Coating Composition and Method of its Application

Abstract

The invention relates to a coating composition, especially to a coating composition intended for thermal insulation of hot metals, which contains an aqueous solution of silicate and which consists of the first layer containing 35 to 71 volume percent of hollow glass spheres, 26 to 62 volume percent of an aqueous solution of potassium silicate, 1 to 3 volume percent of an adhesive additive, and 0.1 volume percent of a water glass stabilizer, and of at least one second layer containing 71 to 84.6 volume percent of hollow glass spheres, 9 to 22.6 volume percent of an aqueous solution of potassium silicate, 0.2 to 0.3 volume percent of an adhesive additive, 0.1 volume percent of a water glass stabilizer, 2 to 3 volume percent of cut glass fibres, and 1.7 to 3 volume percent of a styrene-acrylate dispersion. Method of application of the coating composition, especially method of application of the coating composition which consists of at least one layer containing an aqueous solution of silicate according to which, as the first step, the first layer containing 35 to 71 volume percent of hollow glass spheres, 26 to 62 volume percent of an aqueous solution of potassium silicate, 1 to 3 volume percent of an adhesive additive, and 0.1 volume percent of a water glass stabilizer is applied and then the second layer containing 71 to 84.6 volume percent of hollow glass spheres, 9 to 22.6 volume percent of an aqueous solution of potassium silicate, 0.2 to 0.3 volume percent of an adhesive additive, 0.1 volume percent of a water glass stabilizer, 2 to 3 volume percent of cut glass fibres, and 1.7 to 3 volume percent of a styrene-acrylate dispersion is applied onto the first layer.

Claims

1. A coating composition intended for thermal insulation of hot metals, comprising an aqueous solution of silicate comprising a first layer comprising 35 to 71 volume percent of hollow glass spheres, 26 to 62 volume percent of an aqueous solution of potassium silicate, 1 to 3 volume percent of an adhesive additive, and 0.1 volume percent of water glass stabilizer, and at least one second layer comprising 71 to 84.6 volume percent of hollow glass spheres, 9 to 22.6 volume percent of an aqueous solution of potassium silicate, 0.2 to 0.3 volume percent of an adhesive additive, 0.1 volume percent of water glass stabilizer, 2 to 3 volume percent of cut glass fibers, and 1.7 to 3 volume percent of a styrene-acrylate dispersion.

2. The coating composition according to claim 1, wherein the first layer and second layer further comprise 1.8 to 7.5 volume percent of water.

3. The coating composition according to claim 1, wherein the first layer and second layer further comprise 0.1 to 0.4 volume percent of carbon black.

4. The coating composition according to claim 1, wherein the size of the hollow glass spheres ranges from 0.05 to 0.08 mm.

5. The coating composition according to claim 1, wherein the adhesive additive is triethanolamine.

6. The coating composition according to claim 1, wherein the water glass stabilizer is hydrophilic alkoxyle alkyl ammonia salt.

7. The coating composition according to claim 1, wherein the density of the aqueous solution of potassium silicate ranges from 1230 to 1250 kg/m.sup.3.

8. The coating composition according to claim 1, wherein the silicon-dioxide-to-potassium-oxide molar weight ratio in the aqueous solution of potassium silicate ranges from 3.8 to 4.1.

9. The coating composition according to claim 1, wherein the hollow glass spheres are made of such a material that comprises 70 to 80 weight percent of silicon dioxide, 3 to 8 weight percent of sodium oxide, 8 to 16 weight percent of calcium oxide, and 2 to 6 weight percent of boron oxide.

10. The coating composition according to claim 1, wherein the specific gravity of the hollow glass spheres ranges from 0.18 to 0.22 g/cm.sup.3.

11. The coating composition according to claim 1, wherein the cut glass fibers are made of alkaline zirconium silicate.

12. The coating composition according to claim 1, wherein the length of the cut glass fibers ranges from 4 to 10 mm and their diameter ranges from 0.01 to 0.02 mm.

13. A method of application of a coating composition comprising at least one layer comprising an aqueous solution of silicate, wherein as the first step, the first layer comprising 35 to 71 volume percent of the hollow glass spheres, 26 to 62 volume percent of the aqueous solution of potassium silicate, 1 to 3 volume percent of the adhesive additive, and 0.1 volume percent of water glass stabilizer, is applied onto the underlying surface, and then a second layer comprising 71 to 84.6 volume percent of the hollow glass spheres, 9 to 22.6 volume percent of the aqueous solution of potassium silicate, 0.2 to 0.3 volume percent of the adhesive additive, 0.1 volume percent of the water glass stabilizer, 2 to 3 volume percent of the cut glass fibers, and 1.7 to 3 volume percent of a styrene-acrylate dispersion is applied onto the first layer.

14. The method of application of the coating composition according to claim 13, wherein the second layer is applied onto the first layer not earlier than after 24 hours.

15. The method of application of the coating composition according to claim 13, wherein the first layer and second layer are then heated up to the temperature of 100° C. to 200° C.

16. The method of application of the coating composition according to claim 14, wherein the first layer and second layer are then heated up to the temperature of 100° C. to 200° C. not earlier than after 24 hours.

Description

EXAMPLES OF THE PERFORMANCE OF THE INVENTION

Example 1

[0026] The coating composition for thermal insulation of hot metals consists of the first layer applied in the thickness of 2 millimetres which contains 48 volume percent of hollow glass spheres, 46.3 volume percent of an aqueous solution of potassium silicate, 1.6 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of a water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 3.8 volume percent of water, and 0.2 volume percent of carbon black, and of the second 10 millimetre thick layer arranged (applied) on the top of the first layer. The second layer contains 74 volume percent of hollow glass spheres, 15 volume percent of aqueous solution of potassium silicate, 0.2 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of a water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 2 volume percent of cut glass fibres, 2 volume percent of a styrene-acrylate dispersion, 6.5 volume percent of water, and 0.2 volume percent of carbon black.

[0027] Hydrophilic alkoxyle alkyl ammonia salts in the form of 98-percent aqueous solution of N,N,N′,N′-Tetrakis (2-hydroxypropyl) ethylene diamine are used as a water glass stabilizer.

[0028] The size of the hollow glass spheres is 0.065 mm.

[0029] The density of the aqueous solution of potassium silicate is 1240 kg/m.sup.3 and the silicon-dioxide-to-potassium-oxide molar weight ratio is 3.9.

[0030] The specific gravity of the hollow glass spheres is 0.2 g/cm.sup.3 and the spheres are made of such a material that contains 75 weight percent of silicon dioxide, 6 weight percent of sodium oxide, 15 weight percent of calcium oxide, and 4 weight percent of boron oxide.

[0031] The length of the cut glass fibres is 6 mm, their diameter is 0.015 mm and they are made of alkaline zirconium silicate.

[0032] The aforementioned coating composition is to be applied as follows: As the first step, the first layer is applied onto a clean surface. The first layer contains 48 volume percent of hollow glass spheres; 46.3 volume percent of aqueous solution of potassium silicate, 1.6 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 3.8 volume percent of water, and 0.2 volume percent of carbon black. Then, 24 hours after the first layer being heated up to the temperature of 100° C. to 200° C. for 5 minutes and cooled down, the second layer is applied onto the first layer. The second layer contains 74 volume percent of hollow glass spheres, 15 volume percent of aqueous solution of potassium silicate, 0.2 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 2 volume percent of cut glass fibres, 2 volume percent of a styrene-acrylate dispersion, 6.5 volume percent of water, and 0.2 volume percent of carbon black.

[0033] Then, after 24 hours, both the layers are heated up to the temperature of 100° C. to 200° C. for the period of 5 minutes.

[0034] After both the layers cool down, the surface is to be ground and covered with a coat of paint.

Example 2

[0035] The coating composition for thermal insulation of hot metals consists of the first layer applied in the thickness of 1 millimetre which contains 65 volume percent of hollow glass spheres, 26.5 volume percent of an aqueous solution of potassium silicate, 2.2 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of a water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 5.8 volume percent of water, and 0.4 volume percent of carbon black, and of the second 5 millimetre thick layer arranged (applied) on the top of the first layer. The second layer contains 78 volume percent of hollow glass spheres, 9 volume percent of aqueous solution of potassium silicate, 0.2 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of a water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 2 volume percent of cut glass fibres, 3 volume percent of a styrene-acrylate dispersion, 7.5 volume percent of water, and 0.2 volume percent of carbon black.

[0036] Hydrophilic alkoxyle alkyl ammonia salts in the form of 98-percent aqueous solution of N,N,N′,N′-Tetrakis (2-hydroxypropyl) ethylene diamine are used as a water glass stabilizer.

[0037] The size of the hollow glass spheres is 0.065 mm.

[0038] The density of the aqueous solution of potassium silicate is 1230 kg/m.sup.3 and the silicon-dioxide-to-potassium-oxide molar weight ratio is 3.8.

[0039] The specific gravity of the hollow glass spheres is 0.18 g/cm.sup.3 and the spheres are made of such a material that contains 75 weight percent of silicon dioxide, 6 weight percent of sodium oxide, 15 weight percent of calcium oxide, and 4 weight percent of boron oxide.

[0040] The length of the cut glass fibres is 4 mm and their diameter is 0.01 mm and they are made of alkaline zirconium silicate.

[0041] The aforementioned coating composition is to be applied as follows: As the first step, the first layer is applied onto a clean surface. The first layer contains 65 volume percent of hollow glass spheres, 26.5 volume percent of aqueous solution of potassium silicate, 2.2 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 5.8 volume percent of water, and 0.4 volume percent of carbon black. Then, 24 hours after the first layer being heated up to the temperature of 100° C. to 200° C. for 5 minutes and cooled down, the second layer is applied onto the first layer. The second layer contains 78 volume percent of hollow glass spheres, 9 volume percent of aqueous solution of potassium silicate, 0.2 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 2 volume percent of cut glass fibres, 3 volume percent of a styrene-acrylate dispersion, 7.5 volume percent of water, and 0.2 volume percent of carbon black.

[0042] Then, after 24 hours, both the layers are heated up to the temperature of 100° C. to 200° C. for the period of 5 minutes.

[0043] After both the layers cool down, the surface is to be ground and covered with a coat of paint.

Example 3

[0044] The coating composition for thermal insulation of hot metals consists of the first layer applied in the thickness of 3 millimetres which contains 35 volume percent of hollow glass spheres, 62 volume percent of an aqueous solution of potassium silicate, 1 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of a water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 1.8 volume percent of water, and 0.1 volume percent of carbon black, and of the second 10 millimetre thick layer arranged (applied) on the top of the first layer. The second layer contains 71 volume percent of hollow glass spheres, 18 volume percent of aqueous solution of potassium silicate, 0.3 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 3 volume percent of cut glass fibres, 1.7 volume percent of a styrene-acrylate dispersion, 5.5 volume percent of water, and 0.4 volume percent of carbon black.

[0045] Hydrophilic alkoxyle alkyl ammonia salts in the form of 98-percent aqueous solution of N,N,N′,N′-Tetrakis (2-hydroxypropyl) ethylene diamine are used as a water glass stabilizer.

[0046] The size of the hollow glass spheres is 0.065 mm.

[0047] The density of the aqueous solution of potassium silicate is 1250 kg/m.sup.3 and the silicon-dioxide-to-potassium-oxide molar weight ratio is 4.1.

[0048] The specific gravity of the hollow glass spheres is 0.18 g/cm.sup.3 and the spheres are made of such a material that contains 75 weight percent of silicon dioxide, 6 weight percent of sodium oxide, 15 weight percent of calcium oxide, and 4 weight percent of boron oxide.

[0049] The length of the cut glass fibres is 10 mm, their diameter is 0.02 mm and they are made of alkaline zirconium silicate.

[0050] The aforementioned coating composition is to be applied as follows: As the first step, the first layer is applied onto a clean surface. The first layer contains 35 volume percent of hollow glass spheres, 62 volume percent of aqueous solution of potassium silicate, 1 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 1.8 volume percent of water, and 0.1 volume percent of carbon black. Then, 24 hours after the first layer being heated up to the temperature of 100° C. to 200° C. for 5 minutes and cooled down, the second layer is applied onto the first layer. The second layer contains 71 volume percent of hollow glass spheres, 18 volume percent of aqueous solution of potassium silicate, 0.3 volume percent of an adhesive additive (triethanolamine), 0.1 volume percent of water glass stabilizer (hydrophilic alkoxyle alkyl ammonia salt), 3 volume percent of cut glass fibres, 1.7 volume percent of a styrene-acrylate dispersion, 5.5 volume percent of water, and 0.4 volume percent of carbon black.

[0051] Then, after 24 hours, both the layers are heated up to the temperature of 100° C. to 200° C. for the period of 5 minutes.

[0052] After both the layers cool down, the surface is to be ground and covered with a coat of paint.

INDUSTRIAL APPLICATION

[0053] The coating composition according to this invention can especially be used for thermal protection of hot metal surfaces, e.g. for thermal protection of surfaces of steam pipelines, flue pipes, furnaces, refrigeration plants, and heating, ventilation and air conditioning devices.