RU2260608C2 - Priming-enamel of aqueous dispersion anti-corrosive series "kronakril" - Google Patents

Abstract

FIELD: paint and varnish materials.

SUBSTANCE: invention relates to priming aqueous-dispersion compositions designated for protection metallic surfaces against corrosion in exploitation both under atmosphere conditions and subjected for effect of different liquids. Invention proposes anti-corrosive aqueous-dispersion priming-enamel comprising the following components, wt.-%: styrene-acrylic dispersion as a binding agent, 30-50; calcium molybdate phosphate as an anti-corrosive pigment in the following ratio of molybdate and phosphate ions from 1:0.01 to 1:100; color-forming pigment, 1-10; phosphate dispersing agent, 0.1-10; thickening agent, 0.05-0.2, and water, the balance. Applying calcium molybdate phosphate in priming-enamels provides the passivating activity in interaction 0f phosphate-molybdate ions with metallic backing of both ferrous and nonferrous metals and exhibits the additional protecting effect.

EFFECT: improved and valuable properties of compositions.

2 tbl

Description

The invention relates to paints and varnishes, in particular to primers, water-dispersion compositions intended for protection against corrosion of metal surfaces, which are operated under atmospheric conditions and are exposed to various liquids. It can be used as a primary primer, as well as an independent paint coating.

It is known to use as a water dispersion primer a composition comprising butadiene styrene carboxylate latex, a surfactant, phosphoric acid, hydroxyethyl cellulose, sodium polyphosphate and water [USSR Author's Certificate No. 1004432, MKI C 09 D 5/02, 1980].

The disadvantage of this composition is the low film strength and low anticorrosion properties of the coating.

Closest to the claimed invention and adopted as a prototype is a water-dispersion primer comprising latex of a styrene-butadiene copolymer, phosphoric acid, zinc-iron phosphate pigment, surfactant, red iron oxide pigment, hydroxyethyl cellulose, sodium polyphosphate M20, No. 6, Patent No. 40, Patent No. 40 [Water 6, Patent No. 6, [Water Patent No. 640] C 09 D 109/08, publ. 07/10/96].

This primer has increased (compared to No. 1004432) mechanical strength and slightly increased anticorrosion properties when exposed to water due to the additional introduction of zinc iron phosphate pigment into the phosphoric acid composition.

However, a primer of this composition has little resistance to the effects of mineral oil, alkali, a solution of NaCl, gasoline and other solvents.

The task of the invention is the creation of a water-dispersion primer-enamel with high resistance to static effects of the above liquids, which allows its effective use in the chemical, engineering and automotive industries.

The essence of the invention is to use, as an anticorrosion pigment, instead of orthophosphoric acid and zinc iron phosphate pigment, calcium molybdate phosphate, the molar ratio of molybdate and phosphate ions in it can be from 1: 0.01 to 1: 100.

The technical result of the use of calcium molybdate phosphate in a water-dispersion enamel primer is the formation of a phosphomolybdate film on the substrate under the influence of a corrosive medium, which causes passivation of the metal surface and, thus, has an additional protective effect.

Thus, the use of calcium molybdate phosphate in enamel primers provides a high passivating activity in the interaction of phosphate-molybdate ions with a metal substrate of both ferrous and non-ferrous metals, providing cathodic and anodic protection.

The primer-enamel, both the prototype and the claimed one, consists mainly of a binder, an anti-corrosion pigment, a color-forming pigment, a dispersant and a thickener, the rest is water, which is used as a solvent.

In the prototype, a latex of a styrene-butadiene copolymer is used as a binder; in the present invention, it is proposed to use a styrene-acrylic dispersion as such, which improves the hardness and elasticity of the coating. Qualitative signs of styrene acrylic dispersion are shown in table. 1. Its quantitative content in the composition of the primer-enamel is 30-50%, which is established as a result of research. This feature is distinctive from the prototype.

In the prototype, orthophosphoric acid and zinc iron phosphate pigment are used as an anti-corrosion pigment, in the present invention, as was justified above, calcium molybdate phosphate is used with its content in an enamel primer of 0.1-20% depending on the metal that is coated with this enamel primer .

In the prototype, the pigment used is a red iron oxide pigment that paints the primed surface in red-brown color. However, other color-forming pigments can be used in such enamel primers, for example: yellow iron oxide pigment, blue phthalocyanine pigment, chromium oxide, aluminum powder, etc., which, without changing the chemical effect on the metal coated with the primer-enamel, change only the color of the coating . Since the color of the primer-enamel may be different, it is advisable to apply the general term for all tinting pigments - color-forming pigment. Its (pigment) content in the primer-enamel is almost the same as in the prototype - 1-10%.

In the prototype, sodium polyphosphate is used as a dispersant, but in the same quality, for example, potassium polyphosphate, sodium or potassium pyrophosphate, sodium or potassium tripolyphosphate can be used. In the present invention, sodium polyphosphate or the other substances listed above fulfill the same dispersant function, however, their application limits (according to the results of research) can vary from 0.1 to 1.0% in the composition of an enamel primer. This feature is defined as a “phosphate dispersant”.

In the prototype, oxyethyl cellulose, which belongs to the group of cellulose esters, is used as a thickener. This group also includes: carboxymethyl cellulose, cellulose diacetate, cellulose acetate propionate, tylose, mesylose, but also polymers of acrylic and methacrylic acids or polyurethanes (polyhydroxy esters, wired with isocyanate groups) can be used, which are similar in effect to enamel primers therefore, the general term “thickener” is applicable to these substances, especially since its content in the enamel primer for all substances of this group — 0.05–0.2%, gives the achieved effect.

The rest in the proposed enamel primer is water, as a solvent.

An example implementation of this invention can serve as a method of obtaining a primer-enamel, carried out by the applicant.

Water, a thickener, a phosphate dispersant, and calcium molybdate phosphate are loaded into a container with a stirrer in a prescription amount with stirring, stirring for 25-30 minutes. Then the mixture is fed into a bead mill and dispersed until the milling degree of the wedge device is not more than 30 microns. The ground mixture is fed into the mixer and a prescription amount of styrene acrylic dispersion is added. After mixing for 20-30 minutes, a color-forming pigment is added to obtain the desired shade. Next, the primer-enamel is checked for quality indicators.

To compare the resistance to static effects of aggressive liquids were prepared compositions of primers-enamels according to the claimed invention and the composition of the primer according to the prototype. When determining the resistance of the film to the static effects of aggressive liquids, an enamel primer was applied to plates made of 08 KP steel, previously cleaned from rust and degreased with acetone. The resulting coating was cured at a temperature of 20 ± 2 ° C for 5 days, then tested.

The test data are summarized in table. 2, where items 1-18 of the compositions of the proposed enamel primer with different ratios of calcium phosphate molybdate, styrene acrylic dispersion, color-forming pigment, dispersant, thickener and water, and item 19, a primer prepared in accordance with the most corrosion-resistant primer composition- prototype.

Table 1 No. p / p Quality indicator Norm 1 Mass fraction of nonvolatile substances,%, not less than (ppm) 40 2 pH, not less 7.0 3 Mass fraction of residual monomer,%, no more 0.05 4 Resistance to mechanical stirring, rpm, no more 14000

table 2 No. p / p Calcium molybdate phosphate, wt.% Styrene acrylic dispersion, wt.% Color-forming pigment, wt.% Phosphate dispersant, wt.% Thickener, wt.% Water, wt.% The resistance of the film to the static effects of mineral oil, h, n / m The resistance of the film to the static effects of alkali 3% NaOH solution, h, n / m Film resistance to static action of 3% NaCl solution, h, n / m The resistance of the film to the static effects of water, h, n / m 1. 0.1 thirty 1,0 0.1 0.05 68.75 3 3 2 10 2. 0.1 thirty 10 1,0 0.2 58.7 3 3 2 10 3. 10 thirty 1,0 0.1 0.05 58.85 25 23 thirty 200 4. 10 thirty 10 1,0 0.2 48.8 25 23 thirty 200 5. twenty thirty 1,0 0.1 0.05 48.85 26 28 40 200 6. twenty thirty 10 1,0 0.2 38.8 26 28 40 200 7. 0.1 40 1,0 0.1 0.05 58.75 5 5 2 10 8. 0.1 40 10 1,0 0.2 48.7 5 5 2 10 9. 10 40 1,0 0.1 0.05 48.85 60 thirty fifty 250 10. 10 40 10 1,0 0.2 38.8 60 thirty fifty 250 eleven. twenty 40 1,0 0.1 0.05 38.85 60 thirty 55 280 12. twenty 40 10 1,0 0.2 28.8 60 thirty 55 280 thirteen. 0.1 fifty 1,0 0.1 0.05 48.75 5 5 2 12 14. 0.1 fifty 10 1,0 0.2 38.7 5 5 2 12 fifteen. 10 fifty 1,0 0.1 0.05 38.85 55 32 60 260 16. 10 fifty 10 1,0 0.2 28.8 55 32 60 260 17. twenty fifty 1,0 0.1 0.05 28.85 55 40 60 300 eighteen. twenty fifty 10 1,0 0.2 18.8 55 40 60 300 19. Prototype twenty 10 eighteen 72

Claims (1)

Primer-enamel water-dispersion anticorrosive, including a binder - styrene acrylic dispersion, anticorrosive pigment - calcium molybdate phosphate with a molar ratio of molybdate and phosphate ions from 1: 0.01 to 1: 100, color-forming pigment, phosphate dispersant, thickener and water when the following ratio of components, wt.%: Acrylic Dispersion 30-50 Calcium Molybdate Phosphate 0.1-20 Color-forming pigment 1-10 Dispersant 0.1-1.0 Thickener 0.05-0.2 Water Rest