CS214296B1 - Method of treatment of surface micro-structure of building materials - Google Patents

Abstract

The invention entitled "Method for treating the surface microstructure of building materials" provides for a two-stage procedure for treating the surface layer of building materials with aqueous solutions of polyvinyl alcohol with suitable coagulant additives, or possibly with aqueous dispersions of macromolecular substances. The treatment strengthens the surface layers of the substrate, reduces its viscosity, permeability and creates a very thin layer with high diffusion resistance. The invention solves the problem of impermeability of building materials to water and water vapor and is applicable mainly in the construction and production of building materials sectors.

Description

The present invention relates to a process for the treatment of the surface microstructure of building materials by a two-stage technology in which a dilute polyvinyl alcohol solution with coagulants is applied to the surface to achieve semipermeability of the surface layer and surface reinforcement. and optionally aqueous dispersions of macromolecular substances.

The surface properties of building materials, especially concrete ones, exhibit generally low mechanical strengths and do not correspond to the cross-sectional characteristics of the entire structural depth. Therefore, the surfaces are treated in a variety of ways, which then serve as surface treatments. The mechanical treatment consists in abrading a surface layer of a few millimeters thickness. Abrasion removes a mechanically weak and inconsistent surface layer while aligning the surface. This method is demanding on grinding equipment, requires the extraction of grinding dust, and in the case of wet grinding, it is necessary to evacuate the resulting slurry. In addition, excess moisture is introduced into the structure. The surface non-cohesive layers are also removed chemically by means of acid solutions, followed by neutralization of the excess acid and washing of the resulting soluble salts. The method requires safety and hygiene measures and the necessary technological breaks.

According to other methods, the surface of building materials is treated with dilute solutions or aqueous dispersions of polymers. This so-called. penetration, impregnation or impregnation often fails to achieve the desired effect because the polymeric surface acts as a filter layer. Diluents or solvents enter the depth of construction and the polymer film remains only on the surface. This film is a frequent cause of malfunctions due to its low and durability. Defects are manifested in particular by tearing off the surface layer with the surface layer of the substrate.

The surface treatment is therefore often carried out by depositing layers of treated inorganic or organic compositions which simultaneously serve as protective and decorative finishes. Reactive resins (epoxy, polyurethane, unsaturated polyester resins, acrylates, etc.), various foil materials and the like are used for this purpose. The disadvantage of these methods is the necessary surface treatment, dry substrate and sufficient mechanical strength of the surface layers. Often, mineral binder layers are used, in particular cement or anhydrite (NSC Pat, 23 59 290, Crayfish Pat. 263 607, NSC Pat. 22 12 843, V. Brit. Pat.

889,172, US Pat. 4,053,323 atá ·). The above-mentioned spoons require considerable thick coatings applied by several methods to ensure the weight and thickness of the layer to provide ease and moisture permeability to moisture, water and steam. The methods are very laborious, low productivity and require large technological breaks.

According to the present invention, the method of treating the surface microstructure of building materials by a two-stage technology is carried out by applying an aqueous solution of polyvinyl alcohol having a dry weight of 0.4 to 16.4% by weight containing 1.5 to 50% by weight. with respect to polyvinyl alcohol, a coagulating agent, with a subsequent coating of a cement impermeable composition comprising cement, fillers, modifying agents, water and 0.05 to 0.5%.

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8.5 wt. % polyvinyl alcohol, 0.003 to 2.5 wt. % of a coagulant and 0.2 to 6.0 wt. surfactants having a hydrophilic-lipophilic balance (H1B) of 8 to 16, all based on the cement content.

The method of treating the surface micro-structure of building materials according to the invention requires a two-step, highly productive method. The first procedure is to impregnate the surface with treated aqueous solutions of polyvinyl alcohol with coagulants. This treatment strengthens the surface layers of the substrates, decreases its absorbency and permeability and creates a very thin layer with high diffusion resistance. At the same time, this intermediate layer increases the adhesion properties of the substrate with further layers. Actually an effective layer consisting of a cementitious composition and containing fillers, modifiers, water and synergistically based additives based on polyvinyl alcohol, coagulants and surfactants, or water dispersions of polymers, increases the compatibility of the additives with the cement, sp8s impermeability to water and solvent resistance. water.

The surface treatment according to the invention reacts in short periods of time, requires at least technological breaks and substantially increases the mechanical strength of the structure. Particularly noticeable is an increase in tensile and flexural strength, a decrease in the modulus of elasticity and an increase in abrasion and abrasion resistance. The layers produced according to the invention have high toughness, flexibility and are still bulk. They can be applied at any depth from 1.0 mm to multimeter thickness. The composition of the compositions of the invention is suitable for floor constructions, linings and linings of pipes, channels and wherever water and water vapor tightness is required. The material is suitable for sealing stoneware, grouting ceramic elements and the like. The advantage of the surface treatment method according to the invention is that it can be converted to wet substrates as well as to floors without waterproofing layers.

Example 1

Penetrating. solution prepared from 99 wt. % of polyvinyl alcohol having a degree of hydrolysis of 82% and a polymerization degree of 1200 and 1 wt. Substrate concrete is impregnated with a portion of a 10% aqueous solution of Al 2 SO 4. After 6 hours at 20 ° C, a 2 cm thick layer of 27 wt. parts of cement (PC 325), 54 wt. parts of sand with a grain size of 0.1 to 4.0 mm, 17.5 wt. parts of float chalk, 1.0 wt. parts of acidic pulp mill and 0.5 wt. parts of aluminum sulfate and from 18 wt. parts of water containing 0.4 wt. parts of polyvinyl alcohol. The mass is perfectly homogenized and poured onto the substrate. After setting it has a compressive strength of 35 MFa, a bending tensile strength

7.8 MPa, 8 m diffusion and absorbability below 0.1 wt. Mixture free of polyvinyl alcohol and aluminum sulphate my compressive strength 24 MPa, tensile strength is 3.1 MPa, diffusion

1.8 m and absorbability 5.3% wt.

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Example 2

A panning solution was prepared as in Example 1. A layer of 30 wt. diy etru ^ ppQrllapahdho P®4> ahŽM? 5 °), ⁸ 5 parts by weight · p limestone grit grain size 0.1 to 1.6 mm, 10 wt. parts of micronized limestone, 0.6 wt. parts of case, 0.4 h |><> £. parts of sodium sulfate and 1.0 hg / liter. % of sodium dimethylmethanediulfonate. The mixture is perfectly homogenized with 1 part by weight of water in which it is 2% by weight. part polyyri} ylalkphQlv |. Is y hpnitatXe layered? W on the surface of the concrete pipe. The compressive strength of the sealed layer was 23.2 MPa, and the bending strength at 5.5 MPa, the diffusion of 9.5 ip and the absorbent φ% by weight per 24 hog. 5 lf £, p $ vnpa ^ in the zi? It is 1.8 MPa, diffusion 2.4 m, and 2.5 mm mass per 24 h.

Example 3

The penetrant solution is prepared similar to that of Example 1. Prior to mixing and penetration, the penetration solution is diluted with water in a ratio of 1 part solution to 9 diplomas of water.

A layer of material prepared from 27 wt. parts of white cement (class 490,), 50 wt. parts of ground limestone with grain size up to 0,5 mm,

1.5 wt. % of aluminum sulfate, 3 wt. parts of color pigment and 0.5 wt. parts of carbonic acid diamide. Stirring and 12 rot. parts by weight of water which is Qbaefe, 2 wt. parts by weight of polyvinyl alcohol 14% by weight; and $, wt. parts of the water diaparesis. polymer. It is applied to the substrates by spraying and forms an impermeable layer with excellent mechanical properties and a high aesthetic level.

Claims (4)

SUBJECT MATTER Process for treating a surface microstructure of building materials by a two-stage process, characterized in that an aqueous solution of polyvinyl alcohol having a dry matter content of 0.4 to 16.4% by weight, containing 1.5 to 50% by weight, is applied to the surface of the building materials. with respect to the polyvinylalphphol coagulant, followed by a non-cementitious impermeable composition comprising cement, fillers, modifiers, water and 0.05 to 8.5 wt. % polyvinyl alcohol, 0.003 to 2.5 wt. a coagulant and 0.2 to 6.0% by weight of a hydrophilic-lipophilic balance (HIB) surfactant of 8 to 16, all based on the cement content. . '' 2. The method according to claim 1, wherein the polyvinyl alcohol coagulating agent comprises at least one of the water-soluble sulphates, chlorides, borates, carbonates and phosphates of metals I to III. groups, ammonium hydroxide, alpha-naphthol, carbonic acid diamide, resorcinol and sodium salicylamide. 3. Process according to claim 1, characterized in that the surfactants are compounds which simultaneously act as hardening and curing regulators of the cementitious binder, in particular mono-, di-, triethanolamine and / or mixtures thereof, further mono-, di-, triethylamine and / or a mixture thereof. 4. Process according to claim 1, characterized in that the aqueous solution of the vinyl alcohol poles contains simultaneously aqueous dispersions of macromolecular substances in an amount of 4.0 to 16.0% by weight. dry matter, based on cement binder.