CS273102B1 - Sintered glass for lustrous covering glazes production with increased hydrolytic resistance conditioned on boron trioxide reduced content - Google Patents

Abstract

The sintered glass contains by weight: silicon oxide SiO2 57.O to 65.0 %, aluminium oxide Al2O3 2.0 to 6.5 %, calcium oxide CaO 1.0 to 5.5 %, boric oxide B2O3 7.0 to 13.5 %, sodium oxide Na2O 0.5 to 5.0 %, potassium oxide K2O 0.5 to 7.0 %, barium oxide BaO l.5 to 6.5 %, zirconium oxide ZrO2 0.5 to 10.0 %. It can also contain up to 5 % zirconium oxide ZnO, up to 4.0 % magnesium oxide MgO, up to 4.0 % calcium fluoride CaF2 and up to 4.0 % sodium fluorosilicate Na2SiF6. The reduction of the content of boric oxide to 7.0 to 13.5 % by weight led to an increase of the hydrolytic resistance of the sintered glass when grounding wet to glaze and, during the burning cycle of 30 minutes to 16 hours with retardation of 5 minutes to 3 hours to a maximum temperature of 1,050 to 940 degrees C, the glazes showed no surface faults, such as non-homogeneous opacity, diffuse schliers, uneven thickness, waves and small punctures.

Description

CS-273102 Bl

The invention relates to a frit for the production of glossy opaque glazes and to an increased hydrolytic resistance due to reduced boron oxide content,

The frits and the ee doeud shiny glazes made therefrom are made by melting a strain derived from a mixture of quartz, feldspars, borax, boric acid, marble, limestone, zirconium, kaolin, dolomite and some optional ingredients such as barium, zinc, lead, lithium , sodium fluorosilicate and calcium fluoride.

The boron content of boron oxide is about 15% by weight. This amount of boric oxide in the presence of alkali leads to a decrease in the hydrolytic resistance of frlts in wet grinding to glazes, to the formation of colloidal particles, resulting in surface defects in glazed articles after firing, manifested by inhomogeneity glaze strength, ripples and small punctures.

For these reasons, it has been expedient to find a hydrolytically resistant frit which gives glazes with a quality surface without defects whose presence is conditioned by hydrolysis during wet grinding. The way to this was to adjust the oxide composition of the frit. The objective was achieved by developing a frit according to the invention and by reducing the content of boron oxide to prepare glossy opaque glazes. The frit was prepared on the basis of silica, alumina, calcium, sodium, potassium, boron, barium and zirconium, with possible additions of magnesium, zinc, calcium fluoride and sodium fluorosilicate.

The principle of the invention is that the frit contains by weight:

silica alumina calcium oxide SiO ₂ and i ₂ o ₃ CaO 57.0 to 55.0% 2.0 to 1.0 to 6.5% 5.5% boron trioxide ^B 3 ° 3 7.0 to 13.5% sodium oxide At ₂ 0 0,5 to 5.0% potassium oxide 0,5 to 7.0% barium oxide BaO 1.5 to 6.5% a zirconium dioxide Zr0 ₂ 0,5 to 10.0% other beds include: zinc oxide ZnO tracks up 5.0% magnesium oxide MgO tracks up 4.0% calcium fluoride CaF ₂ tracks up 3.0% and / or sodium fluorosilicate Na ₂ SiF ₆ tracks up 4.0%.

By reducing the boron oxide content to 7.0 to 13.5 wt. Improved hydrolytic resistance of the frit during wet grinding on the glaze, eliminating the formation of colloidal particles, and as a result eliminated the inhomogeneity of haze (whiteness), dull smudges, uneven glaze thickness, waviness and tiny glazed surface in the burning cycle of 30 minutes up to 16 hours and hold for 5 minutes to 3 hours at a maximum temperature of 1050 ° C to 940 ° C. Sources of oxides in the frit were raw materials used in the manufacture of ceramic goods: quartz, sodium and potassium feldspar, boric acid, borax, soda, potash, kaolin, limestone, marble, dolomite, zirconium, barium carbonate, possibly zinc white, magnesite, calcium fluoride and sodium fluorosilicate.

The invention is further illustrated by specific examples of frit compositions according to the invention. all of said compositions being by weight.

Example 1

A strain of composition was prepared:

silica 63.0% _t alumina 5.2%, calcium oxide 4.8%, sodium oxide 4.5%, potassium oxide 5.2%, boron oxide 7.5 SS, zirconia 7.0% and oxide barium 2.8% · Frit for white opaque glossy glaze was prepared by melting at 1,350 to 1,550 ° C for 0.5 to 4 hours and used to prepare the glaze for cullet.

Example 2

A strain of composition was prepared:

CS 273102 B1 silica 62.5%, alumina 3.0%, · calcium oxide 2.5%, magnesium oxide 1.5%, sodium oxide 2.0%, <potassium oxide 4.0%, zinc oxide 4 , 0%, barium oxide 3.5%, zirconium oxide 8.0%, boron oxide 9.0%, Frlta for white opaque glossy glaze was prepared by melting at temperatures between 1 350 ° C and 1 550 ° C for 0.5 up to 4 hours and used for preparation of glazes for cullet cullet ·

Example 3

A strain of composition was prepared:

silica 60.6%, aluminum oxide 3.0%, sodium oxide 2.0%, potassium oxide 5.1%, barium oxide 2.9%, zirconium dioxide 8.1%, boron oxide 10.5%, Calcium oxide 2.0%, Sodium fluorosilicate 1.0%, Magnesium oxide 1.3%, Zinc oxide 3.5% · Frlta for white opaque glossy glaze was prepared by melting at temperatures from 1 350 to 1 550 ° C for 0, 5 to 4 hours and used to prepare the glaze for cullet.

The glazes prepared from the frits of Examples 1 to 3 by wet grinding were hydrolytically resistant and showed no surface defects after firing.

The burrs not glazed with glazes prepared from the frits of the examples were fired for 30 min to 16 hours with a hold time of 5 minutes to 3 hours at a maximum temperature of 1050-940 ° C. The resulting glossy covering glazes on cullet were resistant to sudden grains of temperature test) 150 to 200 ° C at a quality surface.

Claims (2)

OBJECT OF THE INVENTION CLAIMS 1. A filament for the production of shiny glazes having increased hydrolytic resistance due to reduced content of boric oxide on the basis of silicas, alumina, calcium, sodium, potassium, barium, zirconium or boric oxide, characterized in that it contains by weight: silica Si0 ₂ 57.0 to 65.0% aluminum oxide ^Al 2 ° 3 2,0 to 6.5% calcium oxide CaO 1.0 to 5.5% boron trioxide ^θ 2 ° 3 7.0 to 13.5% sodium oxide At ₂ 0 0,5 to 5.0% potassium oxide K ₂ 0 0,5 to 7.0% barium oxide BaO 1,5 to 6 »5% zirconium dioxide ZrO ₂ 0,5 ež 10.0% 2. A frit according to claim 1, characterized in that it contains traces of up to 5.0% by weight. % zinc oxide ZnO, traces up to 4.0 wt. MgO, traces up to 3.0 wt.%, calcium fluoride CaF _2, and traces up to 4.0 wt. sodium fluorosilicate NagSiFg., either singly or in any combination thereof.