JPS5817151B2 - Manufacturing method for ceramic fiber molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic fiber molded product, and more particularly to a method for manufacturing a three-dimensional molded product using ceramic fibers as fiber bundles.

Conventionally, ceramic fibers are known as kaolin-based high-temperature refractory mineral fibers whose main components are alumina and silica, and because they have extremely superior fire resistance compared to rock wool or glass fibers, they can be used as bulk fibers or as such. It is widely used as heat-insulating, refractory furnace materials, etc.

Among these methods, a particularly smooth molded product is manufactured by directly putting ceramic fibers into water, dispersing them in the water using a crusher, etc. mainly used in the paper industry, and then dispersing them by suction or pressure. The so-called wet papermaking method, which involved molding, was used.

Note that the term "ceramic fiber" as used herein generally refers to cotton-like mineral fibers made by melting a compound mainly composed of alumina and silica in an electric furnace and blowing it with compressed air. be.

However, in the conventional wet papermaking method, since ceramic fibers are defibrated in water, (1) each step of defibrating, mixing, and molding must be performed at the same place;
2) It is extremely difficult to produce large molded products, especially molded products with special shapes.

Moreover, (3) there are restrictions on transportation and storage before the molding process.

and. (4) Substances that are insoluble in water cannot be used as a blend because they are difficult to disperse, and special composite molded products cannot be manufactured.

Furthermore, (5) multilayers called lamination are formed in special composite moldings, so delamination is likely to occur;
There were many drawbacks such as the inability to obtain refractory molded products with high strength or high melting point.

Therefore, the present invention has focused on such drawbacks and has devised ways to solve them.

That is, the first step is to defibrate ceramic fibers in a dry or semi-dry state, and then to form granular or lumpy fiber bundles, and to mix additives such as water, a refractory material, and a binder with the fiber bundles. The present invention provides a method for manufacturing a ceramic fiber molded product, which comprises a second step of molding the ceramic fiber molded product.

In the first step, the ceramic fibers are defibrated in a dry or semi-dry state using a defibrator, and then a sticky binder, such as an organic binder such as CMC or sodium alginate, or By using inorganic materials such as colloidal silica, colloidal alumina, and aluminum phosphate, and mixing them in a kneader or mixer for a certain period of time, we can create granular or lumpy ceramic fiber bundles. It is something to do.

Since the above-mentioned fiber bundle is a mass of ceramic fibers, it contains air, and this air forms an air layer for each fiber bundle, so this air layer provides insulation. effect is brought about.

Further, since the above-mentioned adhesive binder is attached to the surface of the fiber bundle, it is convenient to use this fiber bundle to make a three-dimensional molded article of a certain shape.

Furthermore, another feature of the present invention is that adding and mixing water-insoluble inorganic aggregates can be facilitated by reducing the amount of moisture that is produced during mixing or molding of the compound. Because of this, we manufacture molded products made from specially formulated composite materials that cannot be obtained using conventional methods.
Especially high specific gravity.

The objective is to obtain ceramic fiber molded products with high strength and high temperature fire resistance.

Hereinafter, the present invention will be explained in more detail based on examples and the like.

To defibrate ceramic fibers in a dry or semi-dry state and make them into granular or lumpy fiber bundles as described above, an ordinary dry defibrator is used to unravel the fibers to a constant fiber length. The ceramic fibers can be cut and compressed into granules, or the ceramic fibers can be directly put into a mixer such as a kneader.

It is possible to add a small amount of water, a binder, etc. to this, and then mix and stir.

The fiber bundle obtained here may be an aggregate of ceramic fibers arranged in a substantially uniform direction, or alternatively.

The long and short fibers are entangled, resulting in a state caused by pressure, binders, etc.

The fiber bundle has a granular or lumpy shape with a diameter of about 1 to 50 mm or a flat length, particularly a streamlined to elliptical three-dimensional shape.

Moreover, the bulk specific gravity of ceramic fiber is usually about 0.1.
On the other hand, the bulk specific gravity of the fiber bundle is approximately 0.1 to 0.4 in a dry state, and approximately 0.2 to 0.5 in a state containing some moisture.

In this way, fiber bundles differ from ceramic fibers in that they have a higher bulk specific gravity and less continuous association and bonding, and as a result, workability is improved in manufacturing molded products of a predetermined shape. Are better.

Therefore, a feature and advantage of the present invention is that it has become possible to easily obtain refractory molded products of multiple shapes or large sizes, which could not be obtained by conventional wet papermaking methods using ceramic fibers.

Next, the second step of manufacturing the molded product of the present invention will be explained.

The fiber bundles alone or a mixture of the fiber bundles and ceramic fibers, or a mixture of the fiber bundles and other mineral fibers such as asbestos fibers or glass fibers, are used as aggregates or fillers, and this is coated as a binder. A commonly known binder suitable for ceramic fibers such as rydal silica, colloidal alumina, aluminum phosphate, CMC, and organic silica compounds is used and mixed for a certain period of time in a kneader or mixer.

Furthermore, after selectively blending inorganic substances that can be used as ordinary aggregates, such as fireclay, chamomile powder, and mullite powder, a mixture of these and water is made into any shape by a semi-wet or dry papermaking method. It is used to create three-dimensional molded products.

Furthermore, when a relatively large amount of the binder is used in the first step of producing a fiber bundle, a molded product can be directly produced by simply adding water to the fiber bundle.

At this time, the smaller the amount of water added, the less the fibers, binder, etc. will be washed away during the molding process, and the steps such as dehydration and drying can be simplified.

Example 1 Ceramic fibers with a bulk specific gravity of 0.1 were defibrated and granulated using an experimental kneader to produce ceramic fiber bundles with a particle size of 2 to 101L1L1 with an average bulk specific gravity of 0.2, and added to the fiber bundles. Table 1 below shows the dry bulk specific gravity of the molded product obtained by mixing 20% colloidal silica as an agent in a ratio of 1 part fiber bundle and 3 parts colloidal silica and varying the molding pressure.

Example 2 A ceramic fiber bundle similar to Example 1 was mixed with 20% colloidal silica, 2% CMC, and chamotte powder as additives, and the mixture was pressure-molded at 171 g/cr/l. The dry bulk specific gravity, strength after drying, and strength after firing at 1200° C. of the product are shown in Table 2 below.

As described above, the method of the present invention has many excellent effects, and the molded products obtained by Kempo can be made into large and complex shapes and used as high-strength and high-temperature refractory metallurgical containers. It is extremely useful industrially.

Claims (1)

[Claims] 1 A process of defibrating ceramic fibers in a dry or semi-dry state and producing granular or lumpy fiber bundles using a binder, and a process of producing a three-dimensional molded product using the fiber bundles. A method for manufacturing ceramic fiber molded products.