CS248488B1 - The method of glazing flat ceramic products with matt glaze - Google Patents

Abstract

The purpose of the solution is to improve the surface quality of matt glazes in the production of glazed flat ceramic products. The stated purpose is achieved by first coating the pre-fired shard with a layer of glossy glaze in an amount of at least 0.130 kg . . m~2. A layer of matt glaze in an amount of at least 0.440 kg . m-2 is then applied to the glazed shard. The time interval between the coating with glossy and matt glaze must be at least one second. This method of glazing is applied in the production of matt surfaces wherever flat ceramic products such as tiles, pavers and the like are produced.

Description

The invention relates to a method of applying a matt glaze to a pre-baked shard in the manufacture of flat ceramic products such as tiles, tiles and the like.

The matt glazing method used hitherto is operatively realized in such a way that the matt glaze layer is in an amount of 0,800 kg.nv in ² to 0,980 kg. m ~ ² is applied by a pouring device to a pre-baked shard. During firing, there is a mutual reaction between the shard and the matt glaze, so-called interlayer is formed. The properties of the matt glaze, especially its high surface tension and the interaction of the shard with the glaze during firing, have a decisive influence on the final appearance of the matt glaze surface. This may now be characterized as not well remelted, relatively restless with a considerable number of surface defects, craters, punctures, thus of poor quality. The present problem is currently solved by decorating the surface of the matt glaze with large-area decors, possibly with a spray, which partly obscure these surface defects of the matt glaze.

The above-mentioned drawbacks are eliminated by the glazing process of the flat ceramic products according to the invention, which is based on the fact that the pre-baked shard is first poured over a layer of glossy glaze in an amount of at least 0.130 kg. nv ² and a matt glaze layer of at least 0.440 kg is applied to the cullet. m ~ ² , the time interval between the shining topping and the frosting topping must be at least one second. The amounts and relative weight ratio of the applied glossy and matt glazes depend on the specific operating conditions and the type of glazed product. By varying the ratio of the glossy and matte glaze, it is possible to influence the final degree of surface finish maturation. The minimized time interval of one second between shining and matt glaze must be maintained so that the water from the shining glaze, when applied to the shake, soaks into the shard and thus the shining glaze is already a compact layer when glazed with matt glaze. This avoids mixing of the glossy and matt glazes with each other.

By introducing the glaze glaze coating before the glaze glaze itself, it is achieved that the glaze is not in direct contact with the glaze and thus the baking-matte glaze interaction and the effect of high surface tension of the glaze on the formation of surface defects are eliminated. is applied in classic icing, it is removed.

Such a method of matte glazing pouring has proven itself in operational tests of matte tile production. The surface of the matte glaze during the pouring process according to the invention can be characterized as perfectly smooth, well melted, practically free of surface defects.

Examples of application of said matt glazing method.

Example 1

Glazing is realized on the glazing line. A layer of glossy glaze in an amount of 0.220 kg is applied to the fired pore. nv ² and a matt glaze layer of 0.80 kg is applied to the cullet. m ^-2 , the time interval between the shining topping and the frosting topping was 4 s.

Composition and properties of glossy white glaze:

cover frit based on SiO2, B2O3 (ZFR 6 465) floated kaolin Sedlec sodium chloride sodium pyrophosphate density of glaze kinematic viscosity dry matter content

Composition and properties of white wt. 7 wt.

0.25 wt. 0.05 wt.

523.0 kg. m ~ ³ 2.0.10 -8 _m «. % _with 58 wt.

matt glaze:

cover frit based on SiO2, B2O3 (ZFR 6 465) dolomite Oslany floated kaolin Sedlec zinc white sodium chloride sodium pyrophosphate density of glaze kinematic viscosity dry matter content

66.5% wt. 9.0% wt. 3.2 wt.

21.3 wt. 0.2 wt.

0.23 wt. 1,630 kg. m ~ ³ 3.6.10 ^-6 m. s ¹

62.5% wt.

The glazed tiles are fired at a temperature of 960 ° C in a tunnel muffle furnace. The firing time is 22 h.

Example 2

The glazing process, the amount of deposits, and the time interval between the glossy and matt glaze are the same as in Example 1.

Composition and properties of glossy blue glaze:

cover frit based on S12,

B2O3 (ZFR 6 465) 81.0 wt.

transparent frit based on S1O2,

% B2O3 (ZFR 6 470) 10.0 wt.

Float kaolin Sedlec 7.0% wt.

blue coloring base

2.0 wt. 0.3 wt. 0.1 wt. 1,530 kg. m_ ³ 85.10 ~ ⁶ m ² .s “ ¹ 58% wt.

ZrSiV (K 20 468) sodium chloride sodium carbonate density of the glaze kinematic viscosity 1, dry matter content

4 3 4 8 9

Composition and properties of blue matt glaze:

cover frit based on S1O2,

B2O3 (ZFR 6 465) 66.0 wt.

dolomite Oslany 9.0% wt.

float kaolin Sedlec 3,2% wt.

zinc white 21.3% wt.

blue coloring base

0.5 wt. 0.2 wt. 0.23 wt. 1,628 kg. m ~ ³ 3.6. ^{6 6} m ² . 62.5 ° / wt.

ZiSiV (K 20 468) sodium chloride sodium pyrophosphate bulk density glaze kinematic viscosity dry matter content

The firing and firing times are the same as in Example 1.

The surface of the matt glaze in the glazing according to the invention appears to be perfectly smooth, matt, well remelted, practically free of surface defects.

The glazing method according to the invention is applied in the manufacture of matt surfaces, whether white or colored, in all plants producing flat ceramic products such as tiles, tiles and the like.

Claims (1)

A method for glazing flat ceramic products with a matt glaze, characterized in that the pre-baked shard is first poured with a layer of glossy glaze in an amount of at least 0.130 kg. m ² and a layer of matt glaze in an amount of at least 0.440 kg.mr ² is applied to the glazed pellet, which has to be separated by at least one second.