JPH0135766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a hard carbonaceous plate. Specifically, the present invention relates to a method for easily manufacturing a hard carbonaceous plate having a low air permeability, high strength, high elasticity, isotropy, and a uniform thickness ranging from several tens of micrometers to several mm.

Such carbon plates can be applied to packings and gaskets, and can be used to reduce the weight of electrodes and shielding plates for chemical plants, etc., and although attempts have been made to manufacture them using various methods, the methods described above have not yet been achieved. A hard carbonaceous plate that satisfies the conditions has not been obtained. For example, impermeable graphite is usually made by impregnating a carbon material with phenolic resin or furan resin and then hardening it, or by impregnating it and hardening it and then re-firing it, or by impregnating it and hardening it and then re-firing it.
Although it is made by repeatedly curing and firing, it has a low air permeability (K = 10 ^-8 cm ² /s), a strength more than twice that of the base material, and excellent corrosion resistance, but the manufacturing process is complicated. Not only that, but due to the manufacturing method, it is limited to thick products, and it has the disadvantage that it is almost impossible to reduce the weight. That is, carbon materials are usually manufactured in the form of blocks, and cutting them into thin plates is necessary, but it is extremely difficult to cut them to a thickness of 1 mm or less, and the thickness is at most several mm. Even if it were possible to cut the material, it would be extremely difficult to process it after impregnating it with resin to prevent cracks, and even if it were to be cut into thin sheets after being made impermeable, the hardness of the carbon material has increased dramatically, making it expensive. Since a cutter must be used and advanced cutting techniques are required, even if thin plates could be manufactured in this way, the cost would be extremely high. An example of successful thinning of carbon products is sheet-shaped flexible graphite.
This sheet-like graphite is made by acid-treating natural graphite, heating it to form expanded graphite, and then rolling it. It can be made as thin as several tens of microns, making it lightweight, and has an air permeability of 2 x 10 ^- It is small at ⁴ cm/s. However, the bending strength is equal to zero and it has the disadvantage that it can only be used at locations where no bending stress acts. Furthermore, since a large amount of strong acid is used in the manufacturing process, sufficient attention must be paid to the corrosion resistance of the equipment, wastewater treatment, etc., which inevitably leads to higher costs. on the other hand,
It is as impermeable as glass (K=10 ^-10 ~
10 ^-12 cm ² /s), has extremely high mechanical strength, isotropy, and has a very small surface area. This glassy carbon is made from thermosetting synthetic resins such as furan resins and phenolic resins, and by adding an appropriate curing agent to this, it is cured for a long period of 1 to 6 weeks at room temperature or a slightly higher temperature. It is obtained by hardening the material over a period of time, and then carbonizing it at a slow temperature increase rate to prevent cracking due to the protrusion of volatile components generated by thermal decomposition. As described above, the conventional production of glassy carbon not only takes a long time to carbonize, but also makes it extremely difficult to obtain thin plates from the production process, and the hardness is extremely high, making it impossible to cut thin plates from blocks. This is more difficult than with permeated graphite.

Therefore, an object of the present invention is to extremely easily produce a uniform hard carbon thin plate having a low air permeability, high strength, high elasticity, and high hardness, and is isotropic and has a thickness of several tens of microns to several mm. It is an object of the present invention to provide a method of manufacturing at low cost without secondary processing.

In order to achieve this objective, the inventors of the present application took into account the above circumstances, and achieved a final plate state with high precision, which has excellent formability at room temperature and does not require difficult pre-treatment during carbonization. We are conducting research to obtain a molding composition that can produce high-density, high-strength, hard carbonaceous plates that do not require secondary processing. A mixture of homogeneously dispersed polymer resin binder and a polymer resin binder, which has been subjected to a high degree of mechanical energy, has a high degree of moldability at room temperature, unlike the properties exhibited by the first plain material. It was discovered that the carbon powder made infusible by oxidation alone and fired is homogeneous, has high mechanical strength, and can achieve the desired dimensional accuracy.Based on this knowledge, as a result of further intensive research, the carbon fine powder of the present invention was developed. , as a binder, a thermosetting resin monomer, prepolymer, or low polymer that exhibits a high carbon residue yield after sintering and is relatively easily polymerizable.
A species or a mixture of two or more species is uniformly dispersed, and mechanical energy is applied to induce a mechanochemical phenomenon to uniformly and physicochemically solidify the binder to the surface of the primary particles of the fine powder. A paste-like composition for molding is obtained, which is formed into a film or sheet using a casting method or a coating method, and after being subjected to an infusibility treatment, in an inert gas atmosphere. We have now invented a method for manufacturing hard carbonaceous plates that essentially does not require secondary processing, which is characterized by firing.

That is, one or more types of thermosetting resin monomers, prepolymers, and low polymers that can be relatively easily polycondensed and that exhibit a high carbonaceous residue yield after firing are selected as the binder; In addition, fine-grained carbon as an aggregate, i.e., graphite with an average particle size of 100 μm or less,
Carbon black, coke powder, etc. are added, and in the coexistence of fine carbon powder, a polymerization catalyst for a binder is added as necessary, and a high degree of mechanical energy is applied to distort the crystal lattice caused by structural destruction of the aggregate powder. , disturbance and amorphization, generation of lattice defects and active sites on the surface, generation of local high temperature and high pressure conditions,
Utilizing the effect of exoelectrons and the generation of fresh cross sections with a high potential field, a highly fluid pasty composition containing finely dispersed particles in which the above-mentioned binder substance is highly bonded physicochemically through mechanochemical phenomena is produced. This is a composition for producing hard carbonaceous plates.

In the present invention, as described above, a paste-like composition with high fluidity is used as a molding composition, so the film or sheet obtained by molding has a highly precise thickness and a smooth surface. It can be freely selected from plain to satin or patterned, and depending on the molding method, it can be mass-produced and manufactured at low cost.

Examples of the monomer, prepolymer, or low polymer of the thermosetting resin used in the present invention include divinylbenzene, methyl vinyl ketone, phenol resin, furan resin, bismaleimide triazine resin, diphenyl oxide, epoxy resin, and unsaturated polyester resin. However, furan resin, phenol resin, and bismaleimide triazine resin are suitable for ease of handling and moldability.

As the fine carbon powder, one or more of natural scale graphite, natural earthy graphite, artificial graphite, carbon black for rubber, carbon black for colors, lamp black, coke powder, etc. with an average particle size of 100 μm or less is used. If the powder has an average particle size of 100 μm or more, the surface of the film or sheet will be rough during molding, and the mechanical strength after firing will be low, making it impossible to obtain a good hard carbonaceous plate. The blending amount of carbon fine powder is appropriately selected in the range of 5 to 70 weight percent based on the blended composition, but if the blending amount is less than 5 weight percent, the binder will physicochemically change to carbon fine powder due to mechanochemical phenomenon. The absolute amount of finely dispersed particles that are highly bonded to the carbon fibers is insufficient, making it impossible to obtain a good hard carbonaceous plate, and if the blending amount exceeds 70% by weight, the paste composition will have poor fluidity and will not be able to be molded well. This is not preferable because it is difficult and at the same time it becomes difficult to perform a sufficient degassing operation.

In the method of the present invention, first, 30 to 95 percent by weight of a thermosetting resin monomer, prepolymer or low polymer, and 70 to 5 percent by weight of fine carbon powder are mixed uniformly in a blender as necessary. Using a kneading machine with a strong shearing force, such as a mixing roll, a Banbury mixer, or a rotary ball mill, a paste containing fine particles in which the binder substance is highly bonded physicochemically is produced by a mechanochemical phenomenon. . At this time, if necessary, a polymerization catalyst or lignin, violanthrone, naphtha decomposition pitch, or vinyl chloride pitch, which can be mixed with the binder component and exhibit a high carbon residue yield after calcination, may be added to the binder. Even if the ingredients are solid at room temperature or liquid at room temperature, they may be heated during kneading or a small amount of solvent or plasticizer may be added to improve fluidity and kneadability with fine carbon powder. It's okay.
The viscosity of the molding paste is 100℃, depending on the molding method.
100 poise or less at 100°C, preferably 20 poise or less at 100℃, but the viscosity can be adjusted by adjusting the type and amount of binder, the type and amount of polymerization catalyst, the type of fine carbon powder, the particle size, the amount of compounding, Since this can be easily carried out by adjusting the kneading temperature, kneading time, and amount of solvent or plasticizer added, it is possible to obtain pastes with various viscosities depending on the molding method.

Next, the molding paste composition is shaped into a film or sheet with a thickness of several tens of microns to several millimeters using a casting method or a coating method. At this time, a polymerization catalyst may be added to the paste composition in advance in order to promote curing of the thermosetting resin after shaping. In the casting method, a paste composition is cast onto a flat plate to form a film or sheet. In the coating method, a paste composition is applied onto a flat plate using a spray, a doctor knife, a reverse roll, an air knife, or the like. To uniformly cast or coat,
In order to lower the viscosity of the paste-like composition, it is also good to heat the composition during coating. The cast or coated composition is left at room temperature or heated to volatilize the optionally added solvent or plasticizer to cure the thermosetting resin. then 50~
Put it in a heating oven at 300℃ and perform infusibility treatment.
Firing is performed by gradually raising the temperature in an inert atmosphere. The firing temperature is preferably 800°C or higher, preferably 1000 to 1500°C.

Next, the present invention will be specifically explained using examples.

Example 1 Furan resin (Hitafuran VF302 manufactured by Hitachi Chemical Co., Ltd.)
80% by weight, natural graphite scale (Nippon Graphite Co., Ltd. CSP-E)
After uniformly mixing 20% by weight with a Henschel mixer, knead using three rolls heated to 40℃ until the binder resin component is homogeneously mixed with graphite by mechanochemical phenomenon, and then caking. When the resin component starts to polymerize and the whole becomes slightly thickened, it is collected. The paste recovered had a viscosity of 20 poise at 25°C.

Next, 0.1% by weight of a furan resin curing agent (A ₃ curing agent manufactured by Hitachi Chemical Co., Ltd.) was added to the total amount of the paste, stirred and defoamed, and then coated with a reverse roll coater to a width of 300 mm and a thickness of 0.3 mm. The composition was coated onto a paper surface treated with silicon in the same manner as described above, and cured for 5 minutes at 70°C to obtain a sheet of the composition. Next, the obtained sheet was cut to a length of 300 mm, placed in an oven, and gradually heated from room temperature to 180°C after 6 hours, and kept at the same temperature for 3 hours to make the composition infusible. 20℃/h up to 500℃ in atmosphere, up to 1000℃
The product was heated at a rate of 100° C./h, carbonized, and cooled to obtain a product. The obtained hard carbonaceous plate has a thickness of 0.2 mm and 255 mm.
The corner dimensions were maintained with high precision and the surface was smooth. The bending strength of the plate was 30Kg/ ^mm2 .
The air permeability was 8×10 ⁻¹¹ cm ² /s.

Example 2 75% by weight of bismaleimide triazine resin (BT-2100 manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 25% by weight of natural earthy graphite were put into a Banbury mixer, and the temperature inside the tank was raised to 100%.
The mixture was kneaded for 20 minutes while maintaining the temperature at 0.degree. C. to obtain a paste containing carbon particles to which graphite was bonded to a resin component generated by a mechanochemical phenomenon. The recovered paste was solid at room temperature, but had a viscosity of 5 poise at 100°C. Next, the paste was cast onto a ground glass plate to a thickness of 1 mm in an atmosphere of 100°C. Next, the composition was placed in a heated oven at 180°C and held for 10 hours to make the composition infusible. After cooling, the composition was taken out and cut into 300 mm square pieces, and baked in a nitrogen gas atmosphere under the same conditions as in Example 1 to obtain a product. I got it. The obtained hard carbonaceous plate maintained the dimensions of 0.7 mm thick and 240 mm square with high precision, and had a smooth surface and a surface that traced the matte surface of ground glass with high precision on the opposite side. The bending strength of the plate was 25Kg/ ^mm2 . The air permeability was 5×10 ⁻¹⁰ cm ² /s.

Example 3 Furan resin (Promitate manufactured by Takeda Pharmaceutical Co., Ltd.)
Q1001) Put 90% by weight of carbon black (Mitsubishi Kasei Corporation MA-8) into a rotating ball mill,
The composition was collected after three days of operation. The viscosity of the composition was 15 poise at 25°C. Next, 0.5% by weight of a hardening agent (Promitate Q-2001, manufactured by Takeda Pharmaceutical Co., Ltd.) was mixed uniformly with the total amount of the paste, and after degassing, it was coated with a reverse roll coater to a width of 300 mm.
Coated on paper surface treated with silicone to 0.1 mm,
The coating was kept in an oven at 60°C for 5 minutes to cure it into a film, then cut into 300mm lengths, placed in an oven, and heated from room temperature to 180°C over 6 hours to infusible the composition. A product was obtained by firing under the same conditions as in Example 1. The hard carbon plate obtained had a thickness of 0.07 mm, dimensions of 250 mm square with good precision, and a smooth surface. The bending strength of the plate was 45Kg/ ^mm2 . Air permeability is 6×10 ^-12 cm ² /s
It was hot.

Claims (1)

[Scope of Claims] 1. A thermosetting resin monomer, prepolymer, or low polymer, which is a substance that shows a high carbon residue yield after firing and can be relatively easily polymerized, is added to fine carbon powder as a binder. A species or a mixture of two or more species is uniformly dispersed, and mechanical energy is applied to induce a mechanochemical phenomenon to uniformly and physicochemically harden the binder to the surface of the primary particles of the fine powder. Obtain a bonded paste-like composition for molding, shape the composition into a film or sheet using a casting method or a coating method, perform an infusibility treatment, and then sinter in an inert gas atmosphere. A method for manufacturing a hard carbon plate, characterized by: 2 The viscosity of the molding paste composition is 100°C.
The manufacturing method of item 1, wherein the manufacturing method is 100 poise or less.