JPS5921571A - Manufacture of ceramic tile - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing glazed porcelain/stoneware tiles used for interior decoration or floors for the purpose of energy saving.

Traditionally, glazed porcelain or stoneware tiles are produced by pressure molding clay prepared from raw materials such as feldspar, pottery stone, or clay, and bisque firing at low temperatures as necessary, or directly without bisque firing. After drying, glaze was applied, and the glazed glazed bodies were placed horizontally one by one in a firing tool, stacked in multiple stages, and fired at high temperatures for a long time until they were turned into porcelain or stoneware. A heavy firing tool consumes most of its heat, resulting in poor thermal efficiency, and there is a strong desire to improve this. In addition, the method adopted by conventional processing companies is to heat the molded body that has been dried after molding by flat firing or vertical firing at high temperature, reduce the water absorption rate of the fired body to 1% or less, and turn it into porcelain. This method involves heating and glazing the porcelain body, then heating and drying it, and then firing the glaze at a low temperature. In this method, in order to glaze a porcelain body that absorbs almost no water, it is necessary to heat the porcelain body to immediately remove moisture, and at the same time to prevent the glaze from flowing out from the tile surface and to prevent it from remaining on the tile surface. Therefore, it is necessary to adjust the viscosity of the glaze by adjusting the amount of glaze applied and adding a binder. Furthermore, when the binder is added, drying after glazing depends only on the evaporation of water, so the amount of drying is small and therefore requires technically difficult work such as heating.

The present invention is a method for manufacturing porcelain/stoneware tiles that eliminates these drawbacks, and will be described below with reference to Examples. The raw materials used in the present invention include all or part of the plastic raw materials, non-plastic raw materials, and auxiliary materials described below. Plastic raw materials include clay, kaolin, bentonite, sericite, Rouseki, talc, etc. Non-plastic raw materials include silica, feldspar, natural glass, etc., solvents, pottery stone, limestone, etc., and auxiliary materials include binders, reducing agents, etc. Abrasives, etc. Part or all of this raw material is wet-pulverized using a trommel to a particle size range shown in Table 1 on the next page, dehydrated using a filter press, and then dried using a drying equipment such as a flash-pulverizing dryer, a granule crusher, or a rotary dryer. So 3~
Dry and granulate to 10% to obtain clay for molding. Alternatively, a slurry with a high specific gravity is prepared and dried and granulated directly in a spray dryer to a concentration of 3 to 10% without passing through a filter press to obtain a clay having a particle size distribution suitable for a molding machine. This clay is pressure molded at as high a pressure as possible (300 kgf/cm2 or higher) to obtain a dense molded body.

Table 1 Particle size range (μ) 1 or less 1-5 5-10 Particle size distribution (
wt%) 10~20 15~30 15~2510~
20 20-30 30 or more 20-25 10-15 10- The obtained molded element is bisque fired to give a water absorbency of 1% or more to obtain a biscuit element. When firing in a tunnel kiln, this bisque firing method avoids the use of firing tools such as saggers as much as possible in order to save energy, stacks many molded bodies directly on the trolley 1, and obtains a sufficient drying process. It is preferable to fire at a low temperature of 1100°C, but it may be fired at a higher temperature depending on the clay formulation. Furthermore, in order to prevent the stacked tiles from deforming and fusing together, it is necessary to obtain an unglazed ceramic body that retains water absorption with a water absorption rate of 1% or more. It is also possible to bisque fired by stacking one or several sheets directly on a roller without using a firing tool by rapid flat firing using a single-stage Roller Hearth Kiln (hereinafter abbreviated as RHK) or the like. There is also a method in which the material is bisque-fired on a lower roller in a multi-stage RHK, glazed continuously on a belt, and then automatically inserted again onto the upper roller of the same RHK to quickly final-fire it into porcelain or stone.

The unglazed ceramic body thus obtained is hung without heating,
Glaze is applied by a conventional method such as spraying or using a centrifugal glazing machine to obtain a glazed body. Since the unglazed ceramic body has a water absorption of 1% or more, it does not require heating.

The glazed rope body is directly inserted directly from the glazed belt into the RHK for final firing without using a firing tool such as a setter.
The tiles are fired and inserted in a residence time of less than 2 hours from the entrance to the exit, and the tiles are turned into porcelain or stoneware. The residence time for firing was set to within 2 hours in order to move the tiles quickly on the rollers of the RHK so that they would not be deformed at high temperatures. According to the applicant's experiments, this residence time is possible even if it is within 20 minutes;
The residence time of 60 minutes shown in the graph of the firing conditions for K is optimal as it causes very little deformation of the tiles and less occurrence of defects such as porosity. After this firing, in order to prevent hot deformation due to ripening, it is necessary to rapidly cool or rapidly pass the time during which deformation begins.

According to the present invention, the following effects are achieved.

(1) If you use a large amount of conventional firing tools such as saggers and fire at high temperatures for a long time, the tile product will yield approximately 2500K per 1Kg of product.
Cal to 4000 Kcal of energy was required, but in the present invention, the bisque firing temperature is kept low in order to retain water absorption with a water absorption rate of 1% or more, and heating of the bisque fired body before glazing is not a concern. 1000Kcal to 1500Kcal per 1Kg of tile product, depending on the fact that a sagger is not used during the main firing, and the main firing takes less than 2 hours.
1, contributing greatly to energy conservation.

(2) When glazing is applied to an unglazed terracotta body that retains water absorption with a water absorption rate of 1% or more, the glaze is fixed to the terracotta terracotta body, so printing such as bottom print, top print, thick print, overlapping print, water-repellent relief print, etc. In addition to the techniques, various decorative techniques for design tiles can be obtained, such as uneven glazing techniques such as gradation glazing, tassel glazing, and spotted glazing.

(3) Since the glaze is applied to an unglazed ceramic body with a water absorption rate of 1% or more, there is no need for heating and drying before and after glazing, there is almost no need to adjust the viscosity of the glaze, and the weight of the glaze can be arbitrarily selected.

[Brief explanation of drawings]

FIG. 1 is a graph showing the firing temperature and firing time in the RHK during the main firing of the present invention. Patent applicant Terumi Ina, CEO of Ina Seito Co., Ltd.

Claims (1)

[Claims] 1. Plastic raw materials such as clay, kaolin, sericite, Rouseki, talc, etc., and/or solvents such as silica, feldspar, or natural glass, non-plastic raw materials such as pottery stone, limestone, and/or binders;
Add all or part of auxiliary materials such as anti-friction agents, pulverize dry or wet, and adjust the moisture content to 3 to 10% during dehydration and drying. Pressure mold the clay in a semi-dry or dry process. The molded body is bisque-fired to give a water absorption rate of 1% or more to obtain a bisque-fired body, the bisque-fired body is glazed without heating, and the glazed body is transferred to the entrance of a roller hearth kiln. A method for producing a porcelain/stoneware tile, which is characterized in that it is fired for a residence time of less than 2 hours from the time to the exit, and then turned into porcelain or stoneware, and then rapidly cooled or rapidly passed through a time period during which deformation begins.