JPH0211546B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Detailed Description of the Invention] The present invention relates to a method for manufacturing a carbon molded article. Specifically, the present invention relates to a method for producing an ultra-thin plate and a carbon molded product having a thin and complex shape.

Carbon materials exhibit excellent heat resistance without melting or deforming in a non-oxidizing atmosphere. Also, it is a conductor of electricity and heat similar to metal, and generally has great corrosion resistance and is not attacked by various chemicals.

Furthermore, it has a high strength-to-weight ratio as well as a high specific modulus (Young's modulus/density). Materials with such characteristics are useful materials that cannot be found in metals, ceramics, or plastics.

Although there are many types of carbon materials that have been put into practical use, recently, the development of flexible carbon materials has attracted attention, and the use of carbon's physical and chemical properties has begun to gain momentum. In particular, we focus on carbon thin plates and complex molded products that exhibit high mechanical strength under high temperatures, high specific modulus, and stability against corrosive atmospheres.
It is extremely useful for applications in gaskets and gaskets, as electrodes and separators for fuel cells, shielding plates for chemical plants, etc., and as industrial components such as acoustic products that focus on high specific modulus. However, carbon materials have poor malleability and are insoluble and infusible, making it extremely difficult to precisely process them into desired shapes, unlike metals and plastics. Therefore, in the past, complicated and difficult work such as cutting and cutting from a large molded carbon material block was necessary, and it was especially difficult to process thin sheets and mold thin, complex-shaped bodies, and it has not yet been commercialized. It is something that

An object of the present invention is to provide a method for manufacturing extremely thin plate-like and thin-walled complex-shaped bodies, which have conventionally been virtually impossible to manufacture.

In the past, attempts have been made to shape carbonized raw materials such as organic polymer substances and pitzital-based substances by conventional industrial forming methods such as extrusion, injection, and press, and then carbonize them by firing. Or, for thin and complex molded bodies, green molded bodies are used.
It is extremely difficult to maintain its shape when carbonizing it, resulting in deformation or cracking, making it impossible to achieve the purpose.

In view of this situation, the inventors of the present application took advantage of the excellent properties of the carbon material described above to produce the ultra-thin plates and thin complex-shaped objects that can be formed into arbitrary dimensions and shapes with high precision, and basically do not require secondary processing. As a result of intensive research to develop a manufacturing method, we found that materials that undergo solid phase carbonization maintain their shape correctly when fired at high temperatures under controlled conditions. They also discovered that by impregnating and carbonizing these with an organic material with a high amount of carbon residue, a carbon body with even higher density can be obtained while maintaining its shape, leading to the idea of the present invention.

In the method of the present invention, the dehydrogenation reaction is basically carried out by cross-linking organic material fibers or air oxidation that follows solid phase carbonization, or by acid treatment with concentrated sulfuric acid, etc., and the subsequent carbonization path is solid phase carbonization. Using carbonized fiber as a raw material, it can be directly shaped into a designed complex irregular shape by adopting a conventional papermaking process, or it can be processed into a papermaking process.
By applying woven fabric processing and felt processing, paper,
After obtaining cloth or felt, it is shaped into a pre-designed shape by means such as origami processing, gluing, press processing, sewing processing, etc. to obtain a primary molded product of a desired product.

Next, if the organic polymer fiber aggregate used in this primary compact basically undergoes solid-phase carbonization, it can be transferred to the next impregnation treatment process as is, but If insoluble/infusible treatment is required, the crosslinking reaction by air oxidation or the dehydrogenation reaction (referred to as carbon precursor treatment) by acid treatment, which is required at this stage, is sufficiently carried out before primary forming. Body.

The thus obtained primary molded body is impregnated with the liquid organic material that leaves a relatively high carbon residue after firing by dipping or painting, or by applying vacuum or pressure using an autoclave, etc., to thoroughly infiltrate the interior of the impregnated material. Penetrate to. The primary molded body filled with the impregnated material is further subjected to a curing reaction or an insoluble/insoluble material.
A second molded body (referred to as a green molded body) is obtained by performing an infusibility treatment.

The temperature of the secondary compact (green compact) is gradually raised in an inert gas phase atmosphere such as nitrogen gas.
By firing at a temperature of 800° C. or higher and carbonizing, the desired ultra-thin plate and thin-walled carbon molded body having a complex shape are obtained.

Conventionally, organic fibers, short carbon fibers (chopped fibers), powdered carbon, coke powder, etc. have been used as fillers. Attempts have been made to use tar and synthetic resins as binders or matrices, but these fillers have poor ability to maintain the shape of molded products, and the design shape is severely deformed during the firing process, resulting in poor precision. Not only was it not possible to obtain a high quality product, but it was also damaged, making it extremely difficult to achieve the purpose.

Next, the present invention will be specifically explained using Examples, but the present invention is not limited to the following scope.

Example 1 Dissolve 1% by weight of CMC (carboxymethylcellulose) in 500ml of water and adjust the viscosity of the aqueous solution at 20°C.
After adjusting to 120C.PS, commercially available cellulose was added and stirred at high speed to apply high shearing force to obtain a slurry in which the cellulose fibers were swollen and softened and appropriately fibrillated. This slurry was poured into a continuous porous mold with a pre-designed shape as shown in Figure 1, degassed under reduced pressure from the opposite side, and then dried in an air bath at 60°C for 1 hour to form a sheet with a maximum thickness of 2 mm. The shaped paperboard was demolded to obtain a primary molded body. This primary molded body is made of kerimide (Kerimide manufactured by Mitsui Petrochemical Co., Ltd.).
1050, polyimide resin initial condensation polymer) 100g and its solvent NMP (N-methyl pyrrolidone)
Immerse in organic material solution for impregnation dissolved in 200ml,
After sufficient impregnation, excess impregnating liquid is removed, the solvent is evaporated by drying, and the impregnated kerimide is hardened by heat treatment in an air bath at 120°C for 60 minutes to form a secondary molded body. (green molded body)
And so.

Next, the secondary compact is placed in a nitrogen gas stream.
Raise the temperature to 500℃ at 10℃/hour, then increase the temperature to 50℃/hour.
The temperature was raised to 1000°C to carbonize.

The obtained deformed carbon plate has a volume shrinkage rate of 25% bulk specific gravity
The shape designed with 1.45gr/cm ³ was maintained with high precision.

Example 2 Thickness obtained by paper making process based on conventional method
0.3m/m, size 150mmφ paper (manufactured by Toyo Paper Co., Ltd.)
No. 2) was used as the primary molded product, and 100g of chlorinated rubber (CR-150) manufactured by Asahi Denka Kogyo Co., Ltd. was mixed with toluene.
After immersing 100ml in the dissolved organic material liquid for impregnation and thoroughly impregnating it, removing the excess impregnating liquid and drying to volatilize the solvent, place it in an air bath.
Heat treatment was performed at 100°C for 10 hours, then at 150°C for 5 hours, and at 180°C for 3 hours to carry out a crosslinking reaction by air oxidation to obtain a dark brown secondary molded body. Next, this was sandwiched between two graphite plates with smooth surfaces and fired in exactly the same process as in Example 1 to obtain a smooth ultra-thin carbon plate. The obtained carbon plate has a thickness of 0.2 mm, a volume shrinkage rate of 30%, and a bulk specific gravity.
At 1.30gr/cm ³ , the fractured surface had a glass-like appearance and was highly hard and impermeable.

Example 3 A twill fabric with a basis weight of 200 g/m ² obtained by conventional fabric processing using cured novoloid fiber (Kynol fiber manufactured by Gunei Kagaku Co., Ltd.) as a raw material was used as the primary molded product. A mixture of 70% by weight of a furan resin initial condensate (Hitafuran 302 manufactured by Hitachi Chemical Co., Ltd.) and 30% of highly crystalline natural graphite (average particle size 2 μm) was thoroughly kneaded with a roll. The viscosity was adjusted by adding 10 parts by weight of furfural to 100 parts by weight of this composition, and the mixture was immersed in an organic material solution for impregnation with an appropriate amount of curing agent, and after removing the excess impregnating liquid, it was placed in an air bath at 60°C. After processing for 30 minutes, pressurize to 50Kg/cm ² with a pressure press preheated at 100℃ to shape it.
A heat treatment was performed at 150° C. for 3 hours to complete the curing reaction and obtain a second molded product. This was fired under the same conditions as in Example 2 to obtain a smooth ultra-thin carbon plate. The obtained carbon plate had a thickness of 0.15 mm, a bulk specific gravity of 1.55 gr/cm ³ , a glass-like fracture surface, and was impermeable.

Example 4 Paper made from kraft pulp (KP) was press-molded into a corrugated shape, and as shown in Figure 2, a primary molded body with a honeycomb structure was formed by laminating with starch glue, and this was impregnated. A polyimide resin initial condensate (Kelimide 1050, manufactured by Mitsui Petrochemicals, Inc.) was used as an organic material, and carbonized by firing in the same steps as in Example 1 to obtain a thin carbon honeycomb structure.

This carbon honeycomb has a volume shrinkage rate of 25% and has a high bulk specific gravity.
1.50gr/cm ³ and maintained the designed shape with high precision.

Example 5 Commercially available C-PVC Nikatemp T-025 manufactured by Nippon Carbide Industries Co., Ltd. (post-chlorinated PVC, degree of polymerization 650, degree of chlorination 65 ) was melt-spun using a 0.3 mm diameter die and stretched 4 times in air. and obtained filament yarn.
Place this filament yarn in a metal container and heat it to 150°C.
The mixture was heated to obtain a felt-matte primary molded body. This felt mat was immersed in concentrated sulfuric acid.
Carbon precursor treatment was performed by treating at 100° C. for 30 minutes to perform dehydrochloric acid and dehydrogenation reactions. The product thus obtained exhibits a blackish brown color and does not melt and deform again during subsequent carbonization.

This primary molded carbon precursor treated product was washed with water and dried, then immersed in an organic material solution for impregnation, which is made by adding 2 parts by weight of a curing agent to 100 parts by weight of a furan resin initial condensate (Hitafuran 302). Thereafter, the impregnating liquid inside is squeezed out, so that the fiber surface of the primary molded body is uniformly coated with the impregnating liquid. Next, this was sufficiently hardened in an air bath at 100°C, and then fired and carbonized in the same process as in Example 1. In this way, a felt mat-like porous carbon body was obtained. This carbon porous material has a porosity of 80% and a bulk density
It was 0.5 g/cm ³ .

As described above, according to the method for manufacturing a new carbon molded article of the present invention, extremely thin carbon plates and thin carbon bodies with complex shapes, which have been extremely difficult to manufacture in the past, can be easily and economically produced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the papermaking process in Example 1. In the figure, 1 is a slurry, 2 is a continuous porous material molding mold, 3 is a molding mold support frame, and 4 is a decompression chamber. FIG. 2 shows a honeycomb structure in Example 4. In the figure, 5 is a glued part.

Claims (1)

[Scope of Claims] 1. The material is an aggregate of organic polymer fibers that basically have the property of solid-phase carbonization, or an aggregate of synthetic polymer fibers that have the property of undergoing solid-phase carbonization after insoluble and infusible treatment. After shaping into a pre-designed shape through papermaking processing, or obtaining paper, cloth, or felt from each material through papermaking, weaving, or felting, it can be used as it is, or it can be made into origami. The material is shaped into a pre-designed shape by processing, gluing, pressing, sewing, etc., and the resulting material is made of organic polymer fibers that basically have the property of solid phase carbonization. In the case of synthetic polymer fibers, it is used as a base material for impregnation after being treated with a carbon precursor, and then it becomes liquid at room temperature, or it has the property of becoming liquid by using a solvent or heating. , an organic material with a large amount of carbon residue after firing is impregnated, the impregnated excipient is subjected to hardening treatment or insoluble infusibility treatment to obtain a green molded body, and this green molded body is placed in an atmosphere containing an inert gas. A method for producing a carbon molded article, which comprises carbonizing it at a predetermined temperature. 2. The organic polymer fiber, which basically has the property of solid phase carbonization, is selected from the group consisting of pulp and cellulose derivative cotton, novoloid (phenolic) fiber, aramid (aromatic polyamide) fiber, and polyamide-imide fiber. The method for producing a carbon molded article according to claim 1, wherein the carbon molded article is made of a carbon fiber. 3. The synthetic polymer fiber that has the property of undergoing solid phase carbonization after being insoluble and infusible is made of polyacrylonitrile, polyacrylonitrile,
The method for producing a carbon molded article according to claim 1, wherein the fiber is selected from the group consisting of polyvinyl chloride, post-chlorinated polyvinyl chloride, and polyvinyl alcohol. 4. The organic material for impregnation is a thermosetting resin selected from the group consisting of furan resin, phenolic resin, bismaleimide-triazine resin, polyimide resin, amide-imide resin, and aromatic polyamide resin, or an initial condensation product thereof. A method for manufacturing a carbon molded article according to claim 1. 5. The organic material for impregnation is a thermoplastic resin selected from the group consisting of polyvinyl chloride, post-chlorinated polyvinyl chloride, chlorinated rubber, vinylidene chloride, pitch, tar, and lignin. The method for manufacturing the carbon molded article described. 6. The method for producing a carbon molded article according to claim 1, wherein the organic material for impregnation has a viscosity of 50 to 5000 CPS. 7 If the organic material for impregnation is a thermosetting resin,
The method for manufacturing a carbon molded article according to claim 1, which comprises adding a hardening agent during the impregnation treatment. 8 If the organic material for impregnation is a thermoplastic resin,
The method for manufacturing a carbon molded article according to claim 1, which comprises drying the carbon molded article to an absolutely dry state after the impregnation treatment. 9. The method for producing a carbon molded product according to claim 1, wherein the carbonization temperature of the green molded product is 400°C or higher.