JPH0723259B2 - Impermeable carbon material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an impermeable carbon material suitable for various sealing materials, sliding materials, heat exchanger materials, fuel cell materials, chemical reactor materials, and the like. (Including graphitized).

(Prior Art) The following are conventionally known as impermeable carbon materials.

(1) Carbon, graphite or their precursors as an aggregate,
Resin with thermosetting resin such as unsaturated polyester resin, epoxy resin, phenol resin, furan resin, diallyl phthalate resin, urea resin, melamine resin, xylene resin, polyimide resin, polyurethane resin, polydivinylbenzene resin as binder or matrix Carbonized or graphitized molded and cured product.

(2) A material obtained by impregnating a carbon material, a graphite material, or a processed product thereof with the same thermosetting resin as in (1), and then curing the cured product to carbon or graphitized.

(3) A carbonized product obtained by impregnating the carbonized product obtained in (1) and (2) with a thermosetting resin similar to that in (1), followed by carbonization, and further graphitization.

(Problems to be Solved by the Invention) However, the conventional impermeable carbon material has a low carbonization yield (residual coal rate) of the thermosetting resin used as a binder or an impregnating agent, and therefore is not suitable for carbonization. As a result, a large volume contraction occurs, and the aggregate (impregnated material) and the binder (impregnating resin) are separated or cracked,
It has a drawback that properties such as impermeability, dimensional stability and strength are deteriorated. For this reason, impregnation-firing must be repeated many times.

On the other hand, in Japanese Patent Laid-Open No. 60-260469, organic synthetic fibers are infusibilized and impregnated with a thermosetting resin,
A method of curing and firing is described, and the generation of cracks is prevented by balancing the shrinkage of the organic synthetic fiber and the thermosetting resin, but as a thermosetting resin, phenol with a low carbonization yield is used. Since the resin and the furan resin are used, the volume shrinkage due to carbonization cannot be eliminated, and there is a drawback that a large size and a complicated shape cannot be formed.

(Means and Actions for Solving Problems) The present invention relates to a carbonization or graphitization of a thermosetting composition comprising an aggregate and a thermosetting composition having a high carbonization yield and a small shrinkage during carbonization. It is an object of the present invention to provide an impermeable carbon material suitable for various sealing materials, sliding materials, heat exchanger materials, fuel cell materials, chemical reactor materials, etc. The above object can be achieved by providing the impermeable carbon material described in the claims.

Next, the present invention will be described in detail.

That is, the present invention provides (a) a fused polycyclic aromatic compound having two or more rings, which has at least one element selected from oxygen, sulfur, and halogen in the molecule.

(B) An aromatic cross-linking agent comprising one or two or more aromatic rings having at least one group of at least one of a hydroxymethyl group and a halomethyl group.

(C) Acid catalyst.

A mixture of the above (a), (b) and (c), or the above (a)
(B) At least one thermosetting composition selected from among thermosetting intermediate reaction products having substantially thermoplasticity obtained by reacting a mixture of (c) and (c) with a modified COPNA resin composition ) And an aggregate, a thermosetting material is carbonized or graphitized, and the present invention relates to an impermeable carbon material.

In the present invention, the modified COPNA resin composition is composed of an aromatic skeleton, and oxygen or sulfur or halogen in the molecule acts to increase the crosslink density, so that carbon having excellent impermeability called so-called glassy carbon is formed by carbonization. The material is obtained.

Further, the modified COPNA resin composition has a high carbonization yield, and particularly when a heavy oil-based or pitch-based condensed polycyclic aromatic compound is used, the carbonization yield is significantly increased, and therefore, during carbonization Has a small shrinkage, and it is possible to obtain an impermeable carbon material having a large size or a complicated shape. Further, although the modified COPNA resin composition reacts in a solvent-free system, the viscosity can be freely adjusted by changing the reaction conditions so that impregnation is easy to occur, and even if the viscosity is changed, the carbonization yield is almost zero. It has characteristics that do not affect it. Furthermore, by using the modified COPNA resin composition, it is possible to obtain an impermeable carbon material whose size and shape can be freely controlled without being limited to a special molding method.

Hereinafter, the condensed polycyclic aromatic compound, the aromatic cross-linking agent, the acid catalyst, and the aggregate that constitute the modified COPNA resin composition of the present invention will be described.

The fused polycyclic aromatic compound of two or more rings having at least one element of oxygen, sulfur or halogen in the molecule of the present invention is an oxide of at least one substance shown in (a) to (e) below. , Sulfides or halides can be used.

(A) Naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, acenaphthene, acenaphthylene, perylene, derivatives having at least one main skeleton selected from coronene, (I) heavy coal-based oil, (U) petroleum Heavy oil of type, (E) tar, (O) pitch.

Further, oxygen, sulfur or halogen contained in the molecule may exist as a functional group or may exist in the ring, and the number thereof is not limited.

Next, the aromatic cross-linking agent of the present invention includes an aromatic compound consisting of one or more aromatic rings having at least two groups of at least one of hydroxymethyl group and halomethyl group, such as p-xylylene dichloride. , 1,4-
Benzenedimethanol (p-xylylene glycol),
9,10-anthracene dimethanol and the like can be used.

Further, the acid catalyst of the present invention is one or two selected from Lewis acids such as aluminum chloride and boron fluoride, or protic acids such as sulfuric acid, phosphoric acid, organic sulfonic acid and carboxylic acid, and derivatives thereof. Mixtures of more than one can be used.

Regarding the mixing ratio for the condensed polycyclic aromatic compound, the aromatic crosslinking agent, and the acid catalyst to be the modified COPNA resin composition,
Aromatic cross-linking agent / condensed polycyclic aromatic compound = 0.5 to 4.0 (molar ratio);
A suitable range is 0.5 to 10 wt% with respect to the mixture of condensed polycyclic aromatic compounds.

Further, a reaction temperature for obtaining a thermosetting intermediate reaction product (B-stage resin) having substantially thermoplasticity, which is obtained by heating and reacting a mixture of the condensed polycyclic aromatic compound, the aromatic crosslinking agent, and the acid catalyst. About a range, 60-300 degreeC is a suitable range.

Next, as the aggregate in the present invention, carbon, graphite, or a precursor thereof, or a carbon precursor such as a cured product of a natural polymer or a synthetic polymer can be used.

Next, in the case of producing the impermeable carbon material of the present invention,
The modified COPNA resin composition; (1) as an unreacted powder mixture, (2) by heating and melting the powder mixture into a liquid state, (3) as so-called B-stage resin powder, and (4) so-called B-stage resin. It can be used as a liquid by melting it, or (5) as a liquid by dissolving a so-called B-stage resin in a solvent; it can be used as a binder, matrix, impregnating agent, coating agent, etc., in which case the form of aggregate is; continuous fiber In the case of a sheet, a woven fabric, a non-woven fabric, or a porous body, the impregnation method, filament winding method, prepreg method or the like is adopted by the method of (2), (4) or (5); In the case of a shape, a granular shape, a plate shape, a lump shape, etc., the kneading method by the method of (1) or (3)
Adopt granulation method, coating method, etc .: (2), (4) or (5) in case of block shape, flat plate shape, processed product etc.
By adopting an impregnation method or the like according to the above method, it is preferable to combine them respectively.

Also, when molding is required, hot pressing, molding, hydrostatic pressure, vibration, extrusion, injection, transfer, vacuum,
A molding method suitable for the purpose is selected from among spraying, winding, and laminating, and thermosetting molding is performed into a predetermined shape. At this time, the molding temperature range is preferably 100 to 400 ° C., and it is desirable to set the molding temperature and time so that the composite is thermoset after plasticized.

Regarding the curing treatment, post-curing treatment may be further performed after molding and curing. In this case, the post-curing temperature is 100-400 ℃
Is suitable, and the post-curing time is preferably 10 to 30 hours.

An impermeable carbon material can be obtained by carbonizing the molded and cured product, or a product obtained by post-curing the molded and cured product, by carbonization or by graphitization. The carbonization and graphitization are performed in a non-oxidizing atmosphere according to a conventional method.

In the present invention, when a heavy oil-based or pitch-based fused polycyclic aromatic compound is used, a much higher carbonization yield can be obtained as compared with the conventional thermosetting resin, and therefore volume shrinkage is caused. It is possible to obtain an impermeable carbon material having a small size, which can be fired at a temperature rising rate faster than conventional ones, and which has a large size.

(Examples) Next, the present invention will be described in more detail with reference to Examples.

Example 1. Commercially available calcine pitch coke crushed to 150 mesh or less was used as an aggregate. As the modified COPNA resin composition,
Air-blown coal-based pitch (average molecular weight of about 400) with a softening point of 59 ° C. and p-xylylene dichloride were mixed at a molar ratio of 1: 2, and p-toluenesulfonic acid was added thereto at 5 wt%.
The added mixture was used. Volume ratio of this mixture to aggregate
The ingredients were mixed at a ratio of 1: 1 and kneaded with a kneader at 140 ° C for 30 minutes. The kneaded product was injection molded into a size of 10 × 100 × 100 mm at a mold temperature of 200 ° C., and then post-cured at 200 ° C. for 20 hours.
This molded body is heated in a high-frequency induction furnace in a non-oxidizing atmosphere at 10 ° C / h.
Graphitization was performed by heating to 2000 ° C. at a heating rate of r. The linear shrinkage ratio of this molded product due to carbonization and graphitization was about 10%. The graphitized product thus obtained exhibited a gas permeability of 10 ⁻⁵ cm ² /sec.cmHg or less with respect to nitrogen gas.

Example 2. Commercially available phenol resin fiber (trade name: Kynol paper, manufactured by Gunei Chemical Co., Ltd.) was cut into 200 mm square pieces to obtain an aggregate. As the modified COPNA resin composition, β-naphthol and p-xylylene glycol were mixed at a molar ratio of 1: 2, and p-toluenesulfonic acid was added thereto in an amount of 3% by weight.
A B-stage resin reacted at 40 ° C. for 40 minutes was used. The obtained B-stage resin was impregnated into the phenol resin fiber at 150 ° C., five sheets were laminated, and hot pressed at 180 ° C. The molded body should be 1 at a heating rate of 10 ° C / hr in a non-oxidizing atmosphere.
It was baked up to 000 ° C. This baked product is 10 against helium.
^It showed a gas permeability of ^-8 cm ² /sec.cmHg or less. The bending strength of the fired product was 2200 Kg / cm ² .

Example 3. A modified COPNA resin composition obtained in Example 1 was applied to a graphite pipe (outer diameter 20 mm, inner diameter 16 mm, length 200 mm) manufactured by processing a commercially available graphite material having a porosity of 16% at 150 ° C. The molten solution was impregnated, heat-cured at 200 ° C. for 1 hour, and then post-cured at 250 ° C. for 10 hours. Further, it was fired up to 1000 ° C. at a heating rate of 20 ° C./hr in a non-oxidizing atmosphere. Both ends of this graphite pipe were sealed and the impermeability was measured.
The gas permeability was 10 ^-6 cm ² /sec.cmHg or less.

Example 4. Petroleum-based raw coke was crushed to 10 μm or less in the air by an ultrafine crusher and used as an aggregate. As the modified COPNA resin composition, coal-based air blow pitch having a softening point of 115 ° C. (average molecular weight of about 600) and p-xylylene glycol were mixed at a molar ratio of 1: 2, and p-toluenesulfonic acid was added thereto. A B-stage resin obtained by reacting the mixture added with 5 wt% at 130 ° C. for 30 minutes was used. This B-stage resin is crushed to 40 μm or less, and this is used as a binder in a weight ratio of 2: 1 with the aggregate.
Was mixed at a ratio of 100 ° C., molded into a size of 100 mmφ × 10 mmt at 180 ° C., and then post-cured at 200 ° C. for 15 hours. The molded body was fired up to 1000 ° C in a non-oxidizing atmosphere at a temperature rising rate of 10 ° C / hr. The bending strength of this fired product was 4200 Kg / cm ² . It also showed a gas permeability of less than 10 ^-8 cm ² /sec.cmHg for helium.

Example 5 The carbonization yield of the B-stage resin containing no aggregate obtained in Example 4 was measured. Carbonization yield of baked products at 1000 ℃ is 82
%showed that.

(Effects of the Invention) As described above, according to the present invention, the crosslink density is increased by oxygen, sulfur, or halogen in the molecule constituting the modified COPNA resin composition, and by carbonization, the impermeability of so-called glassy carbon is called. In addition, the modified COPNA resin composition has a high carbonization yield, and therefore, the shrinkage during carbonization is small, and thus a large size or an impermeable carbon material having a complicated shape is obtained. be able to. Further, when the aggregate is a carbon precursor, of course, even when the aggregate is made of carbonaceous or graphite, since the difference in shrinkage between the aggregate and the modified COPNA resin composition is small The incidence is extremely low. Furthermore, it is not necessary to repeat impregnation-firing repeatedly in order to obtain impermeability unlike the conventional case.

In the present invention, particularly when a heavy oil-based or pitch-based condensed polycyclic aromatic compound is used, a much higher carbonization yield can be obtained as compared with the conventional thermosetting resin, and volume shrinkage is small. It is possible to obtain an impermeable carbon material having a large size and a complicated shape, which can be fired at a higher heating rate.

Further, according to the present invention, the modified COPNA resin composition reacts in a solventless system, but the viscosity can be freely adjusted so that impregnation is easily performed, and the molding method is also hot pressing, molding, hydrostatic pressure, You can freely select the method that suits your purpose from among vibration, extrusion, injection, transfer, vacuum, blowing, winding, and laminating.

From the above, the impermeable carbon material of the present invention is suitable for various sealing materials, sliding materials, heat exchanger materials, fuel cell materials, chemical reactor materials, etc. The effect that makes a large contribution to the above is considered.

Claims (5)

[Claims] 1. (a) Two or more condensed polycyclic aromatic compounds having at least one element of oxygen, sulfur or halogen in the molecule; (b) at least one of hydroxymethyl group or halomethyl group An aromatic cross-linking agent consisting of one or two or more aromatic rings having two or more groups; (c) an acid catalyst; a mixture of (b), (b) and (c); or (a).
(B) Thermosetting comprising at least one thermosetting composition selected from among thermosetting intermediate reaction products having thermoplasticity obtained by reacting the mixture of (c) with heating, and an aggregate An impermeable carbon material, characterized in that an object is carbonized or graphitized. 2. The impervious carbon material according to claim 1, wherein the condensed polycyclic aromatic compound of (a) is
An impermeable carbon material characterized by being an oxide, sulfide or halide of at least one substance shown in (a) to (o) below: (a) naphthalene, anthracene, phenanthrene, pyrene, chrysene, A derivative whose main skeleton is at least one selected from naphthacene, acenaphthene, acenaphthylene, perylene, and coronene, (i) heavy oil of coal, (u) heavy oil of petroleum, (e) tar, (o) )pitch. 3. The impervious carbon material according to claim 1, wherein the acid catalyst (c) is aluminum chloride, boron fluoride, phosphoric acid, organic sulfonic acid, carboxylic acid, or a mixture thereof. An impermeable carbon material, which is one kind or a mixture of two or more kinds selected from derivatives. 4. The impervious carbon material according to claim 1, wherein the aggregate is carbon, graphite, or a precursor thereof, or carbon such as a cured product of a natural polymer or a synthetic polymer. An impermeable carbon material, which is one or more compounds or mixtures selected from precursors. 5. The impermeable carbon material according to claim 1, wherein the form of the aggregate is a continuous fibrous form, a short fibrous form, a granular form, a flat plate form, a lump form, a block form, a porous body form, An impermeable carbon material, characterized in that it is composed of one kind or a combination of two or more kinds selected from a woven cloth shape and a non-woven cloth shape.