JPH0526751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing fiber-incorporated ceramic bodies.

It is generally known to mix fibrous materials as reinforcing materials in order to increase the strength of molded bodies of synthetic resin and concrete products. For example, mixing glass fiber with synthetic resin, or mixing synthetic resin fiber or glass fiber as a raw material for reinforced concrete. Since the fibers are randomly mixed in the molded article in their original shape, the strength of the fibers is added to the molded article, improving its strength against tension, impact, and bending.

The method of the present invention is to improve the brittleness, which is the inherent weakness of ceramic, by mixing such strength fibers into ceramic, and to improve the strength against bending, deflection, or impact, thereby providing a flexible ceramic body. It was developed in

Generally, the ceramic molding method involves molding the dough,
Normally, the process of drying and firing is used, and when forming the dough, it is easy to distort and bend because it is an unfired clay product, so when handling this unfired molded product, care must be taken to maintain its shape. requires attention,
When drying, care must be taken to avoid cracking and deformation due to drying shrinkage. Also, firing is at 1000℃~1300℃
It was necessary to pay attention to shrinkage due to the long duration of the process at high temperatures around ℃. As ceramics are fired at high temperatures, the synthetic fibers and glass fibers that are mixed into conventional ceramic products such as cement and concrete are carbonized or melted and lose their form as fibers, meaning that the purpose of reinforcement cannot be achieved. It is said that it is difficult to mix fibers into ceramics.

In the method of the present invention, a ceramic molded body is formed by mixing fibers with a low melting point such as synthetic fibers and glass fibers with fibers that do not melt and deform even at high temperatures such as firing temperatures, such as calcium silicate fibers. This allows the dough to retain its shape before baking and has flexibility after baking.

In other words, the calcium silicate fibers mentioned above are so-called mineral fibers, and although they are short, brittle, and have poor stretchability, they do not melt and deform at 1000 to 1300°C, which is the firing temperature for ceramics. On the other hand, the length of synthetic fibers and glass fibers can be determined freely, and they have strong properties against tension, but synthetic fibers have a tensile strength of 100~
It melts at about 280°C and carbonizes at temperatures higher than that, and it is impossible for glass fiber to melt at temperatures above 600°C and maintain its fiber form.

The present invention incorporates low-melting point fibers with different properties and high-temperature shape-retaining fibers that maintain their shape even at high temperatures into ceramic raw materials, thereby making it easier to form and dry fabrics. Utilizing the characteristics of low-melting point fibers, it prevents deformation and distortion of the dough molded body, as well as prevents the occurrence of cracks due to drying, and after firing, the brittleness of the ceramic body is improved by intervening high-temperature shape-retaining fibers. Organic low melting point fibers such as synthetic fibers are carbonized during firing and their existence is eliminated, but inorganic low melting point fibers such as glass are melted and deformed during firing and retain their shape as fibers. Although it is lost, it exists as a molten product and acts as a binder between the high-temperature shape-retaining fibers, making the flexibility of the ceramic molded article even more effective.

In the present invention, low-melting point fibers include various synthetic fibers, pulp, and asbestos, and high-temperature shape-retaining fibers include calcium silicate fibers, silicon carbide fibers, alumina fibers, and mica fibers. However, calcium silicate fibers are suitable in terms of price and handling, and glass fibers are suitable as fibers that melt during firing.

Also, the amount of low melting point fibers such as synthetic fibers mixed into each raw material clay should be very small;
It is 0.3 to 2% by weight based on clay, and the amount can be adjusted freely in consideration of the strength, weight, and flexibility of the ceramic body as a product for high-temperature shape-retaining fibers, and is 0.5% by weight.
It is possible to mix up to 80% by weight. Further, even when glass fiber is mixed, it is preferable to use a very small amount since it is present as a binder. In the case of low melting point fibers, these are simply used to maintain the shape of the fabric, and are lost when they are carbonized after baking.If a large amount is mixed in, the product becomes porous, and even though it may be possible to reduce the weight, the water absorption after baking is too high for practical use. Moreover, it is unsuitable for the purpose of molding, and there is a problem in maintaining the shape of the molded product due to large shrinkage during firing. The same can be said of glass fibers since they melt and shrink in size during firing.

To explain the manufacturing method of the present invention, raw clay is pulverized and dried, and a small amount of cut low-melting point fibers and a required amount of high-temperature shape-retaining fibers are added thereto while being defibrated and mixed uniformly with water. The moisture content at this time is 17-23%
It has a softness that makes it easy to mold, and it is put into a vacuum extrusion molding machine. The raw materials kneaded by the vacuum extrusion molding machine are extruded from an arbitrarily shaped mouthpiece of the extrusion molding machine to form a dough molded product.

This extruded dough molded product is sent to a drying device. This drying device dries the product to almost 0% moisture content (in reality, it is about 3% or less), then sends it to a firing furnace and then fires it in a conventional manner to obtain a ceramic product. Since fibrous substances are mixed into the raw materials, the dough retains its shape well, and the shape of the molded dough product does not deform or distort during transportation from the die to the drying device, and it does not suffer from shrinkage during drying. Not only does it not cause any bad phenomena such as cracking or bending, but it also has little heat shrinkage during firing, which eliminates the problems of cracking and deformation that occur in the production of conventional ceramic products. The mixture of fibers makes the ceramic molded product flexible, and even when it is molded into a large thin panel, the panel itself undulates and is flexible and does not easily crack or chip. Because it is mixed in, it is lightweight, so when used as a building material, it is much easier to work with than conventional tiles and bricks, and it is thin at 2-3 mm thick and can be formed into large pieces of 1 m ² or more. Its use is therefore multipurpose. The effect lies in the addition of low-melting point fibers for the purpose of shape-retaining properties of the fabric molded product, and the presence of high-temperature shape-retaining fibers that maintain the shape of the fibers even at high temperatures makes it possible to create a flexible ceramic body. By adding glass fiber, this effect is further improved, breaking the common sense of conventional ceramic molded products, and exhibits outstanding effects not only in production but also as a molded product.

Claims (1)

[Scope of Claims] 1 The viscous substance includes fibers with a low melting point relative to the firing temperature of the clay material, such as asbestos, pulp, and chemical fibers, and fibers with a high melting point relative to the firing temperature, such as calcium silicate fibers. A method for producing a ceramic molded body mixed with fibers, characterized in that the mixed fibers are uniformly shaped, dried, and fired while being defibrated. 2. A method for producing a ceramic molded body by mixing low melting point inorganic fibers such as glass fibers into the mixed fibers according to claim 1.