples include 3-hexamethyldisilazane and trimethylchlorosilane.

The trimethylsilyloxylation ratio in all hydroxyl groups of the polyhydric alcohol can be arbitrarily adjusted.
Or more, and particularly preferably 80% or more. Most preferably, substantially all of the hydroxyl groups are trimethylsilyloxylated.

The amount of the trimethylsilyloxy group-containing compound (B) to be used is not particularly limited, and can be freely set according to the physical properties of the desired cured product. Usually, the amount is 0.1 to 100 parts by weight of the organic polymer (A).
1 to 10 parts by weight, especially 0.1 to 5 parts by weight is preferred.

The trimethylsilyloxy group-containing compound (B) is used in combination with a known monosilanol-generating compound such as a trialkylsilyloxy compound of a monoalcohol or phenoxytrimethylsilane for the purpose of adjusting the curing rate or the like. You may.

The curable composition of the present invention comprises an organic polymer (A)
And the compound (B) containing trimethylsilyloxy group. The method of mixing the organic compound (A) and the compound (B) containing trimethylsilyloxy group is roughly classified into the following two methods.

The first method is to simply add the trimethylsilyloxy group-containing compound (B) to the organic polymer (A). What is necessary is just to adjust the heating and stirring conditions and the like according to the properties of the trimethylsilyloxy group-containing compound (B), and to uniformly disperse and dissolve the compound. In this case, it is not necessary to make the state completely uniform, and even if the state is opaque, the object can be sufficiently achieved if dispersed. If necessary, a dispersion stabilizer such as a surfactant may be used in combination.

The second method is to add and mix a predetermined amount of the compound (B) containing a trimethylsilyloxy group when the final product is used. For example, when used as a two-component sealing material, a compound (B) containing a trimethylsilyloxy group can be used as a third component in addition to the base material and the curing agent.

The curable composition of the present invention may further contain a filler, a plasticizer, a curing catalyst, and other additives as required.

Known fillers can be used as the filler. The amount of the filler to be used is preferably 0 to 1000 parts by weight, particularly preferably 50 to 250 parts by weight, based on 100 parts by weight of the organic polymer (A). Specific examples of the filler include the following. These fillers may be used alone or in combination of two or more.

Calcium carbonate, fumed silica, precipitated silica, silicic anhydride, hydrous silicic acid and carbon black, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, Powdered fillers such as zinc oxide, activated zinc flower, shirasu balloon, wood flour, pulp, cotton chips, mica, walnut flour, fir flour, graphite, aluminum fine powder, flint powder, asbestos, glass fiber, glass filament, Fibrous filler such as carbon fiber, Kevlar fiber and polyethylene fiber.

Known plasticizers can be used as the plasticizer. The use amount of the plasticizer is preferably 0 to 100 parts by weight based on 100 parts by weight of the organic polymer (A). The following are specific examples of the plasticizer.

Dioctyl phthalate, dibutyl phthalate,
Phthalate esters such as butylbenzyl phthalate. Aliphatic carboxylic acid esters such as dioctyl adipate, diisodecyl succinate, dibutyl sebacate and butyl oleate; Alcohol esters such as pentaerythritol ester. Phosphate esters such as trioctyl phosphate and tricresyl phosphate. Epoxy plasticizers such as epoxidized soybean oil, dioctyl 4,5-epoxyhexahydrophthalate, and benzyl epoxy stearate. Chlorinated paraffin. Hydrocarbon plasticizers such as alkylbenzene. Polyester-based plasticizers such as polyesters of dibasic acids and dihydric alcohols, polyethers such as polyoxypropylene glycol and derivatives thereof, poly-α-methylstyrene,
Polymer plasticizers such as oligomers of polystyrene such as polystyrene, oligomers such as polybutadiene, butadiene-acrylonitrile copolymer, polychloroprene, polyisoprene, polybutene, hydrogenated polybutene, and epoxidized polybutadiene.

In curing the curable composition of the present invention, a curing catalyst for accelerating the curing reaction of the hydrolyzable silyl group may be used. Specific examples include the following compounds. One or more of them are used. The curing catalyst is preferably used in an amount of 0 to 10 parts by weight based on 100 parts by weight of the organic polymer (A).

Metal salts such as alkyl titanates, organosilicon titanates, bismuth tris (2-ethylhexoate), acidic compounds such as phosphoric acid, p-toluenesulfonic acid and phthalic acid, ethylenediamine, hexanediamine and the like Aliphatic diamines, aliphatic polyamines such as diethylene triamine, triethylene tetramine, tetraethylene pentamine, heterocyclic amines such as piperidine and piperazine, aromatic amines such as m-phenylenediamine, alkanolamines, dialkanols Amine compounds such as butylamine-2-ethylhexoate and various modified amines used as curing agents for epoxy resins;

Tin dioctylate, dibutyltin dilaurate, dioctyltin dilaurate, carboxylic acid-type organotin compounds of the formula (10), and mixtures of these carboxylic acid-type organic tin compounds with the above amines.

A sulfur-containing organotin compound of the formula

Organic tin oxides such as (nC ₄ H ₉ ) ₂ SnO and (nC ₈ H ₁₇ ) ₂ SnO, and these organic tin oxides and ethyl silicate, dimethyl maleate, diethyl maleate, dioctyl maleate, phthalic acid Reaction products with ester compounds such as dimethyl, diethyl phthalate and dioctyl phthalate.

And the reaction products of these tin compounds with alkoxysilanes (acac is an acetylacetonato ligand, e-aca
c is an acetoacetate ligand).

A tin compound represented by the following formula:

[0072]

Embedded image (nC ₄ H ₉ ) ₂ Sn (OCOCH = CHCOOCH ₃ ) ₂ , (nC ₄ H ₉ ) ₂ S
n (OCOCH = CHCOOC ₄ H ₉ -n) ₂ , (nC ₈ H ₁₇ ) ₂ Sn (OCOCH = CHCOOCH
₃ ) ₂ , (nC ₈ H ₁₇ ) ₂ Sn (OCOCH = CHCOOC ₄ H ₉ -n) ₂ , (nC ₈ H ₁₇ ) ₂
Sn (OCOCH = CHCOOC ₈ H ₁₇ -iso) ₂ .

[0073]

Embedded image (nC ₄ H ₉ ) ₂ Sn (SCH ₂ COO), (nC ₈ H ₁₇ ) ₂ Sn (SCH ₂ C
OO), (nC ₈ H ₁₇ ) ₂ Sn (SCH ₂ CH ₂ COO), (nC ₈ H ₁₇ ) ₂ Sn (SCH ₂ C
OOCH ₂ CH ₂ OCOCH ₂ S), (nC ₄ H ₉ ) ₂ Sn (SCH ₂ COOC ₈ H ₁₇ -iso) ₂ ,
(nC ₈ H ₁₇ ) ₂ Sn (SCH ₂ COOC ₈ H ₁₇ -iso) ₂ , (nC ₈ H ₁₇ ) ₂ Sn (SCH
₂ COOC ₈ H ₁₇ -n) ₂ , (nC ₄ H ₉ ) ₂ SnS.

[0074]

Embedded image (nC ₄ H ₉ ) ₂ Sn (acac) ₂ , (nC ₈ H ₁₇ ) ₂ Sn (acac)
₂ , (nC ₄ H ₉ ) ₂ (C ₈ H ₁₇ O) Sn (acac), (nC ₄ H ₉ ) ₂ (C ₈ H ₁₇ O) S
n (e-acac).

[0075]

Embedded image (nC ₄ H ₉ ) ₂ (CH ₃ COO) SnOSn (OCOCH ₃ ) (nC ₄ H ₉ )
₂ , (nC ₄ H ₉ ) ₂ (CH ₃ O) SnOSn (OCH ₃ ) (nC ₄ H ₉ ) ₂ .

In the curable composition of the present invention, a compound having an air oxidation-curable unsaturated group in the molecule (hereinafter referred to as an unsaturated group-containing compound) may be used as a surface modifier. Examples of the unsaturated group-containing compound include drying oils such as tung oil, linseed oil, and dehydrated castor oil, and modified and polymer forms thereof. Tung oil is particularly preferred.

These unsaturated group-containing compounds may be used alone or in combination of two or more.

The unsaturated group-containing compound is used in an amount of 0.1 to 20 parts, especially 1 to 100 parts by weight of the organic polymer (A).
10 parts are preferred.

Other dehydrating agents include alkyl orthoformates, hydrolyzable organic silicon compounds such as vinyltrimethoxysilane and tetraethylsilicate, and hydrolyzable organic titanium compounds. Adhesion-imparting agents include phenol resins and epoxy resins. Known silane coupling agents and denatured products thereof, various anti-aging agents, ultraviolet absorbers, light stabilizers and the like can be used.

The curable composition of the present invention cures at room temperature in the presence of moisture and can be used particularly for elastic sealants and adhesives.

[0081]

The present invention will be described below with reference to Examples (Examples 1 to 4) and Comparative Examples (Examples 5 to 8).

[Production Example of Polyether P1] Using glycerin as an initiator, propylene oxide was polymerized with a zinc hexacyanocobaltate catalyst to obtain polyoxypropylene triol. After adding a methanol solution of sodium methylate, methanol was distilled off, and the terminal of polyoxypropylene triol was converted to sodium alkoxide. Allyl chloride was added and reacted to convert the terminal into an allyloxy group.

After purifying the allyl-terminated polyoxypropylene (metal ionic impurities: 10 ppm or less), methyldimethoxysilane was reacted in the presence of a platinum catalyst to convert the allyl group to a methyldimethoxysilylpropyl group.
Polyether P1 having a hydroxyl value-converted molecular weight of 17000 was obtained.

[Production Example of Trimethylsilyloxy Group-Containing Compound] One mole of the polyhydric alcohol shown in Table 1 was charged into an eggplant-shaped flask, heated to 70 ° C., and then heated to 1,1,1,3,3.
A mixture of pmol 3,3-hexamethyldisilazane and qmol trimethylchlorosilane was added dropwise. After the dropwise addition, a heating reaction was performed for 4 hours while maintaining the temperature at 70 ° C. After cooling to room temperature,
The reaction was stirred and dispersed in a 1% by weight aqueous sodium carbonate solution, and the operation of discarding the aqueous layer with a separating funnel was repeated to remove ammonium salts. Magnesium sulfate was added to the organic layer, and after dehydration, magnesium sulfate was removed to obtain compounds (compounds a to d) in which r% of the hydroxyl groups of the starting polyhydric alcohol contained trimethylsilyloxy groups. Table 1 shows the values of p, q, and r.

[0085]

[Table 1]

Examples 1 to 8 1.5 parts of a silicon compound, 5 parts of tung oil, and 120 parts of colloidal calcium carbonate shown in Table 2 with respect to 100 parts by weight of polyether P1
Parts, calcium bicarbonate 20 parts, dioctyl phthalate 30
, Sansocizer E-PS (Shin Nippon Rika Co., Ltd.)
20 parts, 3 parts of hydrogenated castor oil, 5 parts of titanium oxide, 1 part of a benzotriazole-based ultraviolet absorber, 1 part of a hindered amine-based light stabilizer and 0.5 part of a hindered phenol-based antioxidant, are added to a three-roll mill. And kneaded. This is 2
A mixture consisting of 3 parts of tin ethylhexanoate and 1 part of laurylamine was added and uniformly mixed to obtain a composition.

Using this composition, JIS A5758
An H-type specimen was prepared according to the method described in Example 2, and the tensile properties [50% modulus (M ₅₀ , unit: kg / cm ² )] were measured.

On the other hand, the same composition was placed in a polyethylene mold having a depth of 2 cm, cured at 20 ° C. and a humidity of 65% for 6 hours, removed from the mold, and evaluated for the deep part curability. All of the curing up to the bottom was evaluated as ○, and the uncured portion remained as X.

When the surface tackiness after curing was evaluated by touching with a finger, all of them were almost the same as those in the case where no compound containing a trimethylsilyloxy group was added (Example 8).

Table 2 shows the results.

[0091]

[Table 2]

[0092]

The curable composition of the present invention has an effect of providing a curable composition characterized by excellent surface low tackiness even in a low modulus region and further excellent in deep curability.

Claims (4)

[Claims] 1. An organic polymer (A) having a molecular weight of 2,000 or more having one or more hydrolyzable silicon groups capable of being crosslinked by hydrolysis in a molecule, and having 2.1 or more trimethylsilyloxy groups in a molecule. A curable composition comprising a compound (B) having a molecular weight of 1,000 or less. 2. The curable composition according to claim 1, wherein the hydrolyzable silicon group is a group represented by the formula 1. ## STR1 ## Among -SiX _a R ¹ _3-a ··· Formula 1 Formula 1, R ¹ is 1 substituted or unsubstituted 1 to 20 carbon atoms
A monovalent hydrocarbon group, X is a hydroxyl group or a monovalent hydrolyzable group, and a is an integer of 1 to 3. 3. The curable composition according to claim 1, wherein the total amount of ionic impurities in the organic polymer (A) is 50 ppm or less. 4. The curing method according to claim 1, wherein the organic polymer (A) is a derivative of a polyoxyalkylene polymer obtained by polymerizing a cyclic ether with an initiator using a double metal cyanide complex as a catalyst. Composition.