JPH0717449B2 - Method for producing 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. The present invention relates to a method for producing (including graphitized).

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

(1) Carbon, graphite or their precursors as an aggregate,
Thermosetting resins 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, and silicone resin are used as a binder or matrix. The carbonized or graphitized cured resin molded product.

(2) A carbon material, a graphite material, or a processed product thereof is impregnated with the same thermosetting resin as in (1), and then the cured product is fired to be carbonized, or further the carbonized product is (1). ) Carbonized by impregnating a thermosetting resin similar to the above), and further graphitized.

Of these, graphite fine powder as an aggregate, phenolic resin,
Japanese Patent Laid-Open Nos. 59-232906 and 60-42212 disclose methods for carbonizing a furan resin as a binder after hot press molding.

(Problems to be solved by the invention) Recently, impermeable carbon materials used as various sealing materials, Shu moving materials, heat exchanger materials, fuel cell materials, and chemical reactor materials are impervious. At the same time, it is desired to combine excellent properties such as heat resistance and chemical resistance with dimensional stability, strength, toughness, and abrasion resistance.

However, in conventional impermeable carbon materials, thermosetting resin used as a binder or as an impregnating material forms so-called impermeable so-called glassy carbon by carbonization, but basically carbonization of thermosetting resin Since the yield (remaining coal rate) is low, a large volume contraction occurs due to carbonization, and the aggregate (impregnated material) and the binder (impregnating agent) are peeled off or cracked, resulting in impermeability. However, it has a drawback that properties such as property, dimensional stability, strength, toughness and abrasion resistance are deteriorated.

Further, in the conventional production of the impervious carbon material by impregnation, the carbonization yield of the impregnating agent is low, so that the impregnation-calcination must be repeated many times.

Further, in the conventional impermeable carbon material, the bond between the aggregate (impregnated material) and the binder (impregnating agent) depends on the physical adhesion (anchor effect), and therefore, particularly strength, toughness, It was not possible to obtain an impermeable carbon material having excellent wear resistance.

In JP-A-59-232906 and JP-A-60-42212, it is described that a chemical bond is introduced between the aggregate and the binder by oxidizing the aggregate,
There is no description of a specific cross-linking agent that chemically bonds the aggregate and the binder, and the binder uses a phenol resin or furan resin with a low carbonization yield. Indicates volume contraction. For this reason, the manufacturing method is limited to hot press molding (hot pressure molding), and there is a drawback that a large size (particularly in the thickness direction) cannot be performed.

(Means and Actions for Solving Problems) In the present invention, a thermosetting composition having a high carbonization yield and a small shrinkage at the time of carbonization and an aggregate having a surface functional group are combined by an aromatic crosslinking agent. Provided is a method for producing an impermeable carbon material suitable for various sealing materials, sliding materials, materials for heat exchangers, materials for fuel cells, materials for chemical reaction devices, etc. characterized by being firmly bonded. The object is to achieve the above object, and the object can be achieved by providing a method for producing an impermeable carbon material described in claims.

Next, the present invention will be described in detail.

That is, the present invention includes: (a) a condensed polycyclic aromatic compound of two or more rings having at least one element selected from oxygen, sulfur and halogen in the molecule; (b) at least one of a hydroxymethyl group and a halomethyl group An aromatic cross-linking agent comprising one or two or more aromatic rings having two or more groups of the above.

(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 having a surface functional group, at the interface between the modified COPNA resin composition and the aggregate,
The present invention relates to a method for producing an impermeable carbon material obtained by carbonizing or graphitizing a thermosetting material having a bond through a surface treatment agent or an additive mainly composed of the aromatic cross-linking agent (b). is there.

In the present invention, oxygen, sulfur, or halogen in the molecule of the modified COPNA resin composition increases the crosslink density, and the carbon material obtained by carbonization becomes a so-called glassy carbon having excellent impermeability. Further, particularly when a heavy oil type or pitch type condensed polycyclic aromatic compound is used, the carbonization rate is dramatically improved, and for example, a carbonization yield exceeding 80% can be obtained. Therefore, the shrinkage during carbonization is small.

Further, since the modified COPNA resin composition and the aggregate having a surface functional group are firmly bonded by the aromatic cross-linking agent, they are integrated and carbonized during carbonization. Due to these effects, it has heat resistance, chemical resistance, dimensional stability, strength, toughness, and wear resistance, and is impervious to size and shape that can be freely controlled without being limited to any particular molding method. A carbonaceous material can be obtained.

Hereinafter, the condensed polycyclic aromatic compound, the aromatic cross-linking agent and the acid catalyst constituting 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. , Sulfur compounds 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.

In order to obtain a particularly high carbonization yield, it is preferable to use a coal-based or petroleum-based heavy oil, tar, or 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 derivatives thereof 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, regarding the surface treatment agent and the additive in the present invention, an aromatic cross-linking agent consisting of one or more aromatic rings having at least two groups of at least one of a hydroxymethyl group or a halomethyl group, or the above A mixture of an aromatic cross-linking agent and the above-mentioned acid catalyst is used, and these can be used as a liquid obtained by heating and melting at a temperature above the melting point of the above substance, or as a solution dissolved in a solvent. Further, the amount of the surface treatment agent or the additive added to the aggregate is not particularly specified, but 0.01 to
A range of 5 wt% is preferred.

Next, as the aggregate in the present invention, hydrogen, halogen,
Carbon, graphite, expanded graphite, or those having on the surface at least one kind or two or more kinds selected from a hydroxyl group, a carbonyl group, a carboxyl group, an aldehyde group, an epoxy structure, a lactone structure, an ether structure and an acid anhydride structure. A polymer material such as a precursor of or a thermosetting resin cured product can be used. Regarding the surface functional groups etc. of the aggregate, those existing in advance as they are,
If there is a small amount of other substances, it is effective to use wet oxidation with an oxidant, dry oxidation with oxygen, or reduction treatment with hydrogen, or introduction with plasma treatment using oxygen gas, hydrogen gas, or the like. is there.

Next, as the production method of the present invention, a method of previously treating the aggregate surface with a surface treatment agent, and a method of adding the surface treatment agent as an additive to the modified COPNA resin composition can be used. It can be used as a solution by heating and melting a surface treatment agent or an additive at a temperature above their melting point, or by dissolving it in a solvent. Among these, the surface treatment agent is dissolved in a solvent and used as a solution. It is preferable to use an aggregate whose surface has been treated in advance.

According to the present invention, the modified COPNA resin composition is: (1) as an unreacted powder mixture, (2) the powder mixture is heated and melted into a liquid state, (3) a so-called B-stage resin powder, (4) The so-called B-stage resin is heated and melted into a liquid state, or (5) the so-called B-stage resin is dissolved into a solvent to be a liquid state; binder, matrix, impregnating agent,
It can be used as a coating agent or the like, and in that case, when the form of the aggregate is continuous fiber, woven fabric, non-woven fabric, or porous body, (2), (4) or (5) ), An impregnation method, a filament winding method, a prepreg method, etc. are adopted; in the case of single fiber, granular, flat plate, lump, etc., the kneading method, the production method, or the like by the method of (1) or (3). Grain method, coating method, etc. are adopted; (2) in case of block shape, flat plate shape, processed product, etc.
According to the method (4) or (5), a coating method, an impregnation method or the like is adopted;

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 softening.

In the manufacturing method of the present invention, post-curing treatment may be further performed after molding and curing. In this case the post-cure temperature is 100-400
C is a suitable range, and the post-curing time is preferably in the range of 10 to 30 hours.

Then, in the production method of the present invention, the molded cured product,
Alternatively, the molded and hardened material is post-cured to be carbonized by firing or further graphitized to obtain an impermeable carbon material. Further, the modified COPNA resin composition of the present invention is impregnated or coated on a carbon material which has been processed into a predetermined shape in advance, and after curing, it is carbonized by firing or further graphitized to obtain an impermeable carbon material. You can also The carbonization and graphitization are performed in a non-oxidizing atmosphere according to a conventional method. Especially heavy oil type or pitch type modification
Since the COPNA resin composition has a much higher carbonization rate than the conventional thermosetting resin, it has a small volume shrinkage and can be fired at a faster heating rate than the conventional one, and a large size can be obtained. Further, in the case of impregnation, it is not necessary to repeat impregnation-firing as in the conventional case.

As described above, heat resistance, chemical resistance, dimensional stability, strength,
An impermeable carbon material rich in toughness, body wearability, etc. can be obtained.

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

Example 1. Commercially available calcine pitch coke pulverized to 150 mesh or less was heated in air at 400 ° C. for 3 hours to introduce a functional group containing oxygen on the surface, and then this was used as an aggregate. Modified COPN
As the A resin composition, air-blown coal-based pitch (average molecular weight of about 400) having a softening point of 59 ° C. and p-xylylene dichloride were mixed at a molar ratio of 1: 2, and anhydrous aluminum chloride was used as an acid catalyst. Was used in an amount of 5.0 wt%. This mixture and the aggregate were mixed in a volume ratio of 1: 1 and p-xylylene dichloride was added to the aggregate as an additive.
After adding 1.0 wt%, the mixture was 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 cured product is heated in a high frequency induction furnace at 10 ° C in a non-oxidizing atmosphere
Graphitized by heating to 2000 ° C at a heating rate of / hr. The carbon material thus obtained is 10 ^-5 cm 2 against nitrogen gas.
The gas permeability was less than ² /sec.cmHg. The bending strength of this carbon material was 1800 kg / cm ² .

Example 2 A petroleum-based raw coke was pulverized to 10 μm or less in air by an ultrafine pulverizer, and a surface functional group containing oxygen was introduced at the same time as pulverization, and this was used as an aggregate. Softening point of 115 for binder
℃ coal-based air blow pitch (average molecular weight about 600) and p-
Mixing xylylene glycol in a molar ratio of 1: 2,
A B-stage resin obtained by reacting a mixture prepared by adding 3.0 wt% of p-toluenesulfonic acid thereto at 120 ° C. for 15 minutes was used. This B-stage resin was crushed to 40 μm or less, and this was mixed with the aggregate in a weight ratio of 2: 1. As an additive, p-xylylene glycol was added to the aggregate in an amount of 1.0 wt% and p-toluene. 100mmφ × 1 at 180 ℃ after adding 1.0wt% of sulfonic acid
After injection molding to a size of 0 mmt, 1 at 200 ℃
Post-cured for 5 hours. This was heated to 1000 ° C. in a non-oxidizing atmosphere at a heating rate of 5 ° C./hr to carbonize it. This carbon material exhibits a bending strength of 3800 kg / cm ^{2 and} is 10 against helium.
^It showed a gas permeability of ^-8 cm ² /sec.cmHg or less.

Example 3. The carbon material obtained in Example 1 was cut into a piece of 20 mm square and immersed in 98% phosphoric acid at 200 ° C. After 1400 hours, no dimensional change was observed and the weight change was within ± 0.01%.

(Effect of the invention) As described above, the impermeable carbon material obtained by the production method of the present invention has a crosslink density due to oxygen, sulfur or halogen in the molecule of the condensed polycyclic aromatic compound constituting the modified COPNA resin composition. Is enhanced, and due to carbonization, it becomes so-called glassy carbon with excellent impermeability, further has heat resistance and chemical resistance, and the carbonization yield of the modified COPNA resin composition is high, Since the shrinkage is small, it is also excellent in dimensional stability, and further, the modified COPNA resin composition and the aggregate having a surface functional group are firmly bonded by an aromatic cross-linking agent, resulting in strength, toughness, and wear resistance. Is also excellent.

Further, in the present invention, the molding method can be freely selected from among hot pressing, molding, static pressure, vibration, extrusion, injection, transfer, vacuum, blowing, winding, laminating and the like, depending on the purpose. Suitable for various sealing materials, sliding materials, heat exchanger materials, fuel cell materials, chemical reactor materials, etc.

Further, in the present invention, an impermeable carbon material having a particularly high carbonization yield can be obtained by using a condensed polycyclic aromatic compound such as coal-based or petroleum-based heavy oil, tar and pitch. For this reason, the one having a larger size than the conventional one can be fired at a higher heating rate, and it is not necessary to repeat the impregnation-firing many times in order to obtain the impermeability unlike the conventional one. Due to these advantages, a significant cost reduction is expected, and it is considered that it will have a great effect on the industry.

Claims (10)

[Claims] 1. A method for producing an impermeable carbon material, which comprises the following sequences (a) to (d): (A) the surface of an aggregate having at least one selected from hydrogen, halogen, hydroxyl group, carbonyl group, carboxyl group, aldehyde group, epoxy structure, lactone structure, ether structure, and acid anhydride structure on the surface, A step of performing a heat treatment after treating with a surface-treating agent mainly containing an aromatic cross-linking agent having one or more aromatic rings having at least one group of at least one of hydroxymethyl group or halomethyl group; (B) (a) Bicyclic or more condensed polycyclic aromatic compound having at least one element of oxygen, sulfur or halogen in the molecule: (b) at least one group of hydroxymethyl group or halomethyl group Aromatic cross-linking agent consisting of one or two or more aromatic rings having two or more: (c) Acid catalyst: Previous A mixture of (a), (b) and (c), or the above (a)
(B) At least one thermosetting composition selected from the thermosetting intermediate reaction products having substantially thermoplasticity obtained by reacting the mixture of (c) with heating, and obtained by the step (a). (C) heating the composite obtained by the step (b) in an oxidizing or non-oxidizing atmosphere to a temperature range of 100 to 400 ° C.,
Molding and hardening step of plasticizing and then thermosetting molding into a predetermined shape; (d) step of carbonizing or graphitizing the molding and hardening product. 2. The manufacturing method according to claim 1, wherein the surface treatment agent is a liquid obtained by heating and melting the surface treatment agent,
Alternatively, it is used as a solution dissolved in a solvent, which is a method for producing an impermeable carbon material. 3. The method according to claim 1, wherein the thermosetting intermediate reaction product is obtained by mixing the mixture of the thermosetting composition in an oxidizing or non-oxidizing atmosphere in an amount of 60 to 300.
A method for producing an impermeable carbon material, which is a reaction product having substantially thermoplasticity obtained by heating and reacting in a temperature range of ° C. 4. The production method according to claim 1, wherein the thermosetting composition is an unreacted mixture, which is a powder or a liquid obtained by heating and melting the powder, a binder and a matrix. A method for producing an impermeable carbon material, which is used as an impregnating agent or a coating agent. 5. The manufacturing method according to claim 1, wherein the thermosetting composition is a thermosetting intermediate reaction product, which is a powder or a liquid obtained by heating and melting the powder, Alternatively, a method of producing an impermeable carbon material, which is used as a binder, a matrix, an impregnating agent, or a coating agent in a solution dissolved in a solvent. 6. A method for producing an impermeable carbon material, which comprises the following sequences (a) to (c): (A) (a) Bicyclic or more condensed polycyclic aromatic compound having at least one element of oxygen, sulfur or halogen in the molecule: (b) at least one group of hydroxymethyl group or halomethyl group Aromatic cross-linking agent consisting of one or more aromatic rings having two or more: (c) acid catalyst: a mixture of the above (a), (b) and (c), or the above (a)
(B) At least one thermosetting composition selected from the thermosetting intermediate reaction products having substantially thermoplasticity obtained by heating and reacting the mixture of (c) with the aromatic compound of (b) above. An additive comprising a cross-linking agent or a mixture of the above (b) aromatic cross-linking agent and the above (c) acid catalyst is added, and hydrogen, halogen, hydroxyl group, carbonyl group, carboxyl group, and A step of complexing with an aggregate having at least one selected from an aldehyde group, an epoxy structure, a lactone structure, an ether structure and an acid anhydride structure; (b) oxidizing the composite obtained by the step (a) In an oxidizing or non-oxidizing atmosphere to a temperature range of 100-400 ° C,
A molding and hardening step of thermosetting and molding into a predetermined shape after plasticizing; (c) a step of carbonizing or graphitizing the molding and hardening product. 7. The impermeating method according to claim 6, wherein the additive is used in a liquid state in which the additive is heated and melted, or in a solution in which it is dissolved in a solvent. Of producing a porous carbon material. 8. The manufacturing method according to claim 6, wherein the thermosetting intermediate reaction product comprises a mixture of the thermosetting compositions in an oxidizing or non-oxidizing atmosphere in an amount of 60 to 300.
A method for producing an impermeable carbon material, which is a reaction product having substantially thermoplasticity obtained by heating and reacting in a temperature range of ° C. 9. The manufacturing method according to claim 6, wherein the thermosetting composition is an unreacted mixture, which is a powder or a liquid obtained by heating and melting the powder, a binder and a matrix. A method for producing an impermeable carbon material, which is used as an impregnating agent or a coating agent. 10. The manufacturing method according to claim 6, wherein the thermosetting composition is a thermosetting intermediate reaction product, which is a powder or a liquid obtained by heating and melting the powder. Or a solution dissolved in a solvent, which is used as a binder, a matrix, an impregnating agent, or a coating agent, which is a method for producing an impermeable carbon material.