JPH09176922A - Activated carbon fiber manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention contains many pores having a pore size of more than 20 Å, so-called mesopores, has excellent antibacterial properties, and exhibits antibacterial properties by containing a small amount of antibacterial agent. And a method for producing a new activated carbon fiber that can be used in a wide range of applications with a high activation yield and extremely easily. The method for producing activated carbon fibers according to the present invention is a cured novolac resin fiber obtained by adding 10 to 120 parts by weight of polyvinyl butyral containing an antibacterial agent to 100 parts by weight of an uncured novolac resin, melt spinning and curing the mixture. Is activated by carbonization. With this manufacturing method,
The above object can be achieved.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fibrous activated carbon, that is, activated carbon fibers, and more specifically, for example, household and commercial air purifiers and water purifiers, general-purpose masks and gas masks,
The present invention relates to a method for producing a novel antibacterial activated carbon fiber containing a large amount of so-called mesopores having a pore size of more than 20Å, which is prepared from a cured novolac resin fiber that is widely used as a medical adsorbent and a sanitary material.

2. Description of the Related Art Activated carbon fibers having a cellulosic fiber as a precursor, a polyacrylonitrile fiber as a precursor, a pitch fiber as a precursor, and a cured novolac resin fiber as a precursor. However, it is difficult to obtain an activated carbon fiber which contains a large amount of so-called mesopores, each having a pore size exceeding 20 Å, and which has antibacterial properties. For applications that require antibacterial properties and at the same time need to adsorb relatively large molecules, conventional activated carbon fibers developed only with micropores (pore diameter 20 Å or less) are unsuitable and contain a lot of mesopores. In addition, activated carbon fibers having antibacterial properties have been strongly desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the conventional circumstances, and an object of the present invention is to include many pores having a pore diameter of more than 20Å, so-called mesopores, and to have excellent durability. It is an object of the present invention to provide a method for producing a new activated carbon fiber which has antibacterial properties and exhibits antibacterial properties with a small amount of antibacterial agent and which can be used in a wide variety of applications with good activation yield and extremely easily.

According to the manufacturing method of the present invention, 10 to 120 parts by weight of polyvinyl butyral containing an antibacterial agent is added to 100 parts by weight of uncured novolak resin, and the mixture is melt-spun and cured. By activated carbonization of the obtained cured novolac resin fiber, activated carbon fiber containing a large amount of mesopores having a pore size of more than 20 Å and having antibacterial properties and usable for a wide range of applications can be produced with good activation yield. By appropriately increasing or decreasing the amount of polyvinyl butyral, it is possible to increase or decrease the proportion of pores having a pore size of more than 20Å in all the pores. In addition, before the step of melt spinning the uncured novolac resin, it is sufficient to simply add polyvinyl butyral containing an antibacterial agent, and the antibacterial activated carbon fiber can be manufactured very easily without the complexity of the manufacturing process. The reason why the antibacterial activated carbon fiber containing a large amount of mesopores can be produced with a high activation yield by the present invention is not clear, but the compatibility of polyvinyl butyral and uncured novolac resin is extremely good, and fine and uniform mutual dispersion is possible. It is believed that That is, it has been found that polyvinyl butyral has a large amount of volatilized portions and a small amount of residual carbon in the carbonization step, and in contrast, cured novolac resin fibers have an extremely large amount of residual carbon. Therefore, it can be presumed or inferred that the carbonized polyvinyl butyral-containing cured novolac resin fibers that are finely and uniformly dispersed in each other are those in which fine pores derived from volatilization of polyvinyl butyral are uniformly generated. Therefore, in the subsequent activation step, water vapor, which is an activating gas, easily diffuses inside the fiber, so that the increase in the pore size due to the oxidation reaction inside the fiber easily progresses, and the increase in the pore size is It is thought that this is because the fiber tends to advance faster than the fiber is thinned due to the oxidation reaction on the surface portion. Furthermore, since the antibacterial agent can be concentratedly present in the fine pores derived from the evaporation of polyvinyl butyral, it is considered that even a small amount of the antibacterial agent exhibits the antibacterial property extremely effectively. Hereinafter, the present invention will be described in detail. The uncured novolak resin used in the present invention is, for example, alkylphenols or other substituted phenols in addition to phenol, polyhydric phenols and formaldehyde, and aldehydes such as paraformaldehyde as raw materials, and are generally known by a conventional method. It is obtained by reacting under an acidic catalyst. As the antibacterial agent used in the present invention, a silver compound such as silver nitrate, silver acetate, or silver acetylacetonate can be used. Further, polyvinyl butyral used in the present invention is a polymer obtained by reacting polyvinyl alcohol and butyraldehyde under an acidic catalyst, also called butyral resin, and industrial products are copolymers of vinyl acetate, vinyl alcohol, and vinyl butyral. , Those having various degrees of polymerization and butylation can be used. To add an antibacterial agent to polyvinyl butyral,
For example, when silver nitrate, which is a silver compound, is used as the antibacterial agent, there is a method in which a predetermined amount of polyvinyl butyral and silver nitrate are uniformly dissolved in a solvent such as methanol, and then methanol is volatilized by evaporation or the like. It is also possible to directly add an antibacterial agent to polyvinyl butyral which has been heated to a molten state and melt-mixed it. As a method of adding polyvinyl butyral containing an antibacterial agent to the uncured novolac resin, for example, the antibacterial agent is added when the reaction is finished in the manufacturing process of the uncured novolac resin, that is, when the resin temperature is high and still in a molten state. The allowed polyvinyl butyral can be mixed. Further, polyvinyl butyral containing an uncured novolac resin and an antibacterial agent may be heated and melt-mixed. The amount of polyvinyl butyral containing an antibacterial agent added to 100 parts by weight of the uncured novolac resin in the present invention is 10 to 120 parts by weight. If the amount is less than 10 parts by weight, the effect is small and it is difficult to obtain activated carbon fibers having a large amount of mesopores. If the amount is more than 120 parts by weight, the curing reaction after melt spinning is difficult to proceed, and a cured novolak resin containing polyvinyl butyral containing an antibacterial agent. It is not preferable because it becomes difficult to obtain fibers. The amount of the antibacterial agent contained in polyvinyl butyral is 10 parts by weight or less based on 100 parts by weight of polyvinyl butyral. 1
Even if it is contained in an amount of more than 0 parts by weight, the antibacterial property is not particularly enhanced, and the amount of the antibacterial agent dropped from the resulting activated carbon fiber is increased, which is not preferable. Next, the uncured novolac resin containing polyvinyl butyral containing an antibacterial agent is melt-spun. The method of melt spinning is not particularly limited, for example, a known so-called melt spinning method in which a molten resin discharged from a spinneret is drawn by a roll, a method of centrifuge spinning the molten resin into a disk, and a melt discharged from the spinneret. A so-called melt blown method in which a resin is spun by a pulling force of a heated air flow can be used.
The uncured novolak resin fiber containing polyvinyl butyral containing the spun antibacterial agent is dipped in a cured aqueous solution containing, for example, hydrochloric acid and formaldehyde as main components, gradually heated and kept at a temperature of 90 ° C. or higher for several hours. As a result, a cured novolac resin fiber is obtained. Next, in order to activate carbonization of the obtained cured novolac resin fiber, for example, carbonization is performed in an inert gas at 700 ° C. or higher to form carbon fiber, and then steam, carbon dioxide, air or an oxidizing gas in which these are mixed is used. It may be carried out according to a known method of introducing and activating it, and the method is not particularly limited. In addition, it can be used in any direction even if activated simultaneously with carbonization. As described above, an antibacterial activated carbon fiber containing a large number of pores having a pore diameter of more than 20 Å, so-called mesopores, and having excellent antibacterial properties, which can be used for a wide range of purposes, has a high activation yield and is extremely easy. Can be manufactured.

EXAMPLES Specific embodiments of the present invention will be shown below by way of examples. [Example 1] 1.2 kg of phenol, 0.6 kg of 50% formalin and 3.5 g of oxalic acid were placed in a 3 liter flask, reacted at reflux temperature for 4 hours, and then vacuum dehydration concentration was performed under heating to soften the softening point. 1 kg of uncured novolak resin at 110 ° C. was obtained. On the other hand, polyvinyl butyral 300
200 g (manufactured by Wako Pure Chemical Industries, Ltd.) and 2 g of silver nitrate were dissolved in 200 g of methanol and homogeneously mixed, and then methanol was removed by a rotary evaporator and then a reduced pressure heating dryer to obtain polyvinyl butyral containing an antibacterial agent. 200 g of the uncured novolak resin and 200 g of the antibacterial agent-containing polyvinyl butyral were heated and melted, and mixed and stirred to obtain an uncured novolak resin containing the antibacterial agent-containing polyvinyl butyral. This uncured novolac resin has 2 holes
0, using a spinneret with a hole diameter of 0.2 mmφ, 520 m / m
Melt spinning was performed at a speed of in to obtain an uncured novolac resin fiber containing an antibacterial agent-containing polyvinyl butyral. The novolac resin fiber was dipped in a curing aqueous solution containing formaldehyde and hydrochloric acid as main components, heated to 95 ° C. at a rate of 0.5 ° C./min, and held for 8 hours to obtain a cured novolac resin fiber. This fiber was wrapped in carbon cloth and heated to 900 ° C at a rate of 5 ° C / min in a nitrogen stream,
It hold | maintained at 00 degreeC for 30 minutes, and obtained carbon fiber. This carbon fiber was activated with steam using nitrogen as a carrier for 1 hour to obtain an activated carbon fiber. The activation yield of the obtained activated carbon fiber based on the carbon fiber is as high as 30%, and the proportion of mesopores having a pore size of more than 20Å in the total pore volume is 82%.
And many. Further, the obtained activated carbon fiber retained its durability even after being immersed in running tap water for 20 days, and the antibacterial property was active. [Example 2] 1.2 kg of phenol, 0.6 kg of 50% formalin and 3.5 g of oxalic acid were placed in a 3 liter flask and reacted at a reflux temperature for 4 hours. After that, vacuum dehydration concentration was performed under heating until the internal temperature of the reaction product rises to 200 ° C., 110 g of antibacterial agent-containing polyvinyl butyral was added to the flask, and the mixture was stirred by melting and mixing, and uncured with antibacterial agent-containing polyvinyl butyral. A novolac resin was obtained.
The antibacterial agent-containing polyvinyl butyral was obtained by the same method as shown in Example 1. The weight of the uncured novolac resin in the flask before mixing with polyvinyl butyral was 1 kg. The number of holes in the obtained mixed resin is 2
0, discharge amount 0.4g / mi from a die with a hole diameter of 0.2mmφ
Discharge with n ・ Hole, and heat air flow of 110 ℃ at 30
It was made to flow through a slit having a width of 0.3 mm at a flow rate of N liter / min.Hole and spun by a so-called melt blown method. The polyvinyl butyral-containing uncured novolac resin fiber is immersed in a curing aqueous solution containing formaldehyde and hydrochloric acid as main components, and the temperature is 95 ° C. at a rate of 0.5 ° C./min.
After the temperature was raised to, the mixture was kept for 8 hours to obtain a cured polyvinyl butyral-containing novolak resin fiber. Wrap this fiber in a carbon cloth and keep it in a nitrogen stream at a rate of 5 ° C / min for 900
The temperature was raised to ℃ and kept at 900 ℃ for 30 minutes to obtain carbon fiber. This carbon fiber was activated with steam using nitrogen as a carrier for 1 hour to obtain an activated carbon fiber. The activation yield of the obtained activated carbon fiber based on the carbon fiber was as high as 33%, and the ratio of the volume of mesopores having a pore diameter of more than 20Å in the total pore volume was 26%. The obtained activated carbon fiber retained its durability even after being immersed in running tap water for 20 days, and the antibacterial property was active. Comparative Example 1 200 g of the uncured novolac resin obtained by the same method as in Example 1 was heated and melted, 2 g of silver nitrate was added thereto, and the mixture was stirred to obtain an uncured novolac resin containing no polyvinyl butyral. This uncured novolac resin was melt-spun at a speed of 520 m / min using a spinneret having 20 holes and a hole diameter of 0.2 mmφ to obtain an uncured novolac resin fiber. This novolac resin fiber is dipped in a curing aqueous solution containing formaldehyde and hydrochloric acid as main components, heated to 95 ° C. at a rate of 0.5 ° C./min, and then
After holding for 8 hours, a cured novolak resin fiber was obtained. Wrap this fiber in carbon cloth and in a nitrogen stream at 5 ° C / min
The temperature was raised to 900 ° C. at a rate of, and held at 900 ° C. for 30 minutes to obtain carbon fibers. This carbon fiber was activated with steam using nitrogen as a carrier for 1 hour to obtain an activated carbon fiber. The activation yield of this activated carbon fiber based on carbon fiber is 25%.
The ratio of the volume of mesopores having a pore diameter of more than 20Å in the total pore volume was as small as 5%. Further, the obtained activated carbon fiber became inactive in antibacterial property after being immersed in running tap water for 20 days. Examples 1 and 2
The results obtained in Comparative Example 1 are summarized in Table 1 below. The activation yield is the yield based on carbon fiber after carbonization,
Mesopore volume (%) is 20Å in the total pore volume
It is the ratio of the volume of mesopores that exceeds. The mesopore volume (%) was calculated from the micropore volume by the MP method and the mesopore volume by the DH method based on the nitrogen adsorption data by BELSORP36 (manufactured by Bell Japan Ltd.). In addition, the samples used for the antibacterial test are those obtained in Example 1,
2 and 2 g of the activated carbon fibers obtained in Comparative Example 1 were used after being dipped in tap water having a flow rate of 2 l / min for 20 days. If the antibacterial property is active even after the treatment under these conditions, it can be judged that the antibacterial property is excellent. Antibacterial test is J
It carried out according to the antibacterial test of the textile according to IS L-1902. That is, an activated carbon fiber treated under the above conditions was placed on an agar medium containing Escherichia coli or Staphylococcus aureus.
After culturing at 24 ° C. for 24 hours, whether the antibacterial activity is active or inactive was evaluated depending on the presence or absence of a growth inhibitor (halo) formed around the activated carbon fiber. If it had a growth inhibitor (halo), it was made active, and if it did not have it, it was made inactive. As is clear from Table 1, the activated carbon fiber obtained by the production method of the present example has an activation yield based on carbon fiber as compared with the activated carbon fiber obtained by Comparative Example 1 of the conventional production method. Is much higher, and the ratio of the volume of mesopores having a pore diameter of more than 20 Å in the total pore volume is large, and it has excellent durability and antibacterial properties.

[Table 1]

According to the present invention described in detail above, the pore diameter is 2
(EN) Provided is a method for producing activated carbon fibers which have a large number of pores exceeding 0 Å, so-called mesopores, and which have excellent durability and antibacterial properties and which can be used in a wide range of applications with a high activation yield and extremely easily. it can.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kunio Hanakami, 700 Sukudaiji-cho, Takasaki-shi, Gunma Gunei Chemical Industry Co., Ltd. In-house (72) Inventor Satoru Yoshida 700 No. 700, Yadodai-cho, Takasaki-shi, Gunma Gunei Chemical Industry Co., Ltd.

Claims (3)

[Claims] 1. 10 to 12 polyvinyl butyral containing an antibacterial agent per 100 parts by weight of an uncured novolac resin.
A method for producing an activated carbon fiber, which comprises adding 0 part by weight and carbonizing a cured novolac resin fiber obtained by melt spinning and curing. 2. The method for producing activated carbon fiber according to claim 1, wherein the amount of the antibacterial agent contained in the polyvinyl butyral is 10 parts by weight or less with respect to 100 parts by weight of the polyvinyl butyral. 3. The method for producing activated carbon fiber according to claim 1, wherein the antibacterial agent is a silver compound.