RU2165948C1 - Method of preparing refractory decorative coating - Google Patents

Abstract

FIELD: paint and varnish industry, more particularly preparation of refractory protective and decorative coatings on building and artistic products. SUBSTANCE: described is method of preparing refractory decorative coating by applying aqueous coloring composition based on phosphate binder and hardening during heat treatment operation. Aqueous coloring composition is paint which comprises, wt.%: alumophosphate or alumoborophosphate binder 32-40; alumina or mixture thereof with clays 5-57; inorganic pigment, 0-41; and water, the balance. Paint is applied onto damp or dried product to be further heat treated; paint coating is dried at 50-100 C for at least 5-20 minutes and paint layer fully hardens during heat treatment or burning product at temperatures from 400 to 1000 C. EFFECT: wide range of colors of (water, light-and atmosphere-resistant) coating. 2 cl, 1 tbl

Description

 The invention relates to the paint and varnish industry, in particular to the decorative and protective finish of building products, and can be used primarily for painting building or art products made of ceramics (brick, ceramic tile, etc.). In this case, the resulting decorative coating is refractory.

A known method of obtaining a decorative protective coating for coloring limestone-sand building materials, such as silicate brick, by applying to the product a water-based paint based on calcium-aluminum-chromophosphate binder in combination with pigments and fillers (titanium dioxide, alumina) and liquid sodium glass (SU, 1004430, C 09 D 1/00, 1981). The applied paint is dried at 10 - 15 ^o C for 30 - 40 minutes, and complete curing under these conditions occurs within a day. The resulting color coating is weather-resistant and durable, however, due to the curing time, this method is not technologically advanced especially in conditions of large production. In addition, the resulting coating is not refractory.

A known method of obtaining a decorative coating on building products, mainly for coloring silicate products by applying a paint composition based on alumina-phosphate binder, titanium dioxide, bentonite, inorganic pigment and silica waste from the production of alumina from alunite and subsequent drying of the coated product first at 18-20 ^o C and then for 1 hour at 100 - 120 ^o C (SU, 1426992 A1, C 09 D 1/00, 1986). The resulting coating has good physical and mechanical properties (adhesion, hardness, abrasion resistance), but requires special devices for heat treatment and is not sufficiently durable and refractory.

The closest in technical essence to the present invention is a known method for coating on building products by applying to the surface of the product paints based on alumina-phosphate binder, pigments and fillers, followed by heat treatment on an electric infrared stand at 150 - 170 ^o C for 10-15 minutes . In this case, the surface of the product is pre-activated with a 10% phosphoric acid solution before applying paint (SU, 834048, C 09 D 1/00, 1979). This method allows to obtain coatings with good physical and mechanical properties, however, it is technologically complicated, requires special equipment for heat treatment of the paint layer and does not allow to obtain a durable refractory coating.

 The technical task of the present invention is to simplify the technology for decorative coatings, improve its decorative and strength properties, ensure the durability and fire resistance of the coating.

The stated technical problem is achieved by the fact that in the method of obtaining a decorative coating on building products by applying to the surface of their aqueous coating composition based on a phosphate binder, heat treating the coating to cure it, paint containing in wt.% Is used as a coating composition:
aluminophosphate or aluminoborophosphate binder - 32 - 40
alumina or mixtures thereof with clays - 5 - 57
inorganic pigment - 0 - 41
water - the rest
the paint is applied to a raw or dried product to be subjected to subsequent heat treatment during its manufacture, the paint coating is dried at a temperature of 50-100 ^° C for at least 5-20 minutes, and the paint layer is completely cured during heat treatment or firing of the product in the range temperatures of 400 - 1000 ^o C. Inorganic pigment is preferably used in a paint composition in an amount of 2.8 - 41 wt.%.

Preliminary 5 - 20-minute drying of the paint layer at a temperature of 50 - 100 ^o C allows you to heat treatment or firing multi-row (multi-layer) large batches of painted ceramic products without damaging the paint coating.

To prepare the paint, an aluminophosphate binder (APS) with a density of 1.56 - 1.6 g / cm ³ or an aluminoborophosphate binder, for example, in the form of a concentrate (ABFC) according to TU 113-08-606-87 with a density of 1, is used as a phosphate binder. 56 - 1.63 g / cm ³ , pH not less than 0.1, mass fraction of phosphorus in terms of P ₂ O ₅ 36-39 wt.%, Aluminum in terms of Al ₂ O ₃ 8-9 wt.%, boron in terms of B ₂ O ₃ 1.3 - 2.0 wt.%.

 As an inorganic pigment in the paint, pigments are used that are lightfast and stable in a slightly acidic environment, such as iron minium, ocher, chromium oxide, cobalt blue, Dulevsky black and others, as well as ceramic waste, for example, ground brick or colored ceramic tiles.

Alumina, for example, grade G-00 with an Al ₂ O ₃ content _of at least 98% according to GOST 6912-74 or its mixture with kaolin or other white clays, is used as a filler.

 The combination in the method according to the invention of a phosphate paint of a simple composition, but with a certain qualitative and quantitative content of components, with certain selected conditions for the formation of a coating (applying paint to an unfired ceramic product, preliminary drying and heat treatment in the process of firing the product) together provide a very durable, refractory , matte protective and decorative coating with high adhesion.

 Formulations of paints of a wide range of colors have been developed: white, blue, blue, green, black, gray, brown, beige, etc.

 The coloring composition used in the method according to the invention is prepared as follows: the calculated amounts of powders (pre-ground and sieved, if necessary) of alumina (or its mixtures with kaolin, bentonite) and, if necessary, the pigment is mixed, then an appropriate amount of binder is added to this mixture ( APS, ABFK) and water and again mixed in a mechanical mixer or ball mill.

 The coatings obtained by this method are water resistant, light resistant, weather resistant, environmentally friendly and fireproof. Samples of coatings (coated products) obtained according to this invention, repeatedly washed with a hot brush with hot and cold water, as well as aged outdoors during the year, do not differ from control samples.

 This method is technological and allows to obtain durable coatings of good quality both in conditions of large production and in the manufacture of non-ferrous art ceramics.

 The following table provides specific embodiments of the invention.

Claims (2)

1. The method of obtaining a refractory decorative coating by applying to the surface of building products an aqueous coating composition based on a phosphate binder and curing during heat treatment, characterized in that as a water coating composition using paint containing wt.%:
Aluminophosphate or aluminoborphosphate binder - 32 - 40
Alumina or mixtures thereof with clays - 5 - 57
Inorganic pigment - 0 - 41
Water - Else
while the paint is applied to a raw or dried product to be further heat treated during its manufacture, the paint coating is dried at a temperature of 50 - 100 ^o C for at least 5 to 20 minutes, and the complete curing of the paint layer is carried out during heat treatment or firing of the product in the temperature range 400 - 1000 ^o C.  2. The method according to claim 1, characterized in that they use a paint composition containing inorganic pigment in an amount of 2.8 to 41 wt.%.

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