JPH0369544A - Production of plain tile - Google Patents

Abstract

PURPOSE:To reduce shrinkage at the time of firing, to improve strength and to prevent the occurrence of cracks and strain by mixing chamotte with clays and slag in a prescribed ratio, press-molding the resulting powder in the dry state and firing the molded body. CONSTITUTION:50-70wt.% chamotte is mixed with 10-30wt.% clays and 10-30wt.% slag. The resulting powder is press-molded in the dry state and the molded body is glazed and fired. Since the powder hardly contains water, shrinkage is extremely reduced at the time of firing, the occurrence of cracks and strain is nearly prevented and the strength of a tile is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application The present invention relates to a method for manufacturing flat roof tiles such as Western roof tiles.

Problems to be solved by conventional techniques and inventions Generally, flat ceramic products such as tiles are formed by dry pressing, then glazed and fired, but cracks and distortions occur due to shrinkage during firing. Therefore, the limit is around 300mm square tiles, and tiles larger than that have poor yields and are difficult to manufacture, and flat tiles that require a size of 400mm square or more have the disadvantage of being expensive.

Means for Solving the Problems As a means for solving these problems, the present invention provides a powder mixture of 50 to 70% by weight of chamotte, 10 to 30% by weight of clay, and 10 to 30% by weight of slag. After dry press molding, it is glazed and fired.

Functions and Effects of the Invention The present invention has the above-mentioned structure, and since the main ingredients are chamotte and slag, which contain almost no moisture, shrinkage during firing is extremely small, and cracks and distortions are difficult to occur. In addition, the slag acts as a sintering aid, making it possible to produce high-strength and thin products.

In the present invention, chamotte is set at 50 to 70% by weight because if it is less than this range, shrinkage during firing becomes large and cracks and distortions are likely to occur.On the other hand, if it is too much, it becomes porous and has high water absorption. This is because clay is not suitable as a roof tile, and the reason why clay is set at 10 to 30% by weight is that if it is less than this range, the bonding strength will be weak and forming will be difficult, whereas if it is too much, it will be difficult to release from the press mold. Furthermore, the reason why the slag is set at 10 to 30% by weight is that if it is less than this range, the sintering force will be small and the strength will be insufficient, whereas if it is too much, the hardness will be too high and the workability will be poor. This is because it decreases.

Example 60% by weight of chamotte, 20% by weight of Mizunami Honbushi clay, and 20% by weight of crushed slag were mixed, and the mixture was dry pressed to a length of 46 mm.
When a base material of 0 mm, width 303 mm, and thickness 13 mm was formed and fired at 1300°C after glazing, the bending strength was 34.
With a weight of 7.6 kg and a water absorption rate of 4.9%, it has extremely excellent properties as a roof tile, and shrinkage due to firing is extremely small at 0.65%, resulting in no cracking or distortion, resulting in a high yield. It was done.

Claims (1)

[Claims] Shamotsu 50-70% by weight, clay 10-30% by weight
A method for producing a flat tile, which comprises dry press-molding a powder mixed with 10 to 30% by weight of slag, then glazing and firing.