JP2003020517A - Resin composition for compound fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for obtaining a compound fiber suitable as a precursor of an ultrafine carbon fiber, the ultrafine carbon fiber obtained by carbonizing the compound fiber and an ultrafine active carbon fiber prepared by activating the carbon fiber. SOLUTION: This resin composition for the compound fiber comprises 10-50 mass% of a phenol resin and 90-50 mass% of a polypropylene having 10-100 g/10 min melt index(MI) under conditions of 230 deg.C temperature and 21.8 N load. The resin composition for the compound fiber comprises 10-50 mass% of the phenol resin and 90-50 mass% of a polyethylene having >=0.940 g/cm<3> density and 10-30 g/10 min MI measured under conditions of 190 deg.C and 21.18 N load. The compound fiber is prepared by spinning these resin compositions and has 5-100 μm average fiber diameter. The ultrafine carbon fiber is obtained by carbonizing the compound fiber and has >=0.5 μm average fiber diameter. The ultrafine active carbon fiber is prepared by activating the carbon fiber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition for conjugate fiber, a conjugate fiber comprising the resin composition, an ultrafine carbon fiber obtained by carbonizing the conjugate fiber, and an ultrafine activity obtained by activating the carbon fiber. It relates to carbon fibers and to the shaped objects of these fibers.

[0002]

2. Description of the Related Art Phenolic carbon fibers obtained by carbonizing phenol resin fibers and activated carbon fibers obtained by activating the same are excellent in heat resistance, chemical resistance, conductivity, etc. Wide range of fillers, heat insulators, sealants, automobile canisters, flue gas desulfurization adsorbents, dioxin adsorbents, charge double layer capacitors, lithium batteries, charge double layer capacitors and fuel cell electrode materials, separators, etc. It is used in the field and is expected to be used further. One of the methods for further improving the performance of such carbon fibers is to make the fibers extremely fine. When considering electrode materials as an application development of ultrafine carbon fibers, it can be expected as a material with higher performance by further activating ultrafine carbon fibers having a large surface area (specific surface area) per unit weight into ultrafine activated carbon fibers. . Also, when considering a filler for composite materials as an application development of ultra-fine carbon fiber, not only a highly rigid composite material can be obtained, but also a high-rigidity material that can be applied to thin-walled molded products, Since many conductive paths are formed, a highly conductive material can be obtained.

In order to produce a phenol resin ultrafine carbon fiber, it is necessary to produce an ultrafine phenol resin fiber.
As a method of making a very fine phenol resin fiber by using the conventional melt spinning technique, a resin discharge port in a spinneret is made small in diameter, a method of melt spinning a phenol resin fiber at an increased spinning speed, a phenol resin and other A method of extruding a resin and a special spinneret to melt-spin the sea-island type composite fiber, and mechanically removing only the resin of the sea component, or using a solvent etc. to take out only the phenol resin of the island component. And so on. Then, ultrafine carbon fibers are produced by carbonizing these precursor fibers.

However, the phenol resin, which is a raw material for the phenol resin fiber, is an amorphous resin and has a low degree of polymerization, so that spinning is difficult. Further, the obtained phenol resin fiber has a problem that the strength and the elongation are insufficient and it is extremely brittle. Therefore, the method of using a spinneret having a small diameter and increasing the spinning speed has a problem that productivity is extremely lowered. In addition, since the discharged phenol resin is cooled and solidified at a position very close to the spinneret, the stretching effect during spinning can hardly be expected,
The fiber diameter was limited to about 12 μm. Further, since the phenol resin is brittle, it cannot be stretched after spinning, and it is practically impossible to make the phenol resin fiber fine by stretching. Further, when a special die is used, the shape of the die becomes extremely complicated, resulting in a marked drop in productivity, and it has been impossible to obtain a phenol resin fiber having a fiber diameter of 10 μm or less. Further, in the method of removing sea components with a solvent or the like, a large amount of solvent is required, which causes a problem that work environment is significantly deteriorated. A method for obtaining a phenolic ultrafine carbon fiber is disclosed in JP-A-2001-7322.
No. 6, gazette, etc., but when simply compounding a phenol resin and a polyethylene resin,
There is a problem that the ultrafine carbon fibers finally obtained will be shrunk or the fibers will be fused.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a resin composition for obtaining a composite fiber suitable as a precursor of an ultrafine carbon fiber, and by carbonizing the composite fiber It is an object of the present invention to provide an ultrafine carbon fiber obtained, an ultrafine activated carbon fiber obtained by activating the carbon fiber, and a shaped article obtained by shaping these fibers.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a resin resin obtained by mixing a phenol resin and a specific polypropylene or a specific polyethylene in a specific ratio. The composition is suitable as a resin composition for a composite fiber, and a composite fiber fiber obtained by spinning the resin composition is suitable as a precursor of an ultrafine carbon fiber, and carbonizing the composite fiber. It was found that an ultrafine carbon fiber having an average fiber diameter of 0.5 μm or less was obtained by the method, and an ultrafine activated carbon fiber was obtained by activating the ultrafine carbon fiber. The present invention has been completed based on such findings. That is, the present invention uses 10 to 50% by mass of a phenol resin and a temperature of 2
A resin composition for a composite fiber, which comprises 90 to 50 mass% of polypropylene having an MI (melt index) measured at 30 ° C. and a load of 2.18 N of 10 to 100 g / 10 min,
Phenolic resin 10 to 50 mass% and density 0.940 g
/ Cm ³ or more, temperature 190 ° C., MI (melt index) measured under conditions of load 21.18 N is 10 to 30 g /
Resin composition for composite fiber consisting of 90 to 50% by mass of polyethylene for 10 minutes, composite fiber having an average fiber diameter of 5 to 100 μm obtained by spinning these resin compositions,
An ultrafine carbon fiber having an average fiber diameter of 0.5 μm or less obtained by carbonizing the composite fiber, and an ultrafine activated carbon fiber obtained by activating the ultrafine carbon fiber are provided. The present invention also provides a shaped article obtained by shaping these fibers.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The phenol resin used in the present invention is obtained by subjecting phenols and aldehydes to a condensation polymerization reaction in the presence of a reaction catalyst. As the phenols, for example,
Phenol, o-cresol, m-cresol, p-cresol, bisphenol-A, 2,3-xylenol, 3,5-xylenol, p-tertiarybutylphenol, resorcinol and the like can be mentioned. Examples of aldehydes include formaldehyde, paraformaldehyde, hexamethylenetetramine, furfural, benzaldehyde, salicylaldehyde and the like.

The molar ratio of aldehydes to phenols is
Although not particularly limited, it is preferably 0.6: 1 to 0.86:
It is 1. Examples of the reaction catalyst include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as oxalic acid and paratoluenesulfonic acid, oxycarboxylic acids such as citric acid and tartaric acid, and zinc compounds such as zinc chloride and zinc acetate. . The phenol resin used in the present invention is not limited to a linear molecule, and may be a partially branched molecule. Also, its composition is
It may be composed of a single phenol resin or may be a mixture of two or more components in an arbitrary ratio. The molecular weight of the phenol resin is also not particularly limited, but in order to be meltable in a temperature range suitable for melt spinning and have a viscosity range suitable for melt spinning, the average molecular weight thereof is in the range of 500 to 50,000. It is preferable. The softening point of the phenol resin is not particularly limited, but is preferably 90 ° C or higher, and particularly preferably 120 to 130 ° C. In the present invention, a novolac type phenol resin having a softening point of 90 ° C. or higher is preferable.

As the polypropylene used in the present invention,
Examples include homopolypropylene, block polypropylene and random polypropylene. Here, homopolypropylene is a resin obtained by polymerizing propylene alone,
Block polypropylene and random polypropylene are copolymers of propylene and other comonomers,
As other comonomers, ethylene and olefins having 4 to 6 carbon atoms (1-butene, 1-pentene, 1-hexene, etc.) can be used. As polyethylene, a homopolymer of ethylene such as high-pressure low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene, or a copolymer of ethylene and α-olefin; ethylene / vinyl acetate copolymer Examples thereof include copolymers of ethylene and other vinyl monomers such as polymers. Examples of the α-olefin copolymerized with ethylene include propylene, 1-butene, and 4-methyl-1.
-Pentene, 1-hexene, 1-octene and the like. Examples of other vinyl monomers include vinyl esters such as vinyl acetate; (meth) acrylic acid, (meth)
Examples thereof include (meth) acrylic acid such as methyl acrylate, ethyl (meth) acrylate, and n-butyl (meth) acrylate, and alkyl esters thereof. In the present invention, the MI (melt index) measured under the conditions of a temperature of 230 ° C. and a load of 21.18 N is 10 to 100 g / 10.
Min polypropylene, density more than 0.940, temperature 190
Polyethylene having an MI (melt index) of 10 to 30 g / 10 min measured under the conditions of a temperature of 21 ° C. and a load of 21.18 N is used. When the MI of polypropylene is less than 10 g / 10 minutes, the islands of the phenol resin in the sea-island structure are not formed well when the composite fiber described below is produced, and the spinnability and the like are significantly reduced. Also, MI is 100g / 1
If it exceeds 0 minutes, the sea-island structure with the phenol resin becomes non-uniform, so that the spinnability is remarkably reduced, and stable fiberization cannot be achieved. Further, when polyethylene is used, if the density is less than 0.940 g / cm ³ , the carbon fiber will shrink in the step of carbonizing the composite fiber. The density of polyethylene is preferably 0.940 to 0.968 g / cm ^3.
Is. If the MI of polyethylene is less than 10 g / 10 minutes, the fibers will be broken when the composite fiber is spun, making it difficult to perform good spinning. Further, when the MI of polyethylene exceeds 30 g / 10 minutes, phase separation between the phenol resin and polyethylene occurs, and the fibers are cut, making it difficult to perform good spinning.

In the present invention, the mixing ratio of phenol resin and polypropylene or polyethylene is 10 to 50% by mass of phenol resin and 90 to 50% by mass of polypropylene or polyethylene, but preferably 10 to 30% by mass of phenol resin. , Polypropylene or polyethylene is 90 to 70% by mass. If the phenol resin is less than 10% by mass, sufficient phenol-based ultrafine carbon fibers cannot be obtained, and if the phenol resin exceeds 50% by mass,
Since it becomes impossible to obtain a good sea-island structure, the spinnability is reduced and the carbon fiber obtained by carbonization has a non-uniform structure.

If desired, various additives may be added to the resin composition for conjugate fibers of the present invention. Examples of the additives include antioxidants, ultraviolet absorbers, pigments and dyes. The resin composition for conjugate fibers of the present invention can be obtained by mixing and kneading a phenol resin and polypropylene or polyethylene by a known method. As the kneading device, a known device can be used, and examples thereof include an extruder-type kneading machine, a mixing roll, a Banbury mixer, and a high-speed biaxial continuous mixer. The kneading time of the phenol resin and polypropylene or polyethylene is appropriately selected depending on the amount of the resin, the mixing ratio of the phenol resin and polypropylene or polyethylene, and the target fiber diameter of the phenol resin as the island component, and is not particularly limited. The kneading temperature of the phenol resin and polypropylene or polyethylene is not particularly limited, but is preferably in the range of 180 to 280 ° C, more preferably 200 to 260 ° C.

The resin composition thus obtained is extruded from the spinneret in a molten state and melt-spun,
A sea-island type composite fiber in which the sea component is a polyolefin resin and the island component is a phenol resin can be obtained.
Furthermore, by curing the island component phenol resin, a cured composite fiber can be obtained. Next, the hardened composite fiber is carbonized in an inert atmosphere to obtain a phenolic ultrafine carbon fiber. By subjecting this ultrafine carbon fiber to activation treatment, an ultrafine activated carbon fiber can be obtained. In the present invention, the phenolic ultrafine carbon fiber can be obtained by simply carbonizing the composite fiber, so that the working environment is significantly improved,
It can be easily manufactured.

The temperature during melt spinning is not particularly limited, but is preferably in the range of 150 to 300 ° C, more preferably 160 to 250 ° C. The hole diameter of the spinneret is appropriately selected depending on the fiber diameter of the target conjugate fiber and is not particularly limited, but preferably 0.1 to 5.0 m.
m, and more preferably 0.2 to 4.0 mm. As the melting method, a known method can be used, and examples thereof include an extruder method and a melter method. The heating method is also
Any of an electric heating method, a steam heating method and a heating medium heating method is possible. The spinning speed is not particularly limited, but is preferably 50 to 6,000 m / min, more preferably 200.
~ 4,000 m / min. In the melt spinning, a phenol resin and polyethylene may be melt-kneaded and then directly spun in a molten state. Alternatively, the phenol resin and polyethylene may be kneaded and pelletized once, and then the pellet may be melt-spun. The curing treatment of the phenol resin is performed by a known method, and examples thereof include a method of curing the phenol resin with an aldehyde in the presence of a crosslinking catalyst. Examples of the crosslinking catalyst include acidic catalysts such as hydrochloric acid, sulfuric acid, nitric acid, oxalic acid and p-toluenesulfonic acid, and basic catalysts such as ammonia, calcium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide and sodium carbonate. Can be mentioned. Examples of aldehydes include formaldehyde, paraformaldehyde, benzaldehyde, furfural and the like.

The reaction conditions during the curing treatment are appropriately selected depending on the type and amount of the crosslinking catalyst and aldehydes used, the reaction method and the like. For example, when hydrochloric acid is used as the crosslinking catalyst and formaldehyde is used as the aldehydes, hydrochloric acid is 5 to 2
Using an aqueous solution of 0 mass% and formaldehyde of 5 to 20 mass%, the treatment is performed at 60 to 110 ° C for 3 to 30 hours. In this way, a composite fiber having an average fiber diameter of 5 to 100 μm can be obtained. By carbonizing such a composite fiber, an ultrafine carbon fiber having an average fiber diameter of 0.5 μm or less can be obtained. Carbonization of the composite fiber is performed by a known method. Examples of the inert gas used for carbonization include nitrogen and argon. The carbonization temperature is preferably in the range of 600 to 1,200 ° C., more preferably 800.
The range is up to 1,000 ° C. The activation of the ultrafine carbon fibers can be performed by subjecting the ultrafine carbon fibers to a gasification reaction with steam. The conjugate fiber, ultrafine carbon fiber and ultrafine activated carbon fiber shaped object of the present invention include chopped strands, non-woven fabrics, cloths, felts, papers,
Examples include long fibers, which can be produced by a known method.

[0015]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. The methods for measuring the physical properties of each fiber in this example are as follows. (1) Fiber diameter A scanning electron microscope JSM-T220A manufactured by JEOL Ltd. was used for photography, and the fiber diameter was measured based on the electron microscope photograph. (2) Specific surface area Measured using Bell Soap 28SA manufactured by Bell Japan.

[Example 1] Phenol 1,000 g, 37
Mass% formalin 733.2g, oxalic acid 5g with a stirrer,
A reaction vessel equipped with a reflux condenser was charged, and 10 minutes were taken in 40 minutes.
The temperature was raised to 0 ° C. and then this temperature was maintained for 4 hours. 20
By heating to 0 ° C, dehydration and concentration under reduced pressure, and then cooling, a novolac type phenol resin 1 having a softening point of 125 ° C 1
010 g was obtained. Phenol resin powder obtained by repeating the same operation three times and polypropylene (Y-6005GM, manufactured by Idemitsu Petrochemical Co., Ltd.) having a MI measured at 230 ° C. and a load of 21.18 N of 60 g / 10 min were 30 by mass. :
Mixed to 70. 2000g of this mixed resin
Was mixed at 230 ° C. using a kneading PCM30 same-direction twin-screw extruder manufactured by Ikegai Tekko Co., Ltd. to obtain composite resin pellets. Next, the obtained composite resin was melt-spun at a nozzle temperature of 170 ° C. to obtain sea-island type uncured composite fibers. The uncured composite fiber obtained was placed in a hydrochloric acid-formaldehyde aqueous solution (hydrochloric acid 18% by mass, formaldehyde 10% by mass) at 96 ° C. for 24 hours.
It was immersed for a time to obtain a cured fiber. Next, this cured fiber
Carbonization was carried out in a nitrogen stream at 600 ° C. for 10 minutes to remove polypropylene as a sea component to obtain a phenolic ultrafine carbon fiber. The obtained phenol-based ultrafine carbon fiber was activated with steam at 900 ° C. for 5 minutes to obtain an ultrafine activated carbon fiber. The fiber diameter and specific surface area of these ultrafine carbon fibers and ultrafine activated carbon fibers were measured by the above-mentioned methods. The results are shown in Table 1. Electron micrographs of the obtained phenolic ultrafine carbon fibers are shown in FIGS. 1 and 2. FIG. 1 is a 1000 × electron microscope photograph, and FIG. 2 is a 5000 × electron microscope photograph. From this electron micrograph, it was confirmed that polypropylene (sea part) disappeared due to heat, and a large number of ultrafine carbon fibers (average fiber diameter 0.2 μm) extending long in the fiber axis direction were formed independently. Was done. By activating the ultrafine carbon fibers, it was possible to obtain ultrafine activated carbon fibers having a specific surface area of 2020 m ² / g.

[Second Embodiment] In the first embodiment, MI is 6
Polypropylene 0g / 10 minutes, 230 ℃, load 21.
The average fiber diameter was 30 μm in the same manner as in Example 1 except that polypropylene (Y-2000GV manufactured by Idemitsu Petrochemical Co., Ltd.) having an MI measured at 18 N of 20 g / 10 min was used.
m cured composite fiber was obtained. In the same manner as in Example 1, the obtained composite fiber was carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber. Table 1 shows the measurement results of these. From the electron micrograph, it was confirmed that the ultrafine carbon fibers (average fiber diameter 0.2 μm) were individually formed. Moreover, the specific surface area of 2050 m is obtained by activating the ultrafine carbon fiber.
It was possible to obtain ² / g of ultrafine activated carbon fibers.

[Embodiment 3] In Embodiment 1, the MI is 6
Polypropylene 0g / 10 minutes, 230 ℃, load 21.
The average fiber diameter was 30 μm in the same manner as in Example 1 except that polypropylene (Y-900GV manufactured by Idemitsu Petrochemical Co., Ltd.) having MI measured at 18 N of 10 g / 10 min was used.
A cured composite fiber of In the same manner as in Example 1, the obtained composite fiber was carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber. Table 1 shows the measurement results of these. From the electron micrograph, it was confirmed that the ultrafine carbon fibers (average fiber diameter 0.2 μm) were individually formed. In addition, by activating the ultrafine carbon fiber, the specific surface area is 1970 m ²
It was possible to obtain ultrafine activated carbon fibers of / g.

[Embodiment 4] In Embodiment 1, MI is 6
0 g / 10 min polypropylene, density 0.963 g / c
MI measured at m ³ , 190 ° C., load 21.18N
Is 14 g / 10 min polyethylene (made by Idemitsu Petrochemical Co.,
A cured composite fiber having an average fiber diameter of 30 μm was obtained in the same manner as in Example 1 except that the composite fiber was changed to 110 Y). In the same manner as in Example 1, the obtained composite fiber was carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber.
Table 1 shows the measurement results of these. From the electron micrograph, it was confirmed that the ultrafine carbon fibers (average fiber diameter 0.2 μm) were individually formed. Further, by carrying out activation treatment of the ultrafine carbon fibers, it was possible to obtain ultrafine activated carbon fibers having a specific surface area of 2030 m ² / g.

[Embodiment 5] In Embodiment 1, MI is 6
0g / 10min polypropylene, density 0.964g / c
MI measured at m ³ , 190 ° C., load 21.18N
23 g / 10 min polyethylene (made by Idemitsu Petrochemical,
A cured composite fiber having an average fiber diameter of 30 μm was obtained in the same manner as in Example 1 except that the composition was changed to 120 YK). In the same manner as in Example 1, the obtained composite fiber was carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber.
Table 1 shows the measurement results of these. From the electron micrograph, it was confirmed that the ultrafine carbon fibers (average fiber diameter 0.2 μm) were individually formed. By activating the ultrafine carbon fiber, an ultrafine activated carbon fiber having a specific surface area of 1990 m ² / g could be obtained.

[Embodiment 6] In Embodiment 1, MI is 6
0g / 10min polypropylene, density 0.940g / c
MI measured at m ³ , 190 ° C., load 21.18N
Is 20 g / 10 min polyethylene (made by Idemitsu Petrochemical,
A cured composite fiber having an average fiber diameter of 30 μm was obtained in the same manner as in Example 1 except that the composite fiber was changed to 2074G). In the same manner as in Example 1, the obtained composite fiber was carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber.
Table 1 shows the measurement results of these. From the electron micrograph, it was confirmed that the ultrafine carbon fibers (average fiber diameter 0.2 μm) were individually formed. Further, by carrying out activation treatment of the ultrafine carbon fibers, it was possible to obtain ultrafine activated carbon fibers having a specific surface area of 2070 m ² / g.

[0022]

[Table 1]

[Comparative Example 1] The phenol resin synthesized in Example 1 was melt-spun at a nozzle temperature of 150 ° C to obtain a phenol fiber raw fiber. Further, the obtained raw fiber was immersed in a hydrochloric acid-formaldehyde aqueous solution (hydrochloric acid 18% by mass, formaldehyde 10% by mass) at 96 ° C. for 24 hours to obtain a cured fiber. Next, the cured fiber was placed in a nitrogen stream at 900
Carbonization was carried out under the condition of 30 ° C. for 30 minutes to obtain a phenolic carbon fiber. The obtained phenol-based carbon fiber was activated with steam at 900 ° C. for 5 minutes to obtain activated carbon fiber. For these carbon fibers and activated carbon fibers,
The fiber diameter and the specific surface area were measured by the above methods. The results are shown in Table 2. Electron micrographs of the obtained phenolic carbon fibers are shown in FIGS. 3 and 4. FIG. 3 is a 1000 × electron microscope photograph, and FIG. 4 is a 5000 × electron microscope photograph. The obtained phenolic carbon fiber has an average fiber diameter of 10 μm, and the activated carbon fiber has a specific surface area of 500 m ^2.
/ G.

Comparative Example 2 In Example 1, MI was 6
Polypropylene 0g / 10 minutes, 230 ℃, load 21.
A cured conjugate fiber having an average fiber diameter of 30 μm was obtained in the same manner as in Example 1 except that polypropylene (Idemitsu Petrochemical Co., Ltd., 2034G) having an MI measured at 18 N of 34 g / 10 min was used. In the same manner as in Example 1, the obtained composite fiber was carbonized to obtain an ultrafine carbon fiber, and this carbon fiber was activated to obtain an activated carbon fiber. The measurement results of these are shown in Table 2. Electron micrographs of the obtained ultrafine carbon fibers are shown in FIGS. 5 and 6. FIG. 5 is a 1000 × electron microscope photograph, and FIG. 6 is a 5000 × electron microscope photograph. From the electron micrograph, it was confirmed that the ultrafine carbon fibers (average fiber diameter: 0.2 μm) were individually formed, but were fused or shrunk. By activating the ultrafine carbon fibers, it was possible to obtain ultrafine activated carbon fibers having a specific surface area of 2000 m ² / g.

[Comparative Example 3] In Example 1, MI was 6
Polypropylene 0g / 10min, 190 ℃, load 21.
A composite resin pellet was obtained in the same manner as in Example 1 except that polyethylene (210 JZ manufactured by Idemitsu Petrochemical Co., Ltd.) having an MI measured at 18 N of 4.7 g / 10 min was used. Next, the obtained composite resin was melt-spun at a nozzle temperature of 150 ° C. In the spinning step, stable extrusion could not be carried out, and the fiber was broken, so good spinning could not be carried out, but sea-island type uncured composite fibers having an average fiber diameter of 100 μm could be obtained. In the same manner as in Example 1, the obtained composite fiber was cured and carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber. The measurement results of these are shown in Table 2. Ultra-fine carbon fiber (average fiber diameter 0.3 μm) from electron micrograph
It was confirmed that each of these was formed in an independent state. By activating the ultrafine carbon fiber, an ultrafine activated carbon fiber having a specific surface area of 1980 m ² / g could be obtained.

[Comparative Example 4] In Example 1, MI was 6
Polypropylene 0g / 10 minutes, 230 ℃, load 21.
Composite resin pellets were obtained in the same manner as in Example 1 except that polypropylene (Y-400GP, manufactured by Idemitsu Petrochemical Co., Ltd.) having an MI measured at 18 N of 4.0 g / 10 min was used. Next, the obtained composite resin was melt-spun at a nozzle temperature of 170 ° C. In the spinning process, stable extrusion could not be performed, and the fiber was broken, so good spinning could not be performed, but the average fiber diameter was 100 μm.
It was possible to obtain a sea-island type uncured composite fiber. In the same manner as in Example 1, the obtained composite fiber was cured and carbonized to obtain carbon fiber, and this carbon fiber was activated to obtain activated carbon fiber. The measurement results of these are shown in Table 2.
Ultrafine carbon fiber (average fiber diameter 0.3
It was confirmed that (.mu.m) was formed in an independent state. Further, by carrying out activation treatment of the ultrafine carbon fibers, it was possible to obtain ultrafine activated carbon fibers having a specific surface area of 2030 m ² / g.

[0027]

[Table 2]

[0028]

EFFECTS OF THE INVENTION By carbonizing the conjugate fiber obtained from the resin composition for conjugate fiber of the present invention, the average fiber diameter is 0.
Ultrafine carbon fibers of 5 μm or less can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a 1000 × electron micrograph of a phenolic ultrafine carbon fiber aggregate in Example 1.

FIG. 2 is a 5000 × electron micrograph of a phenolic ultrafine carbon fiber aggregate in Example 1.

3 is a 1000 times electron micrograph of a phenolic carbon fiber aggregate in Comparative Example 1. FIG.

FIG. 4 is a 5000 × electron micrograph of a phenolic carbon fiber aggregate in Comparative Example 1.

5 is a 1000 times electron micrograph of a phenolic ultrafine carbon fiber aggregate in Comparative Example 2. FIG.

FIG. 6 is a 5000 × electron micrograph of a phenolic ultrafine carbon fiber aggregate in Comparative Example 2.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) C08L 61:06) (72) Inventor Motoyoshi Ito 700 Sukudaiji-cho, Takasaki-shi, Gunma Gunei Chemical Industry Co., Ltd. (72) Inventor Masao Irizawa 700 Yadodaiji-cho, Takasaki-shi, Gunma Gunei Chemical Industry Co., Ltd. (72) Inventor Asao Otani 1-5-1, Tenjin-cho, Kiryu-shi Gunma Prefecture (Reference) 4J002 BB031 BB121 CC032 GK01 4L035 AA05 BB31 CC20 FF01 LA01 LA07 MA10 ME01 ME02 ME10 4L037 AT11 CS03 CS06 FA03 FA05 FA12 PA38 PC05 PF31 PF51

Claims (7)

[Claims] 1. MI measured under the conditions of 10 to 50% by mass of a phenol resin, a temperature of 230 ° C. and a load of 21.18 N.
A resin composition for composite fibers comprising 90 to 50% by mass of polypropylene having a (melt index) of 10 to 100 g / 10 min. 2. Phenolic resin 10 to 50 mass% and density 0.940 g / cm ³ or more, temperature 190 ° C., load 21.
90 to 50% by mass of polyethylene having an MI (melt index) of 10 to 30 g / 10 minutes measured under the condition of 18N
A resin composition for a composite fiber, which comprises 3. The resin composition according to claim 1, wherein the phenol resin is a novolac type phenol resin having a softening point of 90 ° C. or higher. 4. The average fiber diameter obtained by spinning the resin composition according to claim 1 is 5 to 1.
00 μm composite fiber. 5. An ultrafine carbon fiber having an average fiber diameter of 0.5 μm or less, which is obtained by carbonizing the composite fiber according to claim 4. 6. An ultrafine activated carbon fiber obtained by activating the ultrafine carbon fiber according to claim 5. 7. A shaped article obtained by shaping the fiber according to any one of claims 4 to 6.