JPH10292102A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable resin composition excellent in viscosity, thixotropic properties and transparency, by including a specified oxyalkylene polymer, an organohydrogenpolysiloxane, a hydrosilylating catalyst and specified silica fine powder. SOLUTION: This resin composition comprises (A) an oxyalkylene polymer containing at least one alkenyl group of the formula H2 C=C(R<4> ) (R<4> is H or methyl) in one molecule and composed of CH2 CH(CH3 )O, etc., as a main monomer unit, (B) an organohydrogenpolysiloxane containing at least two groups preferably of the formula (R<1> is H or methyl; R<2> is a 1-4C alkyl, etc.; (a) is 0-5) in the molecule and having >=600 molecular weight, (C) a hydrosilylating catalyst such as chloroplatinic acid and (D) silica fine powder subjected to surface treatment, for example, which an organopolysiloxane of the formula XR2 Si-O(SiR2 O)n -SiR2 X (X is an alkyl, hydroxyl, etc.; R is an alkyl, phenyl, etc.; (n) is 1-500).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curable composition having excellent thixotropy.

[0002]

2. Description of the Related Art Various types of curable compositions have been developed which cure to form rubber-like substances. Among these, a curable composition comprising a main agent containing an oxyalkylene polymer having one or more alkenyl groups in a molecule and a curing agent containing a compound having a hydrosilyl group has a rapid curing property and a deep curing property. It is known as an excellent curable composition. When using a curable composition, an anti-sagging agent is often used to prevent the uncured composition from dripping. The anti-sagging agent enhances the workability by preventing the uncured composition from dripping when the composition is used as a sealant or an adhesive by increasing the viscosity and thixotropy of the composition. Organic compounds such as polyamide wax and hydrogenated castor oil have been used as anti-sagging agents. However, these compounds have a low dispersibility in the curable polymer and the composition is opaque. There is a problem that things cannot be obtained. Also, silica is known as a transparent filler used in the curable composition. Among the silicas, hydrophilic fine powdered silica having an inorganic silanol group on the surface manufactured by a dry method can easily obtain a transparent composition by mixing at room temperature, and also has an effect as an anti-sagging agent. But,
There is a problem that the viscosity of the composition considered to be due to the reactivity of the surface silanol groups fluctuates, and a composition having a predetermined viscosity cannot be obtained. Further, there has been known a hydrophobic fine powder silica which has been made hydrophobic by treating a silica surface with a silane compound (silylating agent) such as hexamethylsilazane or dimethyldichlorosilane. However, these silicas have small thickening and thixotropic properties, and their effects as anti-sagging agents are small.

[0003]

An object of the present invention is to provide a transparent curable composition which has high viscosity and thixotropic properties, is excellent in sagging prevention effect, and is transparent.

[0004]

Means for Solving the Problems The present inventor has found that the above problems can be solved by using silica fine powder surface-treated with an organopolysiloxane as a thixotropic agent, and has completed the present invention. That is, the present invention relates to (a) an oxyalkylene polymer having at least one alkenyl group in one molecule, (b) an organohydrogenpolysiloxane,
The present invention relates to a curable composition containing (c) a hydrosilylation catalyst, and (d) silica fine powder surface-treated with an organopolysiloxane.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The (a) oxyalkylene polymer containing at least one alkenyl group in one molecule used in the present invention has a repeating unit represented by the general formula (2). —R ³ —O— (2) (wherein, R ³ is a divalent alkylene group)

[0006] In the general formula (2), R ³ is
Fourteen, even two to four, linear or branched alkylene groups are preferred. Specific examples of the repeating unit represented by the general formula _{(2), -CH 2 O -} , - CH 2 CH 2 O
_{-, - CH 2 CH (CH} 3) O -, - CH 2 CH (C
_{2 H 5) O -, -} CH 2 C (CH 3) 2 O -, - CH 2 CH 2
CH ₂ CH ₂ O— and the like.

The main chain skeleton of the oxyalkylene polymer is 1
It may be composed of only types of repeating units, or may be composed of two or more types of repeating units. In particular, -CH ₂ C
A polymer having H (CH ₃ ) O— as a main monomer unit is preferred. Further, the main chain of the polymer may contain a repeating unit other than the oxyalkylene group. In this case, the total of the oxyalkylene units in the polymer is 80% by weight or more,
In particular, 90% by weight or more is preferable. The polymer of the component (a) may be a linear polymer or a branched polymer,
Its molecular weight is about 500 to 50,000, especially
00 to 30,000 is preferred. The alkenyl group in the component (a) is not particularly limited, but an alkenyl group represented by the following formula (3) is preferably used. H ₂ C ＝ C (R ⁴ ) — (3) (wherein R ⁴ is hydrogen or a methyl group) There is no particular limitation on the manner in which the alkenyl group is bonded to the oxyalkylene polymer. Direct bond, ether bond, ester bond, carbonate bond, urethane bond, and urea bond.

As a specific example of the polymer of the component (a), formula (4): {H ₂ C = C (R ⁵ ) —R ⁶ —O} _a R ⁷ (4) (where R ⁵ is hydrogen Or a methyl group, R ⁶ has 1 to 20 carbon atoms
Wherein R ⁷ is an oxyalkylene polymer residue, and a is a positive integer. ). Specifically, R ⁶ represents —CH ₂ —, —CH ₂ C
H ₂ —, —CH ₂ CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) C
H ₂ —, —CH ₂ CH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ OC
H ₂ CH ₂ — or —CH ₂ CH ₂ OCH ₂ CH ₂ CH ₂ —
And the like. From the ease of synthesis, -C
H ₂ -is preferred.

[0009] (a) expression as another specific example of the components of the polymer _{(5): {H 2 C} = C (R 5) R 6 O 2 C} a R 7 (5) ( wherein, R ⁵ , R ⁶ , R ⁷ and a are the same as those described above).

Also, a polymer represented by the following formula (6): {H ₂ C = C (R ⁵ )} _a R ⁷ (6) (wherein R ⁵ , R ⁷ and a are the same as above) Are also mentioned. Further, the following formula (7): {H ₂ C = C (R ⁵ ) R ⁶ O ₂ CO} _a R ⁷ (7) (where R ⁵ , R ⁶ , R ⁷ and a are the same as above) The polymer which has a carbonate bond shown by these is also mentioned.

Various methods can be used to introduce an alkenyl group into the oxyalkylene polymer. For example, it can be introduced by copolymerization of a monomer having an alkenyl group such as allyl glycidyl ether and an oxyalkylene monomer. Further, by reacting an oxyalkylene polymer having a functional group such as a hydroxyl group or an alkoxide group on a main chain or a side chain thereof with an organic compound having a functional group having a reactivity with these functional groups and an alkenyl group, Groups can be introduced into the main chain or side chains. In particular, when the alkenyl group is present at the polymer chain terminal, the effective network chain length in the cured product is increased, and the curable composition is excellent in mechanical properties.

Examples of the organic compound having a functional group reactive with another functional group and an alkenyl group include those having 3 to 3 carbon atoms such as acrylic acid, methacrylic acid, vinyl acetate, acrylic chloride and acrylic bromide. 20
Unsaturated fatty acids, acid halides, acid anhydrides, allyl chloroformate, allyl chloride, allyl bromide, vinyl (chloromethyl) benzene, allyl (chloromethyl) benzene, allyl (bromomethyl) benzene, allyl (chloromethyl) ether, Allyl (chloromethoxy) benzene, 1-butenyl (chloromethyl) ether, 1-hexenyl (chloromethoxy) benzene, allyloxy (chloromethyl) benzene and the like can be mentioned. It is preferable that at least one, preferably 1.1 to 5 alkenyl groups be present in one molecule of the polymer. If the number of alkenyl groups contained in the molecule is less than 1, the curability will be insufficient, and if it is too large, the network structure will be too dense and may not exhibit good mechanical properties.

As the organohydrogenpolysiloxane of the component (b) of the present invention, any of those having a hydrosilyl group can be used. In particular, an organohydrogenpolysiloxane modified with an organic component is also included in the component (b) of the present invention. The fact that excellent compatibility and excellent cured product are obtained means that a group represented by the following formula (1) has at least 2
An organohydrogenpolysiloxane having a molecular weight of at least 600 and having at least one is preferred.

[0014]

Embedded image (Wherein, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a methoxy group, an ethoxy group, an acetoxy group, a halogen or a nitrile group,
^{When 2} is two or more, they may be the same or different. a is 0 or an integer of 1 to 5. )

When an organohydrogenpolysiloxane having at least two groups represented by the structural formula (1) per molecule is used, the compatibility with the oxyalkylene polymer as the component (a) is remarkably improved, In addition, the physical properties of the obtained cured product are improved. If the molecular weight of the organohydrogenpolysiloxane is too small, workability such as evaporation during curing may be deteriorated, and a good cured product may not be obtained. Therefore, the molecular weight is preferably 600 or more. A preferred specific example of the component (b) is an organohydrogenpolysiloxane represented by the following structural formula (8).

[0016]

Embedded image (Wherein, R ¹ , R ² , and a are the same as above, R ⁸ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group;
⁹ represents an alkyl group having 1 to 6 carbon atoms or a phenyl group,
R ¹⁰ represents an alkyl group having 1 to 18 carbon atoms or a phenyl group, l, m and n are 2 ≦ l, 2 ≦ m, 0 ≦ n ≦ 50,
It is a positive integer satisfying the condition of 8 ≦ l + m + n ≦ 100. )

Examples of R ⁸ include -H, -CH ₃ , -CH
_{2 CH 3, -CH 2 CH 2} CH 3, -CH (CH 3) 2, -C
_{H 2 CH 2 CH 2 CH 3} , -C (CH 3) 3, -CH 2 CH 2 C
_{H 2 CH 2 CH 3, -CH} 2 CH 2 CH 2 CH 2 CH 2 CH 3,
And a phenyl group, but -CH ₃ is preferred from the viewpoint of ease of production.

Specific examples of R ⁹ include —CH ₃ , —CH _{2
CH 3, -CH 2 CH 2 CH} 3, -CH (CH 3) 2, -CH
_{2 CH 2 CH 2 CH 3,} -C (CH 3) 3, -CH 2 CH 2 CH
_{2 CH 2 CH 3, -CH 2} CH 2 CH 2 CH 2 CH 2 CH 3, and the like can be mentioned phenyl group, preferably -CH ₃ ease of manufacture.

Specific examples of R ¹⁰ include —CH ₃ , —CH _{2
CH 3, -CH 2 CH 2 CH} 3, -CH (CH 3) 2, -CH
_{2 CH 2 CH 2 CH 3,} -C (CH 3) 3, -CH 2 CH 2 CH
_{2 CH 2 CH 3, -CH 2} CH 2 CH 2 CH 2 CH 2 CH 3, -
(CH ₂ ) ₆ CH ₃ , — (CH ₂ ) ₇ CH ₃ , — (CH ₂ ) ₈ C
H ₃ , — (CH ₂ ) ₉ CH ₃ , and — (CH ₂ ) ₁₇ CH ₃ can be exemplified.

The component (b) is represented by the following structural formula (9) from the viewpoints of easy availability of raw materials, easy production, good workability such as low viscosity, and physical properties of the obtained cured product. The indicated organohydrogenpolysiloxanes are more preferred.

[0021]

Embedded image (Wherein, R ¹ is the same as above, l and m are 2 ≦ l, 2 ≦
m and a positive integer satisfying the condition of 8 ≦ l + m ≦ 100. )

When the organohydrogenpolysiloxane represented by the structural formula (8) is used, l + m + n is preferably 100 or less from the viewpoint of easiness of production, workability, and physical properties of the cured product. When the organohydrogenpolysiloxane represented by the structural formula (9) is used, l + m is preferably 100 or less, and more preferably 60 or less.

In the present invention, a compound having a hydrosilyl group in the molecule may be used in addition to the component (b). The hydrosilyl group-containing compound that can be used in combination is not particularly limited, but various compounds ranging from low molecular weight compounds to polymers can be used.

Component (b) should be used in such an amount that the hydrosilyl group (Si-H group) is 0.6 to 3.0 per alkenyl group of component (a). Preferably, 0.8 to 1.5 are more preferable. If the amount of the component (b) is too small, the crosslinking point becomes insufficient, so that a good cured product may not be obtained. On the other hand, if the amount of the component (b) is too large, unreacted hydrosilyl groups may remain and adversely affect the physical properties of the cured product, which is not preferable.

The hydrosilylation catalyst which is the component (c) of the present invention is well known and can be used.
Specific examples include a simple substance of platinum; a substance in which solid platinum is supported on a simple substance such as alumina, silica and carbon black; chloroplatinic acid; complexes of chloroplatinic acid with alcohols, aldehydes, ketones and the like; platinum-olefin complexes For example, Pt (C
H ₂ ＣＨCH ₂ ) ₂ (PPh ₃ ) ₂ , Pt (CH ₂ 2CH ₂ ) C
l ₂ }; platinum-vinylsiloxane complex {for example, Pt _n (V
iMe ₂ SiOSiMe ₂ Vi) _m , Pt [(MeViSi
O) ₄ ] _m }; platinum-phosphine complex {eg, Pt (PP
_{h 3) 4, Pt (PBu} 3) 4}; platinum - phosphite complex {e.g. _{Pt [P (OPh) 3]} 4, Pt [P (OB
u) ₃ ] ₄ } (where Me is a methyl group, Bu is a butyl group,
Vi represents a vinyl group, Ph represents a phenyl group, and m and n each represent an integer.); Dicarbonyldichloroplatinum; and Ashby U.S. Pat. Nos. 3,159,601 and 3,159. Platinum-hydrocarbon complexes described in U.S. Patent No. 3,220,972 to Lamoreaux, and platinum alcoholate catalysts described in Lamoreaux U.S. Patent No. 3,220,972. Further, the platinum chloride-olefin composite described in Modic U.S. Pat. No. 3,516,946 can be used in the present invention.

Examples of catalysts other than platinum compounds include:
RhCl (PPh ₃ ) ₃ , RhCl ₃ , Rh / Al ₂ O ₃ ,
RuCl ₃ , IrCl ₃ , FeCl ₃ , AlCl ₃ , PdC
_{l 2 · 2H 2 O, NiCl} 2, TiCl 4 , and the like.
(Ph represents a phenyl group). These catalysts may be used alone or in combination of two or more. From the viewpoint of catalytic activity, chloroplatinic acid, a platinum-olefin complex, a platinum-acetylacetonate complex, and a platinum-vinylsiloxane complex are preferred.

The amount of the hydrosilylation catalyst used as the component (c) is preferably 1 × 10 ^-1 to 1 × 10 ^-8 mol per 1 mol of the alkenyl group in the component (a). . Preferably, it is used in the range of 1 × 10 ⁻³ to 1 × 10 ⁻⁶ mol. The amount of the hydrosilylation catalyst used is 1 × 10
^{If the} amount is less than ^-8 mol, the curing may not proceed sufficiently, which is not preferable. Further, a hydrosilylation catalyst is generally expensive and corrosive, and a large amount of hydrogen gas may be generated to foam a cured product.
It is better not to use more than ^-1 mol.

Further, the catalytic activity of the component (c) is adjusted,
In order to improve the storage stability of the composition (prolong the pot life), a storage stability improver can be added as needed. As the storage stability improver, any kind of a usual stabilizer known as a storage stability improver for a curable composition by a hydrosilylation reaction may be used. For example, a compound having an aliphatic unsaturated bond,
Organic phosphorus compounds, organic sulfur compounds, nitrogen-containing compounds, tin compounds, organic peroxides and the like can be suitably used.

Specifically, 2-methyl-3-butyne-2
-Ol, benzothiazole, thiazole, dimethylmalate, 2-pentenenitrile, 2,3-dichloropropene and the like. In particular, 2-methyl-3-butyne-2 is considered to satisfy both pot life and fast-curing properties.
-All, thiazole, benzothiazole, dimethylmalate are preferred, but not limited to.

The amount of the storage stability improver can be arbitrarily selected as long as the component (a) and the component (b) are uniformly dispersed. ,
It is preferably used in the range of 1 × 10 ^-6 to 1 × 10 ^-1 mol. If the amount used is less than 1 × 10 ⁻⁶ , the storage stability of the component (b) may not be sufficiently improved,
^If it exceeds ^-1 mol, curing may be inhibited. These storage stability improvers may be used alone or in combination of two or more. Specific examples of the components (a), (b) and (c) are also disclosed in JP-A-7-300555.

The silica used for the component (d) of the present invention is preferably a so-called fumed silica produced by flame hydrolysis of a silicon halide compound. Examples of commercially available fine silica powder are as follows. It is commercially available under a trade name such as AEROSIL 5
0, 130, 200, 300, 380, OX50, TT
600, MOX80, MOX170 (Nippon Aerosil Co., Ltd.), REOLOSILQS-10, QS-20, Q
S-102, QS-30, QS-40 (all from Tokuyama), Cabosil M-5, MS-7, MS-7
5, HS-5, EH-5 (above CABOT), Wac
ker HDK N20, T30, T40 (WAC
KER CHEMIE).

As the organopolysiloxane which is a treating agent for the silica fine powder, any polymer known as an organopolysiloxane can be used. The viscosity of the organopolysiloxane ranges from 2 cSt to 1,000.
0 cSt (25 ° C.), particularly preferably 5 cSt to 500 cSt, more preferably 5 cSt to 100 cSt. If it is less than 2 cSt, it may be easy to volatilize and heat treatment may not be easy. If it is more than 1,000 cSt, the viscosity may be so high that it may not be easy to uniformly treat the silica.

As a specific example of the organopolysiloxane, an organopolysiloxane represented by the following general formula can be given. XR ₂ Si—O (SiR ₂ O) _n —SiR ₂ X (where X is a group selected from an alkyl group, a hydroxyl group and an alkoxy group, and R is an alkyl group, a phenyl group, a polyether chain-substituted alkyl group, etc.) A group having a polyether chain,
Represents a group selected from an epoxy-substituted alkyl group and a carbinol group, wherein R may be the same or different;
Represents an integer of 1 to 500. In the above formula, when R or X is an alkyl group, examples thereof include a methyl group and an ethyl group.

Examples of the organopolysiloxane include those commercially available under the following trade names. KF96
L, KF96 (dimethyl type), KF99 (methyl hydrogen type), KF50 (methylphenyl type), KF410 (alkyl modified type), KF3
51, KF351A, KF353, KF355, KF6
15, KF618, KF945, KF907, X-22-6008, KF6011 (above polyether modified type), KF851 (alcohol modified type), X-22-
819 (fluorine-modified type), KF910 (higher fatty acid ester-modified type), X-22-3500 (carnauba-modified type), KF3935 (amide-modified type), KF
393 (amino-modified) KF105 (epoxy-modified), X-22-162A (carboxyl-modified), K
F6001 (Carbinol-modified type), X-22-16
4B, X-22-5002 (above methacryl-modified type), X-22-3667, X-22-3939A (polyether group and heterofunctional group-modified type), etc. (all Shin-Etsu Chemical Co., Ltd.), SH200, SH550, SH1107 , S
H8411, SH8416, SH8400, OFS54
6, 818B, etc. (above, Dow Corning Toray Silicone), TSF451, TSF431, TSF483,
TSF4420, TSF4730, etc. (Toshiba Silicone Co., Ltd.).

In the above formula, when R is a modified organopolysiloxane such as a group having a polyether chain, the position of such an organic group may be either the side chain or the terminal of the polysiloxane. Among the organopolysiloxanes, a polyether-modified polysiloxane in which a group having a polyether chain is bonded to a side chain or a terminal is particularly preferable because the surface-treated silica is particularly excellent in viscosity and thixotropy.

As an example of the method for producing these surface-treated silicas, a silica powder (for example, AEROSIL 200) is placed in a closed Henschel mixer, and 3 to 40 parts by weight of an organopolysiloxane (for example, KF
96-50 cSt) is added dropwise while stirring at high speed. For uniform treatment, the organopolysiloxane is preferably diluted with a solvent such as hexane.
After dropping, by heating to 100 to 400 ° C,
The organopolysiloxane is chemically bonded to the silica surface. If the treatment amount of the organopolysiloxane is 3 parts by weight or less, the silica surface may not be sufficiently covered, so that silanol groups remain, which is not preferable. Also, 40
It is not economical to use more than parts by weight.

The composition of the present invention can contain various plasticizers as required. If the amount of the plasticizer used is in the range of 0.1 to 150 parts by weight based on 100 parts by weight of the oxyalkylene polymer as the component (a), preferable results can be obtained. If the amount exceeds 150 parts by weight, the amount of the liquid component increases, which is not preferable.

As the plasticizer, dioctyl phthalate,
Phthalates such as diisodecyl phthalate, dibutyl phthalate and butyl benzyl phthalate; epoxy plasticizers such as epoxidized soybean oil, epoxidized linseed oil and benzyl epoxy stearate; polyesters of dibasic acid and dihydric alcohol Polyethers such as polypropylene glycol and derivatives thereof; Polystyrenes such as poly-α-methylstyrene and polystyrene; Polybutadiene, butadiene-acrylonitrile copolymer, polychloroprene, polyisoprene, polybutene, chlorinated Plasticizers such as paraffins can be used alone or in the form of a mixture of two or more.

Further, the composition of the present invention can contain various additives such as a dehydrating agent, a physical property modifier, a filler and an antioxidant, if necessary.

The curable composition of the present invention can be cured at room temperature, but can be quickly cured by heating it to 80 ° C. or higher. In addition, since the curing is carried out by using an addition reaction, a cured product having small shrinkage and excellent in deep-part curability can be obtained.

The curable composition of the present invention can be applied to various uses. For example, molded articles,
Adhesives, pressure-sensitive adhesives, paints, paint waterproofing agents, sealing agents, foam sealing agents, electric / electronic potting agents, films and the like. Hereinafter, the present invention will be specifically described with reference to examples.

[0042]

【Example】

Synthesis Example 1 100 parts by weight of silica fine powder (AEROSIL 200, manufactured by Nippon Aerosil Co., Ltd.) produced by flame hydrolysis of a silicon halide compound was placed in a closed Henschel mixer, stirred while purging with nitrogen, and treated with a viscosity of 50 cSt as a treating agent. Of methyl-terminated dimethylpolysiloxane (K
F96, manufactured by Shin-Etsu Chemical Co., Ltd.) was spray-mixed, and then heated and stirred at 250 ° C. for 30 minutes to obtain surface dimethylpolysiloxane-treated silica (A).

Synthesis Example 2 A polysiloxane-treated silica (B) was obtained in the same manner as in Synthesis Example 1 except that the polysiloxane used as the treating agent was polyether-modified silicone oil KF618 (manufactured by Shin-Etsu Chemical Co., Ltd.).

Synthesis Example 3 A polysiloxane-treated silica (C) was obtained in the same manner as in Synthesis Example 1, except that the polysiloxane used as the treating agent was polyether-modified silicone oil KF351A (manufactured by Shin-Etsu Chemical Co., Ltd.).

Synthesis Example 4 A polysiloxane-treated silica (D) was obtained in the same manner as in Synthesis Example 1, except that the polysiloxane used as the treating agent was epoxy-modified silicone oil 818B (manufactured by Dow Corning Toray Silicone Co., Ltd.). Was.

Synthesis Example 5 Polysiloxane-treated silica (E) was treated in the same manner as in Synthesis Example 1 except that the polysiloxane as a treating agent was a double-ended hydroxyl group-modified silicone oil OFS546 (manufactured by Dow Corning Toray Silicone Co., Ltd.). I got

Example 1 A number average molecular weight having an allyl ether group at a terminal of 8,000
0 parts by weight of 100 parts by weight of the propylene oxide polymer of No. 0 as a sagging inhibitor, 3 parts by weight of silica (A) treated with surface dimethylpolysiloxane of Synthesis Example 1 as powder, and 50 parts by weight of DOP (dioctyl phthalate) as a plasticizer , Surface treated colloidal calcium carbonate 100 as filler
Parts by weight and 35 parts by weight of heavy calcium carbonate were added. After kneading with a spatula in advance, the mixture was passed three times through a small three paint roll to obtain a composition. The obtained composition was placed in a glass container (K-
5) and stored at 23 ° C. for 15 days. The viscosity and thixotropic property were measured at 23 ° C. using a BS viscometer. The results are shown in Table 1. The viscosity indicates a viscosity value at 2 rpm. The viscosity ratio was determined from the ratio of the viscosity at 2 rpm to the viscosity at 10 rpm. The higher the viscosity ratio, the better the thixotropy. Also, the greater the viscosity and the viscosity ratio, the greater the sagging prevention effect.

[0048]

[Table 1] As is clear from Table 1, it is found that the viscosity and the viscosity ratio are larger when the silica surface-treated with the organopolysiloxane is used than when other silica is used or when no silica is used. The composition of Example 1 does not contain (b) an organohydrogenpolysiloxane as a curing agent or (c) a hydrosilylation catalyst as a curing catalyst. However, a curing agent or a curing catalyst is usually used in a small amount relative to the main agent. Therefore, even when a curing agent or a curing catalyst is added to the composition of Example 1, the viscosity and viscosity ratio of the composition of Example 1 are similar to those of the composition of Example 1. This applies to other embodiments of the present invention.

Example 2 The same operation as in Example 1 was carried out except that RY200S (manufactured by Nippon Aerosil Co., Ltd.), a commercially available silica product treated with dimethylpolysiloxane on the surface, was used as an anti-sagging agent.

Comparative Examples 1 and 2 Hydrophobically treated silica R treated with surface silane was used as an anti-sagging agent.
972, and the same operation as in Example 1 was performed except that RX200 (manufactured by Nippon Aerosil Co., Ltd.) was used as it was.

Comparative Example 3 The same operation as in Example 1 was performed except that the anti-sagging agent was not used.

Example 3 Number average molecular weight of 8,0 containing allyl ether group at terminal
100 parts by weight of the propylene oxide polymer of No. 00 and 3 parts by weight of the surface dimethylpolysiloxane-treated silica (A) of Synthesis Example 1 as an anti-sagging agent.
The composition was passed twice through three small paint rolls to obtain a composition. The obtained composition was placed in a glass container having a diameter of 3.6 cm (K-8).
And stored at 23 ° C. for 7 days. BH at 23 ° C
The viscosity and thixotropy were measured using a mold viscometer. The results are shown in Tables 2 and 3. The transparency was determined by visually observing a sample placed in a 3.6 cm diameter glass container (K-8).

Example 4 The same operation as in Example 3 was carried out except that RY200S (manufactured by Nippon Aerosil Co., Ltd.), a commercially available silica product treated with dimethylpolysiloxane on the surface, was used as the anti-sagging agent.

Example 5 The same operation as in Example 3 was carried out except that the surface polyether-modified silicone-treated silica (B) of Synthesis Example 2 was used as a sagging inhibitor. Example 6 The same operation as in Example 3 was performed except that the surface polyether-modified silicone-treated silica (C) of Synthesis Example 3 was used as a sagging inhibitor.

Example 7 The same operation as in Example 3 was carried out except that the surface-epoxy-modified silicone-treated silica (D) of Synthesis Example 4 was used as an anti-sagging agent.

Example 8 The same operation as in Example 3 was carried out except that the silica (E) treated with a hydroxyl group modified at both ends of the surface of Synthesis Example 5 was used as an anti-sagging agent.

Comparative Examples 4 to 7 Hydrophobally treated silica R treated with surface silane as anti-sagging agent
972, RX200 (manufactured by Nippon Aerosil Co., Ltd.), hydrogenated castor oil, and aliphatic amide wax were used as they were in Example 3. Comparative Example 8 The same operation as in Example 3 was performed except that the anti-sagging agent was not used.

[0058]

[Table 2]

[0059]

[Table 3]

As is clear from Tables 2 and 3, the use of silica surface-treated with organopolysiloxane has a higher viscosity and viscosity ratio than those using other silica or no silica. Recognize. It is also found that the use of silica surface-treated with a polyether-modified organopolysiloxane particularly increases the viscosity and the viscosity ratio.

[0061]

As described above, the curable composition of the present invention is excellent in viscosity, thixotropy, and transparency.

Claims (6)

[Claims] 1. A surface comprising (a) an oxyalkylene polymer having at least one alkenyl group in one molecule, (b) an organohydrogenpolysiloxane, (c) a hydrosilylation catalyst, and (d) an organopolysiloxane. A curable composition containing the treated silica fine powder. Wherein a silica fine silica powder produced by flame hydrolysis of silicon halide, characterized in that the specific surface area of 20m ² / g~400m ² / g by a nitrogen adsorption method (BET method) The curable composition according to claim 1, wherein 3. The curable composition according to claim 1, wherein the organopolysiloxane is a polymer represented by the following general formula. XR ₂ Si—O (SiR ₂ O) _n —SiR ₂ X (where X is a group selected from an alkyl group, a hydroxyl group and an alkoxy group, R is an alkyl group, a phenyl group, a group having a polyether chain, epoxy substitution Represents a group selected from an alkyl group and a carbinol group, R may be the same or different, and n represents an integer of 1 to 500.) 4. The curable composition according to claim 3, wherein X is a group having a polyether chain. 5. The curable composition according to claim 1, wherein the treatment amount of the organopolysiloxane is 3 to 40 parts by weight based on 100 parts by weight of the silica. 6. The organohydrogenpolysiloxane according to claim 1, wherein the organohydrogenpolysiloxane is an organohydrogenpolysiloxane having at least two groups represented by the general formula (1) in a molecule and having a molecular weight of 600 or more. Cured composition. Embedded image (Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a methoxy group, an ethoxy group, an acetoxy group, a halogen or a nitrile group,
When there are two or more R ² , they may be the same or different. a is 0 or an integer of 1 to 5. )