Field of the Invention

The invention relates to a silanization solution, in particular a silanization solution to silanize surfaces treated with tin-containing solutions, especially utilized in the production of mirrors, and the method of its preparation.

Background Art of the Invention

Currently known mirror production technology in which the silver layer is protected by a layer of copper, further protected by a layer of organic varnish. This is the oldest method used in the industrial mirror production.

Furthermore, a technology is known in which the relatively expensive copper layer is replaced by a cheaper adhesive solution, providing a connecting bridge between the silver layer and the varnish. This adhesive solution is either made of a single substance where one part of the molecule shows affinity to the silver layer, while the other part of the molecule shows affinity to the organic protective varnish. This creates two bridges, which are connecting the silver with the varnish via the molecule as benzotriazole is. The creation of the connecting bridge can be done with help of several substances, and thus more than two bridges are created, connecting the silver with the protective varnish. The most often used is tin chloride and silane (in this case 3-aminopropyltriethoxysilane) are used and applied sequentially, first tin chloride is applied onto the silver layer, where the tin is deposited, which is firmly bonded to the silver. Subsequently, silane is applied in the form of an aqueous solution and its hydrolytic product is anchored to tin using silicon. This creates a second bridge and the organic part of the hydrolytic product of silane is anchored to the varnish, thus forming a third bridge. These bridges provide good connection of the protective varnish with the silver coating.

The disadvantage of the prior art are high prices of silane, mainly caused by its lack on the market.

It is the object of the invention to replace silane with a better available and cheaper solution, providing a comparable or better quality. Disclosure of the Invention

The above-mentioned disadvantages are largely eliminated and the object of the invention is achieved by a silanization solution, particularly a silanization solution to silanize surfaces treated with tin-containing solutions, according to this invention, the subject matter of the invention is that it contains a solution of a lithium water glass compound and glycerine. Its advantage is in the formation of solid interlayers between the tin and the varnish, providing highly corrosion-resistant mirrors. Based on a CASS anti-corrosive test pursuant to EN-10-36 standard, the average corrosion does not exceed 80 pm without point defects. The maximum corrosion does not exceed 1 10 pm.

It is advantageous, if the silanization solution contains 10 to 90 wt.% of lithium water glass and 10 to 90 wt.% of glycerine. The advantage is the formation of a silanization concentrate that can be efficiently transported, while obtaining the final solution by diluting the concentrate with distilled water at the place of application.

It is further advantageous, if the lithium water glass has a molar ratio of SiOs/LisO from 1 to 7, while the most advantageous molar ratio of SiOs/LisO in the lithium water glass is 2.5. The advantage of such lithium water glass is its general availability. It contains the highest portion of lithium out of the commercially manufactured water glasses. Therefore, the lowest possible quantity of this water glass can be used for producing a silanization solution while maintaining the best silanizing properties.

It is highly advantageous, if the silanization solution further contains 1 to 90 wt.% of distilled water. It is beneficial that the silanization solution concentrate can be diluted so that the settings of the production line are exactly the same as with the silane used so far.

The above-mentioned disadvantages are largely eliminated and the object of the invention is achieved by the method of preparation of the silanization solution, particularly the method of preparation of the silanization solution specified above, according to the invention, the subject matter of the invention is that lithium water glass is mixed with glycerine. It is advantageous if 10 to 90 wt.% of lithium water glass and 10 to 90 wt.% of glycerine are mixed. Alternatively, it is advantageous if 10 to 80 wt.% of lithium water glass, 10 to 80 wt.% of glycerine and 10 to 80 wt.% of distilled water are mixed first.

Furthermore, it is advantageous, if the lithium water glass according to this method has a molar ratio of SiOs/LisO as low as possible. The advantage is in the fact that such water glass is most efficient, so that the content of the water glass in the silanization solution can be kept at the lowest possible level.

It is advantageous that the silanization solution and the method of its preparation according to this invention allow a very simple substitution of silane for treating the silver layer, which is also technically more beneficial. Available and affordable substances are used, while the adhesion of the protective varnish to the silver layer is provided by three substances. The first one remains the same as when applying silane, thus tin is deposited on silver from the aqueous solution of tin chloride. The second substance is lithium water glass, providing a connection between silicone and tin, and the third substance is glycerine that binds to water glass. This organic substance also provides a fourth bridge with an organic protective varnish. This system, created by three substances and four bridges, may at first sight appear to be more complicated as compared to the prior art. However, it ultimately provides a firmer connection of the protective organic varnish with the silver layer than the precedent methods. Application takes place in two steps. First is the application of aqueous solution of tin chloride onto a silver layer, where tin is deposited and firmly connected to silver. After rinsing with distilled water, the silanization solution according to the invention is subsequently applied instead of silane. This provides a bridge between tin and water glass, forming a second bridge. A third bridge is created between water glass and glycerine and a fourth bridge is formed between glycerine and the protective organic varnish. It is highly advantageous that the connection of lithium water glass and glycerine into one solution enables these two chemicals to be connected into one application, so that it allows smooth transition to this technology without having to modify the existing silvering line in any way.

Preferred embodiments of the invention

Example 1

The silanization solution contains 10 wt.% of lithium water glass and 90 wt.% of glycerine. The lithium water glass has a molar ratio of SiOs/LisO equal to 1 .

According to the method of preparation of the above-described silanization solution, 10 wt.% of lithium water glass and 90 wt.% of glycerine is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 1 . Everything is mixed properly. The silanization solution needs to be further pre-diluted with distilled water in a ratio of 1 :10 and dosed at 1 litre of prediluted silanization solution per hour into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 60 ml of silanization solution concentrate.

Example 2

The silanization solution contains 90 wt.% of lithium water glass and 10 wt.% of glycerine.

The lithium water glass has a molar ratio of SiOs/LisO equal to 7.

According to the method of preparation of the above-described silanization solution, 90 wt.% of lithium water glass and 10 wt.% of glycerine is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 7. Everything is mixed properly. Then 2 litres of the silanization solution per hour are dosed into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 1 ,200 ml of silanization solution concentrate.

Example 3

The silanization solution contains 55 wt.% of lithium water glass and 45 wt.% of glycerine.

The lithium water glass has a molar ratio of SiOs/LisO equal to 2.5.

According to the method of preparation of the above-described silanization solution, 55 wt.% of lithium water glass and 45 wt.% of glycerine is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 2.5. Everything is mixed properly. The silanization solution needs to be further pre-diluted with distilled water in a ratio of 1 :10 and dosed at 1 litre of pre- diluted silanization solution per hour into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 60 ml of silanization solution concentrate.

Example 4

The silanization solution contains 10 wt.% of lithium water glass, 10 wt.% of glycerine and 80 wt.% of distilled water.

The lithium water glass has a molar ratio of SiOs/LisO equal to 1 .

According to the method of preparation of the above-described silanization solution, 10 wt.% of lithium water glass, 10 wt.% of glycerine and 80 wt.% of distilled water is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 1. Everything is mixed properly. Then 1 litre of the silanization solution per hour is dosed into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 600 ml of silanization solution concentrate.

Example 5

The silanization solution contains 80 wt.% of lithium water glass, 10 wt.% of glycerine and 10 wt.% of distilled water.

The lithium water glass has a molar ratio of SiOs/LisO equal to 7.

According to the method of preparation of the above-described silanization solution, 80 wt.% of lithium water glass, 10 wt.% of glycerine and 10 wt.% of distilled water is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 7. Everything is mixed properly. Then 2 litres of the silanization solution per hour are dosed into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 1 ,200 ml of silanization solution concentrate.

Example 6

The silanization solution contains 10 wt.% of lithium water glass, 80 wt.% of glycerine and 10 wt.% of distilled water.

The lithium water glass has a molar ratio of SiOs/LisO equal to 3.

According to the method of preparation of the above-described silanization solution, 10 wt.% of lithium water glass and 80 wt.% of glycerine and 10 wt.% of distilled water is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 3. Everything is mixed properly. Then 1 litre of the silanization solution per hour is dosed into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 600 ml of silanization solution concentrate.

Example 7

The silanization solution contains 40 wt.% of lithium water glass, 30 wt.% of glycerine and 30 wt.% of distilled water.

The lithium water glass has a molar ratio of SiOs/LisO equal to 2.5.

According to the method of preparation of the above-described silanization solution, 40 wt.% of lithium water glass, 30 wt.% of glycerine and 30 wt.% of distilled water is mixed, while the lithium water glass has a molar ratio of SiOs/LisO equal to 2.5. Everything is mixed properly. The silanization solution needs to be further pre-diluted with distilled water in a ratio of 1 :10 and dosed at 1 litre of pre-diluted silanization solution per hour into a distilled water flow of 200 I per hour. This solution is used to treat a mirror surface of 1 ,570 m ² per hour. The spraying is applied onto the silver layer, which was treated by the aqueous solution of tin chloride, and perfectly rinsed off by distilled water. For 1 ,000 m ² of mirrors was used 60 ml of silanization solution concentrate.

Industrial Applicability

The silanization solution according to the present invention can be used to silanize silver- coated layers of mirrors in order to improve the adhesion of the protective layer of varnish or paint to the silver. The silanization solution can also be used to improve varnish adhesion directly to the glass in Lacobel-type products.