CZ191691A3 - mineral siliceous hydrophobized coating compositions - Google Patents

Abstract

The coating compositions consist of potassium water glass, 8 to 20 % by weight of colloidal silicon dioxide, preferably 10 to 15 % by weight of SiO2 with a weight ratio of SiO2/K<2>O = 2.5 to 6, preferably 4 to 5, 0.1 to 3% by weight of an active hydrophobizing substance based on silanes and polyorganosiloxanes, alternatively with hardening accelerators, 20 to 30% by weight of calcium or magnesium carbonates or their mixtures, 10 to 20% by weight of aluminium, alkali metals, alkali earth, magnesium silicates and silicic oxide, up to 15% by weight of white and colour pigments, added according to the required intensity of the colour. The compositions are produced in the following manner: the inorganic additives and pigments and 0.1 to 3% by weight of the active hydrofobizing substance are added while mixing into 100 to 300 parts of potassium water glass at a concentration of 10 to 40% by weight, with a weight ratio of SiO2/K2O = 1.8 to 2.2. Before use, 100 to 300 parts of the colloidal solution of silicon dioxide, at a concentration of 10 to 30% by weight, is added while mixing into the coating composition. During production, the water glass can be replaced by colloidal silicon dioxide, and vice-versa, silicon dioxide with water glass. Two-component painting compositions are produced from the same constituents, only, before use, the mixture of water glass, colloidal silicon dioxide and active hydrofobizing substance is mixed with inorganic additives and pigments or with hardening accelerators to produce painting compositions with dry matter of about 50% by weight.

Description

The invention relates to a mineral silica hydrophobized coating composition based on potassium water glass, a colloidal oxide. Silica and mixtures thereof with inorganic additives, white or colored pigments and hydrophobic substances, optionally with the addition of accelerators, hardening.

BACKGROUND OF THE INVENTION

Inorganic siliceous coatings and sealants are known and are mainly used in refractory technology and for acid-resistant environments. Their binder properties are based on the condensation of the silica released from the water by the action of air carbon dioxide or by the addition of acidic solutions and compounds (hardening accelerators which form acid by hydrolysis) to form high molecular polycondensation products. These harden when hardened and form a solid coating with good adhesion with inorganic additives and pigments.

When used as an outdoor coating, waterglass silica paints are disadvantageous in that they are too hydrophilic, wettable and permeable to water with a low-strength paint with considerable abrasion.

Also, the mineral silica sealants, which are essentially two-component paints, are water-permeable and disintegrate after prolonged contact with water.

Therefore, it was an object of the invention to improve the strength of the coating, while at the same time reducing the water permeability to the coating, thereby increasing the weather resistance of the coatings. Further efforts were made to improve the thixotropic properties of the paint and its workability.

SUMMARY OF THE INVENTION

The essence of the mineral silica hydrophobized paints based on potassium water glass, colloidal silica and mixtures thereof with the addition of inorganic substances, white or colored pigments and hydrophobic substances, optionally with the curing accelerators according to the invention is that they contain diluted potassium water glass containing 4 to 10 %, preferably 5 to 6 wt. silica and a dilute colloidal silica solution containing 4 to 10 wt.%, preferably 5 to 6 wt. the silica ratio such that the weight ratio between silica and potassium oxide is 2.5 to 6, preferably 4 to 5 and 0.1 to 3% by weight, preferably 0.5 to 1% by weight. an active hydrophobizing substance consisting of polyorganosiloxane compounds such as water-soluble alkali salts of dimethyl, diphenyl, methyl α-phenylsilanolate, or water-insoluble elastomers of polydimethylsiloxane in the form of an aqueous emulsion, 20 to 30 wt. limestone, dolomite, magnesite or mixtures thereof, 10 to 20 wt. aluminum silicates, aluminum silicates of alkali metals, alkaline earths and magnesium, white or colored pigments, added according to color intensity.

It was unexpectedly found out that the diffusion and strength of the coating film as well as the thixotropic properties of the coating material increase with the addition of colloidal silica to the water glass. By using polyorganosiloxanes as the active hydrophobizing substance, it is possible to hydrophobize mineral silica coatings to some degree, thereby reducing the wettability and water permeability of the coating film without compromising the adhesive and technological properties of the coating.

Polyorganosiloxanes, in particular polyetersiloxanes, are preferably used as siloxanes. They are block copolymers which are formed from a linear or branched polysiloxone block, for example polydimethylsiloxane and at least one polyether or other polar block, such as acrylic or methacrylic derivatives. By combining non-polar hydrophobic polydimethylsiloxone segments with polar acrylic, methacrylic or polyether, in particular polyethylene oxide units, as side chains, copolymers are available, the properties of which prove to be particularly advantageous for the mineral silica color treatment according to the invention.

These active hydrophobizing substances are known and used to improve the organophilic properties of both inorganic and organic pigments of polar character. They have not been applied to mineral water-based silicate inks and colloidal silica.

- 3 The added mineral additives are used as colorless, ground or floated clay aluminum silicates, alkali metal aluminum silicates and magnesium silicates as possible, such as kaolin, bentonite clays, talc and mica. Other fillers are limestone, dolomite, magnesia, or mixtures thereof, which improve the opacity and processability of the paint. Aluminum silicates serve not only as a filler, but also as a component improving the thixotropic properties of the paint, especially bentonite clays. Talc and mica reduce the water absorption of the coating and at the same time improve its strength, smoothness and abrasion.

The binder consisting of potassium water glass and colloidal silica has a lower amount of potassium oxide and a higher amount of silica than water glass alone. This improves the quality of the coating film. In water glass, the SiO 2 / O 2 weight ratio is in the range of about 1.8 to 2.2. By adding colloidal silica, it is possible to increase the weight ratio up to 6 or more as desired, preferably to 4 to 5. On account of the wettability and water permeability of the coating film, the addition of an active hydrophobising substance in the coating composition of 0.1 to 3 phy. The coating composition can be produced up to 70% by weight. dry matter, preferably in a pasty, well-mixed form.

For two-component paints where the paint is required to cure for a short period of time, curing of the paint can be accelerated with the aid of curing accelerators. They are the latest condensed insoluble aluminum phosphates. Aluminum triphosphate AIH2P5O1Q.2Η £ is used for rapid curing, aluminum metaphosphate - B is preferred for slow curing. The homogenized powder mixture is mixed with a dilute waterglass and a colloidal silica solution with the addition of a hydrophobic substance and a non-ionic surfactant to a dry substance of about 40 to 50 phy weight.

The essence of the process for preparing the mineral silica coating compositions according to the invention is that up to 100 to 100 g of dilute potassium water glass having a concentration of 10 to 40 phy by weight or 100 to 300 g of an aqueous solution of colloidal silica of 10 to 40 phy by weight. . with stirring and at normal temperature, inorganic additives consisting of 15 to 30 ph. limestone, dolomite, magnesite or mixtures thereof, from 10 to 20 wt. aluminum aluminates, alkali aluminum silicates, soils

- 4 and magnesium. Depending on the color intensity, white or colored pigments and 0.1 to 37% by weight, preferably 0.5 to 70% by weight, are added. active hydrophobizing substance. A coating composition is obtained in paste form with approximately 60 wt. dry matter. Before use, the coating composition prepared with waterglass is diluted and mixed with a solution of 200-400 g of colloidal silica at a concentration of 10 to 10% by weight, while the coating composition prepared with colloidal silica is diluted and mixed with 200-400 g of dilute potassium water glass having a concentration of 10 to 30% by weight such that the weight ratio 8102 /? 2? is 2.5 to 6, preferably 4 to 5, and the total amount of bound and colloidal silica is 80 to 200 g, preferably 100 to 150 g in 100 g of paint having a dry weight of 40 to 50 wt.

The mixing of colloidal silica and waterglass results in a gradual gelation of the silica, which improves the thixotropic properties of the paint, while at the same time deteriorating its shelf life,

For this reason, waterglass and colloidal silicon dioxide in the coating compositions are mixed before use.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

To 300 g of potassium water glass of module 2.1, density 1.35 containing 75 g of SiO2, 260 g of demineralized water and 3 g of bentonite are added under stirring and at normal temperature. After a 15 minute delay, 160 g of limestone, 55 g of talc, 47 g of kaolin and 75 g of anatase white are added.

A white paint of 45 ° C was obtained. dry matter. The paint film has a diffusion of 0.22 m, a water permeability of 4.8 l / m ² and a wear time of 35 minutes.

Example 2

273.2 g of demineralized water and 3 g of bentonite are added with stirring to 200 g of potassium water glass of module 2.1, density 1.35, containing 50 g of SiO2. After a 15 minute delay, 218 g of limestone, 103 g of talc, 30 g of mica, 113 g of anatase white, 5 g of LUKOPOB-39, a product of the Cologne Factory / aqueous potassium salt of methyl and phenylsilanolate, 2 g of non-ionic wetting agent SLOVÁZOL-352O R.

A white coating composition is obtained in a paste-like form with 60% by weight.

dry matter,

- 5 which is diluted and mixed with 500 g of 20% by weight before use. flow rate of T03IL colloidal silica from TONaCO Nestemice containing 60 g ^per 48.3 phy. dry matter. The paint film has a diffusion of 0.16 m, a water permeability of 1.8 l / m ² and a wear of 55 minutes.

Example 3

The procedure of Example 2, except that 200 g of 30 wt. a colloidal silica solution and instead of 30 g anatase white 30 g ultramarine.

Light blue paint is obtained. dry matter, which is diluted with glass containing 50 g SiOg. The paint film has a diffusion of 0.1 lm, 54 minutes »the paste-like mass with oO 7 ° is mixed with 300 g of potassium water-permeability 1.9 l / m, abrasion

Example 4

The process of Example 3, except that the coating composition was in a paste form with 60 phy. The solids are diluted and mixed with 300 g of colloidal silica containing 60 g of SiO2.

A light blue coating composition of 48% by weight is obtained. dry matter. The coating film has a diffusion of 0.12 m, a water permeability of 1.4 l / m, an abrasion of 70 minutes.

Example 5

The homogenized powder mixture consisting of 170 g of limestone, 60 g of talc, 50 g of mica, 80.5 g of anatase white, 3 g of bentonite is mixed before use with a mixed solution of 230 g of water, 200 g of diluted waterglass in module 2.1 containing Si0 ₂ 50 g and 200 g of colloidal silica solution containing 60 g Si0 _2, starting with 3 g of a nonionic surfactant SL07AZ0L R-3520 and 5 g of silicone emulsion 1UK0PREN E-7620, a product of Chemical Factory Cologne / elastomer based on polydimethylsiloxane /.

A white paint with a dry weight of 50% by weight is obtained. The coating film has a diffusion of 0.15 m, a water permeability of 1.9 l / m ² , an abrasion of 52 minutes.

Example 6

Example 5 except that 18 g of aluminum metaphosphate hardener - B form and 10 g of red ferric pigment Pepper TD-202 are added instead of 28 g of anatase white.

A light red coating composition of 50-7 wt. dry matter,

- 6 which hardens after 5 hours. The coating film has a diffusion of 0.15 m, a water permeability of 1.3 l / m, an abrasion of 65 minutes.

The paints were evaluated according to C3N 752560, 752573 and 752532.

Based on the performed tests, it was proved that the addition of colloidal silica and an active hydrophobising substance improved the diffusion and especially the water permeability of the coating film and

Industrial applicability

Mineral silica hydrophobized paints are mostly used for exterior coatings on facades, with lime-cement plaster for residential, exhibition, historic houses and industrial buildings. They are particularly suitable where the masonry is exposed to harsh weather conditions in mountain areas. They are also very useful for interior coatings exposed to high humidity and acidic environment in chemical and other industries. They can also be used in kitchens, bathrooms, healthcare, replacing expensive ceramic tiles and special coatings.

Claims (4)

1. Mineral silica hydrophobic coatings ns. potassium waterglass, colloidal silica base and mixtures thereof with inorganic additives with white or colored pigments, optionally with hardening accelerators, characterized in that they contain dilute potassium waterglass containing 4 to 10% by weight, preferably 5 to 6> □% by weight of oxide and a dilute colloidal silica solution containing 4 to 10% by weight of silica such that the weight ratio between silica and potassium oxide is 2.5 to 6, preferably 4 to 5 and 0.1 to 9, preferably 0.5 to 1% by weight of the active hydrophobizing substance, consisting of polyorganosiloxane compounds such as water-soluble alkali salts of dimethyl, diphenyl, methyl and phenylsilanolate, or water-insoluble elastomers of polydimethylsiloxane in the form of an aqueous emulsion, 20 to 30% by weight of limestone, dolomite, magnesite or mixtures thereof, 10 to ^20c ; ° by weight of aluminum silicates, alkali metal, alkaline earth and magnesium aluminum silicates, white or colored pigments, added according to color intensity. 2. A process for the production of a mineral silica hydropholized coating composition as claimed in claim 1, wherein inorganic additive consisting of 20 to 10% by weight of 10 to 40% by weight of diluted potassium water glass is added to 100 to 100 g of diluted potassium waterglass. % by weight of limestone, dolomite, magnesite or a mixture thereof, 10 to 20% by weight of aluminum silicates, aluminum alkali metal silicates, alkaline earths and magnesium, 0.1 to 1% by weight, preferably 0.5 to 1% by weight active hydrophobizing substance, white or color pigments added to the intensity of the hue, before use, the coating composition is diluted and mixed with 200 to 400 grams colloidal silica solution at a concentration of 10 to JO ^c / o by weight to the total amount of bound and colloidal silica equal to 80 to 200 g, preferably 100 to 150 g in 1000 g of coatings the mass of dry matter of about 40-50% by weight. J. A method for producing mineral silica coating compositions according to - 3. The method according to claim 1, wherein the same amount of colloidal silica is used to prepare the coating tip of the potassium water glass, and before use, the coating composition is diluted and mixed with the same amount of potassium water glass of the same concentration. 4. A process for the production of mineral silica hydrophobized paints according to claim 1, characterized in that the homogenized mixture of 350 to 400 g of inorganic additives, white and colored pigments, optionally with the addition of hardeners, is mixed with a mixed solution of 100 to 200 g. 30 parts by weight of potassium water glass and 100 to 200 g lOaž 30% solution of colloidal silica, 0.1 to 3 L by weight, preferably 0.5 to 1% by weight of hydrophobicizing active substance, from 0.1 to 0.5 ^and 7 weight nonionic wetting agents such that 1000 g of dry weight coating of about 40 to 50% by weight contains 80 to 200 g, preferably 100 to 150 g of bound and colloidal silica.