Photocatalyst-containing fiber

Abstract

To provide a photocatalyst-containing fiber capable of effectively removing an odor under visible light.SOLUTION: A photocatalyst-containing fiber 10 contains fibers 12, titanium oxide particles 14, and zinc oxide particles 16. The titanium oxide particle 14 and the zinc oxide particle 16 which are a photocatalytic particle are kneaded into the fiber 12 during manufacture. The average diameter of the titanium oxide particle 14 and the zinc oxide particle 16 is 0.1 to 1.0 microns. The weight ratio of the titanium oxide particles 14 to the total weight of the titanium oxide particles 14 and the zinc oxide particles 16 is 10 to 40%. The total weight of the titanium oxide particles 14 and the zinc oxide particles 16 is 1 to 6% based on the fiber weight.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a photocatalyst-containing fiber. [Background technology]

[0002] In recent years, there has been growing interest in odors that occur in all areas of human activity, including homes, schools, workplaces, hospitals, and sports scenes. As a result, there is a demand for textile products that can reduce or eliminate odors from ammonia, acetic acid, isovaleric acid (3-methylbutanoic acid), nonenal, formaldehyde, skatole, and other odors that are widely present in the living environment.

[0003] For example, the following Patent Document 1 discloses a textile product with a deodorizing effect that is coated with a visible light responsive photocatalyst. It is described in Patent Document 1 that by using titanium oxide of anatase type and amorphous crystal structure as the visible light responsive photocatalyst and containing a very small amount of vanadium and one or more transition metals or heterogeneous elements in the crystal, the function can be expressed with little energy.

[0004] However, Patent Document 1 explains that it reacts with ultraviolet light, but uses incandescent light, so there are some parts that raise doubts about its actual effectiveness. Also, because photocatalyst particles are contained in the coating agent, the photocatalyst will peel off when the coating agent peels off, and the deodorizing function will be lost. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-209200 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a photocatalyst-containing fiber that can effectively remove odors under visible light. [Means for solving the problem]

[0007] The photocatalyst-containing fiber of the present invention comprises a fiber, titanium oxide particles contained in the fiber, and zinc oxide particles contained in the fiber, wherein the average particle size of the titanium oxide particles and the zinc oxide particles is 0.1 to 1.0 microns, the weight ratio of the titanium oxide particles to the total weight of the titanium oxide particles and the zinc oxide particles is 10 to 40%, and the total weight of the titanium oxide particles and the zinc oxide particles is 1 to 6% of the fiber weight. Effect of the Invention

[0008] According to the present invention, various odors, such as sweat odor, sock odor, aging odor, cigarette odor, feces and urine odor, food odor, etc., can be efficiently deodorized. The photocatalyst-containing fiber of the present invention can be used to provide textile products having a deodorizing function that can remove the above-mentioned odors. For example, it can be used in clothing, indoor textile products, vehicle interior textile products, wallpaper, partitions, sheets, futon covers, etc. to remove various odors. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the structure of a photocatalyst-containing fiber of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The photocatalyst-containing fiber of the present invention will now be described in detail.

[0011] [composition] The photocatalyst-containing fiber 10 of the present invention includes fiber 12, titanium oxide particles 14, and zinc oxide particles 16 (Figure 1). The photocatalyst particles, titanium oxide particles 14 and zinc oxide particles 16, are kneaded into the fiber 12 during production. Since no coating agent is used as in the conventional technology, it is possible to prevent the photocatalyst particles from peeling off and losing their deodorizing function.

[0012] [fiber] The fiber 12 is a fiber containing at least one of polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polypropylene, polyacrylonitrile, polyvinyl alcohol, etc. The fiber 12 includes polyester fiber, polyolefin fiber, acrylic fiber, aramid fiber, vinylon fiber, and particularly polyester fiber is preferred. In the case of polyester fiber, it is a single or composite of polyethylene terephthalate, polybutylene terephthalate or polytetramethylene terephthalate. In the case of a composite, there are core-sheath type, side-by-side type, and sea-island type, and all are effective as the fiber 12 of the present invention. In the case of the core-sheath type, it is preferable to knead titanium oxide particles 14 and zinc oxide particles 16 into the sheath part. In the case of the side-by-side type and the sea-island type, they may be kneaded into the polymer.

[0013] When kneading photocatalyst particles into polyester fiber, either the masterbatch method or the direct kneading method of injecting into the extruder immediately before spinning can be applied. In the masterbatch method, the resin serving as the base of the masterbatch can be appropriately selected. The same polyester polymer as the fiber 12 may be used, or a polyester polymer having a different composition and degree of polymerization may be used. Polymers having different compositions include polymers copolymerized with a third component, polymers kneaded with inorganic substances other than photocatalyst particles, etc. In the case of the masterbatch method, when spinning the fiber, the chips of the masterbatch and the chips of the fiber body are mixed and supplied to the melt spinning system.

[0014] The fiber 12 may be either a long fiber or a short fiber. In the case of a long fiber, the production of multifilament is relatively easy. For example, 84 dtex 72 filaments are thin fibers, and the area of the photocatalyst particles appearing on the surface becomes wide, which is advantageous for the deodorizing performance.

[0015] It is difficult to manufacture short fibers thinner than long fibers, but they are cut to 38 mm or so, and the photocatalyst particles that appear on the cut surface are used for deodorization. The thickness of short fibers is preferably 0.5 decitex to 2.5 decitex, and more preferably 1.0 decitex to 2.0 decitex. If it is less than 0.5 decitex, spinning breakage is likely to occur. If it exceeds 2.5 decitex, the fiber surface area per unit weight becomes smaller, making it difficult to achieve deodorizing performance.

[0016] The breaking strength of the fiber 12 is 2.0 cN / dtex or more and 5.0 cN / dtex or less. The breaking elongation of the fiber 12 is 30% or more and 90% or less, and more preferably 40% or more and 80% or less. Since the elongation of polyester staple fibers is generally adjusted to be lower than about 30%, the staple fiber of the present invention has a higher elongation than usual. A higher elongation means a lower draw ratio, which suppresses the orientation of polymer chains due to drawing to a certain extent and makes the amorphous portion larger than usual, thereby increasing the opportunity for the photocatalyst to come into contact with odorous gases and enhancing the deodorizing effect.

[0017] [Photocatalyst particles] The titanium oxide particles 14 are classified into anatase type and rutile type according to the crystal form, and the anatase type is used in the present invention.

[0018] The titanium oxide particles 14 and zinc oxide particles 16 may have a surface coating of an inorganic substance, for example, apatite or alumina. If the photocatalyst-containing fiber 10 is used in an environment where it is irradiated with ultraviolet light, the coating can slow down the degradation rate of the polymer substrate. If the photocatalyst-containing fiber 10 is used in an environment where it is not irradiated with ultraviolet light, the coating is not necessary.

[0019] The average particle size of the titanium oxide particles 14 and the zinc oxide particles 16 is 0.1 microns or more and 1.0 microns or less. The average particle size is a volume average particle size. For example, even if the average particle size is 0.2 microns, the cumulative particle size distribution is D 10 = 0.09 microns, D 50 = 0.18 microns, D90 = 1.36 microns, and may contain particles both smaller and larger than the average particle size.

[0020] Generally, photocatalyst particles are less than 0.1 microns, but a smaller average particle size is undesirable because it increases manufacturing costs and causes secondary aggregation. Also, an average particle size exceeding 1.0 microns is undesirable because the surface area per weight is small and the deodorizing effect is reduced. Furthermore, an average particle size exceeding 1.0 microns results in an increase in coarse particles, which are filtered through a spinning filter during spinning, but are undesirable because the spinning filter becomes clogged in a short time and productivity decreases.

[0021] The average particle size of the titanium oxide particles 14 is from 0.1 micron to 1.0 micron, preferably from 0.4 micron to 1.0 micron. The average particle size of the zinc oxide particles 16 is from 0.1 micron to 0.8 micron, preferably from 0.1 micron to 0.5 micron. It is preferable that the average particle size 16 of the zinc oxide particles 14 is relatively smaller than the average particle size of the titanium oxide particles.

[0022] Furthermore, when the average particle size of the titanium oxide particles 14 is A and the average particle size of the zinc oxide particles 16 is B, it is preferable that B / A is 0.5 or less. It is preferable that the average particle size of the zinc oxide particles 16 is ½ or less of the average particle size of the titanium oxide particles 14. It is considered that the coexistence of the titanium oxide particles 14 and the zinc oxide particles 16, which have different average particle sizes, allows the incident light to be trapped for a long time in a complex particle structure rather than being immediately reflected and released out of the system, and the photocatalyst particles are excited by visible light.

[0023] The weight ratio of the titanium oxide particles 14 to the total weight of the titanium oxide particles 14 and the zinc oxide particles 16 is 10% or more and 40% or less, and preferably 10% or more and 33% or less.

[0024] The kneading amount of titanium oxide particles 14 and zinc oxide particles 16 into the fiber 12 is 1.0 wt% or more and less than 6.0 wt% with respect to the fiber 12, preferably 2.5 wt% or more and less than 5.0 wt%. If it is less than 1.0 wt%, the deodorizing effect is small, and if it is 6.0 wt% or more, it is not preferable because thread breakage frequently occurs in the melt spinning process of the fiber 12, for example, polyester fiber.

[0025] [Other materials] In the present invention, a metal oxide or a glassy substance having no photocatalytic effect may be contained in the fiber 12. The dispersibility of the photocatalytic particles may be improved by containing these substances in the fiber 12. This is presumably because the apparent surface area of the photocatalyst increases.

[0026] [Fiber products using photocatalyst-containing fibers] A plurality of photocatalyst-containing fibers 10 are used to form a thread, and the thread is used for woven fabrics, knitted fabrics, non-woven fabrics, and other fiber products. Since the deodorizing function of the photocatalyst-containing fiber 12 exhibits excellent deodorizing properties against odors such as ammonia, acetic acid, isovaleric acid, formaldehyde, hydrogen sulfide, nonenal, and raw laundry odor, it can be used for various applications. For example, the photocatalyst-containing fiber of the present invention can be used for fibers used in various products, including underwear, sportswear, work clothes, bedding such as sheets and pillowcases, household fiber products such as curtains and wallpapers, and various fiber products used in hospitals and nursing facilities.

[0027] Woven fabrics and knitted fabrics go through a dyeing finishing process, but the photocatalyst-containing fiber 10 of the present invention has photocatalytic particles kneaded into the fiber 12 and exhibits a deodorizing function even after undergoing dry heat setting at around 200 °C, high-pressure dyeing at 130 - 135 °C, and subsequent alkali reduction washing. Since the kneading amount of the photocatalytic particles is relatively small, it hardly affects the dyeing of the fiber 12.

[0028] In a textile product using the photocatalyst-containing fiber 10, the mixing ratio is usually 10 to 40%, but the mixing ratio may be changed depending on the amount of the photocatalyst particles kneaded. This mixing ratio may be appropriately changed depending on the intended use of the textile product. For example, a 28-gauge circular knitted jersey made of a 32-count ring-spun yarn consisting of 20% polyester staple fiber with 2.2% photocatalyst particles and 80% polyester staple fiber without photocatalyst particles is suitable as a sports shirt and has an excellent deodorizing function. The mixing ratio of the photocatalyst-containing fiber 10 of the present invention in this shirt is 20%.

[0029] Similarly, a taffeta (plain weave) using a polyester filament 84 dtex 48 filament without photocatalyst particles for the warp and a polyester filament 84 dtex 72 filament with 2.5% photocatalyst particles for the weft can provide an excellent deodorizing function in a hospital ward when used as a partition in a hospital facility or the like. In this case, the mixing ratio of the photocatalyst-containing fiber 10 of the present invention is 40%.

[0030] Note that the photocatalyst-containing fiber 10 of the present invention may be used as a single fiber in various fabrics and the like.

[0031] [Manufacturing method] Next, a method for manufacturing the photocatalyst-containing fiber 10 and a yarn using the fiber 10 will be described. (1) The raw material of the chip-shaped fiber 12 is heat-melted in a melting device. (2) The above-described photocatalyst particles are mixed into the melted raw material of the fiber 12. In this step, the photocatalyst particles may be mixed into the raw material before putting the raw material of (1) into the melting device. (3) The melted material mixed with the photocatalyst particles is put into a spinning device, and the put-in material is extruded from small holes of the spinning device to form a photocatalyst-containing fiber.

[0032] Thereafter, when making staple fibers using the photocatalyst-containing fiber 10, a plurality of photocatalyst-containing fibers 10 are gathered, stretched by a plurality of rollers, crimped by a crimping device, and finally cut by a cutting device. Also, when making filaments, the photocatalyst-containing fiber 10 is stretched and wound up.

[0033] Although the above-mentioned production method is melt spinning, it may be produced by wet spinning or dry spinning.

[0034] [Example] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples described. The photocatalyst-containing fiber in each example is a polyester fiber containing a photocatalyst. For comparison, polyester fibers containing only titanium oxide particles or zinc oxide particles were produced.

[0035] [Example 1] The titanium oxide particles are of the anatase type and have a cumulative particle size distribution D 10 , D 50 and D. 90 The particle sizes of the zinc oxide particles were 0.325 microns, 0.504 microns, and 4.121 microns, respectively, and the volume average particle size was 0.894 microns. 10 , D 50 and D. 90 The particle sizes of the titanium oxide particles and zinc oxide particles were 0.093, 0.177, and 0.676 microns, respectively, and the volume average particle size was 0.205 microns. A powder of titanium oxide particles and zinc oxide particles mixed in a weight ratio of 25:75 was added directly to the extruder just before spinning. The photocatalyst particles mixed with the spun polymer were 2.25% by weight. Polyester staple fiber was produced by conventional spinning, drawing, and cutting. The fiber had a thickness of 1.67 decitex, a cut length of 38 mm, a breaking strength of 3.7 g / dtex, a breaking elongation of 46%, and a circular cross section.

[0036] [Example 2] The anatase type titanium oxide particles with a volume average particle size of 0.894 microns and zinc oxide particles with a volume average particle size of 0.205 microns used in Example 1 were used. A powder mixture of titanium oxide particles and zinc oxide particles in a weight ratio of 35:65 was added to the extruder immediately before direct spinning. The photocatalyst particles mixed into the spun polymer were 2.25% by weight. Polyester staple fiber was produced by normal spinning, drawing, and cutting. The fiber had a thickness of 1.67 decitex, a cut length of 38 mm, a breaking strength of 3.5 g / dtex, a breaking elongation of 42%, and a circular cross section.

[0037] [Example 3] Anatase-type titanium oxide particles with a volume average particle size of 0.670 microns and zinc oxide particles with a volume average particle size of 0.255 microns were mixed in a weight ratio of 30:70. The mixed powder was mixed with polyethylene terephthalate chips with an intrinsic viscosity [η] = 0.52 and further added to an extruder to create a master batch containing 20% ​​by weight of photocatalyst particles. 15 parts of this master batch and 85 parts of polyethylene terephthalate chips with an intrinsic viscosity [η] = 0.58 were introduced into the extruder of a polyester filament spinning device, and polyester filament POY with a round cross section was spun at 3500 m / min. After that, it was stretched and false-twisted to produce a two-heater false-twisted textured yarn with 84 decitex and 48 filaments.

[0038] [Comparative Example 1] The anatase type titanium dioxide particles with a volume average particle size of 0.894 microns used in Example 1 were added to the extruder directly before spinning. The titanium dioxide particles were 2.25% by weight relative to the spun polymer. Polyester staple fiber was produced by normal spinning, drawing, and cutting. The fiber had a thickness of 1.67 decitex, a cut length of 38 mm, a breaking strength of 4.0 g / dtex, a breaking elongation of 40%, and a circular cross section.

[0039] [Comparative Example 2] The zinc oxide particles used in Example 1 had a volume average particle size of 0.205 microns. The zinc oxide particles were added directly to the extruder just before spinning. The zinc oxide particles were 2.25% by weight relative to the spun polymer. Polyester staple fiber was produced by conventional spinning, drawing, and cutting. The fiber had a thickness of 1.67 decitex, a cut length of 38 mm, a breaking strength of 4.8 g / dtex, a breaking elongation of 48%, and a circular cross section.

[0040] The deodorizing performance of the fibers produced in the above Examples and Comparative Examples was evaluated under the following conditions.

[0041] [Sample preparation] Before measuring the deodorizing performance of the samples of the above examples and comparative examples, a solution containing 1 g / l of a nonionic surfactant in distilled water was used, and 5 grams of sample per 1 liter of solution was stirred in a beaker at 90° C. for 20 minutes. After that, the sample was washed twice with distilled water at 60° C. for 20 minutes, dehydrated, and naturally dried, and allowed to reach a constant weight for more than 24 hours in an environment of 20° C. and 65% HR.

[0042] [Measurement environment] A darkroom was used as the room for measuring the deodorizing performance. The lamps installed in the darkroom were visible light lamps that emitted light of blue, green, and pink wavelengths, and an ultraviolet lamp. The following lamps were used. Measurements were made with any of the lamps turned on or with all the lamps turned off. The distance between the lamp and the sample was 5 cm, and the temperature of the darkroom was 20°C and 65RH%. Ultraviolet lamp: FL15BL (15W, manufactured by NEC) Visible blue light lamp: FL20SB (20W, manufactured by NEC) Visible green lamp: FL20G (20W, manufactured by NEC) Visible pink light lamp: FL20SPK (20W, manufactured by NEC)

[0043] [measurement] A sample was placed in a 300 ml Pyrex (registered trademark) Erlenmeyer flask, and a standard concentration of odorous gas was injected and sealed. Gas was collected from the flask 2 hours and 6 hours after gas injection, and the gas concentration was measured using a detector (detector tube) appropriate for the type of gas. Measurements were performed three times, and the average value was taken. The sample thread for each example and comparative example was 0.3 g, and the following gases were used. Ammonia odor: 1.4% ammonia aqueous solution 5μl Formalin odor: 3.7% formaldehyde aqueous solution 5μl Isovaleric acid odor: 10% isovaleric acid aqueous solution 5μl

[0044] [Blank test] A blank test was conducted by placing a sample in a 300 ml Pyrex (registered trademark) Erlenmeyer flask in a dark room at 26°C and 65% RH, and injecting a standard concentration of odorous gas.

[0045] [Deodorizing rate] After each time elapsed, the amount of deodorization reduced by the test specimen irradiated with ultraviolet and visible light was expressed as a percentage compared to the remaining gas concentration in the blank test. For example, if the gas concentration of the blank is 80 ppm and the gas concentration of the UV-irradiated sample is 10 ppm, the deodorization rate is ((80-10) / 80) x 100 = 87.5%.

[0046] [Deodorizing performance evaluation] In the table below, deodorizing performance is shown as "good" with a deodorizing rate of 70% or more, and as "△" with a deodorizing rate of 60% or more but less than 70%. Deodorizing performance of less than 60% is judged as "no deodorizing performance" and is shown as "x".

[0047] [Ammonia deodorizing properties] Table 1 shows the ammonia deodorizing properties of the fibers of Example 1 and Comparative Example 1 when irradiated with each type of light. Comparative Example 1 only had limited deodorizing properties under ultraviolet light and did not exhibit deodorizing properties under visible light. On the other hand, Example 1 of the present invention, which contained titanium oxide particles and zinc oxide particles, had improved deodorizing performance in all cases compared to Comparative Example 1.

[0048] [Table 1]

[0049] [Formaldehyde deodorizing properties] Table 2 shows the deodorizing performance against formaldehyde of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Comparative Example 1 and Comparative Example 2 had limited deodorizing properties under ultraviolet light, but did not show deodorizing properties under visible light. On the other hand, Example 1 and Example 2 showed a certain deodorizing property after 2 hours, and showed deodorizing properties at any wavelength after 6 hours. In addition, it was found that the deodorizing rates after 2 hours for Example 1 and Example 2 were better for Example 1 than for Example 2, and that Example 1 showed deodorizing properties in a shorter time than Example 2. It was found that the deodorizing properties differed depending on the mixing ratio of titanium oxide particles and zinc oxide particles, and that the mixing ratio of Example 1 (25:75) was better than the mixing ratio of Example 2 (35:65).

[0050] [Table 2]

[0051] [Deodorizing properties of isovaleric acid] Table 3 shows the deodorizing properties against isovaleric acid in Example 2 and Comparative Example 2. It was found that Comparative Example 2 exhibits deodorizing properties against ultraviolet rays but not against visible light. On the other hand, it was found that Example 2 exhibits deodorizing properties against ultraviolet rays and visible light.

[0052] [Table 3]

[0053] [Deodorizing properties of polyester filaments] The deodorizing properties of the polyester long fiber of Example 3 are shown in Table 4. The figures indicate the deodorizing rate (%). Example 3 is a master batch type polyester long fiber processed yarn containing 3.0% of the above-mentioned two types of photocatalyst particles. It was found to have excellent deodorizing properties not only under ultraviolet light but also under visible light.

[0054] [Table 4]

[0055] In addition, the present invention can be implemented in various forms with various improvements, modifications, and changes based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0056] 10: Photocatalyst-containing fiber 12: Fiber 14: Titanium oxide particles 16: Zinc oxide particles

Claims

1. Fibers and anatase type titanium oxide particles contained in the fibers and having a surface coated with an inorganic substance; zinc oxide particles contained in the fibers and having a surface coated with an inorganic substance; Including, the titanium oxide particles and zinc oxide particles have an average particle size of 0.1 to 1.0 microns; the weight ratio of the titanium oxide particles to the total weight of the titanium oxide particles and the zinc oxide particles is 10 to 40%; the total weight of the titanium oxide particles and zinc oxide particles is 1 to 6% based on the fiber weight; When the average particle size of the titanium oxide particles is A and the average particle size of the zinc oxide particles is B, B / A is 0.5 or less, The deodorization rate of ammonia, formaldehyde and isovaleric acid is 70% or more after 6 hours of exposure to ultraviolet light, visible blue light, visible green light and visible pink light. Fiber containing photocatalyst.

2. 2. The photocatalyst-containing fiber according to claim 1, wherein the fiber is a short fiber having a thickness of 0.5 to 2.5 dtex, a breaking strength of 2.0 to 5.0 cN / dtex, and a breaking elongation of 30 to 90%.

3. A textile product using the photocatalyst-containing fiber of claim 1 or 2, wherein the blend ratio of the photocatalyst-containing fiber in said textile product is 10 to 40%.

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