JPH02228373A - Corrosion-resistant coating material - Google Patents

Abstract

PURPOSE:To prepare a corrosion-resistant coating material with an excellent heat resistance, i.e., an improved corrosion resistance after heating at a high temp., by compounding a specific resin contg. silicone with magnesium oxide and a paste of aluminum powder. CONSTITUTION:At least one resin selected from the group consisting of a polyborosiloxane resin having the main chain structure of formula I, a polycarbosilane resin having the main chain structure of formula II, a polysilastyrene resin having the main chain structure of formula III, a polysilazane resin having the main chain structure of formula IV, and a polytitanocarbosilane resin having the main chain structure of formula V is mixed with magnesium oxide and a paste of aluminum powder. The resulting mixture is dissolved or dispersed in a solvent to give a corrosion-resistant coating material. The coating material is applied to a muffler, a piping around the engine, etc., of an automobile, and baked at about 400 deg.C to form a corrosion- resistant coating film with an excellent heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a heat-resistant anticorrosive paint suitable for coating automobile mufflers, piping around engines, and the like.

(Prior Art) So-called metallic paints have been known as anticorrosive paints, which are made by adding paste aluminum powder or the like to organic thermosetting resins to improve the heat resistance and anticorrosion properties of the paints. Thermosetting resins used in such paints include polyester, polyurethane, melamine formaldehyde resin, etc. However, when heated at a high temperature of about 500°C, the paint film itself deteriorates, and the paint film itself deteriorates after heating. The corrosion resistance is significantly reduced, and when a salt spray test is performed, there is a problem in that rust occurs on the entire coating film.

(Issues to be solved by the invention) The present invention was made in response to the above-mentioned conventional circumstances, and it has sufficient heat resistance that the coating film does not deteriorate even when heated at a high temperature of about 500°C, and The purpose of the present invention is to provide an anticorrosion paint that significantly reduces the deterioration of anticorrosion properties.

(Means for Solving the Problem) The present invention provides (a) at least one selected from polyborosiloxane resin, polycarposilane resin, polysilastyrene resin, polytitanocarbosilane resin, and polysilazane resin; (b) An anticorrosion paint characterized by blending paste-like aluminum powder and (c) magnesium oxide.

In the present invention, by using the above-mentioned (a) and (b), it is possible to
It has excellent heat resistance that can withstand application in the high temperature range of 00 to 600℃, and when (c) is used in combination with this, it can withstand applications in the high temperature range of 500℃
Corrosion resistance after heating can be greatly improved by heating.

(a) The polyborosiloxane resin, polycarpodilane resin, polysilastyrene resin, polytitanocarbosilane resin, and polysilazane resin of the present invention has a main chain of Si, Ti, and B.
and O, N, etc., and organic groups such as methyl groups and phenyl groups are bonded to the side chains, and any known ones can be used, and their main skeletons are shown in Table 1. Further, these resins can be used alone or in combination.

(The following is a blank space) Table 1 Furthermore, in the present invention, a silicone resin can be used in combination with these resins. Silicone resins are more heat resistant than those in (a), but they are useful for modifying these resins when used in an amount of less than 50% by weight based on the total amount of resin.

These resins are usually fired under acid-free snow to form a non-oxide ceramic coating (SiC=B4C5・5i
sNa, TiC, etc.), and in the heating end region in the atmosphere, the organic groups of the chain are detached, ultimately forming an oxide-based ceramic coating, which provides a coating with excellent heat resistance. become.

As the pasty aluminum powder in the present invention, we use known powders that are paste-like at room temperature, such as pulverized aluminum powder that has been surface-treated with saturated 111j acid (stearic acid), etc., or one-finger type powder. can do. Specifically, there is Alpaste (trade name, manufactured by Toyo Aluminum Co., Ltd.) and the like.

In the present invention, (b) 10 to 100 parts by weight of paste-like aluminum powder, and (c) 2 to 50 parts by weight of magnesium oxide, per 100 parts by weight of the non-volatile resin (b) at 300°C for 1 hour. It is preferable to add weight #a, (b)
If the amount of the component is less than 10 parts by weight, the heat resistance will decrease;
If the weight part is exceeded, the surface of the coating film will become uneven and the appearance will deteriorate. Furthermore, if the amount of component (iii) is less than 2 parts by weight, the improvement in anticorrosion properties is almost negligible, and if it exceeds 60 parts by weight, the mechanical properties of the coating film will deteriorate.

The anticorrosive paint of the present invention is prepared by blending appropriate amounts of each of the components (a), (b), and (c), dissolving or dispersing the mixture in a diluent solvent such as N-methyl-2-pyrrolidone or xylene, and stirring with a stirrer. It can be obtained by The obtained paint can be applied to the surface of metal parts, etc. by a conventional method such as spray coating, dip coating, flow coating, or roll coating, and if finished at a temperature of about 400°C, it will form a heat-resistant anticorrosion coating. Can be done.

(Example) Examples of the present invention (explained below)

Examples 1 to 4 Each component was mixed in the formulation shown in the table and stirred with a mixer to produce the anticorrosive paint of the present invention. This was applied to a 5US304 plate, and then baked at 400° C. for 10 minutes to obtain a coating film with a thickness of 20 μm, which was used as a test piece. The obtained test piece was
After heating in the open for 24 hours at temperatures of 0°C, 500°C, and 600°C, a salt spray test was conducted in accordance with IIS K 5400, and the results are shown in the table.

Comparative Examples 1 and 2 Each component was mixed according to the formulation shown in the table, and test pieces were produced in the same manner as in Example 1, and tested in the same manner.

The results are shown in the table.

(Left below) Book 1...N-methyl-2-pyrrolidone? Non-volatile content of liquid a 2 to 5...Non-volatile content of xylene soluble iα 6...Leafing type book 7...◎ No rust formation observed ○ Slight rust formation ∆ Rust was observed on about half of the surface of the paint film. It is possible to significantly improve soil corrosion resistance later on.

Claims (1)

[Claims] (1) (a) At least one selected from polyborosiloxane resin, polycarpodilane resin, polysilastyrene resin, polytitanocarbosilane resin, and polysilazane resin, (b) paste-like aluminum powder, and (c) magnesium oxide. An anticorrosive paint characterized by being formulated with.