JP2006104605A - Functional fiber having photocatalyst activity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional fiber sufficiently utilizing photocatalyst functions of a metal oxide having a photocatalyst activity and having various functions such as deodorizing, antimicrobial, mildewproofing and anti-staining properties. <P>SOLUTION: The functional fiber is characterized as follows. The fiber has a multilayer structure comprising porous layers and dense layers alternately arranged and metal oxide fine particles having the photocatalyst activity are contained in the dense layers. The pore surface area of the fiber is preferably within the range of 10-40 m<SP>2</SP>/g and the metal oxide fine particles are preferably titanium oxide. The particle diameter of the metal oxide fine particles is preferably 10-100 nm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a functional fiber having photocatalytic activity. More specifically, the present invention relates to a functional fiber that can fully utilize the photocatalytic activity and has various functions such as deodorizing property, antibacterial / antifungal property, and antifouling property.

In recent years, metal compounds having photocatalytic activity such as titanium oxide have attracted attention, and application to various uses such as deodorizing, antibacterial, antifungal and antifouling has been proposed. A fiber product containing a metal compound having such photocatalytic activity has also been proposed. However, metal compounds having photocatalytic activity have problems such as degradation of the base fiber itself, or those contained in the fiber cannot exhibit their functions, and fibers that can fully utilize the photocatalytic activity have not yet been obtained. The current situation is not.

For example, taking the deodorizing function as an example, as long as it does not have a conventional photocatalytic activity, a deodorizing fiber in which an adsorbent is supported on the fiber or an activated carbon fiber having a microvoid has been proposed. Since these fibers adsorb malodorous components in adsorbents and microvoids, there is a problem that malodorous odors cannot be removed when the saturated adsorption amount is exceeded.

In recent years, deodorant fibers have been proposed in which metal oxides having photocatalytic activity such as titanium oxide are contained in the fibers. For example, Patent Document 1 discloses a deodorizing fiber containing a photocatalyst and an adsorbent, and a fiber having a core-sheath structure in which the concentration of the photocatalyst in the sheath is higher than that in the core is preferable. According to such a fiber, since the malodorous component is decomposed by the photocatalyst, the problem that the malodor cannot be removed when the saturated adsorption amount is exceeded is solved. However, in such a core-sheath structure fiber, malodorous components are adsorbed only on the surface of the fiber, so that the adsorption capacity is poor, and therefore it cannot be said that the photocatalytic function is effectively utilized.

In order to utilize the photocatalytic function, there is also a proposal to include a metal oxide having photocatalytic activity in a porous fiber (for example, Patent Document 2). According to this method, the surface area of the fiber increases and the metal oxide present in the surface layer increases, so it seems that the photocatalytic function can be used effectively, but spinning processability (electrostatic generation), dyeability (color development) In addition, the metal oxide fine particles in the surface layer portion easily fall off during spinning, dyeing, or the like, or washing, so that a sufficient deodorizing effect cannot be obtained. There is.

On the other hand, since the photocatalyst also degrades the base fiber itself, there is a problem that the fiber is discolored or the strength is lowered. Therefore, in Patent Document 3, composite metal oxide fine particles containing titanium oxide and silicon oxide are used. By using such fine particles, discoloration and strength reduction of the fiber can be suppressed to some extent. However, the use of such special fine particles increases the cost, and it is preferable that the amount of the fine particles is large for the deodorizing ability. If the amount is increased, the fiber is still discolored or the strength is decreased. There is a problem of doing.
JP-A-8-284011 JP-A-10-57816 JP 2004-162245 A

This invention is made | formed in view of the said conventional problem, The subject is providing the functional fiber which can fully utilize a photocatalytic function.

As a result of diligent studies to achieve the above-mentioned object, the present inventor has reached the present invention shown below.

(1) A functional fiber characterized in that it is a multilayer structure fiber in which a porous layer and a dense layer are alternately arranged, and metal oxide fine particles having photocatalytic activity are contained in the dense layer.
(2) The functional fiber according to (1), wherein the pore surface area of the fiber is in the range of 10 to 40 m ² / g.
(3) The functional fiber according to (1) or (2), wherein the metal oxide fine particles are titanium oxide.
(4) The functional fiber according to any one of (1) to (3), wherein the particle diameter of the metal oxide fine particles is in the range of 10 to 100 nm.
(5) The functional fiber according to any one of (1) to (4), wherein 1 to 10 parts by weight of metal oxide fine particles are contained with respect to 100 parts by weight of the fiber matrix.
(6) The functional fiber according to any one of (1) to (5), wherein the functional fiber is a multilayer structure fiber made of an acrylonitrile-based polymer.

In the functional fiber of the present invention, metal oxide fine particles having photocatalytic activity are contained in a dense layer of a multilayer structure fiber in which a porous layer and a dense layer are alternately arranged. The photocatalytic function can be effectively utilized. Therefore, various kinds of bad odors can be effectively decomposed and deodorized, and furthermore, since they have various functions such as antibacterial properties, anti-fouling properties, and antifouling properties, they can be used in various applications. Can be applied.

The present invention is described in detail below. First, in the present invention, the base fiber is a multilayer structure fiber in which porous layers and dense layers are alternately arranged in the fiber cross-sectional direction. As the number of layers of the multilayer structure fiber, it has a multilayer structure of two or more layers composed of one porous layer and one dense layer. In the case of three or more layers, the porous layer and the dense layer are alternately arranged. Must be arranged.
Furthermore, the metal oxide fine particles having photocatalytic activity must be contained on the dense layer side. If it is contained on the dense layer side, it may be contained also on the porous layer side, but the fine particles on the porous layer side are easy to fall off, and if it is contained on the dense layer side, it is sufficient. From the viewpoint of cost, it is preferable to contain only in the dense layer side in order to obtain the function.

In the present invention, the base fiber is a multilayer structure fiber in which a porous layer and a dense layer are alternately arranged, and the pore surface area of the fiber is preferably in the range of 10 to 40 m ² / g, more preferably. The range is ^{20 to} 40 m ² / g. When the pore surface area of the fiber is less than 10 m ² / g, the photocatalytic function may not be sufficiently utilized, for example, the adsorption area of malodorous components becomes small. Moreover, when it exceeds 40 m < ² > / g, there exists a possibility of producing difficulty in workability, such as spinnability (electrostatic property) and dyeability (coloring property).

The metal oxide fine particles having photocatalytic activity are substances that generate electrons and holes on the surface thereof by ultraviolet irradiation and generate active oxygen having strong oxidizing power from surrounding water and oxygen. Specifically, Se, Ge, Si, Ti, Zn, Cu, Al, Sn, Ga, In, P, As, Sb, C, Cd, S, Te, Ni, Fe, Co, Ag, Mo, Sr , W, Cr, Ba, Pb and other compounds such as oxides which are insoluble in water. Among these, one selected from titanium oxide, zinc oxide and tungsten oxide alone or in combination of two or more is preferable, and titanium oxide is preferably used from the viewpoint of safety and price.

Further, the particle diameter of the metal oxide fine particles having photocatalytic activity is not particularly limited, but the average primary particle diameter is preferably in the range of 10 to 100 nm, more preferably 15 to 50 nm, more preferably. It is the range of 15-30 nm. Of course, the smaller the average primary particle diameter is, the higher the activity as a photocatalyst is. However, when the average primary particle diameter is less than 10 nm, the handleability (dust) and dispersibility (aggregation) when contained in the fiber are improved. May cause problems. On the other hand, when the average primary particle diameter exceeds 100 nm, there is a possibility that a sufficient function cannot be obtained.

The amount of the metal oxide fine particles having photocatalytic activity can be selected from a wide range according to the required deodorizing properties, antibacterial / antifungal properties, antifouling properties and the like. If the amount of the fine particles is small, the required ability may not be obtained. If the amount is too large, the ability is excellent, but the base fiber may be deteriorated or the physical properties of the fiber may be impaired. The amount is preferably 1 to 10 parts by weight, more preferably 1.5 to 5 parts by weight, based on 100 parts by weight of the base material.

As described above, the functional fiber of the present invention is a multi-layer structure fiber in which a porous layer and a dense layer are alternately arranged, and is a so-called composite fiber made of the same or different polymers. Such a polymer may be a homopolymer or a copolymer as long as it can form fibers, such as polyester fibers, polyamide fibers, polyolefin fibers, ethylene-vinyl alcohol copolymer fibers, polyvinyl chloride. Fiber, polyvinylidene chloride fiber, polyurethane fiber, acrylic fiber, polyvinyl alcohol fiber, polyclar fiber, fluorine fiber, protein-acrylonitrile copolymer fiber, polyglycolic acid fiber, synthetic resin such as phenol resin fiber, acetate Examples thereof include polymers forming semi-synthetic fibers such as fibers and regenerated fibers such as rayon and cupra. Among them, acrylic fiber made of acrylonitrile polymer is most suitable as a base fiber of the fiber of the present invention because it has high resistance to photocatalytic activity.

The means for obtaining the multilayer structure fiber can be arbitrarily selected from known composite fiber production methods (side-by-side type, random composite type), but preferably two components as described in JP-B-59-7802 The so-called random composite type is used, in which the stock solution of Kenys Mixer (manufactured by Kenix, USA) and ISG Mixer, which has an arbitrary number of elements, are passed through the spinning stock solution and the composite flow is guided and discharged by the flow dividing plate of the die introduction hole. By doing so, the object of the present invention can be advantageously achieved.

  Further, the functional fiber of the present invention needs to have a porous layer and a dense layer. The fiber having such a structure can be obtained by combining a known method for producing porous fibers and a technique for producing ordinary dense fibers. For example, a method of adding a polymer having low compatibility with the polymer serving as the base fiber to the spinning solution on the porous layer side to obtain a capillary porous structure by phase separation, spinning a non-volatile solvent on the porous layer side A method for obtaining a porous structure by adding to the stock solution and extracting the solvent after spinning, and filling the swollen gel tow during the production process with a water-soluble compound, followed by drying and post-treatment to elute the packed material and make it porous Examples thereof include a method for obtaining quality, or a method in which the same or different polymers having different densification conditions are used, and the treatment is carried out under the condition that only one polymer is densified.

Below, the manufacturing method of the acrylic fiber using two types of polymers from which acrylonitrile content differs as an example of the manufacturing method of the functional fiber of this invention is explained in full detail. First, as the polyacrylonitrile-based polymer, a homopolymer or a copolymer with a known monomer can be used, but acrylonitrile (hereinafter also referred to as AN) is used for both of the two types of polymers that are mixed to form a fiber. It is desirable that the ratio is 60% by weight or more, more preferably 80% by weight or more. Also, the difference in the acrylonitrile content of the two types of polymers requires a certain degree of difference in the respective densification conditions in order to make one porous layer and the other dense layer under the same spinning conditions. It is preferable that the difference is 1% by weight or more, preferably 2% by weight or more.

The comonomer used for copolymerization is not particularly limited as long as it is copolymerizable with acrylonitrile, such as a polymerizable unsaturated vinyl compound. For example, alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, methacrylonitrile, acrylamide, chloride Vinyl, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene bromide, styrene, styrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonate, allyl sulfonate, methallyl sulfonate, ethylene, Propylene or the like can be used.

As a method of forming a fiber by mixing the two kinds of acrylonitrile polymers as described above, after dissolving two kinds of acrylonitrile polymers individually in a solvent of polyacrylonitrile, the polymer solution is subjected to specific spinning. Examples thereof include a method of introducing a side-by-side type into an apparatus / die, and a method of introducing a random composite type by introducing two types of polymer solutions into a spinning die through an undiluted multilayer forming apparatus. Above all, the random composite type is recommended because it can obtain a fiber having a multilayer structure exceeding two layers. The metal oxide fine particles having photocatalytic activity are added to the polymer solution on the dense layer side or added to the polymer to prepare a spinning dope.

Such a random composite type acrylic fiber is manufactured, for example, as follows. First, the respective polymers are dissolved in a solvent to obtain two spinning stock solutions (a, b). These two types of stock solutions a and b are guided to a stock solution multilayer forming apparatus. An example of such an apparatus is the registered trade name Kenics, which is a static mixer.
A mixer, an ISG mixer, and the like can be mentioned, and the apparatus sends the stock solution from the outlet side as the number of stock solution layers 2 to 10 times the number of stock solution layers on the supply side. The number of layers of the stock solution formed by using a plurality of such devices can be freely set.

A spinneret is mounted on the outlet side of the stock solution multilayer forming apparatus. When the stock solution formed in the n layer as a, b, a, b,... is supplied to a spinneret having a hole number H, the number of stock solution layers supplied to one hole of the spinning hole is on average. It is proportional to n / H ^0.5 . The proportionality coefficient depends on the apparatus conditions such as the stock solution multilayer forming apparatus, the shape of the spinneret (arrangement of spinning holes), the direction of attachment of the base, and so on, depending on the number of layers required for the cross section of one fiber These conditions are met.

The spinning dope discharged from the spinneret is subjected to coagulation, water washing and stretching processes, followed by wet heat treatment. At this time, solidification conditions and wet heat treatment conditions are set so that one is a dense layer and the other is a porous layer. In addition, the wet heat treatment here means a treatment in which heating is performed in an atmosphere of saturated steam or superheated steam. Thereafter, the functional fiber according to the present invention is obtained by drying at a temperature at which the porous layer is not densified.

  Even if the AN content is the same, the function of the present invention can be achieved by using different comonomers so that, for example, one comonomer of one AN polymer is hydrophilic and the other is hydrophobic. Can be obtained.

  The functional fiber of the present invention thus obtained contains metal oxide fine particles having photocatalytic activity in a dense layer of a multilayer structure fiber in which a porous layer and a dense layer are alternately arranged. Therefore, it is considered that the porous layer has an excellent function by adsorbing malodorous components and bacteria in the air and decomposing by the metal oxide having photocatalytic activity of the dense layer in contact with the porous layer. . Furthermore, since the metal oxide fine particles having photocatalytic activity are contained in the dense layer, the fine particles can be prevented from falling off during dyeing, and have excellent washing durability. In addition, it is possible to suppress deterioration of spinnability and dyeability due to generation of static electricity caused in the case of a fiber having only a porous layer.

EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to an Example. In the following examples, “%” or “part” means “% by weight” or “part by weight” unless otherwise specified. The evaluation test methods used in the examples and comparative examples are as follows.

(Deodorization performance evaluation)
A sample cotton (0.1 g) was put in a 1.5 L Tedlar bag (registered trademark), and acetaldehyde gas was put therein so as to have an initial concentration of 50 ppm by volume. Ultraviolet rays were irradiated at a distance of 20 to 30 cm from a Tedlar bag (registered trademark) using a light source in which two black light fluorescent lamps with reflectors (Matsushita Electric Industrial Co., Ltd., 20 watt type FL20S / BLB) were attached in parallel. The distance from the light source was adjusted so that the ultraviolet intensity was 0.25 mW / cm ² using an ultraviolet intensity meter. After irradiation with ultraviolet rays for 20 hours, the residual acetaldehyde gas concentration in the Tedlar bag (registered trademark) was measured with an acetaldehyde detector tube, and the residual gas deodorization rate (%) was calculated according to the following formula.
Gas deodorization rate (%) = [(initial concentration−residual gas concentration) / initial concentration] × 100
In the same manner, each residual gas concentration was measured under the conditions of ammonia gas initial concentration 300 volume ppm, acetic acid gas initial concentration 100 volume ppm, hydrogen sulfide gas initial concentration 15 volume ppm, and trimethylamine gas initial concentration 80 volume ppm. The gas deodorization rate (%) was calculated in the same manner as described above.

(Antimicrobial test)
Test strain: Staphylococcus aureus
ATCC 6538P
Test method: In accordance with a method defined by the Textile Products Sanitary Processing Council (SEK), a bouillon suspension of a test bacterium is poured into a sterilized sample cloth and irradiated with ultraviolet rays in a sealed container at 37 ° C. for 18 hours (180 to 200 μW / cm ² ), and the number of viable bacteria after the cultivation was measured. From the number B of the standard cloth and the number C of the sample cloth by the same test for the inoculated number A, the bacteriostatic activity value = (log B− The bacteriostatic activity value calculated | required by the formula of logA)-(logC-logA) is used. Generally, if the bacteriostatic activity value is 2.2 or more, it is considered that there is antibacterial performance, but 3.0 or more is preferable. In addition, in order to evaluate washing durability, the thing after 10 times of washing was used for the sample cloth. The washing method is as follows.

(Washing method)
Washing conditions According to JIS-L-0213 method 103 (for household washing machines), washing is repeated using Monogen Uni manufactured by Daiichi Kogyo Seiyaku Co., Ltd. as a detergent (10 times).

(Pore surface area evaluation)
Cut the fibers 10mg to short fibers, it was evaluated by Shimadzu MICROMERITICS Auto Pore IV to mercury pressure ^{4.14 × 10 -2 ~4.14 × 10 2} MPa. Since the obtained pore surface area (A1) includes inter-fiber voids, the pore surface area of the fiber was determined by subtracting the inter-fiber void (A2) according to the following formula.
Fiber pore surface area = A1-A2
A1: pore surface area of the mercury pressure ^{4.14 × 10 -2 ~4.14 × 10 2} MPa A2: pore surface area of the mercury pressure 4.14 × ¹⁰ -2 ~1.38MPa

(Evaluation of the number of multilayered layers)
After 200 fibers were drawn and hardened with wax, a thin sample with a thickness of 50 nm was prepared in the fiber cross-sectional direction using a microtome 2065 manufactured by Leica. The prepared flake sample was observed with an optical microscope AFX-II manufactured by Nikon, the number of layers per fiber was counted, and the average number of 200 layers was defined as the number of multilayered layers. Note that the number of layers can be more easily counted by thinly coloring the thin sample with a dye or the like.

Example 1
Spinning stock solution (I) composed of acrylonitrile copolymer consisting of acrylonitrile, methyl acrylate, sodium methallyl sulfonate and 90% by weight acrylonitrile content, and acrylonitrile content percentage consisting of acrylonitrile, methyl acrylate, sodium methallyl sulfonate A spinning stock solution (II) consisting of 88% by weight of acrylonitrile copolymer and titanium oxide fine particles (TK522 manufactured by Teika Co., Ltd.) having an average primary particle size of 15 nm in an ISG Mixer (theoretical stock solution layer number 432) at a ratio of 1: 1. The mixture was supplied, mixed and mixed, and subjected to wet spinning through a spinneret having 29221 holes. Here, a sodium rhodanate aqueous solution was used as a solvent for the acrylonitrile copolymer. The titanium oxide fine particles were adjusted to 5% by weight with respect to 100 parts by weight of the acrylonitrile polymer of the spinning dope (II).
As the coagulation liquid, a 12% by weight sodium rhodate aqueous solution was used at 1.5 ° C. Next, washing with water and hot drawing are performed, and the obtained fiber is subjected to steam treatment at 115 ° C. in a relaxed state without drying, and further dried at 110 ° C. for 15 minutes to be a random composite type acrylic fiber. Fiber was obtained. Furthermore, the functional fiber obtained was dyed in accordance with a conventional method using Maxilon Blue GRL300 manufactured by CIBA GEIGY to obtain a functional fiber for evaluation.

About the functional fiber for evaluation obtained in Example 1, when the gas deodorization rate with respect to each malodor component was evaluated, the deodorization rate was 100 in all of acetaldehyde gas, ammonia gas, acetic acid gas, hydrogen sulfide gas, and trimethylamine gas. %Met. The pore surface area and the number of multilayered layers are shown in Table 1.

As is clear from the results in Table 1, the deodorant fiber according to Example 1 is a dense layer of multilayer structure fiber in which metal oxide fine particles having photocatalytic activity are alternately arranged with a porous layer and a dense layer. Since it is contained, it is possible to effectively utilize the photocatalytic function and effectively decompose and deodorize various types of bad odors.

(Comparative Example 1)
Instead of the spinning stock solution (II) of Example 1, a spinning stock solution (III) comprising an acrylonitrile copolymer having an acrylonitrile content of 88% by weight comprising acrylonitrile, methyl acrylate and sodium methallyl sulfonate was used. Evaluation fibers were obtained in the same manner as in Example 1.

(Comparative Example 2)
Instead of the spinning dope (I) used in Example 1, an acrylonitrile copolymer consisting of acrylonitrile, methyl acrylate and sodium methallyl sulfonate having an acrylonitrile content of 90% by weight and fine titanium oxide particles having an average primary particle size of 15 nm The same as in Example 1, except that the spinning stock solution (IV) made of (TK522 manufactured by Teika Co., Ltd.) was used and the spinning stock solution (III) was used instead of the spinning stock solution (II) used in Example 1. The fiber for evaluation was obtained by the method. The titanium oxide fine particles were adjusted to 5% by weight with respect to 100 parts by weight of the acrylonitrile polymer of the spinning dope (IV).

(Comparative Example 3)
An evaluation fiber was obtained in the same manner as in Example 1 except that the spinning dope (II) was used instead of the spinning dope (I) used in Example 1.

(Comparative Example 4)
An attempt was made to produce fibers by the same method as in Comparative Example 2 except that the spinning dope (IV) was used in place of the spinning dope (II) used in Comparative Example 2, but the fibers were brittle due to insufficient heat drawing. Since it was only obtained, the evaluation fiber could not be obtained.

About each fiber obtained in Example 1 and Comparative Examples 1-3, the acetaldehyde gas deodorization rate, the pore surface area, and the number of multilayered layers were evaluated, and the results are shown in Table 1.

As is clear from the results in Table 1, in Comparative Example 1, since the titanium oxide fine particles having photocatalytic activity were not contained in the fiber, sufficient deodorizing performance could not be obtained. In Comparative Example 2, since the titanium oxide fine particles having photocatalytic activity were contained in the porous layer, the fine particles dropped off during dyeing, and sufficient deodorizing performance was not obtained. Further, in Comparative Example 3, since the whole was a dense layer, the adsorption ability of malodorous components was poor and sufficient deodorizing performance could not be obtained.

(Example 2)
Functional fibers for evaluation were obtained in the same manner as in Example 1 except that 12% by weight sodium rhodanate was used as the coagulation liquid at 5 ° C.

(Example 3)
For evaluation in the same manner as in Example 1, except that titanium oxide fine particles having an average primary particle diameter of 5 nm (titanium oxide AMT100 manufactured by Teika Co., Ltd.) are used in place of the titanium oxide TK522 manufactured by Teika Co., Ltd. used in Example 1. Of functional fibers.

Example 4
For evaluation in the same manner as in Example 1 except that titanium oxide fine particles (titanium oxide AMT600 manufactured by Teika Co., Ltd.) having an average primary particle diameter of 30 nm are used in place of the titanium oxide TK522 manufactured by Teika Co., Ltd. used in Example 1. Of functional fibers.

(Example 5)
In place of the spinning dope (II) used in Example 1, the spinning dope (V) adjusted such that the titanium oxide fine particles were 1 part by weight with respect to 100 parts by weight of the acrylonitrile copolymer in the spinning dope (II). The functional fiber for evaluation was obtained by the same method as in Example 1 except that (1) was used.

The functional fiber for evaluation obtained in Examples 2 to 5 was evaluated for acetaldehyde gas deodorization rate, and the results are also shown in Table 1.

As is clear from the results of the table, the functional fibers of Examples 2 to 5 showed better acetaldehyde gas deodorization rate than those of Comparative Examples 1 to 3. However, the functional fiber of Example 2 was prone to static electricity due to carding during spinning, etc., and was inferior in processability such as spinning, but had excellent deodorizing performance, temperature and humidity during processing, or It was sufficiently practical by optimizing the mixing ratio. Further, in preparing the functional fiber of Example 3, when preparing an aqueous dispersion of titanium oxide fine particles, the titanium oxide fine particles are likely to become dust, and it is necessary to wear a dust mask or the like. Although there were some problems in workability and productivity, such as being difficult to disperse to primary particles and requiring a considerable amount of time for dispersion, it had excellent deodorizing performance.

(Example 6)
The functional fiber obtained in Example 1 was blended with ordinary 3.3 dtex acrylonitrile fiber (Toyobo Co., Ltd. Exlan K8-3.3) at a ratio of 50% by weight to 50% by weight according to a conventional method, A 48th-ply spun yarn was produced and formed into a knitted fabric with 12 gauge 2 plies. When the antibacterial activity was evaluated using such a knitted fabric as a sample fabric, the bacteriostatic activity value was 4.6, indicating an excellent antibacterial property.

(Example 7)
The functional fiber obtained in Example 2 was blended with ordinary 3.3 dtex acrylonitrile fiber (Toyobo Co., Ltd. Exlan K8-3.3) at a ratio of 40% by weight to 60% by weight according to a conventional method, A 48th-ply spun yarn was produced and formed into a knitted fabric with 12 gauge 2 plies. When the antibacterial activity was evaluated using such a knitted fabric as a sample fabric, the bacteriostatic activity value was 4.6, indicating an excellent antibacterial property.

Claims (6)

A functional fiber, which is a multilayer structure fiber in which a porous layer and a dense layer are alternately arranged, and metal oxide fine particles having photocatalytic activity are contained in the dense layer. The functional fiber according to claim 1, wherein the pore surface area of the fiber is in the range of 10 to 40 m ² / g. The functional fiber according to claim 1 or 2, wherein the metal oxide fine particles are titanium oxide. The functional fiber according to any one of claims 1 to 3, wherein the particle diameter of the metal oxide fine particles is in the range of 10 to 100 nm. The functional fiber according to any one of claims 1 to 4, wherein 1 to 10 parts by weight of metal oxide fine particles are contained with respect to 100 parts by weight of the base of the fiber. The functional fiber according to any one of claims 1 to 5, wherein the functional fiber is a multilayer structure fiber made of an acrylonitrile-based polymer.