Fiber, cloth and underwear

Abstract

To provide a fiber which radiates far-infrared rays having sufficient intensity even in clothing having a thin cloth, and can promote blood circulation of a wearer, a cloth containing the fiber and clothing.SOLUTION: A fiber is used in clothing. The fiber has a thermoplastic resin, and ceramic powder dispersed in the thermoplastic resin. The ceramic powder contains one or two or more kinds of first ceramic components selected from the group consisting of titania, titanium carbide and titanium boride, and one or two or more kinds of second ceramic components selected from the group consisting of zirconia, zirconium carbide and zirconium boride. A mass ratio of the first ceramic component in the ceramic powder is 40 mass% or more and 80 mass% or less, and a mass ratio of the second ceramic component in the ceramic powder is 10 mass% or more and less than 25 mass%. The content of the ceramic powder in the fiber exceeds 1.2 mass% and 1.8 mass% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to fibers, fabrics and underwear. [Background technology]

[0002] Ceramics have the property of absorbing far-infrared rays emitted by the human body and then emitting them back out as far-infrared rays. Therefore, by adding ceramics to the fibers that make up clothing, the far-infrared rays emitted from the ceramics can be irradiated onto the wearer, giving them a feeling of warmth and promoting their blood circulation.

[0003] For example, Patent Document 1 describes a far-infrared radiation material characterized by containing 60 to 90% by weight of at least one selected from titanium dioxide and titanium carbide, 10 to 40% by weight of at least one selected from silicon dioxide and silicon carbide, and 0.01 to 0.5% by weight of a rare earth metal oxide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-51896 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the far-infrared emitting material of Patent Document 1 is added to fibers and then clothing is made using these fibers, the intensity of far-infrared rays emitted from the clothing tends to be low. In particular, in the case of clothing made of thin fabric such as underwear, it is difficult to radiate far-infrared rays with sufficient intensity from the clothing, which poses a problem that the effect of promoting blood circulation in the wearer tends to be reduced.

[0006] The present invention has been made in view of the above background, and aims to provide a fiber that can radiate far-infrared rays of sufficient intensity even in clothing with thin fabric thickness, and can promote blood circulation in the wearer, as well as a fabric and clothing containing this fiber. [Means for solving the problem]

[0007] One aspect of the present invention is a fiber for use in clothing, comprising: A thermoplastic resin, and a ceramic powder dispersed in the thermoplastic resin, The ceramic powder contains one or more first ceramic components selected from the group consisting of titania, titanium carbide, and titanium boride; and one or more second ceramic components selected from the group consisting of zirconia, zirconium carbide, and zirconium boride; The mass ratio of the first ceramic component in the ceramic powder is 40 mass% or more and 80 mass% or less, The mass ratio of the second ceramic component in the ceramic powder is 10 mass% or more and less than 25 mass%, The content of the ceramic powder in the fibers is more than 1.2 mass % and not more than 1.8 mass %. [Effects of the Invention]

[0008] The content of the ceramic powder in the fiber is within the specified range. The ceramic powder contains the first ceramic component and the second ceramic component in a mass ratio within the specified range. Therefore, the fiber can efficiently absorb far-infrared rays emitted from the human body. As a result, even if the fabric is thin, it can emit far-infrared rays with sufficient intensity.

[0009] Therefore, according to the above-mentioned aspect, it is possible to provide a fiber that can emit far infrared rays of sufficient intensity even in clothing with thin fabric thickness and promote blood circulation in the wearer, as well as a fabric and clothing that include this fiber. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a graph showing the normal spectral emissivity of far-infrared rays of a measurement sample and a reference sample in Example 1. [Figure 2] FIG. 2 is a graph showing the difference in normal spectral emissivity in Example 1. [Figure 3] FIG. 3 is a graph showing the normal spectral emissivity of far-infrared rays of the measurement sample and the reference sample in Example 2. [Figure 4] FIG. 4 is a graph showing the difference in normal spectral emissivity in Example 2. [Figure 5] FIG. 5 is a graph showing the normal spectral emissivity of far-infrared rays of a measurement sample and a reference sample in Comparative Example 1. [Figure 6] FIG. 6 is a graph showing the difference in normal spectral emissivity in Comparative Example 1. [Figure 7] FIG. 7 is a graph showing the rate of change in blood flow when the test product was worn and the rate of change in blood flow when the control product was worn in Example 3. [Figure 8] FIG. 8 is a graph showing the rate of change in blood flow when the test product was worn and the rate of change in blood flow when the control product was worn in Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0011] (fiber) The fibers contain a thermoplastic resin and ceramic powder. The thermoplastic resin used for the fibers is not particularly limited, and any thermoplastic resin known for use in synthetic fibers, such as polyamide, polyester, or acrylic resin, can be used.

[0012] The ceramic powder is dispersed in a thermoplastic resin. The ceramic powder includes a first ceramic component and a second ceramic component. The ceramic powder may be composed of the first ceramic component and the second ceramic component, or may be composed of the first ceramic component, the second ceramic component, and a ceramic component other than these. An example of a ceramic component other than the first ceramic component and the second ceramic component is a third ceramic component, which will be described later.

[0013] The first ceramic component can be one or more ceramics selected from the group consisting of titania (TiO2), titanium carbide (TiC), and titanium boride (TiB2). The first ceramic component has the effect of absorbing far-infrared rays emitted from the human body and radiating them to the outside as far-infrared rays. In addition, by blending the first ceramic component into fibers, the gloss of the fiber surface can be eliminated. As a result, the glossiness of the fabric can be reduced.

[0014] The mass ratio of the first ceramic component in the ceramic powder is 40% by mass or more and 80% by mass or less. By making the mass ratio of the first ceramic component in the ceramic powder 40% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and particularly preferably 60% by mass or more, the intensity of far-infrared rays emitted from the fibers can be increased. If the mass ratio of the first ceramic component is less than 40% by mass, the intensity of far-infrared rays emitted from the fibers may be reduced.

[0015] On the other hand, if the mass ratio of the first ceramic component in the ceramic powder is too high, the contents of the other components will be insufficient, which may result in a decrease in the intensity of far-infrared rays emitted from the fibers. This problem can be easily avoided by setting the mass ratio of the first ceramic component in the ceramic powder to 80 mass% or less, preferably 77 mass% or less, more preferably 74 mass% or less, and even more preferably 71 mass% or less.

[0016] In determining a preferred range of the mass ratio of the first ceramic component in the ceramic powder, the above-mentioned upper and lower limits of the mass ratio of the first ceramic component can be combined arbitrarily. For example, the preferred range of the mass ratio of the first ceramic component may be 45% by mass to 77% by mass, 50% by mass to 74% by mass, 55% by mass to 71% by mass, or 60% by mass to 71% by mass.

[0017] From the viewpoint of more reliably obtaining the effects of the first ceramic component described above, the first ceramic component preferably contains titania, and from the same viewpoint, the first ceramic component is more preferably composed of titania.

[0018] The second ceramic component can be one or more ceramics selected from the group consisting of zirconia (ZrO2), zirconium carbide (ZrC), and zirconium boride (ZrB2). The second ceramic component has the effect of absorbing far-infrared rays emitted from the human body and radiating them to the outside as far-infrared rays. In addition, blending the second ceramic component into the fiber can improve the heat storage and heat insulation properties of the fiber. As a result, the heat storage and heat insulation properties of the fabric are improved, and even if the fabric is thin, it can efficiently absorb far-infrared rays emitted from the human body.

[0019] The mass ratio of the second ceramic component in the ceramic powder is 10% by mass or more and less than 25% by mass. By setting the mass ratio of the second ceramic component in the ceramic powder to 10% by mass or more, preferably 12% by mass or more, more preferably 14% by mass or more, and even more preferably 16% by mass or more, the fibers can efficiently absorb far-infrared rays emitted from the human body and the insulating and heat-retaining properties of the fabric can be improved. As a result, the intensity of far-infrared rays emitted from the fabric can be increased and the effect of promoting blood circulation in the wearer can be further improved. If the mass ratio of the second ceramic component is less than 10% by mass, this may result in a decrease in the efficiency of absorption of far-infrared rays emitted from the human body and a decrease in the heat-retaining and insulating properties of the fabric. As a result, the effect of promoting blood circulation in the wearer may be insufficient.

[0020] On the other hand, if the mass ratio of the second ceramic component in the ceramic powder is too high, the contents of the other components will be insufficient, which may actually result in a decrease in the intensity of the far-infrared rays emitted from the fibers. This problem can be easily avoided by setting the mass ratio of the second ceramic component in the ceramic powder to less than 25 mass%, preferably 24 mass% or less, more preferably 23 mass% or less, and even more preferably 22 mass% or less.

[0021] In determining a preferred range of the mass ratio of the second ceramic component in the ceramic powder, the above-mentioned upper and lower limits of the mass ratio of the second ceramic component can be combined arbitrarily. For example, the preferred range of the mass ratio of the second ceramic component may be 12% by mass or more and 224% by mass or less, 14% by mass or more and 23% by mass or less, or 16% by mass or more and 22% by mass or less.

[0022] From the viewpoint of more reliably obtaining the effects of the second ceramic component described above, the second ceramic component preferably contains zirconia, and from the same viewpoint, the second ceramic component is more preferably made of zirconia.

[0023] The ceramic powder may contain a third ceramic component different from the first and second ceramic components described above, such as one or more ceramics selected from the group consisting of silica (SiO), alumina (AlO), alkali metal oxides, alkaline earth metal oxides, and Group 8 metal oxides.

[0024] The mass ratio of the third ceramic component in the ceramic powder is preferably more than 0 mass% and not more than 20 mass%, more preferably 3 mass% to 18 mass%, and even more preferably 6 mass% to 16 mass%, in which case the effect of the third ceramic component can be obtained without impairing the effects of the first and second ceramic components.

[0025] By adding a third ceramic component to the ceramic powder, it is expected that an effect according to the type of the third ceramic component can be obtained.

[0026] For example, silica has the effect of absorbing far-infrared rays emitted from the human body and radiating them to the outside as far-infrared rays. Furthermore, by blending silica into fibers, the heat insulating properties of the fibers can be improved, and heat dissipation from the fabric to the outside can be suppressed. As a result, even if the fabric is thin, heat can be retained in the fabric, and the intensity of the far-infrared rays radiated from the fibers can be increased.

[0027] From the viewpoint of further enhancing this effect, the mass ratio of silica in the ceramic powder is preferably 1 mass% or more and 15 mass% or less, more preferably 3 mass% or more and 13 mass% or less, and even more preferably 5 mass% or more and 11 mass% or less.

[0028] Furthermore, for example, alumina has the effect of absorbing far-infrared rays emitted from the human body and radiating them to the outside as far-infrared rays. Furthermore, by blending alumina into fibers, the heat resistance and heat dissipation properties of the fibers can be improved.

[0029] From the viewpoint of further enhancing this effect, the mass ratio of alumina in the ceramic powder is preferably 1 mass% or more and 10 mass% or less, more preferably 1.5 mass% or more and 8 mass% or less, and even more preferably 2 mass% or more and 6 mass% or less.

[0030] From the viewpoint of increasing the intensity of far-infrared rays emitted from the fabric even when the fabric is thin and further enhancing the effect of promoting blood circulation in the wearer, the third ceramic component preferably contains at least one of silica and alumina, preferably contains both silica and alumina, and more preferably is composed of silica and alumina.

[0031] The content of ceramic powder in the fiber is more than 1.2% by mass and not more than 1.8% by mass. By increasing the content of ceramic powder to more than 1.2% by mass, the effect of improving the radiation intensity of far-infrared rays by the ceramic powder can be enhanced. On the other hand, if the content of ceramic powder is excessively high, the fiber may be easily torn during the production process, which may result in a decrease in productivity. By setting the content of ceramic powder in the fiber to not more than 1.8% by mass, such problems can be easily avoided. From the viewpoint of further enhancing the effect of improving the radiation intensity of far-infrared rays by the ceramic powder, the content of ceramic powder in the fiber is preferably not less than 1.3% by mass and not more than 1.8% by mass, more preferably not less than 1.4% by mass and not more than 1.8% by mass, and even more preferably not less than 1.5% by mass and not more than 1.8% by mass.

[0032] The median diameter (so-called D50) of the ceramic powder on a volume basis is preferably 100 nm or more and 500 nm or less. Ceramic powder with such a particle size distribution has excellent dispersibility in thermoplastic resins, so that uneven distribution of the ceramic powder within the fiber can be further reduced. Furthermore, in this case, problems such as thread breakage can be more easily avoided during the fiber manufacturing process. From the same perspective, the cumulative 90% diameter (so-called D90) of the ceramic powder on a volume basis is preferably 300 nm or more and 900 nm or less.

[0033] The fineness of the fiber is preferably 30 denier or more and 150 denier or less, more preferably 40 denier or more and 130 denier or less, and even more preferably 50 denier or more and 110 denier or less. Fabrics containing fibers of such fineness can more efficiently absorb far-infrared rays emitted from the human body. In this case, the fabric can be made thinner without impairing the far-infrared absorption efficiency, heat insulation, and heat storage properties. Furthermore, fabrics containing such fineness are soft to the touch and are therefore suitable for underwear. The above-mentioned fiber fineness is the mass of a 9000m length of fiber expressed in grams (g).

[0034] The method for producing the fiber is not particularly limited, and an appropriate method can be adopted from known fiber production methods. For example, when producing the fiber by melt spinning, a thermoplastic resin and a ceramic powder are first melt-kneaded using an extruder to produce a melt-kneaded mixture. The melt-kneaded mixture is extruded into a filamentous form through a die of the extruder to obtain the fiber. If necessary, the fiber thus obtained can be subjected to a drawing process or the like to adjust the fiber fineness.

[0035] The melt-kneading of the thermoplastic resin and the ceramic powder may be carried out in one stage or two stages. When the melt-kneading of the thermoplastic resin and the ceramic powder is carried out in two stages, the thermoplastic resin and the ceramic powder are first melt-kneaded to prepare a masterbatch, and then this masterbatch and the thermoplastic resin are melt-kneaded. From the viewpoint of further reducing the uneven distribution of the ceramic powder in the fiber, it is preferable to melt-knead the thermoplastic resin and the ceramic powder in two stages.

[0036] (Fabric) Fabrics made using the fibers can be made to have the ability to emit far-infrared rays. The fibers efficiently absorb far-infrared rays emitted from the human body and improve the insulation and heat storage properties of the fabric. Therefore, fabrics containing the fibers can easily increase the intensity of far-infrared rays emitted from the fabric, even when the fabric is thin, and can easily improve the effect of promoting blood circulation in the wearer.

[0037] The fabric may be made of only the above-mentioned fibers, or may be made of the above-mentioned fibers and other fibers, such as synthetic fibers that do not contain ceramic powder.

[0038] The mass ratio of the fibers in the fabric is preferably 10% by mass or more and 50% by mass or less. By setting the mass ratio of the fibers in the fabric to 10% by mass or more, the fabric can more efficiently absorb far-infrared rays emitted from the human body. As a result, the intensity of far-infrared rays emitted from the fabric can be more easily increased. On the other hand, if the mass ratio of the fibers in the fabric is excessively high, the fabric tends to become stiff, which may impair the texture and comfort. By setting the mass ratio of the fibers in the fabric to 50% by mass or less, such problems can be more easily avoided.

[0039] As mentioned above, the fabric containing the above-mentioned fibers can easily increase the intensity of far-infrared rays emitted from the fabric even when the fabric is thin, and can easily enhance the effect of promoting blood circulation in the wearer. 2 The mass per unit is preferably 100 g or more and 300 g or less, more preferably 130 g or more and 270 g or less, even more preferably 140 g or more and 230 g or less, particularly preferably 150 g or more and 210 g or less, and most preferably 175 g or more and 190 g or less.

[0040] The weave of the fabric is not particularly limited and may take various forms. For example, the weave of the fabric may take various forms such as plain weave, twill weave, satin weave, etc. When the fabric is used for underwear, from the viewpoint of the thinness and feel of the fabric, the weave of the fabric is preferably plain weave, and more preferably jersey knit.

[0041] (underwear) As described above, fabrics containing the above-mentioned fibers efficiently absorb far-infrared rays emitted from the human body and have excellent insulating and heat-storing properties. Therefore, even if the fabric is thin, fabrics containing the above-mentioned fibers can easily increase the intensity of far-infrared rays emitted from the fabric and easily enhance the effect of promoting blood circulation in the wearer. Therefore, by constructing underwear using fabrics containing the above-mentioned fibers, it is possible to effectively utilize the above-mentioned effects and obtain underwear that is highly effective in promoting blood circulation in the wearer.

[0042] The type of underwear is not particularly limited and may take various forms. For example, the underwear may be underwear worn on the upper body, such as a long-sleeved inner shirt or a short-sleeved inner shirt, or underwear worn on the lower body, such as leggings or boxer shorts. [Example]

[0043] Example 1 An example of the fiber is described below. The fiber of this example has polyester as a thermoplastic resin and ceramic powder dispersed in the thermoplastic resin. The ceramic powder contains titania as a first ceramic component, zirconia as a second ceramic component, and silica and alumina as a third ceramic component. The mass ratio of titania in the ceramic powder is 67 mass%, the mass ratio of zirconia is 20 mass%, the mass ratio of silica is 8 mass%, and the mass ratio of alumina is 5 mass%. The content of the ceramic powder in the fiber is 1.5 mass%. The fineness of the fiber of this example is 75 denier.

[0044] In this example, a measurement sample made of a fabric containing the fiber and a reference sample made of a fabric not containing the fiber were prepared, and the normal spectral emissivity of far-infrared rays of these samples was measured. Then, based on the difference between the normal spectral emissivity of far-infrared rays of the measurement sample and that of the reference sample, the intensity of far-infrared rays radiated from the fabric containing the fiber was evaluated. The configuration of each sample and the method for measuring the normal spectral emissivity are as follows.

[0045] Measurement sample The measurement sample is a plain knit fabric made of the above-mentioned fiber, polyester fiber containing no ceramic powder, a blend of polyester fiber and rayon fiber, and polyurethane fiber, and is dyed black using a dye. 2 The mass of the measurement sample per unit area was 180 g, and the mass ratio of the fibers contained in the measurement sample was the above-mentioned fibers: polyester fibers: rayon fibers: polyurethane fibers = 30: 43: 19: 8. The polyester fibers used to prepare the measurement sample had a fineness of 40 denier, the blended yarn had a fineness of 40 count, and the polyurethane fibers had a fineness of 30 denier.

[0046] Reference sample The reference sample is a plain knit fabric made of polyester fiber containing no ceramic powder, a blend of polyester fiber and rayon fiber, and polyurethane fiber, and is dyed black using a dye. 2 The mass of the reference sample per unit area was 180 g, and the mass ratio of the fibers contained in the measurement sample was polyester fiber: rayon fiber: polyurethane fiber = 73: 19: 8. The polyester fiber fineness used to prepare the reference sample was 40 denier, the blended yarn fineness was 40 count, and the polyurethane fiber fineness was 30 denier.

[0047] ·Measuring method for normal spectral emissivity The vertical spectral radiance of far-infrared rays emitted from the measurement sample, reference sample, and blackbody furnace when heated to 40°C was measured using a method in accordance with ISO 19618:2017. The vertical spectral emissivity (unit: %) of the measurement target and reference sample was calculated by expressing the ratio of the vertical spectral radiance of the measurement sample and reference sample as a percentage when the vertical spectral radiance of the blackbody furnace was used as the reference. A Fourier transform infrared spectrophotometer was used to measure the vertical spectral radiance.

[0048] Figure 1 shows the normal spectral emissivity of far-infrared rays emitted from the measurement sample and the reference sample. The vertical axis of Figure 1 represents normal spectral emissivity (unit: %), and the horizontal axis represents measurement wavelength (unit: μm). Figure 2 shows the difference between the normal spectral emissivity of the reference sample and that of the measurement sample. The vertical axis of Figure 2 represents the difference in normal spectral emissivity (unit: %), and the horizontal axis represents measurement wavelength (unit: μm). The difference in normal spectral emissivity can be obtained at each measurement wavelength by subtracting the normal spectral emissivity of the reference sample from the normal spectral emissivity of the measurement sample.

[0049] As shown in Figures 1 and 2, the normal spectral emissivity of the measured sample was higher than that of the reference sample at all measured wavelengths. In particular, the normal spectral emissivity of the measured sample at wavelengths of 6 μm or more and 7 μm or less and at wavelengths of 15 μm or more and 18 μm or less was 5% or more higher than that of the reference sample. From these results, it can be seen that fabrics containing the above-mentioned fibers can emit far-infrared rays with higher intensity than fabrics not containing the above-mentioned fibers.

[0050] Example 2 In this example, the intensity of far-infrared rays was evaluated when the thickness of the fabric containing the above-mentioned fiber was changed. 2The measurement sample and the reference sample have the same configuration as those of Example 1, except that the mass per unit area was changed to 190 g. The method for measuring the normal spectral emissivity of the measurement sample and the reference sample in this example is the same as that in Example 1. Fig. 3 shows the normal spectral emissivity of far-infrared rays emitted from each of the measurement sample and the reference sample. The vertical axis of Fig. 3 represents normal spectral emissivity (unit: %), and the horizontal axis represents measurement wavelength (unit: μm). Fig. 4 shows the difference between the normal spectral emissivity of the reference sample and that of the measurement sample. The vertical axis of Fig. 4 represents the difference in normal spectral emissivity (unit: %), and the horizontal axis represents measurement wavelength (unit: μm).

[0051] As shown in Figures 3 and 4, the normal spectral emissivity of the measured sample was higher than that of the reference sample at all measured wavelengths. In particular, the normal spectral emissivity of the measured sample at wavelengths of 6 μm or more and 7 μm or less and at wavelengths of 13 μm or more and 20 μm or less was 5% or more higher than that of the reference sample.

[0052] (Comparative Example 1) In this example, fibers containing 1.2% or less ceramic powder by mass were produced, and the intensity of far-infrared rays emitted from fabrics containing these fibers was evaluated. The fibers of this example have the same structure as the fibers of Example 1, except that the content of ceramic powder in the fibers is 1.2% by mass.

[0053] In this example, the normal spectral emissivity of far-infrared rays of each sample was measured in the same manner as in Example 1, except that measurement samples and reference samples having the following configurations were used. Then, the intensity of far-infrared rays radiated from the measurement samples was evaluated based on the difference between the normal spectral emissivity of far-infrared rays of the measurement samples and the normal spectral emissivity of the reference samples.

[0054] Measurement sample The measurement sample is a plain knit fabric made of the above-mentioned fiber, polyester fiber containing no ceramic powder, a blend of polyester fiber and rayon fiber, and polyurethane fiber, and is dyed black using a dye. 2The mass of the measurement sample per unit area was 180 g, and the mass ratio of the fibers contained in the measurement sample was the above-mentioned fibers: polyester fibers: rayon fibers: polyurethane fibers = 30: 43: 19: 8. The polyester fibers used to prepare the measurement sample had a fineness of 40 denier, the blended yarn had a fineness of 40 count, and the polyurethane fibers had a fineness of 30 denier.

[0055] Reference sample The reference sample is a plain knit fabric made of polyester fiber containing no ceramic powder, a blend of polyester fiber and rayon fiber, and polyurethane fiber, and is dyed black using a dye. 2 The mass of the reference sample per unit area was 180 g, and the mass ratio of the fibers contained in the measurement sample was polyester fiber: rayon fiber: polyurethane fiber = 73: 19: 8. The polyester fiber fineness used to prepare the reference sample was 40 denier, the blended yarn fineness was 40 count, and the polyurethane fiber fineness was 30 denier.

[0056] Figure 5 shows the normal spectral emissivity of far-infrared rays emitted from the measurement sample and the reference sample. The vertical axis of Figure 5 represents normal spectral emissivity (unit: %), and the horizontal axis represents measurement wavelength (unit: μm). Figure 6 shows the difference between the normal spectral emissivity of the reference sample and that of the measurement sample. The vertical axis of Figure 6 represents the difference in normal spectral emissivity (unit: %), and the horizontal axis represents measurement wavelength (unit: μm).

[0057] As shown in Figures 5 and 6, the normal spectral emissivity of the measurement sample was lower than that of the reference sample at all measurement wavelengths except for wavelengths between 15 μm and 18 μm. Furthermore, there was no measurement wavelength at which the normal spectral emissivity of the measurement sample was 5% or more higher than that of the reference sample.

[0058] From the comparison between the above-mentioned Examples 1 and 2 and Comparative Example 1, it can be seen that by setting the content of the ceramic powder in the fiber within the above-mentioned specific range, it is possible to emit high-intensity far-infrared rays even when the thickness of the fabric is thin.

[0059] Example 3 In this example, a test product containing the fiber of Example 1 and a control product not containing the fiber of Example 1 were prepared, and the blood circulation promoting effect of the fiber was evaluated by comparing the rate of change in blood flow of a wearer when wearing the test product with the rate of change in blood flow of a wearer when wearing the control product. The configuration of the test product, the configuration of the control product, and the method for calculating the rate of change in blood flow are as follows.

[0060] Test item The test items were a long-sleeved inner shirt and leggings made of fabric containing the above-mentioned fiber. The fabric constituting the test items had the same structure as the measurement sample in Example 1.

[0061] Control product The control products were a long-sleeved inner shirt and leggings made of fabric that did not contain the fiber. The fabric that made up the control products had the same structure as the reference sample in Example 1.

[0062] -How to calculate the rate of change in blood flow First, subjects were asked to wear a commercially available long-sleeved inner shirt and leggings that did not emit far-infrared rays. Then, 15 minutes after putting on the commercial items, the blood flow rate (unit: mL / min) of the second finger of the subject's left hand was measured. A laser blood flow meter ("Pocket LDF (registered trademark) MBF-11A" manufactured by JMS Co., Ltd.) was used to measure the blood flow rate.

[0063] Next, the subjects were asked to change from the commercially available product to the test product, and the blood flow rate in the second finger of the left hand was measured 15, 30, 45, and 60 minutes after the change.

[0064] Following the measurement of blood flow when wearing the test product, the same subjects were also measured when wearing the control product. Specifically, the subjects were first asked to change from the test product to the commercial product. Then, 15 minutes after putting on the commercial product, the blood flow (unit: mL / min) of the subject's second finger on the left hand was measured.

[0065] The subjects were then asked to change from the commercial product to the control product. The blood flow rate in the second finger of the subject's left hand was measured 15, 30, 45, and 60 minutes after the change. These blood flow measurements were performed in a test room maintained at a room temperature between 20°C and 25°C, and a relative humidity between 50% and 70% RH, with the subject resting still.

[0066] The blood flow rates at each time point obtained as described above were analyzed as follows, and the rate of change in blood flow when wearing the test product was calculated. First, the blood flow rates 15, 30, 45, and 60 minutes after changing into the test product were plotted on a graph with the vertical axis showing blood flow rate (unit: mL / min) and the horizontal axis showing time elapsed from the time of changing into the test product (unit: min). For convenience, the blood flow rate 15 minutes after wearing the commercial product was plotted on the graph as the blood flow rate at the time of changing into the test product (i.e., 0 minutes after changing into the test product) on the horizontal axis. Next, regression analysis was performed using these data points to determine an approximate line for the five data points. The slope of this line multiplied by 100 was used as the rate of change in blood flow (unit: %) when wearing the test product.

[0067] In addition, instead of the blood flow rate when wearing the test product, the blood flow rate when wearing the control product was used, and the same analysis as above was performed to calculate the rate of change in blood flow rate when wearing the control product (unit: %).

[0068] In this example, the above measurements and analyses were performed on 17 subjects. The composition of the subjects is as follows: Gender breakdown: 8 men, 9 women Average age: 37.5 years (standard deviation 12.0 years) Average height: 166.8cm (standard deviation 9.1cm) Average weight: 57.8kg (standard deviation 10.2kg) Average BMI: 20.6 (standard deviation 1.9)

[0069] Of the 17 subjects, 15 showed a positive rate of change in blood flow when wearing the test product, meaning that their blood flow tended to increase while wearing the test product. The arithmetic mean rate of change in blood flow when wearing the test product was +8.3%, with a standard deviation of 24.3%.

[0070] On the other hand, of the 17 subjects, only 4 had a positive change in blood flow rate when wearing the control product.The arithmetic mean change in blood flow rate when wearing the control product was -15.8%, with a standard deviation of 23.6%.

[0071] Figure 7 shows the arithmetic mean values ​​of the rate of change in blood flow when wearing the test product, the arithmetic mean values ​​of the rate of change in blood flow when wearing the control product, and their standard deviations for 17 subjects. The vertical axis of Figure 7 represents the rate of change in blood flow (unit: %).

[0072] As mentioned above, when wearing the test product, the majority of subjects showed a positive rate of change in blood flow, and the average rate of change in blood flow was also positive. Therefore, although the magnitude of the effect varies from person to person, it can be seen that, on average, wearing the test product increases the wearer's blood flow. In contrast, when wearing the control product, the majority of subjects showed a negative rate of change in blood flow, and the average rate of change in blood flow was also negative. Therefore, it can be seen that, on average, wearing the control product decreases the wearer's blood flow.

[0073] Example 4 In this example, the blood circulation promoting effect of the fibers was evaluated using the same method as in Example 2, except that the shapes of the test product, control product, and commercially available product were changed to short-sleeved inner shirts and boxer shorts, and the composition of the subjects was changed as follows.

[0074] In this example, measurements of blood flow volume and analysis of the rate of change of blood flow volume were performed on 16 subjects. The composition of the subjects is as follows: Gender breakdown: 8 men, 8 women Average age: 40.5 years (standard deviation 8.2 years) Average height: 165.9cm (standard deviation 11.0cm) Average weight: 60.0 kg (standard deviation 9.4 kg) Average BMI: 21.0 (standard deviation 1.5)

[0075] In this example, of the 16 subjects, the percentage change in blood flow when wearing the test product was positive for 4. The arithmetic mean value of the percentage change in blood flow when wearing the test product was -2.8%, with a standard deviation of 25.5%.

[0076] On the other hand, of the 16 subjects, only one had a positive change in blood flow rate when wearing the control product.The arithmetic mean change in blood flow rate when wearing the control product was -18.7%, with a standard deviation of 15.0%.

[0077] Figure 8 shows the arithmetic mean values ​​of the rate of change in blood flow when wearing the test product, the arithmetic mean values ​​of the rate of change in blood flow when wearing the control product, and their standard deviations for 16 subjects. The vertical axis of Figure 8 represents the rate of change in blood flow (unit: %).

[0078] In this example, the average rate of change in blood flow was negative both when the test product and the control product were worn. This is thought to be because the test products in this example were in the form of a short-sleeved inner shirt and boxer shorts, and therefore covered a smaller area of ​​the body surface than the test product in Example 2.

[0079] On the other hand, the average rate of change in blood flow when wearing the test product was greater than the average rate of change in blood flow when wearing the control product. Therefore, although the magnitude of the effect varies from person to person, it can be understood that wearing the test product suppresses the decrease in blood flow in the wearer on average compared to wearing the control product.

[0080] The results of Examples 2 and 3 show that fabrics containing the above-mentioned fibers have the effect of promoting blood flow, and that this effect can increase blood flow and suppress a decrease in blood flow.

[0081] The above describes the embodiments of the fibers, fabrics, and underwear based on Examples 1 to 3, but the specific embodiments of the fibers, fabrics, and underwear according to the present invention are not limited to those of the Examples, and the configurations can be changed as appropriate within the scope that does not detract from the spirit of the present invention.

[0082] For example, the fibers may take the following forms (1) to (7).

[0083] [1] A fiber used in clothing, A thermoplastic resin, and a ceramic powder dispersed in the thermoplastic resin, The ceramic powder contains one or more first ceramic components selected from the group consisting of titania, titanium carbide, and titanium boride; and one or more second ceramic components selected from the group consisting of zirconia, zirconium carbide, and zirconium boride; The mass ratio of the first ceramic component in the ceramic powder is 40 mass% or more and 80 mass% or less, The mass ratio of the second ceramic component in the ceramic powder is 10 mass% or more and less than 25 mass%, The content of the ceramic powder in the fiber is more than 1.2 mass% and not more than 1.8 mass%.

[0084] [2] The fiber described in [1], wherein the ceramic powder contains titania as the first ceramic component. [3] The fiber according to [1] or [2], wherein the ceramic powder contains zirconia as the second ceramic component. [4] The fiber according to any one of [1] to [3], wherein the ceramic powder further contains one or more third ceramic components selected from the group consisting of silica, alumina, alkali metal oxides, alkaline earth metal oxides, and Group 8 metal oxides, and the mass ratio of the third ceramic component in the ceramic powder is greater than 0 mass% and not more than 20 mass%.

[0085] [5] The fiber described in [4], wherein the ceramic powder contains silica and alumina as the third ceramic component. [6] The fiber according to any one of [1] to [5], wherein the fiber has a fineness of 30 denier or more and 150 denier or less. [7] The fiber according to any one of [1] to [6], wherein the thermoplastic resin is polyester.

[0086] The fabric may also take the form shown in [8] or [9] below.

[0087] [8] A fabric comprising the fiber according to any one of [1] to [7], A fabric in which the mass ratio of the fiber in the fabric is 10 mass% or more and 50 mass% or less. [9] 1m 2 The fabric according to [8], having a mass per unit of 100 g or more and 300 g or less.

[0088] The underwear may also take the form shown in

[10] below.

[0089]

[10] Underwear made of the fabric described in [8] or [9].

Claims

1. A fiber used in clothing, A thermoplastic resin, and a ceramic powder dispersed in the thermoplastic resin, The ceramic powder contains one or more first ceramic components selected from the group consisting of titania, titanium carbide, and titanium boride; and one or more second ceramic components selected from the group consisting of zirconia, zirconium carbide, and zirconium boride; a mass ratio of the first ceramic component in the ceramic powder is 40 mass% or more and 80 mass% or less; The mass ratio of the second ceramic component in the ceramic powder is 10 mass% or more and less than 25 mass%, The fiber has a content of the ceramic powder in the fiber of more than 1.2 mass% and not more than 1.8 mass%.

2. The fiber of claim 1 , wherein the ceramic powder comprises titania as the first ceramic component.

3. The fiber of claim 1 , wherein the ceramic powder comprises zirconia as the second ceramic component.

4. The fiber according to claim 1, wherein the ceramic powder further contains one or more third ceramic components selected from the group consisting of silica, alumina, alkali metal oxides, alkaline earth metal oxides, and Group 8 metal oxides, and the mass ratio of the third ceramic component in the ceramic powder is greater than 0 mass% and less than or equal to 20 mass%.

5. The fiber of claim 4 , wherein the ceramic powder comprises silica and alumina as the third ceramic component.

6. The fiber according to claim 1, wherein the fiber has a fineness of 30 denier or more and 150 denier or less.

7. The fiber of claim 1 , wherein the thermoplastic resin is a polyester.

8. A fabric comprising the fiber according to any one of claims 1 to 7, A fabric in which the mass ratio of the fiber in the fabric is 10 mass% or more and 50 mass% or less.

9. 1 m 2 The fabric according to claim 8, having a mass per unit area of ​​100 g or more and 300 g or less.

10. Undergarments made from the fabric of claim 8.

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