JP3241466B2 - Forming method of ceramic fiber molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a molded body of ceramic fiber which is embedded in a base material such as metal or plastics and used for reinforcing the base material.

[0002]

2. Description of the Related Art Composite materials in which a molded body of ceramic fiber is embedded in metal or plastics to reinforce metal or fiber are known. The fiber molded body for this composite material is generally formed by dispersing ceramic whiskers or ceramic short fibers in a solution of water or an organic solvent, adding a binder, and performing suction filtration using a wire mesh, filter cloth, or the like. , Formed by compression molding.

[0003] Since the material used as a mold is a wire mesh or a filter cloth, only a molded article obtained by these methods can be obtained. When a complicated shape is required, a simple shape obtained by the above method is processed into a desired shape by cutting or the like. For this reason, complicated processing is required for detailed processing, and material is wasted due to processing. Since it is extremely difficult to process a composite material using a fiber molded body as a reinforcing material, it is desired that the fiber molded body be formed into a shape close to a required final shape.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a ceramic fiber molded body capable of efficiently forming a ceramic fiber molded body having a complicated shape.

[0005]

According to the present invention, there is provided an upper mold and a lower mold each having a communicating hole having a pore diameter of 25 to 200 μm formed of thermoplastic resin granules and having a thickness of 1 to 10 mm at each portion, Surround the slurry of ceramic fibers with a cylinder surrounding the upper mold and the lower mold,
In the cylinder, the upper mold is forcibly moved to the lower mold to compress the slurry, discharge a part of the water in the slurry to the outside through the communication holes of the upper mold and the lower mold, and form the ceramic fibers. In addition, there is provided a method for forming a ceramic fiber molded body, further comprising the step of vacuum-suctioning from the outside of the lower mold and discharging the water in the slurry to the outside through the communication hole of the lower mold. Another object of the present invention is to form the upper mold and the lower mold with thermoplastic resin and metal and / or ceramic particles.

The thermoplastic resin used for the upper and lower molds includes low-density polyethylene, high-density polyethylene, polypropylene, polystyrene, polymethacrylate, polyethylene-styrene copolymer, cumarone-indene-styrene copolymer and the like. . As metal, stainless steel,
Ceramics such as aluminum and nickel include alumina and mullite. The particle size of these granules is 50
１０００1000 μm is used. These may have different particle sizes.

The ceramic fibers used in the present invention include:
Short fibers such as silicon carbide whiskers, silicon nitride whiskers, potassium titanate whiskers, alumina fibers, and silica-alumina fibers are used. It is desirable that these ceramic whiskers and ceramic short fibers have a desired fiber length by a compression treatment or the like, depending on the required shape and density of the fiber molded body.

The upper mold and the lower mold are prepared by mixing a binder for temporarily maintaining the shape of the granules, for example, a mixed solution of toluene and ethyl alcohol, an aqueous solution of polyvinyl alcohol, and the like. And compression molded in a thermostat at 110 ° C
Heating for 90 minutes or microwave power of 800W for 60 minutes
Heat for a minute. After heating, it is cooled and taken out of the matrix.

[0009] The upper mold thus made is placed below the inside of the cylinder, and the same slurry of ceramic fiber as in the past is poured into the space surrounded by the lower mold and the cylinder, and the upper mold is placed in the cylinder above it. The slurry is compressed by inserting and moving the upper mold toward the lower mold, and the moisture of the slurry is discharged to the outside through the communication holes of the upper mold and the lower mold to form fibers. In this case, the water that has oozed out from the upper surface of the upper die is sucked and discharged, and the water that has oozed out from the lower surface of the lower die is discharged through a pipe or the like. The slurry may be injected from the side of the cylinder between the upper mold and the lower mold.

[0010] In this way, when almost no water comes out of the slurry by compression, the lower mold is connected to a vacuum suction device,
The process is performed until the water content of the slurry is no longer generated by evacuation to form ceramic fibers. Thereafter, the molded body is released from the cylinder, the upper mold, and the lower mold, and dried and fired in the same manner as in the related art to obtain a product.

[0011]

In the present invention, the use of thermoplastic resin particles as the material of the mold is not only because the mold is easy to mold, but also because it has good releasability, but the material of the mold is metal or ceramics. In this case, particles of metal and ceramics are mixed in the molded body of ceramic fiber molded using this mold, and when this molded body is cast into metal, it is contained in the molded body of ceramic fiber. Ceramic particles or metal particles different from the cast metal that are mixed into the cast metal may reduce the physical strength of the obtained composite material or reduce the chemical properties, As a material of the mold, a thermoplastic resin is used. For the above reasons, it is most preferable to use only the thermoplastic resin as the material of the mold, but since the thermoplastic resin is expensive, when forming a composite material using a ceramic fiber molded body as a reinforcing material such as plastic. When mixing of such metals and ceramics is not a problem, the material cost can be reduced by appropriately mixing metal or ceramic particles with thermoplastic resin particles.

The granules used as the material for the upper and lower molds are:
When the particles having a particle diameter of 50 to 1000 μm are used, communication holes having a pore diameter of 25 to 200 μm can be formed in the formed upper mold and lower mold. The hole diameter of the communication holes of these types is 25 to 200 μm.
The reason is that in order to dewater the water of the slurry through the mold at the time of compression molding, if the pore diameter is less than 25 μm, dehydration becomes difficult, and if the compression pressure is increased, the molded body bites into the mold. This is because there is a problem that it is difficult to release the mold. When the pore diameter exceeds 200 μm, the molded body bites into the mold, making it difficult to release the mold, and the irregularities on the surface of the molded body become large and the surface becomes rough. Therefore, the maximum pore diameter is set to 200 μm.

The reason why the thickness of the mold is set to 1 to 10 mm in each part is that if there is a part less than 1 mm, the strength is insufficient and the part is easily broken, and if there is a part exceeding 10 mm, the air flow resistance is reduced. This is because, even if compressed air is ejected from the opposite side of the mold surface during removal of the mold, mold release is deteriorated and removal of the mold becomes difficult.

[0014]

Example 1 Production of Upper Die and Lower Die As shown in FIG. 2, a mother cylinder die 9 is assembled on a mother lower die 7, and a mother middle die 10 is assembled at the center of the mother cylinder die 9. 9 and mother lower mold 7
And a particle size of 400 ± 50μ in a space surrounded by
25 parts by weight of a mixed solution of toluene and ethyl alcohol having a toluene concentration of 14.8 parts by weight as a binder is mixed with 100 parts by weight of polyethylene-styrene copolymer particles (poly powder manufactured by Sanyu Sangyo Co., Ltd.) The granules 11 were put.

The mother die 8 is fitted on the granule 11 with the mother cylinder die 9 and the mother middle die 10, and the mother die 8 is moved toward the mother lower die 7.
The granules 11 were lowered by a pressure of 6 kgf / cm ² and pressed to be formed. Then, it is heated at 110 ° C for 90 minutes in a thermostat,
After allowing to cool, the mold was removed to obtain a lower mold 1 shown in FIG. Similarly, an upper mold 2 shown in FIG. 1 was obtained. The diameters of the communication holes of the lower die 1 and the upper die 2 are relatively uniform, and are 150 to 200 μm.
m. The recesses 12 provided in the upper mold 2 are for forming ribs provided on the inner and outer circumferences so that the mold can withstand compression. Similar ribs are formed by the recesses 12 on the outer circumference of the lower mold 1. It was done.

Production of Ceramic Fiber Molded Body As shown in FIG. 1, the lower mold 1, the cylinder 3 and the middle mold 4 are assembled on the suction device 6, and the lower mold 1, the cylinder 3 and the middle mold are assembled. Alumina fiber having an average fiber length of 100 μm (trade name: Safile manufactured by ICI), colloidal silica (trade name: Snowtex by Nissan Chemical Industry Co., Ltd.), and an organic binder are dispersed in water in a space surrounded by 4. Was poured into the slurry. The upper mold 2 is fitted on the slurry, and the upper mold 2 is
, And water was removed from the slurry through the communication holes of the upper mold 2 and the lower mold 1 to form the slurry until the slurry had a desired density.

After the dewatering, the moisture of the molded body was dewatered by the suction device 6 through the communicating hole of the lower die 1 to complete the molding. After the molding is completed, first, the middle mold 4 and the cylinder 3 are removed, and while air is suctioned by the suction device, pressurized air is blown out from the upper surface of the upper mold 2 toward the molded body through the communication hole of the upper mold 2. , And then the lower mold 1 was removed and removed from the mold. After demolding, the formed ceramic fiber compact was dried and calcined at 105 ° C. in the same manner as in the prior art.

The compact obtained in this way had the same shape over the details of the mold and was homogeneous.
Also, almost no dimensional shrinkage due to drying was observed.

Example 2 The material of the lower mold 1 and the upper mold 2 was 200 μm ± 50 in particle size.
μm coal ash granules (filite) 70 parts by weight and particle size 5
A mixture of 30 parts by weight of polymethacrylate particles having a particle size of 00 μm ± 50 μm (trade name: Parapet manufactured by Kuraray Co., Ltd.) and 30 parts by weight of a mixed solution of toluene and ethyl alcohol containing 15.8 parts by weight of toluene as a binder is used. did.

This was reduced to 30 kgf /
Molding was performed under a pressure of cm ² to obtain a lower mold 1 and an upper mold 2. The holes of the communication holes of this type are well aligned, and
μm range. Using this mold, a molded article of ceramic fiber was formed in the same manner as in Example 1. After molding, 10
After drying in a thermostat at 5 ° C., the molded body was fired together with the mold, and the organic components of the mold were burned to burn off, the mold collapsed, and the mold was released.

The compact obtained in this way had the same shape over the details of the mold and was homogeneous.
Also, almost no dimensional shrinkage due to drying was observed.

[0022]

According to the method of the present invention, a ceramic fiber molded body having a complicated shape can be efficiently molded.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the method of the present invention.

FIG. 2 is an explanatory view of a mold forming method used in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower die 2 Upper die 3 Cylinder 4 Medium size 5 Slurry 6 Suction device 7 Mother lower type 8 Mother upper type 9 Mother cylinder type 10 Mother medium size 11 Granules 12 Concave part

Claims (2)

(57) [Claims] 1. A communicating hole having a pore diameter of 25 to 200 μm formed of thermoplastic resin particles, and having a thickness of 1 to 1 at each part.
A ceramic fiber slurry is surrounded by a 0 mm upper mold and a lower mold, and a cylinder surrounding the upper mold and the lower mold, and the upper mold is forcibly moved to the lower mold in the cylinder to compress the slurry. A part of the water in the slurry is discharged to the outside through the communication holes of the upper mold and the lower mold, and the ceramic fiber is formed. Further, vacuum suction is performed from the outside of the lower mold to communicate the water in the slurry with the lower mold. A method of forming a ceramic fiber molded body, comprising discharging the ceramic fiber molded body through a hole. 2. The method according to claim 1, wherein the upper mold and the lower mold are formed of particles of a thermoplastic resin, metal and / or ceramic.
The method for forming a ceramic fiber formed article according to the above item.