JPH032831B2 - - Google Patents

Description

[Detailed description of the invention]

B. Field of Industrial Application The present invention relates to a method for producing a glazed calcium silicate molded body. B. Prior Art Glazed calcium silicate molded bodies are attracting attention as building materials, such as exterior materials, because of their beautiful glazed surfaces and good durability. The method for producing a glazed calcium silicate molded object is to use a calcium silicate molded object as a base material (hereinafter simply referred to as "base material").
The method used was to seal the surface and then glaze it to eliminate pores.
However, this method heats the glazed surface when applying the glaze.
When the base material is subsequently cooled, shrinkage cracks occur between the heated portion of the surface layer of the base material and the unheated portion of the deeper layer because the shrinkage rate is different between the heated portion and the deeper unheated portion. On the other hand, based on conventional experience that cracks do not occur in cement mortar (hereinafter simply referred to as "mortar") when the surface is coated with glaze, a method applying this technology, that is, a method in which mortar is applied to the base material and then glazed, has been attempted. It was done. However, this method was not put into practical use because cracks occurred at the interface (adhesive surface) between the base material and mortar due to poor adhesion of the mortar to the base material. In this manner, none of the conventionally employed methods has been able to solve the problem of cracks occurring in the base material or the interface. Therefore, as a means of suppressing the occurrence of cracks, the applicant proposed a method of providing a heat insulating layer between the base material and the glazed layer, that is, applying a mixture of phosphate adhesive, pearlite, and water to the surface of the base material. We proposed a method for producing a glazed calcium silicate molded body, which is heated and hardened to form a heat insulating layer and then glazed (Japanese Patent Laid-Open No. 129566/1983). C. Problems to be Solved by the Invention The method for forming the heat insulating layer suppresses the occurrence of cracks and has achieved its purpose to some extent. However, this method requires
Two heating and cooling processes are required, one for curing the phosphate adhesive to form a heat insulating layer and the other for applying the glaze, and the repeated heating and cooling process makes the process that much more complicated. It also had the disadvantage of large energy loss. D. Means for Solving the Problem The present inventors have proposed that the heat insulating layer be formed at room temperature so that the heating and cooling process only needs to be performed once in the glazing process, and that there is a difference in composition between the base material and the glazed layer. The present invention was achieved based on the knowledge that a glazed calcium silicate molded article without cracking on the base material or interface can be obtained by forming two heat insulating layers and then applying glaze. That is, in the present invention, a mixture of a hydraulic substance, an inorganic fiber, a water retention agent, and water is applied to the surface of a calcium silicate molded body (base material) to form a first heat insulating layer, and then a mortar kneaded material is applied. The method for producing a glazed calcium silicate molded article is characterized in that the second heat insulating layer is formed, cured and dried, and then glazed. The reason for providing the first heat insulating layer in the present invention is to block the heat of the second heat insulating layer from being transmitted to the base material in the glazing process, to integrate the base material and the second heat insulating layer, and to allow thermal expansion of the first heat insulating layer. This is to provide a buffering effect that absorbs. The substrate used in the present invention refers to a molded body made of calcium silicate, such as lightweight aerated concrete (ALC). Examples of the hydraulic substance include Portland cement, mixed cement, and super fast-hardening cement. Inorganic fibers are blended to enhance insulation and buffering effects, such as alkali-resistant glass fibers,
Examples include artificial or natural inorganic fibers such as carbon fiber, alumina fiber, steel fiber, and asbestos. Water retention agents are added to prevent water from being absorbed into the substrate when a fibrous mixture is applied to the surface of the substrate. ), polyvinyl alcohol (PVA), polyethylene oxide (PEO),
Examples include polyacrylamide (PAA). In addition to the above formulations, for example, when applying a glaze with a high melting point glaze or when it is necessary to reduce the thickness of the heat insulating layer, it is necessary to use a lightweight bone that does not impair adhesion to the base material. Material (e.g. perlite)
There is no problem in blending. Next, the blending ratio of the raw materials for forming the heat insulating layer will be explained. The inorganic fiber is preferably blended in an amount of 0.5 to 5.0 vol% of the total volume of the mixture mixed for the first heat insulating layer. If it is less than 0.5 vol%, the insulation effect and buffering effect will be small, and if it exceeds 5.0 vol%, the fibers will be difficult to disperse and uniform mixing will be difficult. The water retention agent is blended in an amount of 0.05 to 5.0 wt% with respect to the hydraulic substance. If it is less than 0.05 wt%, the water retention effect will be weak and water will be absorbed into the base material, which is not preferable. If it exceeds 5.0 wt%, it inhibits the hydration reaction of the hydraulic substance, which is not preferable. Water may be added to the extent that the mixture is soft enough to be applied, and as a guideline, the amount of water is 50 to 300 wt% based on the hydraulic substance. If it is less than 50 wt%, the fibrous mixture will be hard and difficult to apply to the substrate, and if it exceeds 300 wt%, the fluidity will be too high and it will be difficult to apply it to a predetermined thickness. The reason for providing the second heat insulating layer is that if the glaze is applied directly to the surface of the first heat insulating layer, the fibers exposed on the surface of the first heat insulating layer may change color during heating, resulting in an unintended pattern on the glazed surface, or if the glazed surface is too exposed. This is to prevent unsightly patterns from forming and to improve surface strength. The hydraulic material used for the second heat insulating layer is the first heat insulating layer.
It is the same as that used in the insulation layer. Commercially available artificial or natural sand is used.
The mixing ratio of sand and hydraulic substance is the same as that of normal mortar for plastering, and the ratio of sand to hydraulic substance is 60~
300wt% is preferred. If it is less than 60wt%, it will become a rich mortar, which will shrink more when hardened and cause minute cracks, which is undesirable.On the other hand, if it exceeds 300wt%, the water-cement ratio will become too large and the strength will decrease. This is not desirable. The amount of water blended is such that the mixture is soft enough to be applied, and is generally 30 to 70 wt% based on the hydraulic material.
If it is less than 30wt%, the mixture will not be uniform and it will be difficult to apply it. If it exceeds 70 wt%, the fluidity of the kneaded product becomes too high, making coating work difficult, and both are unfavorable. In order to ensure the strength of the molded article, it is preferable to reduce the amount of water and the number of air bubbles as much as possible, so there is no problem in adding a water reducing agent or an antifoaming agent as appropriate. The thickness of the first and second heat insulating layers may be set to the required thickness of the glazed base material, but at least in order to prevent the base material from cracking due to heating in the glazing process, Preferably, each heat insulating layer has a thickness of 3 to 10 mm. Next, a method for manufacturing a glazed calcium silicate molded body of the present invention will be explained. After applying the fibrous mixture for the first heat insulating layer to a predetermined thickness by sufficiently pressing it with a trowel on the surface of the base material that has been processed to the required dimensions, apply the mortar mixture for the second heat insulating layer to the surface with a trowel. Apply it evenly to a predetermined thickness without forming bubbles and cure. After the second insulation layer has hardened, the surface is sprinkled with a conventional glaze slip and allowed to dry. Next, after covering the surfaces other than the sprayed surface with a heat insulating material, the desired glazed calcium silicate molded body is obtained by heating in a conventional manner at a temperature at which the glaze melts. If a high-strength heat insulating layer is required, it is effective to apply the mortar mixture on top of a metal lath or the like on the first heat insulating layer. Next, the present invention will be explained with reference to examples. Examples Examples 1 to 3 Commercially available lightweight aerated concrete slabs ("Iton" manufactured by Nippon Iton Kogyo Co., Ltd.) were cut to obtain 4 base materials with a size of 60 x 60 x 10 cm. Also, cement and alkali-resistant glass were obtained. A fibrous mixture was obtained by mixing fibers, a water retention agent, perlite, and water in the proportions shown in Table 1.Furthermore, for 100 parts by weight of early strength Portland cement ("Dainippon Early Strength Cement" manufactured by Nippon Cement Co., Ltd.) A mortar mixture was obtained by mixing 160 parts by weight of river sand (produced in Fujikawa), 50 parts by weight of water, and 2 parts by weight of a high-performance water reducer ("Mighty 150" manufactured by Kao Corporation).The base material obtained as described above, Three glazed calcium silicate molded bodies were made using the fibrous mixture and the mortar mixture in the following manner. First, after moistening the surfaces of the three base materials,
Immediately, each of the three types of fibrous mixture was applied separately to a thickness of 5 mm by pressing with a trowel, and on top of that, the mortar mixture was applied to a thickness of 5 mm by pressing with a trowel so that the surface was flat, and then left for 24 hours. and cured. After curing, a slip prepared by dispersing a commercially available glaze ("LW-11a" manufactured by Nippon Horo Glaze Co., Ltd.) in water was sprayed onto the surface of the cured product and dried. After drying, cover the surface other than the sprayed surface with inorganic fiber ("Cow All" manufactured by Isolite Industries Co., Ltd.), and then
The glaze was fused to the mortar layer by irradiation with far infrared rays for 15 minutes so that the temperature reached ℃, and then allowed to cool. When we investigated the occurrence of cracks in each of the obtained glazed calcium silicate moldings, we found that there were no cracks in the fibrous mixture layer, mortar mixture layer, base material, fiber mixture layer, or base material itself, and the glazed surface was beautiful. It was finished. Comparative Example 1 The mortar kneaded material used in the examples was applied to a thickness of 5 mm on a substrate that had been moistened with water, and glaze was applied in accordance with the same procedure as in the examples. As a result of examining the occurrence of cracks in the obtained glazed calcium silicate molded article, it was found that many cracks had occurred in the base material, and cracks had also occurred between the base material and the mortar.

【table】

[Table] F. Effects of the Invention Conventionally, in the production of glazed calcium silicate molded bodies, a phosphate adhesive was applied to a base material and heated, and further heating was applied when applying the glaze. The fact that the heating process is performed twice in itself not only complicates the process, but also has the disadvantage that cracks are likely to occur due to heating, but the method of the present invention does not require heating to form a heat insulating layer. By using a non-hydraulic material, only one heating process is required, which not only simplifies the process, but also eliminates the occurrence of cracks in the base material and heat insulation layer of the glazed calcium silicate molded body. The surface can also be beautifully finished.

Claims (1)

[Claims] 1 Hydraulic substance on the surface of the calcium silicate molded body,
A method for producing a glazed calcium silicate molded body, which comprises applying a mixture of inorganic fibers, a water retention agent, and water, then applying a mortar mixture, hardening and drying, and then applying a glaze.