CS241437B1 - Dispersion plaster - Google Patents

Abstract

Dispersion plaster is intended for unifying the surfaces of building elements and for treating the surfaces of building objects during reconstructions and renovations. The binder of the plaster is an aqueous dispersion of a carboxylated copolymer and the rheological properties are adjusted by salts of polyacrylic acid or neutralized copolymers of ethyl acrylate-acrylic and/or methacrylic acid. Hydrophilic reactive groups of polymers ensure high cohesion of the plaster to the substrate and low diffusion resistance. The plaster can be applied by painting or spraying onto cleaned and repaired substrates. The reacted plaster has good coverage even in small thicknesses, easy workability, good adhesion to substrates, low diffusion resistance and a uniform structure with a uniform color shade. The material does not flow when applied in different thicknesses and exhibits good rheological properties.

Description

The invention relates to a dispersion plaster with high adhesion to substrates and low diffusion intended for performing unifying coatings or spraying of surfaces of building elements already provided with a base layer of plaster or surfaces of objects during renovations and reconstructions.

During reconstruction and renovation of surfaces, damaged areas are often repaired or parts of the surface treatment are removed. The repaired areas are different in color and sometimes do not even meet functional requirements. Aesthetic defects of new surfaces as well as the uneven appearance of repaired surfaces are removed with a new layer of plaster. This new plaster in most cases worsens the quality of the entire surface treatment, for example by increasing the diffusion resistance. It is also necessary to ensure good cohesion of the existing substrate with the new plaster, which has a significant weight, and to solve the joints of individual elements. Applying plaster in this way is not very productive and requires a significant amount of materials. The dispersion plasters known so far are not suitable for treating substrates due to their low cohesion with the substrate and high diffusion resistance. To increase stability, the rheological properties of these plasters are adjusted by adding fibers, most often asbestos fibers, which are hygienically objectionable.

These shortcomings are solved by a fine-grained, pigmented dispersion plaster with low consistency, high hiding power & good workability, which unifies the entire surface and covers any repairs and color irregularities. The binder of the plaster is an aqueous dispersion of a carboxylated copolymer, which, due to its hydrophilic nature, ensures high adhesion to the substrate and has a low diffusion coefficient. Rheological properties are provided by viscous liquids based on polyacrylic acid salts or neutralized ethyl acrylate-acrylic and/or methacrylic acid dispersions.

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The dispersion material is applied by painting or spraying on the prefabrication-made basic plaster that meets all functional requirements*. Overspraying the fine-grained material increases the aesthetic level of the facades, their color unification and uniformity. The same requirements apply to the reconstruction and renovation of older buildings. Functionally satisfactory surfaces are only cleaned, defective ones are removed and treated according to the nature of the original material. The unifying coating or spraying ensures the color unification and uniformity of the surface.

The dispersion plaster according to the invention contains mineral fillers with a grain size of max. 1.6 mm, preferably 0.5 mm in an amount of 25 to 55% by weight*, further pigments in an amount of 5 to 15% by weight, surfactants in an amount of 0.2 to 3.0% by weight, binders, in particular aqueous dispersions of carboxylated synthetic polymers with a dry matter of 50% by weight in an amount of 10 to 30% by weight, thickeners or thixotropic agents based on salts of polyacrylic acids or neutralized dispersions of ethyl acrylate-acrylic and/or methacrylic acid in an amount of 0.2 to 4.0% by weight, dispersants in an amount of 0.2 to 5.0% by weight*, fungicides in an amount of 0.01 to 0.50% by weight, water in an amount of 15 to 40% by weight. and optionally antifoams in an amount of 0.01 to 1.00% by weight.

For illustration, we present the composition of the material suitable for coatings

micronized limestone (up to 0.5 mm) 44 parts of matter colloidal SiOg 1.3 pigment 8.0 Sodium hexametaphosphate (10% solution) 2.0 sodium lauryl sulfate 0.6 dispersion of carboxylated styrene^acrylo- 18 0 of copolymer polyacrylic acid sodium ammonium salt 1.0 defoamer 0.2 — ^M — fungicide 0.2 water 24.7 «»

After drying, the coating material forms a uniform and uniform surface in color with adhesion to the substrate above 0.8 MPa, with wet abrasion above 60 min., with diffusion below 1.5 m. The material resists weathering, freezing cycles and thermal changes. The material of the above composition can be used for spraying when diluted with 5 to 15 parts of water per 106 parts by weight of the coating material.

- 3,241,437

According to another example, a paint and spray dispersion plaster is prepared by homogenizing the following components;

ground quartz sand up to 0.2 mtn 42.0 parts of matter colloidal Si0 ₂ 3.5 M pigment 3.0 sodium tripolyphosphate (15% solution) 3.0 tt M «* carboxylated copolymer dispersion styrene-ethyl acrylate with a dry matter content of 5 0% by weight 20.1 — ^W w. neutralized ethyl acrylate copolymer 3 5 — methacrylic acid defoamer 0.1 fungicide 0.3 water 24.5

The dispersion plaster has adhesion to substrates higher than 1.0 MPa, wet abrasion 60 min., diffusion 0.3 m and water-2 »* tightness 0.2 lm. The material can be applied by painting or spraying and is particularly suitable for surface treatment during the reconstruction of monuments and historical buildings, for the rehabilitation and restoration of the building stock and for industrial buildings with wet operations.

Claims (3)

BACKGROUND OF THE INVENTION 241 437 1) Dispersion plaster composition containing mineral fillers with a grain size of up to 1.6 mm, preferably up to 0.5 mm in an amount of 25 to 55 parts, pigments in an amount of 5 to 15 parts, surfactants in an amount of 0.2 to 3.0 parts, polyphosphate-based dispersants in an amount of 0.2 to 5.0 parts, a fungicidal additive in an amount of 0.01 to 5.00 parts, and water in an amount of 15 to 40 parts, wherein the binder is an aqueous dispersion of a carboxylated synthetic copolymer % of dry matter 50% in amounts of 10 to 30 parts and theological properties are regulated by polyacrylic acid salts and / or neutralized ethyl acrylate-acrylic and / or methacrylic acid copolymers in amounts of 0.2 to 5.0 parts, all in parts by weight. 2. The dispersion plaster composition according to claim 1, characterized in that the aqueous dispersion of the carboxylated synthetic copolymer consists of copolymers of styrene, acrylic acid esters of acrylic acid and / or methacrylic acid, preferably styrene-2-ethylhexyl acrylate-acrylic acid or styrene-ethyl acrylate-acrylic acid. or styrene-butyl acrylate-acrylic acid or styrene-ethyl acrylate-methacrylic acid with a dry matter content of 35 to 55% by weight, preferably 50% by weight. 3. The dispersion plaster composition according to claim 1, wherein the acrylic thickener comprises an aqueous solution of sodium and / or sodium ammonium salts of an acrylic copolymer having a viscosity of 300 to 20,000 mPas, preferably 6500 + 3500 mPas, or if titralized. an ethyl acrylate-acrylic acid and / or methacrylic acid copolymer.