JPS62283866A - Manufacture of active carbon formed body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 5. Detailed Description of the Invention (Industrial Field of Application) For example, the present invention relates to a method for manufacturing an activated carbon molded product used for a dissolving medium carrier such as a battery electrode, a filter, and the like. My goal is,
The goal is to allow activated carbon to fully demonstrate its functions such as adsorption and catalytic abilities.

Activated carbon molded articles are manufactured by kneading the organic binder with activated carbon and other materials used as necessary, and subjecting the mixture to a firing treatment. The fine pores that are naturally formed when the organic binder is carbonized by firing are used as gas passages to the activated carbon that is dispersed therein.

However, it is difficult to obtain a sufficient activated carbon function, probably because the surface of the activated carbon is covered with a carbon skeleton.

Therefore, the applicant of the present application previously filed an application to greatly improve this problem by using activated carbon coated in advance with a depolymerizable organic substance (Japanese Unexamined Patent Publication No. 60-2046).
No. 10).

The present invention makes it possible to achieve even greater effects.

(Means for Solving the Problems) The present invention uses an organic binder that carbonizes when fired and activated carbon as at least the main materials, and after cross-wiring, fires to produce an activated carbon molded product.

The activated carbon before kneading is impregnated in advance with a sublimating substance that starts to sublimate at a temperature below the temperature at which the organic binder starts to decompose and carbonize, and the surface is further impregnated with air at a temperature above the temperature at which the organic binder starts to decompose and carbonize. The gist of the present invention is a method for producing an activated carbon molded article, which is characterized by being coated with a depolymerizable organic substance that is dispersed in the activated carbon.

The details will be explained below.

There are a variety of organic binders to choose from, including natural and synthetic resins, rubber, thermosetting precondensates, pitch, tar, and asphalt; examples include styrene resin, acrylic resin, urea resin, and melamine resin. , polyester resin, furan resin, polyvinyl alcohol, polyacrylamide, butyl rubber, chlorinated polyvinyl chloride.

Examples include chlorinated polyethylene and polyvinyl chloride, and they can be used alone or in combination of two or more.

As activated carbon, it can be used as appropriate regardless of raw materials, manufacturing method, etc., and the particle size is not particularly limited. however.

If the particle size is too large, it may cause a loss in the strength of the molded product, so it is preferable to use particles with a particle size of 100 μm or less.

As the sublimable substance to be impregnated into the activated carbon, one is selected that starts to sublimate at a temperature below the temperature at which decomposition and carbonization of the organic binder starts. - Examples are naphthalene, camphor, baladichlorobenzene, iodine, etc.

As a method for impregnating activated carbon with a sublimable substance, generally known methods such as immersing activated carbon in a solution of a sublimable substance dissolved in a solvent, heating immersion, or vacuum impregnation can be used.

As the depolymerizable organic substance that coats the surface of the activated carbon, one is selected that vaporizes at a temperature higher than the temperature at which the organic binder starts to decompose and carbonize. - Examples are polyethylene, polypropylene, polybutadiene.

Polyisobutylene, polystyrene, nylon.

These include polymethmethylstyrene, polymethyl methacrylate, polyethyl ethacrylate, pyri-α-toiterostyrene, and the like. There are also depolymerized types of natural rubber. Particularly preferred among these is polymethyl methacrylate, which exhibits an extremely high degree of depolymerization.

To coat the surface of activated carbon with a depolymerized organic substance, various methods known for producing microcapsules can be adopted, such as emulsion or suspension methods, powder bed methods, etc., but the easiest method is considered to be , kneading, using plasticizers, solvents, etc. as necessary. Another advantage is that the relative proportions of usage can be easily changed.

The activated carbon thus obtained is kneaded with an organic binder and optionally used stabilizers, solvents, graphite, etc. using a kneader with 23 rolls or the like. This is formed into a desired shape such as a plate, two cylinders, or a honeycomb shape, and further dried if necessary.

The organic binder is carbonized by heat treatment of firing.

At this time, when the sublimable substance impregnated into the activated carbon and the depolymerizable organic substance coated on the surface are diffused.

A rapid temperature increase rate may cause cracking or swelling of the molded product, so it is desirable to decide the temperature increase rate with due consideration. For example, when polyvinyl chloride is used as an organic binder, it varies depending on the grade, etc.
It is recommended that the temperature increase rate be 5°C or 2°C per minute in the range from 30°C to 300°C. Further, the firing can be carried out in an appropriate non-oxidizing atmosphere such as an inert gas atmosphere, a reducing atmosphere, or a vacuum atmosphere.2 Usually,
The maximum temperature is about 600°C to 900°C.

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

(Function) Since the sublimable substance impregnated into the activated carbon starts sublimating at a temperature below the temperature at which the organic binder starts to decompose and carbonize, it easily evaporates even if it is impregnated to the minute pores. In this state, the surface of the activated carbon is coated with a depolymerizable organic substance that evaporates at a temperature higher than the temperature at which decomposition and carbonization of the organic binder starts. In other words, empty pores, especially micropores, are secured without being blocked by the carbide of the organic binder. and.

The gas generated by the decomposition of the depolymerized organic matter is vented, leaving a path as a continuous vent. At this time, it is unlikely that depolymerized organic substances remain in the activated carbon pores. Moreover, this communicating hole is connected to the inside of the activated carbon. This is what the inventor of the present invention conjectures.

(Example) Hereinafter, parts simply refer to parts by weight.

[Example 1] (1) Preparation of activated carbon coated with a depolymerizable organic substance impregnated with a sublimable substance.
50 parts (50 mesosh or less) was immersed and left to stand for about 30 minutes to fully impregnate the solution into the activated carbon. After quickly drying the activated carbon taken out from the solution to remove methyl ethyl ketone,
Polymethyl methacrylate) and methyl ethyl ketone were immersed in a solution prepared in a ratio of 1=2.

After being left for about 10 minutes, it was taken out and the activated carbon surface was coated with Acrysilab 5Y-103.

I got 75 copies.

(2) Manufacture of activated carbon molded product Activated carbon prepared in (1) 75 parts Polyvinyl chloride resin 30 parts Dioctyl phthalate (plasticizer) 15 parts Stearate (stabilizer)
Part 2 graphite
20 parts methyl ethyl ketone
20 parts of the above blend was kneaded in a kneader for 15 minutes and then extruded to obtain a rod-shaped molded product with a diameter of about 1 mm.

This was heated in air from room temperature to 300°C at a rate of temperature increase of about 2°C/min, and then fired in a closed container at 850°C for 1 hour to obtain an activated carbon molded article.

[Example 2] In Example 1, instead of white charcoal Y, powdered carbon PW (powdered activated carbon manufactured by Kuraray Chemical ■: particle size of 200 mm or less) was used.
Everything was the same as in Example 1 except that .

[Example 3] Everything was the same as in Example 1 except that di-camphor was used in place of naphthalene.

[Comparative Examples 1 and 2] In Example 1 (2) and 2 (2), instead of 75 parts of activated carbon impregnated with a sublimable substance and coated with a depolymerizable organic substance, activated carbon impregnated with a sublimable substance (before treatment) was used. The same procedure as in Examples 1 and 2 was carried out except that 50 parts of activated carbon was used.

[Comparative Examples 3 and 4] In Example 1 (2) and 2 (2), instead of 75 parts of activated carbon impregnated with a sublimable substance and coated with a depolymerizable organic substance, activated carbon coated with a depolymerizable organic substance (before treatment) was used. Everything was the same as in Example 1.2 except that 50 parts of activated carbon) was used.

[Comparative Examples 5 and 6] In Examples 1-(2) and 2-(2), 50 parts of activated carbon without any treatment was used instead of 75 parts of activated carbon impregnated with a sublimable substance and coated with a depolymerizable organic substance. All procedures were carried out in the same manner as in Examples 1 and 2.

(Effect of the invention) Table 1 shows the evaluation results obtained on each side.

In addition, 1 strength is based on JIS S 6005, specific surface area B
Measured by ET method.

Table 1 As can be seen from Table 1, according to the present invention, an activated carbon molded product having excellent activated carbon function can be obtained.

Claims (1)

[Claims] When producing an activated carbon molded product by using at least an organic binder that carbonizes by firing and activated carbon as the main materials and firing after kneading, the activated carbon before kneading is heated to a temperature below the temperature at which the organic binder starts to decompose and carbonize. An activated carbon molded article characterized in that it has been impregnated in advance with a sublimable substance that starts to sublimate at , and its surface is further coated with a depolymerizable organic substance that evaporates at a temperature higher than the temperature at which decomposition and carbonization of the organic binder starts. Production method.