JPH04100864A - painted dishes - Google Patents

Abstract

PURPOSE:To obtain a coated plate with a highly heat-resistant and hard film formed thereon by baking a heat-resistant coating material comprising a polymetallocarbosilane, silicone resin, inorganic filler and alkali metal silicate on a metallic plate. CONSTITUTION:A coated plate is prepared by applying on a metallic plate a heat-resistant coating material comprising a polymetallo-carbosilane (A) (e.g. a reaction product of Ti or Zr with a polycarbosilane having a number-average molecular weight of 200-1,000), a silicone resin (B) (e.g. methylphenylpolysiloxane), an inorganic filler (C) (e.g. silicon carbide powder) and an alkali metal silicate (D) (e.g. sodium metasilicate nonahydrate), followed by baking. The mixing proportion of the heat-resistant coating material is 10-900 pts., particularly 50-500 pts. component B, 10-900 pts., particularly 50-500 pts. component C and 5-100 pts., particularly 10-50 pts. component D based on 100 pts.wt. component A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coated plate having a heat-resistant and highly hard heat-resistant coating formed on its surface.

(Prior art and its problems) Japanese Patent Application Laid-Open No. 62-54768 discloses a heat-resistant paint in which polymetallocarbosilane, silicone resin, and inorganic filler are dispersed or dissolved in an organic solvent. The heat-resistant paint described in the above-mentioned publication can be baked in air, and the coating film obtained therefrom has the advantage of not only excellent heat resistance but also good corrosion resistance and impact resistance.

On the other hand, the coating film obtained by curing the polymetallocarbosilane by heating the paint described in the above publication at a temperature of 250 to 450'C, which is a temperature commonly used for baking, has a pencil hardness of 2H to 450'C.
3H, has a relatively low hardness, and has the problem of easily scratching the coating film. Therefore, the paint film obtained by baking this paint on a steak plate, for example, where surface hardness is required, is easily scratched by knives and forks, and the paint film is likely to peel off in a relatively short period of time.

(Technical means for explaining the problem) The present invention provides a coated plate in which a highly hard coating film is formed on a metal plate while maintaining the excellent heat resistance of a polymetallocarbosilane paint.

According to the present invention, a coated plate is provided in which a heat-resistant paint made of polymetallocarbosilane, a silicone resin, an inorganic filler, and an alkali metal silicate is baked onto a metal plate.

The polymetallocarbosilane used in the present invention is an organosilicon polymer known per se, for example, Japanese Patent Publication No. 61-4
No. 9335, No. 62-60414, No. 63-
It can be prepared according to the methods described in JP-A No. 37139 and JP-A No. 63-49691. The descriptions in these publications are incorporated herein by reference.

A typical method for producing polymetallocarbosilane is a method in which a polycarbosilane having a number average molecular weight of 200 to 1,000 is reacted with a titanium or zirconium alkoxide. Through this reaction, polycarbosilane is a crosslinked polymer with a number average molecular weight of 700 to 100°000, in which some of the silicon atoms in its skeleton are bonded via oxygen atoms with titanium atoms or zirconium atoms. A metallocarbosilane is obtained.

An organic solvent solution of the above-mentioned polymetallocarbosilane is commercially available as Tyrannocoat 0 varnish type from Ube Industries.

Specific examples of the silicone resin in the present invention include dimethylpolysiloxane, methylphenylpolysiloxane,
Pure silicone resins such as diphenylpolysiloxane, pure silicone resins, alkyd resins, polyester resins,
Examples include modified silicones reacted with modifying resins such as acrylic resins and epoxy resins.

The blending ratio of the silicone resin is 10 to 900 parts by weight, particularly 50 to 900 parts by weight, per 100 parts by weight of polymetallocarbosilane.
Preferably, it is 500 parts by weight. If the blending ratio of silicone resin is too small, the flexibility of the coating film will be reduced due to baking, and if the ratio is too high, the heat resistance and corrosion resistance of the coating film will be reduced due to baking.

The inorganic filler in the present invention is at least one selected from oxides, borides, phosphates, silicates (excluding alkali metal silicates), silicides, borides, nitrides, and carbides. is used. For example,
Magnesium, calcium, barium, titanium, zirconium, chromium, manganese, iron, cobalt, nickel,
Examples include oxides, carbides, nitrides, silicides and borides of copper, zinc, boron, aluminum and silicon, borates, phosphates and silicates of magnesium, calcium or zinc.

The blending ratio of the inorganic filler is polymetallocarbosilane 10
0 parts by weight, 10 to 900 parts by weight, especially 50 to 50 parts by weight
Preferably, it is 0 parts by weight. By incorporating an inorganic filler, the adhesion of the coating film to the substrate during baking is improved, but if the proportion of the inorganic filler is too high, the flexibility of the coating film decreases.

As the alkali metal silicate in the present invention, the formula
MzO・n5iOz HxHzO [In the formula, h is L1%
Na5K or NR4 (R is an alkyl group), n is 0
．． 5-4, and X is 0-10. ] Compounds represented by the following are generally used.

Specific examples thereof include sodium metasilicate nonahydrate, sodium orthosilicate hydrate, potassium metasilicate hydrate, and lithium metasilicate hydrate.

The blending ratio of the alkali metal silicate is 5 to 100 parts by weight, particularly 1 part by weight, per 100 parts by weight of polymetallocarbosilane.
It is preferably 0 to 50 parts by weight. If the blending ratio of alkali metal silicate is too small, the hardness of the paint film will not be sufficient, and even if the ratio is increased excessively, there is a limit to the increase in hardness, and conversely, the flexibility of the paint film will decrease. .

The above coating components in the present invention are used after being dispersed or dissolved in an organic solvent. Any organic solvent can be used as long as it is capable of dissolving polymetallocarbosilane and silicone resin. Specific examples include toluene, xylene, n-butanol, isobutanol, butyl acetate, mineral spirit, solvent naphtha, ethyl cellosolve, and cellosolve acetate.

The proportion of the organic solvent to be used varies depending on the type and blending proportion of the film-forming components, and can be appropriately determined by those skilled in the art in accordance with the disclosure of the present invention.

There are no particular restrictions on the material of the metal plate on which the heat-resistant paint is baked in in the present invention, but cast iron and stainless steel are usually used.

There is no particular restriction on the size of the metal plate, and various sizes can be used depending on the purpose of use.

The method of applying the heat-resistant paint to the metal mold plate according to the present invention includes known methods such as brush painting,
Painted by roll coating, spraying, dipping, etc.
It is then dried and baked.

The amount of heat-resistant paint applied is preferably 20 to 100 g/rrr. If the coating amount is too small, pinholes are likely to occur in the coating film, resulting in decreased corrosion resistance.

On the other hand, if the coating amount is excessively large, cracks are likely to occur in the coating film when the coating film is exposed to high temperatures or to cooling/heating cycles.

The baking temperature is preferably 150°C or higher, particularly 200°C or higher. If the baking temperature is too low, the polymetallocarbosilane, which is one of the paint components, will not be sufficiently cured, resulting in a decrease in the strength of the coating film and also in its impact resistance.

(Example) Examples and comparative examples are shown below. Unless otherwise specified in the examples, "%" and "parts" refer to "% by weight" and "parts by weight," respectively.

The pencil hardness of the formed coating film was measured according to JIS K 5400.

Furthermore, the heat resistance of the coating film was evaluated as follows.

That is, the object to be coated is held at 1000°C for 200 hours in an open air environment, then taken out from the open air and slowly cooled in the air. Then, a cross cut of 1 mm + pitch is made in the coating film with a cutter knife, and this area is covered with adhesive cellophane. A tape was applied, and after the tape was rapidly removed, the presence or absence of peeling of the paint film was examined. Heat-resistant "
It was rated as ``good'', and those in which peeling was observed even in some areas were rated as ``poor heat resistance''.

Example 1 100 parts of a 50% xylene solution of polytitanocarbosilane (Tyranocoat [F] varnish type, manufactured by Ube Industries, Ltd.),
50% xylene solution of methylphenylpolysiloxane (
A heat-resistant paint was prepared by mixing 100 parts of TSR-116 (manufactured by Toho Silicone Co., Ltd.), 100 parts of silicon carbide powder, 30 parts of sodium metasilicate nonahydrate, and 70 parts of xylene in a mixer.

Separately, a stainless steel plate (SOS 316L) with a thickness of 0.6 mm was degreased with acetone as a base material and then air-dried.

Approximately 30μ of the heat-resistant paint is applied to the base material using a spray gun.
The film was coated to a thickness of m, baked in an air oven at 300°C for 25 minutes, and then slowly cooled.

The pencil hardness of the formed coating film was 9H or higher.

Moreover, the heat resistance of this coating film was "good".

Example 2 Example 1 was repeated except that 30 parts of sodium orthosilicate hydrate was used instead of sodium metasilicate nonahydrate.

The pencil hardness of the resulting coating film is 9H or higher, and the heat resistance is "
It was "Good".

Comparative Example 1 Example I was repeated except that sodium metasilicate nonahydrate was not included.

The pencil hardness of the resulting coating film was 2H, and the heat resistance was "good".
Met.

Example 3 Example 1 was repeated except that 200 parts of silicon nitride powder was used instead of silicon carbide powder.

The pencil hardness of the resulting coating film is 9H or higher, and the heat resistance is [
It was a good J.

Example 4 Example I was repeated except that 50 parts of zirconium oxide powder was used instead of silicon carbide powder.

The pencil hardness of the resulting coating film is 9H or higher, and the heat resistance is "
It was "Good".

Claims (1)

[Claims] A painted plate in which a heat-resistant paint consisting of polymetallocarbosilane, silicone resin, inorganic filler, and alkali metal silicate is baked onto a metal plate.