JPH0331380A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent heat resistance and wear resistance, etc., and giving coated layer having high hardness and high luster to the surface of metal or ceramics, etc., containing specific surface- modifying colloidal silica and organopolysiloxane. CONSTITUTION:(A) Colloidal silica containing silica particles having the surface modified with alkoxysilane compound (oligomer) having >=2 1-8C alkoxy group in a molecule is mixed with (B) organopolysiloxane as a condensate of organoalkoxysilane expressed by the formula (R is 1-8C organic group; R' is 1-5C alkoxy or 1-4C acyl) and having 500-10000 weight-average molecular weight calculated as polystyrene and contained in the aimed composition. Besides, 30-90wt.% the component A and 70-10wt.% the component B are preferably contained in the aimed composition in calculating as total solid content.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides heat resistance, abrasion resistance, and chemical resistance to the surfaces of metals, ceramics, glass, cement, etc.

The present invention relates to a method for producing a silicone-based coating composition that has excellent weather resistance, can form a thick coating film with high hardness, high gloss, and has excellent long-term storage stability.

(Prior art) The surfaces of various molded objects such as metals and ceramics are coated with silicone-based polymer compositions to provide smoothness, scratch resistance, chemical resistance, and corrosion resistance.

Efforts are being made to improve weather resistance, water resistance, etc.

For example, JP-A-53-88099 describes methylpolysilsesquioxane (what is silsesquioxane) obtained by hydrolyzing and polymerizing methyltrichlorosilane in a ketone-ether solvent in the presence of an amine? , referring to a siloxane in which the ratio of the number of oxygen atoms to silicon atoms is 1.5). This methylpolysilsesquioxane has a molecular weight of about 9000 to 100,000 and is soluble in organic solvents. When a coating film containing this methylpolysilsesquioxane is used to form a coating film, the film has heat resistance of 400°C or higher. However, it is not practical because it requires a long time of 2 hours or more at 200°C for curing. Furthermore, since volume shrinkage occurs due to the dehydration reaction during curing, there is a drawback that cracks occur when the film is made thicker.

In Japanese Patent Publication No. 53-5042, methyltrime I xysilane is added to aqueous colloidal silica, and p) is added to an organic acid.
A coating composition containing a reaction condensate obtained by adjusting I and a pigment (extender pigment) is disclosed.

According to this reaction, hydrolysis and condensation of methyltrimethoxysilane proceed, and at the same time, active silanol on the surface of the silica particles of colloidal silica also participates in the condensation reaction. Therefore, if the hydrolysis/condensation reaction is allowed to proceed excessively, the active silanol on the surface of the silica particles becomes involved in the reaction, which tends to cause aggregation/gelation of the silica particles. Therefore, it is necessary to set the reaction conditions to extremely mild conditions. Moreover, the resulting paint has poor stability because it contains much more water than is required for hydrolysis.

Therefore, it must be used within 24 hours after preparation. Furthermore, since the degree of condensation of methyltrimethoxysilane condensate, which is a film-forming component when forming a coating film, is low,
If the film thickness is thicker than that of Japan, there is a drawback that cranks will occur. The surface smoothness of the coating film is poor, and the gloss is also poor.

JP-A-62-105987 discloses a coating composition comprising a reaction mixture obtained by adding an aqueous acid solution to a mixture of a tetraalkyl silicate and an organosilica sol. This paint is used to coat the surface of a ceramic substrate to provide smoothness. This composition has the advantage that the molecular weight of the resulting polymer can be controlled by adjusting the amount and rate of water added during preparation. Furthermore, since tetrafunctional tetraalkyl silicate is used, the coating film obtained using the above composition has extremely excellent heat resistance. However, the silica particles of the organosilica sol react with the silanol groups generated by the reaction between the tetraalkyl silicate and water, causing aggregation and gelation of the silica particles.

This drawback is the same as in the case of Japanese Patent Publication No. 53-5042 which uses the above-mentioned methyltrimethoxysilane and aqueous colloidal silica. Furthermore, when preparing this composition, the amount of water added is adjusted to control the hydrolysis of the tetraalkyl silicate.

The alkoxy group is left in place to stabilize the resulting reaction mixture. As described above, since alkoxy groups remain in the polymer, in order to form a coating film using this paint, it is necessary to eliminate the alkoxy groups during curing of the paint film. Therefore, a post-process of firing at a high temperature of 500° C. or higher is required during curing.

5 inventors aimed at improving the above composition.

We have already proposed a coating composition obtained by reacting a condensate of a predetermined molecular weight obtained by hydrolyzing and condensing an alkoxysilane with an organosilica sol (Japanese Patent Application No. 1983).
2-331028).

Since this coating composition is prepared using the condensate having the above-mentioned predetermined molecular weight, the condensate reacts with the silica particles of the organosilica sol, resulting in a uniform and stable composition. However, the above-mentioned organosilica sol has poor reactivity because the surface of the silica particles is alkoxylated with a dispersion medium such as alcohol. When the reaction temperature is raised to increase reactivity, aggregation and gelation of silica particles occur.

Thus, in the above method, it is difficult to select reaction conditions for preparing one composition.

(Problem to be solved by the invention) The present invention solves the above-mentioned conventional problems.

The object is to provide a method for producing a silicone-based coating composition for coating the surfaces of metals, ceramic moldings, etc., which has the following properties: ■A coating composition that has excellent storage stability and can be stored for a long time without gelling; ■A coating composition that does not require long curing treatment at high temperatures when preparing a coating film, and can be used for relatively thick coatings. A coating composition that does not cause cracks when forming a coating film; and (2) a coating composition that can form a coating film that has excellent gloss, high hardness, and excellent adhesion to a substrate.

(Means and Effects for Solving the Problems) The coating composition of the present invention is a coating composition containing two surface-modified colloidal silicas and an organopolysiloxane. The silica is colloidal silica containing silica particles surface-modified with an alkoxysilane compound and/or a low condensate thereof having two or more alkoxy groups (having 1 to 8 carbon atoms) in one molecule. ; and the organopolysiloxane.

General formula RSi(OR')s (where R is 1 carbon number
~8 organic group, Ro is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms), and has a polystyrene equivalent weight average molecular weight of 500 to 500. 10,000, thereby achieving the above objective.

The alkoxysilane compound for preparing the surface-modified colloidal silica contained in the composition of the present invention has the following formula (
1), (II) and (I[[), and the low condensate of the alkoxysilane compound is
Compounds (+) to (III) above and the following formula (IV)
It is a low condensate obtained by hydrolyzing and condensing at least one selected from the group consisting of the following compounds.

-R7 1 (1) (II) 1 R'-0-3i-R1 0-R' (III) I R'-0-3i-Rt l+3 (rV) Here, R', R", R" are Each independently,
Organic group 1 having 1 to 8 carbon atoms, such as methyl group and ethyl group.

Alkyl groups such as propyl group and butyl group; phenyl group,
Aryl groups such as tolyl group and xylyl group; γ-chloropropyl group, vinyl group, γ-glycidoxypropyl L
These include y-methacryloyloxypropyl group, γ-mercaptopropyl group, T-aminopropyl L 3,4-epoxycyclohexyl group, and the like. R4, R5, R6 and R7 are each independently an alkyl group, a haloalkyl group,
cycloalkyl group.

It is an aryl group, an aralkyl group, or an acyl group.

Among the alkoxysilane compounds mentioned above, examples of the compound represented by (1) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and tetraphenoxysilane. Formula (I
Compounds represented by I) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriptoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, and propyltriethoxysilane.

Phenyltrimethoxysilane, phenyltriethoxysilane, T-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane,
T-methacryloxypropyltrimethoxysilane, T
Examples include -mercaptopropyltrimethoxysilane, T-aminopropyltrimethoxysilane, and 3,4-epoxycyclohexylethyltriethoxysilane. Expression (■
Examples of the compounds represented by ) include dimethyldimethoxysilane, dimethyljethoxysilane, dimethyldipropoxysilane, diphenyldimethoxysilane, and diphenyljethoxysilane.

Compounds represented by (IV) include trimethyltoxysilane, trimethylethoxysilane, trimethylpropoxysilane, trimethylbutoxysilane, triphenylmethoxysilane, triphenylethoxysilane, γ-
Examples include glycidoxypylmethyldimethoxysilane.

The above-mentioned low condensate of the alkoxysilane compound is prepared by a known production method, that is, by adding water to the above-mentioned alkoxysilane compound and further adding an acid catalyst described below if necessary to perform a condensation reaction. Ru. The molecular weight of the condensate obtained is preferably about 200 to 100.

The colloidal silica used in the present invention is a dispersion of ultrafine particles of silicic anhydride dispersed in a solvent.

The particle size of the silica particles is 5 to 200 mμ. When the particle size is less than 5111μ, cracks are likely to occur when the resulting paint is used to form a coating film and this is cured. On the other hand, if it exceeds 20 hμ, film forming properties are poor.

The resulting coating film has poor hardness and smoothness. Preferably it is 10 mμ to 2 μm. Examples of solvents are:

Alcohols such as methanol, ethanol, isopropanol and butanol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate; ethers such as diisopropyl ether and glycol ether; Examples include mixtures of. It is also possible to use aqueous colloidal silica dispersed in water, but in order to prevent a large amount of water from mixing in one reaction system, it is necessary to mix colloidal silica dispersed in an organic solvent, or add the required amount of water with an organic solvent. It is preferable to use distillation and substitution. Examples of such colloidal silica are commercially available, such as methanol silica sol, isopropatol silica sol, manufactured by Nissan Chemical Industries, Ltd., and Oscar, manufactured by Snowtex Catalysts and Chemicals. In both cases, the solid content concentration is 10 to 40% by weight.

The amount of the alkoxysilane compound and/or its low condensate compounded in the colloidal silica is such that a monomolecular film of the alkoxysilane compound and/or its low condensate compound is formed on the surface of the silica particles of the colloidal silica. It is preferable.

Therefore, the amount of colloidal silica is determined by the particle size of the silica particles. Specifically, the alkoxysilane compound and/or its low condensate is about 10 to 8 in terms of solid content.
0% by weight, preferably in the range 10-50% by weight, colloidal silica in the range 90-20% by weight, preferably 90-50% by weight.
It is contained in a proportion of % by weight. If the amount of the alkoxysilane compound and/or its low condensate is less than about 10% by weight, the surface of the colloidal silica will not be sufficiently modified, resulting in poor smoothness of the film formed from the final coating composition.

The gloss is also poor. The hardness of the film is also insufficient. If it exceeds about 80% by weight, the reaction solution becomes cloudy due to agglomeration of colloidal silica, resulting in whitening of the film formed from the final coating composition.

In the reaction between colloidal silica and an alkoxysilane compound and/or its low condensate, an acid catalyst is used as necessary. The acid catalyst has the function of promoting the polymerization reaction of alkoxysilane, its low condensate, and colloidal silica (organosilicon compound), and the polymerization reaction is controlled by appropriately setting the type and amount of this acid. Examples of acids include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and formic acid.
Any organic acid can be used, such as acetic acid. When an inorganic acid is used, it is used at a ratio of about 5 x 10-5 to 1 x lO-' parts by weight, preferably lXl0''' to 5 x lO-' parts by weight per 100 x lO-' of the organosilicon compound. If the amount exceeds 1X10-'' parts by weight, the condensation rate increases and it becomes difficult to control one reaction.

The resulting paint is more likely to form a gel during storage. When using an organic acid, it is 0.07 to 4 parts by weight, preferably 0.2 to 4 parts by weight, based on 100 parts by weight of the organosilicon compound.
It is used in a proportion of 2 parts by weight. If the organosilicon compound used contains an acid as an impurity or contains a compound that can be decomposed to produce an acid, the type and amount of the acid to be used must be determined taking these into consideration. be.

The method for surface-modifying the colloidal silica with the alkoxysilane compound and/or its low condensate is as follows. The alkoxysilane compound and/or its low condensate, and colloidal silica are mixed, and a water-soluble organic solvent is added thereto as necessary. As the water-soluble organic solvent, alcohol-based solvents, cellosolve-based solvents, cellosolve acetate-based solvents, glyme-based solvents, etc. are used. To this, water is added as appropriate, and if necessary, the above acid catalyst is added, and the mixture is heated for about 30 minutes to about 20 hours at a temperature of about 20 DEG C. to 5 reflux temperature to carry out a hydrolytic condensation reaction. The amount of water to be added is approximately 0.5 to 3 mol, preferably 0.8 to 3 mol, per mol of the alkoxy group of the alkoxysilane compound and/or its low condensate in one reaction system.
The amount should be 1.5 mol. If the blending ratio is less than 0.5 mole, there will be a large amount of unreacted alkoxy groups. If the blending ratio exceeds about 3 moles, polycondensation between the alkoxysilane compounds will proceed, and the resulting condensate will aggregate, resulting in turbidity of the solution, poor solution stability, and whitening during the film formation process. This deteriorates the appearance of the coating and reduces its performance.

(Left below) Although the reaction between the alkoxysilane compound and/or its low condensate and colloidal silica cannot be specified, the alkoxy group of the alkoxysilane compound and its condensate is hydrolyzed, and the resulting silanol group is colloidal. The silica reacts with the silanol groups or alkoxy groups on the surface of the silica particles to form new siloxane bonds. It is thought that a condensation reaction occurs. Through such a reaction, a coating film, preferably a monomolecular film, of the alkoxysilane condensate is formed on the surface of the silica particles of colloidal silica. If the reaction at this time is insufficient, when the final coating material is applied and cured by baking, the colloidal silica will be cured independently, resulting in whitening of the coating film and occurrence of cracks. On the other hand, if the reaction progresses excessively, the condensation of the alkoxysilane compounds proceeds simultaneously, resulting in aggregation and gelation of the silica. Even if gelation does not occur during the reaction, it often occurs during storage.

The organopolysiloxane contained in the composition of the present invention is a condensate of organoalkoxysilane represented by the general formula RSi(OR'):l, and has a weight average molecular weight in terms of polystyrene of 500 to 10,000. be.

In the above formula of organoalkoxysilane, R is an organic group having 1 to 8 carbon atoms, and Ro is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms.

If the number of carbon atoms in R and Ro is too large, the rate of hydrolysis described below will be extremely slow, and in some cases, hydrolysis will hardly proceed. As for the above R.

Alkyl groups such as methyl, ethyl, propyl, butyl; phenyl, tolyl, aryl such as xylyl; cycloalkyl such as cyclohexyl; and other γ-chloropropyl, vinyl, γ-glycidoxypropyl groups Bill group, T-methacryloyloxypropyl group, T-
Mercaptopropyl group, T-aminopropyl group, 3,4
-Epoxycyclohexyl group and the like. Examples of Ro include a methyl group, an ethyl group, a propyl group, a butyl group, and an acetyl group. Such organoalkoxysilanes include 1, for example, methyltrimethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, etc. Methoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, T-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane,
T-methacryloxytrimethoxysilane, γ-aminopropyltrimethoxysilane.

Examples include 3.4-epoxycyclohexylethyltrimethoxysilane. Preferably, methyltrimethoxysilane and/or methyltriethoxysilane are used. These organoalkokynesilanes can be used alone or in combination of two or more.

The above organoalkoxysilane is hydrolyzed and polycondensed to obtain organopolysiloxane, which is a component of the composition of the present invention. To prepare the above organopolysiloxane, 1. For example, first, the above organoalkoxysilane is prepared, and a water-soluble organic solvent is added thereto as necessary.

Examples of water-soluble organic solvents include alcohol solvents, cellosolve solvents, cellosolve acetate solvents, and glyme solvents. Water and, if necessary, an acid catalyst (described above) are added to this, and the mixture is heated at a temperature of about 20° C. or higher up to the reflux temperature for about 500 to about 20 hours to carry out a hydrolysis/polycondensation reaction.

Here, the hydrolysis and condensation of organoalkoxysilane is represented by a quadratic equation. From this equation, it can be seen that the theoretical amount of water required for hydrolysis is 1.5 times the mole of organoalkoxysilane.

R5i (OR') + +3tl□0mo: Amount R5i
(0)1) 3 + 3R' 01lnRSt(OH)
:+ Ri:〉(R3tO+,s)a + 1.5n
llzO By summarizing this equation, the following equation is obtained.

nRSi(OR')++1.5nHtO(R5iO
+, s), +3nR'OHThe above amount of water is usually about 0 per mole of alkoxy group of organoalkoxysilane.
．． 5-3 moles.

Preferably it is 0.8 to 1.5 mol. This ratio is approximately 0
．． If it is less than 5 moles, there will be a large amount of residual alkoxy groups.

The adhesion and hardness of the coating film to the substrate decrease. moreover,
It is not practical because it requires high temperature and long time when baking and curing the coating film. On the other hand, if the blending ratio exceeds about 3 moles, excess water will be present in the two reaction solutions, resulting in poor solution stability. What is the molecular weight of the product obtained by such hydrolysis/polycondensation?

About 500 to about 10,000. Preferably about 500 to about 5
,000. 9 Here, the molecular weight is a value calculated using a polystyrene conversion method using gel permeation chromatography. When the above molecular weight is less than about 500, the resulting paint has a high silanol content.

Therefore, if a thick coating film is formed using this paint, cracks are likely to occur. Furthermore, since silanol has high activity, when mixed with the surface-modified colloidal silica, the polymerization reaction progresses and gelation is likely to occur.

Lack of storage stability. On the other hand, if the molecular weight exceeds about 10,000, the silanol content is low, so the reactivity is low and it takes a long time to form a coating, which is not practical.

The composition of the present invention is obtained by blending the surface-modified colloidal silica and the organopolysiloxane. The blending ratio is 30 to 90% by weight, preferably 50 to 80% by weight of 1-surface modified colloidal silica in terms of total solid content.
The organopolysiloxane content ranges from 70 to 10% by weight, preferably from 50 to 20% by weight. When the organopolysiloxane content is less than 10% by weight, cranks are likely to occur in the coating film. Furthermore, because the adhesion of the coating film to the base material is poor,
Poor water resistance and weather resistance. On the other hand, if it exceeds 70% by weight, it will be difficult to form a thick coating film.

The composition of the present invention further contains various additives as necessary. For example, in addition to the above-mentioned surface-modified colloidal silica and organopolysiloxane, a 1TR additive or a coloring pigment can be added for use as a colored enamel, or an appropriate filler can be added to create a rust-preventing film, an electrically insulating film, etc. It can also be used as a paint for forming heat emitting films, conductive films, etc. In addition to this, additives include various surfactants, silane coupling agents, chikan coupling agents, polyamines, alkali metal salts, organometallic compounds,
Heterocyclic compounds containing nitrogen atoms, various metal alkoxides,
Examples include various conventionally known additives such as aluminum compounds such as aluminum acetylacetonate and dyes.

The coating composition containing the above-mentioned surface-modified colloidal silica, -organopolysiloxane, and various additives as necessary is diluted or concentrated with an organic solvent as appropriate to adjust the solid content before storage or use. Ru.

A desired coating film is formed by coating and curing a coating material containing the composition of the present invention on various substrates.

Substrates that may be used include metals, ceramics, cement, glass, plastics, paper, fibers, and the like. The solid content in the resulting paint has sufficient performance as an inorganic binder for the paint, so even when the paint does not contain the above additives and is directly applied to the surface to be painted and cured, it remains relatively thick at 5 to 20 μm. A covering layer is formed. The curing of the paint is about 120-200°C and 5-60°C.
It is possible to form a relatively thick coating film without cracking or peeling during curing. The coating film obtained from the paint is transparent if it does not contain additives such as pigments, and unlike conventional paints, the coating film does not turn white due to gelation of silica particles. In paints containing extender pigments or colored pigments, it is possible to add a large amount of pigment to form a coating film with a thickness of 30 μm or more without causing cracking or peeling.

The composition of the present invention comprises a surface-modified colloidal silica as described above and an organopolysiloxane.

Silica particle surface of surface modified colloidal silica.

Coated with a film of alkoxysilane compound condensate.

The acid silica particles and the coating film are bonded through stable siloxane bonds. Silanol groups are present on the surface of such modified silica particles resulting from a hydrolysis reaction when the particles are modified using an alkoxysilane compound. Similarly, the above organopolysiloxane also has silanol groups resulting from a hydrolysis reaction. By mixing the two, these silanol groups quickly react to form a condensate of silica particles and polysiloxane, resulting in a stable paint mixture. Since the silica particles are coated with a condensate of an alkoxysilane compound and furthermore, polysiloxane is interposed between the silica particles, the paint containing the composition of the present invention can be coated with a condensate of an alkoxysilane compound. Also, silica particles do not aggregate or gel during storage. When a coating material containing the composition of the present invention is applied to a substrate and cured by heating, a uniform, glossy coating film is formed on the surface of the substrate. Since the silica particles are uniformly dispersed in the paint, the silica particles do not gel and cause unevenness on the paint film. Since the silica particles are strongly bonded to the organopolysiloxane, the coating film does not shrink or crack during curing. The adhesion between the coating film and the base material is also good. As described above, by using the coating composition of the present invention, a coating film having gloss, high hardness, and excellent heat resistance, weather resistance, chemical resistance, etc. can be formed.

(Example) The present invention will be explained below with reference to Examples. In the examples, all parts are by weight.

11. (a) Preparation of surface-modified colloidal silica: In a reaction vessel equipped with a reflux condenser and a stirrer, 50 parts of methyltrimethoxysilane and methanol silica sol (manufactured by Nissan Chemical Industries, Ltd., solid content concentration 30%) were added. 330 parts 1 and 15 parts of water were charged, heated at 60°C with stirring, and reacted for about 2 hours. This was then cooled to room temperature to obtain surface-modified colloidal silica.

(b) Preparation of polysiloxane: In a separate reaction vessel equipped with a reflux condenser and a stirrer, 100 parts of methyltrimethoxysilane was charged and heated to 60"C with stirring. To this was added 40 g of water. , 60
After reacting at °C for about 5 hours, the mixture was cooled to room temperature to obtain an organopolysiloxane having a weight average molecular weight of about 3,000. The molecular weight was measured by a polystyrene conversion method using gel permeation chromatography.

(C) Preparation of coating composition: surface-modified colloidal silica obtained in section (a) and (b)
A coating composition A was obtained by mixing with the organopolysiloxane obtained in Section 3.

(d) Evaluation of coating composition: The coating composition obtained in section (C) was evaluated on the following items. The composition of the paint and the obtained results are shown in Tables 1 and 2, respectively, along with the evaluation results of the coating paint compositions obtained in Examples 2 to 5 and Comparative Examples 1 to 3, which will be described later.
Shown below.

[Storage Stability 1 Place the coating composition in a sealed container,
After being left at 30''C for 3 months, the increase in viscosity of the first composition and the presence or absence of gelation were examined.

For the following items, the coating composition was applied onto a cold-rolled stainless steel plate (JIS G43055O3-CP) using a spray device so that the dry coating film had a thickness of 10 μm. Heat this at 150°C for 30 minutes.

The obtained cured coating film was evaluated.

[Coating Film Appearance 1 Surface condition was evaluated by visual observation 9 [Adhesion] Evaluation was made using JIS K5400 substrate opening.

[Hardness] Evaluation was made by JIS K5400 pencil hardness.

[Heat resistance] The state was observed after being placed in an oven at 400°C for 16 hours.

[Solvent Resistance 1 Gauze was soaked in toluene, and the coating film was rubbed 30 times and the condition was observed.

A coating composition BE was obtained in the same manner as in Example 1 using the composition and reaction conditions shown in Table 1. The composition and evaluation results of the obtained coating composition are shown in Tables 1 and 2, respectively.

Coating composition F-H was obtained in the same manner as in Example 1 using the composition and reaction conditions shown in Table 1. The composition and evaluation results of the obtained coating composition are shown in Tables 1 and 2, respectively.

(Left below) 00 parts of Al of the coating composition obtained in Example 1 of Group 11 was used as a binder, and titanium oxide (manufactured by Ishiya Sangyo ■, Tybake R-380) was used as a binder.
) 30 parts and dispersed in a sand mill for 1 hour,
A coating composition I was obtained.

Next, the obtained coating composition I was applied onto a cold rolled stainless steel plate (JIS G43055O3-CP) using a spray device so that the dry coating film was 30 μm,
A cured coating was formed by heating at 150°C for 30 minutes.

In addition to the evaluation items shown in Example 1, these cured coating films were evaluated on the following items. The results are shown together with the evaluation results of coating compositions obtained in Examples 7 to IO and Comparative Examples 4 to 6, which will be described later.

It is shown in Table 3.

[Gloss] Measurement was performed according to JIS) 14001.

[The state of the boiling water resistance 1-coated stainless steel plate was observed after it was immersed in boiling water at 100°C for 24 hours.

[Drop 1 m of acid-resistant 15% sulfuric acid aqueous solution onto the coating film.

After being left undisturbed for one day in a petri dish with a lid, it was washed with water and its condition was observed.

[Alkali Resistance] 1 d of 1% aqueous sodium hydroxide solution was dropped onto the coating film, and after standing in a 1M petri dish for one day, it was washed with water and the condition was observed.

[Weather Resistance] An irradiation test was conducted for 3,000 hours using a weatherometer according to JIS K 5400, and the condition was observed.

A coating composition was prepared in the same manner as in Example 6, except that the coating composition B-E prepared in Examples 2 to 5 was used instead of the coating composition A published by Chisusemasu Uni. J to M were obtained and evaluated in the same manner. The results are shown in Table 3.

Example 6 except that coating compositions F-H prepared in Comparative Examples 1 to 3 were used in place of coating composition A.
Coating compositions N to P were obtained in the same manner as above, and evaluated in the same manner. The results are shown in Table 3.

(Left below) (Effects of the Invention) According to the present invention, a silicone-based coating that can easily form a coating film with excellent properties on the surface of a metal or ceramic substrate and has excellent storage stability. A coating composition is provided for use. The coating film obtained using the coating paint obtained by the powder coating method has high hardness, excellent scratch resistance, gloss, and has excellent heat resistance, weather resistance, water resistance, chemical resistance, etc. Excellent scratching. In particular, it maintains high gloss even when left at high temperatures or outdoors, and does not discolor or deteriorate.
It has excellent properties not found in conventional silicone coating paints. Therefore, for example, it can be advantageously used as a paint for coating exterior wall materials exposed to sunlight, equipment used under high-temperature conditions, building materials that require aesthetic appeal, and the like.

that's all

Claims (1)

[Claims] 1. A coating composition containing a surface-modified colloidal silica and an organopolysiloxane, wherein the surface-modified colloidal silica has two or more alkoxy groups ( Surface modification with alkoxysilane compounds having 1 to 8 carbon atoms) and/or alkoxysilane hypocondensates having 2 or more alkoxy groups in the molecule (having 1 to 8 carbon atoms) colloidal silica comprising silica particles; and the organopolysiloxane has the general formula RSi(OR')
A condensate of organoalkoxysilane represented by _3 (where R is an organic group having 1 to 8 carbon atoms, and R' is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms). and the weight average molecular weight in terms of polystyrene is 50.
0 to 10,000. Coating composition. 2. The surface-modified silica particles have a content of 30 to 30% in terms of total solid content.
The coating composition according to claim 1, wherein the organopolysiloxane is contained in an amount of 70 to 10% by weight calculated as a total solid content.