Infrared radiation resin composition

Abstract

The present disclosure provides an infrared radiation resin composition containing an infrared radiation material which has a high emissivity in a prescribed wavelength region and is capable of uniform and stable radiation. An infrared radiation resin composition comprising an infrared radiation material and a resin, the infrared radiation material comprising conductive carbon black and gold nanoparticles, the mass ratio of the conductive carbon black to the gold nanoparticles in the infrared radiation material being 99.95: 0.05 to 99.999: 0.001.

Description

Technical Field

[0001] This invention relates to infrared radiation resin compositions. In particular, this invention relates to infrared radiation resin compositions for use in drying various materials, imparting functional properties such as heat preservation to clothing, cooling and heating, and in beauty and hair care. Background Technology

[0002] Previously, ceramics containing materials such as alumina, titanium dioxide, zirconium oxide, and silicon dioxide were proposed as infrared radiating materials. These materials radiate infrared radiation, which is absorbed by the material, thereby heating it.

[0003] Water molecules undergo vibrational movements such as stretching, contraction, and angular change. When water molecules absorb infrared radiation, they become excited and enter a high-vibrational-state. As a result, the temperature of the water molecules increases. Therefore, when substances containing water molecules, the human body, and plants and animals absorb infrared radiation, their temperature increases.

[0004] Therefore, in order to efficiently heat substances containing water molecules, such as humans, plants, and animals, it is necessary to use infrared radiation materials that emit infrared light of wavelengths that excite the vibrational motion of water molecules. As such infrared radiation materials, the inventors have proposed an infrared radiation material in Patent Document 1 that radiates infrared light that is easily absorbed by humans and other plants and animals.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 2137667 For example, when infrared radiating materials are applied to fibers used in clothing, these materials need to absorb infrared radiation emitted from the human body wearing the clothing to store heat, and then radiate the stored heat energy back to the body in the form of infrared radiation. In other words, the infrared radiating materials are required to absorb infrared radiation emitted from other substances to store heat, and then efficiently radiate the stored heat energy in the form of infrared radiation.

[0006] However, the infrared radiation material described in Patent Document 1 has the following problem: its efficiency in absorbing infrared radiation from the human body and other organisms for heat storage is insufficient. As a result, when radiating the stored heat energy in the form of infrared radiation, the following problem exists: the radiation efficiency is uneven in the wavelength range (e.g., 4–20 μm) that is easily absorbed by the human body and other plants and animals, and the absorption and radiation of infrared radiation from the human body and other plants and animals are insufficient. Summary of the Invention

[0007] The present invention was made in view of the following actual situation, and its object is to provide an infrared radiation resin composition comprising an infrared radiation material having high emissivity and capable of uniform and stable radiation within a specified wavelength region.

[0008] In summary, the solution of the present invention is as follows.

[0009] [1] An infrared radiation resin composition comprising an infrared radiation material and a resin, wherein the infrared radiation material comprises conductive carbon black and gold nanoparticles, and the mass ratio of conductive carbon black to gold nanoparticles in the infrared radiation material is 99.95:0.05 to 99.999:0.001.

[0010] [2] According to the infrared radiation resin composition of [1], the average particle size of the conductive carbon black is 10 nm or more and 100 nm or less.

[0011] [3] The infrared radiation resin composition according to [1] or [2], wherein the gold nanoparticles are particles with irregular shapes.

[0012] [4] The infrared radiation resin composition according to any one of [1] to [3], wherein the gold nanoparticles are nail-shaped gold nanoparticles and the average particle size of the gold nanoparticles is 10 nm or more and 700 nm or less.

[0013] [5] The infrared radiation resin composition according to any one of [1] to [3], wherein the gold nanoparticles are rod-shaped gold nanoparticles, and the average diameter of the gold nanoparticles is 10 nm or more and 50 nm or less, and the average length is 20 nm or more and 250 nm or less.

[0014] [6] The infrared radiation resin composition according to any one of [1] to [5], wherein the infrared radiation resin composition is in the form of a plate, a tube or a sheet, and the infrared radiation material is dispersed in the resin.

[0015] [7] The infrared radiation resin composition according to any one of [1] to [5], wherein the infrared radiation resin composition is fibrous and the infrared radiation material is dispersed in the resin.

[0016] [8] The infrared radiation resin composition according to [6], wherein, relative to 100 parts by mass of the resin, it contains 5 parts by mass and 20 parts by mass of infrared radiation material.

[0017] [9] The infrared radiation resin composition according to [7], wherein, relative to 100 parts by weight of the resin, contains 0.5 parts by weight or more and 2 parts by weight or less of infrared radiation material.

[0018] Invention Effects According to the present invention, an infrared radiation resin composition is provided, which contains an infrared radiation material having high emissivity and capable of uniform and stable radiation within a specified wavelength region. Attached Figure Description

[0019] Figure 1 It is a graph representing the infrared emissivity of a blank sample at wavelengths of 5–20 μm.

[0020] Figure 2 It is a graph showing the infrared emissivity at wavelengths of 5 to 20 μm for the samples of Examples A-1 to A-3.

[0021] Figure 3 It is a graph showing the infrared emissivity of samples B-1 to B-4 at wavelengths of 5 to 20 μm.

[0022] Figure 4 This is a graph showing the body surface temperature of the back of the plain knit T-shirts of Example AMF-1, Comparative Example BMF-1, and Blank L-1 before and 20 minutes after wearing.

[0023] Figure 5 It is a graph showing the temperature change of the nonwoven fabric sheets from the time the nonwoven fabric sheets of Example NWA-1, Comparative Example NWB-1 and Blank BL-1 were heated until 350 seconds later. Detailed Implementation

[0024] The present invention will now be described in detail in the following order based on specific embodiments.

[0025] 1. Infrared radiation resin composition 1.1. Infrared radiation materials 1.2. Conductive Carbon Black 1.3. Gold nanoparticles 2. Method for manufacturing infrared radiation resin composition (1. Infrared radiation resin composition) The infrared radiation resin composition of this embodiment comprises an infrared radiation material and a resin. The infrared radiation material is preferably in powder form, and in the infrared radiation resin composition, the infrared radiation material powder is preferably dispersed in the resin. The infrared radiation material will be described later.

[0026] As the resin, known resins can be used depending on the intended use of the infrared radiation resin composition. Examples of known resins include: thermoplastic resins such as polyester, polyethylene, polypropylene, polystyrene, polycarbonate, polyurethane, acrylic, nylon, polylactic acid resins, and epoxy resins; thermosetting resins such as melamine resins and urea resins; rubbers such as natural rubber and synthetic rubber; and recycled resins such as rayon. In this embodiment, polyolefin-based polypropylene and polyethylene; polyester-based polyethylene terephthalate; and nylon are preferably used.

[0027] The infrared radiation resin composition can be molded into various shapes for use depending on the application. In this embodiment, the infrared radiation resin composition is preferably in the form of a plate, tube, sheet, or fiber, and more preferably in the form of a fiber. In the fibrous infrared radiation resin composition, the infrared radiation material is dispersed in the fibrous resin.

[0028] The fibrous infrared radiation resin composition is a substance produced by a spinning process. Such fibers are chemical fibers artificially manufactured using chemical methods. Chemical fibers include fibers other than natural fibers, such as synthetic fibers (polyester-based, polyamide-based), semi-synthetic fibers (cellulose-based), and regenerated fibers (cellulose-based).

[0029] The mixing ratio of infrared radiating material to resin can be set according to the application. In this embodiment, when the infrared radiating resin composition is in the form of a plate, tube, or sheet, the infrared radiating material is preferably 5 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of resin. Furthermore, when the infrared radiating resin composition is fibrous, the infrared radiating material is preferably 0.5 parts by weight or more and 2.0 parts by weight or less relative to 100 parts by weight of resin.

[0030] (1.1. Infrared radiation materials) Infrared radiating materials are materials that radiate infrared radiation. In this embodiment, materials that radiate infrared radiation with wavelengths suitable for excitation substances, human bodies, plants, animals, etc., containing water molecules are particularly preferred. Furthermore, these infrared radiating materials are preferably materials with high infrared emissivity in the wavelength range of 5 μm to 20 μm, and particularly preferably materials with high infrared emissivity in the wavelength range of 7 μm to 14 μm. Infrared emissivity can be measured using a Fourier Transform Infrared Spectrophotometer (FTIR), for example, based on measurement methods recognized by the Far Infrared Association.

[0031] In this embodiment, the infrared radiating material comprises conductive carbon black and gold nanoparticles. Furthermore, the mass ratio of conductive carbon black to gold nanoparticles in the infrared radiating material is 99.95:0.05 to 99.999:0.001.

[0032] By maintaining the mass ratio of conductive carbon black to gold nanoparticles within the aforementioned range, the absorption and emissivity of infrared radiant heat energy in the infrared radiant material can be improved. Therefore, the infrared emissivity of the infrared radiant material of this embodiment can be increased, and the infrared emissivity can be made uniform within the wavelength range of 5 μm to 20 μm.

[0033] The preferred mass ratio of conductive carbon black to gold nanoparticles is 99.98:0.02 to 99.998:0.002.

[0034] (1.2. Conductive carbon black) Carbon black is an aggregate of largely pure carbon particles. The smallest unit of carbon black is a two-dimensional network (plate) composed of approximately 30-40 six-membered carbon rings bonded together. These network planes are stacked at approximately equal intervals in 3-5 layers, thus forming microcrystals. Then, 1000-2000 microcrystals aggregate to form a primary particle. Further, dozens of primary particles aggregate and chemically and physically combine to form secondary particles. The size of the connections between particles in the secondary particles is called the structure, which affects the physical properties of carbon black.

[0035] The infrared radiation material of this embodiment contains conductive carbon black. The conductivity exhibited by conductive carbon black is manifested through the formation of conductive paths by the movement of π electrons on the carbon six-membered rings on the particle surface. In particular, highly structured carbon blacks with extensive and large secondary structures and network structures in the medium exhibit excellent conductivity.

[0036] There are no particular restrictions on the manufacturing method of conductive carbon black; well-known methods for manufacturing carbon black can be used. Examples of well-known methods include: the oil furnace method, the acetylene method, and the gasification method. For instance, in the oil furnace method, carbon black is generated by the thermal decomposition of hydrocarbons used as raw materials through the heat of combustion of oil or gas. In the acetylene method, carbon black is generated by the thermal decomposition of acetylene. In the gasification method, carbon black is generated using a gasification process of heavy oil.

[0037] In this embodiment, the average particle size of the primary particles of the conductive carbon black is preferably 10 nm or more and 100 nm or less, more preferably 15 nm or more and 70 nm or less. In this embodiment, the average particle size of the primary particles of the carbon black is a value calculated based on the arithmetic mean diameter obtained by observing the primary particles with an electron microscope.

[0038] Commercially available conductive carbon black products include: MITSUBISHI CARBON BLACK "#3230B", MITSUBISHI CARBON BLACK "#3030B", Denka Company's "Denka Black" (powder), and LIONSPECIALTY CHEMICALS' "Ketjenblack EC600JD", etc.

[0039] (1.3. Gold nanoparticles) Gold nanoparticles are aggregates of gold microparticles with a particle size of 1–1000 nm. On the surface of gold nanoparticles, light of a specific wavelength irradiated onto the particles interacts with the electrons on the particle surface, producing a collective vibration phenomenon of electrons known as surface plasmon resonance (SPR).

[0040] The wavelength of the light interacting with the gold nanoparticles varies depending on their shape. This is due to the anisotropic (non-uniform) distribution of the surface electron layers of the gold nanoparticles. For example, spherical gold nanoparticles exhibit maximum absorption of light in the wavelength range of 515–570 nm. On the other hand, gold nanoparticles with irregular shapes other than spherical ones exhibit a redshift in absorption wavelengths compared to spherical gold nanoparticles, resulting in maximum absorption in the infrared region. Consequently, the electromagnetic field generated by surface plasmons is enhanced, leading to stronger light absorption and radiation. As a result, infrared emissivity is increased. Therefore, in this embodiment, irregularly shaped gold nanoparticles are preferred. Furthermore, irregularly shaped gold nanoparticles are preferably unmodified on the surface.

[0041] Examples of gold nanoparticles with irregular shapes include: rod-shaped gold nanoparticles (gold nanorods) and nail-shaped gold nanoparticles (gold nanospikes, gold nanostars).

[0042] Regarding the dimensions of the gold nanorods, the diameter (minor axis diameter) is preferably 10 nm or more and 50 nm or less, more preferably 10 nm or more and 40 nm or less. The length (major axis diameter) is preferably 20 nm or more and 250 nm or less, more preferably 60 nm or more and 180 nm or less. Furthermore, the aspect ratio of the gold nanorods is more preferably 2 or more and 5 or less, more preferably 3 or more and 4 or less. In this embodiment, the diameter and length are values ​​determined by laser diffraction.

[0043] Regarding the size of the gold nanoparticles, the average particle size is preferably 10 nm or more and 700 nm or less, more preferably 15 nm or more and 650 nm or less, and even more preferably 20 nm or more and 600 nm or less. The average particle size is a value determined by laser diffraction.

[0044] Examples of commercially available gold nanoparticles with irregular shapes include: "Gold Nanorods A12-10-2100" and "Gold Nanorods A12-25-1400" manufactured by Nanopartz, and "Gold Nanoparticles GU-100" manufactured by Cytodiagnostics.

[0045] (2. Method for manufacturing infrared radiation resin composition) The infrared radiation resin composition of this embodiment is obtained by mixing a resin with an infrared radiation material in the form of a mixture. Preferably, the infrared radiation material is dispersed in the resin within the mixture. Ideally, the infrared radiation material is uniformly dispersed in the resin at the nanometer to micrometer scale. This dispersion increases the infrared emissivity and reduces energy loss.

[0046] The mixing of resin and infrared radiating material can be carried out, for example, by melt-mixing the resin and infrared radiating material using a known mixing machine. Examples of known mixing machines include mixers, kneaders, rollers, extruders, etc. Alternatively, the mixture of resin and infrared radiating material can be obtained by preparing a masterbatch containing a high concentration of infrared radiating material and then mixing the masterbatch with the remaining resin raw material.

[0047] In this embodiment, the obtained infrared radiation resin composition is preferably molded into a predetermined shape according to the intended use. The molding of the infrared radiation resin composition can be carried out simultaneously with the mixing described above.

[0048] When molding the infrared radiation resin composition into plates, tubes, or sheets, molding methods such as injection molding, extrusion molding, T-die molding, and calendering are preferred. Furthermore, when molding the infrared radiation resin composition into fibers, spinning methods such as melt spinning, dry spinning, wet spinning, and centrifugal spinning are preferred. The fibrous infrared radiation resin composition can then be processed into, for example, fabrics, woven fabrics, nonwoven fabrics, felts, and punching sheets.

[0049] Infrared radiation resin compositions can be used as clothing, medical materials, building materials, and vehicle interior materials, and are particularly preferred for use as clothing and bedding for infrared thermotherapy.

[0050] The embodiments of the present invention have been described above, but the present invention is not limited to any of the above embodiments and can be modified in various ways within the scope of the present invention.

[0051] Example The invention will be described in more detail below using examples, but the invention is not limited to these examples.

[0052] (Experiment 1) As raw materials for infrared radiation materials, conductive carbon black (MITSUBISHI CARBON BLACK "#3230B") and gold nanoparticles (Cytodiagnostics "Gold Nanoparticles GU-100" and Nanopartz "Gold Nanorods A12-10-2100") were prepared. The average particle size of the primary particles of the conductive carbon black was 55 nm, the average particle size D50 of the gold nanoparticles was 100 nm, and the average diameter and average length of the gold nanorods were 110 nm and 175 nm, respectively.

[0053] The prepared conductive carbon black and gold nanoparticles were mixed according to the proportions shown in Table 1 to obtain an infrared radiation material. The conductive carbon black and gold nanoparticles in the obtained infrared radiation material were mixed in a ratio of 1:9 to the mass of polyethylene resin using a mixer (Brabender "Plasti CorderLabstation W50EHT"). The mixture was then mixed for 10 minutes at 50 rpm and 180°C to obtain granules.

[0054] The obtained granules were hot-pressed using a stamping machine (manufactured by Toho Press) at a heating temperature of 200°C and a gauge pressure of 10 MPa to obtain a sheet-like infrared radiation resin composition with dimensions of 100 mm × 100 mm × 0.6 mm.

[0055] It should be noted that, regarding Comparative Example B-4, a sheet-like infrared radiation resin composition was obtained as described above by combining gold nanoparticles and polyethylene resin in a mass ratio of 0.05:99.95. Furthermore, regarding Comparative Example B-5, as a blank, a sheet-like resin composition consisting only of polyethylene resin and containing no infrared radiation material was obtained as described above.

[0056] The infrared spectral emissivity of the obtained infrared radiating resin composition was measured as follows. Test pieces with dimensions of 40 mm × 40 mm were cut from the obtained sheet-like infrared radiating resin composition. Using an infrared spectral emissivity meter (Perkin Elmer "SpectrumOne Frontier T"), under the conditions of a measurement temperature of 40°C, an ambient temperature of 20°C, and a humidity of 65%, the infrared spectral emissivity in the infrared wavelength range (5–20 μm) was measured by FT-IR. Furthermore, the infrared spectral emissivity of a blank sample was also measured under the above conditions. The average emissivity of the blank sample in the infrared wavelength range (7–14 μm) calculated from the measurement results was 86.1%.

[0057] In this embodiment, considering the evaluation criteria of "radiation characteristics and spectral emissivity" in the "Evaluation Criteria for Infrared Fiber Products" stipulated by the Far Infrared Association, samples with an average emissivity of 94.7% or higher within the infrared wavelength range (7–14 μm) are judged to be good. The results are shown in Table 2 and... Figures 1-3 . According to Table 2 and Figures 1-3 It can be confirmed that when the infrared radiation material contains the above-mentioned components and their content is within the above-mentioned range, an infrared radiation resin composition with high and uniform average emissivity can be obtained.

[0058] (Experiment 2) As raw materials for infrared radiation materials, conductive carbon black (MITSUBISHI CARBON BLACK "#3030B") and gold nanoparticles (Nanopartz "Gold Nanorods A12-25-1400") were prepared. The conductive carbon black had an average particle size D50 of 55 nm, and the gold nanorods had an average diameter of 25 nm and an average length of 245 nm.

[0059] Infrared radiating material was obtained by mixing the prepared conductive carbon black with gold nanoparticles at a mass ratio of 99.99:0.01. The infrared radiating material was then mixed with nylon resin at a mass ratio of 1:9 using a resin melting and mixing apparatus (Toyo Seiki Co., Ltd. "50C type 150") at a heating temperature of 270°C and a rotation speed of 100 rpm to produce masterbatch A3M-1.

[0060] Next, the obtained masterbatch A3M-1 was combined with nylon resin at a mass ratio of 1:9, and nylon multifilament yarn AMF-1 with a fineness of 88 dtex and a single filament number of 36f was produced by melt spinning using a multifilament manufacturing device (made by Musashino Kikai) at a heating temperature of 280°C.

[0061] The nylon multifilament AMF-1 produced is processed using the POY / DTY method (a method in which POY (partially oriented yarn) is produced by high-speed spinning and partial stretching, and then the POY is stretched / false-twisted to produce DTY (drawn textured yarn)). POY yarn is produced under the condition that the false-twisted POY stretching roller winding speed is 4000m / min. DTY yarn is then twisted at 3200t / m, heated, and the twist is restored to produce a large-volume and elastic yarn.

[0062] The processed AMF-1 is used to make fabric using a circular knitting machine / plain knitting machine (Fukuhara Seiki Manufacturing Co., Ltd. MXC-S3.2) to produce plain knit T-shirts (AMF-1).

[0063] Infrared radiation material is prepared by using a mass ratio of conductive carbon black to gold nanoparticles of 99.92:0.08. In addition, nylon multifilament yarn BMF-1 is prepared by the same method as described above. Plain knit T-shirt (BMF-1) is then made using the prepared nylon multifilament yarn BMF-1.

[0064] Furthermore, using a resin composition consisting only of nylon resin and free of infrared radiation materials, nylon multifilament yarn L-1 is produced by the same method as described above, and plain knit T-shirt (L-1) is produced using the produced nylon multifilament yarn L-1.

[0065] The test subjects wore the prepared plain knit T-shirts according to the test method shown below, and their body surface temperature was measured after removing the shirts to evaluate the heat retention properties of the plain knit T-shirts.

[0066] After entering the laboratory, where the room temperature was maintained at 20°C and the humidity at 65%, the subject remained seated and quiet. A thermal imager (FLIR A615, FLIR Systems Inc.) was used to measure the surface temperature of the test site (back). The surface temperature at the stabilized time point was set as the surface temperature before wearing the garment. After confirmation, the subject put on the prepared plain-knit T-shirt and remained seated and quiet for 20 minutes. The plain-knit T-shirt was then removed. The surface temperature of the back was measured immediately after removing the garment using the thermal imager (FLIR A615, FLIR Systems Inc.). The results are shown in Table 3 and... Figure 4 . According to Table 3 and Figure 4 It can be confirmed that the plain knit T-shirt (AMF-1) has high heat retention.

[0067] (Experiment 3) As raw materials for infrared radiation materials, conductive carbon black (MITSUBISHI CARBON BLACK "#3230B") and gold nanoparticles (Cytodiagnostics "Gold Nanoparticles GU-100") were prepared. The average particle size D50 of the conductive carbon black was 23 nm, and the average particle size D50 of the gold nanoparticles was 100 nm.

[0068] Infrared radiating material (same formulation as in Example A-3) was obtained by mixing the prepared conductive carbon black with gold nanoparticles at a mass ratio of 99.995:0.005. Masterbatch AN-1 was then produced by mixing the infrared radiating material with polyethylene terephthalate (PET) resin at a mass ratio of 1:9 using a resin melting and mixing apparatus (Toyo Seiki Co., Ltd. "50C type 150") at a heating temperature of 280°C and a rotation speed of 100 rpm.

[0069] Next, the obtained masterbatch AN-1 and PET resin were combined at a mass ratio of 1:9, and a PET resin artificial short fiber yarn STA-1 with a fineness of 6.6 dtex and a fiber length of 51 mm was produced by melt spinning using a short fiber spinning and stretching manufacturing device at a heating temperature of 280°C.

[0070] Using the manufactured synthetic short fiber yarn STA-1 as raw material, a carding machine (Ikegami Machinery Co., Ltd. "H2DS") is used to form a web. The web is then layered multiple times using a laminating machine (Ikegami Machinery Co., Ltd. "IK30-2"), and finally produced using a nonwoven fabric needle punching machine (FEILER Co., Ltd. "NL21") to create a fabric with a width of 1000mm and a thickness of 100g / m².2 PET nonwoven fabric NWA-1.

[0071] Infrared radiation material was obtained by combining conductive carbon black and gold nanoparticles in a mass ratio of 99.5:0.5. In addition, PET resin artificial short fiber yarn STB-1 was made by the same method as above, and PET nonwoven fabric NWB-1 was made using the artificial short fiber yarn STB-1.

[0072] Furthermore, a resin composition consisting only of PET resin without infrared radiation materials is used. In addition, PET resin artificial short fiber yarn BL-1 is produced by the same method as described above. PET nonwoven fabric BL-1 is produced using the artificial short fiber yarn BL-1.

[0073] The temperature change of the produced PET nonwoven fabric was measured as described below.

[0074] Test pieces measuring 200mm × 150mm were cut from the obtained PET nonwoven fabric. Two halogen lamps (CASTER CHP-500) were positioned opposite each other, one above the other, to heat the cut test pieces at an angle. The average temperature of the test pieces (PET nonwoven fabric) was measured from the start of heating for 180 seconds. The halogen lamps had an output of 500W. The average temperature of the test pieces was measured from above using an infrared camera (FLIR Systems Inc. FLIRSC655) detecting the spectrum from 7.5 to 14 μm. The results are shown in Table 4 and... Figure 5 . According to Table 4 and Figure 5 It can be confirmed that the heat energy radiated from PET nonwoven fabric NWA-1 is high.

[0075] (Experiment 4) Four subjects, two men and two women, alternately wore the plain knit T-shirt (AMF-1) and the plain knit T-shirt (blank L-1) obtained in Experiment 3. Blood flow data were measured using the following method for the subjects wearing the plain knit T-shirt (AMF-1) and the subjects wearing the plain knit T-shirt (blank L-1).

[0076] As a blood flowmeter, a blood flowmeter (OMEGAWAVE Co., Ltd., OMEGAFLO-Lab laser blood flowmeter) with a contact probe capable of continuously measuring subcutaneous microcirculation was used to measure tissue blood flow (mL / min / 100g) at a depth of approximately 1 mm from the subcutaneous surface. Regarding the measurement site, the skin surface of the abdomen covered by a plain-knitted T-shirt was designated as the measurement site. The probe was fixed to the measurement site, and blood flow was measured every second for 30 minutes (1800 seconds) at room temperature of 25°C and humidity of 50%. The measurement results were analyzed using t-tests. Based on the results, when the p-value (T≤t) was less than the significance level (0.05), the blood flow when wearing AMF-1 was statistically significantly increased compared to that when wearing L-1. The results are shown in Table 5.

[0077] Furthermore, the rate of change of mean blood flow when wearing a plain knit T-shirt (AMF-1) versus when wearing a plain knit T-shirt (blank L-1) was calculated as follows. First, the difference between the mean blood flow when wearing a plain knit T-shirt (AMF-1) and the mean blood flow when wearing a plain knit T-shirt (blank L-1) (“mean blood flow when wearing a plain knit T-shirt (AMF-1)” - “mean blood flow when wearing a plain knit T-shirt (blank L-1)”) was calculated using the formula “(difference in mean blood flow / mean blood flow when wearing a plain knit T-shirt (blank L-1)) × 100”. The results are shown in Table 5. According to Table 5, based on the results of the t-test comparing the average blood flow when wearing the plain knit T-shirt (AMF-1) and the average blood flow when wearing the plain knit T-shirt (blank L-1), it can be confirmed that the blood flow increased statistically significantly when wearing the plain knit T-shirt (AMF-1) compared to when wearing the plain knit T-shirt (blank L-1). Furthermore, it can be confirmed that, according to the blood flow improvement regulations for far-infrared clothing for promoting blood circulation in the home (Class 1 medical devices) established by the Ministry of Health, Labour and Welfare, the rate of change in the average blood flow of the subjects was 5% or more.

[0078] Industrial availability The infrared radiation resin composition of the present invention contains an infrared radiation material with a high average emissivity within a specified wavelength region, and is therefore suitable as a fiber for clothing requiring heat insulation, or as a material for drying various materials.

Claims

1. An infrared radiation resin composition comprising an infrared radiation material and a resin, The infrared radiation material comprises conductive carbon black and gold nanoparticles. In the infrared radiation material, the mass ratio of the conductive carbon black to the gold nanoparticles is 99.95:0.05 to 99.999:0.

001.

2. The infrared radiation resin composition according to claim 1, wherein, The conductive carbon black has an average particle size of 10 nm or more and 100 nm or less.

3. The infrared radiation resin composition according to claim 1, wherein, The gold nanoparticles are particles with irregular shapes.

4. The infrared radiation resin composition according to claim 3, wherein, The gold nanoparticles are nail-shaped gold nanoparticles with an average particle size of 10 nm or more and 700 nm or less.

5. The infrared radiation resin composition according to claim 3, wherein, The gold nanoparticles are rod-shaped gold nanoparticles with an average diameter of 10 nm or more and 50 nm or less, and an average length of 20 nm or more and 250 nm or less.

6. The infrared radiation resin composition according to any one of claims 1 to 5, wherein, The infrared radiation resin composition is in the form of plates, tubes, or sheets, and the infrared radiation material is dispersed in the resin.

7. The infrared radiation resin composition according to any one of claims 1 to 5, wherein, The infrared radiation resin composition is fibrous, and the infrared radiation material is dispersed in the resin.

8. The infrared radiation resin composition according to claim 6, wherein, The infrared radiating material comprises 5 parts by mass and 20 parts by mass relative to 100 parts by mass of the resin.

9. The infrared radiation resin composition according to claim 7, wherein, The infrared radiating material comprises 0.5 parts by weight and less than 2 parts by weight relative to 100 parts by weight of the resin.

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