JPS60112609A - Preparation of rigid molded article of carbon - Google Patents

Abstract

PURPOSE:To prepare inexpensively a rigid molded article of carbon with high denseness, high strength and complex shape by mixing low polymer of thermosetting resin with fine carbon particles prepd. by carbonizing mesophase, polymerising a molded product and then curing and calcining. CONSTITUTION:Binder (B) comprising monomer, prepolymer, or low polymer constituting a thermosetting resin which is an org, substance resulting high yield of carbon residue after calcination, such as condensation product in the initial stage of condensation of furan resin, is added and dispersed to (A) fine carbon powder contg. carbonized or graphitized fine powdery mesophase. Then, the product is shaped and polymerized and cured, and, thus, a target rigid molded carbon article is obtd. Above described fine powder obtd. by carbonizing the mesophase is one prepd. by heat treating pitch, fractionating the mesophase formed in the pitch matrix by a fractionating process using a solvent, and heat treating and carbonizing the product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing hard carbon molded articles. fi7+ is a hard carbon molded body having a dense and homogeneous structure, high mechanical strength, and a precise and complex shape. The present invention relates to a manufacturing method using an iS method at low cost and essentially requiring no secondary processing.

Conventionally, hard carbon materials have been obtained by molding and curing organic materials that undergo a solid phase carbonization process, such as various thermosetting resins, and then carbonizing them by gradually raising the temperature. In the case of solid-state carbonization reactions, it is well known that extremely fine micro-cranks exist in the internal structure of carbonized materials because volatile components generated by thermal decomposition due to heating of organic materials escape through the solid phase. . Therefore, in order to carbonize a thermosetting resin, it is necessary to take measures to prevent the occurrence of cracks caused by the thermal decomposition volatile components generated by heating. Firstly, it is necessary to make the curing reaction of the thermosetting resin extremely slow, and the amount of curing agent added should be the minimum amount necessary, so that no curing distortion occurs over long periods of time near room temperature. Curing must be completed at Second, when firing the cured product, the firing process is extremely slow, in order to suppress the generation of volatile components due to thermal decomposition, and at the same time, to allow the generated volatile components to gradually escape to the outside and prevent the occurrence of cracks. It was necessary to carry out the carbonization reaction slowly by heating at a certain temperature increase rate. Conventionally, the first curing reaction involves 3-
It requires a long time of 8 weeks, and the second firing time is also 3
It required a long time of ~12 weeks.

Therefore, as is clear from the above manufacturing process, conventional methods have limitations on the size, thickness, and shape that can be manufactured.
Not only is it extremely difficult to manufacture large, thick, and complicated shapes, but once carbonized, it is extremely hard and has poor workability, making it difficult to form carbon into complex shapes. Obtaining a body was virtually impossible.

In addition to these drawbacks in conventional manufacturing, the manufacturing period is extremely long and the manufacturing cost is extremely high. Therefore, the hard carbon material obtained by carbonizing thermosetting resin is Compared to other materials, it has greater mechanical strength, isotropy, and impermeability.
Although it has excellent characteristics such as a microscopically smooth surface and a small surface area, it can only be used for special purposes and in a limited state, and is hardly used industrially. This is the current situation.

In order to solve these drawbacks, thermosetting resins are made of amorphous carbon fine powder such as coke fine powder or carbon blank, or crystalline carbon fine powder such as artificial graphite or natural graphite, or A method has been considered in which fibrous carbon such as carbon fiber is blended, uniformly dispersed and mixed, then molded, hardened, and carbonized. By uniformly dispersing the fine-grain aggregate, cracks generated during firing are absorbed at the interface between the thermosetting resin matrix and the fine-grain aggregate, and the propagation of cracks is prevented. According to follow-up tests, it was possible to prevent the occurrence of cracks to some extent, but it was difficult to significantly shorten the curing reaction time and carbonization reaction time of thermosetting resins. As with the case of using resin alone, cracks are likely to occur due to rapid reaction, and it does not respond favorably to variations in size, wall thickness, and shape of the molded product, and satisfactory results were not obtained.

The purpose of the present invention is to overcome the above-mentioned drawbacks, and to produce a hard carbon material with high mechanical strength, isotropic impermeability, smooth surface, and small surface area, in dimensions that were conventionally difficult to manufacture. However, it is an object of the present invention to provide a method for manufacturing a carbon molded body having a complicated shape quickly and inexpensively without requiring secondary processing.

In the process of pencil lead manufacturing research, the present inventors uniformly dispersed and mixed various organic materials showing a high carbon residue yield after firing and various carbon fine powders, molded them, and then fired them. Through repeated trial production experiments, we found that when amorphous carbon fine powder such as coke powder or carbon blank is blended, a hard carbon material can be obtained without generating large cracks, but it is easy to produce fine cracks. We discovered that there is a limit to the speed of hardening and firing, and when we blend artificial graphite and natural graphite, which are crystalline carbon fine powders, the crystalline carbon fine powder has a scale-like shape, and each particle has a Since it is two-dimensionally oriented within the molded product, it contributes to the prevention of the occurrence of fine racks and provides favorable dimensional stability during molding.However, during the firing process, thermal expansion of the matrix and the filled carbon body found that deformation tends to occur in the direction perpendicular to the orientation plane of the particles due to the difference in shrinkage rate, and the height of the fired product also decreases as the blending amount increases.

As a result of further intensive research into carbon fine powder, which has the characteristics of combining the advantages of amorphous carbon fine powder and crystalline fine powder and eliminating the drawbacks of both, the present inventors have discovered that carbon fine powder can be caked into fine carbon powder. As a material, one or more types of thermosetting resin monomers, prepolymers, or low polymers, which are organic substances that exhibit a high carbon residue yield after firing, are added, dispersed, mixed, shaped, and then the organic substance is polymerized. In a method of producing a hard carbon molded article by curing and firing in an inert atmosphere,
The above object has been achieved by devising a method for producing a hard carbon molded article, which is characterized in that at least a fine carbonized or graphitized mesophase powder is blended as the fine carbon powder. In other words, fine carbon powder obtained by carbonizing or graphitizing mesophase, which is a fine spherulite, is isotropic and has a small specific surface area.
Since the difference in thermal expansion and contraction rates between the lux and the filled carbon fine powder is minimized, it is possible to significantly prevent the occurrence of cracks in the product during firing.

Monomer of thermosetting resin used in the present invention or 7” L
/ As a 17mer or low polymer, divinylbenzene, methyl vinyl ketone, phenolic resin initial condensate,
Furan resin initial condensate, furfuryl alcohol, furfural, bismaleimide 1-riazine resin, diphenyl oxide, epoxy resin, unsaturated polyester resin, etc. are available, but moldability, shape stability during firing, carbonization reaction rate, etc. From this point of view, one or more of a furan resin initial condensate, a phenol resin initial condensate, and a bismaleimide triazine resin are preferably used.

The carbon fine powder obtained by carbonizing or graphitizing mesophase used in the present invention is pitch such as coal tar pinch, petroleum pitch, or dry distilled pitch: Fi350-45
The mesophase of several microns to tens of microns produced in the pitch matrix by heat treatment to Q, "C" is separated from the pitch matrix using a solvent fractionation method, etc., and if necessary, the mesophase is ~ 45 (l) to adjust the resin remaining in the mesophase and take it out.
18 using air or ozone or other oxidizing gas
After being stabilized by heating to 0 to 350°C, and then carbonized by heating to 800°C or higher, preferably 1000°C or higher, if necessary, further heated to a high temperature of 1800°C or higher, preferably 2000°C or higher. It can be obtained by subjecting it to chemical treatment and graphitization treatment. The proportion of carbonized or graphitized mesophase to be added to the binder depends on the specifications required for the intended hard carbon molded product, but it is
It is good to add 70-t%, more preferably 10-60%. If the amount added is too small, the effect of carbonization or graphitization mesophase will not be expressed and cracks will easily occur during firing, and if the amount added is too large, it will be difficult to degas the air mixed in during dispersion mixing. Furthermore, since the fluidity of the blended composition is reduced, good molding is not possible, and as a result, good products cannot be obtained. In the present invention, the hardness of the hard carbon molded body,
It is also possible to use other carbon fine powders in combination as necessary, taking into account mechanical strength, degree of complexity of shape, surface smoothness, dimensional shrinkage rate during firing, moldability of the compound, etc. . However, it is necessary to keep the amount added to such an extent that the effect of the carbonized or graphitized mesophase does not disappear, and the amount of the carbon fine powder of the carbonized or graphitized mesophase used in combination is 50% or less of the total amount of the two-carbon fine powder. Preferably 40HL%
It is desirable to do the following.

In the method of the present invention, firstly, 95 to 30 wt% of a thermosetting resin monomer, prepolymer or low polymer, and 5% carbon fine powder containing at least a carbonized or graphitized mesophase are used.
~70% of the mixture is uniformly dispersed and mixed using a compounding machine such as a blender or mixer.

At this time, a heating operation is performed as necessary, and a curing agent for the thermosetting resin is added. Next, in order to achieve more uniform dispersion, or to thicken or pre-cure the compound in order to match the optimum conditions of the molding method and molding machine used, heating mixers, mixing rolls, pressure kneaders, It is also good to use a kneader such as a co-kneader or a rotary ball mill.

The molding composition obtained by the above operation is a liquid substance,
It can be obtained in the form of a semi-fluid substance, pellet-like substance, meat-like substance, powder-like substance, etc., and at this time, a degassing operation and a defoaming operation are added as necessary.

Next, the molding composition is shaped into a desired shape using the most appropriate molding method, although this varies depending on the intended product shape and the state of the molding composition. As the molding method, methods commonly used for molding thermosetting resins such as casting, extrusion molding, injection molding, vacuum molding, meeting roll molding, compression molding, and trasfer molding can be used. The product shaped by the molding operation is obtained by solidifying the thermosetting resin as a binder for a short period of time under exactly the same curing conditions as general thermosetting resins, and then taking it out to form a shaped product.

The excipient obtained by the above operation may be
Further infusibility treatment is performed in a heating oven at ~300°C. After that, the product is placed in a carbonization furnace and heated from room temperature in an inert atmosphere such as nitrogen or argon to a temperature of 800°C or higher, preferably 1000°C or higher to carbonize the product, and after cooling, the product is taken out. Get the finished product. The rate of temperature rise varies slightly depending on the type and blending ratio of the thermosetting resin used, but is mostly determined by the wall thickness, and the firing time can be significantly shortened compared to conventional methods. In other words, for products with a wall thickness of 20 mm or less, the temperature is 30 to 0 °C/h between room temperature and 600 °C, and for products with a wall thickness of more than 20 mm and up to about 200 mm, the temperature is 20 to 600 °C between room temperature and 600 °C. C. to 1000.degree. C., it is possible to perform firing at a high temperature increase rate of 70 to 100° C. without generating cracks.

In the above method, the present invention uses a hard carbon molded body with a complicated shape.
Regardless of its size or wall thickness, it can be shaped for efficiency by using a normal thermosetting resin molding method, carbonized in a short time, and has a variety of hard carbon materials with excellent axial characteristics. It can be said that this is a useful invention that makes it possible to supply industrial products at low cost.

Next, the present invention will be explained in more detail with reference to Examples.

A coal tar pinch was treated at 450° C. for 80 minutes to obtain a heat-treated pitch with a quinoline soluble content of 24 wt %. The mesophase of this heat-treated pinch was separated and taken out from the pinch matrix using coal-based medium oil, and further heated to 380° C. in a nitrogen atmosphere to be calcined. Next, the obtained power-calcined product was placed in a heating oven and heat-treated at 200°C for 148 hours in the air, and then gradually heated in a nitrogen atmosphere.
After 8 hours, it was heated to 1000°C, and after cooling, it was taken out and used as a carbonized mesophase. Next, the mixture was heated to 2700° C. in an argon atmosphere at a heating rate of 60° C./h using a graphitization furnace, subjected to graphitization treatment, and taken out after cooling to obtain a graphitized mesophase. The average particle size of the obtained carbonized and graphitized mesophase was 12.5μ.

Next, 72 wt% of a furan resin initial condensate (Prominate Q-1001 manufactured by Narita Pharmaceutical Co., Ltd.) was added to
Graphitized mesophase 28wt heated to 00℃
% using a heating mixer at 60°C for 1 hour. After mixing, take it out and cool it to room temperature.
Brominea Co., Ltd. Q-2001) was added in an amount of 2 wt %, stirred uniformly, and then subjected to vacuum defoaming treatment to obtain a molding composition.

The viscosity of the molding composition obtained was 100 poise at 25°C. On the other hand, using silicone rubber for mold making,
A casting mold was made by making a mold of a hexagonal bolt with a nominal size of M24 specified in JIS B-1180 and a hexagonal nut with a nominal size of M24 specified in JIS B-1181, and the molding composition was heated to 50 ° C. The fluidity was increased, the mixture was poured into a casting mold, and the mixture was heated in a heating oven at 80° C. for 2 hours to solidify, and then taken out from the mold to obtain a shaped product. Next, the excipient was heated in a heating oven from room temperature to 18,080 degrees to perform infusibility treatment. After that, in a nitrogen gas atmosphere at room temperature to 60°C.
25℃/h between 0℃ and 100℃ between 600 and 1000℃
Carbonization treatment was performed by heating at a temperature increase rate of /h, and a product was obtained after cooling. The obtained product showed dimensional shrinkage due to firing, but it had the shape and dimensions of a hexagonal bolt with a nominal M2O specified in JIS B1180 and a hexagonal nut with a nominal M2O specified in JIS B-1181 with good accuracy. The tensile strength of the bolt is 30 kg/m♂ and the shore hardness is 90, and the compressive strength of the hexagon nut is 40 kg/11 m'' and the shore hardness is 90, making it a hex bolt with a smooth surface that does not require secondary processing of hard carbon material. It was a hexagonal Nando.

``Gei'' 1 Masu-''Efuran resin initial condensate (Hitafuran vF- manufactured by Hitachi Chemical)
302) 6 it%, 35-t% of carbonized mesophase prepared by heating to 1000°C in Example 1, and 5% of natural graphite powder (C3P manufactured by Nippon Graphite@) were dispersed at 100°C using a heating mixer. Mix and take out after 2 hours to obtain a semi-fluid blended composition, then thermally polymerize the furan resin initial condensate using three heated rolls to create a sheet-like material, which is then processed using a pellet machine. A pellet for molding with three crane angles was obtained. Next, this was molded using a screw extruder at a die temperature of 80°C, and the thickness was 5 mm, the outer diameter was 60 mm, and the inner diameter was 5 mm.
A pipe-shaped excipient having a length of 0.01 m was obtained. Next, the obtained excipient was cut to 10,100O, heated in a heating oven at 150℃ for 6 hours to perform infusibility treatment, and then heated at 40'C/h between room temperature and 600℃ in a nitrogen atmosphere. Carbonization treatment is performed at a heating rate of 120°C/h between 600 and 1000°C, and after cooling, the fins are taken out and have a wall thickness of 4.4 mm, an outer diameter of 53 mm, and an inner diameter of 44.2 mm.
Obtained brocade pipe material with a length of 880 dragons. The bending strength of the resulting pipe material is 18 kg/+u”, and the shore hardness is 10.
5. Impairment rate 4 x 10 ctA/s (lle
, ΔP=1at+++) A hard carbon pipe shrine having a smooth surface was obtained.

Real JjJLu Bismaleimide triazine resin (Mitsubishi Gas Chemical @ Haisei B
T-; 100) 5.5%, 35% graphitized mesophase prepared by heating to 2700°C in Example 1, and 10wt% carbon blank (MA-100 manufactured by Mitsubishi Kasei@) were heated to 100% using a heating millet. A blended composition was obtained by kneading for 30 minutes while maintaining the temperature at °C. The resulting blended composition was solid at product temperature, but had a viscosity of IO poise at 100°C. Next, 0.5 wt% of each of an organic peroxide and an organic metal salt were added by external scraping so that the prepared composition was completely cured in 10 minutes at 180°C, and mixed uniformly under heating. After treatment, a pellet for molding was obtained using a pellet machine. Next, this was injected into a mold kept at a temperature of 180°C using a thermosetting resin injection molding machine equipped with a turntable, and taken out after 10 minutes with a wall thickness of 2 ms, a height of 25 mm, and an outer diameter of 120 mm. A dragon petri dish-shaped excipient was obtained. The obtained excipient was heated at 35°C between room temperature and 600°C in a nitrogen atmosphere.
/h.

Carbonization was performed at a heating rate of 100°C/h between 600 and 1000°C, and the obtained petri dish-shaped carbonized product was taken out after cooling. Shrinkage due to baking was observed, but the carbonization before carbonization was It was completely similar in shape to the real thing, and had highly accurate dimensions: 1.4 inches thick, 18 mm high, and 85 mm in outer diameter.

The resulting product has an extremely smooth surface and a compressive strength of 35 k.
g/m Shore hardness 110, non-current rate 7 x 1
It was a Petri dish-shaped molded body of hard carbon of 0 csl/s (He, ΔP=latm).

Comparison dish Among the contents of Examples 1 to 3, the blended composition was shaped and cured using exactly the same method as in each example, with the same temperature increase rate except for graphitized mesophase. When taken out after cooling, all comparative examples had cracks, and the hexagonal bolts and hexagonal grooves, which had the same shape as in Example 1, were cracked into chunks and scattered. . The carbon molded bodies of each comparative example were completely useless.

Patent Applicant: Mitsubishi Pencil Co., Ltd. Proceeding Officer (spontaneous) June 1, 1980 Director-General of the Patent Office Kazuo Wakasugi 1, Indication of the Case 1982 Patent Application No. 219203 2, Name of the Invention: Hard Carbon Manufacturing method for molded products 3, relationship with the case of the person making the amendment Patent applicant address: 5-23-37 Higashi-oi, Tokyo Parts Ward Name (5
95) 'Mitsubishi Pencil Co., Ltd. 4, Agent Address ■104 Ginza Dia Heights 410, 8-15-10, Ginza, Chuo-ku, Tokyo Column 6 of [Detailed Description of the Invention] of the Specification, Contents of Amendment (1) "Height" on page 6, line 1 of the specification is corrected to "Hardness 1."

Correct “caking agent” in line 6 to “caking agent”.

(2) Correct "meat-like" in line 1 of page 10 to "sheet-like j.

7-8 lines of “meeting roll” r seating roll”.

(3) Change “Open” in lines 6-7 of page 12 to “Oven 1”.
Correct to.

(4th page 15th line 15th line ``Mikile''
Correct to.

(5) Correct "all molds" in line 5 of page 16 to "r molds".

Claims (1)

[Claims] One or more types of thermosetting resin monomers, prepolymers, or low polymers, which are organic substances that exhibit a high carbon residue yield after firing, are added to fine carbon powder as a binder, and the mixture is dispersed and mixed, and then shaped. A method of manufacturing a hard carbon molded article by subsequently polymerizing and curing the organic substance and firing it in an inert atmosphere, characterized in that at least a fine powder of carbonized or graphitized mesophase is blended as the fine carbon powder. Manufacturing method for hard carbon molded products