SU685409A1 - Burn-on preventing coating - Google Patents

Description

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This invention relates to a foundry, in particular to compositions of nonstick coatings used primarily for metal molds,

A known nonstick coating for casting metal formicles, I-containing carbon black, refractory clay, water glass, primary target and sulphite liquor 1.

The disadvantage of this nonstick coating is the formation of soot and deposits on the surface of the chill mold due to the presence of liquid glass in the coating composition,

The closest to the described invention to the technical essence and the achieved result is a nonstick coating containing phthalocyanine; potassium binder - carboxymethylcellulose gel and water 2.

The disadvantage of this coating is its high gas content.

The aim of the invention is to reduce the gas-effect of the coating.

The goal is achieved by the fact that, as a binder, the coating contains polyacrylamide and, additionally, a non-ionic surfactant substance OP-7 (polyethylene glycol ether of alkylphenols with ethylene oxide number 7 in the following ratio of ingredients, wt.%:

Phthalocyanine potassium 2.5-3.5 Polyacrylamide 0.5-0.7

Non-ionic surfactant OP-70,04-0,07 Water Else

Potassium phthalocyanine is an intracomplex compound of tetrabenzotetrazoporphine with potassium. It is a separation agent that prevents sticking of the casting core to the casting.

Polyacrylamide (TU 7-04-01-72) is a high molecular weight compound, soluble in water, dissolving at a temperature of about 200 ° C in a nonstick coating, it is used as a continuous one.

Surfactant (OP-7 according to GOST 8422-57) is a polyethylene glycol ether of alkylphenols with an ethylene oxide number of 7; used as a wetting agent. When specified

the ratio of ingredients, the introduction of IIAB makes it possible to obtain a consistency of the coating that provides the conditions for the mechanization and automation of its application to the working surface of the chill mold.

Examples of compositions of nonstick coatings are given in table. one.

Table 1

As can be seen from Table 1, the composition of the coating 2 has the best properties.

An increase in the content of potassium phthalocyanine above 3.5% leads to an increase in newspaper capacity. Lowering the phthalocyanine content to less than 2.5% impairs its crumbly ability.

A polyacrylamide content of more than 0.7% leads to an increase in the viscosity of the coating, which makes it difficult to apply it to the chill mold. Lowering the polyacrylamide content to less than 0.5% reduces the consistency of the coating; however, the coating is uneven, leaking.

An increase in the OP-7 content of more than 0.06% results in increased foam formation, which affects the quality of the coating. The content of OP-7 less than 0.04% reduces the wetting ability of the coating.

1,003

120 Casting surface 0,820

Claims (1)

120 After 75 fillings on top of the table it can be seen that the proposed coating can withstand a greater number of fillings while maintaining the high quality of the surface of the castings. Invention Formula The nonstick coating contains potassium phthalocyanine, a binding agent and water, characterized by that. The preparation of the coating is as follows. The container with the mixer turned on is filled in with the calculated amount of polyacrylamide and water until the polyacrylamide is completely dissolved. Then, the calculated amount of surfactant OP-7 is added. After the OH-7 is completely dissolved, potassium phthalocyanine is added in small portions to the mixer after the potassium phthalocyanine is completely dispersed in the solution. The coating is applied with a spray on. The previously cleaned degreased first surface of the chill mold, heated to Data on the comparison of the known and proposed coatings on the quality of the surface of the castings are given in Table 2, whereby samples of aluminum alloy AK-BM-7 (grst 1583-73) are cast into a chill mold. The pouring temperature is 780-800 C. table 2 smooth, smooth, clean, without impregnations hnost castings of mat, hilly, interspersed with paint that, in order to reduce its gas-producing ability, as a binder, the coating contains polyacrylamide and additionally a non-ionic surfactant (polyethylene glycol ether of alkylphenols with ethylene oxide number 7) in the following ratio of ingredients, wt.%: Phthalocyanine potassium 2.5-3 i Polyacrylamide 05-07 Non-ionic superficiality. -T-tv "in" about "abouts about 04-0 07 Vop x Else. 6854096 ™ „„ information,; taken into account in the examination of the USSR Copyright Certificate of the USSR / ° UK Patent No. 1173022 5 cl. In 3 P, 1976.