JPS5964511A - Preparation of porous carbon - Google Patents

Abstract

PURPOSE:To prepare a porous carbon having mutually interconnected pores, by melting the surface layer of specific organic polymer particles, bonding the particles with each other to form a porous material, making the material insoluble and infusible, and carbonizing the product in an inert atmosphere. CONSTITUTION:Particles of an organic polymer such as a thermoplastic resin (e.g. chlorinated vinyl chloride resin, etc.) and a monomer of a thermosetting resin (e.g. furan resin) having particle diameter of 50mum-5mm. are put into a vessel and heated at a temperature between the softening point and the melting point of the polymer particle. The particles are bonded with each other at points to form a porous organic polymer. The polymer is made insoluble and infusible by heating at 50-300 deg.C in an oxidizing atmosphere or in a corrosive atmosphere such as NH3, Cl2, etc. or by immersing e.g. in concentrated sulfuric acid. The treated polymer is carbonized by heating at >=400 deg.C in an inert gas atmosphere such as Ar, N2, etc. A porous carbon rich in interconnected pores and having high strength and easily controllable porosity and pore diameter can be prepared easily by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a porous carbon material. Specifically, invention 1 relates to a method for producing a carbon porous body rich in continuous pores, that is, 11 large pores are continuous pores.

Conventionally, the method of manufacturing carbon porous bodies involves molding and firing using carbonaceous micro hollow bodies as a binder (!
JP-A-49-19999) Garuru.

However, this method has the disadvantage that most of the pores are independent pores and there are very few continuous pores, resulting in poor air permeability. In order to obtain a carbon porous material with continuous pores, the polyurethane envelop's thin partition walls have been completely removed, and a continuous pore network polyurethane is impregnated with a tetrahydrofuran solution of phenol resin and fired, so that the network polyurethane skeleton of the base material becomes a carbide. Method for obtaining a carbon porous body serving as a skeleton (U.S. Patent 3,9
22,334), but it is necessary to take great care to remove the excess resin on the surface of the polyurethane after resin impregnation, and depending on the selection of solvent, the polyurethane foam may completely dissolve, and when heated The drawback is that there is a risk that the foam will collapse, and this tendency becomes more pronounced as the polyurethane becomes softer. Therefore, before impregnating the polyurethane foam with resin in step 1, liquid epoxy resin is added to the polyurethane foam.
Or a method of pre-impregnation with a polyvinyl alcohol aqueous solution (
However, it cannot be denied that the process becomes complicated. Since polyurethane foam is originally a closed-cell foam, in order to obtain a network structure with open pores, the pore membrane must be removed in advance or a similar treatment must be performed after resin impregnation.

In the latter case, for example, a flammable gas is introduced into a thermosetting resin foam obtained by reacting a mixture of a polyisocyanate and a phenolic resin or a furan resin or its precursor, and the flammable gas is A method of obtaining a porous carbon material having continuous pores by ignition to destroy the diaphragm and then carbonization firing is disclosed (Japanese Patent Laid-Open No. 125289/1989), but the process is extremely complicated and controlling the pore size is even more difficult. be.

As a method for manufacturing a carbon porous material with a uniform pore size distribution and a large continuous porosity, polyvinyl alcohol, phenol resin, a curing agent, starch, water-soluble salts, etc. are mixed and cross-linked, and assimilation and water-soluble substances are removed. A method for producing a carbon porous body consisting at least partially of glassy carbon by firing a phenol/polyvinynoacecool-based synthetic resin porous body which has been eluted with water and has continuous pores (Japanese Patent Application Laid-Open No. 57-511
Publication No. 09) has been disclosed. A polyvinyl acecool porous body with continuous pores containing all inorganic substances or organic substances that can be carbonized is impregnated with phenol or furan resin that can be converted into glassy carbon, and then fired to form a continuous glassy carbon material that is at least partially made of glassy carbon. Method for producing a porous carbon material having pores (! Samurai Kaisho No. 57-51110)
There is. In order to create continuous pores in Shigare polyvinyl acetal, it is necessary to take the troublesome process of pre-mixing water-soluble substances such as starch or water-soluble salts and eluting these after cross-linking, as in the case of Pictorial. Another drawback is that it is extremely difficult and time consuming to completely remove these starches or water-soluble salts from polyvinyl acecool molded products.

The object of the present invention is to create carbon pores that are rich in continuous pores, have easy control of porosity and pore diameter, and have high strength, without using complicated process control methods such as impregnation or elution. The object of the present invention is to provide a method for easily manufacturing a body.

In order to achieve this objective, the inventors of the present application conducted extensive research and found that organic polymer particles were placed in a container of any shape, the surface layer of the particles was melted, and a layer of adhesive metal was formed between the particles to form organic polymer porous particles. The inventors discovered that a porous carbon material, which is basically a granular sintered material, can be obtained by applying an insoluble and infusible treatment to the carbon material and firing it in an inert atmosphere, leading to the present invention.

In the present invention, the organic polymer particles U1 are softened by melting by heating or dissolving by a d solvent to cause point adhesion between particle surface layers, thereby forming an organic polymer porous body. Next, the porous organic polymer is subjected to an insoluble and infusible treatment and carbonized so as to leave the skeleton of the porous organic polymer, thereby obtaining a carbon porous body.

The organic polymer particles in the present invention must first be capable of forming an organic polymer porous body, and secondly must be fired to form a carbon f1-. teeth,
Chlorinated vinyl chloride resin, polyacrylonitrile resin,
Completely remove monomers or initial intoxicants such as particles of thermoplastic resins such as polyvinyl alcohol, polyphenylene chloride, polyamideimide, and polydivinylbenzene, thermosetting resins such as furan resin, enol resin, bismaleimide, and triazine resin. In the stage before three-dimensional crosslinking, that is, the material is hardened to the extent that it can be thermally deformed, and then
Particles pulverized using a sail mill etc., l-lagant gum, gum arabic, natural polymer particles having fused polycyclic aromatics such as saccharides in the basic structure of the molecule, and formalin of naphthalene sulfonic acid, which is not excluded from the above. Synthetic polymer particles having condensed polycyclic aromatics such as condensates, indanthrene dyes and their intermediates in the basic structure of the molecule, carbonized pitch of petroleum asphalt, coal tar pitch, synthetic resin, etc. Appropriately one or two of the particles obtained by heat-treating at °C and removing low-molecular-weight compounds with a solvent, etc.
Select fff1 or more.

Is the polymer particle suitable for the present invention a thermosetting resin such as furan resin or phenol IffJ resin? It does not include particles that are insoluble and infusible and do not weld to each other, such as particles obtained by crushing completely cured particles. Also polyethylene acrylic
If the insoluble and infusible treatment cannot be carried out effectively and the carbon yield after carbonization is less than 5, such as I fat, polyoxymenalene, etc., the carbon pores that can withstand one change after carbonization treatment are used. In addition, it leaves no carbon at all, so it is not included in the organic polymer particles referred to in the present invention.

There is no particular restriction on the shape of the organic polymer particles used in the present invention, but regarding the size, the diameter or maximum side is 5 mrn.
The following particles are preferable, and it is preferable that the diameter or largest side of particles with a coefficient of 80 or more is 50 μm or more. If particles with a diameter or maximum side exceeding 5 mm are used, after firing, the carbonized particles that form the carbon porous body are likely to crack, resulting in a decrease in the strength of the carbon porous body, and a decrease in porosity and porosity. There are drawbacks such as the pore size deviating from the initial setting. However, if the number of particles with a diameter or maximum side of 50 μIn or less exceeds 20, the carbon porous body after firing has the disadvantage that it becomes too dense. In order to increase the pore diameter and porosity r of the carbon porous material, it is preferable to use particles with a large particle size, and conversely, to reduce the pore size, it is preferable to use particles with a small particle size. In order to make the pore size uniform, it is necessary to use several polymer particles. This can be achieved by pre-classifying with a sieve or a sieve to make all the particle sizes uniform, and conversely, making the pore sizes completely non-uniform can be achieved by using particles with a large particle size distribution.

In order to introduce organic molecular particles into all containers, in addition to settling them by gravity, use a vibrator as necessary to increase the strength of the carbon porous material, reduce its size or porosity, etc. , or apply pressure, or both.

Next, it is heated using a t-i placed in a container, a heating oven, etc., to form a continuous porous organic polymer. The heating degree is adjusted to at least 7M, which is at least the softening point of the organic polymer particles -4 and below the melting point, so that the organic polymer particles soften and point adhesion occurs between their surface layers. . If the temperature is too low, the fluidity due to softening, small cracks, or spot adhesion will not occur, and if the temperature is too high, the fluidity due to softening will be poor, so the organic polymer porous material produced will be The disadvantage is that the pores become closed or even disappear.

To make an organic polymer porous body from organic polymer particles using a solvent, first add a solvent that can dissolve the organic polymer particles to 10 wt% of the organic polymer particles, depending on the degree of solubility.
Hereinafter, preferably 5 wt% or less is mixed at high speed using a Henschel mixer or the like using M9. The surface of the organic polymer particles is uniformly wetted using the same method, and then the particles are poured into a container using the same method.

The amount of solvent is such that only the surface layer of the organic polymer particles is dissolved;
It is sufficient to add only the amount necessary to form a continuous organic polymer porous body. If too much is added, the degree of softening of the organic polymer particles becomes too large and the fluidity becomes poor. This is not preferable because the pores of the porous cured polymer material may be closed or even the pores themselves may disappear due to excessive plowing. The liquid containing the solvent put into the container is left alone, but it is also necessary to
．． IL, pressurize, heat, or both.
A solvent-containing polymeric porous material is formed using lV pomace. Thereafter, the solvent is removed from the porous body using a vacuum dryer, a heating dryer, or left to dry for 4 hours to obtain an organic polymer porous body.

Next, the organic polymer porous body obtained by any of the above methods is subjected to an insoluble and infusible treatment. The method of insoluble and infusible treatment is as follows:
A method of heat treatment in a trench at 50 to 300℃ in an oxidizing atmosphere such as air or ozone, a method of heating at 50 to 300℃ in a corrosive gas atmosphere such as ammonia gas or chlorine gas, a method of heating at 50 to 300℃ in an atmosphere of corrosive gas such as ammonia gas or chlorine gas, and a method of heating with a strong acid such as concentrated sulfuric acid. There are methods such as immersion and radiation irradiation. In the present invention, the organic polymer porous body prepared by the above-mentioned method maintains its pore state, and in the next step of carbonization treatment, a strong carbon porous body rich in continuous pores is obtained. Since the insoluble and infusible treatment 7 should be selected in accordance with the properties of the organic polymer particles used, the method of the insoluble and infusible treatment is not particularly limited.

The organic polymer porous body subjected to the insoluble and infusible treatment is then heated at 400°C or higher in an inert atmosphere such as nitrogen and argon.
<< is heated to 700° C. or higher to carbonize. There is no limit to the firing temperature;
It may be heated to about ℃.

In the carbon porous body obtained according to the method of the present invention, most of the pores are continuous, and the porosity and pore diameter can be easily adjusted. The organic polymer particles are firmly fused and welded, and the skeleton is carbonized, so the structure has high strength, and since there are almost no pores, the porosity can easily be maintained at 11. , has advantages such as high thermal shock resistance. Therefore, the carbon porous material produced by the method of the present invention can be used for various filters,
It is useful for catalyst carriers, lightweight structural materials, heat insulating materials, electrodes, chemical adsorbents, planar heating elements, radio wave shielding materials, etc.

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

Example 1 Chlorinated vinyl chloride resin powder with chlorine content of 67% and degree of polymerization of 740 [Nikatemp T-870 manufactured by Nippon Carbide Co., Ltd.
) in a shaking sieve to 48 mesoyu (297μ) -1
Particles having a particle size in the range of 0.00 mesh (149μ) were taken out. Then, the particles were placed into a graphite box having internal dimensions of 100 mm long, IQ mm wide, and 10 mx deep using a vibrator.

Next, it is kept in a heating oven at 180° C. for 20 hours to form a porous body of chlorinated vinyl chloride, and at the same time is subjected to an insoluble and infusible treatment.

Thereafter, under a nitrogen gas atmosphere, temperature is increased from room temperature to 300℃.
"i10℃/h, 300-500'C is 30℃/11.
Firing was performed at a temperature increase rate of 200°C/h from 500°C to 1000°C, and after cooling, the carbon porous body was taken out. Table 1 shows the properties of the porous carbon material.

Example 2 Chlorinated vinyl chloride resin powder with chlorine content of 65 and degree of polymerization of 650 [Nikatemp 1-025 manufactured by Nippon Carbide Co., Ltd.]
] was made using a single screw type molding machine to create a cross section with a diameter of 1514 m.
A linear body was obtained by molding it into a circular shape. Next, this was cut using a pelletizer into pieces with a diameter of 1.5 mm and a height of 1.
．． A whole cylindrical pellet of 5 mm was obtained.

Next, this pellet has a total length of 200 mm, iJ7. Q
After putting it into a graphite box with a depth of 20 mm, it was pressurized at 50 + (9/c〃I) for 1 minute using a hydraulic press. Next, it was held at 150 °C for IO time and then at 180 °C for 3 hours. to form a chlorinated vinyl chloride porous body, followed by 180
The mixture was kept at ℃ for 20 hours to perform insoluble and infusible treatment. Next, in a nitrogen gas atmosphere, from room temperature to 300℃, the temperature is 5℃/1]
, 300-500] dlO℃/h, 500℃-1000
The carbon porous body was fired at a temperature increase rate of 1100 °C (1100 °C), and after cooling, the carbon porous body was taken out.
Shown below.

Example 3 Of the ground tragacanth gum powder, shaking type sieve V
Particles having a particle size in the range of 32 mesh (.500/i) = 200 mesh (74 μ) were taken out using a trowel.

Next, 5 wt % water was uniformly dispersed and mixed in a Kehensiel mixer, and the wet powder was mixed vertically with I Q Q ntm 1'j 1
0 bi71L % depth l Q m, put into a graphite box having inner dimensions of m using Piebreak-2. Next, use a hydraulic press to apply pressure (50 k7,/clrl) for 1 minute, and after removing the roots from the oil press, apply weight to a pressure of 1 kr/cnf. poppy, 5
Hold open for 1 hour adjusted to 0'C, then 11
The mixture was heated to 0° C. for 3 hours to evaporate water to obtain a porous body of silicate gum. Next, add further heat to 180℃ in a microwave oven.
201L? 30'C/h from room temperature to 500℃ under nitrogen gas atmosphere after insoluble insoluble jR11 treatment.
The carbon porous body was fired from 500 to 1000°C at a temperature increase rate of 200°C/11, and after cooling, the carbon porous body was taken out. Table 1 shows various properties of the obtained porous carbon material.

Example 4 Furan initial condensate [Hikufuran vp manufactured by Nizu Kasei Co., Ltd.
-302] (c) A hardening agent was added and heated using three rolls to obtain a composition in the form of a nut having a softening point of 150°C.Then, the stiff material was cooled and crushed in a crusher.Q , l mm -1, o mm were taken out using a shaking sieve.

Next, make this 200 mm long, 20 mm yellow, and 20 mm deep.
Using a vibrator, put it into a graphite box with inner dimensions of [,/ko]. Next, 501 (7/c) with oil LE press machine
After adding nI to LE for 1 minute, it was placed in a 150'CC/) heated oven and kept for 10 hours to obtain a porous furan resin.Then, it was heated to 2001C for 7J and subjected to Motoichi infusibility treatment. . Next, it was fired in a nitrogen atmosphere at a heating rate of 30°C/b from room temperature to 500°C and 200°C/h from 500 to 1000'C, and after cooling, a porous carbon body was obtained.

Table 1 shows various properties of the obtained porous carbon material.

Table 1 Spring Procedural Amendment (Voluntary) November 18, 1981 Kazuinu Wakasugi, Commissioner of the Patent Office 1 Display of the case 1982 Patent Application No. 174023 2 Name of the invention Manufacture of carbon porous body 3 Case of person who makes an amendment Relationship with Patent Applicant Address 23-37 Higashiinui 5-chome Tsuki, Parts Ward, Tokyo Name (595) Mitsubishi Pencil Co., Ltd. 4 Agent Address 104-8-15-10, Ginza, Chuo-ku, Tokyo 104 "8-o, % of particles" on the 14th line from the top of page 8 of the detailed description of the invention in column 6 of the amended specification of contents.
Correct to 90% of particles, j.

Claims (7)

[Claims] (1) Organic polymer particles are placed in a container and the surface of each particle is
Basically, it is a granular sintered body that is made by melting 1* to create point contacts M between particles to form a porous organic polymer, followed by insoluble and infusible treatment and firing in an inert atmosphere. A method for producing a certain porous carbon material. (2) The diameter or maximum side of organic polymer particles is 501 or less, and 90% or more of the particles have a diameter or maximum side of 501
The manufacturing method according to item 1, wherein the length is 1 m or more. (3) Organic polymer particles include particles of thermoplastic resin such as chlorine fL, vinyl chloride resin, polyacrylonitrile resin, polyvinyl alcohol, polyphenylene ether, polyamideimide, and polydivinylbenzene, furan resin, phenol side, and bismaleimide. , particles obtained by curing thermosetting resin monomers such as triazine resin or initial 7 condensates to the extent that they can be thermally deformed or soluble in solvents, gum tragacanth, gum arabic,
Natural polymer particles having a condensed polycyclic aromatic group such as sugars in the basic structure of the molecule, synthetic polymer particles having a condensed polycyclic aromatic group not included in the above basic structure in the basic structure of the molecule, petroleum asphalt, Coal tar pitch, carbonized pitch such as synthetic resin All heat treated at 300 to 500°C and low molecular weight compounds removed with a solventr One or more of the pulverized particles
2. The method for producing a mixture of (4) The organic polymer porous material is made by melting the organic polymer particles described in Items 2 and 3 by heating or using a solvent to melt the surface layer and bond the particles to each other by forming point bonds. The manufacturing method of paragraph 1, which is produced by: (5) The manufacturing method of item 1, wherein the organic polymer porous material is not subjected to insoluble and infusible treatment. (6) The manufacturing method of item 1, wherein the firing is performed by heating to a temperature of 400°C or higher. (7) The organic polymer particles are produced by the carbon production method described in Paragraph 1, in which the coal yield of the polymer material is 5% or more by the manufacturing method described in Paragraphs 5 and 6.