Post-treatment method for promoting biodegradation

Abstract

The post-treatment method for promoting the biodegradation of a fabric according to the present invention can further promote the biodegradation of the fabric by fixing it to the fabric after treatment with a biodegradation-promoting substance, and can prevent the reduction of biodegradation of the fabric through post-treatment such as removing the lubricant applied during the knitting and weaving of the fabric, removing surface residues during the dyeing of the fabric, or adjusting processing conditions during the tendering process, and is expected to be utilized in the biodegradable fabric industry.

Description

Technology Field

[0001] The present invention relates to a post-treatment method for promoting the biodegradation of yarns and fabrics, and more specifically, to a method such as immobilizing an accelerator to promote biodegradation so that polymers constituting yarns and fabrics decompose at a faster rate in the field of eco-friendly clothing manufacturing. Background Technology

[0003] In general, yarns or fabrics primarily used in daily life utilize a variety of materials, including cotton, silk, wool, leather, and polyester. Polyester, in particular, is a widely used synthetic polymer characterized by high durability and excellent physical properties. It is primarily used in the textile industry for the manufacture of clothing, bags, and various woven or knitted products. However, polyester poses environmental problems due to its difficulty in biodegradation. Traditional polyester does not decompose for decades, exacerbating the issue of plastic pollution.

[0004] Existing biodegradation technologies for synthetic fibers secured biodegradability through methods such as compounding materials that are relatively easy to biodegrade during polymerization at the yarn manufacturing stage. However, existing technologies had problems where physical properties such as strength were very low in inverse proportion to biodegradability, making product manufacturing impossible, or where biodegradability significantly decreased during the processing steps used to manufacture products.

[0005] Therefore, there is a growing need for technology that enhances biodegradability through additional processing after fabric manufacturing and maintains biodegradability for an extended period. Prior art literature

[0007] Japanese Patent Publication No. 2023-111213 The problem to be solved

[0008] The present invention relates to a post-treatment method for promoting the biodegradation of a fabric to improve the biodegradability of the fabric as described above and to maintain biodegradability for a long period of time.

[0009] The present invention will be described in detail below.

[0010] First, devices and equipment used in processing and manufacturing the fabric according to the embodiments of the present invention may be used, such as devices and equipment used in the same technical field.

[0012] The present invention comprises the step of (a) manufacturing a fabric using a polymer fabric or knitted fabric;

[0013] (b) a step of treating the fabric manufactured above with a biodegradation promoting substance; and

[0014] (c) a step of fixing the above-mentioned treated fabric by heat treating it at 80°C to 300°C for 10 seconds to 1 hour; the present invention provides a post-treatment method for promoting the biodegradation of a fabric, comprising: (c) a step of fixing the above-mentioned treated fabric by heat treating it at 80°C to 300°C for 10 seconds to 1 hour.

[0015] In this specification, "Woven Fabric" refers to a fabric made by interlacing two or more threads, and may include woven fabrics, knitted fabrics, circular knitted fabrics, and flat knitted fabrics.

[0016] In this specification, "knitted fabric" refers to a fabric made by weaving yarn into a loop shape, and may include warp knits, circular knits, and flat knits.

[0017] In one embodiment of the present invention, step (b) may involve treating the fabric by spraying a biodegradation-promoting composition comprising tungsten oxide-based nanomaterials, an organic acid, and a binder.

[0018] In one embodiment of the present invention, the tungsten oxide-based nanomaterial is CTO (Cesium-Tungsten-Oxide), ITO (Indium-Tin-Oxide), ATO (Antimony-Tungsten-Oxide), WO3 (Tungsten Trioxide), copper tungsten oxide (CuWO4), tungsten-arsenic oxide (As₂WO4), tungsten-iron oxide (Fe₂WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4).4) It may be one or more tungsten oxide-based materials selected from the group consisting of, but is not limited thereto.

[0019] In one embodiment of the present invention, the average particle size of the tungsten oxide-based nanomaterial may be 30 nm to 70 nm.

[0020] In the present invention, the tungsten oxide-based nanomaterial exhibits the type and particle size described above, thereby absorbing (shielding) light energy in specific wavelength ranges such as infrared rays, and has a high heat capacity, allowing for the securing of more thermal energy from the fiber surface, which can promote the occurrence of hydrolysis.

[0021] In this specification, "organic acid" means a compound containing -OH groups and -COOH groups.

[0022] In one embodiment of the present invention, the organic acid may be one or more selected from the group consisting of glutaric acid, succinic acid, acetic acid, citric acid, formic acid, phthalic acid, malic acid, tartaric acid, oxalic acid, benzoic acid, and fumaric acid.

[0023] In one embodiment, the organic acid may be glutaric acid or succinic acid, and may serve as a dispersion aid to help stabilize dispersion when dispersing the tungsten oxide-based nanomaterial under processing liquid conditions.

[0024] In the present invention, the organic acid acts to increase hydrophilicity on the fiber surface, thereby enhancing the very low wettability and ability to contact moisture of the fabric, and thus can improve contact with moisture for hydrolysis to occur.

[0025] In one embodiment of the present invention, as the tungsten oxide-based nanomaterial absorbs light in the wavelength range of 300 nm to 600 nm or light in the wavelength range of 700 nm to 2500 nm and increases the surface temperature, an organic acid can further enhance the hydrophilicity of the fiber surface to exhibit a synergistic effect.

[0026] In one embodiment of the present invention, a tungsten oxide-based nanomaterial can absorb light in the wavelength range of 300 nm to 600 nm and increase the surface temperature.

[0027] In one embodiment of the present invention, a tungsten oxide-based nanomaterial can absorb light in the wavelength range of 700 nm to 2500 nm, 750 nm to 2500 nm, 700 nm to 2450 nm, or 750 nm to 2450 nm and increase the surface temperature.

[0028] In this specification, "binder" refers to a substance that plays a role in helping the tungsten oxide-based nanomaterial and organic acid, etc., to be stably fixed to the surface of the fiber.

[0029] In one embodiment of the present invention, the binder may be one or more selected from the group consisting of acrylic, polyethylene, polyurethane, and polyvinylpyrrolidone.

[0030] In the present invention, the binder can enhance the biodegradability of the fabric by causing a biodegradation promoting substance to adhere to the fabric surface along with it during the process of melting and adhering when thermal energy is applied.

[0031] In one embodiment of the present invention, the biodegradation-promoting composition may further include one or more components selected from the group consisting of dispersants, dispersion aids, thickeners, and defoaming agents.

[0032] As the weaker or insufficient the surface adhesion, the more the biodegradation-promoting substance is continuously shed during the consumer use phase, which may lead to a decline in the biodegradation-promoting effect of the fabric during the landfill phase; therefore, a technology for adhering the biodegradation-promoting agent to the fabric surface allows the substances contained in the agent to remain stably on the fiber surface, thereby maintaining the biodegradation-promoting effect.

[0033] By controlling the temperature range during the tenter process, the degree of crystallization of the fabric surface can be controlled. If the temperature falls outside this range, phenomena such as increased crystallization or increased smoothness of the fabric surface may occur, which may have a negative effect on biodegradability.

[0034] In one embodiment of the present invention, step (c) is 80°C to 300°C, 80°C to 290°C, 80°C to 280°C, 80°C to 270°C, 80°C to 260°C, 80°C to 250°C, 90°C to 300°C, 90°C to 290°C, 90°C to 280°C, 90°C to 270°C, 90°C to 260°C, 90°C to 250°C, 100°C to 300°C, 100°C to 290°C, 100°C to 280°C, 100°C to 270°C, 100°C to 260°C, 100°C to 250°C, 120°C to 300°C, 120°C to 290°C, 120°C to The step may be to fix by heat treatment at 280℃, 120℃ to 270℃, 120℃ to 260℃, 120℃ to 250℃, 150℃ to 300℃, 150℃ to 290℃, 150℃ to 280℃, 150℃ to 270℃, 150℃ to 260℃, or 150℃ to 250℃.

[0035] In one embodiment of the present invention, step (c) is 10 seconds to 1 hour (i.e., 3,600 seconds), 10 seconds to 50 minutes (i.e., 3,000 seconds), 10 seconds to 40 minutes (i.e., 2,400 seconds), 10 seconds to 30 minutes (i.e., 1,800 seconds), 10 seconds to 20 minutes (i.e., 1,200 seconds), 20 seconds to 1 hour (i.e., 3,600 seconds), 20 seconds to 50 minutes (i.e., 3,000 seconds), 20 seconds to 40 minutes (i.e., 2,400 seconds), 20 seconds to 30 minutes (i.e., 1,800 seconds), 20 seconds to 20 minutes (i.e., 1,200 seconds), 30 seconds to 1 hour (i.e., 3,600 seconds), 30 seconds to 50 minutes (i.e., 3,000 seconds), It may be a step of fixing by heat treatment for 30 to 40 minutes (i.e., 2,400 seconds), 30 to 30 minutes (i.e., 1,800 seconds), or 30 to 20 minutes (i.e., 1,200 seconds).

[0037] In one embodiment of the present invention, step (a) may be to manufacture a fabric by knitting a polymer fabric or knitted yarn coated with an emulsion.

[0038] In this specification, "emulsion" refers to an oil or chemical substance used in the production process of woven or knitted fabrics, which may be used to reduce friction between fibers and facilitate the smooth operation of machinery. In the knitting process, the emulsion helps the warp and weft threads cross smoothly and can provide a lubricating function that reduces friction and prevents wear on the machinery. Additionally, the emulsion can coat the surface of the fibers to prevent damage that may occur during the weaving process.

[0039] In one embodiment of the present invention, the emulsion may be applied to the yarn or fabric by a spray method or an immersion method.

[0040] In one embodiment of the present invention, a post-treatment method for promoting the biodegradation of a fabric may further include (d) a step of removing the emulsion applied in step (a).

[0041] In one embodiment, the above step (d) may be i) removing the emulsion by washing with a neutral detergent at 30°C to 50°C for 2 to 4 hours.

[0042] In one embodiment, the above step (d) may be ii) removing the oil by treating the fabric with a cleaning agent having a pH of 5 to 8 for 2 to 4 hours.

[0043] In one embodiment, the above step (d) may be iii) washing the fabric with hot water at 70°C to 120°C to remove the oil.

[0044] In one embodiment, the above step (d) may be iv) removing the lubricant by treating the fabric with steam at 100°C to 120°C.

[0045] In one embodiment, the above step (d) may be v) removing the emulsion by treating the fabric with ultrasound at 20 kHz to 100 kHz.

[0047] In one embodiment of the present invention, a post-treatment method for promoting the biodegradation of a fabric may further include a dyeing step of applying color to the fabric by treating it with a dye at 130°C to 150°C for 1 to 2 hours.

[0048] In one embodiment of the present invention, the dye used in the dyeing step (e) may be an acid dye or a dispersing dye. Acid dyes have good bonding strength with polyester and can be used at high temperatures. Dispersing dyes have high affinity with polyester and can be effectively dyed at high temperatures.

[0049] In one embodiment, the dye may be an acidic dye with a pH of 1 to 3.

[0050] In one embodiment of the present invention, the pH adjuster may be an acidic adjuster or a basic (alkaline) adjuster. In one embodiment, the alkaline adjuster may be sodium hydroxide.

[0051] In one embodiment of the present invention, a post-treatment method for promoting the biodegradation of a fabric may further include the step of (f) treating with an alkaline adjusting agent to adjust the pH to 4.5 to 5.5 and rinsing the fabric 3 to 5 times with running water to remove surface residues.

[0053] In addition, the present invention comprises the step of treating a polymer product with a biodegradation-promoting substance; and

[0054] A post-treatment method for promoting the biodegradation of a polymer product is provided, comprising the step of fixing the above-mentioned treated polymer product by heat-treating it at 80°C to 300°C for 10 seconds to 1 hour.

[0055] In this specification, the polymer product may be a product made of polymer materials such as PET, PLA, etc., having hydrolysis as a biodegradable basis, such as a film, bottle, or plate.

[0056] In one embodiment of the present invention, the step of heat-treating and fixing the polymer product is 80°C to 300°C, 80°C to 290°C, 80°C to 280°C, 80°C to 270°C, 80°C to 260°C, 80°C to 250°C, 90°C to 300°C, 90°C to 290°C, 90°C to 280°C, 90°C to 270°C, 90°C to 260°C, 90°C to 250°C, 100°C to 300°C, 100°C to 290°C, 100°C to 280°C, 100°C to 270°C, 100°C to 260°C, 100°C to 250°C, 120°C to 300°C, 120°C to 290°C, The step may be to heat treat at 120℃ to 280℃, 120℃ to 270℃, 120℃ to 260℃, 120℃ to 250℃, 150℃ to 300℃, 150℃ to 290℃, 150℃ to 280℃, 150℃ to 270℃, 150℃ to 260℃, or 150℃ to 250℃.

[0057] In one embodiment of the present invention, the step of heat-treating and fixing the polymer product is performed for 10 seconds to 1 hour (i.e., 3,600 seconds), 10 seconds to 50 minutes (i.e., 3,000 seconds), 10 seconds to 40 minutes (i.e., 2,400 seconds), 10 seconds to 30 minutes (i.e., 1,800 seconds), 10 seconds to 20 minutes (i.e., 1,200 seconds), 20 seconds to 1 hour (i.e., 3,600 seconds), 20 seconds to 50 minutes (i.e., 3,000 seconds), 20 seconds to 40 minutes (i.e., 2,400 seconds), 20 seconds to 30 minutes (i.e., 1,800 seconds), 20 seconds to 20 minutes (i.e., 1,200 seconds), 30 seconds to 1 hour (i.e., 3,600 seconds), 30 seconds to 50 minutes (i.e., It may be a step of heat treatment for 3,000 seconds), 30 seconds to 40 minutes (i.e., 2,400 seconds), 30 seconds to 30 minutes (i.e., 1,800 seconds), or 30 seconds to 20 minutes (i.e., 1,200 seconds). means of solving the problem

[0059] One aspect is (a) a step of manufacturing a fabric using polymer yarn;

[0060] (b) a step of treating the fabric manufactured above with a biodegradation promoting substance; and

[0061] (c) a step of fixing the above-mentioned treated fabric by heat treating it at 80°C to 300°C for 10 seconds to 1 hour; the present invention provides a post-treatment method for promoting the biodegradation of a fabric, comprising: (c) a step of fixing the above-mentioned treated fabric by heat treating it at 80°C to 300°C for 10 seconds to 1 hour.

[0062] Another aspect is the step of treating a polymer product with a biodegradation-promoting substance; and

[0063] The present invention provides a post-treatment method for promoting the biodegradation of a polymer product, comprising the step of fixing the above-mentioned treated polymer product by heat-treating it at 80°C to 300°C for 10 seconds to 1 hour. Effects of the invention

[0065] The post-treatment method for promoting the biodegradation of the fabric according to the present invention can further promote the biodegradation of the fabric and prevent the degradation of the fabric's biodegradation. Brief explanation of the drawing

[0067] Figure 1 is a diagram showing a method of applying the promoter of the present invention to a material. Figure 2 shows that the biodegradation rate of the fabric that underwent a fixation process after treatment with a biodegradation-promoting composition was maintained (Figure 2(B)), while the biodegradation-promoting effect of the fabric that did not undergo a fixation process decreased (Figure 2(A)). Figure 3 is a figure showing the light reflectance of CTO in a specific wavelength range. Figure 4 is a graph and photograph showing the transmittance spectra of polycarbonate plates with 0% and 0.05% IRASORB concentrations. Figure 5 shows the measured values ​​of (a) UV blocking, (b) visible light transmission, (c) IR blocking, and (d) solar heat gain coefficient in a PC plate in an empty state and in a state containing 0.05% and 0.1% of IRASORB CTO 20 and IRASORB CTO M10. Specific details for implementing the invention

[0068] The present invention will be explained in more detail below through examples and experimental examples. However, these examples are intended to illustrate the present invention, and the scope of the present invention is not limited to these examples and experimental examples.

[0070] Examples and Experimental Examples

[0071] Example 1. Biodegradation accelerator fixation technology

[0072] A knitted fabric was manufactured by applying knitting technology that enables a 3D structure capable of maximizing surface area while maintaining functionality by controlling the 3D structure, gauge (number of needles per unit length), and composition.

[0073] The above-mentioned knitted fabric was treated with a biodegradation-promoting composition comprising tungsten oxide-based nanomaterials, organic acids, and binders.

[0074] The above-mentioned treated fabric was heat-treated at 80°C to 300°C for 10 seconds to 1 hour to fix the components of the biodegradation-promoting composition to the surface of the fabric.

[0076] Example 2. Biodegradation inhibition prevention technology

[0077] 2.1. Removal of Legacy at the Organizational Level

[0078] (1) Weaving and knitting of fabric

[0079] 1) Fabric weaving method

[0080] The fabric was manufactured by weaving using polyester yarn.

[0081] Specifically, polyester yarns were prepared as warp and longitudinal yarns. An emulsion was uniformly applied to the prepared warp and longitudinal yarns.

[0082] Subsequently, the lubricated yarns were loaded onto a weaving machine. The warp yarns were loaded onto the machine using a shuttle method, while the warp yarns were fixed to a reference frame. The fixed warp and warp yarns were crossed to form the fabric. The finished fabric underwent a finishing process, followed by post-processing such as washing, drying, and ironing.

[0083] 2) Fabric knitting method

[0084] The fabric was manufactured by knitting using polyester yarn.

[0085] In the case of circular knitting fabrics, yarn was fed through various feeders (42 to 110 feeders) depending on the type of machine, and a raw circular knitting fabric was knitted.

[0086] In the case of warp-knitted fabrics, yarns were prepared on the beam, and guide yarns moved to knit the raw warp-knitted fabric.

[0088] (2) Removal of residual emulsion

[0089] 1) Physical cleaning method

[0090] The above-mentioned knitted polyester fabric with the oil was collected. The oil on the surface was removed by washing with a neutral detergent at 30°C to 50°C for 2 to 4 hours. After washing was completed, the fabric was rinsed thoroughly to ensure no residual detergent remained, and dried at room temperature for 24 hours.

[0091] 2) Chemical treatment method

[0092] The above-mentioned knitted polyester fabric with the oil was collected. The oil was removed by treating it with a detergent having a pH of 5 to 8 for 2 to 4 hours.

[0093] 3) Hot water washing method

[0094] The above-mentioned knitted polyester fabric with the oil applied was collected. The fabric was washed with hot water at 70°C to 120°C to remove the oil from the surface. After washing was completed, it was dried at 0°C to 10°C for 24 hours.

[0095] 4) Steam processing method

[0096] The above-mentioned knitted polyester fabric with the oil applied was collected. The fabric was treated with steam at 100°C to 120°C to remove the oil from the surface. After washing was completed, it was dried at 0°C to 10°C for 24 hours.

[0097] 5) Ultrasonic cleaning method

[0098] The above-mentioned knitted polyester fabric with the applied lubricant was collected. The lubricant was removed using fine vibrations with ultrasound ranging from 20 kHz to 100 kHz.

[0100] 2.2. pH Control and Surface Residue Removal During the Dyeing Step

[0101] (1) Fabric dyeing method

[0102] As described in 2.1 above, a fabric was manufactured using polyester yarn through knitting, and the fabric was washed to remove impurities.

[0103] An acid dye with a pH of 1 to 5 was prepared for dyeing the washed fabric. The acid dye and the fabric were placed in a dyeing machine and dyed by treating at 130°C to 150°C for 1 to 2 hours. Afterward, the fabric was rinsed in running water to remove residual dye and dried at 0°C to 10°C for 24 hours.

[0104] (2) pH adjustment and removal of surface residues

[0105] An alkaline adjusting agent was applied to the dyed fabric to adjust the pH. After treatment, the fabric was placed at room temperature for 10 to 15 minutes to adjust to a target pH range (e.g., 4.5 to 5.5).

[0106] After adjusting the pH as described above, the fabric was rinsed with running water to remove surface residues such as residual dye. This process was repeated 3 to 5 times. The rinsed fabric was laid flat or air-dried to remove moisture.

[0108] Experimental Example 1. Confirmation of fixation effect of biodegradation accelerator

[0109] In Example 1 above, the degree of biodegradation after 180 days was compared between a fabric with the biodegradation-promoting composition fixed and a fabric without the biodegradation-promoting composition applied to its surface.

[0110] As a result, it was confirmed that the biodegradation rate of the fabric that underwent a fixation process after treatment with a biodegradation-promoting composition was maintained, while the biodegradation-promoting effect of the fabric that did not undergo a fixation process decreased (see Fig. 2).

[0111] This result indicates that when a biodegradation promoter is fixed as a post-processing step, the components contained in the biodegradation promoter remain stably on the fiber surface, and the biodegradation rate can be maintained for a long time.

[0113] Experimental Example 2. Confirmation of effect preventing inhibition of biodegradation

[0114] 2.1. Verification of inhibition prevention effect when removing emulsifiers at the weaving stage

[0115] The degree of biodegradation after 180 days was compared between the fabric from which the lubricant was removed by each method during the knitting stage of Example 2.1 above and the fabric from which the lubricant was not removed (see Table 1).

[0116] Unremoved emulsion physical cleaning Chemical treatment hot water washing Steam processing Ultrasonic cleaning 75.5% 77.1% 76.7% 78.3% 78.1% 79.2%

[0117] 2.2. Confirmation of inhibition prevention effect during pH control and surface residue removal in the dyeing stage The degree of biodegradation after 180 days was compared between the fabric that underwent pH adjustment and surface residue removal during the dyeing step of Example 2.2 above and the fabric that did not undergo pH adjustment and surface residue removal (see Table 2).

[0118] Unremoved residue pH control Removal of surface residue pH adjustment and surface residue removal 75.5% 79.7% 84.1% 85.5%

[0119] Experimental Example 3. Application of products using polymers As described above, the post-processing method applicable to fabrics was also applied to other polymer products such as films, bottles, and plates.

[0120] As a result, it was confirmed that biodegradability increased in polymer products other than fabrics due to the immobilization of the biodegradation accelerator. This indicates that the biodegradation accelerator immobilization method of the present invention can be applied to other polymer products (see Table 3).

[0121] PET bottle PLA bottle PET plate PLA film 74.1% 72.3% 70.9% 71.5%

Claims

Claim 1 A post-treatment method for promoting the biodegradation of a fabric, comprising: (a) a step of manufacturing a fabric using a polymer fabric or knit; (b) a step of treating the manufactured fabric with a biodegradation-promoting substance; and (c) a step of fixing the treated fabric by heat-treating it at 80°C to 300°C for 10 seconds to 1 hour; wherein step (a) involves manufacturing a fabric by knitting a polymer fabric or knit yarn coated with an emulsion. Claim 2 A post-treatment method for promoting biodegradation of a fabric according to claim 1, wherein step (b) is performed by spraying a biodegradation-promoting composition comprising tungsten oxide-based nanomaterial, organic acid, and binder onto the fabric. Claim 3 A post-treatment method for promoting the biodegradation of a fabric, wherein the step (c) involves fixing tungsten oxide-based nanomaterials and organic acids to the fabric during the process in which the binder melts and then hardens. Claim 4 A post-treatment method for promoting the biodegradation of a fabric according to claim 2, wherein step (c) is a step of heat treatment at 150°C to 250°C for 30 seconds to 20 minutes. Claim 5 A post-treatment method for promoting the biodegradation of a fabric, wherein, in claim 1, (d) a step of removing the emulsion applied in step (a); further comprising Claim 6 A post-treatment method for promoting biodegradation of a fabric according to claim 5, wherein step (d) removes the emulsion by one or more methods selected from the following: i) washing with a neutral detergent at 30°C to 50°C for 2 to 4 hours; ii) treating the fabric with a detergent having a pH of 5 to 8 for 2 to 4 hours; iii) washing the fabric with hot water at 70°C to 120°C; iv) treating the fabric with steam at 100°C to 120°C; or v) treating the fabric with ultrasound at 20 kHz to 100 kHz. Claim 7 A post-treatment method for promoting biodegradation of a fabric, further comprising: (e) a dyeing step of treating the fabric with an acidic dye having a pH of 1 to 3 at 130°C to 150°C for 1 to 2 hours to color it. Claim 8 A post-treatment method for promoting the biodegradation of a fabric according to claim 7, further comprising the step of (f) treating with an alkaline adjusting agent to adjust the pH to 4.5 to 5.5 and rinsing the fabric 3 to 5 times with running water to remove surface residues. Claim 9 A post-treatment method for promoting the biodegradation of a polymer product, comprising: a step of treating a polymer product with a biodegradation-promoting substance; and a step of fixing the treated polymer product by heat-treating it at 80°C to 300°C for 10 seconds to 1 hour. Claim 10 A post-treatment method for promoting the biodegradation of a polymer product according to claim 9, wherein, in the step of treating the polymer product with a biodegradation-promoting substance, a biodegradation-promoting composition comprising tungsten oxide-based nanomaterials, organic acid, and a binder is sprayed onto a fabric.

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