WO2004031087A1

WO2004031087A1 - Ceramic glaze surface coating

Info

Publication number: WO2004031087A1
Application number: PCT/TR2002/000062
Authority: WO
Inventors: Nail SEVINÇ; Oktay Beskardes
Original assignee: Serel Seramik Sanayi Ve Ticaret AS
Current assignee: Serel Seramik Sanayi Ve Ticaret AS
Priority date: 2002-10-07
Filing date: 2002-10-07
Publication date: 2004-04-15
Anticipated expiration: 2005-04-07
Also published as: GB2411171A8; GB2411171A; AU2002343320A1; GB0509211D0; TR200501273T2; GB2411171B; DE20221215U1

Abstract

The ceramic surface coating of the present invention is used for the coating of the surfaces of such sanitary ceramic ware as closets, reservoirs, wash-basins, wash-basin pedestals, bidets, etc., as well as for all kinds of ceramic products. The ceramic surface coating of the present invention may be used for all kinds of ceramic material, preferably for the coating of the surfaces of such sanitary ceramic ware as toilet bowls, cisterns, wash-basins, pedestals, bidets. As the ceramic ware is used in such environments that require more hygienic considerations, it has to be cleaned easily and hard to be stained. The roughness of the surfaces, which leads to the staining of the ceramic surface, is tried to be reduced. The surface of the ceramic ware, according to the present invention is coated with a coating used to eliminate the roughness, which does not contain any opacifying, crystal-forming material.

Description

CERAMIC GLAZE SURFACE CQATING

The present invention relates to a ceramic glaze surface coating which is stain resistant and easy tσ clean. The present invention particularly relates to coating the surfaces of sanitary ceramics with this coating.

In the state of art, for the production of ceramic, the ceramic surface is coated with a glaze comprising 5 % and 15 % of an opacifying material for example Zr₂Siθ4 and baked at a temperature ranging between 12Q0°C and 1250°C. Said opacifying material does not completely dissolve in glaze structure but instead it crystallizes and gives the white and opaque appearance to the glazed Surface. Furthermore, since the opacifying material contained in the glaze is not dispersed homogeneously in the molten glaze, it is diffused to the surface in the form of crystals. These crystals form surface roughness (Figure 1), The rough surfaces of the ceramic products, created due to the opacifiers, are stainable and hold dirt in the course of time because of the particles trapped in the pores formed on the rough surfaces. Numerous studies have been made on various coating methods aiming at obtaining stain-resistant and easy-to-clean surfaces.

The most common method among them is characterized with coating or sillylating the ceramic product with a polymeric material based on its water - repellency. By virtue of said coating hydraulic liquids poured over the qeramic surface, flow away as they cannot stay on the cei'amic surface due to the low surface energy of the coating. However, the ceramic products are not only exposed to water, they are also exposed to other pollutants (contaminants). The water-repellent polymeric coatings are silicon-based. Such materials are cdated on the ceramic surface by a simple spraying or dipping methods and the product is usually subjected to a drying treatment at a temperature ranging between 20° C and 200°Cj depending on the type of the silicone material used. One example of atypical state of the art range of the glaze compositions are shown below:

The water-repellent coatings do not act i the same way against other contaminants and these polymeric coatings which have a tendency towards greasy/fatty mixtures, are more difficult to clean as compared to the ceramics which are not coated. Moreover, stich ceramic products which are coated with a Waterrrepellent polymeric material, are not resistant against harsh cleaners like hypochloride and its derivates and to mechanical cleaning agents of powder form and the like.

Therefore, it is not possible to prevent the ceramic surface from being easily contaminated or stained and from housing bacteria, due to the surface roughness of the uncoated ceramic products and the nonresistance of the ceramic products coated with silicon-based polytoerip coating, against detergents, and consequently this leads to the excessive consumption of polluting material, detergents and disinfectants. When a lead - pencil test is applied on the ceramic products of the state of art, it is seen that the pencil leaves a significant trace on the surface. This trace is formed due to the reason that th& ceramic surface has a rough structure and its cleaning becomes more difficult as the depth of the pores increases.

The object of the present invention is to obtain a ceramic material that is coated with a stain - resistant and easy-to-clean coating.

Another object of the present invention is to produce a ceramic product with a smooth surface.

Yet another object of the present invention is to produce a hygienic ceramic product with a longer service life, which requires less maintenance.

Another object of the present invention is to obtain a ceramic product that can be cleaned by using a smaller amount of water and cleaning substances.

The ceramic surface coating realized to attain said objectives of the present invention has bέen illustrated in the attached drawings, wherein:

.Figure 1, is the view of a cerarnic surface coated with a prior coating art, as taken by an optical microscope

Figure 2i is the view of the new cerarnic surface coating present invention as taken by an optical microscope.

The ceramic surface coating of the present invention is used for the coating of the surfaces of such santitary cerarnic ware as closets, reservoirs, wash-basins, wash-basin pedestals_*, bidets, etp., as well as for all kinds of ceramic products.

The ceramic surface coating of the present invention may be used for all kinds of ceramic material, preferably for the coating of the surfaces of such sanitary ceramic ware as toilet bowls, pisterns, wash-basins, pedestals and bidets. As the ceramic ware is used in such environments that require more hygienic considerations, it has to be cleaned easily and hard to b_je stained. For this reason, the roughness of the surfacesi, which leads to the staining of the ceramic surface, is tried to be reduced. The surface of the ceramic ware, according to the present invention is coated with a coating used to eliminate the roughness, which does not contain any opacifying and crystal-forming material.

The coating is applied on the ceramic material which has been subjected tp a pre-bakiήg treatment, by spraying or dipping a film of approximately 10 to 100 μm thickpess. After this coating step, the ceramic material, is baked s^epwise in an oven, at a temperature range between 1100°C and 1220°C until the surfape coating melts in vitrified phase, and the substrata is coated with, a glaze with less surface roughness and consequently a stain/dirt-resistant surface behaving ablatively (Fig. 2).

The ceramic surface poating according to the present invention comprises 45-60 % of SiO₂ , 5-15 % of AlO₃, 4-10 % of CaO, 0.1-2 % of MgO, 1-4 % of N₂O, 1-4 % of K₂O, 10-22 % of B₂O₃ or Na₂CO₃ fluximer compounds. Among these compounds, MgO and K₂O are used optionally.

The chemical compounds of the present invention constituting the coating are as follows:

As the roughness of the ceramic surface coated with the surface coating of the ptesent invention is reduced, the growth and colonization areas of the bacteria, are also reduced to an insignificant degree.

The rates of soiling and contamination of the peramie surface have been determined by conducting various tests op the said surface. These tests are respectively, lead-penciltest, cleaning- with- water test, and service life (durability) test.

In the lead_τpencil test, a pencil is used to draw on the cerarqic surface but it hes been found put that is was very difficult to draw or write on the surface of said product and that it could be easily removed by using a dry dcloth, wirhout aiηy remaining traces.

}n he 'cleaning with water' test, a mixture of burnt motor oil and edible oil has been applied on the surface pf the product, and then this has been tried to be cleaned by using only water. As a result, it has been seen that said heavy contaminants could easily be cleaned and removed by using only water.

In the service life (durability) test, methylene blue and malachide green, cleaning of which is very difficult by only using water, have been added to the previous suspension consisting of a mixture of burnt motor oil and edible oil and are applied to the ceramic surface as a contaminant. Consequently, this dirt has easily been removed by using a small amount of detergent.

Claims

1. A ceramic material characterized with a coating which contains no crystal forming material ^nd which is applied on the surface of the r)re-baked product with a thickness of 10 μ to 100 μm, and which is then baked stepwise at a temperature ranging between 1100° C and 1220°C until it melts and becomes vitrified, in order to eliminate the surface roughness.

2, A ceramic material as defined in claim 1, characterized with a coating applied in order to eliminate the surface roughness, comprising 45-60 % of SiO₂ , 5-15 % of AlO₃, 4-10% of CaO, 1-4 % of N₂O and 10-22 % of B₂O₃ or Na₂CO₃ compounds.

3, A ceramic material as defined in claim 2 characterized with a coating also comprising 0.1 -2 % of MgO, compound.

4. A ceramic material as defined in claim 2 and 3 characterized with a coating also comprising 0.1-2 % of K₂O, compound.

5. A ceramic material as defined in claim 1 and 2, characterized with a coating applipd on the surfaces of sanitary ceramic ware.