JP2002047418A - Room temperature curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a room temperature curable composition which has solved the problem that pollutants such as dust and an exhaust gas easily adhere and gives cured products having excellent stain resistance in cured products of a sealing medium, and the like comprising a polymeric plasticizer. SOLUTION: This room temperature curable composition comprises (A) 100 pts.wt. organic polymer having at least one group which contains a silicon atom bonded to a hydroxyl group or a hydrolysable group and can crosslink by forming a siloxane bond and (B) 0.1-100 pts.wt. titanium oxide coated with apatite. preferably, the coating thickness in the component (B) is 0.1-5 nm, and further the particle diameter of component (B) is 20-40 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room-temperature curable composition comprising a polymer which cures into a rubbery state by reacting with moisture in the atmosphere, and more particularly to a sealing material excellent in stain resistance. About.

[0002]

2. Description of the Related Art As a polymer which reacts with moisture in the air to cure into a rubbery state, an organic polymer having a molecular weight of 300 to 15,000 having at least one hydrolyzable group per polymer molecule can be used. For example, Japanese Patent Application Laid-Open No. 55-3187
No. 4 describes a curable composition in which a polymer having a hydrolyzable group and having the above-mentioned molecular weight is blended with a polymer plasticizer such as polyester or polypropylene glycol. However, when a sealing material containing such a high-molecular plasticizer is used for joints on the outer wall, the plasticizer bleeds out to the surface of the sealing material over time, and contaminants such as dust and exhaust gas adhere. In addition, there is a problem that it is easily stained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a room temperature curable composition which solves the above-mentioned problems of the prior art and gives a cured product having excellent stain resistance.

[0004]

The room temperature curable composition according to claim 1 (hereinafter referred to as the present invention 1) comprises (A) a silicon atom bonded to a hydroxyl group or a hydrolyzable group to form a siloxane bond. It is characterized by comprising 100 parts by weight of an organic polymer having at least one functional group capable of being crosslinked by the above process, and (B) 0.1 to 100 parts by weight of titanium oxide coated with apatite. The room-temperature curable composition according to claim 2 (hereinafter referred to as the present invention 2) has a titanium oxide coated with apatite according to claim 1 having a coating thickness of 0.1 to 0.1.
The thickness is 5 nm. A room-temperature curable composition according to claim 3 (hereinafter referred to as the present invention 3) is characterized in that the particle diameter of the titanium oxide coated with apatite according to claim 1 or 2 is 20 to 40 nm.

Hereinafter, the present invention will be described in detail. Invention 1
A typical example of the organic polymer (A) used in the above is a polymer whose main chain is essentially polyoxyalkylene and has a crosslinkable hydrolyzable silyl group at a terminal, and is usually called a modified silicone polymer. .

Examples of modified silicone polymers include, for example, polyoxyalkylenes having an allyl group at the terminal
In the presence of a Group II transition metal,

[0007]

Embedded image (Wherein, R is a group composed of a monovalent hydrocarbon group and a halogenated monovalent hydrocarbon group, a is an integer of 0, 1 or 2, and X is selected from a halogen atom, an alkoxy group, an acyloxy group and a ketoximate group. And a silicon hydride compound represented by the following formula:

Examples of the polyoxyalkylene which is the main chain of the polymer include polyoxyethylene, polyoxypropylene, polyoxybutylene and the like. At present, polyoxypropylene is generally commercially available.

Examples of the crosslinkable hydrolyzable silyl group include a methoxysilyl group and an ethoxysilyl group, and a methoxysilyl group is preferably used.

The modified silicone polymer preferably has a molecular weight of 4,000 to 30,000, and particularly has a molecular weight of 10,000 to 30,000 and a molecular weight distribution (Mw /
Those having Mn) of 1.6 or less are preferred because they are easy to handle. These polymers may be used alone or in combination of two or more.

In the room temperature curable composition of the present invention 1, the content of the titanium oxide (B) coated with apatite decreases as the content decreases, and the elongation after curing decreases as the content increases. Therefore, the amount is limited to 0.1 to 100 parts by weight based on 100 parts by weight of the organic polymer (A) of the first invention. The titanium oxide used for the apatite-coated titanium oxide (B) is preferably an anatase-type titanium oxide having a high photocatalytic effect.

In addition to the organic polymer (A) and the titanium oxide (B) coated with apatite, the following compounds can be added to the room temperature-curable composition of the present invention 1 if necessary.

(1) Compound having an amino group and an alkoxysilyl group in one molecule Specific examples of the above compound include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, and 3-aminopropyltrimethoxysilane. Ethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl Triethoxysilane,
N, N′-bis- [3- (trimethoxysilyl) propyl] ethylenediamine, N, N′-bis- [3- (triethoxysilyl) propyl] ethylenediamine,
N'-bis- [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N'-bis- [3- (trimethoxysilyl) propyl] hexamethylenediamine,
N, N'-bis- [3- (triethoxysilyl) propyl] hexamethylenediamine, N, N'-bis- [3-
(Methyldimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (trimethoxysilyl) propyl] ethylenediamine, N, N-bis- [3
-(Methyldimethoxysilyl) propyl] ethylenediamine, N, N-bis- [3- (triethoxysilyl) propyl] ethylenediamine, N, N-bis- [3- (trimethoxysilyl) propyl] hexamethylenediamine, N-bis- [3- (methyldimethoxysilyl)
Propyl] hexamethylenediamine, N, N-bis-
[3- (triethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (trimethoxysilyl) propyl] amine, N, N-bis- [3- (triethoxysilyl) propyl] amine, N, N-bis- [3
-(Methyldimethoxysilyl) propyl] amine and the like, and these can be used alone or in combination of two or more.

(2) Silanol condensation catalyst For example, dibutyltin dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin phthalate,
Tin compounds such as bis (dibutyltin laurate) oxide, dibutyltin bisacetylacetonate, dibutyltin bis (monoester malate), tin octylate, dibutyltin octoate, dioctyltin oxide, tetra-n
-Butoxytitanate, titanate compounds such as tetraisopropoxytitanate, amine salts such as dibutylamine-2-ethylhexoate, and other acidic catalysts and basic catalysts, and the like, alone or in combination of two or more. It can be used in combination.

(3) Dehydrating agent For example, vinyl trimethoxysilane, dimethyldimethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethylsilane, diphenyldimethoxysilane, etc. Silane compounds,
Examples include hydrolyzable ester compounds such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, and ethyl orthoacetate, and these can be used alone or in combination of two or more.

(4) Anti-sagging agent For example, an anti-sagging agent such as hydrogenated castor oil, fatty acid bisamide and fumed silica may be added.

(5) Various additives For example, calcium carbonate, magnesium carbonate, hydrous silicic acid, anhydrous silicic acid, calcium silicate, silica, titanium dioxide, clay, talc, carbon black, glass balloon and the like can be mentioned. They can be used alone or in combination of two or more. Further, an antioxidant, an antioxidant, an ultraviolet absorber, a pigment, a solvent, a fragrance and the like can be used as needed.

The room temperature curable composition of the present invention 2 is the same as that of the present invention 1
This is the same as the room temperature curable composition of the present invention 1 except that the coating thickness of the titanium oxide (B) coated with apatite is 0.1 to 5 nm among the room temperature curable compositions of the above. The apatite coating thickness of the titanium oxide (B) is 0.1 to 5
If it is nm, the stain resistance of the room temperature curable composition of the present invention is further improved.

The room temperature curable composition of the present invention 3 is the same as that of the present invention 1
Or, it is the same as the room temperature curable composition of the present invention 1 or 2, except that the particle diameter of the titanium oxide (B) coated with apatite is 20 to 40 nm in the room temperature curable composition of the second embodiment. The particle diameter of the titanium oxide (B) is 20 to 40 n
When m, the stain resistance of the room temperature curable composition of the present invention is further improved.

(Function) The titanium oxide (B) coated with apatite in the room-temperature curable composition of the present invention has an apatite layer on its surface. The photocatalytic performance can be exhibited without decomposing the organic substance itself such as the organic polymer (A). By exhibiting this photocatalytic performance, dirt substances such as dust and exhaust gas adhering to the surface of the room temperature curable composition of the present invention can be decomposed, and the dirt resistance can be improved over a long period of time.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited only to the following examples.

Examples 1 to 3 A predetermined amount (parts by weight) of a modified silicone polymer (Exastar ESS2420, number average molecular weight 17000, manufactured by Asahi Glass Co., Ltd.) shown in Table 1 and colloidal calcium carbonate (Shiraishi Kogyo Co., Ltd.) as a filler Made,
CCR), as a pigment, titanium oxide (manufactured by Ishihara Sangyo, Taibake R-820), as a plasticizer, polypropylene glycol (manufactured by Asahi Glass Co., Ltd., Exercise 3020), and as a light stabilizer, Sankyo LS770, Ciba Chemical Specialties Manufactured by Tinuvin 327,
The apatite-coated titanium oxide (anatase type) of the present invention is mixed in a sealed stirrer for 30 minutes, dehydrated under reduced pressure at 110 ° C. for 2 hours, cooled to 30 ° C., and then adjusted for physical properties. As an agent, a predetermined amount (parts by weight) of vinyltrimethoxysilane shown in Table 1
N- (2-aminoethyl) -3-aminopropylmethyltrimethoxysilane and dibutyltin dilaurate were added and mixed in a stirrer for 20 minutes to obtain a room temperature curable composition.

COMPARATIVE EXAMPLE 1 The same procedure as in Examples 1 to 3 was carried out except that a predetermined amount (parts by weight) of the same material as in Examples 1 to 3 shown in Table 1 was not added to the titanium oxide coated with apatite of the present invention. In the same manner as in Examples 3 to 3, a room temperature curable composition was obtained.

[Evaluation of Stain Resistance] A sheet having a size of 50 mm × 50 mm and a thickness of 2 mm was prepared using the room temperature curable composition, and after curing at 23 ° C. and a relative humidity of 55% for one week, the sheet was cured. At an exposure site in Chikko Shinmachi, Sakai City, Osaka City, for 3 months under an outdoor exposure test at a temperature of 30 ° on the south side. The lightness index L * before and after the test was measured using a colorimeter (Minolta,
CIE (International Commission on Illumination) 1 using model CR-300)
The measurement was carried out according to 976, and the stain resistance was evaluated according to the following criteria. Table 1 shows the evaluation results. ：: (L * value before test−L * value after test) is 15 or less. X: (L * value before test−L * value after test) is more than 15 and 25 or less.

[0025]

[Table 1]

[0026]

By using the room temperature curable composition of the present invention, the plasticizer bleeds out on the surface of the cured product, such as a sealing material containing a high molecular weight plasticizer, which has been a problem. This solves the problem that dirt such as dust and exhaust gas adheres, and the dirt is easily contaminated. This is because the apatite-coated titanium oxide used in the present invention decomposes the organic substance itself such as the organic polymer in the above composition, like the conventional titanium oxide, by the function of the apatite layer on the surface. This is because photocatalytic performance can be exhibited. By this photocatalytic performance, a performance of decomposing dirt substances such as dust and exhaust gas adhered to the surface of the cured product and improving the dirt resistance over a long period of time is exhibited.

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Claims (3)

[Claims] (A) 100 parts by weight of an organic polymer containing a silicon atom bonded to a hydroxyl group or a hydrolyzable group and having at least one functional group capable of crosslinking by forming a siloxane bond; A room temperature curable composition comprising 0.1 to 100 parts by weight of titanium oxide coated with apatite. 2. The room temperature curable composition according to claim 1, wherein the coating thickness of the titanium oxide coated with apatite is 0.1 to 5 nm. 3. The titanium oxide coated with apatite has a particle size of 20 to 40 nm.
Or the room temperature curable composition according to 2.