MXPA96004936A

MXPA96004936A - Composite silic

Info

Publication number: MXPA96004936A
Application number: MXPA/A/1996/004936A
Authority: MX
Inventors: Drechsler Andreas; Neupert Daniel; Newham Simon; Rademacher Ingo
Original assignee: Braas Gmbh 61440 Oberursel De
Priority date: 1994-04-22
Filing date: 1996-10-18
Publication date: 1998-02-01

Abstract

The present invention relates to: The invention relates to a silicate compound having at least one amorphous binder matrix containing alkali metal oxide and silicon dioxide and also containing oxides from the group consisting of aluminum oxide, calcium, titanium, magnesium, zirconium and / boric oxide. In order to provide a silicate compound which is suitable both for making a molding and a coating on a substrate, which resists the effects as well as the weather, especially alternating cycles of freezing and thawing and attack by acids, bleaches or contamination, it is proposed that the binder matrix amorphous contains 4 to 25 moles of silicon dioxide, formaldehyde, alkali metal oxide, alkali metal oxide, alkali metal oxide is the group consisting of lithium, sodium and / or potassium oxide and the amorphous binder matrix also contains up to 80 moles of aluminum oxide and / or up to 45 moles of calcium oxide, titanium, magnesium, zirconium and / or boric oxide evenly distributed per 100 moles of silicon dioxide

Description

COMPOSITE SILICATE D E S C R I P C I O N The invention relates to a silicate compound having at least one amorphous binder matrix containing alkaline oxide and silicon dioxide and also containing oxides from the group of aluminum oxide, calcium oxide, titanium dioxide, magnesium oxide, dioxide zirconium and / or boric oxide. A silicon compound of that nature can be used to coat building elements, in particular roofing tiles. The surface of roof tiles made of concrete, that is to say tiles for roofs made of concrete, is covered to avoid efluorescence and achieve an aesthetic appearance. Over time the coating of a roof tile is exposed to severe corrosion of the elements. While in summer under strong solar radiation the surface temperature can rise to approximately 80 °, in winter under freezing conditions it can drop to -30 °. Of critical importance is corrosion in freeze-thaw cycles and acid rain.

Ceiling tiles are usually protected with a plastic dispersion paint coating. The drawback of these plastic coatings is that the coating does not have a long term resistance in particular to ultraviolet radiation and therefore disintegrates after a few years. DE-25 39 718 B2 discloses a method for coating preformed construction components based on inorganic binders containing coaned aggregates with silicate-containing covers in glazed and / or phosphate form, whereby a plastic mixture is produced at From the inorganic binder and water and common aggregates, this mixture is configured in construction components on which a thin layer of an aqueous paste containing water crystal and / or metal phosphates and oxides and possibly pigments and fillers is applied, the which layer is then cured, whereby inorganic salts soluble in a minimum amount of 0.5% by weight in relation to the inorganic binder, or in the case of sand-lime bricks related to the binder plus the aggregates, are added in the mixture, which salts transform the aqueous paste, which is applied to the preformed building component at a rate of 190 to 400 g per m, in a n non-flowable state in gel form, whereby the preformed construction component is cured as the coating. For the purpose of coating, aqueous alkaline pastes with 42 to 63 mole% of silicon dioxide, 11 to 27 mole% of alkaline oxide and between 19 and 42 mole% of metal oxide, in relation to the total weight of these constituents. Metal oxides are added to the paste ZnO, MgO, PbO, CaO, BJOJ / or AljO-, for example. Alternatively combining the upper and lower limits result only in the artimetic form a molar ratio of silicon dioxide to alkaline oxide of between 1.56 and 3.82. However, the description and the embodiments only mention the use of water glass from 37 ° to 40 * Be, wherein the molar ratio of silicon dioxide to alkaline oxide is a maximum of 3.52. In order to transform said pulp into a non-flowable state in the form of a gel it is necessary to add soluble inorganic salts, which addition is the main characteristic included in the main clause of the patent DE-25 39 718 B2. According to the method described here, the paste is applied to the preformed building component and, together with the latter, it is cured either in the autoclave under pressure at high temperatures or in a thermal-only treatment at normal pressure. From the patent EP 0247910 an inorganic silicate coating is known, in which the binder matrix contains approximately 100 parts by weight of potassium silicate, approximately 10 to 40 parts by weight of fine particles of silicon dioxide in relation to the solids. and about 15 to 100 parts by weight of pearlescent pigment. When using glass of water with a molar ratio gives silicon dioxide to alkaline oxide of 3.95, the molar ratio of silicon dioxide to alkaline oxide in the coating can be up to 6.15. As a method for the production of a coated object, EP 0 247 910 Bl states that the coating compound is applied to the substrate and then, for curing purposes, it should be heated with this substrate at a temperature of about 200 ° C to about 400 ° C. The pearlescent pigment is contained in the coating in the form of particles that are surrounded by the binder matrix. No indication is found in EP 0 247 910 in relation to the addition of "additional oxidic constituents.

THE IHVEHCIOM The purpose of this invention is to create a shaped body as well as a silicate compound without organic substances, which forms a coating of a substrate, which composed of silicate is resistant to weathering, in particular to cycles of freezing-thawing and to attack by acids, lyes or herbs development. It will be possible to apply the coating to a substrate by simple methods, for example brushing, roller coating, pouring or spraying and curing it at a temperature of less than 200 ° C, preferably less than 100 ° C. The problem is solved by the invention in that the amorphous binder matrix contains from 4 to 25 moles of silicon dioxide per mole of alkaline oxide, that the alkaline oxide "consists of lithium, sodium and / or potassium oxide and that the binder matrix amorphous also contains homogeneously distributed per 100 moles of silicon dioxide, up to 80 moles of aluminum oxide and / or up to 45 moles of calcium oxide, titanium dioxide, magnesium oxide, zirconium dioxide and / or boric oxide. alkaline oxides or other oxides are mentioned here, these correspond to the designation of metal contents as oxides, which is usual in silicate analysis, even if these are actually present in the form of chemical compounds such as silicates, aluminates or similar compounds The binder matrix contains a very high proportion of silicon dioxide, namely 4 to 25 moles of silicon dioxide per mole of alkaline oxide. The silicate composition according to the invention is highly resistant to corrosion mentioned in the definition problem which can still be applied in the form of an aqueous silicate suspension to a roof tile. The silicate suspension hardens on the roof tile at a temperature of less than 100 ° C in a solid silicate compound which forms a coating This is important in particular for use on a concrete roof tile, when the hardening may also proceed at room temperature. The content of up to 80 moles of aluminum oxide per 100 moles of silicon dioxide causes the silicate compound to acquire a particularly high chemical resistance. Contents of up to 45 moles of calcium oxide, titanium dioxide, magnesium oxide, zirconium oxide and / or boric oxide per 100 moles of silicon dioxide also increase the strength of the silicate compound. The addition of the above substances increases both the hydrolytic resistance of the silicate compound and also its resistance to alkali corrosion, in particular acid corrosion, for example acid rain. Aluminum and calcium are particularly effective. It is advantageous to produce the silicate compound from an alkaline silica sol with a solids content of 30 to 70% by weight. The alkaline silica sol will have an average particle size of less than 130 nm. The production of the silicate compound from the alkaline silica sol with this particle size offers the particular advantage that a highly homogeneous binder matrix is obtained from the silicon dioxide and alkaline sources. In this way it is possible to achieve a structure corresponding to that of the glass in the binder matrix of the hardened silicate compound. Therefore, a glazed silicate compound can be produced at temperatures less than 100 ° C. • Due to the low temperature during production, it is possible to produce large shaped bodies that have a high dimensional stability and are free from temperature stresses. A silicate compound is obtained particularly without fractures with a smooth surface if the binder matrix contains a crystalline filler of the layer silicates class. The filler may consist, for example, of mica or also of a mixture of different layer silicates. A particularly smooth and lustrous surface of the silicate compound is obtained if the binder matrix contains a crystalline filler of the calcite category. The silicate compound may also contain slag sand and / or cement. Glazed blast furnace slag is designated as slag sand. During production, slag sand or cement, after incorporation into the aqueous solution, is at least attacked on the surface if not completely dissolved so that its constituents are distributed homogeneously in the binder matrix. The silicate compound can also contain glass powder with a calcium oxide content of at least 30% by weight, a silicon dioxide content of less than 70% by weight and an aluminum oxide content of less than 20% by weight . Like slag sand or cement, the glass powder is dissolved after incorporation into the aqueous solution. The silicate compound may contain coloring pigments to adjust it to a desired color. The silicate compound can be used as a weather protector if it is applied as a coating on a substrate. The substrate can be, for example, a roof tile. The thickness of the silicate compound applied as a coating can be on average between 0.02 and 2 mm. preferably about 0.1 mm. The silicate suspension for coating a roof tile can be produced on the basis of an aqueous solution of alkali silicate with a molar ratio of silicon dioxide / alkaline oxide less than 2 if the silicate solution is mixed, for example with silica sol or with another of the aforementioned substances with a high content of silicon oxide, in order to increase the proportion of silicon dioxide. Preference is given to a silicate solution containing potassium, but a solution containing lithium or sodium or a mixture of these can also be used. If the content of silicon dioxide is increased by adding silica sol, a chemically very pure silicate compound results after hardening. You can get an excellent compound He silicate valuable using fly ash. Obviously a solution of a pure alkali silicate or mixtures thereof can also be used, or silicic acid or substances with a high content of silicon dioxide can be dissolved in caustic potash or caustic soda. To coat a substrate, the silicate suspension can be applied with a brush, a roller, or preferably sprayed. During subsequent drying the aqueous silicate suspension hardens into a silicate compound that forms the coating. Fresh or cured concrete, metal or a mineral body are examples of substrate. Even porous surfaces are sealed with a closed film. The silicate compound according to the invention is excellently suitable for granules, sands or coating fillers. The silicate suspension is practically suitable for all applications where bonded cement binders are present, for example for joints with grouts or bonded construction materials. In addition, the silicate suspension can be used for decorative or ornamental propÃ²ßß. Differently colored silicate suspensions can be used to achieve a marble effect on the silicate compound. The production of silicate compounds according to the invention with variant compositions and their application is described in the following, using twelve exemplary embodiments.

EXAMPLE DB REALIZATION 1 600 g of a potassium silicate solution with a solids content of 45% by weight and a molar ratio of silicon dioxide / alkaline oxide was added in 3 minutes by stirring to 1440 g of an alkaline silica sol. aqueous with a solids content of 30% and an average particle size of 40 nm. After the addition of a potassium silicate solution the mixture was dispersed for 5 minutes, the molar ratio of silicon dioxide / alkaline oxide was then 5.8. Then the preparation was stored for 4 days in a sealed polyethylene container at room temperature; 756 g of mica with an average particle size of 36 μm together with 206 g of an aqueous pigment suspension with 61.5% by weight of an iron oxide pigment with an average particle size of 0.1 μm were then added and the mixture it was dispersed for 5 minutes at 1000 rpm. Then the aqueous silicate suspension was sprayed onto the exposed surface of a freshly cured concrete roof tile and dried at room temperature for 1 hour. The concrete roof tile had a matte red coating with an average thickness of 0.1 m.

EXAMPLE DB REALIZATION 2 80 g of pure potassium metaborate was added to 400 g of an alkaline potassium silicate solution with a solids content of 45% by weight and a molar ratio of silicon dioxide / alkaline oxide of 1.3; this suspension was heated to 80 ° C until a clear solution developed and then cooled to room temperature. The cooled solution was stirred in 1400 g of an aqueous alkaline silica sol with a solids content of 30% by weight and an average particle size of 40 nm. The molar ratio of silicon dioxide / alkaline oxide was then 5.9. The entire preparation was dispersed and then 40 g of amorphous aluminum oxide with an average particle size of less than 13 nm was added. The aluminum oxide content was 4.7 moles per 100 moles of silicon dioxide. Then the mixture was dispersed and stored for a day in a sealed polyethylene container at room temperature; 624 g of mica with an average particle size of 36 μm together with 93.6 g of an aqueous pigment suspension with 61.5% by weight of an iron oxide pigment with an average particle size of 0.1 μa were then added. After dispersing the silicate solution it was then applied with a paint brush to the exposed surface of a cured concrete roof tile and dried at room temperature for 24 hours. The coated concrete roof tile was then heated for 2 hours at 120 ° C. The concrete roof tile had a matt red coating with an average thickness of 0.1 mm.

EXAMPLE DB EMBODIMENT 3 150 g of an alkaline solution of potassium silicate with a solids content of 45% by weight and a molar ratio of silicon dioxide / alkaline oxide were placed in a metal beaker. 330 g of fly ash from the melting chamber with a high amorphous proportion was stirred and this suspension dispersed for a short time. The fly ash of the melting chamber had the following constituents by weight calculated as oxides: 46% silicon dioxide, 30% aluminum oxide, 5.3% calcium oxide, 3.5% magnesium oxide, 5.0% potassium oxide and sodium 1.0%. After dispersion, 50 g of amorphous aluminum oxide with an average particle size of 13 nm and 45 g of iron oxide pigment with an average particle size of 0.1 μa were stirred. After intensive stirring in order to homogenize, 60 g of water was added. The molar ratio of silicon dioxide / alkaline oxide was now 4.9 and the aluminum oxide content of 49 moles per 100 moles of silicon dioxide. The proportion of the additional calcium and magnesium oxides was 20 moles per 100 moles of silicon dioxide. The resulting silicate suspension was immediately sprayed onto the exposed surface of a freshly cured concrete roof tile and dried for one hour at room temperature. The concrete roof tile had a matte red coating with an average dimension of o.l mm.

EXAMPLE OF EMBODIMENT 4 5 g of hydrated sodium tetraborate 10 (pa) was stirred in 100 g of an alkaline solution of potassium silicate at 80 ° C with a solids content of 45% by weight and a molar ratio of silicon dioxide / alkaline oxide of 1.3. Stirring was continued until a clear solution developed. After cooling to room temperature, the solution was stirred in 180 g of an aqueous alkaline silica sol with a solids content of 30% by weight and an average particle size of 40 μm. Then the mixture was stirred for 5 minutes. The molar ratio of silicon dioxide / alkaline oxide was now 4.4 and the boron oxide content was 2 moles per 100 moles of silicon dioxide. After storing for 4 days in a sealed polyethylene container at room temperature the silicate slurry was applied with a brush to the exposed surface of a cured concrete roof tile and dried for 1 hour at room temperature. The concrete roof tile had a colorless, transparent, slightly glossy coating with an average thickness of 0.1 m.

EXAMPLE DB EMBODIMENT 20 g of pure potassium metaborate was added to 100 g of an aqueous potassium silicate solution with a solids content of 45% by weight and a molar ratio of silicon dioxide / potassium oxide of 1.3; this suspension was heated to 80 ° C until a clear solution developed. After cooling to room temperature, the solution was stirred in 740 g of an aqueous alkaline silica sol with an average particle size of 40 nm. and a solids content of 30% by weight. Stirring was continued for 5 minutes and then the preparation was stored for one day in a sealed polyethylene container at room temperature. The aolar ratio of silicon dioxide / alkaline oxide was then 11.5 and the boric oxide content of 2 moles per 100 moles of silicon dioxide. 233 g of mica with an average particle size of 36 μm together with 43 g of an aqueous pigment suspension with 61.5% by weight of an iron oxide pigment with an average particle size of 0.1 μm were then added. This mixture was then dispersed for 5 minutes. Then the suspension of the prepared silicate was applied with a paint brush to the exposed surface of a pre-cured concrete roof tile. The drying was carried out for one day at room temperature and then for one hour at 190 ° C. The concrete roof tile had a matt red coating with an average thickness of 0.1 mm.

EXAMPLE OF EMBODIMENT 6 100 g of pure potassium metaborate was added to 200 g of a 5.6 molar caustic soda lye. Then the suspension was heated to 80 ° C with stirring until a clear solution developed. After cooling to room temperature, the solution was stirred in 827 g of silica sol with a solids content of 30% by weight and an average particle size of 40 nm. The resulting mixture was dispersed for 5 minutes and then stored for one day in a polyethylene container at room temperature. The molar ratio of silicon dioxide / alkaline oxide was 4.2. The boric oxide ratio was 11 moles per 100 moles of silicon dioxide. 413 g of mica with an average particle size of 36 μm and 105 g of an aqueous pigment suspension with a content of 61.5% by weight of iron oxide pigment of an average particle size of 0.1 μm were then stirred in the dissolution vessel. This mixture was then dispersed for 5 minutes. The prepared silicate slurry was applied with a paint brush on the exposed side of a pre-cured concrete roof tile and dried for * one hour at room temperature. The concrete roof tile had a matt red coating with an average thickness of 0.1 mm.

EXAMPLE OF EMBODIMENT 7 150 g of an alkaline solution of potassium silicate with a solids content of 45% by weight and a molar ratio of silicon dioxide / alkaline oxide of 1.3 was placed in a metal beaker. While stirring, 330 g of fly ash from the melting chamber with a high amorphous proportion were added and this suspension dispersed for a short time. The fly ash of the melting chamber had the following constituents by weight calculated as oxides: silicon dioxide 46%, aluminum oxide 30%, calcium oxide 5.3%, magnesium oxide 3.5%, potassium oxide 5.0% and sodium 1.0%. After dispersion, 30 g of amorphous aluminum oxide with an average particle size of 13 nm and 45 g of iron oxide pigment with an average particle size of 0.1 μm were stirred. After intensive agitation in order to homogenize, 60 g of water was added. The molar ratio of silicon dioxide / alkaline oxide was now 4.9 and the aluminum oxide content of 42 moles per 100 moles of silicon dioxide. The proportion of the calcium and magnesium oxides added was 20 moles per 100 moles of silicon dioxide. The resulting silicate suspension was immediately emptied onto the exposed surface of a recently cured concrete roof tile and dried for one day at room temperature. The concrete roof tile had a matt coating with an average thickness of 1 mm.

EXAMPLE DB EMBODIMENT 8 113 g of a 5 molar potassium hydroxide solution was added to 467 g of an aqueous alkaline silica sol with a solids content of 60% and an average particle size of 40 nm. The alkali silicate solution thus obtained was then dispersed for 5 minutes. The molar ratio of silicon dioxide / alkaline oxide was now 15.5. The preparation was then stored in a sealed polyethylene container at room temperature for about 1 hour. Then 60 g of pigment with an average particle size of 0.1 μa were added. The obtained mixture was dispersed for 5 minutes. Then 105 g of slag sand followed by a mixture of 84 g of mica with an average particle size of 26 μm and 126 g of calcite with an average particle size of 20 μm were shaken. This final mixture was homogenized and the resulting silicate suspension was placed in disc-shaped bodies with a diameter of 40 m, a height of 4 m and a weight of 15 g. These shaped bodies were cured for two days at room temperature. The configured bodies showed no cracks of any kind and had a lustrous surface.

EXAMPLE OF EMBODIMENT 9 60 g of water were added to the silicate suspension described in Example 8 and dispersed. The diluted silicate suspension was then sprayed on a recently burned clay roof tile and dried for one day at room temperature. The resulting coated clay roof tile had a coating with an average thickness of 0.1 mm and a glossy surface.

EXAMPLE DB REALIZATION 10 115 g of a 5 molar potassium hydroxide solution was added to 750 g of an aqueous alkaline silica sol with a solids content of 50% and an average particle size of 50 nm. The resulting alkali silicate solution thus obtained was then dispersed for 5 minutes. The molar ratio of silicon dioxide / alkaline oxide was now 23. Then the preparation was stored in a sealed polyethylene container for half an hour at room temperature. Then 86.5 g of a red iron oxide pigment with an average particle size of 0.1 μm was added. The obtained mixture was dispersed for 5 minutes. Then 150 g of slag sand followed by 303 g of mica with an average particle size of 36 μm were shaken. This mixture was finally homogenized. The resulting silicate slurry was immediately applied with a brush to the exposed surface of a recently cured concrete roof tile. The concrete roof tile obtained in this way was dried for one day at room temperature. The concrete roof tile had a red coating with an average thickness of 0.1 mm.

EXAMPLE DB REALIZATION 11 145 g of an alkaline solution of potassium silicate with a solids content of 45% by weight and an aolar ratio of silicon dioxide / alkaline oxide of 1.3 was added to 255 g of an aqueous alkaline silica sol recently produced with a solids content of 60% and an average particle size of 40 nm and dispersed for 15 minutes. The molar ratio of silicon dioxide / alkaline oxide was now 7.9. 40 g of a pigment with an average particle size of 0.1 μm followed by 70 g of slag sand were then rapidly stirred into this preparation. The resulting mixture was dispersed before the addition of 140 g of alcaline with an average particle size of 36 μm. Finally 40 g of water were added and the preparation was homogenized. Then the aqueous silicate slurry was sprayed onto the exposed surface of a freshly produced uncured concrete roof tile and then cured for 6 hours at 60 ° C. The obtained roof tile had a coating with an average dimension of approximately 0.1 mm.

EXAMPLE OF EMBODIMENT 12 The aqueous silicate suspension produced according to Example 11 was applied with a brush or brush to paint a degreased glass plate and a metal plate. These samples were dried for several hours at room temperature. The glass and metal plates obtained had a coating that adheres firmly without cracks with an average thickness of 0.3 mm.

Claims

R E I V I N D I C A C I O N S

1. - Silicate compound having at least one amorphous binder matrix containing alkaline oxide and silicon dioxide and also oxides from the group of aluminum oxide, calcium oxide, titanium dioxide, magnesium oxide, zirconium dioxide and / or boric oxide , characterized in that: the amorphous binder matrix contains from 4 to 25 moles of silicon dioxide per mole of alkaline dioxide; the alkaline oxide is Lithium oxide, sodium and / or potassium; and the amorphous binder matrix also contains, homogeneously distributed and per 100 moles of silicon dioxide, up to 80 moles of aluminum oxide and / or up to 45 moles of calcium oxide, titanium dioxide, magnesium oxide, zirconium dioxide and / or boric oxide.

2. Silicate compound according to clause 1, characterized in that the compound is produced from an alkaline silica sol with a solids content of 30-70% by weight.

3. Silicate coapuesto according to clause 2, characterized in that the compound is produced from an alkaline silica sol with an average particle size of less than 130 nm.

4. Silicate compound according to one of clauses 1 to 3, characterized in that the compound contains a crystalline filler of the class of layered silicates.

5. Silicate compound according to one of clauses 1 to 4, characterized in that the compound contains a crystalline filler of the calcite class.

6. Silicate compound according to one of clauses 1 to 5, characterized in that the compound contains slag sand and / or cement.

7. Silicate compound according to one of clauses 1 to 6, characterized in that the silicate compound contains glass powder with a calcium oxide content of at least 30% by weight, a silicon dioxide content less than 70% by weight and an aluminum oxide content of less than 20% by weight. 8.- Silicate compound according to one of the clauses 1 to 7, characterized in that the compound also contains coloring pigments. 9.- Silicate compound according to one of clauses l to ß, characterized in that the compound is applied as a coating to a substrate. 10. Silicate compound according to clause 9, characterized in that the substrate is a roof tile. 11. Silicate compound according to clause 9 or 10, characterized in that the thickness of the coating is on average between 20 μm and 2 mm, preferably 0.1 mm. SUMMARY The invention relates to a silicate compound having at least one amorphous matrix containing alkaline oxide and silicon dioxide and also containing oxides from the group consisting of aluminum oxide, calcium, titanium, magnesium, zirconium and / or oxide. boric. In order to provide a silicate compound which is suitable both for making a molding and a coating on a substrate, which resists the effects as well as the weather, especially alternating cycles of freezing and thawing and attack by acids, bleaches or contamination, it is proposed that the matrix amorphous binder contains from 4 to 25 moles of silicon dioxide, alkaline oxide formalin, the alkaline oxide is an oxide of the group consisting ^ 3e lithium, sodium and / or potassium oxide and the amorphous binder matrix also contains up to 80 moles of aluminum oxide and / or up to 45 moles of calcium oxide, titanium, magnesium, zirconium and / or boron oxide uniformly distributed per 100 moles of silicon dioxide.