Fiber, fabric, wearing article, and manufacturing method of fiber

Abstract

To provide a fiber, a fabric, and a wearing article which can shorten the time required for warming, and a manufacturing method of the fiber.SOLUTION: A fiber F is obtained by kneading a powder P containing iron oxide with a blending ratio within a predetermined range defined in advance, that is, preferably with a blending ratio of, for example, 1 wt.% or more and 20 wt.% or less in the powder P, into a material M of the fiber. The time until warming can be shortened by the fiber F. The particle size of the powder P is preferably 0.1 μm or more and less than 1 μm, and the blending ratio of the powder P in the material M is less than 10% in the weight ratio of the material M.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to fibers, fabrics, garments, and methods for making fibers. [Background technology]

[0002] Among textile products (wearable articles worn on the human body) worn in winter, there are some that use moisture-absorbing heat-generating fibers to increase warmth (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-129947 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional wearable devices, including the technology described in Patent Document 1, take a long time to warm up the body.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a fiber, fabric, wearable item, and method for manufacturing the fiber that can shorten the time it takes to warm up. [Means for solving the problem]

[0006] The fiber of one embodiment of the present invention is The powder containing iron oxide at a blending ratio within a predetermined range is kneaded into a fiber material.

[0007] Further, the fabric of one aspect of the present invention is a fiber obtained by kneading a powder containing iron oxide at a blending ratio within a predetermined range into a fiber material; Another fiber different from the fiber in question, It is composed of.

[0008] In addition, the attachment according to one aspect of the present invention is The above-mentioned fabric is used to wear on the human body.

[0009] A method for producing a fiber according to an embodiment of the present invention corresponds to the above-described fiber according to an embodiment of the present invention. [Effects of the Invention]

[0010] According to the present invention, the time required for heating can be shortened. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the structure of a fiber according to one embodiment of the present invention, based on image analysis of a cross section. [Figure 2] FIG. 2 is a table showing an example of test results when a light absorption heat generation test was conducted on the fiber of FIG. 1 and a fiber as a comparative example. [Figure 3] FIG. 3 is a graph corresponding to the test results of FIG. 2. [Figure 4] FIG. 3 is a thermographic image corresponding to the test results of FIG. 2. [Figure 5] FIG. 2 is a table showing an example of test results when a moisture absorption and heat generation test was conducted on the fiber of FIG. 1 and a fiber as a comparative example. [Figure 6] FIG. 6 is a graph corresponding to the test results of FIG. 5. [Figure 7] FIG. 6 is a diagram for explaining the sample used in the moisture absorption heat generation test of FIG. 5. [Figure 8] 6A and 6B are thermographic images corresponding to the test results of FIG. 5. [Figure 9] FIG. 2 is a diagram showing an example of test results when a thermal effect experiment was conducted on underwear using the fiber of FIG. 1 and underwear using a fiber as a comparative example. [Figure 10]FIG. 2 is a table showing an example of lava suitable for the powder to be kneaded into the fiber of FIG. 1 and the component ratio when the powder made from this lava is kneaded into the fiber. [Figure 11] FIG. 2 is a diagram showing an example of far-infrared radiation characteristics of lava suitable for powder to be kneaded into the fiber of FIG. 1 and a mineral to be used as a comparative example. [Figure 12] FIG. 2 is a table showing an example of test results when a light absorption exothermic test was conducted using a reagent on the iron oxide contained in the fiber of FIG. 1. [Figure 13] FIG. 13 is a graph corresponding to the test results of FIG. 12. [Figure 14] 13A-13C are thermographic images corresponding to the test results of FIG. 12. [Figure 15] 13A-13C are thermographic images corresponding to the test results of FIG. 12. [Figure 16] FIG. 1 is a diagram showing verification of effective blending conditions for iron oxide using a reagent. [Figure 17] FIG. 1 is a table showing an example of test results when a light absorption exothermic test was performed on a compounded reagent (iron oxide, etc.). [Figure 18] FIG. 1 is a table showing an example of test results when a light absorption exothermic test was performed on a compounded reagent (iron oxide, etc.). [Figure 19] 18A and 18B are thermographic images corresponding to the test results of FIG. 17. [Figure 20] 18A and 18B are thermographic images corresponding to the test results of FIG. 17. [Figure 21] 19A-19C are thermographic images corresponding to the test results of FIG. 18. [Figure 22] 19A-19C are thermographic images corresponding to the test results of FIG. 18. [Figure 23] FIG. 1 is a graph showing an example of test results when a light absorption exothermic test was conducted on 16 types of compounded reagents (iron oxide, etc.). DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a diagram showing an example of the structure of a fiber according to one embodiment of the present invention, based on image analysis of a cross section.

[0014] Fiber F in one embodiment of the present invention is obtained by kneading powder P containing iron oxide, described below, at a blending ratio within a predetermined range into material M of fiber F. The following description will be given on the assumption that the powder P is kneaded, but this does not exclude the adhesion of the powder P.

[0015] There are a plurality of fibers F as shown in Fig. 1. Rayon is used as the material M here, but it is not particularly limited. Material M is preferably a material that functions as a moisture-absorbing and heat-generating fiber when made into fiber. Examples include cotton, silk, wool, cupra, hemp, linen, and synthetic fibers, all of which have a high official moisture regain.

[0016] The powder P is kneaded into the material M of the fiber F at a weight ratio of less than 10%. If the amount is more than 10%, the fibers F may break and may not be able to function as fibers. As a lower limit, if the powder P is kneaded into the fiber F material M at a weight ratio of 1% or less, there is a risk that the effect of the fiber F of this embodiment, i.e., the effect of shortening the time it takes to warm up, will not be fully achieved.

[0017] In this embodiment, the powder P has a particle size of less than 1 μm. Specifically, the particle size is 0.1 μm or more and less than 1 μm. By reducing the particle size, a sufficient surface area can be secured within the material M of the fiber F. By securing a sufficient surface area, the power to absorb heat and generate heat can be increased.

[0018] Powder P is obtained from basalt. Preferably, it is obtained from lava of Mount Fuji. In the following, the lava of Mount Fuji will be referred to as "Mount Fuji lava" or "lava" to distinguish it from basalt itself. Powder P may be obtained from basalt or lava from Mt. Fuji, or may be made of the components described below, or a combination of these components with those obtained from basalt or lava from Mt. Fuji, etc.

[0019] The iron oxide blended in the powder P contains at least ferrous oxide. Ferrous oxide is commonly called iron oxide 2 (the 2 is actually a Roman numeral) and is an iron oxide with the formula FeO. When the powder P is obtained from the lava of Mt. Fuji, for example, the iron oxide contained therein is ferric oxide and ferrous oxide having a higher blending ratio than the ferric oxide. Ferric oxide is commonly called iron oxide 3 (the 3 is actually a Roman numeral) and is an iron oxide with the formula Fe2O3.

[0020] As will be described later, when comparing ferrous oxide (FeO) and ferric oxide (Fe2O3), ferrous oxide (FeO) has higher far-infrared heat generation, so in this embodiment, the blending ratio of ferrous oxide (FeO) is higher than that of ferric oxide (Fe2O3). In this embodiment, the blending ratio of ferrous oxide (FeO) is also increased in view of the color appearance of the Mount Fuji lava. The reason for increasing the blending ratio of ferrous oxide (FeO) is that if there is a large amount of ferric oxide (Fe2O3), for example, there are concerns about rust formation, weight increase, and strength decrease.

[0021] The ferrous oxide (FeO) is mixed in the powder P in a weight ratio of 1% to 20% (preferably 5% to 20%, and more preferably 11% to 20%). The blending ratios of 1% to 20% and 5% to 20% will be explained later with reference to FIG. 16 and the like. As will be described later, ferrous oxide (FeO) has the advantage that there is a strong correlation between its blending ratio and temperature, and it can provide a sufficient effect in terms of heat generation. In other words, ferrous oxide (FeO) has the advantage that by adjusting its blending ratio, it is possible to control the temperature according to the purpose and environment of use, for example, in underwear, bedding, rugs, socks, etc.

[0022] The powder P preferably contains silicon dioxide and aluminum oxide in addition to iron oxide. The composition of silicon dioxide and aluminum oxide will also be described later with reference to FIG. The ceramic components such as silicon dioxide and aluminum oxide are blended in an appropriate amount, so that the heat absorbed and generated by the iron oxide can be conducted throughout the entire fiber F. Silicon dioxide can contribute to increasing the moisture absorption and heat generation properties of the fiber F. The blending of silicon dioxide will be described later with reference to FIG. 16 and the like.

[0023] The image on the left in image analysis IA of Figure 1 is an SEM image of fiber F. Powder P is kneaded into material M of fiber F, and its presence can be confirmed in Figure 1. Among the multiple fibers F in the image on the left, the part of the fiber F in the center that appears gray is the material M itself, and the white things scattered among it are particles of powder P (which appear to glow white in the image).

[0024] The image on the right in Image Analysis IA shows the image on the left after image processing and conversion to RGB. In the diagram on the right, points are plotted and connected with lines to grasp the outline of fiber F. The area inside the line (cross-sectional area of ​​fiber F) was calculated, and the amount of multiple particles of powder P contained was measured; in this example, it was about 2% to 4%. From FIG. 1, it can be seen that the powder P is kneaded into the material M of the fiber F at a weight ratio of 10% or less.

[0025] Here, the method for producing the powder P and the fibers F will be described. For the purposes of explanation, the source of the powder P is assumed to be lava from Mt. Fuji, and the material M of the fiber F is assumed to be rayon (although there is no particular limitation as long as it is basalt other than lava from Mt. Fuji, or a material (raw material) that functions as a moisture-absorbing and heat-generating fiber).

[0026] The first step is to prepare the Mount Fuji lava itself. The amount of Mount Fuji lava is optional. In the first step, black Mount Fuji lava is prepared (black Mount Fuji lava contains a lot of ferrous oxide (FeO), while reddish Mount Fuji lava contains a lot of ferric oxide (Fe2O3)). In the first step, this lava is also sorted. The second step involves cutting the prepared Mount Fuji lava into plates of a predetermined size using, for example, a large diamond cutter.

[0027] In the third step, the Mt. Fuji lava cut into plates is cut into pieces the size of a fist, for example, using a large diamond belt cutter. In the fourth step, the fist-sized pieces of Mount Fuji lava are crushed into pieces the size of pebbles, for example. In this step, for example, a drum type crusher is used.

[0028] In the fifth step, the Mount Fuji lava that has been crushed into pebble-sized pieces is ground into fine powder, for example, less than 5 μm in size. In this step, for example, a dry grinder is used. In the sixth step, the Mt. Fuji lava that has been pulverized to a particle size of 5 μm or less is sieved to obtain a fine powder, for example, less than 1 μm, i.e., powder P.

[0029] In the seventh step, the powder P, which has been made into fine particles of less than 1 μm, is kneaded into rayon (material M) to produce fiber F. The fiber F is produced, for example, in the form of cotton (rayon cotton is produced). As for kneading the powder P, for example, the powder P is kneaded in at a ratio of about 10 g per 100 g of rayon cotton. An example of the state in which the powder P is kneaded is shown in FIG.

[0030] In the eighth step, the produced rayon batting is mixed with, for example, cotton batting or acrylic batting and spun into yarn. The cotton and acrylic cotton used in the mix are just examples.

[0031] Next, with reference to Figures 2 to 4, a light absorption heat generation test of the above-mentioned rayon cotton (hereinafter, also referred to as powder-mixed rayon cotton or powder-mixed rayon cotton) will be described. FIG. 2 is a table showing an example of the test results when a light absorption heat generation test was carried out on the fiber of FIG. 1 and a fiber as a comparative example. FIG. 3 is a graphical representation of the test results of FIG. FIG. 4 is a diagram of a thermographic image corresponding to the test results of FIG.

[0032] In Figure 2, the light absorption heat generation test is a test to measure the temperature change when irradiated with light, and the test subjects here are (1) powder-mixed rayon cotton and (2) unprocessed rayon cotton. (1) Powder-mixed rayon cotton shown in Figure 2 is "cotton" made of fiber F with powder P mixed in, and its comparison product is (2) unprocessed rayon cotton, i.e., "cotton" made of ordinary rayon fiber without powder P mixed in.

[0033] The measurement environment was 20°C and 65% RH. In preparation for the light absorption heat generation test, 0.3 g of each of the samples (1) and (2) was loosened under temperature and humidity control in the measurement environment and packed into a plastic petri dish with a diameter of 8.5 cm. As a test method, the sample was placed under a solar light (500W) and irradiated with light under the following conditions. During the light irradiation, the irradiated surface of the sample was photographed using a thermograph. The illumination time is 60 minutes, with the first 30 minutes being the illumination time and the last 30 minutes being the lights off time. The irradiance is approximately 800 W / m 2The type of light source is an artificial solar lamp.

[0034] As shown in Figure 2, Test Item / Result TC1, the initial (before irradiation) sample temperatures (°C) were 21.8°C for (1) powder-mixed rayon cotton and 21.2°C for (2) unprocessed rayon cotton. The temperature (℃) of the samples 5 minutes after the start (5 minutes after the start of irradiation) was 38.8 for (1) powder-mixed processed rayon cotton and 26.6 for (2) unprocessed rayon cotton. The temperature (°C) of the samples 10 minutes after the start (10 minutes after the start of irradiation) was 40.9 for (1) powder-mixed processed rayon cotton and 27.7 for (2) unprocessed rayon cotton. The temperature (°C) of the samples 15 minutes after the start (15 minutes after the start of irradiation) was 41.6 for (1) powder-mixed processed rayon cotton and 28.2 for (2) unprocessed rayon cotton. The temperature (℃) of the samples 20 minutes after the start (20 minutes after the start of irradiation) was 41.4 for (1) powder-mixed processed rayon cotton and 28.2 for (2) unprocessed rayon cotton. The temperature (°C) of the samples 25 minutes after the start (25 minutes after the start of irradiation) was 42.0 for (1) powder-mixed processed rayon cotton and 28.4 for (2) unprocessed rayon cotton. The temperature (°C) of the samples 30 minutes after the start (30 minutes after the start of irradiation) was 41.4°C for (1) powder-mixed processed rayon cotton and 28.4°C for (2) unprocessed rayon cotton.

[0035] The temperature (°C) of the samples 35 minutes after the start (5 minutes after the lights were turned off) was 24.1°C for (1) the powder-mixed rayon cotton and 22.6°C for (2) the unprocessed rayon cotton. The temperature (°C) of the samples 40 minutes after the start (10 minutes after the lights were turned off) was 22.4°C for (1) the powder-mixed rayon cotton and 21.8°C for (2) the unprocessed rayon cotton. The temperature (°C) of the samples 45 minutes after the start (15 minutes after the lights were turned off) was 21.8°C for (1) the powder-mixed rayon cotton and 21.5°C for (2) the unprocessed rayon cotton. The temperature (°C) of the samples 50 minutes after the start (20 minutes after the lights were turned off) was 21.5°C for (1) the powder-mixed rayon cotton and 21.3°C for (2) the unprocessed rayon cotton. The temperature (°C) of the samples 55 minutes after the start (25 minutes after the lights were turned off) was 21.3°C for (1) the powder-mixed rayon cotton and 21.2°C for (2) the unprocessed rayon cotton. The temperature (°C) of the samples 60 minutes after the start (30 minutes after the lights were turned off) was 21.1°C for (1) the powder-mixed rayon cotton and 21.0°C for (2) the unprocessed rayon cotton.

[0036] The maximum heat generation temperature (°C) of (1) powder-mixed rayon cotton was 41.6, and that of (2) unprocessed rayon cotton was 28.4. Therefore, it was found that (1) powder-mixed rayon cotton was 13.2°C higher than (2) unprocessed rayon cotton.

[0037] The above test results are shown in graphs as test result TR1-1 in FIG. 3 and test result TR1-2 in FIG. Figure 3 shows that 5 minutes after the start of irradiation, the temperature rose rapidly to 38.8°C, which is approximately 93% of the maximum heat generation temperature (°C). This shows that the advantage lies in the speed of the radiation reaction after heat absorption. The speed of the radiation reaction is due to the iron oxide contained in the powder P. Figure 4 shows that (1) the powder-mixed rayon cotton maintained a high temperature for 30 minutes after the start of irradiation (30 minutes after irradiation began). In the thermography images taken 30 minutes after the start of irradiation (30 minutes after irradiation began), (1) the powder-processed rayon cotton was 41.4, and (2) the unprocessed rayon cotton was 28.4, which clearly shows that they maintained a high temperature.

[0038] Next, the moisture absorption and heat generation test of powder-mixed rayon and regular rayon will be described with reference to FIGS. FIG. 5 is a table showing an example of test results when a moisture absorption and heat generation test was conducted on the fiber of FIG. 1 and a fiber as a comparative example. FIG. 6 is a graphical representation of the test results of FIG. FIG. 7 is a diagram for explaining the sample used in the moisture absorption heat generation test of FIG. FIG. 8 is a diagram of a thermographic image corresponding to the test results of FIG.

[0039] In Figure 5, the moisture absorption heat generation test involves leaving a test piece in a low humidity environment for at least four hours, then transferring it to a high humidity environment, and measuring the sample surface temperature every minute for 30 minutes using a thermograph. The test piece corresponds to a cushion-shaped sample measuring 10 cm x 10 cm, with each side measuring approximately 10 cm, as shown in sample SP in Figure 7. The measurement surface is the surface of the test piece, specifically a circular area with a diameter of approximately 5 cm in the center of the test piece. The test results are the average of two measurements taken on an area of ​​approximately 5cm. The low humidity environment is a humidity of 20±2°C and 40±5% RH, and the high humidity environment is a humidity of 20±2°C and 90±5% RH. The powder-mixed rayon in the test piece is made of fiber F mixed with powder P, and the regular rayon is made of ordinary rayon fiber.

[0040] As shown in Figure 5, Test Item / Result TC2, and Figure 6, Test Result TR2-1, the test results showed that the measured temperature (°C) at the start (0 minutes) was 20.6 for powder-mixed rayon and 20.5 for regular rayon (see Figure 8, Test Result TR2-2 for thermography images). The measured temperature (°C) after 1 minute was 22.4 for powder-mixed rayon and 22.4 for regular rayon (see test result TR2-2 in Figure 8 for the thermography image after 1 minute). The measured temperature (°C) after 2 minutes was 22.4 for powder-mixed rayon and 22.5 for regular rayon (see test result TR2-2 in Figure 8 for the thermography image after 2 minutes). The measured temperature (°C) after 3 minutes was 22.4 for powder-mixed rayon and 22.4 for regular rayon (see test result TR2-2 in Figure 8 for the thermography image after 3 minutes). The measured temperature (°C) after 4 minutes was 22.4 for powder-mixed rayon and 22.4 for regular rayon. The measured temperature (°C) after 5 minutes was 22.5 for powder-mixed rayon and 22.4 for regular rayon. The measured temperature (°C) after 6 minutes was 22.3 for powder-mixed rayon and 22.3 for regular rayon. The measured temperature (°C) after 7 minutes was 22.4 for powder-mixed rayon and 22.4 for regular rayon. The measured temperature (°C) after 8 minutes was 22.4 for powder-mixed rayon and 22.3 for regular rayon. The measured temperature (°C) after 9 minutes was 22.3 for powder-mixed rayon and 22.2 for regular rayon.

[0041] The measured temperature (°C) after 10 minutes was 22.4 for powder-mixed rayon and 22.3 for regular rayon (see test result TR2-2 in Figure 8 for the thermography image after 10 minutes). The measured temperature (°C) after 11 minutes was 22.2 for powder-mixed rayon and 22.2 for regular rayon. The measured temperature (°C) after 12 minutes was 22.2 for powder-mixed rayon and 22.2 for regular rayon. The measured temperature (°C) after 13 minutes was 22.2 for powder-mixed rayon and 22.1 for regular rayon. The measured temperature (°C) after 14 minutes was 22.1 for powder-mixed rayon and 22.0 for regular rayon. The measured temperature (°C) after 15 minutes was 22.1 for powder-mixed rayon and 22.0 for regular rayon. The measured temperature (°C) after 16 minutes was 22.2 for powder-mixed rayon and 22.1 for regular rayon. The measured temperature (°C) after 17 minutes was 22.1 for powder-mixed rayon and 22.0 for regular rayon. The measured temperature (°C) after 18 minutes was 22.1 for powder-mixed rayon and 22.0 for regular rayon. The measured temperature (°C) after 19 minutes was 22.1 for powder-mixed rayon and 22.0 for regular rayon.

[0042] The measured temperature (°C) after 20 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 21 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 22 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 23 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 24 minutes was 22.1 for powder-mixed rayon and 22.0 for regular rayon. The measured temperature (°C) after 25 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperatures (°C) after 26 minutes were 21.9 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 27 minutes was 21.9 for powder-mixed rayon and 21.8 for regular rayon. The measured temperature (°C) after 28 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 29 minutes was 22.0 for powder-mixed rayon and 21.9 for regular rayon. The measured temperature (°C) after 30 minutes was 21.9 for powder-mixed rayon and 21.8 for regular rayon (see test result TR2-2 in Figure 8 for the thermography image after 30 minutes).

[0043] Figures 5 and 6 show that both the powder-mixed rayon and regular rayon showed a temperature rise of approximately 2°C. It was found that the powder-mixed rayon continued to generate heat approximately 0.1°C higher than regular rayon even after 5 minutes. Therefore, it was found that by kneading powder P into rayon, the heat retention ability of rayon, that is, the ability to retain heat generated by rayon, could be improved by about 5% compared to regular rayon. One factor that contributes to this improved retention is the inclusion of silicon dioxide in powder P. The silicon dioxide increases moisture absorption, which in turn increases the effect of heat of adsorption.

[0044] Next, the thermal effect experiment will be described with reference to FIG. FIG. 9 is a diagram showing an example of test results when a thermal effect experiment was conducted on underwear using the fiber of FIG. 1 and underwear using a fiber as a comparative example.

[0045] In the test result TR3 shown in Figure 9, the powder-mixed rayon blended underwear contains fiber F mixed with powder P, and the unprocessed rayon blended underwear contains the above-mentioned regular rayon (general rayon fiber). Note that for reference, underwear not containing iron oxide, i.e., mineral-mixed underwear without iron oxide, is also included here.

[0046] The powder-mixed rayon blended underwear is manufactured with the above-mentioned powder-mixed rayon 56%, cotton 29%, nylon 10%, and polyurethane 5%. The raw rayon blend underwear is made with 39% polyester, 31% acrylic, 20% regular rayon as mentioned above, and 10% polyurethane. Iron oxide-free mineral-infused underwear is made from a blend of 64% cotton and 36% mineral-infused polyester.

[0047] Test result TR3 in Figure 9 shows the results when these three types of underwear were worn by a 32-year-old female subject, 153 cm tall and weighing 49 kg, in an indoor environment with an ambient temperature of 27°C and humidity of 40%.The skin surface temperature was measured by taking thermographic images of the skin before wearing, 10 minutes after wearing, and 30 minutes after wearing (the thermographic images were taken 10 minutes after wearing).

[0048] The skin surface temperature of the powder-infused rayon blended underwear was 32°C before wearing, 34.0°C after 10 minutes of wearing (a temperature rise of 2°C), and 34.7°C after 30 minutes of wearing (a temperature rise of 2.7°C). In contrast, the skin surface temperature of unprocessed rayon blended underwear was 32.2°C before wearing, 33.8°C after 10 minutes of wearing (a temperature increase of 1.6°C), and 34.3°C after 30 minutes of wearing (a temperature increase of 2.1°C). When wearing the mineral-infused underwear without iron oxide, the skin surface temperature was 32.1°C before wearing, 33.5°C after 10 minutes of wearing (a temperature rise of 1.4°C), and 34.4°C after 30 minutes of wearing (a temperature rise of 2.3°C).

[0049] Figure 9 shows that the powder-infused rayon blended underwear had a higher skin surface temperature 10 minutes and 30 minutes after wearing, demonstrating its superiority over unprocessed rayon blended underwear and mineral-infused underwear without iron oxide. This advantage can be attributed to two effects: the far-infrared heat generating effect of the iron oxide contained in the powder P, and the enhanced moisture absorption heat generating effect of the silicon dioxide also contained in the powder P.

[0050] In the thermal effect experiment, it was found that powder-mixed rayon blended underwear can achieve the two effects mentioned above by generating double heat through far-infrared radiation and moisture absorption (unprocessed rayon blended underwear can only obtain the effect of moisture absorption and heat generation, and iron oxide-free mineral-mixed underwear can only obtain the effect of far-infrared radiation, so it was found that powder-mixed rayon blended underwear has a great advantage).

[0051] Here, lava suitable for processing into powder P and the component ratio when powder P made from this lava is kneaded into fiber F will be described with reference to FIG. FIG. 10 is a table showing an example of lava suitable for the powder to be kneaded into the fiber of FIG. 1 and the component ratio when the powder made from this lava is kneaded into the fiber. It should be noted that the rock is not limited to lava, and may be any basalt with the composition described below.

[0052] The component ratio CR1 shown in Figure 10 indicates that Aokigahara lava from Narusawa Village, Yamanashi Prefecture, is suitable for powder P. The lava contained 51.34% silicon dioxide (SiO2), 17.17% aluminum oxide (Al2O3), and 10.99% iron oxide (FeO) as its main components. Other components included calcium oxide (CaO) 9.81%, magnesium oxide (MgO) 5.27%, sodium oxide (Na2O) 2.71%, titanium oxide (TiO2) 1.44%, potassium oxide (K2O) 0.79%, diphosphorus pentoxide (P2O5) 0.30%, and manganese oxide (MnO) 0.18%.

[0053] The lava in Fiber F consisted of 44.65% silicon dioxide (SiO2), 13.03% aluminum oxide (Al2O3), and 7.40% iron oxide (FeO). It also contained 6.53% calcium oxide (CaO), 4.30% magnesium oxide (MgO), 17.17% sodium oxide (Na2O), 0.00% titanium oxide (TiO2), 6.92% potassium oxide (K2O), 0.00% diphosphorus pentoxide (P2O5), and 0.00% manganese oxide (MnO).

[0054] The component ratio differs from that of the Aokigahara lava because sodium oxide (Na2O) and potassium oxide (K2O) are increased due to the chemicals used in the rayon manufacturing process (corresponding to the seventh process mentioned above), resulting in a relative decrease.

[0055] FIG. 11 is a diagram showing an example of far-infrared radiation characteristics of lava suitable for the powder P to be kneaded into the fiber F of FIG. 1 and a mineral to be used as a comparative example. 11, the horizontal axis of the graph represents wavelength (μm), and the vertical axis represents far-infrared emissivity (1 at the top corresponds to 100%). It is known that the shorter the wavelength of far infrared rays, the greater the thermal energy they emit. Therefore, if the emissivity in the short wavelength range is high, it can be said that heat energy can be absorbed and generated. In the test result TR4 (far-infrared emissivity measurement result) shown in Figure 11, for example, with ceramics C (the mineral used in Figure 9, for example), the far-infrared emissivity decreases in the low wavelength range of 5 μm or less, but Mount Fuji lava L shows a high far-infrared emissivity of 80% to 90% or more even in the low wavelength range of 5 μm or less. Since the far-infrared emissivity is high even in the low wavelength range of 5 μm or less, the heat absorption and heat generation speed are fast (see, for example, FIGS. 2 to 4).

[0056] To explain in more detail, about 70% of the human body is water. This makes it easy to absorb far infrared rays, which reach a depth of about 0.2 mm from the surface of the body and are converted into thermal energy. This converted heat is transmitted throughout the body through the blood flowing through the capillaries, making it feel like your body is warmed from the inside out. Far-infrared rays refer to the wavelength range of 2 μm to 20 μm, but the heat energy is particularly high in the low wavelength range of 3 μm to 5 μm or less. For ordinary minerals, the emissivity drops to about 50% in the 3 μm to 5 μm range, but Figure 11 shows that the far-infrared emissivity of Mount Fuji Lava L is over 80% even in the 3 μm to 5 μm range, with no drop in the emissivity. This is because it contains iron oxide.

[0057] Next, with reference to FIGS. 12 to 15, the test results when a light absorption exothermic test was carried out using a reagent on the iron oxide contained in the fiber F will be described. FIG. 12 is a table showing an example of the test results when a light absorption exothermic test was carried out using a reagent on the iron oxide contained in the fiber of FIG. FIG. 13 is a graphical representation of the test results of FIG. FIG. 14 is a diagram of thermographic images corresponding to the test results of FIG. FIG. 15 is a diagram of thermographic images corresponding to the test results of FIG.

[0058] Here, the purpose of conducting a light absorption heat generation test is to identify the component with the highest far-infrared heat generation property among the main components mentioned above: iron oxide (FeO), silicon dioxide (SiO2), and aluminum oxide (Al2O3). In the light absorption heat generation tests shown in Figures 12 to 15, the samples were four types: (1) ferrous oxide (FeO), (2) ferric oxide (FeO), (3) silicon dioxide (silica), and (4) aluminum oxide α-type. The measurement environment was 20°C and 65% RH. In preparation for the light absorption heat generation test, approximately 15 g of each of the four types of samples described above was flattened and crushed with a spoon in a round petri dish under the measurement environment. As a test method, the sample was placed under a solar light (500W) and irradiated with light under the following conditions. During the light irradiation, the irradiated surface of the sample was photographed using a thermograph. The irradiation time was 60 minutes, with the first 30 minutes being on and the last 30 minutes being off. The irradiance was approximately 800 W / m 2 The type of light source is an artificial solar lamp.

[0059] As shown in Test Item / Result TC3 in Figure 12, the initial (before irradiation) sample temperatures (°C) were: (1) ferrous oxide 21.1, (2) ferric oxide 21.1, (3) silicon dioxide 21.0, and (4) α-aluminum oxide 20.9. The temperatures (°C) of the samples 5 minutes after the start (5 minutes after the start of irradiation) were: (1) ferrous oxide 58.6, (2) ferric oxide 43.0, (3) silicon dioxide 23.8, and (4) α-aluminum oxide 24.4. The temperatures (°C) of the samples 10 minutes after the start (10 minutes after the start of irradiation) were: (1) ferrous oxide 63.5, (2) ferric oxide 46.9, (3) silicon dioxide 24.4, and (4) aluminum oxide α-type 25.2. The temperatures (°C) of the samples 15 minutes after the start (15 minutes after the start of irradiation) were: (1) ferrous oxide 64.7, (2) ferric oxide 48.0, (3) silicon dioxide 24.7, and (4) α-aluminum oxide 25.6. The temperatures (°C) of the samples 20 minutes after the start (20 minutes after the start of irradiation) were: (1) ferrous oxide 65.0, (2) ferric oxide 48.2, (3) silicon dioxide 24.8, and (4) α-aluminum oxide 25.7. The temperatures (°C) of the samples 25 minutes after the start (25 minutes after the start of irradiation) were: (1) ferrous oxide 64.9, (2) ferric oxide 48.5, (3) silicon dioxide 24.8, and (4) α-aluminum oxide 25.7. The temperatures (°C) of the samples 30 minutes after the start (30 minutes after the start of irradiation) were: (1) ferrous oxide 65.8, (2) ferric oxide 48.8, (3) silicon dioxide 25.1, and (4) aluminum oxide α-type 25.7.

[0060] The temperatures (°C) of the samples 35 minutes after the start (5 minutes after the lights were turned off) were: (1) ferrous oxide 30.5, (2) ferric oxide 28.3, (3) silicon dioxide 22.2, and (4) alpha aluminum oxide 22.6. The temperatures (°C) of the samples 40 minutes after the start (10 minutes after the lights were turned off) were: (1) ferrous oxide 23.9, (2) ferric oxide 23.6, (3) silicon dioxide 21.4, and (4) alpha aluminum oxide 21.5. The temperatures (°C) of the samples 45 minutes after the start (15 minutes after the lights were turned off) were: (1) ferrous oxide 22.0, (2) ferric oxide 22.1, (3) silicon dioxide 21.1, and (4) alpha aluminum oxide 21.3. The temperatures (°C) of the samples 50 minutes after the start (20 minutes after the lights were turned off) were: (1) ferrous oxide 21.5, (2) ferric oxide 21.4, (3) silicon dioxide 21.0, and (4) alpha aluminum oxide 21.1. The temperatures (°C) of the samples 55 minutes after the start (25 minutes after the lights were turned off) were: (1) ferrous oxide 21.2, (2) ferric oxide 21.2, (3) silicon dioxide 21.0, and (4) α-aluminum oxide 20.9. The temperatures (°C) of the samples 60 minutes after the start (30 minutes after the lights were turned off) were: (1) ferrous oxide 21.2, (2) ferric oxide 21.0, (3) silicon dioxide 20.9, and (4) alpha aluminum oxide 20.9.

[0061] The calorific value (heat increase (℃)) was 4.1 for (3) silicon dioxide (silicon dioxide) and 4.8 for (4) alpha aluminum oxide, while (1) ferrous oxide was 44.7 and (2) ferric oxide was 27.7. Therefore, it was found that iron oxide has a high heat generation property (far-infrared heat generation property). Furthermore, among iron oxides, (1) ferrous oxide has a higher heat generation property than (2) ferric oxide. Therefore, it was found that the iron oxide contained in the powder P preferably contains only (1) ferrous oxide, or (1) ferrous oxide in a larger amount than (2) ferric oxide.

[0062] The above test results are shown in graphs as test result TR5-1 in FIG. 13, test result TR5-2 in FIG. 14, and test result TR5-3 in FIG. From FIG. 13, it was found that heat was generated suddenly and the temperature rose 5 minutes after the start (5 minutes after the start of irradiation). Figure 14 shows that (1) ferrous oxide and (2) ferric oxide maintained a high temperature 30 minutes after the start of irradiation (30 minutes after the start of irradiation). (Because the samples were placed in round petri dishes, the areas of temperature rise in the thermography image 30 minutes after the start of irradiation (30 minutes after the start of irradiation) appear round.)

[0063] Next, with reference to FIG. 16, effective blending conditions for iron oxide (ferrous oxide (FeO)) using a reagent will be described. FIG. 16 is a diagram showing the verification of effective compounding conditions for iron oxide using a reagent.

[0064] The measurement conditions were as follows: 15 g of each of 14 types of reagents (see (1) to (14) in Figure 16) with different mixing ratios was placed in a petri dish, and then the dish was exposed to a 500 W solar light for 30 minutes, after which the temperature was measured using a thermal camera. Under these conditions, the temperatures of the 14 types of reagents after 30 minutes of irradiation were as shown in the blending ratio temperature result CR2 in FIG.

[0065] That is, in the case of (1) where the compounding ratio was 74.3% silicon dioxide (SiO2), 24.8% aluminum oxide (Al2O3), and 1.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 39.4. (2) When the compounding ratio was 73.5% silicon dioxide (SiO2), 24.5% aluminum oxide (Al2O3), and 2.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 41.5. (3) When the compounding ratio was 72.75% silicon dioxide (SiO2), 24.25% aluminum oxide (Al2O3), and 3.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 44.4. (4) When the compounding ratio was 70.58% silicon dioxide (SiO2), 23.53% aluminum oxide (Al2O3), and 5.90% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 47.6. (5) When the compounding ratio was 69.23% silicon dioxide (SiO2), 23.08% aluminum oxide (Al2O3), and 7.70% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 49.4. (6) When the compounding ratio was 67.50% silicon dioxide (SiO2), 22.50% aluminum oxide (Al2O3), and 10.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 51.8.

[0066] (7) When the compounding ratio was 66.75% silicon dioxide (SiO2), 22.25% aluminum oxide (Al2O3), and 11.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 54.2. (8) When the compounding ratio was 65.63% silicon dioxide (SiO2), 21.88% aluminum oxide (Al2O3), and 12.50% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 53.7. (9) When the compounding ratio was 64.71% silicon dioxide (SiO2), 21.57% aluminum oxide (Al2O3), and 13.72% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 55.1. (10) When the compounding ratio was 62.55% silicon dioxide (SiO2), 20.85% aluminum oxide (Al2O3), and 16.60% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 56.7. (11) When the compounding ratio was 60.00% silicon dioxide (SiO2), 20.00% aluminum oxide (Al2O3), and 20.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 58.3.

[0067] (12) When the compounding ratio was 56.25% silicon dioxide (SiO2), 18.75% aluminum oxide (Al2O3), and 25.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 58.6. (13) When the compounding ratio was 37.5% silicon dioxide (SiO2), 12.5% ​​aluminum oxide (Al2O3), and 50.00% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 59.3. (14) When the compounding ratio was 0.0% silicon dioxide (SiO2), 0.0% aluminum oxide (Al2O3), and 100.0% iron oxide (FeO), the temperature (℃) after 30 minutes of irradiation was 65.8.

[0068] Next, the test results when a light absorption exothermic test was carried out on a compounded reagent (iron oxide, etc.) will be described with reference to FIGS. 17 and 18 are tabular diagrams showing an example of the test results when a light absorption exothermic test was carried out on a compounded reagent (iron oxide, etc.). 19 and 20 are thermographic images corresponding to the test results of FIG. 21 and 22 are thermographic images corresponding to the test results of FIG.

[0069] Here, the purpose of the light absorption exothermicity test is to observe the temperature changes of each of the compounded reagents, Powders A to J and Powders X to Z, which will be described later. 17 to 22, the blending ratio of ferrous oxide (FeO) was varied in the samples Powders A to J and Powders X to Z. The correspondence with FIG. 16 will be described later. The measurement environment was 20°C and 65% RH. In preparation for the light absorption heat generation test, approximately 15 g of each sample was flattened by crushing it with a spoon in a round petri dish under the measurement environment. As a test method, the sample was placed under a solar light (500W) and irradiated with light under the following conditions. During the light irradiation, the irradiated surface of the sample was photographed using a thermograph. The irradiation time was 60 minutes, with the first 30 minutes being on and the last 30 minutes being off. The irradiance was approximately 800 W / m 2 The type of light source is an artificial solar lamp.

[0070] As shown in Test Item / Result TC4-1 in Figure 17, (1) for Powder A, the initial (before irradiation) sample temperature (°C) was 21.2 (see Test Result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 40.7°C. The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 43.9°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 44.2°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 44.2°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 44.6°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 44.4°C (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 26.1°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 22.8°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.3°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.2°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.9 (see test result TR6-1 in Figure 19 for the thermography image).

[0071] (2) For Powder B, the initial (before irradiation) sample temperature (°C) was 21.3. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 43.6°C (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 46.8°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 47.1°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 47.7°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 48.0°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 47.6°C (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 26.6°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.2°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.3°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 22.0. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.9 (see test result TR6-1 in Figure 19 for the thermography image).

[0072] (3) For Powder C, the initial (before irradiation) sample temperature (°C) was 21.3. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 45.8 (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 48.3°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 49.1°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 49.0°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 49.5°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 49.4°C (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 26.8°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.1°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.2°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.0. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.9°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.9 (see test result TR6-1 in Figure 19 for the thermography image).

[0073] (4) For Powder D, the initial (before irradiation) sample temperature (°C) was 21.2. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 47.6°C (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 51.2°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 51.1°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 52.0°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 51.9°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 51.8 (see test result TR6-1 in Figure 19 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 27.3°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.2°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.3°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 22.0. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.9 (see test result TR6-1 in Figure 19 for the thermography image).

[0074] (5) For Powder E, the initial (before irradiation) sample temperature (°C) was 21.3. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 49.3 (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 52.9°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 53.5°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 53.7°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 53.7°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 54.2°C (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 27.6°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.3°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.4°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 22.1°C (see test result TR6-2 in Figure 20 for the thermography image).

[0075] (6) For Powder F, the initial (before irradiation) sample temperature (°C) was 21.3. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 49.4°C (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 52.7°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 53.4°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 53.2°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 52.9°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 53.7°C (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 27.5°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.0. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 21.9°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.8°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.8 (see test result TR6-2 in Figure 20 for the thermography image).

[0076] (7) For Powder G, the initial (before irradiation) sample temperature (°C) was 21.3. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 50.5°C (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 54.1°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 54.3°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 54.8°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 55.1°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 55.1°C (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 27.5°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.1°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.3°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.8°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.8 (see test result TR6-2 in Figure 20 for the thermography image).

[0077] (8) For Powder H, the initial (before irradiation) sample temperature (°C) was 21.3. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 52.2 (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 55.9°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 56.4°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 56.5°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 56.5°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 56.7°C (see test result TR6-2 in Figure 20 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 27.8°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.3°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.4°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.9°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.9 (see test result TR6-2 in Figure 20 for the thermography image).

[0078] As shown in Test Item / Result TC4-2 in Figure 18, for (9) Powder I, the initial (before irradiation) sample temperature (°C) was 21.4 (see Test Result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 53.4°C. The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 57.3°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 57.8°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 58.0. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 58.0°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 58.3 (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 28.4°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.4°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.3°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 22.1°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 22.0. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 22.0 (see test result TR6-3 in Figure 21 for the thermography image).

[0079] (10) For Powder J, the initial (before irradiation) sample temperature (°C) was 21.2 (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 53.5°C. The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 57.4°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 58.4°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 58.4°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 58.6°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 58.6°C (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 28.2°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.3°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.3°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 21.9°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.9°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.9 (see test result TR6-3 in Figure 21 for the thermography image).

[0080] (11) For Powder X, the initial (before irradiation) sample temperature (°C) was 21.5. The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 55.8 (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 59.0°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 59.5°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 59.5°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 59.3°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 59.3 (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 28.1°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 23.3°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 22.2°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 21.8°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.7°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.8 (see test result TR6-3 in Figure 21 for the thermography image).

[0081] (12) For Powder Y, the initial (before irradiation) sample temperature (°C) was 21.6 (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 36.3°C. The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 38.8°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 39.2°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 39.1°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 39.3°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 39.4°C (see test result TR6-3 in Figure 21 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 25.3°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 22.5°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 21.8°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 21.6°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.6°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.5 (see test result TR6-3 in Figure 21 for the thermography image).

[0082] (13) For Powder Z, the initial (before irradiation) sample temperature (°C) was 21.3 (see test result TR6-4 in Figure 22 for the thermography image). The temperature (°C) of the sample 5 minutes after the start (5 minutes after the start of irradiation) was 38.7°C. The temperature (°C) of the sample 10 minutes after the start (10 minutes after the start of irradiation) was 41.1°C. The temperature (°C) of the sample 15 minutes after the start (15 minutes after the start of irradiation) was 41.7°C. The temperature (°C) of the sample 20 minutes after the start (20 minutes after the start of irradiation) was 41.5°C. The temperature (°C) of the sample 25 minutes after the start (25 minutes after the start of irradiation) was 41.4°C. The temperature (°C) of the sample 30 minutes after the start (30 minutes after the start of irradiation) was 41.5 (see test result TR6-4 in Figure 22 for the thermography image). The temperature (°C) of the sample 35 minutes after the start (5 minutes after the lights were turned off) was 25.6°C. The temperature (°C) of the sample 40 minutes after the start (10 minutes after the lights were turned off) was 22.7°C. The temperature (°C) of the sample 45 minutes after the start (15 minutes after the lights were turned off) was 21.9°C. The temperature (°C) of the sample 50 minutes after the start (20 minutes after the lights were turned off) was 21.8°C. The temperature (°C) of the sample 55 minutes after the start (25 minutes after the lights were turned off) was 21.7°C. The temperature (°C) of the sample 60 minutes after the start (30 minutes after the lights were turned off) was 21.7 (see test result TR6-4 in Figure 22 for the thermography image).

[0083] The temperature changes of the above (1) Powder A to (10) Powder J and (11) Powder X to (13) Powder Z correspond to (1) to (14) in FIG. 16, respectively.

[0084] That is, Powder A in FIG. 17(1) corresponds to Powder A in FIG. 16(3) (sample temperature (° C.) 30 minutes after the start of irradiation was 44.4° C.). Powder B in FIG. 17(2) corresponds to Powder B in FIG. 16(4) (sample temperature (°C) 30 minutes after the start of irradiation was 47.6°C). Powder C in FIG. 17(3) corresponds to Powder C in FIG. 16(5) (sample temperature (°C) 30 minutes after the start of irradiation was 49.4). Powder D in FIG. 17(4) corresponds to Powder D in FIG. 16(6) (sample temperature (°C) 30 minutes after the start of irradiation was 51.8). Powder E in FIG. 17 (5) corresponds to Powder E in FIG. 16 (7) (sample temperature (° C.) 30 minutes after the start of irradiation was 54.2° C.). Powder F (6) in FIG. 17 corresponds to (8) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 53.7). Powder G (7) in FIG. 17 corresponds to (9) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 55.1° C.). Powder H (8) in FIG. 17 corresponds to (10) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 56.7).

[0085] Powder I (9) in FIG. 18 corresponds to (11) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 58.3). Powder J (10) in FIG. 18 corresponds to (12) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 58.6). Powder X (11) in FIG. 18 corresponds to (13) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 59.3). Powder Y (12) in FIG. 18 corresponds to (1) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 39.4). Powder Z (13) in FIG. 18 corresponds to (2) in FIG. 16 (sample temperature (° C.) 30 minutes after the start of irradiation was 41.5).

[0086] As can be seen from Figs. 16 to 22, there is a strong correlation between the blending ratio of ferrous oxide (FeO) and temperature, and it was found that a high far-infrared heat generating effect can be obtained even with just 1% blending of ferrous oxide (FeO).

[0087] FIG. 23 is a graph showing an example of the test results when a light absorption exothermic test was conducted on 16 types of compounded reagents (iron oxide, etc.). The light absorption heat generation test was the same as that described above, and therefore the explanation of the test conditions etc. will be omitted here.

[0088] In FIG. 23, (1) is a graph showing the temperature change of a compounded reagent containing 1% iron oxide (ferrous oxide (FeO)). (2) is a graph showing the temperature change of a compounded reagent containing 2% iron oxide (ferrous oxide (FeO)). (3) is a graph showing the temperature change of a compounded reagent containing 3% iron oxide (ferrous oxide (FeO)). (4) is a graph showing the temperature change of a compounded reagent containing 6% iron oxide (ferrous oxide (FeO)). (5) is a graph showing the temperature change of a compounded reagent containing 8% iron oxide (ferrous oxide (FeO)). (6) is a graph showing the temperature change of a compounded reagent containing 10% iron oxide (ferrous oxide (FeO)). (7) is a graph showing the temperature change of a compounded reagent containing 11% iron oxide (ferrous oxide (FeO)). (8) is a graph showing the temperature change of a compounded reagent containing 13% iron oxide (ferrous oxide (FeO)). (9) is a graph showing the temperature change of a compounded reagent containing 14% iron oxide (ferrous oxide (FeO)). (10) shows the temperature change of a compounded reagent containing 17% iron oxide (ferrous oxide (FeO)). (11) shows the temperature change of a compounded reagent containing 20% ​​iron oxide (ferrous oxide (FeO)). (12) shows the temperature change of a compounded reagent containing 25% iron oxide (ferrous oxide (FeO)). (13) shows the temperature change of a compounded reagent containing 50% iron oxide (ferrous oxide (FeO)). (14) shows the temperature change of a compounded reagent containing 100% iron oxide (ferrous oxide (FeO)). (15) shows a graph of the temperature change of a compounded reagent containing 100% silicon dioxide (SiO2) instead of iron oxide (ferrous oxide (FeO)). (16) shows the temperature change of a compounded reagent containing 100% aluminum oxide (Al2O3) instead of iron oxide (ferrous oxide (FeO)).

[0089] As has been explained above with reference to FIGS. 1 to 23, when ferrous oxide (FeO) is compared with ferric oxide (FeO), ferrous oxide (FeO) has higher far-infrared heat generation, and therefore it is preferable to have a higher blending ratio of ferrous oxide (FeO) than ferric oxide (FeO). For example, if there is a large amount of ferric oxide (Fe2O3), there are concerns about rusting, weight increase, and strength decrease, so it is preferable to increase the blending ratio of ferrous oxide (FeO). The ferrous oxide (FeO) is preferably blended in the powder P at a weight ratio of 1% to 20% (more preferably 5% to 20%). If you expect a far-infrared heat generating effect similar to that of the lava from Mount Fuji, it is preferable to mix it at a weight ratio of 11% to 20% of the powder P. The above test results show that the effect can be obtained even if the ratio is more than 20% but less than 50%, but taking into consideration factors such as rust formation and weight increase, the ratio is set at 20% or less here. As described above, there is a strong correlation between the blending ratio of ferrous oxide (FeO) and temperature, and therefore, a sufficient effect can be obtained in terms of heat generation. In other words, by adjusting the blending ratio of ferrous oxide (FeO), it is possible to control the temperature of, for example, underwear, bedding, rugs, shoes, etc., depending on the purpose and environment of use.

[0090] The powder P preferably contains silicon dioxide and aluminum oxide in addition to iron oxide. The ceramic components such as silicon dioxide and aluminum oxide are blended in an appropriate amount, so that the heat absorbed and generated by the iron oxide can be conducted throughout the entire fiber F. Silicon dioxide can contribute to increasing the moisture absorption and heat generation properties of the fiber F. The preferred silicon dioxide blending ratio is 40% to 50% based on the results of Figures 5 to 10. The preferred silicon dioxide blending ratio is 40% to 70% based on the results of Figures 16 to 22. Therefore, the compounding ratio of silicon dioxide is preferably 40% or more, although this will depend on the compounding ratio of iron oxide.

[0091] The fiber F obtained by kneading the powder P containing iron oxide at a blending ratio within a predetermined range into the material M can heat up much faster than conventional fibers. For example, underwear (powder-mixed rayon blend underwear (belly warmer, etc.)) shown in Figure 9, which uses such fiber F, can gain advantages through two effects: the far-infrared heat-generating effect of the iron oxide contained in the powder P, and the enhanced moisture-absorbing heat-generating effect of the silicon dioxide also contained in the powder P.

[0092] Although not specifically shown, the powder-mixed rayon blended underwear (belly warmer) shown in FIG. 9 will be described below. The belly warmer is an ultra-thin one, only 1mm thick. It is able to maintain warmth despite its thickness because it uses fiber F, which is made up of approximately 10g of powder P and 100g of rayon cotton. Fiber F is spun into yarn, and this yarn is then knitted into a gauze-like knit fabric by combining it with, for example, a cotton-blend silk yarn. Two layers of this knitted fabric are layered and knitted together with a stretch yarn to create an uneven air layer. The uneven air layer is formed by the pile knitting on the skin side, and if this air layer is designed to trap the warm air generated by fiber F, a belly warmer that is thin but still provides warmth can be provided. Shorts can be integrated into the underside of such a belly warmer. A belly warmer and shorts combined unit can provide a garment that wraps from the stomach to the base of the thighs. Since veins and lymph nodes are located at the base of the thighs, covering and warming this area can further stimulate blood flow. Examples of wearable items (items worn on the human body) other than the above-mentioned belly warmer and belly warmer / shorts combination include socks, leg warmers, spats, and inner shirts, and these may also be provided.

[0093] In this embodiment, the explanation has been given on the premise that the powder P is kneaded, but the powder P may be made into fibers F attached to the surface of the material M. For example, a manufacturing device may be used that can attach about 10 g of powder P to 100 g of rayon cotton.

[0094] In summary, the fibers, fabrics, attached articles, and fiber manufacturing methods to which the present invention is applied only need to have the following configurations, and various embodiments can be adopted. That is, the fiber to which the present invention is applied (for example, fiber F in FIG. 1) is A powder (such as powder P in FIG. 1) containing iron oxide (such as iron oxides shown in FIGS. 10, 16, 23, etc.) at a blending ratio within a predetermined range (such as a blending ratio of 1% to 20% by weight of powder P) is kneaded into a fiber material (such as material M in FIG. 1 or the material (raw material) of the moisture-absorbing and heat-generating fiber described above). Fiber is enough. Such fibers can help you warm up faster.

[0095] In addition, in the above-mentioned fibers (for example, fiber F in FIG. 1), The predetermined range for the blending ratio of the iron oxide (e.g., iron oxides shown in Figures 10, 16, 23, etc.) is a range in which the weight ratio of the powder (e.g., powder P in Figure 1) is 1% or more and 20% or less. It can be said that:

[0096] In addition, in the above-mentioned fibers (for example, fiber F in FIG. 1), The particle size of the powder (e.g., powder P in FIG. 1) is 0.1 μm or more and less than 1 μm, and the blending ratio of the powder to the material is less than 10% by weight of the material. It can be said that:

[0097] In addition, in the above-mentioned fibers (for example, fiber F in FIG. 1), The iron oxide (e.g., iron oxides shown in Figs. 10, 16, 23, etc.) contains at least ferrous oxide (e.g., ferrous oxide (FeO) shown in Figs. 12 to 15, 23, etc.), It can be said that:

[0098] In addition, in the above-mentioned fibers (for example, fiber F in FIG. 1), The iron oxide (e.g., iron oxides shown in Figs. 10, 16, 23, etc.) contains ferric oxide (e.g., ferric oxide (FeO) shown in Figs. 12 to 15, etc.) and ferrous oxide (e.g., ferrous oxide (FeO) shown in Figs. 12 to 15, 23, etc.) having a higher blending ratio than the ferric oxide, It can be said that:

[0099] In addition, in the above-mentioned fibers (for example, fiber F in FIG. 1), The powder (e.g., powder P in FIG. 1) is obtained from basalt (e.g., basalt including the above-mentioned Mount Fuji lava). It can be said that:

[0100] In addition, in the above-mentioned fibers (for example, fiber F in FIG. 1), The powder (e.g., powder P in FIG. 1) further contains silicon dioxide (e.g., silicon dioxide (SiO2) shown in FIGS. 12 to 15, 23, etc.). It can be said that:

[0101] The fabric to which the present invention is applied (for example, the gauze-like knit fabric used in the manufacture of the above-mentioned belly warmer) is: A powder (such as powder P in FIG. 1) containing iron oxide (such as iron oxides shown in FIGS. 10, 16, 23, etc.) at a blending ratio within a predetermined range (such as a blending ratio of 1% to 20% by weight of powder P) is kneaded into a fiber material (such as material M in FIG. 1 or the material (raw material) of the moisture-absorbing and heat-generating fiber described above), and a fiber (such as fiber F in FIG. 1), Another fiber different from the fiber in question, Any fabric consisting of the above will suffice. Such fabrics can help you warm up faster.

[0102] The present invention is applicable to the wearable product (for example, the above-mentioned belly band, etc.) The above-mentioned fabric (for example, the gauze-like knit fabric used in the manufacture of the above-mentioned belly warmer) is used and worn on a human body (for example, the above-mentioned 32-year-old female subject, height 153 cm, weight 49 kg, etc.), If it is an accessory, it is sufficient. Such an attachment can shorten the time it takes to warm up.

[0103] The method for producing a fiber to which the present invention is applied (for example, fiber F in FIG. 1) is as follows: a step (such as the seventh step described above) of producing a fiber (such as fiber F shown in FIG. 1) by kneading a powder (such as powder P shown in FIG. 1) containing iron oxide (such as iron oxide shown in FIG. 10, FIG. 16, FIG. 23, etc.) at a blending ratio within a predetermined range (such as a blending ratio of 1% to 20% by weight of powder P) into a fiber material (such as material M shown in FIG. 1 or the material (raw material) of the moisture-absorbing and heat-generating fiber described above); It is sufficient that the method for producing the fiber includes the steps of: This manufacturing method can produce a fiber that provides a faster warm-up time. [Explanation of symbols]

[0104] F... Fiber M···Material P...Powder

Claims

1. A fiber obtained by kneading into a fiber material a powder containing ferrous oxide and ferric oxide, the powder containing iron oxides at a blending ratio within a predetermined range, the blending ratio of the ferrous oxide being selected in a manufacturing process so that the blending ratio of the ferrous oxide is higher than the blending ratio of the ferric oxide, the predetermined range for the blending ratio of the iron oxide is a range in which the weight ratio of the ferrous oxide to the powder is 11% or more and 20% or less, When "wadding" made from the fiber into which the powder is kneaded is manufactured, a temperature of 90% or more of the maximum heat generation temperature of the "wadding" after a predetermined irradiation time has elapsed since the start of irradiation in a light absorption heat generation test that measures the temperature change when irradiated with light can be obtained in a short irradiation time close to the start of irradiation. fiber.

2. The powder is obtained from basalt. The fiber of claim 1.

3. The powder further comprises silicon dioxide. The fiber of claim 1.

4. a fiber obtained by kneading into a fiber material a powder containing ferrous oxide and ferric oxide, the powder containing iron oxides at a blending ratio within a predetermined range selected in a manufacturing process so that the blending ratio of the ferrous oxide is higher than the blending ratio of the ferric oxide; Another fiber different from the fiber in question, A fabric consisting of: the predetermined range for the blending ratio of the iron oxide is a range in which the weight ratio of the ferrous oxide to the powder is 11% or more and 20% or less, When "wadding" made from the fiber into which the powder is kneaded is manufactured, a temperature of 90% or more of the maximum heat generation temperature of the "wadding" after a predetermined irradiation time has elapsed since the start of irradiation in a light absorption heat generation test that measures the temperature change when irradiated with light can be obtained in a short irradiation time close to the start of irradiation. material.

5. The fabric according to claim 4 is worn on a human body. Accessories.

6. a step of manufacturing a fiber by kneading a powder containing ferrous oxide and ferric oxide, the powder containing iron oxides at a blending ratio within a predetermined range, the blending ratio of the ferrous oxide being selected so that the blending ratio of the ferric oxide is higher than the blending ratio of the ferric oxide, into a fiber material; A method for producing a fiber comprising: the predetermined range for the blending ratio of the iron oxide is a range in which the weight ratio of the ferrous oxide to the powder is 11% or more and 20% or less, When "wadding" made from the fiber into which the powder is kneaded is manufactured, a temperature of 90% or more of the maximum heat generation temperature of the "wadding" after a predetermined irradiation time has elapsed since the start of irradiation in a light absorption heat generation test that measures the temperature change when irradiated with light can be obtained in a short irradiation time close to the start of irradiation. Fiber manufacturing method.

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