JP5544526B2 - Carbon material derived from plant biomass and method for producing the material - Google Patents

Description

The present invention relates to a technique for producing a lightweight high-strength carbon material from plant biomass and a lightweight high-strength carbon composite material from plant biomass and a fiber material without using a binder and an impregnating agent. Furthermore, the present invention relates to a sliding, heat-resistant, chemical-resistant, sealing device and system using the material.

Carbon materials or carbon composite materials are widely used in cutting-edge industrial products that require light weight and high strength. They have high thermal conductivity, low coefficient of thermal expansion, self-lubricating property, chemical resistance, heat resistance, for example, brake and clutch device parts for transport aircraft, oil-free sliders, oil-free bearing sliding parts, or It is used for industrial parts such as gaskets and packings for heat or chemical resistance. Carbon fiber reinforced plastic, which is a composite material of carbon fiber and thermosetting resin, is widely used in applications such as structural materials for transportation equipment such as aircraft and automobiles, materials for civil engineering and building structures, and sports equipment materials.

Many of the existing carbon materials or carbon composite materials are made from fossil resources. For example, in carbon fiber reinforced plastic, carbon fiber is made of pitch or acrylic resin, and the base material is made of resin such as unsaturated polyester, phenol, or epoxy.

In modern society, carbon materials or carbon composite materials are consumed and disposed of in large quantities. In addition, a large amount of waste such as mill ends and by-products is produced in the manufacturing process. In particular, in the carbon fiber production process, a large amount of offcuts that have a limited fiber length and cannot be reused are discharged. Effective utilization of those scrap materials that are disposed of in landfills is desired.

Fossil resources are limited, and there is a strong demand from society for industrial products that use sustainable materials to replace fossil resources. Plant biomass such as waste timber, rice straw and rice husks is one of the promising resources, and once in society, a system for recycling and reusing them has been constructed. However, in modern society, the system does not work efficiently in terms of cost or environmental conservation. In particular, rice husks were once carbonized or incinerated by field burning and returned to the soil. However, field burning is a cause of air pollution, so there are many areas that are currently prohibited or restricted. Therefore, a large amount of rice husks that are not used is discharged every year in rural areas where rice is grown. The disposal and effective use of rice husks is a serious problem.

There is a method for producing a light and high-strength carbon material derived from plant biomass by impregnating or mixing a thermosetting resin such as phenol resin with plant biomass or carbonized plant biomass, and further through a carbonization firing step. Proposed. A method of obtaining a hard carbon material by impregnating and curing a phenol resin on wood and woody material and then carbonizing the same is disclosed (Patent Document 1). Further, a thermosetting resin such as phenol resin is applied to a pulp raw material such as bamboo pulp. There has been proposed a method for obtaining a flaky hard carbon material by impregnating and calcining while being pressure-molded in an inert atmosphere (Patent Document 2). In addition, a method for producing a carbon sliding member obtained by mixing and shaping a phenol resin with graphitized powder made from sucrose such as rice bran and subjecting it to a calcination carbonization process has been claimed (Patent Document 3). Furthermore, a method for producing a Si-containing glassy porous carbon sliding member obtained by mixing a pulverized rice husk or pulverized and carbonized rice husk with a phenol resin, followed by curing and carbonization firing processes has been claimed (Patent Document 4).

In this way, sufficient strength cannot be obtained with carbonized calcined products using only plant biomass, and impregnating or mixing raw plant biomass with a thermosetting resin such as phenol to develop the necessary strength. Yes. However, it is pointed out that harmful gases discharged from the thermosetting resin in the manufacturing process are undesirable in the working environment, such as the phenol resin discharging free formalin in the process of carbonization and baking (Patent Document 5). In addition, there is a technical problem that a considerable amount of resin derived from fossil resources must be used while using renewable plant biomass as a raw material. There is an urgent need for a method for producing a lightweight, high-strength carbon material or carbon composite material that is truly environmentally friendly and does not use a resin derived from fossil resources.

JP-A-4-164806 JP 2000-53467 A JP 2003-147163 A JP 2006-16221 A JP 2002-60272 A

Provided are materials having compression resistance, hardness, and injection properties obtained from plant-based biomass, such as a lightweight high-strength carbon material or a lightweight high-strength carbon composite material, and a method for producing the material.

Plant biomass contains lignin as a natural component. When lignin is heated, it has the property of chemically reacting with other components to bond and cure. Therefore, the present inventors have come up with the idea that it is technically possible to produce a lightweight high-strength carbon material only from plant biomass without using a resin derived from fossil resources. In addition, plant-based biomass includes a wide variety of species, but is roughly composed of cellulose, hemicellulose, and inorganic components in addition to lignin. If the above-mentioned problems are solved in rice husks, rice straw, and wood waste, which are representative plant-based biomasses described in detail in the examples, the problems can be solved in other plant-based biomasses.

As a result of the inventor's diligent research, carbon materials that have been heat-compressed and fired under specific conditions using plant-based biomass, particularly crushed rice husks, or heat-injected and fired, are thermosetting resins derived from fossil resources. The special effect that the strength comparable to the high-strength carbon material derived from plant-based biomass using it was developed without using the above. Furthermore, the carbon material which mixed the fiber material, especially the grind | pulverized carbon fiber which has the specific aspect ratio grind | pulverized with the grind | pulverized plant biomass, especially rice husk, was heat-compressed and baked on specific conditions, or was heat-injected and calcined. The inventor has the special effect that the composite material is light in weight while having a low heat shrinkage rate in the manufacturing process and the same strength as compared with the carbon material that does not use carbon fiber. I found it. The inventor only uses mechanical processes such as pulverization, pressurization, and heat treatment, and does not use anything other than agriculture and forestry and industrial waste, has strength characteristics comparable to conventional products, and has excellent environmental resistance. And a method for producing a carbon composite material was completed.

The present invention relates to a method for producing light and high-strength carbon materials and carbon composite materials derived from plant biomass, materials produced by this method, sliding, heat resistance, chemical resistance, sealing devices and systems using the materials. is there.

(1) Plant biomass is pulverized to 1 to 50 μm, heated and compressed to 150 ° C. in a vacuum or an inert atmosphere at a pressure of 20 to 500 MPa, and vacuum or over 150 ° C. to a temperature of 250 to 300 ° C. Compression is stopped in an inert atmosphere and only heating is performed. When the temperature is reached in a vacuum or an inert atmosphere, compression molding is performed at a pressure of 20 to 500 MPa for a fixed time of 1 to 30 minutes, and the molding precursor is vacuumed or inert. A lightweight high-strength carbon material derived from plant biomass, characterized by firing at 500 to 1500 ° C. in an atmosphere, and a method for producing the material.
(2) The fiber material is pulverized to an aspect ratio of 1 to 100, mixed with the pulverized plant biomass, and the mixture is produced into a molding precursor by the method described in (1) above. A light weight high-strength carbon composite material derived from plant biomass characterized by firing at 500 to 1500 ° C. in an active atmosphere and a method for producing the material.
(3) A lightweight high-strength carbon material and a carbon composite material, and a method for producing the material, characterized in that the molding precursor described in (1) and (2) is obtained by injection molding instead of compression molding.

(4) The lightweight high-strength carbon material and carbon composite material according to any one of (1) to (3), wherein the fiber material is carbon fiber, and a method for producing the material.

(5) A sliding device and system comprising the plant biomass-derived lightweight high-strength carbon material and carbon composite material according to any one of (1) to (4).
(6) A heat-resistant apparatus and system equipped with the light-weight high-strength carbon material and carbon composite material derived from the plant biomass according to any one of (1) to (4).
(7) A chemical resistant apparatus and system equipped with the light-weight high-strength carbon material and carbon composite material derived from the plant biomass according to any one of (1) to (4).
(8) A sealing device and system equipped with the light-weight high-strength carbon material and carbon composite material derived from the plant biomass according to any one of (1) to (4).

The present invention relates to a method for producing a lightweight high-strength carbon material only from plant-based biomass without using any binder or impregnating agent, and caking a lightweight high-strength carbon composite material from plant-based biomass and fiber material. It is possible to provide a production method without using any agent or impregnating agent. In other words, industrial parts such as transport aircraft brake and clutch device parts, oil-free sliders, oil-free bearing sliding parts, or heat-resistant or chemical-resistant gaskets and packing, without newly consuming fossil resources. It is possible with the present invention to produce only from agriculture and forestry and industrial waste.

(A) Selection of raw materials Examples of plant-based biomass include wood waste, sawdust, bark, rice straw, rice husk, coffee grounds, okarakasu, rice bran, and pulp waste, and the types of raw materials are not limited. However, rice husk is suitable as a raw material because of the generation amount, the recovery efficiency, the degree of demand for disposal from society, and the excellent strength characteristics of the produced carbon material and carbon composite material. Since rice is a silicic acid plant, rice husk naturally contains about 20% by mass of silicic acid. In the carbon material and carbon composite material derived from rice husks, the carbon component and the SiO ₂ component derived from silicic acid coexist, and a remarkable strength characteristic is expressed.

(B) Pulverization of plant-based biomass The plant-based biomass may be pulverized using a commercially available pulverizer such as a cutter mill, a hammer mill, or a ball mill, and the type of the pulverizer is not limited. However, a planetary ball mill is most preferable from the viewpoint of time efficiency and pulverization. By finely pulverizing, the molded body becomes denser in the heating and compressing step, and the melting / adhesion between the powders becomes stronger, so that high strength is obtained. The particle size of the plant biomass to be pulverized is preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 20 μm or less.

(C) Heat compression molding There is no need to use a special device for heat compression of plant biomass powder, and here, in a cylindrical mold that can obtain a shape that is convenient and suitable for material evaluation after production, A method in which the powder is heated and compressed between two cylindrical rods will be described. In the cylindrical mold, a heater and a thermocouple are installed so that the powder is heated. The pressurization may be performed using a commercially available press device, but it is desirable to insert a heat insulating plate between the mold and the press device.

This will be described with reference to a typical heat compression process diagram shown in FIG. All steps are performed in a vacuum or inert atmosphere. From the viewpoint of apparatus configuration and economy, it is preferable to create an inert atmosphere by flowing nitrogen gas. The powder is heated from room temperature to 150 ° C. under pressure of 20 to 500 MPa. In particular, it is preferable to pressurize at a pressure of 100 MPa. The compression is stopped and only heating is performed until the powder reaches a certain temperature of 250 to 300 ° C. over 150 ° C. A temperature of 250 to 300 ° C. at which the secondary pressurization is performed is defined as a secondary pressurization temperature. When the secondary pressurization temperature is reached, the temperature of the powder is maintained for a certain time and pressurization is performed.

In this heating and compression step, the heating rate of heating is preferably 1 to 20 ° C. per minute, more preferably 3 to 10 ° C. per minute, and particularly preferably 5 ° C. per minute from the viewpoint of work efficiency and molding quality. The secondary pressurizing pressure is preferably 20 to 500 MPa, more preferably 100 to 200 MPa. The secondary pressurization temperature is preferably 270 to 290 ° C. The time for secondary pressurization is preferably 1 to 30 minutes, more preferably 5 to 20 minutes, and particularly preferably 10 minutes. A molding precursor is obtained by a series of heat compression steps.

(D) The molding precursor is baked at 500 to 1500 ° C. in a vacuum or an inert atmosphere after the baking heat compression step. By firing, the molding precursor becomes denser and the strength properties are improved. The molding precursor may be heated to the firing temperature as it is in the heat compression apparatus and fired, or the molding precursor is taken out of the heat compression apparatus and fired in a vacuum or inert atmosphere in another electric furnace or the like. May be. The optimum firing temperature varies depending on the required strength. For example, the compressive fracture strength is preferably in the range of 1000 to 1200 ° C and the hardness in the range of 700 to 900 ° C. The rate of temperature rise until reaching the firing temperature is preferably 5 to 15 ° C per minute. When the molding precursor is heated to the firing temperature, it is preferably held for 1 to 60 minutes.

By passing through the steps (A) to (D), a lightweight high-strength carbon material can be produced from plant biomass without using a binder and an impregnating agent. A lightweight high-strength carbon composite material derived from plant biomass is manufactured through the following manufacturing process.

(E) Selection of fiber material Glass fiber, carbon fiber, petroleum synthetic fiber, or the like can be used for the fiber material. In order to mix with plant biomass powder, pulverized fiber is preferable to long fiber. Carbon fiber scraps that are lightweight and have high strength, and have high adhesiveness with plant-based biomass and are currently discharged as industrial waste are suitable as fiber materials.

(F) Pulverization of fiber material Commercially available pulverizers such as a cutter mill, a hammer mill, and a ball mill can be used for pulverizing the fiber material, and the type of pulverizer is not limited. In particular, a planetary ball mill is suitable for pulverizing carbon fibers. The carbon fiber length can be controlled by the number and size of the planetary ball mill balls, and further by the rotation speed. In order to combine with plant biomass and obtain high strength, the aspect ratio of the carbon fiber is preferably 1 to 100, and more preferably 5 to 10.

(G) Stirring and mixing the plant-based biomass mixed with the plant-based biomass, the fiber material that has been heat-compressed and fired and pulverized, and the plant-based biomass pulverized in the step (B). The mixing amount of the fiber material is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, and particularly preferably 30% by mass with respect to the plant biomass. By passing the mixture through steps (C) and (D), a light and high-strength carbon composite material derived from plant biomass is produced.

The present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

(A) Manufacture of molding precursors Rice husks of Akitakomachi rice produced in Nishikimura, Akita Prefecture (currently Semboku City) in 2005 were used as raw materials. The rice husks were pulverized using a planetary ball mill (P-6 type manufactured by Frichche Japan KK). A 250 mL stainless steel pulverization container was charged with a plurality of stainless steel balls having a diameter of 20.0 mm (total mass: 500 g) and ginger husk, and pulverized for 10 minutes at a rotational speed of 400 rpm. The obtained powder was passed through a sieve having an opening of 100 μm to obtain a starting powder (rice husk powder 1). The rice husk powder 1 was further pulverized for 3 minutes at a rotational speed of 400 rpm using a plurality of stainless steel balls (total mass: 600 g) having a diameter of 4.8 mm (rice husk powder 2). The obtained powder was further pulverized for 3 minutes at a rotational speed of 400 rpm using a plurality of stainless steel balls (total mass: 300 g) having a diameter of 1.6 mm (rice husk powder 3).

The average particle size of the powder was measured using a laser diffraction particle size distribution measuring device (SALD-200V type manufactured by Shimadzu Corporation). Table 1 shows the average particle diameter of the produced rice husk powder. Each value is the average of three measurements.

A molding precursor was produced by heat compression molding using rice husk powder 3 having an average particle size of 15.3 μm. 0.70 g of dried rice husk powder 3 was weighed, and nitrogen gas was flowed in an amount of 1 L / min between two cylindrical rods having a diameter of 9.98 mm in a cylindrical mold having a diameter of 10.00 mm. However, it was subjected to heat compression molding. The heating and compression process was performed under the production conditions shown in FIG. 1, but the secondary pressurizing pressure was fixed at 100 MPa, the secondary pressurizing temperature was varied between 250-400 ° C. The state of production of the body was observed. Table 2 shows the secondary pressurization temperature and the pressure production state findings.

When the secondary pressurization temperature was 200 ° C., since the heat-compressed powder had fluidity, the fluidized powder leaked from the gap between the cylindrical mold and the cylindrical rod, and pressurization was impossible. At 250 ° C., the fluidized powder leaked considerably less, but cracks were observed in the molding precursor. In the case of 280 ° C., there was no leakage, no cracks, and a good molding precursor was obtained. In the case of 300 ° C. Although there was no leakage, cracks were observed. In the case of 400 ° C., there was no leakage, but it was crushed. Thus, the best molding precursor can be produced by setting the secondary pressurization temperature to 280 ° C.

(B) Production of lightweight high-strength carbon material from different types of plant biomass In addition to rice husk powder 3 described in Example 1, rice bran from Akitakomachi produced in Yokote City, Akita Prefecture in 2005, and Yurihonjo, Spring Akita Prefecture in 2005 City-produced cedar waste was pulverized by the same method as the method for producing rice husk powder 3 described in Example 1. Table 3 shows the average particle size of rice husk powder 3, wood waste powder and rice straw powder. Each is an average of three measurements. The temperature was set to 280 ° C., and other conditions were set to the conditions shown in Example 1, and the rice husk powder 3, wood waste powder, and rice straw powder were heated and compressed. After the temperature of these molding precursors reached 500 ° C., 500 ° C. was maintained for 5 minutes in the same heating and compression apparatus, and firing was also performed.

Table 4 shows the mass, diameter, thickness, and bulk density of a disc-shaped carbon material fired at 500 ° C. produced from rice husk powder 3, wood waste powder, and rice straw powder. The bulk density is a value obtained by dividing mass by volume (diameter ² × π × thickness ÷ 4). Each value is a single measurement. Although the mass, diameter, thickness, and bulk density of the carbon material produced by the starting material differed, all the molding conditions were very good.

(C) Production of lightweight high-strength carbon material from rice husk powder having different average particle diameters Molded by the method described in Example 1 using three kinds of rice husk powders 1, 2, and 3 shown in Table 1 as starting materials A precursor was produced. The secondary pressurization temperature was set at 280 ° C. Moreover, the molded object was heated in the heating compression apparatus to 500 degreeC. And after reaching 500 ° C., it was naturally cooled to room temperature. The molding precursor naturally cooled to room temperature was heated to 1200 ° C. at a temperature rising rate of 10 ° C./min in a flow of nitrogen gas at 1 L / min in another electric furnace and fired. After holding at 1200 ° C. for 60 minutes, it was naturally cooled to room temperature to produce a lightweight high-strength carbon material derived from a disk-shaped rice husk.

The compressive strength of the carbon material produced using a precision universal testing machine (EZGraph 10 kN manufactured by Shimadzu Corporation) was evaluated. The material was placed on a test table and a test force was applied in the thickness direction. The compression load speed was 1 mm per minute, and the measured maximum compression pressure was defined as the compression strength.

Table 5 shows the mass, diameter, thickness, bulk density, and compressive strength of the disc-shaped carbon material fired at 1200 ° C. produced from rice husk powder 1, 2, and 3. Each value is an average of 5 measurements. When the average particle diameter of the rice husk powder as the starting material was reduced, the bulk density of the produced carbon material was increased, and a high compressive strength was obtained.

(D) Optimization of firing temperature for production of lightweight high-strength carbon material Starting from rice husk powder 3, the secondary pressurization temperature is set to 280 ° C. and the secondary pressurization pressure is set to 100 MPa. It heated in the heat compression apparatus to 500 degreeC. 500 degreeC was hold | maintained for 5 minutes and the 500 degreeC calcination carbon material was manufactured. On the other hand, after reaching 500 ° C., it was naturally cooled to room temperature to produce a molding precursor. These molding precursors are heated to 800, 1000, 1200, 1400 ° C. at a rate of temperature increase of 10 ° C. per minute in a 1 L / min nitrogen gas flow in another electric furnace, and the temperature is maintained for 60 minutes. Baked. And it was made to cool naturally to room temperature, and manufactured the disk-shaped carbon material.

Table 6 shows the mass, diameter, thickness, bulk density, and compressive strength of the material produced at different firing temperatures. Each value is the average of 5 measurements. The compressive strength was measured by the method described in Example 3. The result of the firing temperature of 1200 ° C. is the same as the result of rice husk powder 3 shown in Table 5. As the firing temperature increased, the compressive strength increased. The highest compressive strength was obtained at 1200 ° C, and the compressive strength decreased conversely when the temperature was further increased to 1400 ° C. Accordingly, it is confirmed that 1200 ° C. is the optimum firing temperature that gives the highest compressive strength.

(E) Production of lightweight high-strength carbon composite material from rice husk powder and pulverized carbon fiber A PAN (polyacrylonitrile) -based carbon fiber end material (length: about 35 mm, diameter: 10 μm) was pulverized by a planetary ball mill. Place a plurality of stainless steel balls with a diameter of 20.0 mm (total mass: 500 g) and about 3 g of carbon fiber in a 250 mL stainless steel crushing container, and the planets described above for 15 minutes at a rotational speed of 400 rpm. It grind | pulverized using the type | mold ball mill. The pulverized carbon fiber was observed using an optical video microscope (VH-5000 type manufactured by Keyence Corporation). The length of the carbon fibers was distributed in a range of 10 to 300 μm, and in particular, 50 to 100 μm, that is, pulverized carbon fibers having an aspect ratio of 5 to 10 accounted for about 50%.

Carbon fiber pulverized with respect to rice husk powder 3 shown in Table 1 is mixed at 0 to 50% by mass, and a carbon composite material fired at 500 ° C. in the same method as the heat compression and firing method described in Example 2 is used. Manufactured. Table 7 shows the mass, diameter, thickness, bulk density, and compressive strength of the disc-shaped rice husk-derived carbon composite materials fired at 500 ° C. with different mixing amounts of pulverized carbon fibers. Each value is the average of 4 measurements. The compressive strength was measured by the method described in Example 3. As the crushed carbon fiber mixing amount increases, the diameter of the carbon composite material produced is equal to 10 mm, which is the diameter of the molding die. This result means that the composite with the pulverized carbon fiber reduced the heat shrinkage rate. Moreover, when the pulverized carbon fiber mixing amount was 30% by mass, the bulk density and the compressive strength showed the highest values. The bulk density increased from 1.26 to 1.37 g / cm ³ compared with the case of not mixing (0% by mass), which was slightly increased in weight, but the compressive strength was doubled. On the contrary, the bulk density and the compressive strength decreased as the amount of pulverized carbon fiber increased by 50% by mass.

The bulk density and compressive strength of the carbon material obtained by firing rice husk powder 3 shown in Table 5 at 1200 ° C. are 1.48 g / cm ³ and 55.7 MPa, respectively. By mixing 30% by mass of pulverized carbon fiber, a compressive strength higher than that of the rice husk-derived carbon material fired at 1200 ° C. was exhibited even at a firing temperature of 500 ° C. Furthermore, the bulk density was 1.37 g / cm ³ , which was about 7% by weight lighter than the rice husk-derived carbon material fired at 1200 ° C.

(F) Heat resistance of rice husk-derived lightweight high-strength carbon material and carbon composite material According to the methods described in Examples 3 and 5, rice husk powder 3 and a mixture of rice husk powder 3 and pulverized carbon fiber (carbon fiber mixing amount: 30 mass%) as a starting material, the heat resistance of carbon materials and carbon composite materials fired at 500 ° C. for 5 minutes and 1200 ° C. for 60 minutes was evaluated. Using a thermogravimetric analyzer (TGA-51, manufactured by Shimadzu Corporation), the carbon material or carbon composite material was heated at a rate of temperature increase of 10 ° C. per minute while flowing 200 mL of air per minute. The mass reduction behavior was observed.

Table 8 shows the mass of the material at 250 to 450 ° C. with the mass at 100 ° C. being 100 in the thermogravimetric analysis process. The mass loss of carbon materials and composite carbon materials fired at 500 ° C. and 1200 ° C. is almost not until 300 ° C. In the carbon material and composite carbon material fired at 500 ° C., a loss exceeding 1% by mass was observed from around 350 ° C. The carbon material and composite carbon material fired at 1200 ° C. did not exceed 1% in mass loss even at 400 ° C. The composite carbon material fired at 1200 ° C. had a mass loss of 1% even at 450 ° C., and extremely high heat resistance was achieved.

(G) Chemical resistance of rice husk-derived lightweight high-strength carbon material and carbon composite material According to the method described in Examples 3 and 5, rice husk powder 3 and rice husk powder 3 and a mixture of pulverized carbon fibers (carbon fiber mixing amount) : 30 mass%) as a starting material, the chemical resistance of carbon materials and carbon composite materials fired at 1200 ° C. for 60 minutes was evaluated. The material was immersed in a 0.1 mol / L hydrochloric acid aqueous solution (pH: 1), a 0.1 mol / L sodium hydroxide aqueous solution (pH: 13), and a toluene solvent having a mass of 100 times at 25 ° C. for 7 days. .

The state after the material was immersed in the chemical, washed and dried was observed, but no change was observed in all. Table 9 shows the mass change after the material is immersed in the chemical, washed and dried. The mass before immersion is defined as 100. The mass loss due to immersion was less than 0.5% for the 1200 ° C. fired carbon material and less than 2.0% for the 1200 ° C. fired composite carbon material. Therefore, the high chemical resistance of the light and high strength carbon material and carbon composite material derived from rice husk was confirmed.

(H) Hardness of plant biomass-derived lightweight high-strength carbon material and carbon composite material 3 As a starting material, the secondary pressurization temperature is set to 280 ° C., the secondary pressurization pressure is set to 100 MPa, and the molded body Was heated to 500 ° C. in a heat compression apparatus. 500 degreeC was hold | maintained for 5 minutes and the 500 degreeC calcination carbon material was manufactured. On the other hand, after reaching 500 ° C., it was naturally cooled to room temperature to produce a molding precursor. These molding precursors are heated to 800, 1000, 1200, 1400 ° C. at a rate of temperature increase of 10 ° C. per minute in a 1 L / min nitrogen gas flow in another electric furnace, and the temperature is maintained for 60 minutes. Baked. And it was made to cool naturally to room temperature, and manufactured the disk-shaped carbon material. Vickers hardness was measured using a micro hardness tester (Fischer Instruments Co., Ltd. H100C / XYp type). The Vickers hardness is a scale representing the hardness of the most widely used industrial material, and is a kind of indentation hardness measured using a square pyramid diamond as an indenter.

Table 10 shows the mass, diameter, thickness, bulk density, and Vickers hardness of the rice husk-derived carbon material fired at different temperatures. Mass, diameter, thickness, and bulk density are values of one sample, and Vickers hardness is an average value of six measurement points on the sample surface. For the case where the firing temperature was 800 and 1000 ° C., a carbon material with a secondary pressurizing pressure of 200 MPa was also produced and evaluated. When the secondary pressurizing pressure was 100 MPa, the Vickers hardness reached its maximum value when the firing temperature was 800 ° C., and conversely decreased when the firing temperature was higher than that. Further, when the secondary pressurizing pressure was increased from 100 to 200 MPa at the highest firing temperature of 800 ° C., the Vickers hardness was further increased to 476 MPa.

Using a mixture of rice husk powder 3 and pulverized carbon fiber as a starting material, the secondary pressurization temperature was set to 280 ° C., the secondary pressurization pressure was set to 100 MPa, and the compact was heated to 500 ° C. in a heat compression apparatus. 500 degreeC was hold | maintained for 5 minutes and the 500 degreeC baking composite carbon material was manufactured. Table 11 shows the mass, diameter, thickness, bulk density, and Vickers hardness of 500 ° C. calcined rice husk-derived composite carbon materials with different pulverized carbon fiber mixing amounts. Mass, diameter, thickness, and bulk density are values of one sample, and Vickers hardness is an average value of six measurement points on the sample surface. As the pulverized carbon mixing amount increased, the Vickers hardness decreased. When the pulverized carbon fiber mixing amount is increased, the thermal shrinkage rate is reduced due to the pulverized carbon fibers, and the composite carbon material is not densified. However, when the secondary pressurizing pressure was increased to 200 MPa, the composite carbon material was densified, and the Vickers hardness was improved to about 146 times as compared with the case of 100 MPa.

A lightweight high-strength carbon material manufactured from rice husk powder 3 was used as a sliding member for a simple slider, resulting in an excellent sliding member due to its high hardness.

When it was used for a simple gasket member by the lightweight high-strength carbon material produced from the rice husk powder 3 and the pulverized carbon fiber, it became an excellent seal member due to the high compressive strength.

Using 0.70 g of dried rice husk powder with a cylindrical mold having a diameter of 10.00 mm and two cylindrical rods having a diameter of 9.80 mm and a diameter of 9.98 mm, nitrogen gas was allowed to flow in an amount of 1 L / min. In the manufacturing process shown in FIG. The secondary pressurization pressure in that case was 300 MPa, and the secondary pressurization temperature was 260 degreeC. It was confirmed that the rice husk powder was discharged in a viscous form from the outer surface of the cylindrical rod having a diameter of 9.80 mm to be pressed, and injection molding was established.

Explanatory drawing which shows the heating compression process of raw material powder.

Claims (9)

Plant biomass is pulverized to 1 to 50 μm, heated and compressed to 150 ° C. in a vacuum or inert atmosphere at a pressure of 20 to 500 MPa, and stopped in vacuum or inert atmosphere above 150 ° C. to 280 ° C. When the temperature reaches 280 ° C. in a vacuum or an inert atmosphere, compression molding is performed at a pressure of 20 to 500 MPa for a fixed time of 1 to 30 minutes, and the molding precursor is 500 to 1500 ° C. in a vacuum or an inert atmosphere. A method for producing a light-weight high-strength carbon material derived from plant biomass, characterized by firing at a low temperature. The fiber material is pulverized to an aspect ratio of 1 to 100, mixed with the pulverized plant biomass, and the mixture is formed into a molding precursor by the method described in claim 1, in a vacuum or an inert atmosphere. A method for producing a lightweight high-strength carbon composite material derived from plant biomass, characterized by firing at 500 to 1500 ° C. A method for producing a light-weight high-strength carbon material or a light-weight high-strength carbon composite material derived from plant biomass, wherein the molding precursor according to claim 1 or 2 is obtained not by compression molding but by injection molding. A method for producing a lightweight high-strength carbon composite material derived from plant biomass, wherein the fiber material according to claim 2 is carbon fiber. Lightweight high strength carbon material or lightweight high strength carbon composite material derived from a plant biomass, characterized in that it is made in any of the methods described in claims 1-4. A sliding device comprising the plant biomass-derived light-weight high-strength carbon material or light-weight high-strength carbon composite material according to claim 5 . A heat-resistant device comprising the light-weight high-strength carbon material or light-weight high-strength carbon composite material derived from plant biomass according to claim 5 . A chemical-resistant apparatus equipped with the light and high-strength carbon material or light and high-strength carbon composite material derived from plant biomass according to claim 5 . A sealing device, comprising the light-weight high-strength carbon material or light-weight high-strength carbon composite material derived from plant biomass according to claim 5 .