JPH01306476A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the title composition outstanding in adhesivity to substrates and resistance to scratch, hot water, light, acid, etc., of the coating film therefrom, for application on e.g., plastic products by incorporating silica fine granules in a partial condensate from each specific trialkoxy silane and tetra- alkoxysilane. CONSTITUTION:The objective composition can be obtained by incorporating (A) 100 pts.wt. of a partial condensate of organosilicon compound (RSiO3/2+ SiO2) produced from A1: 100 pts.wt. of a trialkoxysilane of the formula RSi(OR')3 (R is C1-6 hydrocarbon; R' is C1-6 alkyl) and A2: 20-130 pts.wt. of a tetra- alkoxysilane of the formula Si(OR<2>)4 CR<2> is C1-6 alkyl) with (B) 0.05-200 pts.wt. of silica fine granules and, if needed, (C) 0.02-15 pts.wt. of titania fine granules.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to the surface of plastic products, ceramic products, glass products, etc. for the purpose of imparting wear resistance, weather resistance, hot water resistance, etc. The present invention relates to a coating composition.

[Prior Art] Among various coating compositions, organic alkoxysilane-based coating compositions are known as those used for the above purpose. For example, JP-A-48-26822
No. Publication and Japanese Patent Application Laid-open No. 1983. JP-A-33128 describes a coating composition whose main component is a partial condensate of an alkyltrialkoxysilane and a tetraalkoxysilane. Also, JP-A-51-2736, JP-A No. 53-130
No. 732, No. 55-94971, No. 59-68377
No. 62-79274 and the like describe coating compositions in which colloidal silica is blended with a partial condensate of organic alkoxysilane. Furthermore, JP-A-5
No. 5-106261.

Publications such as No. 62-57470 describe compositions in which colloidal silica and colloidal titania are blended with partial condensates of silanol or alkoxysilane.However, coatings obtained from these conventional coating compositions are described. However, they are not necessarily satisfactory in terms of scratch resistance, hot water resistance, light resistance, etc., and also have problems such as short pot life of one composition.

By the way, natural marble, which is used as flooring material, wall material, interior decoration material, etc., has poor weather resistance when used as a raw material, and is easily altered by the adhesion of pollutants, causing deterioration in gloss, color tone, etc. . For this reason, it has conventionally been customary to apply wax to the surface of natural marble, or to form a protective film of acrylic-silicon resin, fluororesin, or the like. However, these protective coatings not only have insufficient scratch resistance and weather resistance, but also have the disadvantage that they tend to peel off from natural marble.

Incidentally, when the conventional organic alkoxysilane coating composition described above is applied to natural marble, the adhesion of the film is poor, so it is not suitable for protecting natural marble.

Here, the present inventors have found that the drawbacks of conventional organic alkoxysilane coating compositions can be overcome by incorporating silica fine particles into a partial condensate of a specific trialkoxysilane and tetraalkoxylan. I found it. Furthermore, by adding a small amount of titania fine particles in addition to the silica fine particles, the acid resistance of the coating obtained from the composition can be further improved, and this coating is particularly suitable as a surface protective coating for natural marble. I discovered that.

[Structure of the Invention] The coating composition of the present invention contains (a) the general formula: RS i (OR1) 3 (R: a hydrocarbon group having 1 to 6 carbon atoms, R1: a hydrocarbon group having 1 to 6 carbon atoms) as an essential component. 100 parts by weight of trialkoxysilane represented by the alkyl group] and general formula: 5i
(OR2) a partial condensate of an organosilicon compound consisting of 20 to 130 parts by weight of tetraalkoxysilane represented by 4[R2: alkyl group having 1 to 6 carbon atoms], and (b) the trialkoxysilane to R31O, / 2 and tetraalkoxysilane as SiO2, the partial condensate of (a) (RS
x 03/2 + S x 02) It is characterized by containing 0.05 to 200 parts by weight of silica fine particles per 100 parts by weight.

In the above trialkoxysilane R91 (OR1), R is a carbonized carbon having 1 to 6 carbon atoms, exemplified by methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, vinyl group, phenyl group, etc. Any hydrogen group may be used, and R1 may be a methyl group, an ethyl group, a propyl group, a butyl group,
The trialkoxysilane of the present invention may be any alkyl group having 1 to 6 carbon atoms, exemplified by pentyl group, hexyl group, etc. Ethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane,
Vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane and the like are included. In the present invention, two or more of the above trialkoxysilanes may be used in combination.

R2 in tetraalkoxysilane S i (OR2) is a methyl group, an ethyl group, a propyl group, a butyl group,
Any linear or branched alkyl group having 1 to 6 carbon atoms, exemplified by pentyl group, hexyl group, etc., may be used. Therefore,
Examples of tetraalkoxysilanes having a linear alkyl group include tetraethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrapentyloxysilane, and tetrahexyloxysilane. Two or more of these tetraalkoxysilanes can also be used in combination.

The partial condensate of the organosilicon compound used in the coating composition of the present invention can be prepared by mixing the trialkoxysilane and tetraalkoxysilane described below in the proportions described below, and by hydrolyzing this mixture, or by the method of hydrolyzing the mixture. It can be prepared by separately hydrolyzing alkoxysilane and tetraalkoxysilane and then mixing the respective hydrolysis products. but.

By hydrolyzing tetraalkoxysilane in advance, a partial condensate having an average molecular weight of preferably about 300 to 700 is prepared, and this partial condensate or a commercially available product equivalent thereto is mixed with trialkoxysilane in a predetermined ratio. However, it is preferable to hydrolyze this.

No matter which method is adopted, the mixing ratio of trialkoxysilane and tetraalfoxysilane is 10% of the former.
20 to 130 parts by weight of the latter per 0 parts by weight, preferably 35 parts by weight
~70 parts by weight is allowed. If the latter is less than 20 parts by weight, the abrasion resistance and hot water resistance of the coating will decrease, and if it exceeds 130 parts by weight, the coating will tend to crack and the stability of the coating composition itself will deteriorate. Hydrolysis is carried out in a suitable organic solvent in the presence of water and a hydrolysis catalyst at a temperature range of about 10-90°C, preferably about 20-80°C. In this case, alcohols, ethers, esters, and glycols can be used as organic solvents.
Various inorganic or organic acids can be used as the hydrolysis catalyst.

The second essential component of the coating composition of the present invention is silica particles. For these silica particles, silica powder obtained by thermally decomposing silicon tetrachloride etc. can be used, and silica sol in which silica particles are dispersed in a dispersion medium can be used.
The use of silica sol is preferred in the present invention. The silica sol may be hydrosil or luganosol, and these can be blended into the composition as they are. The average particle size of the silica fine particles is preferably about 5 to 150 mμ, and particularly when it is desired to obtain a transparent coating, it is recommended to use silica fine particles having an average particle size of about 30 mμ or less.

The blending ratio of the silica fine particles is calculated by assuming that the partial condensate of the organosilicon compound of the present invention, that is, the trialkoxysilane used in producing component (a) above, is R81031z, and the tetraalkoxysilane is also calculated as SiO2. and the amount of component (a) (RS i 0.12+
S i O2), it is in the range of 0705 to 200 parts by weight, preferably 2 to 50 parts by weight, per 100 parts by weight.

If it is less than 0.05 parts by weight, a film with good adhesion to the substrate cannot be obtained, and if it exceeds 200 parts by weight, the stability of the composition decreases and it tends to gel or aggregate.

In particular, when the composition of the present invention is used for coating natural marble, if the content of silica fine particles in the coating composition increases, the coating may become white. It is desirable that the blending amount be 20 parts by weight or less based on the above calculation criteria.

In addition to the above-mentioned two essential components, the coating composition of the present invention includes:
By blending titania fine particles, the film obtained from the composition can be more effectively protected from contamination by acidic substances. The average particle size of titania fine particles is 5~
It is preferable that the particle size is 150 mμ, and particularly when a transparent coating is desired, the average particle size is preferably about 3011+μ or less. As the titania fine particles of the present invention, titania fine powder obtained by thermally decomposing titanium tetrachloride etc. can be used, but titania sol obtained by peptizing a hydrolyzate of titanium salt with acid or other known methods can be used. It is preferable to use

In particular, patent application No. 62-25295 filed earlier by the present applicant.
The titania sol obtained by the method described in the specification of application No. 3 has excellent transparency, is stable in the range of p) 12 to 11, and has good miscibility with organic solvents, so the titania fine particles of the present invention Suitable as a supply source. By the way, conventional titania sols are generally unstable in alkaline regions.

If this is used as a titania source in a coating composition, the composition must be kept acidic, but natural marble is attacked by acids, so such compositions cannot be used for natural marble coatings. .

The blending ratio of titania fine particles is 0.02 parts by weight per 100 parts of component (a) when the amount of component (a) is calculated as (R3iOψ+S i O2), as in the case of silica fine particles.
-15 parts by weight, preferably 0.05-10 parts by weight. If it is less than 0.02 parts by weight, the effect of adding titania will not be exhibited, and if it exceeds 15 parts by weight, the composition will gel or aggregate, resulting in a decrease in stability and a decrease in the transparency of the coating film. When using a composition for coating natural marble, as with silica particles, if the content of titania particles increases, the coating film will become white, so it is necessary to use a composition for coating natural marble. It is preferable that the amount of titania fine particles blended is 1.5 parts by weight or less based on the above calculation criteria.

The dispersion medium of the coating composition of the present invention is generally an organic solvent used when hydrolyzing the alkoxysilane compound of the present invention into a partially fastened article. Therefore, a small amount of water is allowed to coexist in this dispersion medium. The amount of component (a) in the coating composition can be arbitrarily selected in consideration of the thickness of the coating to be formed and the method of coating the composition, but typically, the amount of component (a) in the coating composition of the present invention is The solid content concentration of the composition for
It is about wt%. The coating composition of the present invention also includes:
Depending on the purpose of use, suitable amounts of additives commonly used in paints, such as anti-sagging agents, wetting agents, hardening agents, and leveling agents, can be blended. Coating to the base material can be done by any means such as spraying, roll coater, etc. After coating, the base material can be coated by drying naturally or by heating at a temperature of about 400°C or less. A desired coating can be formed on the surface of the material. If the thickness of the coating is about 1 to 5 microns, it is possible for the coating to exhibit the desired performance.

[Effects of the Invention] The coating composition of the present invention is not only stable for a long period of time compared to conventional similar products, but also has excellent adhesion to the substrate, scratch resistance of the coating, hot water resistance, light resistance, It has excellent acid resistance and other properties, and is particularly effective as a protective film for natural marble in terms of adhesion to marble and durability against contamination by acidic substances.

[Examples] Example 1 100 g of monomethyltrimethoxysilane, 37 g of partially clamped tetramethoxysilane (average molecular weight 470, manufactured by Mitsubishi Kasei [Methyl Silicate 51J)], and 130 g of isopropyl alcohol were mixed and thoroughly stirred. 151 g of 0.4 wt% acetic acid aqueous solution was added to this, and the mixture was heated to 50°C.
and heated for 60 minutes. The partially fastened product obtained in this way was heated to 25°C.
After cooling to
wt% of silica sol (roscAt manufactured by Catalysts & Chemical Industry Co., Ltd.,
'') was added to prepare a coating composition (A).

Examples 2 to 4 In preparing the composition (A), the coating composition (B ), ((
:), (D) was prepared.

Example S 0.6 g of titania sol with a TiO□ concentration of 10 wt% in which Ti02 particles with an average particle size of 30 mμ are dispersed in isopropyl alcohol is added to the coating composition (A) of Example 1 to form a coating composition (E). was prepared.

Incidentally, the above titania sol was prepared by the following method.

0.4tyt% titanium sulfate aqueous solution as TiO□,
A white slurry obtained by gradually adding 15% ammonia water until the pH reached 8.5 was filtered and washed to obtain a titania hydrate gel cake with a solid content concentration of 9 wt %. This cake was dispersed in pure water so that the Tie2 concentration was 2.0νt%, and then H2O,/TiO□=4(wt/
Aqueous hydrogen peroxide was mixed so that the resultant mixture was prepared as follows: and heated at 80° C. for 5 hours to obtain an aqueous titanic acid solution.

Next, in this titanic acid aqueous solution, an average particle size of 7 mμ, Sin
, 'a K 15wt% (7) It was added so that Tie2/Sin = 9 (wt/wt). Furthermore, add pure water to make the solid content concentration 1.0.
After adjusting to wt%, the mixture was heated at 95° C. for 624 hours to obtain a water-dispersed sol of titania particles having an average particle size of 24 mμ. Add ethyl silica 1 to 5102/T to this sol.
Mix so that lO2 = 0.3 (enemyt/νt),
After heating to about 70° C., isopropyl alcohol was added and water was removed by distillation to prepare an isopropyl alcohol-dispersed sol.

Examples 6 to 8 In the preparation example of the composition (E) described above, the preparations are shown in Table 1 in the same manner as above, except that the amount of titania sol, the average particle size of titania, and the amount of silica sol added were changed. Coating compositions (F), (G), and (H) were prepared.

However, in the titania sol preparation example shown in Example 5, the titania sol with an average particle size of 5 mμ used in composition (F)
The solid content concentration of the mixture of titanic acid aqueous solution and silica sol is 1
(Change to ht″1 and set the heating temperature of the mixture to 130°C.
This was prepared by changing the heating time to 11 hours.

Example 9 A coating composition (I) shown in Table 1 was prepared in the same manner as in Example 5 except that a water-dispersed titania sol was used instead of the isopropyl alcohol-dispersed titania sol used in Example 5.
was prepared.

Examples 10 to 11 Coating compositions (J) and (K) shown in Table 1 were prepared in the same manner as in Example 5 by changing the mixing ratio of monomethyltrimethoxysilane and tetramethoxysilane.

Example 12 A partial condensate of tetramethoxysilane with an average molecular weight of 682
A coating composition (L) was prepared in the same manner as in Example 5, except that "Methyl Silicate 53" (manufactured by Mitsubishi Kasei) was used.

Example 13 A coating composition (M
) was prepared.

Example 14 A coating composition (N) was prepared in the same manner as in Example 5 except that the organic solvent was replaced with ethanol.

Example 15 A coating composition (0) was prepared in the same manner as in Example 5 except that the amount of silica sol used was changed.

Examples 16-17 Silica sol with an average particle size of 45 mg (SiO2 concentration 30ti
t%) in the same manner as in Example 5.
P) and (Q) were obtained.

Comparative Examples 1 and 2 Coating compositions (R) and (S) were prepared in the same manner as in Example 5, except that the mixing ratio of monomethyltrimethoxysilane and tetramethodixylan was changed.

The coating composition (A
) to (S) were applied to the surface of natural marble or glass using Percoater N013, and then dried at 120°C.
A film with a thickness of 2 μm was formed.

Note that the surface of natural marble was polished with abrasive paper and then coated. The following tests were conducted on each of these film-formed test pieces.

(1) Adhesion: After applying cellophane tape, peel it off and visually observe the peeling status of the film.

(2) Hot water resistance: immersed in boiling water for 1 hour and then removed.

After pasting the Sellotape, do this Peel it off and visually observe the peeling status of the film.

(3) Scratch resistance: Rubbed 100 times with steel wool under a load of 5ooE and visually observed for scratches.

(4) Cooling cycle knee between 30℃ and 80℃
After 0 cycles, apply cellophane tape, peel it off, and visually inspect the appearance of the film.

(5) Stain resistance: 10z citric acid aqueous solution, green tea, black tea (
0.3 g of green tea or black tea soaked in 30 cc of hot water for 5 minutes) and Tabasco were dropped onto the film and left at room temperature for 24 hours.

Wash with water and visually inspect the appearance.

The test results are shown in Table-2.

(Margin below)

Claims (1)

[Claims] 1. (a) Trialkoxy of general formula: RSi(OR^1)_3 [R: hydrocarbon group having 1 to 6 carbon atoms, R^1: alkyl group having 1 to 6 carbon atoms] A partial condensate of an organosilicon compound consisting of 100 parts by weight of silane and 20 to 130 parts by weight of tetraalkoxysilane of the general formula Si(OR^2)_4 [R^2: alkyl group having 1 to 6 carbon atoms], ( b) The partial condensate (R
A coating composition containing 0.05 to 200 parts by weight of silica fine particles per 100 parts by weight of SiO_3_/_2+SiO_2). 2. In addition to the partial condensate of (a) and the silica fine particles of (b), further (c) titania fine particles are added to the partial condensate of (a) (RSiO_3_/_2+SiO_2) 100
A coating composition characterized by containing 0.02 to 15 parts by weight based on the weight part. 3, (a) 100 parts by weight of trialkoxysilane of the general formula: RSi(OR^1)_3 [R: hydrocarbon group having 1 to 6 carbon atoms, R^1: alkyl group having 1 to 6 carbon atoms]; A partial condensate of an organosilicon compound consisting of 20 to 130 parts by weight of tetraalkoxysilane of the general formula Si(OR^2)_4 [R^2: alkyl group having 1 to 6 carbon atoms], (b) trialkoxysilane; The partial condensate (R
0.05 to 200 parts by weight of silica fine particles per 100 parts by weight of SiO_3_/_2+SiO_2), and (c)
Partial condensate of (a) (RSiO_3_/_2+Si
O_2) Transparently coated marble whose surface is coated with a transparent film containing 0.02 to 1.5 parts by weight of titania fine particles per 100 parts by weight.