JPH07100635B2 - Method for manufacturing activated carbon molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a method for producing an activated carbon molded product that is required to have an activated carbon function and gas permeability, for example, used for electrodes, filters, catalyst carriers of air batteries.

(Prior art and its problems) Generally, an organic binder that is carbonized by firing such as various synthetic resins is kneaded with activated carbon and other materials used as necessary, and firing treatment is performed to produce an activated carbon molded product. are doing. It is used as a gas passage to the activated carbon in which the fine pores that are naturally formed during the carbonization of the organic binder by firing are dispersedly contained.

However, it seems that the surface of the activated carbon is covered with a carbon skeleton, but it is difficult to obtain a sufficient activated carbon function.

Therefore, the applicant of the present application has previously filed an application to greatly improve this problem by using activated carbon precoated with a depolymerizable organic substance (Japanese Patent Laid-Open No. 60-204610).
issue).

The present invention has made it possible to achieve a greater effect.

(Means for Solving Problems) In the present invention, an organic binder that carbonizes by firing and activated carbon are used as at least main materials, and after kneading and molding, firing is performed to produce an activated carbon molded product, before kneading. The method for producing an activated carbon molded article is characterized in that the activated carbon is adhered to the outer surface of a substance that is diffused or consumed at a temperature at which the organic binder starts to decompose and carbonize, and then kneaded. .

The details will be described below.

As the organic binder, there are various kinds of selection objects such as natural and synthetic resins, rubber, thermosetting initial condensate, pitch, tar, and asphalt. As an example, styrene resin, acrylic resin, urea resin, melamine resin, Polyester resin, furan resin, polyvinyl alcohol, polyacrylamide, butyl rubber, chlorinated polyvinyl chloride, chlorinated polyethylene, polyvinyl chloride, etc.
Alternatively, two or more kinds can be used in combination.

Activated carbon can be appropriately used irrespective of the raw material and the manufacturing method, but the particle size is preferably 100 μm or less because it has a relationship with the particle size of the substance that adheres the activated carbon to the outer surface.

As the substance for attaching the activated carbon to the outer surface, it is selected that the organic binder diffuses or is consumed at a temperature higher than the temperature at which the decomposition and carbonization starts. Inorganic substances include various inorganic salts such as carbonates, nitrates, sulfates and phosphates, and organic substances include polyethylene, polypropylene, polybutadiene,
Examples include depolymerizable organic substances such as polyisobutylene, polystyrene, polymethamethystyrene, polymethylmethacrylate, ethyl polyethacrylate, polyacrylic acid ester, poly-α-deuterostyrene, and nylon.
In view of the relationship with the particle size of the activated carbon attached to the outer surface, air diffusion, and easiness of consumption, polymethylmethacrylate, polyacrylic acid ester, nylon, etc. are preferable. Among them, polymethylmethacrylate beads are This is an example of a particularly preferable one in view of ease of selection of particle size, decomposition temperature, strength and the like. The particle size of the substance is preferably about 10 to 100 times the particle size of activated carbon. However, if the particle size is too large, it may cause the strength of the molded product to be impaired. Further, it is preferable that the amount of the substance remaining after firing is as small as possible, and at the same time, it is preferable that vaporization and consumption do not occur so much up to about 300 ° C. This is because the volume shrinkage of the molded product during firing almost completes at about 300 ° C.

As a method for attaching activated carbon to the outer surface of the substance, a general method using a ball mill, a sand mill, a mixer, a roll mill, a kneader or the like can be used, but it is preferable that the shearing force is not so high. This is because if the shearing force is too high, the particle size ratio between the activated carbon and the substance may significantly change due to pulverization. By the way, if a hybridization system is used, activated carbon can be uniformly attached to the outer surface of the substance without shearing force.

The substance with activated carbon attached to the outer surface in this manner is kneaded with a kneader, a three-roll mill, etc. together with an organic binder, a stabilizer, a solvent, graphite, etc., which are optionally used.

This is formed into a desired shape such as a plate shape, a column shape, or a honeycomb shape, and if necessary, dried and then heat-treated for firing to carbonize the organic binder. At this time, when the substance with activated carbon attached to the outer surface is vaporized and consumed, a rapid heating rate may cause cracking or swelling of the molded product. It is desirable to decide. In addition, firing can be performed in an appropriate non-oxidizing atmosphere such as an inert gas atmosphere, a reducing atmosphere, or a vacuum atmosphere.
The maximum temperature is about 600 ℃ -900 ℃.

After firing, activation treatment or the like is further performed as necessary to obtain an activated carbon molded product.

(Function) The substance having activated carbon adhered to the outer surface is present even after kneading and molding, but in the heat treatment stage, vaporization or consumption starts at a temperature higher than the temperature at which decomposition and carbonization of the organic binder starts. As a result, the vent passage of gas remains as a communicating hole, and the diffused or exhausted portion of the substance remains as a relatively large space such as a cavity around which activated carbon is arranged.

(Example) In the following, "parts" means "parts by weight".

[Example 1] (1) Preparation of a substance having activated carbon adhered to the outer surface Kuraray Coal PK (powdered activated carbon manufactured by Kuraray Chemical Co., Ltd .: particle size)
50 parts of 200 mesh or less) and 20 parts of polymethylmethacrylate beads (manufactured by Mitsubishi Rayon Co., Ltd .: spheres having a particle size of 0.5 to 1.0 mm) were mixed by a ball mill for about 1 hour.

(2) Manufacture of activated carbon moldings Material with activated carbon prepared in (1) attached to the outer surface 70 parts Polyvinyl chloride resin 30 parts Dioctyl phthalate (plasticizer) 15 parts Stearate (stabilizer) 2 parts Graphite 10 Parts Methyl ethyl ketone (solvent) 30 parts The above mixture was kneaded with a kneader for 15 minutes and then extrusion-molded to obtain a rod-shaped molded product having a diameter of about 5 mm. Room temperature from room temperature to 300
After heating up to 2 ° C at a heating rate of about 2 ° C / min, calcination was carried out at 850 ° C for 1 hour in a closed container to obtain an activated carbon molded product.

[Example 2] In Example 1, except that acrylic bead polymer (polyacrylate ester manufactured by Mitsubishi Rayon Co., Ltd .: sphere divided to a particle size of 0.5 to 1.0 mm) was used in place of the polymethylmethacrylate beads. All were the same as in Example 1.

[Comparative Examples 1 and 2] Comparative Examples 1 and 2 were the same as Examples 1 and 2 except that activated carbon, polymethyl methacrylate beads, and acrylic bead polymers were separately used without the treatment (1). I did the same.

[Comparative Example 3] The same procedure as in Example 1 was carried out except that, in (2) of Example 1, 50 parts of activated carbon which was not treated at all was used in place of 70 parts of the substance having activated carbon adhered to the outer surface.

(Effects of the Invention) Table 1 shows the evaluation results of the products obtained in each example.
The specific surface area was measured by the BET method, and the adsorption capacity was measured by decolorizing methylene blue according to JIS K1470.

As can be seen from Table-1, according to the present invention, it is possible to obtain an activated carbon molded product having an excellent activated carbon function.

Claims (1)

[Claims] 1. An activated carbon before kneading is used to produce an activated carbon molded article by kneading, molding and firing after using an organic binding agent carbonized by firing and activated carbon as at least main materials. A method for producing an activated carbon molded article, which comprises preliminarily adhering to an outer surface of a substance which is diffused or exhausted at a temperature equal to or higher than the temperature at which decomposition carbonization starts and then kneading.