JPH0670554B2 - Shelf board for firing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of a baking shelf made of SiC which is used when baking a ceramic product at 800 to 1400 ° C.

(Prior art) When firing ceramic products at 800-1400 ℃, 80
The surface of a baking shelf made of SiC consisting of ~ 92% SiC and 8-20% SiO ₂ or Si ₃ N ₄ is coated with a fire resistant coating to prevent the product from sticking to the shelf. The coated one is used.

Alumina, mullite, or a mixture thereof is mainly used as such a fireproof coating material.
If you use a covering material that has poor adhesion to the made shelf board, it easily becomes dust, and there is a problem that the work place becomes dirty and the working environment deteriorates, and when the product is removed from the shelf board, it easily adheres to the product and peels off, There is a problem that it is necessary to repaint the shelf board with coating material, and if the coating material that has good adhesion to the shelf board is used, it cannot be applied thickly, so peeling off when baking heavy objects It was easy to do and had the drawback of having to be reapplied many times.

(Problems to be Solved by the Invention) The present invention solves the conventional problems as described above, can prevent sticking to the ceramic product SiC shelf plate, and is less likely to generate dust, and the shelf plate The present invention has been completed in order to provide a baking shelf that can save the trouble of forming a thick layer of coating material on the surface and re-coating.

(Means for Solving the Problem) The above-mentioned problem is that the surface of the SiC shelf plate has 15 to 35 parts of aluminum hydroxide and 30 to 50 parts of fused alumina for 100 parts of wax stone.
Layer mixed with 1 part, mullite 90-97 parts clay 3-10
This can be solved by a baking shelf characterized in that a second layer in which parts are mixed is formed by coating.

As described above, the present invention is one in which the first layer and the second layer are formed in two layers on the surfaces of both sides or one side of the SiC shelf board,
With such a two-layer structure, it is possible to improve the adhesion to the shelf plate and increase the film thickness.

The first layer is mainly composed of pyrophyllite, which provides heat resistance and adhesion to a SiC shelf plate. Aluminum hydroxide mixed at a ratio of 15 to 35 parts to 100 parts of pyrophyllite and fused alumina at a ratio of 30 to 50 parts both improve the adhesion to the second layer of mullite. It is an ingredient for making. Here, if the mixing ratio of aluminum hydroxide and fused alumina is more than this range, the adhesiveness with the second layer is deteriorated and peeling easily occurs. On the contrary, if the amount is less than this range, a problem occurs in heat resistance.

In order to coat the surface of the shelf with such a first layer, an organic binder such as methyl cellulose carboxylate and water are added to each of the above components and kneaded, and the surface of the shelf is coated with about 2 to 3 mm. It may be applied to a thickness. Then, after drying the first layer, the second layer is applied.

The second layer contains mullite as a main component, and the mullite preferably has a particle size of 44 μm or less in order to reduce surface irregularities. However, since it is difficult to apply with mullite alone, 3 to 10 parts of clay is added.
If the amount of clay is less than this range, it cannot be applied thickly. On the contrary, if the amount is too large, the silica content will elute and the product will easily stick to the product. An organic binder such as methyl cellulose carboxylate and water are added to these components and kneaded,
Apply to the surface of the layer to a thickness of about 0.3 to 1.0 mm. Then, the surface of the product is to be polished according to the accuracy of the product to be fired.

(Operation) The baking shelf of the present invention configured in this way is composed mainly of wax stone having excellent adhesion to SiC on the surface of the shelf made of SiC, and also having excellent adhesiveness to mullite. A first layer containing aluminum hydroxide and fused alumina, and a second layer made of mullite and clay, which is hard to stick to a ceramic product, is formed on the surface of the first layer. For this reason, it is possible to completely prevent the adhesion of the ceramic product during firing, and to make the first and second layers SiC
It has good adhesiveness to the shelf board and can be applied thickly to the surface of the shelf board.

Therefore, the baking shelf of the present invention is less likely to generate dust and is less likely to be peeled off even when a heavy object such as an insulator is baked, and the number of times of re-application can be greatly reduced as compared with the conventional case.

Next, examples of the present invention will be described.

(Example) 100 parts of wax stone, 33.3 parts of aluminum hydroxide, 50.0 parts of fused alumina, 6.0 parts of methyl cellulose carboxylate, and 100 parts of water are uniformly stirred for about 15 minutes, and a SiC shelf board ( 750 × 635 mm) on both sides to have a thickness of 2 to 3 mm and dried to form a first layer.

Next, 97 parts of mullite having a particle size of 44 μm or less, 3 parts of clay, and 1 part of methyl cellulose carboxylate were stirred with 50 parts of water, and applied on the surface of the first layer to a thickness of about 0.5 mm to form the second layer. And Therefore, the total thickness of the first layer and the second layer could be increased by about 2 to 3.3 mm as compared with the conventional product.

The ceramic porcelain insulator, which is a ceramic product, is placed on the thus obtained baking shelf of the present invention, and the load applied to the shelf is applied.
Calcination was performed at 1300 ° C. at 0.25 kg / cm ² . As a result,
When the baking shelf of the present invention is used, the amount of dust generated is 0.5 g / cm ² , which is 5.8 g / cm ² less than before, and the time required to clean one baking shelf is 5 I was able to reduce it by about 10 seconds. Furthermore, repair of the peeled portion could be performed very easily.

(Comparative Example) On the other hand, a SiC shelf plate coated with only the second layer on the surface can be applied only to a thickness of about 0.3 to 1.0 mm, and cleaning and repainting of the shelf plate are possible. The number of times increased, and the amount of dust generated increased accordingly.

Further, in the case where only the first layer was coated on the surface of the shelf plate made of SiC, the number of times the cleaning and repainting of the shelf plate were increased due to sticking with the product, and the amount of dust generation was also increased.

Further, when the surface of the shelf plate made of SiC was coated with the mixture of the components of the first layer and the components of the second layer, the product adhered to the product.

(Effects of the Invention) As described in detail above, the baking shelf of the present invention is made of Si.
By forming the first layer and the second layer as described above on the surface of the shelf made of C, it is possible to prevent the ceramic product and the shelf made of SiC from sticking to each other, and also to remove the coating layer. It has many advantages such as prevention, dust generation can be reduced and the working environment can be improved, and it is possible to reduce the number of steps to form a thick coating layer on the surface of the shelf board and to apply it again. Is something that can be done.

Therefore, the present invention has an extremely great contribution to the development of industry as a baking shelf that eliminates the conventional problems.

Claims (1)

[Claims] 1. A first layer in which 15 to 35 parts of aluminum hydroxide and 30 to 50 parts of fused alumina are mixed with 100 parts of pyrophyllite on a surface of a shelf made of SiC, and 90 to 97 parts of mullite. A shelf board for firing, characterized by being coated with a second layer containing 3 to 10 parts of clay.