RU2238288C1 - Enamel - Google Patents

Abstract

FIELD: protective coatings.

SUBSTANCE: invention is dealing with enamel designed for protective and decorative painting of various-nature surfaces and can find use for decorative anticorrosion protection of preliminarily sized surfaces of metal objects, including large-size ones. Enamel contains (i) 79.60-87.00% of film-forming component composed of partially saponified vinyl chloride/vinyl acetate copolymer (15%) in mixture of organic solvents consisted of butyl acetate, acetone, and toluene at ratio 1:2:5; (ii) 10.50-18.00% of mixed pigment containing titanium dioxide (9.10-10.30%), yellow iron oxide pigment (1.10-8.90%), red iron oxide pigment (0.10-0.30%), and carbon black (the balance); and (iii) 2.40-2.50% of fillers in the form of microtalc/silica powder mixture at ratio (90.0-92.0):(8.00-10.0). Enamel provides decorative effect characterized by light-beige gamma.

EFFECT: improved performance characteristics, in particular reduced viscosity and prolonged lifetime.

2 cl, 2 tbl

Description

The invention relates to the paint and varnish industry, in particular to paint and varnish compositions for forming decorative protective coatings of surfaces of various nature, and may find application for decorative anticorrosive protection of previously primed surfaces of metal products, including large ones.

Enamels are liquid paints and varnishes pigmented with highly concentrated microheterogeneous systems, one of the most important technological properties of which is viscosity, which allows the use of high-performance equipment for applying enamel to the surface of the product, the adhesion of the film, the resistance of the film formed on the surface of the product, and the decorative effect due to the purpose of the latter and their operating conditions.

Known enamel brand XC-527 (TU 2313-016-00206919-99), which is a suspension of pigments in a varnish based on hydroxyl-containing resins as a film-forming component.

The disadvantage of this composition is the limited color gamut, increased viscosity (40-100 s) and a short shelf life (12 hours at 5-15 ° C or 8 hours at 15-25 ° C), which creates inconvenience and limitations in its methods application.

Known enamel brand ХВ-518 (TU 2313-043-00204151-2001), which is a suspension of pigments in a solution of polyvinyl chloride chlorinated resin in a mixture of organic solvents with the addition of alkyd resin and plasticizer.

The disadvantage of this composition is the increased viscosity, insufficient film hardness.

The closest in technical essence are compositions for anticorrosion coatings, including a vinyl chloride-vinyl acetate copolymer, butyl acetate, acetone, toluene and a corrosion inhibitor - m - nitrobenzoate β - (- N-piperidino) propiononitrile (ed. Certificate of the USSR 1182057, publ. 30.09.09 .1985) or n-nitrobenzaldehyde (RF patent 2191792, publ. 27.10.2002).

The use of such compositions allows one to obtain only the corrosion resistance of the coated surface and cannot provide the necessary opacity of the surface coating and uniform decorative coloring of the substrate.

The objective of the invention is to expand the range of paints and varnishes that provide corrosion protection of metal surfaces while painting them, by creating a composition for coating surfaces that would paint surfaces in a light beige color scheme, would improve technological parameters of consumer properties, such as viscosity and expiration date.

The problem is solved by creating an enamel composition containing a film-forming component (A-15-0) - a 15% partially saponified copolymer of vinyl chloride with vinyl acetate in a mixture of organic solvents consisting of butyl acetate, acetone and toluene at a ratio of 1: 2: 5, mixed pigment containing in wt.% titanium dioxide 9.10-10.30, yellow iron oxide pigment 1.10-8.90, red iron oxide pigment 0.10-0.30 and carbon black - the rest, filler in the form of a mixture of microtalc and aerosil when they are contained in a mixture in wt.% 90.0-92.0 and 8.00-10.0, respectively, with the following eat a weight ratio of said components, wt.%:

Film-forming component 79.60-87.00

Blend pigment 10.50-18.00

Filler 2.40-2.50

As a film-forming component, a solution of a saponified copolymer of vinyl chloride with vinyl acetate of 15% concentration in a mixture of organic solvents containing butyl acetate, acetone, toluene in a ratio of 1: 2: 5 is used.

A mixture of microtalc and aerosil is used as a filler in the following ratio of components in this mixture, wt.%:

Microtalc 90.0-92.0

Aerosil 8.0-10.0

In order to expand the color range of light-protective decorative coatings, a mixed pigment is proposed containing a red iron oxide pigment, a yellow iron oxide pigment (for example, grade Zh-1 or Zh-2), titanium dioxide (for example, grade P-02), technical carbon (for example, grade P-803, K-354) in the following ratio of these components, wt.%:

Titanium dioxide 9.10-10.30

Yellow iron oxide

pigment 1.10-8.90

Red iron oxide

pigment 0.10-0.30

Carbon Black Else

The proposed enamel composition during coating formation is cured by chemical interaction of the hydroxyl groups of the vinyl chloride copolymer with vinyl acetate with the corresponding hardener groups. As the latter, various amines and isocyanates can be used. Experimental studies have shown that the hardest and most stable coating using the proposed enamel composition is formed using an isocyanate hardener with a mass fraction of isocyanate enamel groups of 16-17% of the total weight of the hardener. Such hardeners are Desmodur N75 hardeners, which is a solution of a mixture of 2,4-toluene diisocyanate and 1.6 hexamethylene diisocyanate, or polyisocyanate-biuret, taken for this composition in an amount of 4.8 or 5.6 wt.%.

Unlike known enamels, the proposed composition allows to increase the strength of the coating film, lower the viscosity, and thereby provide the possibility of applying the most technologically advanced method of applying enamel to the surface of the product, for example, the method of pneumatic spraying. In addition, the paintwork composition in the claimed ratio of components (film-forming solution, mixed pigment, fillers) can increase the shelf life (enamel life connected with the hardener) at a temperature of (20 ± 2) ° С up to 24 hours at the optimal value of viscosity index. Upon reaching a new technical result, a light beige coloring of the coated surfaces is simultaneously provided.

Enamel components are prepared by mixing in the usual manner, based on the calculated amounts of the components.

First, with stirring, a solution of a film-forming component is prepared (15% solution in a mixture of organic solvents of a saponified vinyl chloride-vinyl acetate copolymer), then, to obtain a pigment paste, a mixed pigment and fillers are added to a portion of the solution of a film-forming component, followed by dispersion of the resulting paste, passing it through a bead mill to achieve particle size dispersion of at least 45 microns. Then, the obtained pigment paste and the remainder of the 15% solution of the saponified vinyl chloride-vinyl acetate copolymer are loaded into the mixer. After stirring, the resulting enamel composition is filtered and packaged.

The invention can be illustrated by the following examples.

Example 1. The composition contains when reaching a beige color per 1000 parts by weight of mass: 15% solution of film-forming - 870 parts by weight; titanium dioxide - 91.4 wt.h .; yellow iron oxide pigment - 11.0 wt.h .; red iron oxide pigment - 1.5 wt.h .; carbon black - 0.1 wt.h .; microtalc - 23.4 wt.h. and Aerosil of the A-380 brand - 2.6 wt.h.

Examples of the composition of enamel to obtain other colors in wt.% Are presented in table 1. The ratio of enamel components to hardener is also given there.

Table 2 shows the properties of enamel and coating in comparison with the known decorative and protective enamels.

The properties of enamel and coatings were determined according to standard methods: determination of the conditional viscosity of enamel according to GOST 8420, determination of the amount of solvent and mass fraction of non-volatiles according to GOST 6989, determination of the drying speed of enamel according to GOST 19007, film elasticity in bending according to GOST 6806, coating hardness according to GOST 5233, film strength upon impact according to GOST 4765, adhesion of coatings according to GOST 15140, film resistance to static action of water according to GOST 9.403. Enamel and coating samples were prepared for testing in accordance with GOST 8832, Section 3.

The test results of the proposed enamel and coatings are shown in table 2, indicate the achievement of the objectives of the invention.

Claims (2)

1. Enamel containing a film-forming component (A-15-O) - 15% partially saponified copolymer of vinyl chloride with vinyl acetate in a mixture of organic solvents consisting of butyl acetate, acetone and toluene at a ratio of 1: 2: 5, a mixed pigment containing , wt.%: titanium dioxide 9.10-10.30, yellow iron oxide pigment 1.10-8.90, red iron oxide pigment 0.10-0.30 and carbon black - the rest, filler in the form of a mixture of microtalc and aerosil with their content in the mixture is 90.0-92.0 and 8.00-10.0 wt.%, respectively, in the following ratio of the named components ENTOV, wt.%: Film-forming component 79.60-87.00 Blend pigment 10.50-18.00 Filler 2.40-2.50 2. The enamel according to claim 1, characterized in that it further comprises an isocyanate hardener with a mass fraction of isocyanate groups equal to 16-17% of the total mass of hardener.