RU2297431C1 - Method of preparing paint for protective and decorative coating of building structures - Google Patents

Abstract

FIELD: varnish-and-paint industry.

SUBSTANCE: invention relates to materials intended to form protective and decorative coatings on metals, concrete, wood, wood-based panels, and asbestos cement. Method of invention comprises: dispersing in water weatherproof pigments and fillers, foam suppressor, propylene glycol, and phosphate gel binder, namely reaction product of phosphoric acid solution and nepheline concentrate, which product is obtained by adding, at stirring, nepheline concentrate to phosphoric acid solution with 20-30% P₂O₅ to achieve pH 1.5 or to the same with 11% P₂O₅ to achieve pH 3.5 followed by settling resulting mixture for 0.5 h, separating water-insoluble particles, thermally treating the mixture at 80-100°C, cooling, washing, filtration on vacuum filter to 50-70% moisture, and removing water-soluble salt filtrate to obtain gel-like phosphate binder cake, to which decorative mica paste is added. Preparation of mica paste involves calcining mica waste, grinding 30% slurry of calcined mica waste in water at high-speed mode of mixing device provided with cutter, while adding antistatic in amount 0.5-1%, followed by washing and filtration, after which water-dispersed binder and acrylic thickener are added at high-speed mode of mixing device. Thus obtained paint possesses glossy silky luster at high content (45-55%) of latex binder or silky luster at low content (25-40%) of latex binder. Paint is resistant to moisture and pollution. Most heavily dust-forming components (silica, aluminum phosphate, micronized mica) are added to paint in the form of paste, which makes manufacture maximally safe. Paint film is elastic, nonshrinking, and resistant to pollution and large temperature changes.

EFFECT: improved performance characteristics of paint and coatings.

3 ex

Description

The invention relates to the technology of building materials intended for use as a protective and decorative coating for metal, concrete, wood, wood boards, asbestos cement.

A known composition for a protective and decorative coating, including wt.%: Phosphate binder - phosphoric acid (in terms of 100% H ₃ PO ₄ ) 2.5-10, zinc-containing compound - 0.7-2.8, filler and pigment - 18.0-39.5, surfactant 0.5-2.0, latex 35-58; one of the group of components: calcium oxide, calcium salt - 0.1-0.7 in CaO, one component from the group: boric acid, salt of boric acid - 0.05-3.2 in H ₃ BO ₃ 2.2-10 zinc-containing compound 0.7-2.8, filler and pigment 18.0-39.5, surfactant 0.5-2.0, latex 35-58; one of the group of components: calcium oxide, calcium-containing salt - 0.1-0.7 in CaO, one component from the group: boric acid, boric acid salt - 0.05-3.2 in H ₃ BO ₃ ; the rest of the water (SU No. 1715765. Cl. С04В 28/34, 02.29.1992).

The described composition has disadvantages: it is not sufficiently stable during storage, has a low water resistance, which limits its use for external coatings. In addition, to obtain such a composition requires expensive components.

A known composition for a protective and decorative coating, including, wt.%: Phosphate binder - 7-17; pigment - at least one of the components of the group: titanium dioxide, iron oxide, chromium oxide, spinel, a mixture of oxides from the group: chromium oxide, cobalt oxide, barium, zinc chromate, phthalocyanine pigment and a mixture of these components deposited on the filler - 3- 12; filler - at least one component from the group: silicon oxide, diatomite silica, andesitic dust, shungite, acidic slag, flotation slurry of phosphate or apatite ores, acid fly ash, barium sulfate, phosphogypsum and a mixture of these components - 4-30; surfactant 0.4-2.0; latex - 25-55; as well as at least one of the components from the group: aerosil, white soot, clay, hydrolyzed acrylate - 0.15-3.0, antifoam - 0.2-2.0; water is the rest. Surfactants and / or an antiseptic in the amount of 2-7% can also be introduced (RU No. 2097356, class C04B 28/34, 11/27/1997).

The known composition has several disadvantages. Firstly, an expensive phosphate-calcium-zinc nitrate borate reagent is used as a phosphate binder. Secondly, in addition to pigment, which uses expensive and often toxic components, an additional thixotropic additive, dispersant and other functional additives (aerosil, white soot, etc.) are introduced into the formulation. All this increases the number of components in the paint, and, accordingly, its price rises.

The closest analogue is a paint for protective and decorative coating of building structures, including phosphate binder, shell pigment, latex and water. As a phosphate binder, it contains the product of the interaction of phosphoric acid, nepheline concentrate and polyacrylamide at a weight ratio of 0.5: 1: 0.15, obtained by gradually adding to the solution of phosphoric acid with a concentration of 11% P ₂ O ₅ while stirring the nepheline concentrate until pH 3 , 5-4.0, keeping the mixture for 0.5 h, separating unopened nepheline particles and then adding polyacrylamide and stirring for 1 h, as the shell pigment and filler, the shell structure composition I, in which one of the following products plays the role of a carrier: finely dispersed mica powder, aluminum phosphate mixed with silica, calcium sulfate, fly ash of thermal stations, finely dispersed flotation sludges containing natural aluminum-iron-calcium silicates, and oxides serve as a shell iron or titanium in the following ratio of components in the paint, wt.%:

The specified phosphate binder 10-25 Shell composition 15-40 Latex 25-40 Water Rest

The phosphate binder incorporates silica gel, which acts as a dispersant and thickener, reducing the duration of dispersion and increasing the aggregate stability of the paint (RU No. 2179540, class C04B 41/67, C09D 1/00, 28.03.2000).

The composition has several disadvantages: the paint contains the product of the interaction of phosphoric acid and nepheline concentrate, including water-soluble salts of potassium and sodium. Liquid phosphate binder requires additional containers for storage. This disadvantage can be quite easily eliminated. The products of the interaction of phosphoric acid and nepheline concentrate, insoluble in water, form a gel-like precipitate, which is easily separated by filtration from the liquid component of the suspension. In this case, water-soluble salts pass into the filtrate and can be easily removed. The gel-like phosphate binder can be packaged in plastic bags and has an unlimited shelf life. This formulation is limited to specific pigments and does not always provide a high barrier protection despite the fact that it includes finely divided mica powder. Mica, ground in the traditional way, does not provide high barrier protection, since the particles are in the form of a cube.

The basis of the present invention was the task: to increase the dry residue in the paint, to improve the technical characteristics of the paint: water resistance, resistance to temperature extremes, weather resistance, light resistance, resistance to pollution.

The problem is achieved by the fact that decorative mica having a mirror surface and a thickness of less than 1 μm is added to the paint. In order not to damage the mirror surface of the flakes and increase the dry residue, decorative mica is introduced not at the stage of dispersion, but after, before applying the binder. Decorative mica is prepared as follows: mica waste, which is formed during the production of mica by pinching GOST 3028-78 or during the production of heat-resistant materials based on mica, is preliminarily calcined at a temperature of 700-800 ° C, then loaded into a container equipped with a mixing device with a mill and two speed modes, in the amount of 30 wt.%. Hot water is pre-poured into the container at a rate of 69-70 wt.%, An antistatic agent of 0.5-1 wt.% Is introduced. The mixing device is transferred to a high-speed mode of operation and stirred for 7-8 hours. Then the mixer is transferred to a low-speed operation mode, the resulting material is diluted with water and filtration is carried out with washing. Then make a colorful batch. Hot water is poured into the dissolver 15-30 wt.%, With stirring at a low speed mode of the stirring device, a gel phosphate binder is loaded, calculated on a dry residue of 0.5-4 wt.%, Weather-resistant pigments and fillers 20-40 wt.%, Antifoam 0.1-0.5 wt.%, Propylene glycol 1-2 wt.% And the mixing device is transferred to high speed mode. Mixing is carried out until a pigment milling of 10 μm is obtained. Then load the paste decorative mica in terms of dry residue of 2-10 wt.%. After 20-30 minutes, after the mica is evenly distributed in the composition of the paste, the mixing device is transferred to a low-speed mode of operation and a water-dispersive binder of 25-55 wt.%, A thickener of 0.3-1 wt.% Are introduced.

Water resistance is increased by increasing the barrier protection, which is provided by the thinnest mica plates, evenly distributed by gel-like phosphate binder nanoparticles.

Resistance to temperature extremes is ensured by high elasticity and non-shrinkage of mica plates.

Additional lightfastness is ensured due to the fact that the mica flakes have a mirror surface and the reflection coefficient prevails over the scattering coefficient.

Resistance to pollution is provided due to the fact that the paint film becomes smooth and water-repellent.

The mirror surface of the mica plates is ensured by the fact that the thickness of the mica plates is negligible, less than 1 μm, and due to this, the defects have a thickness less than the light wave.

The minimum thickness of the mica plates is achieved due to the fact that the bonds previously weakened by calcination between the flakes are not restored by grinding in the presence of an antistatic agent.

High dry residue is achieved through the method of introducing pigments. First, traditional pigments are dispersed. The paste is very thick at the beginning of the dispersion would not allow to introduce an additional amount of pigments. At the end of the dispersion, the paste liquefies, and the decorative mica introduced additionally does not require dispersion.

When mica is introduced into the grinding in an amount of <30 wt.%, Not only does the grinding time increase, but the desired dispersion of 5-100 microns is not achieved either.

When mica is introduced into the grinding in an amount of> 30 wt.%, The mixer will not mix the material.

When an antistatic agent is introduced into the mica grinding in an amount of <0.5 wt.%, The mica flakes will not have a thickness of less than 1 μm.

When an antistatic agent is introduced into the mica grinding in an amount of> 1 wt.%, Strong foaming will be observed and the mica flakes will not have a thickness of less than 1 μm.

Loading decorative mica together with all pigments for dispersion will not allow to obtain a high dry residue.

The inventive method is as follows. Mica waste is preliminarily calcined at a temperature of 700-800 ° C. Hot water is poured into a container equipped with a mixing device with a milling cutter and a dual speed switching mode at a rate of 69-70 wt.%, Then calcined mica is loaded in an amount of 30 wt.% And an antistatic agent of 0.5-1 wt.% Is introduced. The mixing device is transferred to a high-speed mode of operation and stirred for 7-8 hours. Then the mixer is transferred to a low-speed operation mode, the resulting material is diluted with water and filtration is carried out with washing. Next, prepare a colorful batch. Hot water is poured into the container 15-30 wt.%, With stirring at a low-speed mode of the mixing device, a gel phosphate binder is loaded, calculated on a dry residue of 0.5-4 wt.%, Weather-resistant pigments and fillers 20-40 wt.%, Antifoam 0.1-0.5 wt.%, Propylene glycol 1-2 wt.%. The mixer is transferred to high speed mode. Mixing is carried out until a pigment milling of 10 μm is obtained. Then load the paste of decorative mica in terms of a dry residue of 2-5 wt.%. After 20-30 minutes, after the mica is evenly distributed in the composition of the paste, the mixer is transferred to a low-speed mode of operation and a water-dispersive binder of 25-55 wt.%, A thickener of 0.3-1 wt.% Are introduced.

Example 1. In a container having a volume of at least 1 liter, with a mixing device and a cutting mill having a two-speed mode of operation, pour hot water 463 ml (69 wt.%), Turn on the mixing device for a low-speed mode of operation, pre-calcined mica waste is loaded in an amount of 200 g (30 wt.%), 7 g of antistatic agent (1 wt.%) are introduced. The mixing device is brought to a high-speed mode of operation and mixing is carried out for 7-8 hours. The mixing device is brought to a low-speed mode of operation and water is added to the tank to 1 liter. The contents of the glass are poured onto a vacuum filter, filtered, poured 3 more times with water and filtered again. The filtrate is removed and the mica paste is collected from the filter. Hot water of 1700 ml (17 wt.%) Is poured into a container with a volume of at least 10 l, 400 g (4 wt.%) Are loaded, calculated on a dry residue of 1.2 wt.% Phosphate gel binder. The mixing device is turned on to a low-speed mode of operation and mixed thoroughly, then 1900 g (19 wt.%) Of titanium dioxide, 970 g (9.7 wt.%) Of filler - Procal aluminum oxide are loaded, 30 g (0.3 wt. %) defoamer type BYK-036, which is an emulsion of hydrophobic components and mineral oil based on paraffin containing silicone, 100 g (1 wt.%) propylene glycol, and the mixing device is switched to a high-speed mode of operation. After 7-8 hours, paste decorative mica paste 260 g (2.6 wt.%) In terms of dry residue of 2 wt.%. After 20-30 minutes, the mixing device is transferred to a low-speed mode of operation and 4600 g (46 wt.%) Of the SKS-65 GP-B latex binder and 40 g (0.4 wt.%) Of the Akrisol TT-935 thickener are introduced representing a milky white dispersion of an acrylic polymer. Stir until a homogeneous mass and pack. The resulting paint gives a shiny, smooth film, resistant to moisture and pollution, has the following technical characteristics:

Spreading rate, g / m ² 90 % of critical volumetric filling 55 Mass fraction of nonvolatile substances,% 55

Example 2. In a container having a volume of at least 1.5 liters, with a mixing device and a cutting mill having a two-speed mode of operation, 814 ml (69.5 wt.%) Of hot water is poured, the mixing device is turned on for a low-speed mode of operation, loaded pre-calcined mica 350 g (30 wt.%), injected 6 g of antistatic agent (0.5 wt.%). The mixing device is brought to a high-speed mode of operation and mixing is carried out for 7-8 hours. The mixing device is brought to a low-speed mode of operation and water is added to the tank to 1.5 liters. The contents of the glass are poured onto a vacuum filter, filtered, poured 3 more times with water and filtered again. The filtrate is removed and the mica paste is collected from the filter. In a container having a volume of at least 10 l, pour hot water 2090 ml (20.9 wt.%), Load 300 g (3 wt.%) In terms of dry residue of 1 wt.% Phosphate gel binder. The mixing device is switched on to a low-speed mode of operation and mixed thoroughly, then 1660 g (16.6 wt.%) Of titanium dioxide are loaded, 1300 g (13 wt.%) Of the filler is micronized sphene, 30 g (0.3 wt.%) Of antifoam type BYK-036, which is an emulsion of hydrophobic components and paraffin-based mineral oil containing silicone, 100 g (1 wt.%) propylene glycol, and the mixing device is switched to a high-speed operation mode. After 7-8 hours, paste decorative mica paste 450 g (4.5 wt.%), Calculated on the dry residue of 3.5 wt.%. After 20-30 minutes, the mixing device is transferred to a low-speed mode of operation and 4030 g (40.3 wt.%) Of the latex binder type SKS-65 GP-B and 40 g (0.4 wt.%) Of the Akrisol TT- thickener are introduced 935 ", which is a milky white dispersion of an acrylic polymer. Stir until a homogeneous mass and pack. The resulting paint gives a silky film that is resistant to moisture and pollution, has the following technical characteristics:

Spreading rate, g / m ² one hundred % of critical volumetric filling 65 Mass fraction of nonvolatile substances,% 54

Example 3. In a container having a volume of at least 2 liters, with a mixing device and a cutting mill having a two-speed mode of operation, 1153 ml (69 wt.%) Of hot water is poured, the mixing device is switched on for a low-speed mode of operation, pre-calcined mica 500 is loaded g (30 wt.%), injected 17 g of an antistatic agent (1 wt.%). The mixing device is brought to a high-speed mode of operation and mixing is carried out for 7-8 hours. The mixing device is brought to a low-speed mode of operation and water is added to the tank to 2 liters. The contents of the glass are poured onto a vacuum filter, filtered, poured 3 more times with water and filtered again. The filtrate is removed and the mica paste is collected from the filter. Hot water of 2000 ml (20 wt.%) Is poured into a container with a volume of at least 10 l, 350 g (3.5 wt.%) Are charged, calculated on a dry residue of 1.1 wt.% Phosphate gel binder. The mixing device is turned on for low-speed operation and mixed thoroughly, then 1530 g (15.3 wt.%) Of titanium dioxide, 1470 g (14.7 wt.%) Of weather-resistant filler - Procal aluminum oxide, 30 g (0, 3 wt.%) Defoamer type BYK-036, which is an emulsion of hydrophobic components and paraffin-based mineral oil containing silicone, 100 g (1 wt.%) Propylene glycol, and the mixing device is switched to a high-speed mode of operation. After 7-8 hours, paste of decorative mica paste 660 g (6.6 wt.%), Calculated on the dry residue of 5 wt.%. After 20-30 minutes, the mixing device is transferred to a low-speed mode of operation and 3820 g (38.2 wt.%) Of the latex binder type SKS-65 GP-B and 40 g (0.4 wt.%) Of the Akrisol TT- thickener are introduced 935 ", which is a milky white dispersion of an acrylic polymer. Stir until a homogeneous mass and pack. The resulting paint gives a silky film that is resistant to moisture and pollution, has the following technical characteristics:

Spreading rate, g / m ² 110 % of critical volumetric filling 70 Mass fraction of nonvolatile substances,% 55

The above examples show that, despite the fact that% of the critical volumetric filling increases, the paint still has a silky sheen and high resistance to moisture and pollution. This is possible due to the ever-increasing percentage of thin mica with a mirror surface of flakes. Most highly dusty components: silicon dioxide, aluminum phosphates, micronized mica, are introduced into the paint in the form of a paste, making production as safe as possible. The paint film easily attaches to any temperature difference, stretches and returns to its size again, without forming not only large defects, but also microcracks.

Claims (1)

A method of preparing paint for a protective and decorative coating of building structures, including dispersion in water of weather-resistant pigments and fillers, antifoam, propylene glycol and a phosphate gel-like binder - the product of the interaction of a solution of phosphoric acid and nepheline concentrate, obtained by adding to a solution of phosphoric acid with a concentration of 20-30 % P ₂ O ₅ nepheline concentrate until a pH of 1.5 is reached or with a concentration of 11% P ₂ O ₅ , until a pH of 3.5 is reached, the mixture is left to stand for 0.5 h, after sedimentation of non-opened particles that are not soluble in water, subsequent heat treatment of the mixture at 80-100 ° C, cooling, washing, filtering on a vacuum filter to 50-70% humidity, removing the filtrate of water-soluble salts, obtaining a gel-like phosphate binder on the filter followed by the introduction of a decorative mica paste obtained by calcining mica waste, grinding by wet method at a high-speed mode of a mixing device equipped with a mill of 30 wt.% calcined mica waste in 6 9-70 wt.% Water, with the addition of an antistatic agent in an amount of 0.5-1 wt.%, Washing and filtering, then, under the low-speed mode of the mixing device, an inlet-dispersion binder and an acrylic thickener are introduced in the following ratio of components in the paint, wt.% : Water 15-30 Gel phosphate binder in terms of dry residue 0.5-4 Weatherproof pigments and fillers 20-40 Pasta decorative mica in terms of dry residue 2-10 Antifoam agent 0.1-0.5 Propylene glycol 1-2 Water Dispersion Binder 25-55 Acrylic Thickener 0.3-1