JPH06212113A - Heat-resistant coating material - Google Patents

Abstract

PURPOSE:To provide a heat-resistant coating material which can give a coating film that is excellent in heat resistance, completely or markedly reduced in the formation of pinholes even at high temperatures, and resistant to the fixation of oily stains. CONSTITUTION:The coating material is prepared by dispersing or dissolving a polymetallocarbosilane, a silicone resin, an inorganic fuller, a powdery fluoroplastic, and glass frits of a softening point of 400-600 deg.C in an organic solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant paint which is resistant to use at high temperatures and is resistant to oil stains.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 62-54768 discloses a heat resistant coating in which a polymetallocarbosilane, a silicone resin and an inorganic filler are dispersed or dissolved in an organic solvent. The heat-resistant paint described in the above publication is capable of baking in air, and the coating film obtained from this exhibits excellent heat resistance and good corrosion resistance and impact resistance.
Have advantages.

[0003]

On the other hand, when a coating film formed from the coating material described in the above publication is exposed to a temperature of about 500 ° C. or higher, the volume shrinks as the polymetallocarbosilane is converted into an inorganic substance. , Pinholes reaching the base material may be generated. There is a problem to be solved in that the pinholes generated in this coating film limit its use in applications exposed to corrosive gases. Further, oil stains adhering to the surface of the coating film formed from the paint described in the above publication cannot be easily removed. Although this oil stain can be removed by using an alkaline liquid, the coating film does not have sufficient resistance to the alkaline liquid, so that there is a problem that the cleaning with the alkaline liquid cannot be repeated.

The object of the present invention is to provide a heat-resistant paint which has excellent heat resistance, is capable of significantly suppressing the occurrence of pinholes even at high temperatures, and is capable of giving a coating film to which oil stains are not easily fixed. Is to provide.

[0005]

To achieve the above object, according to the present invention, a polymetallocarbosilane, a silicone resin, an inorganic filler, a powdered fluororesin, and a softening point of 400 to 600 ° C. Provided is a heat-resistant coating material in which a glass frit is dispersed or dissolved in an organic solvent. Polymetallocarbosilane in the present invention is an organic silicon polymer known per se, for example,
Japanese Patent Publications No. 61-49335, No. 62-60414, No. 63-37139 and No. 63-49691.
It can be prepared according to the method described in the publication. The descriptions of these publications are referred to as part of the present specification. A typical production method of polymetallocarbosilane is a method of reacting polycarbosilane having a number average molecular weight of 200 to 1000 with an alkoxide of titanium or zirconium. By this reaction, polycarbosilane is a cross-linked polymer having a number average molecular weight of 700 to 100,000, in which a part of silicon atoms in the skeleton are bonded with titanium atoms or zirconium atoms through oxygen atoms. A metallocarbosilane is obtained. The organic solvent solution of the above polymetallocarbosilane was purchased from Ube Industries, Ltd. as Tyranno Coat ▲ R.
▼ Commercially available as a varnish type.

Specific examples of the silicone resin in the present invention include pure silicone resins such as dimethylpolysiloxane, methylphenylpolysiloxane and diphenylpolysiloxane, and conversion of pure silicone resin into alkyd resin, polyester resin, acrylic resin, epoxy resin and the like. The modified silicone reacted with the resin for use is exemplified. The mixing ratio of the silicone resin is polymetallocarbosilane 100.
10 to 900 parts by weight, especially 50 to 500 parts by weight
It is preferably part by weight. If the blending ratio of the silicone resin is too small, the flexibility of the baked coating film is lowered, and if the proportion is too high, the heat resistance and corrosion resistance of the baked coating film are lowered.

Specific examples of the fluororesin in the present invention include polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, ethylene / fluoroethylene alternating polymer. Coalescing,
Examples thereof include tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer and tetrafluoroethylene / perfluorosulfonyl fluoride vinyl ether copolymer. These fluororesins are described in, for example, Plastic Material Lecture 6 “Fluororesin” published by Nikkan Kogyo Shimbun. Among the above fluororesins, the tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer is excellent in heat resistance and releasability and has a low melt viscosity and is uniformly dispersed in a coating film formed from a coating material. It has excellent characteristics and is preferably used. The average particle size of the powdery fluororesin is generally 5 to 50 μm. The fluororesin imparts oil repellency to the coating film formed from the heat-resistant coating material of the present invention, so that oil stains are unlikely to adhere to the coating film and the adhered oil stains can be easily wiped off.

The mixing ratio of the fluororesin is preferably 10 to 200 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of polymetallocarbosilane. If the blending ratio of the fluororesin is too small, it is impossible to impart sufficient oil repellency to the coating film, and even if the blending ratio is excessively increased, the oil repellency of the coating film is not further improved industrially. has no meaning.

As the inorganic filler in the present invention, at least one selected from oxides, borides, phosphates, silicates, silicides, nitrides and carbides is used.
Examples include magnesium, calcium, barium, titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, zinc, boron, aluminum,
Silicon oxides, carbides, nitrides, silicides, borides, lithium, sodium, potassium, magnesium,
Examples include calcium or zinc borate, phosphate, and silicate. The mixing ratio of the inorganic filler is preferably 10 to 900 parts by weight, and particularly preferably 50 to 500 parts by weight, per 100 parts by weight of polymetallocarbosilane. If the blending ratio of the inorganic filler is too small, the adhesiveness of the coating film is lowered, and if the mixing ratio is too high, the flexibility of the coating film is lowered.

Examples of the glass which is a material for the glass frit having a softening point of 400 to 600 ° C. in the present invention include phosphate glass, borosilicate glass and lead glass. Among these, lead glass has a problem of toxicity. Therefore, heat-resistant paints containing the same should be refrained from use in consumer applications such as cooking utensils. On the other hand, since phosphate glass and borosilicate glass have no problem in toxicity, they can be used for various purposes including consumer use. The glass frit can be prepared by a method known per se in which molten glass is sprayed in water and quenched. The particle size of the glass frit is not particularly limited, but is generally 2 to 20 μm. The compounding ratio of the glass frit is preferably 10 to 200 parts by weight, and particularly preferably 20 to 100 parts by weight, based on 100 parts by weight of polymetallocarbosilane. If the compounding ratio of the glass frit is too small, the chemical resistance at high temperature, that is, the durability against corrosive gas, is not sufficient, and if the ratio is excessively increased, the flexibility of the coating film decreases. The softening point of the glass frit is 40
If the temperature is lower than 0 ° C, the glass frit is melted and aggregated during baking of the coating, so that the adhesion of the coating film is lowered and the mechanical strength is also lowered. When the softening point is higher than 600 ° C, the effect of preventing pinholes in the coating film becomes small.

As the organic solvent in the present invention, any solvent can be used as long as it has the ability to dissolve polymetallocarbosilane and silicone resin. Specific examples thereof include toluene, xylene, n-butanol, isobutanol, butyl acetate, mineral spirits, solvent naphtha, ethyl cellosolve, and cellosolve acetate. The proportion of the organic solvent used varies depending on the type and blending proportion of the film-forming component, but can be appropriately determined by those skilled in the art according to the disclosure of the present invention.

The heat-resistant paint of the present invention is applied to a metal base material or a non-metal base material such as ceramics or refractory bricks by a means known per se such as brush coating, roll coater, spraying or dipping, and then dried. And then baked. The coating amount of the heat resistant coating composition of the present invention is preferably ²⁰ to 100 g / m ² . If the coating amount is excessively small, pinholes are likely to occur in the coating film, resulting in poor 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 a high temperature or a thermal cycle.

The baking temperature is 150 ° C. or higher, especially 200
It is preferably ˜400 ° C. If the baking temperature is excessively low, the polymetallocarbosilane, which is one of the paint components, will not be sufficiently cured, and the strength of the coating film will be low and the impact resistance will be low. It should be noted that after painting the paint,
The baking process may be omitted when the product is placed in a use environment of 0 ° C. or higher.

[0014]

EFFECTS OF THE INVENTION The heat-resistant coating material of the present invention is applied to a desired solid surface and baked at 150 ° C. or higher to form a coating film that is resistant to use at high temperatures and is resistant to oil stains. Because it gives, cooking utensils that easily generate oil stains,
It is suitable for coating industrial parts and chemical equipment.

[0015]

EXAMPLES Examples and comparative examples will be shown below. Unless otherwise specified in the examples, “%” and “part” refer to “% by weight” and “part by weight”, respectively. The heat resistance of the coating film was evaluated as follows. 2 at 1000 ° C
After holding it in the air oven for 00 hours, take it out of the oven and slowly cool it in the air. Then, put a 1mm pitch cross-cut on the coating film with a cutter knife and attach an adhesive cellophane tape to this part, and sharpen it. The presence or absence of peeling of the coating film after peeling was examined. The heat resistance was “good” when the peeling of the coating film was not observed, and the heat resistance was “poor” when the peeling was partially observed.

The presence or absence of the pinhole-like peeled portion of the coating film was evaluated as follows. That is, the object to be coated is kept in an air oven at 1000 ° C. for 200 hours, then taken out of the oven and gradually cooled in the air, and then salt water is sprayed on the coating film for 200 hours to increase the corrosion state of the coating film by 50 times. It was observed under a microscope. Occurrence of rust and swelling of the coating film were observed in those with pinhole-like peeling.

The easiness of wiping off oil stains with the coating film (corrosion resistance to corrosion oil) was evaluated as follows. A few drops of salad oil of about 10 μm are dropped on the object to be coated, and 30
After holding in an air oven at 0 ° C. for 1 hour, it was taken out of the oven, gradually cooled in air, and then the appearance of the coating film was examined after removing stains with wet gauze. Corrosion-resistant oil stain resistance is “good” when no foreign matter is attached to the coating film and no trace of oil is observed. It was defined as "poor" due to edible oil contamination.

Example 1 50% xylene solution of polytitanocarbosilane (manufactured by Ube Industries, Ltd., Tyrannocoat® varnish type) 100
Parts, 100 parts of 50% xylene solution of methylphenyl polysiloxane (TSR-116 manufactured by Toshiba Silicone Co., Ltd.),
A heat resistant coating was prepared by mixing 100 parts of silicon carbide powder, 50 parts of phosphate glass frit (manufactured by Nippon Fellow, 01-4102M) and 50 parts of xylene with a mixer. Separately from this, a stainless steel plate (SUS 316L) having a thickness of 0.6 as a substrate was degreased with acetone and then air-dried. Approximately 30 μm with the spray gun on the above heat-resistant paint
It was applied to a thickness, baked and baked in an air oven at 300 ° C. for 25 minutes, and then gradually cooled. The heat resistance and corrosion oil stain resistance of the obtained coating film were “good”, and no pinhole-like peeling was observed.

Comparative Example 1 Phosphate glass frit (manufactured by Nippon Fellow, 01-41
02M) and no tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer was blended, Example 1 was repeated. The heat resistance of the obtained coating film is "good".
However, the corrosion oil stain resistance was "poor", and pinhole-like peeling was observed.

Example 2 Phosphate glass frit (manufactured by Nippon Fellow, 01-41)
Example 2 was repeated except that 50 parts of borosilicate glass frit (manufactured by Nippon Fellow, 12-3615) was used instead of 02M). The heat resistance and corrosion oil stain resistance of the obtained coating film were “good”, and no pinhole-like peeling was observed.

Claims (1)

[Claims] 1. A polymetallocarbosilane, a silicone resin, an inorganic filler, a powdery fluororesin, and a softening point of 4
A heat-resistant coating material, wherein glass frit having a temperature of 00 to 600 ° C. is dispersed or dissolved in an organic solvent.