JPH0586331A - Heat resistant paint - Google Patents

Abstract

PURPOSE:To prepare the subject compsn. which forms a coating film excellent in heat resistance and adhesion to a fluororesin. CONSTITUTION:The objective compsn. is prepd. by dissolving or dispersing an organosilicon polymer selected from the group consisting of a polycarbosilane of formula I, a polycarbosilastyrene of formula II, and a polyborosiloxane, a silicone resin, an inorg. filler, and a sol. zirconium compd. in a mixture consisting of an arom. hydrocarbon solvent and an amine 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 coating composition which forms a coating film having excellent heat resistance and excellent adhesion to a fluororesin.

[0002]

[Prior Art and Problems] Japanese Patent Publication No. 60-46145
The publication discloses a coating composition in which polyborosiloxane, a silicone resin and an inorganic filler are dispersed or dissolved in an organic solvent. Further, Japanese Patent Application Laid-Open No. 62-235370 describes a coating in which polycarbosilane, a silicone resin and an inorganic filler are dispersed or dissolved in an organic solvent. The paints described in these publications have excellent heat resistance as compared with paints composed of a silicone resin and an inorganic filler. In Japanese Patent Laid-Open No. 2-282626, a ceramic layer in which polytitanocarbosilane which is a main component is ceramicized is provided on a base material such as a cooking surface of a high-temperature cooker or a wall surface of a heating chamber. And a layer containing a fluororesin powder is further provided thereon. When a fluororesin layer is formed on a coating film formed from the paint described in JP-B-60-46145 or JP-A-62-235370,
When a temperature change from room temperature to 300 to 500 ° C. is repeatedly applied as in a high temperature cooker, the fluororesin layer formed on the coating film comes off. The applicant has found that polycarbosilane, polycarbosilastyrene or polyborosiloxane, silicone resin, inorganic filler, and soluble zirconium compound are dispersed or dissolved in an organic solvent, and have excellent heat resistance and chemical resistance. Heat resistant paints have been proposed in Japanese Patent Application Nos. 2-218041 and 3-65724. Although various solvents are described as organic solvents in these specifications, there is no description about an amine solvent, and there is no description about the combined use of an aromatic hydrocarbon solvent and an amine solvent.

[0003]

[Technical Means for Solving the Problems] The present invention provides a heat resistant paint capable of forming a coating film having excellent heat resistance and excellent adhesion to a fluororesin layer. According to the present invention, an organosilicon polymer selected from the group consisting of polycarbosilane, polycarbosilastyrene and polyborosiloxane, a silicone resin, an inorganic filler, and a soluble zirconium compound are used as an aromatic hydrocarbon solvent. Provided is a heat resistant coating which is dispersed or dissolved in a mixed solvent with an amine solvent.

The polycarbosilane used in the present invention is mainly represented by the general formula (I).

[Chemical 1] (In the formula, R ¹ represents a hydrogen atom or an alkyl group, and R ² represents an alkyl group or a phenyl group.), Which is an organosilicon polymer comprising a carbosilane bond unit. Polycarbosilastyrene is an organosilicon polymer having a bond unit represented by the general formula (I) and a silastyrene bond unit represented by the following general formula (II), and having a partially crosslinked bond in some cases.

[Chemical 2] (In the formula, R ³ and R ⁴ each represent a hydrogen atom, an alkyl group or a phenyl group.) The above polycarbosilastyrene can be prepared, for example, according to the method described in JP-B-63-39617. it can. The description of this publication is referred to as part of the present specification. The polyborosiloxane can be prepared, for example, according to the method described in JP-B-58-4732. The number average molecular weight of the organosilicon polymer in the present invention is generally 1000 to 1
It is 0000. The organosilicon polymer may be used alone or in combination of two or more kinds.

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 preferably 10 to 900 parts by weight, and particularly preferably 50 to 500 parts by weight, per 100 parts by weight of the organosilicon polymer. 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.

At least one selected from oxides, borides, phosphates, silicates, suicides, borides, nitrides and carbides is used as the inorganic filler in the present invention. Examples thereof are magnesium, calcium, barium, titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, zinc, boron, aluminum, silicon oxides, carbides, nitrides, silicides, borides, lithium. , Sodium, potassium, magnesium, calcium or zinc borate, phosphate and silicate. The blending ratio of the inorganic filler is
It is preferably 10 to 900 parts by weight, and particularly preferably 50 to 500 parts by weight, per 100 parts by weight of the organosilicon polymer.
By blending the inorganic filler, the adhesion of the baked coating film to the substrate is improved, but if the blending ratio is too high, the flexibility of the coating film is reduced.

As the soluble zirconium compound in the present invention, an organic solvent or water-soluble zirconium compound is used. Examples of zirconium compounds soluble in organic solvents include zirconium alkoxides such as tetraethoxyzirconium, tetrobutoxyzirconium, ethyltriethoxyzirconium and dimethyldimethoxyzirconium; chelating agents such as acetylacetone, dialkylglyoximes, oxines and dithizone. And a zirconium chelate compound; a zirconium fatty acid salt such as zirconium octoate and zirconium stearate. Examples of water-soluble zirconium compounds include zirconium acetate, hydroxyzirconium, zirconium carbonate and the like. In the heat resistant coating composition of the present invention, an organic solvent is used as a medium, and therefore, of the soluble zirconium compounds, the zirconium compound soluble in the organic solvent is preferable. When using a water-soluble zirconium compound, it is preferable to mix it with other coating components as a solution in which a small amount of water is dissolved.

The proportion of the soluble zirconium compound is 0.1 to 50 per 100 parts by weight of the organosilicon polymer.
The amount is preferably 0.5 to 10 parts by weight. If the blending ratio of the zirconium compound is too small, the adhesion to the fluororesin will be reduced, and if the blending ratio of the zirconium compound is too large, the heat resistance of the organosilicon polymer will be impaired.

In the present invention, a mixed solvent of an aromatic hydrocarbon solvent and an amine solvent is used as the organic solvent. Specific examples of the aromatic hydrocarbon solvent include benzene,
Examples include toluene, xylene, and halides thereof. As the amine solvent, for example, the compounds described in "Solvent Handbook" issued by Sangyo Tosho Co., Ltd. can be used, and specific examples thereof include isopropylamine,
Examples thereof include dibutylamine, triamylamine, cyclohexylamine, diethanolamine and triethanolamine. Aromatic hydrocarbon solvent is 2 to 1 of amine solvent
It is preferable to use 0 times by weight. By using the amine solvent in combination with the aromatic hydrocarbon solvent, the adhesion of the coating film formed from the heat-resistant paint of the present invention to the fluororesin is improved. The proportion of the mixed solvent used is generally 20 to 500 parts by weight per 100 parts by weight of the film-forming component,
It can also be changed depending on the type and proportion of the coating film forming component.

The heat-resistant coating material of the present invention is applied to a non-metal base material such as a metal base material, an electric wire or ceramics, and a refractory brick by a means known per se such as brush coating, roll coater, spraying or dipping. It is dried and baked. The coating amount of the heat resistant coating is preferably ²⁰ to 100 g / m ² . If the coating amount is excessively small, pinholes are likely to occur in the coating film, and the corrosion resistance will decrease. 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 temperature or cold heat cycles. The baking temperature is preferably 150 ° C or higher, and particularly preferably 200 to 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 decrease and the impact resistance will decrease.
If the baking temperature is excessively high, the coating efficiency will decrease as described above. If the object to be coated is placed in a use environment of 150 ° C. or higher after coating with the paint, the baking process can be omitted.

[0011]

EXAMPLES Examples and comparative examples are shown below. Unless otherwise specified below, “%” and “part” refer to “% by weight” and “part by weight”, respectively. The adhesion between the coating film formed from the heat-resistant paint of the present invention and the fluororesin was measured as follows. JIS K5400 (6.1
5) According to the edge test described in the above, make 11 cuts in 2 mm increments in the vertical and horizontal directions on the coating film with a cutter knife, carefully attach cellophane tape to this part, and peel off suddenly 10 times. Repeatedly, the adhesiveness was judged from the peeled state of the coating film after the test. The evaluation result is 10 × 10 = 10
It is shown by some peeling in 0 eyes. That is, a / 100 means that a pieces were peeled off within 100 eyes.

Reference Example 1 (Synthesis of Polycarbosilane) 2.5 L of anhydrous xylene (liter) and 40 of sodium
After heating 0 g to the boiling point of xylene in a nitrogen stream, 1 L of dimethyldichlorosilane was added dropwise over 1 hour, and then 1
The mixture was heated under reflux for 0 hours to form a precipitate. The precipitate was filtered, washed with methanol and then with water to obtain 420 g of white powdery polydimethylsilane. This polydimethylsilane 2
To 50 g, 8.27 g of polyborodiphenylsiloxane was added and mixed, and the mixture was heated to 350 ° C. in a nitrogen stream in a 2 L quartz tube equipped with a reflux tube and polymerized for 6 hours to give polycarbosilane partially containing a siloxane bond. Got After allowing the product to cool, xylene was added to take out as a solution, which was filtered and then xylene was evaporated to obtain polycarbosilane having a number average molecular weight of 1500. Reference Example 2 (Synthesis of Polycarbosilastyrene) Equimolar amounts of dichloromethylsilane and dichloromethylphenylsilane were polymerized at 110 ° C. in a toluene solvent in the presence of a Na-dispersed catalyst to give a softening point of 86 to 94
C. polysilastyrene was obtained. This polysilastyrene is heat-treated under reduced pressure at 420 ° C. for 15 minutes to obtain a softening point of 175-175.
Polycarbosilastyrene having a number average molecular weight of 4,500 at 185 ° was obtained. Reference Example 3 (Synthesis of polyborosiloxane) 750 g of diphenyldichlorosilane and 124 g of boric acid
100 to 100 in n-butyl ether under a nitrogen gas atmosphere.
The mixture was heated at 120 ° C., and the produced white resinous material was further heated at 400 ° C. for 1 hour in vacuum to obtain 530 g of polyborodiphenyl siroquine.

Example 1 100 parts of a 50% xylene solution of the polycarbosilane obtained in Reference Example 1 and 50% of methylphenylpolysiloxane
Xylene solution (TSR-116 manufactured by Toshiba Silicone Co., Ltd.)
A heat resistant paint was prepared by mixing 100 parts, 100 parts of silicon carbide powder, 20 parts of tetrabutoxy zirconium, 5 parts of xylene, and 10 parts of trimethanolamine with a mixer. Separately from this, a stainless steel plate (SUS 316L) having a thickness of 0.6 mm as a substrate was degreased with acetone and then air-dried. The heat-resistant paint is applied to the base material with a spray gun to a thickness of about 30 μm, and the heat-resistant paint is applied in an air oven for 30 minutes.
After being baked and baked at 0 ° C. for 25 minutes, it was gradually cooled. Then, a top coat enamel paint made of polytetrafluoroethylene (Polyflon Enamel EK-5109BK, manufactured by Daikin Industries, Ltd.) having a film thickness of 20 to 30 μm is formed on the coating film.
The coating was spray-coated so that the coating composition had the same thickness as above, dried at 150 ° C. for 10 minutes, and then baked at 380 ° C. for 20 minutes. The adhesiveness of the coating film thus obtained was 3 to 8/100, and no chipping or cracking was observed in the cuts of the eyes.

Example 2 Example 1 was repeated except that 20 parts of zirconium octate was used instead of tetrabutoxy zirconium. The adhesion of the coating film was 5 to 10/100, and no breaks or cracks were observed at the corners.

Example 3 Instead of triethanolamine, triamylamine 10
Example 1 was repeated except that all parts were used. The adhesiveness of the coating film was 3 to 8/100, and no breaks or cracks were observed at the corners.

Comparative Example 1 Without using triethanolamine, only xylene was added to 1
Example 1 was repeated except that 5 parts were used. The adhesion of the coating film was 50 to 60/100, and more than half of the eyes were peeled off.

Example 1 except that the polycarbosilastyrene obtained in Reference Example 2 was used in place of the polycarbosilane.
Was repeated. The adhesion of the coating film is 3 to 8/100,
In addition, no chipping or cracking was observed at the break of the eye.

Example 5 Example 1 was repeated except that the polyborosiloxane obtained in Reference Example 3 was used in place of the polycarbosilane. The adhesion of the coating film was 3 to 8/100, and no chipping or cracking was observed in the cuts in the eyes.

[Chemical 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09D 183/04 PMT 8319-4J

Claims (1)

[Claims] 1. An organosilicon polymer selected from the group consisting of polycarbosilane, polycarbosilastyrene, and polyborosiloxane, a silicone resin, an inorganic filler, and a soluble zirconium compound are aromatic hydrocarbon solvents and amines. A heat resistant paint that is dispersed or dissolved in a mixed solvent with a system solvent.