JP3149347B2 - Coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition which forms a coating film having excellent storage stability and excellent hot water resistance, crack resistance, weather resistance, stain resistance and the like.

[0002]

2. Description of the Related Art In recent years, coating compositions using an organopolysiloxane as a binder, which forms a coating film having excellent heat resistance, water resistance, chemical resistance, weather resistance, etc., have been widely used. Examples of such coating compositions include, for example, JP-A-4-198286 and JP-A-5-94.
39, JP-A-5-179202, JP-A-2-173
No. 174 and the like.

[0003] However, a coating composition containing an organopolysiloxane as a binder generally undergoes a condensation reaction during storage of the organopolysiloxane, tends to thicken and gel, and has insufficient storage stability. The resulting coating film has problems such as poor hot water resistance and crack resistance.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has excellent storage stability, hot water resistance, crack resistance (freezing damage resistance) and the like. An object is to provide a coating composition capable of forming a coating film.

[0005]

The present invention SUMMARY OF] is, (a) the general formula _{^{(1) R 1 n Si (}} OR 2) 4-n [ wherein R ¹ is an alkyl group having 1 to 8 carbon atoms, .gamma.-chloro Propyl group, vinyl
Group, 3,3,3-trifluoropropyl group, γ-glyci
Doxypropyl group, γ-methacryloxypropyl group,
γ-mercaptopropyl group, phenyl group, 3,4-epoxy
Xycyclohexylethyl group and γ-aminopropyl group
Organic group selected from the group consisting of, and R ² is an alkyl group having 1 to 5 carbon atoms, n represents an organosilane and / or a partial hydrolytic condensate 100 parts represented by 1 or 2 which is, ( b) the general formula ^{_{(2) R 1 3 SiOR 2}} [ wherein R ^1, R ² are as defined above] 0.3 to 20 parts by weight of an organosilane represented by, is distributed to (c) a hydrophilic organic solvent The present invention provides a coating composition using a reaction product obtained by reacting 0 to 50 parts by weight of colloidal silica (in terms of solid content) with a binder.

Hereinafter, the present invention will be described in detail.

First, each component used for producing the binder of the present invention will be described. (A) Component The component (a) is represented by the general formula (1) R ¹ _n Si (OR ² ) _4-n
[Wherein R ¹ is an organic group having 1 to 8 carbon atoms, and R ² is an organic group having 1 to 8 carbon atoms.
And n is 1 or 2], and / or a partially hydrolyzed condensate thereof.

R ¹ in the above general formula is an organic group having 1 to 8 carbon atoms, for example, an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a γ-chloropropyl group, Vinyl group, 3,3,3-trifluoropropyl group, γ-glycidoxypropyl group, γ-methacryloxypropyl group, γ-mercaptopropyl group, phenyl group, 3,4-epoxycyclohexylethyl group, γ
-Aminopropyl group and the like.

R ² in the organosilane is an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group,
Examples include an s-butyl group, a t-butyl group, an i-butyl group, and the like.

Specific examples of these organosilanes include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyl Trimethoxysilane, i-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyl Pills triethoxysilane, .gamma.-mercaptopropyltrimethoxysilane, .gamma.
Mercaptopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-aminopropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, dimethyldimethoxysilane, Dimethyl diethoxy silane, diethyl dimethoxy silane, diethyl diethoxy silane, diphenyl dimethoxy silane, diphenyl diethoxy silane, dimethoxy methyl phenyl silane, dimethyl dipropoxy silane and the like, preferably methyl trimethoxy silane, methyl triethoxy silane , Dimethyldimethoxysilane.

These organosilanes can be used alone or in combination of two or more.

The component (a) may be a partially hydrolyzed condensate of the organosilane described above. The polystyrene-equivalent weight average molecular weight of the condensate is 300 to 5,000.
0, preferably 500 to 3,000, and a condensate having such a molecular weight can provide a coating film having good adhesion without deteriorating storage stability.
The partially hydrolyzed condensate of the organosilane to an -OH group or -OR ² group bonded to a silicon atom 1 or more, and preferably those having 3 to 30. Specific examples of such a condensate include commercial products such as SH6018, SR2402, DC3037, and Dow Corning Toray.
DC3074: KR-211, KR manufactured by Shin-Etsu Chemical Co., Ltd.
-212, KR-213, KR-214, KR-21
6, KR-218; TSR-14 manufactured by Toshiba Silicone Co., Ltd.
5, TSR-160, TSR-165, YR-3187
And the like.

In the present invention, the component (a) has a weight ratio of the organosilane represented by the above-mentioned general formula (1) to its partially hydrolyzed condensate (5:95 to 75:25), preferably (15). : 85 to 70:30) is preferable since a coating film having good adhesion and appearance can be obtained.

The component (a) is represented by n in the aforementioned general formula (1).
The weight ratio of the organosilane having a value of 1 and / or its partially hydrolyzed condensate (a-1) to the organosilane having an n value of 2 and / or its partially hydrolyzed condensate (a-2) is (5)
0: 50-100: 0), preferably (55: 45-9)
The mixture of 5: 5) is preferred because it stably polymerizes when producing the binder and a coating film having good crack resistance is obtained. (B) Component (b) component, the general formula _{^{(2) R 1 3 SiOR 2}} [ wherein R
¹ and R ² are the same as those in the general formula (1) of the component (a)].

Specific examples of the organosilane include methoxytrimethylsilane, ethoxytrimethylsilane, ethoxydiphenylmethylsilane, methoxydimethylvinylsilane, 1-methylpropoxytrimethylsilane, i
-Butoxytrimethylsilane, n-butoxytrimethylsilane, t-butoxytrimethylsilane, i-propoxytrimethylsilane and the like. These organosilanes can be used alone or in combination of two or more. .

The component (b) is used for improving the storage stability of the coating composition and for improving the hot water resistance and crack resistance of the resulting coating film.

Therefore, the component (b) is replaced by the component (a) 100
0.3 to 20 parts by weight, preferably 1 to 1 part by weight,
It is necessary to use 0 parts by weight.

If the amount of the component (b) is less than the above range, the above-mentioned improvement effect cannot be obtained. Conversely, if the amount is too large, the curability of the obtained coating film deteriorates, and the stain resistance, weather resistance, solvent resistance, It is not preferable because the appearance is deteriorated. Component (c) Component (c) is used to convert silicic anhydride to alcohols such as methanol, ethanol and isopropanol, alcohol ethers such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether, and ketones such as acetone and methyl ethyl ketone. Colloidal silica dispersed in an organic solvent. Colloidal silica is
Usually, the average particle size is 5 to 30 mμ, preferably 10 to 20 mμ.
Is dispersed in a hydrophilic organic solvent having a solid content of 10 to 40% by weight.

Commercial products of such colloidal silica include isopropanol silica sol and methanol silica sol manufactured by Nissan Chemical Industry Co., Ltd., and Oscar manufactured by Catalyst Chemical Industry Co., Ltd.

It is not necessary to use the component (c) in particular. However, in order to improve the solvent resistance, adhesion and the like of the obtained coating film, the component (c) is converted to a solid content based on 100 parts by weight of the component (a). It is appropriate to use 50 parts by weight or less, preferably 5 to 40 parts by weight. In addition, when the component (c) is more than the above range, cracks easily occur in the obtained coating film,
Further, the water resistance is undesirably reduced.

The binder used in the present invention is obtained by subjecting the components (a), (b) and (c) described above to hydrolysis and partial condensation in the presence of water, To manufacture.

The amount of water is one of the functional groups (-OR group, -OH group) in the components (a), (b) and (c).
0.2 to 1.0, preferably 0.3 to 0.4,
The equivalent is appropriate. Acetic acid to promote the reaction,
Acids such as hydrochloric acid, nitric acid and formic acid may be added as needed.

The hydrolysis and the partial condensation reaction are usually carried out at 40 to 8
It is appropriate to carry out the reaction at 0 ° C., preferably 45 to 65 ° C. for 2 to 15 hours, but it is also possible to carry out the reaction at room temperature.

The coating composition of the present invention uses the above-described reaction product as a binder, and if necessary, adjusts the solid content of the composition to preferably about 5 to 50% by weight. It is composed of a mixture of an organic solvent, a filler, various additives such as a dye, a curing accelerator, a thickener, a pigment dispersant and the like for improving the storage stability of the product and the workability of coating.

As the organic solvent, in addition to the above-mentioned hydrophilic organic solvents, various coating organic solvents such as toluene, xylene, ethyl acetate and butyl acetate can be used.

As the filler, extenders and coloring pigments for various paints such as talc, barium carbonate, calcium carbonate, barium sulfate, bentonite, titanium oxide, carbon black, red iron, lithopone and the like can be used.

Representative examples of the curing accelerator include organotin compounds such as tin octylate, dibutyltin dilaurate, dibutyltin dimaleate and tributyltin laurate, and amine compounds such as ethylenediamine, diethylenetriamine, piperidine, phenylenediamine and triethylamine. It is listed as. These curing accelerators are desirably added to cure the coating composition faster at a relatively low temperature, and the amount thereof is suitably 0.01 to 15 parts by weight based on 100 parts by weight of the binder. .

The coating composition of the present invention is formed by applying a coating method such as a brush, a spray, a roll, or dipping on the surface of an object to be coated, and baking at room temperature or a temperature of 300 ° C. or less to form a cured coating film. Is possible.

The object to be coated can be applied to various objects to be coated such as inorganic ceramic substrate, various metal substrates such as stainless steel and aluminum, glass substrate, plastics substrate and paper substrate.

[0030]

The coating composition of the present invention can form a coating film which is excellent in storage stability, hot water resistance, frost damage resistance (crack resistance), weather resistance, stain resistance and the like. .

[0031]

The present invention will be described in more detail with reference to the following examples. In the examples, "parts" and "%" are shown on a weight basis unless otherwise specified. Example 1 In a reactor equipped with a reflux condenser and a stirrer, 40 parts of a partially hydrolyzed condensate of methyltrimethoxysilane (SR2402, manufactured by Dow Corning Toray Co., Ltd .; solid content: 100%) were placed in a reactor.
, 50 parts of methyltrimethoxysilane, 10 parts of dimethyldimethoxysilane, (b) 1 part of trimethylmethoxysilane and 20 parts of isopropanol, and after mixing, (d) 20 parts of ion-exchanged water are added with stirring, and then (C)
30 parts of colloidal silica (manufactured by Nissan Chemical Industries, Ltd., isopropanol silica sol; solid content: 30%) were added, and 60 parts were added.
After 3 hours of reaction at 60 ° C., 60 parts of isopropanol was added and the mixture was cooled to room temperature.
%). Example 2 In a reactor equipped with a reflux condenser and a stirrer, (a) 70 parts of SR2402 manufactured by Dow Corning Toray Co., Ltd., 20 parts of isopropyltrimethoxysilane, 10 parts of dimethyldimethoxysilane, and (b) After adding and mixing 1 part of trimethylmethoxysilane and 20 parts of isopropanol, 20 parts of (d) ion-exchanged water is added with stirring, and then (c) 30 parts of isopropanol silica sol manufactured by Nissan Chemical Industries, Ltd. After reacting for 3 hours at 60 ° C., 60 parts of isopropanol was added, and the mixture was cooled to room temperature.
(Solid content 35%) was obtained. Example 3 In a reactor equipped with a reflux condenser and a stirrer, (a) 50 parts of SR2402 manufactured by Dow Corning Toray, 50 parts of methyltrimethoxysilane, and (b) n-butoxytrimethylsilane 1 After adding and mixing 20 parts of isopropanol and stirring, (d) 20 parts of ion-exchanged water are added with stirring, then (c) 100 parts of isopropanol silica sol manufactured by Nissan Chemical Industries, Ltd. are added, and the mixture is added at 60 ° C. for 3 hours. After the reaction, 60 parts of isopropanol was added and the mixture was cooled to room temperature to obtain a coating composition C (solid content: 32%). Example 4 In a reactor equipped with a reflux condenser and a stirrer, (a) 40 parts of SR2402 manufactured by Dow Corning Toray Co., Ltd., 50 parts of methyltrimethoxysilane, 10 parts of dimethyldimethoxysilane, and (b) ) 3 parts of trimethylmethoxysilane and 20 parts of isopropanol were added and mixed, and then, with stirring, (d) 20 parts of ion-exchanged water were added, and then (c) 30 parts of isopropanol silica sol manufactured by Nissan Chemical Industry Co., Ltd. were added. After reacting at 60 ° C. for 3 hours, isopropanol 6
0 parts were added and the mixture was cooled to room temperature to obtain a coating composition D (solid content: 32%). Example 5 In a reactor equipped with a reflux condenser and a stirrer, (a) 30 parts of SR2402 manufactured by Dow Corning Toray Co., Ltd., 65 parts of methyltrimethoxysilane, 5 parts of dimethyldimethoxysilane, and (b) After adding and mixing 1 part of trimethylmethoxysilane and 20 parts of isopropanol, (d) 20 parts of ion-exchanged water are added with stirring, then 0.1 part of 0.1 N hydrochloric acid is added, and the mixture is reacted at 60 ° C. for 3 hours. Thereafter, 60 parts of isopropanol was added and the mixture was cooled to room temperature to obtain a coating composition E (solid content: 30%). Comparative Example 1 In a reactor equipped with a reflux condenser and a stirrer, (a) 40 parts of SR2402 manufactured by Dow Corning Toray Co., Ltd., 50 parts of methyltrimethoxysilane, 10 parts of dimethyldimethoxysilane and 20 parts of isopropanol were added. After adding and mixing, (d) 20 parts of ion-exchanged water was added with stirring, then (c) 100 parts of isopropanol silica sol manufactured by Nissan Chemical Industries, Ltd. was added, and the mixture was reacted at 60 ° C. for 3 hours, and then 60 parts of isopropanol. And cooled to room temperature to obtain a coating composition F (solid content 32%). Comparative Example 2 (a) In a reactor equipped with a reflux condenser and a stirrer, (a) 40 parts of SR2402 manufactured by Dow Corning Toray Co., Ltd., 50 parts of methyltrimethoxysilane, 10 parts of dimethyldimethoxysilane, and (b) After adding and mixing 50 parts of trimethylmethoxysilane and 20 parts of isopropanol, add (d) 20 parts of ion-exchanged water with stirring, and then add (c) 30 parts of isopropanol silica sol manufactured by Nissan Chemical Industries, Ltd. After reacting at room temperature for 3 hours, isopropanol 6
0 parts were added and the mixture was cooled to room temperature to obtain a coating composition G (solid content: 36%). Comparative Example 3 In a reactor equipped with a reflux condenser and a stirrer, (a) 40 parts of SR2402 manufactured by Dow Corning Toray Co., Ltd., 50 parts of methyltrimethoxysilane, 10 parts of dimethyldimethoxysilane, and (b) After adding and mixing 1 part of trimethylmethoxysilane and 20 parts of isopropanol, 20 parts of (d) ion-exchanged water is added with stirring, and then (c) 300 parts of isopropanol silica sol manufactured by Nissan Chemical Industries, Ltd. After reacting at 3 ° C. for 3 hours, 60 parts of isopropanol was added and cooled to room temperature to obtain a coating composition H (solid content: 32%). <Performance Evaluation Test> (i) Coating Composition Storage Stability Test The coating compositions A to H obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were allowed to stand in a 50 ° C. thermostat for 4 weeks, and the appearance change was observed. The viscosity change was examined. Coating composition A ~
No change was observed in E, G and H, but the coating composition F of Comparative Example 1 which did not contain the component (b) thickened. (Ii) Coating composition coating film performance test Preparation of test plate: Gypsum slag perlite plate (thickness: 12 mm) was used as a material, and a polyisocyanate prepolymer solution sealer “V-Selan # 100 Sealer” was used on the surface.
(Product name, manufactured by Dainippon Paint Co., Ltd.)
Spray coating was performed to 100 g / m ² (wet weight). This was dried at 100 ° C. for 5 minutes. Next, an acrylic silicone resin-based paint “V-Seran # 5” was used as a base paint.
00 enamel "(trade name, manufactured by Dainippon Paint Co., Ltd.) (a product diluted 40% with a solvent of butyl acetate: xylene = 1: 1) so that the coating amount is 80 to 90 g / m ² (wet weight). Painted. This was dried at 120 ° C. for 15 minutes.

Next, a top coat paint (the numerical values in the table indicate "parts") shown in Table 1 in which an organic solvent, a curing accelerator, etc. were added to each of the above-mentioned coating compositions, and the coating amount was 70 to 70%.
The spray coating was performed so as to be 80 g / m ² (wet weight). This was dried at 120 ° C. for 15 minutes, and then dried at room temperature for 3 days. The resulting coating film had a hardness, hot water resistance, stain resistance,
Each test of weather resistance and frost damage resistance was performed, and the results are shown in Table 1.

The test method and evaluation criteria are as follows.

Hardness: Pencil hardness measured according to JIS K5400 Hot water resistance: The test piece was immersed in tap water at 60 ° C. for 7 days, and the appearance of the coating film was visually judged.

○: No change Δ: Minor change such as gloss reduction, whitening, etc. ×: Large change such as gloss reduction, whitening, etc. Stain resistance: decontamination property of red and black magic inks after 24 hours ◎: Complete Removal, ○: extremely slight contamination, Δ: contamination, ×: marked contamination Weather resistance: Sunshine Weather-O-Meter 3000
Time…: no change in appearance of coating film, gloss retention of 95% or more…: slight change in appearance of coating, gloss retention of 80 to 94
% ×: Significant change in appearance of coating film, gloss retention less than 80% Frost damage resistance: Measured by ASTM-C666A method ◎: No cracking, ○: Extremely slight cracking, Δ: Cracking or coating Partial peeling, × ... significant cracks, peeling of coating film As apparent from Table 1, Test No. 1 using the coating composition of the present invention as a top coat paint. Nos. 1 to 5 had excellent coating performance.

On the other hand, the coating composition F containing no component (b) of Comparative Example 1 was poor in hot water resistance and frost damage resistance (crack resistance). Conversely, the coating composition G of Comparative Example 2 containing an excessive amount of the component (b) was low in hardness, and very poor in stain resistance and weather resistance. The coating composition H containing the component (c) in Comparative Example 3 in excess was
The frost resistance was poor.

[0037]

[Table 1]

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09D 1/00-201/10

Claims (4)

(57) [Claims] (A) General formula (1) R ¹ _n Si (OR ² )
_{4-n wherein} R ¹ is an alkyl group having 1 to 8 carbon atoms , γ-chloro
Propyl group, vinyl group, 3,3,3-trifluoropropyl
Γ-glycidoxypropyl group, γ-methacryloyl group
Xypropyl group, γ-mercaptopropyl group, phenyl
Group, 3,4-epoxycyclohexylethyl group and γ-
Organic group selected from the group consisting of an aminopropyl group, R ²
An alkyl group having 1 to 5 carbon atoms, n represents 1 or 2.] In the organosilane and / or a partial hydrolytic condensate 100 parts by weight shown (b) the general formula _{^{(2) R 1 3 SiOR 2}} [ Wherein R ¹ and R ² are the same as those described above], and 0.3 to 20 parts by weight of (c) colloidal silica (in terms of solid content) dispersed in a hydrophilic organic solvent. A coating composition containing, as a binder, a product obtained by reacting 2. The coating composition according to claim 1, wherein the component (a) has a weight ratio of the organosilane of the general formula (1) to its partially hydrolyzed condensate of (5:95 to 75:25). . 3. The component (a) has the general formula R ¹ Si (O
R ²⁾ ₃ [wherein R ^1, R ² are as defined above organosilane and / or its partially hydrolyzed condensate represented by (a-1) and the general formula _{^{R 1 2 Si (OR 2)}} 2 [ Formula R ¹ and R ² are the same as above.
The weight ratio with the organosilane and / or its partially hydrolyzed condensate (a-2) represented by
0: 0). 4. The component (a) has a general formula R ¹ Si (O
R ²⁾ ₃ [wherein R ^1, R ² are as defined above organosilane and / or its partially hydrolyzed condensate represented by (a-1) and the general formula _{^{R 1 2 Si (OR 2)}} 2 [ Formula R ¹ and R ² are the same as above.
And the weight ratio thereof to the organosilane and / or its partially hydrolyzed condensate (a-2) represented by the formula (55:45 to 95:
3. The coating composition according to claim 1, comprising 5).