JP2000128652A - Production of activated carbon fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for an activated carbon fiber structure having a large specific surface area in an economically profitable manner. SOLUTION: This method for producing an activated carbon fiber structure comprises coating a thermosetting resin such as a phenolic resin on thermally infusible fibers such as novoloid fibers as the precursor of activated carbon fibers, thermally molding the coated thermally infusible fibers into an arbitrary shape by the use of a heat molding machine to obtain the fiber/thermosetting resin composite article, and subsequently sintering the composite article in the presence of a gas activating agent such as steam or carbon dioxide or a chemical activating agent in a reducing atmosphere such as nitrogen or an inert gas at 600-2,500 deg.C. The produced activated fiber structure has a specific surface area of 1,000-3,000 m2/g and rich profitability.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be used in a wide variety of applications, including deodorants, air purification, purification of tap water and rivers, lake water, solvent recovery, gas separation, electrodes for batteries and capacitors, catalyst support, and molecular sieves. The present invention relates to a method for producing an activated carbon fiber structure that can be used.

2. Description of the Related Art Activated carbon has been used for a long time in the above-mentioned fields of use, especially in the fields of deodorization and water purification.
Powdered or granular activated carbon obtained from bamboo and coal has been used. These are widely used because they are inexpensive, but because they are natural products, there is contamination such as metal content, the quality varies widely, and the surface area per unit weight, which is the main characteristic of activated carbon, the so-called ratio Due to the limited surface area, the range of use is limited for industrial applications or parts of industrial products. recent years,
With the spread of electronic devices and the elimination of environmental problems, high-performance activated carbon has been demanded, and activated carbon fibers having a high adsorption rate and a large specific surface area have been used. However,
With the diversification of needs, the shape of activated carbon fiber is required, and a structure could be obtained by bonding activated carbon fiber with an adhesive such as polyvinyl alcohol. The necessary fine pores are filled and the original performance of the activated carbon fiber is impaired. As a method for resolving this, “Carbon Vol. 35, No. 9” studied by TD Burchell et al.
pp. 1279-1294 (1997) ". This technique uses a pitch-based carbon fiber to obtain an activated carbon structure. In terms of economy, however, the step of firing the carbon fiber and the structure are simplified. The activation firing requires two firing steps, requiring a great deal of time and energy, and is not an economical method, thus maintaining the performance of the activated carbon fiber and economically activating the activated carbon fiber. No method for obtaining the structure has been found.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an activated carbon fiber structure which maintains the characteristics of the activated carbon fiber, reduces the firing step, and economically obtains the activated carbon fiber structure.

Means for Solving the Problems The inventors of the present invention have intensively studied a method of manufacturing an activated carbon fiber structure in order to solve the above-mentioned characteristics and economic disadvantages of the conventional method of manufacturing an activated carbon fiber structure. The present inventors have found a method that can solve the problem, and have reached the present invention. Although the performance of the activated carbon fiber is maintained by the method described in the above-mentioned reference, this manufacturing process requires two firing steps, and is not economical. Because the precursor fiber of the activated carbon fiber is thermoplastic or hot-melt, it loses its fiber structure during heating and firing and carbonizes,
There is an inevitable reason that the carbonized fiber must be treated once so as to withstand activated firing. In the present invention, the activation firing step is performed once, and it has been found that cost and energy consumption can be drastically reduced. That is, it has been found that a fiber that does not melt by firing may be used as a precursor. Specifically, when carbon fibers are usually obtained, infusibilized fibers obtained by performing infusibilization treatment for the same purpose are suitable. Although the infusibilized fiber also has an infusibilizing step, it is clear from the market price that it is significantly more economical than the carbonizing and firing step.
In addition, novoloid fibers that do not even require such infusibilizing treatment are optimal for the purposes of the present invention. As described above, a method for producing an activated carbon fiber structure having a specific surface area of 1,000 to 3,000 m ² / g and rich economic efficiency was found. The present invention relates to a method for producing an activated carbon fiber structure, wherein a thermo-infusible fiber is thermoformed with a thermosetting resin such as a phenol resin in the precursor fiber, activated, fired, and has a large specific surface area.
It is a method for producing an activated carbon fiber structure which is rich in economy.
Hereinafter, the present invention will be described in detail. It is an essential condition that the precursor fiber to be used is inactive at 600 to 1200 ° C. and does not lose the fiber shape, at the temperature conditions during activation and firing. That is, the large specific surface area, which is a characteristic of the fibrous activated carbon, is impaired, and the desired adsorption speed and adsorption amount cannot be obtained. However, in the present invention, it has been found that novoloid fibers, which are essentially heat-insoluble, and acrylic fibers, pitch fibers, and rayon fibers which have been subjected to infusibility treatment are suitable. Acrylic, pitch, and rayon carbon fibers obtained by carbonizing and firing an infusible acrylic fiber, pitch fiber, and rayon fiber can also be used for the purpose of the present invention. It is not economical because a baking step is required. In the present invention, from the viewpoints of economy and quality, novoloid fibers which do not require infusibilizing treatment, that is, can be used as untreated fibers, are most suitable. The thickness and length of the fibers used are not particularly limited. In general, fibers having a diameter of 5 to 40 μm are used. If a large specific surface area is desired, thin fibers are more advantageous. The length can be used from short fiber to long fiber (roving) and is selected according to the purpose. However, in consideration of the primary molding step, a length of 0.1 to 140 mm, preferably 0.1 to 10 mm is suitable. ing. The present invention, the precursor fiber, a solid content of 0.5 to 100 parts by weight of the fiber.
10 parts by weight of phenolic resin, melamine resin, urea resin, resorcinol resin, unsaturated polyester resin, diallyl phthalate resin, bismaleimide resin, polyimide resin, polyamideimide resin, urethane resin, thermosetting resin selected from epoxy resin or these , A mixture of two or more of them is applied and molded into an arbitrary shape by a thermoforming machine to obtain a primary molded product of a fiber / thermosetting resin composite. A phenol resin is preferred because the residual carbon ratio at the time of firing and the resin used for the binder also become activated carbon upon activation and are the same substance as the novoloid fiber of the precursor fiber most suitable for the present invention. If the amount of the binder is less than 0.5 part by weight, the bonding strength is poor, and the molding of the composite before firing is limited. On the other hand, if the amount of the binder is 10 parts by weight or more, the fibers are buried in the resin layer and the properties as a fiber structure are deteriorated. Will be spoiled.
Here, the phenol resin is obtained by a known technique, and is not particularly limited. That is, a known raw material, a catalyst, a water-soluble resol resin, an alcohol-soluble resol resin, a solid resol resin obtained by an apparatus and a method, and an emulsion obtained by emulsifying and dispersing the resol resin with an emulsifier, and curing to 100 parts by weight of a novolak resin. A composition containing 5 to 25 parts by weight of hexamethylenetetramine as an agent, a solution or dispersion of the composition in water, glycols, alcohols, and ketones, and an emulsion emulsified and dispersed with an emulsifier. . The method of curing and molding the phenol resin is performed under known conditions, and is not particularly limited. On the other hand, the fiber / thermosetting resin composite can be obtained by ordinary temperature curing (including low temperature curing). It is molded using an acid-cured phenol resin, a furan resin, an ester-cured phenol resin, and a carbon dioxide-cured phenol resin. The method of obtaining a molded product is generally as follows, for example. Novoloid fiber 1
Solid resole resin powder 0.5 to 10 parts by weight
A weight part is slurried with water and poured into a predetermined mold. After removing the moisture in the mold with a reduced pressure screen, the molded product is removed from the mold and dried at 60 to 80 ° C for 30 to 60 minutes. Thereafter, the mixture is cured and molded at 150 to 200 ° C. for 60 to 180 minutes to obtain a fiber / thermosetting resin composite. At this time, it can be dried and cured in the mold without removing it from the mold. In addition, it is naturally possible to produce a resin-coated fiber by various methods and obtain a molded body by hot press molding, extrusion molding, pull-out molding, transfer molding, or injection molding. Depends on the shape and structure of the The obtained composite is used to obtain an activated carbon fiber structure by a known carbonization activation technique. The atmosphere gas, the activation gas, and the firing activation conditions are not particularly limited. However, in a reducing atmosphere such as nitrogen and helium, neon, argon, xenon, and krypton, water vapor, carbon dioxide is used as an activation gas, or zinc chloride is used. Carbonization is activated using a chemical such as sulfuric acid, potassium hydroxide or the like at a rate of temperature increase of 0.5 to 10 ° C./min. The specific surface area of the activated carbon fiber structure obtained by the present invention is 1
000-3000 m ² / g, deodorant, air freshener,
Tap water, river and lake water purification, solvent recovery, gas separation,
There are a wide variety of applications such as electrodes for batteries and capacitors, catalyst support, and molecular sieves.

Embodiments of the present invention will be described below. [Example 1] Noboro having a fiber diameter of 14 µm and a fiber length of 3 mm
Id fiber (manufactured by Gunei Chemical Industry Co., Ltd., trade name "Kaino
Le, KF-0203) 100g and solid resole type
Knol resin (Gunei Chemical Industry Co., Ltd., PG-412
1) Put 5 g into 1 liter of water, mix well and mix with slurry
I do. The slurry was screened, 100 × 10
Pour into a 0 × 10 mm mold and dehydrate under reduced pressure. Sa
In addition, the mold was placed in a hot air drier at 80 ° C for 60 minutes and dried.
Dry. Gently remove the dried temporary molded body, and
Leave for 120 minutes in a hot air dryer and cure to obtain a composite
You. Place the complex in a 150 mm inner diameter quartz tube and seal
Then, 50 l of nitrogen gas was flowed at a flow rate of 1 l / min.
Replace completely with air. Then nitrogen at 450 ml / min
Heating and sintering is performed at a heating rate of 5 ° C./min while passing gas. Furnace
When the internal temperature reaches 300 ° C, the nitrogen flow rate is 450ml / min.
Switch source gas to gas aerated in pure water to activate
You. When the temperature in the furnace reached 800 ° C., the temperature was maintained for 60 minutes.
After that, stop introducing gas containing water vapor and switch to nitrogen gas.
Replace and hold for an additional 60 minutes with aeration. Finally,
Turn off the heat and let the nitrogen gas pass for about 8 hours at room temperature
To obtain an activated carbon fiber structure. Activated carbon fiber obtained
Structure dimensions 90 × 92 × 8mm, weight 27g, nitrogen
Surface area 1600m obtained by isothermal adsorption method^Two/ G
Met. Example 2 Novo with fiber diameter of 22 μm and fiber length of 10 mm
Lloyd fiber (manufactured by Gunei Chemical Co., Ltd., trade name "Kino
, KF-0510) and the same procedure as in Example 1.
In order, dimensions 91 x 89 x 9 mm, weight 25 g, specific surface area
1680 m^Two/ G of activated carbon fiber structure was obtained. Example 3 Commercially available fiber having a fiber diameter of 10 μm and a fiber length of 10 mm
Procedure similar to Example 1 using pitch-based semi-fired fiber
With dimensions 93 × 91 × 9 mm, weight 31 g, specific surface area 1
360m^Two/ G of activated carbon fiber structure was obtained. Example 4 500 g of phenol, 50% formalin 2
40 g and 5 g of oxalic acid were refluxed at 100 ° C. for 3 hours.
Water at 180 ° C under reduced pressure of 50 torr, unreacted phenol
0.5 g of zinc chloride was added and the mercury method
A novolak resin containing zinc chloride having a softening point of 91 ° C. was obtained. The
Novolak resin is melt spun at 150 ° C and 10 parts by weight
Formaldehyde in an aqueous solution containing 5% hydrogen chloride
Treated at 100 ° C for 4 hours, zinc chloride with fiber diameter of 18μm
The obtained novoloid long fiber was obtained. Example 1 using the fiber
The procedure is the same as that described above, except that the steam as the activation gas is introduced.
Calcined, size 92 × 90 × 8mm, weight 24g, ratio table
Area 1480m^Two/ G of activated carbon fiber structure was obtained. [Example 5] A fiber / thermosetting resin composite of Example 1 was obtained.
In the process, the fiber diameter is 14 μm and the fiber length is 3 mm.
Resole type phenol tree for 100g of void fiber
Fat (Gunei Chemical Industry Co., Ltd., trade name PL-263)
8) 10 g, 40 parts by weight p-toluenesulfonic acid aqueous solution
Add 3g, immediately fill the mold and leave it for 3 hours
Then, the resultant was removed from the mold to obtain a composite. Subsequent steps are the same as those of the first embodiment
By the same procedure, dimensions 92 × 90 × 9mm, weight 23g,
Specific surface area 1520 m^Two/ G of activated carbon fiber structure
Was. Example 6 A fiber / thermosetting resin composite of Example 1 was obtained.
In the process, the fiber diameter is 14 μm and the fiber length is 3 mm.
Commercially available as binder for 100 g of void fiber
6g of phenol novolak epoxy resin and hardener
Using the same procedure as in Example 1 using 4 g, dimensions 90 × 92
× 8mm, weight 21g, specific surface area 1580m^Two/ G activity
A charcoal fiber structure was obtained. [Embodiment 7] In the activation step of Embodiment 1, the ambient temperature
Reaches 300 ° C, the flow rate is 450 ml / min.
By introducing carbon oxide, the same procedure as in Example 1 was carried out to obtain a dimension 93
× 92 × 9mm, weight 26g, m of specific surface area 1620^Two
/ G of activated carbon fiber structure was obtained. Example 8 In the carbonization and activation process of Example 1, 80
After stopping the introduction of the activation gas at 0 ° C., the temperature is further increased at 5 ° C./min.
Continue heating and heat to 2000 ° C. Others are the same as Example 1.
With the same procedure, dimensions 87 x 88 x 8 mm, weight 20 g, ratio
Surface area 1580m ^Two/ G X-ray diffraction 2θ = 26.5 °
A graphitic activated carbon structure with absorption was obtained. [Example 9]
To 100 parts by weight of KF-0203 shown in Example 1
And uniformly apply 0.5 parts by weight of potassium hydroxide on a solid basis.
Cloth, and in the same procedure as in Example 1, dimensions 90 × 88 × 8 m
m, weight 23 g, specific surface area 1560 m^Two/ G of activated carbon
A fiber structure was obtained. [Comparative Example] Activated carbon fiber with a fiber diameter of 11 μm and a fiber length of 6 mm
Wei (Kainor Activated Carbon A, manufactured by Nippon Kainol Co., Ltd.)
CF-1606-15, specific surface area 1580m^Two/ G) 1
200 g of polystyrene having a weight average molecular weight of 10,000
Example 1
Molded in the same procedure as 1 and dimensions 98 × 97 × 10 mm,
Weight 101g, specific surface area 739m^Two/ G activated carbon fiber structure
A structure was obtained. Table 1 shows the above results.

[Table 1]

According to the present invention, the activated carbon fiber structure can be prepared without impairing the properties of the activated carbon fiber, that is, the high specific surface area.
And made it possible to obtain it in an economical way. The activated carbon fiber structure is applied as a member in a wide range of industrial fields.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Masaru Kimura 700 Shukudaidaicho, Takasaki City, Gunma Prefecture Inside Gunei Chemical Industry Co., Ltd. In-house F-term (reference) 4G032 AA13 AA14 AA52 AA58 BA00 BA05 GA12

Claims (12)

[Claims] The present invention relates to 100 parts by weight of novoloid fiber as a precursor fiber and a solid content of 0.5 as a primary molding binder.
Activated carbon fiber obtained by uniformly applying 10 to 10 parts by weight of a thermosetting resin, thermoforming into an arbitrary shape, and firing at a firing temperature of 600 to 1200 ° C. in a nitrogen atmosphere while using steam as an activation gas. The method of manufacturing the structure. 2. The activated carbon fiber structure according to claim 1, wherein the precursor fiber is an infusibilized acrylic fiber, pitch fiber, or rayon fiber. Manufacturing method. 3. The novoloid fiber according to claim 1, wherein the novoloid fiber contains 0.1 to 10 parts by weight of zinc chloride per 100 parts by weight of the novoloid fiber. 3. The method for producing an activated carbon fiber structure according to item 1. 4. The method for producing an activated carbon fiber structure according to claim 1, wherein the novoloid fiber is a short fiber having a fiber length of 0.1 to 140 mm. 5. The primary molding binder according to claim 1, wherein
The primary molding binder is a water-soluble resole resin, an alcohol-soluble resole resin, a solid resole resin, an emulsion in which the resole resin is emulsified and dispersed with an emulsifier, and hexamethylenetetramine 5 to 25 as a curing agent for 100 parts by weight of a novolak resin. Using a composition containing parts by weight, or a solution or dispersion of the composition dissolved in water, glycols, alcohols, and ketones, and an emulsion emulsified and dispersed with an emulsifier, and molding by thermosetting. The method for producing an activated carbon fiber structure according to any one of claims 1 to 4, wherein 6. The primary molding binder according to claim 1, wherein:
The method for producing an activated carbon fiber structure according to any one of claims 1 to 5, wherein the primary molding binder is formed by curing at room temperature using an acid-cured phenol resin and a furan resin, an ester-cured phenol resin, and a carbon dioxide-cured phenol resin. . 7. The primary molding binder according to claim 1, wherein:
7. The binder according to claim 1, wherein the binder is a melamine resin, a urea resin, a resorcin resin, an unsaturated polyester resin, a diacryl phthalate resin, a bismaleimide resin, a polyimide resin, a polyamideimide resin, a urethane resin, or an epoxy resin. A method for producing an activated carbon fiber structure. 8. The primary molding binder according to claim 1, wherein:
The method for producing an activated carbon fiber structure according to any one of claims 1 to 7, wherein the binder is a mixture of two or more binders among the binders according to claim 5 and claim 7. 9. The activated carbon fiber structure according to claim 1, wherein the activation gas is carbon dioxide. 10. The activated carbon fiber structure according to claim 1, wherein the activation method is a chemical activation using zinc chloride, sulfuric acid and potassium hydroxide. Production method. 11. The method for producing an activated carbon fiber structure according to claim 1, wherein said atmosphere gas is helium, neon, argon, xenon, or krypton. 12. The sintering step according to claim 1, wherein
The method for producing a graphitic activated carbon structure according to any one of claims 1 to 11, wherein after the activation and firing at 1200 ° C, the introduction of the activation gas is stopped and the firing is further performed at 1200 to 2500 ° C.