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(11) | EP 4 800 181 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | COMPOSITION FOR PROMOTING BIODEGRADATION OF FABRIC AND POST-PROCESSING METHOD FOR PROMOTING BIODEGRADATION OF FABRIC USING THE SAME |
| (57) The present invention relates to a composition for promoting biodegradation, including
a tungsten oxide-based nanomaterial and an organic acid, a method for preparing the
same, and a fabric post-processing method using a biodegradation-promoting material.
Fabric post-processing using the composition for promoting biodegradation of the present
invention creates an environment in which hydrolysis of polymer fabrics may occur,
thereby promoting biodegradation while maintaining physical properties of the fabric,
such as strength.
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BACKGROUND
1. Field of the Invention
[0001] The present invention relates to a composition for promoting biodegradation of fabric and a post-processing method for promoting biodegradation of fabric using the same. Specifically, the present invention relates to a promoter for accelerating biodegradation, which accelerates the degradation of polymers constituting yarns and fabrics in the field of eco-friendly clothing manufacturing.
[0002] The present invention relates to a fabric post-processing method using a biodegradation promoter, and more specifically, to a fabric post-processing method using a biodegradation promoter for accelerating the degradation of biodegradable polyester in the field of eco- friendly clothing manufacturing.
2. Discussion of Related Art
[0003] Yarns and fabrics commonly used in everyday life are made from a variety of materials, including cotton, silk, wool, leather, and polyester. In particular, polyester, a widely used synthetic polymer, has high durability and excellent physical properties. Polyester is primarily used in the textile industry to manufacture clothing, bags, and various woven or knitted products. However, polyester does not easily biodegrade, causing environmental problems. Traditional polyester may take hundreds of years or more to degrade, and this is exacerbating the plastic pollution issue.
[0004] With the growing importance of environmental protection and sustainable development, research into biodegradable materials is actively underway. Biodegradation technology is a process of degrading and transforming polymers into harmless substances by natural microorganisms. This technology plays a crucial role in reducing waste and promoting resource recycling.
[0005] Existing synthetic fiber biodegradation technologies ensure biodegradability in the yarn manufacturing step, using modified polyethylene terephthalate (PET) polymerized or compounded with relatively easily biodegradable materials. The development of this yarn technology marked the beginning of overcoming the limitations of synthetic fibers like PET and nylon, which are a major source of environmental pollution due to their poor biodegradability. However, existing technologies have had the problem that properties such as strength were extremely low as they were inversely proportional to biodegradability, making commercialization impossible. In addition, the processing of these fibers into products significantly reduces their biodegradability.
[0006] Therefore, there is a growing need for technologies that enhance biodegradability through additional post-processing of manufactured fabrics and maintain biodegradability over long periods of time.
SUMMARY OF THE INVENTION
Composition for promoting biodegradation
[0007] In one aspect, the present invention provides a composition for promoting biodegradation of yarn or fabric, including 2% to 15% by weight of a tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and the remaining weight percent of water, based on the total weight of the composition.
[0008] In one specific example, the tungsten oxide-based nanomaterial is one or more tungsten oxide-based materials selected from the group consisting of cesium-tungsten-oxide (CTO), antimony-tungsten-oxide (ATO), tungsten trioxide (WO3), tungsten-copper oxide (CuWO4), tungsten-arsenic oxide (As2WO4), tungsten-iron oxide (Fe2WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4), having an average particle size of 30 nm to 70 nm.
[0009] However, when a dispersant or dispersing aid is included, particles may have a form in which a surfactant wraps around the surface of CTO, resulting in a particle size of 120 to 200 nm.
[0010] In one specific example, in addition to a tungsten oxide-based nanomaterial, tin oxide-based nanomaterials, such as indium tin oxide (ITO), may also be used.
[0011] In one specific example, 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.
[0013] In one specific example, the binder may be included in an amount of 2% to 15% based on the total weight of the composition.
[0015] In one specific example, the binder may be one or more selected from the group consisting of an acrylic latex/acrylic copolymer, polyethylene, a polyurethane dispersion (PUD), a water-based acrylic-polyurethane hybrid, and polyvinylpyrrolidone.
[0016] In one specific example, the composition may further include one or more components selected from the group consisting of a dispersant, a dispersing aid, a thickener, and an antifoaming agent.
[0017] In another aspect, the present invention provides a method for preparing a composition for promoting biodegradation of yarn or fabric, including steps of:
processing a tungsten oxide-based nanomaterial to an average particle size of 10 nm to 100 nm;
mixing 2% to 15% by weight of the tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and the remaining weight percent of water, based on the total weight of the composition; and
homogenizing the mixed mixture.
Fabric post-processing method to promote biodegradation through hydrolysis of the fabric
[0018] In still another aspect, the present invention provides a fabric post-processing method for promoting biodegradation through hydrolysis of the fabric, including steps of:
- (a) preparing a fabric manufactured using a polymer fabric or knitted fabric;
- (b) treating the fabric with a composition for promoting biodegradation including a tungsten oxide-based nanomaterial, an organic acid, and a binder; and
- (c) heat-treating the fabric treated with the composition for promoting biodegradation to fix the composition for promoting biodegradation.
[0019] In one specific example, the composition for promoting biodegradation may include 2% to 15% by weight of a tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and the remaining weight percent of water, based on the total weight of the composition for promoting biodegradation,
[0020] In one specific example, the tungsten oxide-based nanomaterial may be one or more tungsten oxide-based materials selected from the group consisting of CTO, ATO, tungsten trioxide (WO3), tungsten-copper oxide (CuWO4), tungsten-arsenic oxide (As2WO4), tungsten-iron oxide (Fe2WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4), having an average particle size of 30 nm to 70 nm.
[0021] In one specific example, 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.
[0022] In one specific example, the binder may be one or more selected from the group consisting of an acrylic latex/acrylic copolymer, polyethylene, a PUD, a water-based acrylic-polyurethane hybrid, and polyvinylpyrrolidone.
[0023] In one specific example, in Step (c), the fabric treated with the composition for promoting biodegradation may be heat-treated at 80 °C to 300 °C to fix the composition for promoting biodegradation.
[0024] In one specific example, in Step (c), the fabric treated with the composition for promoting biodegradation may be heat treated for 10 seconds to 1 hour to fix the composition for promoting biodegradation.
[0025] Specifically, Step (c) may be to fix the tungsten oxide-based nanomaterial and the organic acid to the fabric during a process of melting and hardening the binder.
[0026] Step (b) of treating the composition for promoting biodegradation may be to treat the composition for promoting biodegradation in one method selected from the group consisting of spraying, applying, immersing, coating, and depositing.
[0027] In one specific example, in Step (a) of manufacturing the fabric, the fabric may be manufactured by knitting or weaving polymer yarns to which an emulsion is applied.
[0028] In one specific example, Step (a) may further include a process of removing the applied emulsion from the manufactured fabric.
[0029] In one specific example, a method for removing the emulsion may be to remove the emulsion by one or more methods selected from the following methods:
- i) washing at 30 °C to 50 °C with a neutral detergent 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; and
- v) treating the fabric with ultrasonic waves at 20 kHz to 100 kHz.
[0030] In one specific example, Step (a) may further include a dyeing step of placing the manufactured fabric and a dispersed dye in a bath that has become slightly acidic at pH 4.0 to 5.5 by treatment with a pH adjuster (acid) and treating at 100 °C to 140 °C for 40 to 80 minutes to color the fabric.
[0031] In one specific example, the dyeing step further includes a final step of adjusting the pH to 6 to 9 by treating with an alkaline adjustor and rinsing the fabric three to five times with running water to remove a surface residue.
[0032] In yet another aspect, the present invention provides a fabric biodegradation method that promotes biodegradation through hydrolysis of the fabric, the method including a step of:
activating hydrolysis by irradiating the fabric with light having a wavelength of 300 nm to 2,500 nm, or under conditions of a temperature of 40 °C to 100 °C and a relative humidity of 60% to 100%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The above and other objects, features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:
FIG. 1 is a diagram illustrating the microbial degradation process of biodegradable fabric.
FIG. 2 is a diagram illustrating the light reflectance of cesium-tungsten-oxide (CTO) at specific wavelengths.
FIG. 3 shows a graph illustrating the transmittance spectra of polycarbonate (PC) plates with 0.05% and 0.05% IRASORB (trade name) concentrations and photographs of the plates.
FIG. 4 is a diagram illustrating the measured values of (a) UV blocking, (b) visible light transmittance, (c) IR blocking, and (d) solar heat gain coefficient for PC plates empty or containing 0.05% or 0.1% of IRASORB CTO 20 or IRASORB CTO M10.
FIG. 5 is a diagram illustrating the biodegradation of a material using a biodegradation promoter according to one embodiment of the present invention.
FIG. 6 is a diagram illustrating the results of examining the degree of dispersion of tungsten oxide-based nanomaterials according to the type of dispersant.
FIG. 7 is a diagram comparing the degree of biodegradation when a promoter is applied. FIG. 7A shows a standard sample, which exhibited no weight loss when not biodegraded, with a diameter of 13.2 µm and an area of 136.7 µm2. FIG. 7B shows a weight loss of 8.4% after 180 days of biodegradation without the application of a promoter, with a diameter of 12.7 µm and an area of 126.6 µm2. FIG. 7C shows a weight loss of 75.5% after 180 days of biodegradation with the application of a promoter, with a diameter of 6.55 µm and an area of 33.6 µm2.
FIG. 8 is a diagram illustrating a biodegradable fabric manufacturing process according to one embodiment of the present invention.
FIG. 9 is a diagram illustrating a post-processing method in which a biodegradation promoter of the present invention is applied to a fabric.
FIG. 10 shows photographs confirming that the biodegradation rate of a fabric that went through a fixation process after being treated with a composition for promoting biodegradation was maintained (FIG. 10B), but the biodegradation promotion effect of a fabric that did not go through a fixation process was reduced (FIG. 10A).
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
1. Definitions
[0034] The term "fiber" as used herein refers to the basic raw material for fabrics or knitwear, classified into natural fibers (e.g., cotton, wool, silk) and synthetic fibers (e.g., nylon, polyester). Fibers are very thin and long, and are the basic material for producing yarn.
[0035] The term "yarn" as used herein refers to a long string made by twisting multiple fibers. Fibers are combined to form yarn, which can be used to produce fabrics through weaving or knitting. Yarns may have various thicknesses, strengths, and textures.
[0036] The term "fabric" as used herein refers to a flat structure produced by weaving (or knitting) yarns. Fabrics may be used for various purposes, including clothing, accessories, home textiles, and knitwear. The properties of a fabric may vary depending on the type and arrangement of the yarns used.
[0037] The term "woven fabric" as used herein refers to a fabric produced by interweaving two or more yarns, and may include woven fabrics, knitted fabrics, circular knit fabrics, and flat knit fabrics.
[0038] The term "knitted fabric" as used herein refers to a fabric produced by interweaving yarns into loops, and may include warp knit fabrics, circular knit fabrics, and flat knit fabrics.
[0039] In the present invention, the term "biodegradable fabric" refers to a fabric that is naturally decomposed by microorganisms, such as polyester fabric (FIG. 1).
[0040] In the present invention, the term "tungsten oxide-based nanomaterial" refers to a material based on tungsten oxide (WOx) with a size ranging from 1 to 100 nm.
[0041] The term "organic acid" as used herein refers to a compound containing -OH and -COOH groups. In the present invention, the organic acid serves as a hygroscopic material to improve moisture content.
[0042] The term "binder" as used herein refers to a substance that helps the tungsten oxide-based nanomaterial and organic acid to be stably adhered on the surface of the fiber.
[0043] The term "dispersant" as used herein refers to a substance used to uniformly disperse solid particles in a liquid medium.
[0044] The term "dispersing aid" as used herein refers to a substance primarily used in conjunction with a dispersant to further promote uniform particle dispersion. A dispersing aid may act on the surface of particles to prevent agglomeration, assist the dispersant in uniformly distributing particles within the liquid medium, and control viscosity.
[0045] The term "thickening agent" as used herein refers to a substance that increases the viscosity of a liquid, making it thicker.
[0046] The term "anti-foaming agent (or defoamer)" as used herein refers to a substance used to suppress the formation of foams or bubbles within a liquid or to remove foams that have already been formed.
[0047] The term "spraying" as used herein refers to a method of discharging a liquid onto a solid surface in the form of fine particles or a spray. Typically, a spray gun or sprayer is used to evenly distribute and quickly apply the material to a surface.
[0048] The term "applying" as used herein refers to a method of directly applying a liquid to a solid surface using a brush, a roller, a sponge, or a similar device. The desired thickness and uniformity may be controlled.
[0049] The term "immersing" as used herein refers to a method of treating a solid object by immersing the same in a liquid. This method allows the liquid to be evenly brought into contact with all parts of the solid, resulting in an overall uniform treatment effect.
[0050] The term "coating" as used herein refers to a method of forming a protective film by applying a thin layer of liquid to a solid surface. Coating may be primarily used for purposes such as surface protection, durability enhancement, and aesthetic improvement.
[0051] The term "depositing" as used herein refers to a method of vaporizing a liquid and converting the same to a solid state on a solid surface to form a thin film. This process is typically carried out in a vacuum and may produce a very thin and uniform layer.
[0052] The term "emulsion" as used herein refers to an oil or chemical used in a yarn manufacturing process to reduce fiber friction and facilitate smooth machine operation. In a knitting process, the emulsion may help the yarns intersect smoothly and provide a lubricating function by reducing friction and preventing wear on the machine. Furthermore, the emulsion may coat the surface of fibers, preventing damage that may occur during a weaving process.
[0053] In the present invention, the term "fabric post-processing" refers to a process of manufacturing a biodegradable fabric by additionally treating the fabric with a composition for promoting biodegradation after dyeing the fabric and then further processing the fabric so that the composition for promoting biodegradation adheres well to the fabric.
1. Composition for promoting biodegradation
[0054] The present invention relates to a composition for promoting biodegradation of yarn or fabric. Specifically, the present invention relates to a material capable of maintaining the strength and other physical properties of the fabric by applying the composition for promoting biodegradation to the yarn or fabric, and then promoting biodegradation during subsequent landfilling for biodegradation.
[0055] The present invention provides a composition for promoting biodegradation including a tungsten oxide-based nanomaterial and an organic acid.
[0056] In one embodiment of the present invention, the composition for promoting biodegradation may be for promoting biodegradation of one or more selected from the group consisting of fibers, yarns, fabrics, woven fabrics, and knitted fabrics. In one specific example, the composition for promoting biodegradation may be for promoting fiber biodegradation, yarn biodegradation, fabric biodegradation, or knitted fabric biodegradation.
[0057] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may be one or more tungsten oxide-based materials selected from the group consisting of cesium-tungsten-oxide (CTO), antimony-tungsten-oxide (ATO), tungsten trioxide (WO3), tungsten-copper oxide (CuWO4), tungsten-arsenic oxide (As2WO4), tungsten-iron oxide (Fe2WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4), but is not limited thereto.
[0058] In one specific example, in addition to the tungsten oxide-based nanomaterial, a tin oxide-based nanomaterial, for example, indium tin oxide (ITO), may be used. In one embodiment of the present invention, the average particle size of the tungsten oxide-based nanomaterial may be 10 nm to 200 nm, 10 nm to 100 nm, 10 nm to 90 nm, 10 nm to 80 nm, 10 nm to 70 nm, 20 nm to 100 nm, 20 nm to 90 nm, 20 nm to 80 nm, 20 nm to 70 nm, 30 nm to 100 nm, 30 nm to 90 nm, 30 nm to 80 nm, or 40 nm to 50 nm.
[0059] In one embodiment of the present invention, the composition for promoting biodegradation may include 2% to 15% by weight, 2% to 14% by weight, 2% to 13% by weight, 2% to 12% by weight, 2% to 11% by weight, or 2% to 10% by weight, 2% to 9% by weight, 2% to 8% by weight, 2% to 7% by weight, 2% to 6% by weight, 2% to 5% by weight, 2% to 4% by weight, or 2% to 3% by weight of the tungsten oxide-based nanomaterial.
[0060] When the composition for promoting biodegradation is added at less than 2% by weight or more than 15% by weight, stability may be reduced.
[0061] The tungsten oxide-based nanomaterial of the present invention may have the above-described type and particle size, absorbing (shielding) light energy in a specific wavelength range, such as infrared, and may have high heat capacity so that greater thermal energy is secured at the fiber surface, thereby promoting fabric hydrolysis (FIGS. 2 to 5). As fabric hydrolysis is activated and the polymer fabric is changed to low-molecular weight molecules, biodegradation by microorganisms is promoted.
[0062] 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.
[0063] In one specific example, the organic acid may be glutaric acid or succinic acid, and may serve as a dispersing aid to facilitate stable dispersion of the tungsten oxide-based nanomaterial under processing solution conditions.
[0064] In the present invention, the organic acid serves to increase hydrophilicity on the fiber surface, thereby enhancing the fabric's very low wettability and moisture contact ability, so that moisture contact for hydrolysis is improved.
[0065] In one embodiment of the present invention, the organic acid may be glutaric acid, and may also be used as a dispersing aid to facilitate more stable dispersion of the tungsten oxide-based nanomaterial under processing solution conditions.
[0066] In one embodiment of the present invention, the composition for promoting biodegradation includes the aforementioned tungsten oxide-based nanomaterial, the organic acid, and the remaining weight percent of water.
[0067] In one embodiment of the present invention, during the process in which the tungsten oxide-based nanomaterial absorbs light in the wavelength range of 300 nm to 600 nm or 700 nm to 2,500 nm and increases the surface temperature, the organic acid may further enhance the hydrophilicity of the fiber surface, thereby exhibiting a synergistic effect.
[0068] In one embodiment of the present invention, when light in the wavelength range of 300 nm to 600 nm or 700 nm to 2,500 nm is incident on the tungsten oxide-based nanomaterial, vibration may occur in the nanomaterial due to the plasmon resonance effect, and this vibration is believed to contribute to thermal energy generation. Furthermore, the nanomaterial itself has a high heat capacity, enabling heat acquisition, which may affect the storage and generation of thermal energy.
[0069] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may absorb light in a wavelength range of 300 nm to 600 nm and generate thermal energy.
[0070] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may absorb light in a 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 generate thermal energy.
[0071] In one embodiment of the present invention, the composition for promoting biodegradation may include 2% to 20% by weight of an organic acid.
[0072] When the organic acid is added in an amount of less than 2% by weight, the hydrophilicity of the fiber surface may decrease, resulting in a reduced biodegradation rate. When the organic acid is added in an amount of more than 20% by weight, dispersibility may increase, but transparency and stability may deteriorate.
[0073] In one embodiment of the present invention, the composition for promoting biodegradation may further include a binder.
[0074] In one embodiment of the present invention, the binder may be adhered to the fabric surface at a temperature of 50 °C to 300 °C, 100 °C to 300 °C, 150 °C to 300 °C, 50 °C to 250 °C, 100 °C to 250 °C, 150 °C to 250 °C, or 150 °C to 230 °C.
[0075] In one embodiment of the present invention, the binder may be one or more selected from the group consisting of an acrylic latex/acrylic copolymer, polyethylene, a polyurethane dispersion (PUD), a water-based acrylic-polyurethane hybrid, and polyvinylpyrrolidone.
[0076] In the present invention, when heat energy is applied, the binder melts and adheres to the surface of the fabric, and thus causes a biodegradation-promoting material to adhere together and become fixed to the fabric, thereby enhancing the biodegradability of the fabric.
[0077] In one embodiment of the present invention, the composition for promoting biodegradation may include a binder in an amount of 2% to 15% by weight, 3% to 15% by weight, 4% to 15% by weight, 5% to 15% by weight, 6% to 15% by weight, 7% to 15% by weight, or 8% to 15% by weight, 9% to 15% by weight, or 10% to 15% by weight.
[0078] In one embodiment of the present invention, the composition may further include one or more components selected from the group consisting of a dispersant, a dispersing aid, a thickening agent, and an anti-foaming agent.
[0079] In one embodiment of the present invention, the composition for promoting biodegradation may include the dispersant at 0.01% to 5% by weight, 0.05% to 5% by weight, 0.1% to 5.0% by weight, or 0.1% to 3.0% by weight.
[0080] When the dispersant is added in an amount exceeding 5.0% by weight, the dispersion rate of the tungsten oxide-based nanomaterial and the organic acid may rather be reduced, and therefore, the optimal amount of the dispersant is 0.01% to 5.0% by weight.
[0081] In one embodiment of the present invention, the dispersant may include one or more components selected from the group consisting of an organic dispersant, an inorganic dispersant, a nonionic dispersant, an anionic dispersant, and a cationic dispersant.
[0082] In one embodiment of the present invention, the dispersant may include one or more of an acrylic polymer, water-soluble polyurethane, and polyethylene.
[0083] In one embodiment of the present invention, the organic dispersant may include one or both of palm oil and stearic acid.
[0085] In one embodiment of the present invention, the composition for promoting biodegradation may include a dispersing aid in an amount of 0.01% to 5% by weight, 0.05% to 5% by weight, 0.1% to 5.0% by weight, or 0.1% to 3.0% by weight.
[0086] When the dispersing aid is added in an amount exceeding 5.0% by weight, the dispersion rate of the tungsten oxide-based nanomaterial and the organic acid may rather be reduced, and therefore the optimal amount of the dispersing aid is 0.01% by weight to 5.0% by weight.
[0087] In one embodiment of the present invention, the dispersing aid may be selected from the group consisting of polyethylene glycol (PEG), a silane coupling agent (e.g., glycidoxypropyltrimethoxysilane), phosphonic acid, isopropanol, and polyvinyl pyrrolidone (PVP), but is not necessarily limited thereto, and any dispersing aid used in this technical field may be used without limitation.
[0088] In one embodiment of the present invention, the thickening agent may be selected from the group consisting of hydroxyethyl cellulose (HEC), xanthan gum, PVP, polyvinyl alcohol, and carboxymethyl cellulose (CMC), but is not necessarily limited thereto, and any dispersing aid used in this technical field may be used without limitation.
[0089] In one embodiment of the present invention, the composition for promoting biodegradation may include a thickening agent in an amount of 0.5% to 4.0% by weight, 0.5% to 2.0% by weight, or 0.5% to 1.0% by weight.
[0090] When the thickening agent is added in an amount exceeding 0.5% by weight, the dispersion rate of the tungsten oxide-based nanomaterial and the organic acid may rather be reduced. In one embodiment of the present invention, the anti-foaming agent may include one or more selected from the group consisting of an organic anti-foaming agent, an inorganic anti-foaming agent, and a natural anti-foaming agent.
[0091] In one embodiment of the present invention, the composition for promoting biodegradation may be characterized in that a tungsten oxide-based nanomaterial, an organic acid, and a binder are uniformly dispersed in a solvent.
[0092] In addition, the present invention provides a method for preparing a composition for promoting biodegradation, including:
a step of processing a tungsten oxide-based nanomaterial to an average particle size of 30 nm to 70 nm;
a step of mixing 2% to 15% by weight of a tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and 2% to 15% by weight of a binder; and
homogenizing the mixed mixture.
[0093] In one embodiment of the present invention, the method for preparing a composition for promoting biodegradation may further include a step of mixing one or more components selected from the group consisting of a dispersant, a dispersing aid, a thickening agent, and an anti-foaming agent.
[0094] The composition for promoting biodegradation of the present invention can promote biodegradation while maintaining the physical properties of the fabric, such as strength. The composition for promoting biodegradation has the advantage of allowing hydrolysis to occur under more favorable conditions.
[0095] The composition for promoting biodegradation prepared by the method for preparing the composition for promoting biodegradation of the present invention can exhibit excellent fabric biodegradability.
2. Fabric post-processing method for promoting biodegradation through hydrolysis of fabric
[0096] In another aspect, the present invention relates to a post-processing method capable of promoting biodegradation of a fabric while maintaining its physical properties, such as strength, by applying a material capable of promoting biodegradation of the fabric.
[0097] The devices and equipment used in the fabric post-processing according to embodiments of the present invention may be devices and equipment used in similar technical fields.
[0098] The present invention provides a fabric post-processing method for promoting biodegradation of the fabric, including steps of:
- (a) preparing a fabric manufactured using a polymer woven fabric or knitted fabric;
- (b) treating the manufactured fabric with a composition for promoting biodegradation; and
- (c) heat-treating the fabric treated with the composition for promoting biodegradation to fix the composition for promoting biodegradation.
[0099] In one embodiment of the present invention, in Step (c), the fabric treated with the composition for promoting biodegradation may be heat-treated at 80 °C to 300 °C to fix the biodegradation-promoting material.
[0100] In one embodiment of the present invention, in Step (c), the fabric treated with the composition for promoting biodegradation may be heat-treated for 10 seconds to 1 hour to fix the biodegradation-promoting material.
[0101] In one embodiment of the present invention, in Step (c), the tungsten oxide-based nanomaterial and the organic acid may be fixed to the fabric during a process of melting and hardening the binder. In one embodiment of the present invention, the biodegradation-promoting material may be for promoting biodegradation of one or more selected from the group consisting of a fabric, a woven fabric, and a knitted fabric. In one specific example, the biodegradation-promoting material may be for promoting biodegradation of a fabric, for promoting biodegradation of a woven fabric, or for promoting biodegradation of a knitted fabric.
[0102] In one embodiment of the present invention, the composition for promoting biodegradation may include 2% to 15% by weight, 2% to 14% by weight, 2% to 13% by weight, 2% to 12% by weight, 2% to 11% by weight, or 2% to 10% by weight of the tungsten oxide-based nanomaterial.
[0103] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may be one or more tungsten oxide-based materials selected from the group consisting of CTO, ATO, tungsten trioxide (WO3), tungsten-copper oxide (CuWO4), tungsten-arsenic oxide (As2WO4), tungsten-iron oxide (Fe2WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4), but is not limited thereto.
[0104] In one embodiment of the present invention, the average particle size of the tungsten oxide-based nanomaterial may be 10 nm to 100 nm, 10 nm to 90 nm, 10 nm to 80 nm, 10 nm to 70 nm, 20 nm to 100 nm, 20 nm to 90 nm, 20 nm to 80 nm, 20 nm to 70 nm, 30 nm to 100 nm, 30 nm to 90 nm, 30 nm to 80 nm, or 40 nm to 50 nm.
[0105] 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.
[0106] In one specific example, the organic acid may be glutaric acid or succinic acid, and may serve as a dispersing aid to facilitate stable dispersion of the tungsten oxide-based nanomaterial under processing solution conditions.
[0107] In the present invention, the organic acid serves to increase hydrophilicity on the fiber surface, thereby enhancing the fabric's very low wettability and moisture contact ability, so that moisture contact for hydrolysis is improved.
[0108] In one embodiment of the present invention, the organic acid may be glutaric acid, and may also be used as a dispersing aid to facilitate more stable dispersion of the tungsten oxide-based nanomaterial under processing solution conditions.
[0109] In one embodiment of the present invention, the composition for promoting biodegradation may include 2% to 15% by weight, 2% to 10% by weight, 2% to 5.0% by weight, or 2% to 3.0% by weight of the organic acid.
[0110] The tungsten oxide-based nanomaterial of the present invention may have the above-described type and particle size, absorbing (shielding) light energy in a specific wavelength range, such as infrared, and may have high heat capacity so that greater thermal energy is secured at the fiber surface, thereby promoting fabric hydrolysis.
[0111] In one embodiment of the present invention, during the process in which the tungsten oxide-based nanomaterial absorbs light in the wavelength range of 300 nm to 600 nm or 700 nm to 2,500 nm and increases the surface temperature, the organic acid may further enhance the hydrophilicity of the fiber surface, thereby exhibiting a synergistic effect.
[0112] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may absorb light in the wavelength range of 300 nm to 600 nm and increase the surface temperature.
[0113] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may 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.
[0114] In one embodiment of the present invention, the composition for promoting biodegradation may further include a binder.
[0115] In one embodiment of the present invention, the binder may be one or more selected from the group consisting of an acrylic latex/acrylic copolymer, polyethylene, a PUD, a water-based acrylic-polyurethane hybrid, and polyvinylpyrrolidone.
[0116] In one embodiment of the present invention, the binder may melt on the surface of the fabric at a temperature of 50 °C to 300 °C, 100 °C to 300 °C, 150 °C to 300 °C, 50 °C to 250 °C, 100 °C to 250 °C, 150 °C to 250 °C, or 150 °C to 230 °C.
[0117] In one embodiment of the present invention, the composition for promoting biodegradation may include the binder in an amount of 2% to 15% by weight, 2% to 14% by weight, 2% to 13% by weight, 2% to 12% by weight, 2% to 13% by weight, 2% to 12% by weight, or 2% to 11% by weight.
[0118] In one specific embodiment, when the binder melts, it may be crosslinked or fixed to the fabric. In one specific example, when heat energy is applied, the binder melts and adheres to the surface of the fabric, and thus causes a biodegradation-promoting material to adhere together and become fixed to the fabric, thereby enhancing the biodegradability of the fabric.
[0119] In the present invention, when heat energy is applied, the binder melts and adheres to the surface of the fabric, and thus causes a biodegradation-promoting material to adhere together and become fixed to the fabric, thereby enhancing the biodegradability of the fabric.
[0120] In one embodiment of the present invention, the composition for promoting biodegradation may include 2% to 15% by weight of a tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and 2% to 15% by weight of a binder.
[0121] When the organic acid is added in an amount of less than 2% by weight, the hydrophilicity of the fiber surface may decrease, resulting in a reduced biodegradation rate. When the organic acid is added in an amount of more than 20% by weight, dispersibility may increase, but transparency and stability may deteriorate.
[0122] In one embodiment of the present invention, the treatment step may be performed at a temperature of 50 °C to 300 °C, 100 °C to 300 °C, 150 °C to 300 °C, 50 °C to 250 °C, 100 °C to 250 °C, 150 °C to 250 °C, or 150 °C to 230 °C.
[0123] Step (b) of treating the fabric with the composition for promoting biodegradation may be performed by processing the composition for promoting biodegradation by one method selected from the group consisting of spraying, applying, immersing, coating, and depositing.
[0124] In the present invention, when heat energy is applied, the binder melts and adheres to the surface of the fabric, and thus causes a biodegradation-promoting material to adhere together and become fixed to the fabric, thereby enhancing the biodegradability of the fabric.
[0125] In one embodiment of the present invention, the composition for promoting biodegradation may additionally include one or more components selected from the group consisting of a dispersant, a dispersing aid, a thickening agent, and an anti-foaming agent.
[0126] The weaker or more insufficient the surface fixation, the more likely it is that the biodegradation-promoting material will continuously fall off during consumer use, potentially reducing the effect of promoting biodegradation of the fabric during landfilling. Therefore, the technology for fixing the biodegradation-promoting material onto the fabric surface allows the materials contained in the biodegradation-promoting material to remain stably on the fiber surface, thereby maintaining the biodegradation-promoting effect.
[0127] By adjusting the temperature within the above-described range during a tentering process, the crystallinity of the fabric surface may be controlled. When the temperature is out of the above-described range, the crystallinity or smoothness of the fabric surface may increase, negatively impacting biodegradability.
[0128] In one embodiment of the present invention, Step (c) may be a fixing step of performing heat-treatment at 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 280 °C, 120 °C to 270 °C, 120 °C to 260 °C, 120 °C to 250 °C, 150 °C to 300 °C, 150 °C to 290 °C, 150 °C to 280 °C, 150 °C to 270 °C, 150 °C to 260°C, or 150 °C to 250 °C.
[0129] In one embodiment of the present invention, Step (c) may be a step of fixing by heat treatment 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., 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).
[0130] In one embodiment of the present invention, in Step (a) of manufacturing the fabric, the fabric may be manufactured by knitting or weaving polymer yarns coated with an emulsion.
[0131] In one embodiment of the present invention, the emulsion may be applied to the yarn or fabric by a spraying method or an immersing method.
[0132] In one embodiment of the present invention, Step (a) may further include a process of removing the applied emulsion from the manufactured fabric.
[0133] In one specific embodiment, the emulsion removal step may be i) removing the emulsion by washing the fabric at 30 °C to 50 °C with a neutral detergent for two to four hours.
[0134] In one specific embodiment, the emulsion removal step may be ii) removing the emulsion by treating the fabric with a detergent having a pH of 5 to 8 for two to four hours.
[0135] In one specific embodiment, the emulsion removal step may be iii) removing the emulsion by washing the fabric with hot water at 70 °C to 120 °C.
[0136] In one specific embodiment, the emulsion removal step may be iv) removing the emulsion by treating the fabric with steam at 100 °C to 120 °C.
[0137] In one specific embodiment, the emulsion removal step may be v) removing the emulsion by treating the fabric with ultrasound at 20 kHz to 100 kHz.
[0138] In one embodiment of the present invention, Step (a) may further include a dyeing step of treating the manufactured fabric with a dye at 100 °C to 140 °C for 40 to 80 minutes to color the fabric.
[0139] The dye used in the dyeing step may be a disperse dye. Disperse dyes are nonionic, fine-particle, insoluble dyes. When the dyeing temperature rises, the amorphous region of the polyester swells so that the dye diffuses into the polymer, resulting in effective dyeing.
[0140] In one embodiment of the present invention, the pH adjuster may be an acidic adjuster or a basic (alkaline) adjuster. In one specific example, the acidic adjuster may be acetic acid or formic acid, and the alkaline adjuster may be sodium hydroxide.
[0141] In one embodiment of the present invention, the final dyeing step may further include a step of adjusting the pH to 6 to 8 through reductive cleaning and neutralization using a pH adjuster and then rinsing the fabric with running water three to five times to remove surface residues.
3. Method for fabric biodegradation
[0142] The present invention relates to a method for biodegrading the fabric manufactured above. Specifically, the present invention relates to a fabric biodegradation method, further including a step of irradiating the manufactured fabric with light in the wavelength range of 300 nm to 2,500 nm, or activating hydrolysis under conditions of a temperature of 40 °C to 100 °C and a relative humidity of 60% to 100%, thereby promoting biodegradation through hydrolysis of the fabric.
[0143] According to one embodiment of the present invention, hydrolysis for biodegradation of the manufactured fabric in a landfill for disposal may be promoted. The hydrolysis may occur throughout the polymer fabric, and the overall molecular weight of the polymer fabric may be reduced as a result of hydrolysis.
[0144] In one specific embodiment, when a PET fabric manufactured according to the present invention is disposed of, hydrolysis for biodegradation of the fabric may be promoted (see Chemical Formula 1). For example, the conditions under which biodegradation of PET fabric begins to occur may be set to a temperature of 40 °C to 80 °C and a relative humidity of 60% to 100%.
[0145] In one embodiment of the present invention, the fabric biodegradation method may further include a step of irradiating the fabric treated with the biodegradation-promoting material with light in a wavelength range of 300 nm to 2,500 nm.
[0146] In one embodiment of the present invention, during the process in which the tungsten oxide-based nanomaterial absorbs light in the wavelength range of 300 nm to 600 nm or 700 nm to 2,500 nm and increases the surface temperature, the organic acid may further enhance the hydrophilicity of the fiber surface, resulting in a synergistic effect.
[0147] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may absorb light in a wavelength range of 300 nm to 600 nm and increase the surface temperature.
[0148] In one embodiment of the present invention, the tungsten oxide-based nanomaterial may absorb light in a 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 generate thermal energy.
[0149] In one embodiment of the present invention, the fabric biodegradation method may further include (d) a step of biodegrading the fabric treated with the biodegradation-promoting material, at a temperature of 40 °C to 100 °C and a relative humidity of 60% to 100%.
[0150] In one embodiment of the present invention, the fabric treated with the biodegradation-promoting material may be biodegraded at a temperature of 20 °C to 100 °C, 20 °C to 90 °C, 20 °C to 80 °C, 30 °C to 100 °C, 30 °C to 90 °C, 30 °C to 80 °C, 40 °C to 100 °C, 40 °C to 90 °C, 40 °C to 80 °C, 60 °C to 100 °C, or 60 °C to 80 °C. In one specific example, it was confirmed that the biodegradation-promoting material exhibited an excellent biodegradation effect when the fabric treated with the biodegradation-promoting material was biodegraded at a temperature of 60 °C to 80 °C.
[0151] In one embodiment of the present invention, the fabric treated with the biodegradation-promoting material may be biodegraded at a relative humidity of 30% to 120%, 30% to 110%, 30% to 100%, 40% to 120%, 40% to 110%, 40% to 100%, 50% to 120%, 50% to 110%, 50% to 100%, 60% to 120%, 60% to 110%, or 60% to 100%. In one specific example, it was confirmed that the effect of the biodegradation-promoting material was excellent when the fabric treated the biodegradation-promoting material was biodegraded at 60% to 100%.
[0152] By using the post-processing method for promoting biodegradation of the fabric of the present invention, biodegradation can be promoted while maintaining the physical properties of the polymer fabric, such as strength. The above post-processing method for promoting biodegradation has the advantage of improving biodegradability through post-processing of already manufactured fabrics, thereby reducing costs required for environmental conservation and clothing disposal.
EXAMPLES
[0153] Hereinafter, embodiments of the present disclosure will be described in detail with the following examples. However, the present disclosure is not limited to the examples explained. Rather, the examples are provided to sufficiently transfer the concept of the present disclosure to a person skilled in the art to thorough and complete contents introduced herein.
[0154] The devices and equipment used in the fabric post-processing according to embodiments of the present invention may be devices and equipment used in similar technical fields.
Example 1. Preparation of composition for promoting biodegradation
1.1. Step of processing tungsten oxide-based nanomaterial
[0155] A super bead mill, a nanopowder dispersion device, was used to disperse tungsten oxide (CTO) into a particle size of 30 to 80 nm. The dispersed CTO was dissolved in a solvent (distilled water) to form a homogeneous dispersion.
1.2. Step of mixing tungsten oxide-based nanomaterials and organic acid
[0156] The tungsten oxide-based nanomaterial was mixed with an organic acid, and the dispersibility of the resulting mixture was confirmed. The dispersion rate was measured using sieve analysis, and the stability was assessed using zeta potential measurement.
[0157] The residue rate was calculated using sieve analysis as follows:
Residue rate (%) = (Dry weight of fiber remaining on sieve / Dry weight of fiber initially
added) × 100
[0158] A higher dispersion rate means less fiber remaining on the sieve, so a low residue rate indicates good dispersibility. Specifically, the dispersibility was graded according to the following criteria:
Excellent: Residue rate less than 1%
Good: Residue rate 5% or less
Poor: Residue rate 10% or more
[0159] Zeta potential measurement was performed using a device (Zetasizer (trade name), Malvern Panalytical) that measures the electrical charge (potential) on the surface of dispersed fiber particles. When particles have the same charge, they repel each other, maintaining a stable dispersion. The dispersibility was graded according to the following criteria:
Excellent: ±30 mV or higher (e.g., +35 mV or -40 mV)
Good: ±20 mV to ±30 mV
Unstable (initiation of aggregation): ± 10 mV to ±20 mV
Very unstable (rapid aggregation): ±5 mV or less
[0160] After conducting approximately 100 tests under various conditions and concentrations, it was confirmed that the best dispersion and stability were achieved when a mixture of 0.1% to 15% by weight of CTO and 0.02% to 3.0% by weight of an organic acid (glutaric acid) was used.
[Table 1]
| CTO content (% by weight) | Glutaric acid content (% by weight) | Dispersion rate (residue rate) | Stability (zeta potential) |
| 0.05 | 1 | Poor | Unstable |
| 2.0 | 2.0 | Excellent | Excellent |
| 3.0 | 3.0 | Excellent | Excellent |
| 2.0 | 1.0 | Excellent | Unstable |
| 3.0 | 1.0 | Excellent | Unstable |
| 3.0 | 4.0 | Excellent | Excellent |
| 5.0 | 1.0 | Excellent | Unstable |
| 5.0 | 5.0 | Excellent | Excellent |
| 10 | 10 | Excellent | Excellent |
| 15 | 15 | Excellent | Excellent |
| 15 | 21 | Excellent | Unstable |
| 15 | 25 | Excellent | Unstable |
| More than 15 | More than 20 | Poor | Unstable |
1.3. Mixing ratio of tungsten oxide-based nanomaterial, organic acid, and binder
[0161] The tungsten oxide-based nanomaterial was mixed with an organic acid and a binder, and the dispersibility of the resulting mixture was examined. Experiments were conducted with varying dispersants depending on the binder. The binder and dispersant were selected to ensure proper mixing without conflicts between the three materials.
[0162] The experimental results confirmed that binders such as polyvinyl pyrrolidone, an acrylic polymer, polyethylene, and water-based polyurethane may be used to enhance dispersion stability and that a better effect may be achieved by mixing a dispersant.
[Table 2]
| Binder name | Advantage | Disadvantage |
| Polyvinylpyrrolidone | Excellent transparency and washability | Slightly stiff texture |
| Acrylic polymer | Excellent processability | Slightly stiff texture |
| Polyethylene | Excellent processability | Very stiff texture |
| Polyurethane | Excellent texture | Relatively poor eco-friendliness |
[0163] Since tungsten oxide-based nanomaterials are metal oxides with strong ionicity (+2), better dispersibility was confirmed when an anionic dispersant was used. Conversely, aggregation occurred when a cationic dispersant was used.
[0164] In addition, when polyethylene was used as a dispersant, cloudiness and lump formation occurred due to the high molecular weight (left side of FIG. 3), and when polyurethane was used, the nanomaterial did not disperse at all or lump formation occurred when shaken (right side of FIG. 3).
1.4. Material mixing step
[0165] The materials were mixed as shown in Table 3 below.
[Table 3]
| Component | Preparation Example 1 (% by weight) | Preparation Example 2 (% by weight) | Preparation Example 3 (% by weight) | Preparation Example 4 (% by weight) |
| CTO (54 nm) | 15 | 15 | 15 | 15 |
| Glutaric acid | 15 | 15 | 15 | 15 |
| Binder (polyvinylpyrrolidone) | - | 15 | - | 15 |
| Dispersant (poly-phenyl acrylate) | - | - | 3 | 3 |
| Dispersing aid (isopropanol) | - | - | 2 | 2 |
| Thickening agent (polyvinyl-pyrrolidone: PVP K30) | - | - | 1.5 | 1.5 |
| Distilled water | 70 | 55 | 64.5 | 49.5 |
| Total weight | 100 | 100 | 100 | 100 |
1.5. Homogenization step
[0166] The above-described mixture was homogenized using a stirrer, ultrasonic disperser, or reactor to prepare a composition for promoting biodegradation.
Example 2. Fabric degradation effect according to average particle size of tungsten oxide-based nanomaterial
[0167] In the tungsten oxide-based nanomaterial processing step of Example 1.1, the biodegradability of fabrics after 180 days was determined according to average particle size (see Table 4). Except that the CTO size was different, the preparation of the composition for promoting biodegradation was the same as in Example 1.
[Table 4]
| Average particle size | Biodegradability |
| Less than 30 nm | Difficult to achieve the particle size |
| 30 nm to 80 nm | 75.5% |
| More than 80 nm | 54.1% |
Example 3. Manufacturing of fabric to prevent biodegradation inhibition
3.1. Emulsion removal during knitting and weaving stage
(1) Weaving and knitting of fabrics
1) Fabric weaving method
[0169] A fabric was manufactured through weaving using polyester yarns. Specifically, polyester yarns were prepared as wefts and warps. An emulsion was evenly applied to the prepared wefts and warps. The emulsion-coated yarns were then loaded onto a weaving machine. Thereafter, the wefts were loaded onto the machine using a shuttle, and the warps were secured to a reference frame. The fixed wefts and warps were crossed to form a fabric. The finished fabric underwent finishing processes and the post-processing, including washing, drying, and ironing.
2) Fabric knitting method
[0170] A fabric was produced through knitting using polyester yarns. For circular knit fabrics, yarns were fed through various feeders (42 to 120 feeders) depending on the machine type, and raw circular knit fabrics were knitted. For warp knit fabrics, yarns were prepared on a beam, and raw warp knit fabrics were knitted as guide yarns moved.
(2) Removal of residual emulsion
1) Physical washing method
[0171] The knitted polyester fabric with the emulsion applied thereon was collected. The fabric was washed with a neutral detergent at 30 °C to 50 °C for two to four hours to remove the emulsion on the surface. After washing, the fabric was thoroughly rinsed to remove any remaining detergent and dried at room temperature for 24 hours.
2) Chemical treatment method
[0172] The knitted polyester fabric with the emulsion applied thereon was collected. The fabric was treated with a detergent at pH 5 to 8 for two to four hours to remove the emulsion.
3) Hot water washing method
[0173] The knitted polyester fabric with the emulsion applied thereon was collected. The fabric was washed with hot water at 70 °C to 120 °C to remove the emulsion on the surface. After washing, the fabric was dried at 0 °C to 10 °C for 24 hours.
4) Steam treatment method
[0174] The knitted polyester fabric with the emulsion applied thereon was collected. The fabric was treated with steam at 100 °C to 120 °C to remove the emulsion on the surface. After washing, the fabric was dried at 0 °C to 10 °C for 24 hours.
5) Ultrasonic cleaning method
[0175] The knitted polyester fabric with the emulsion applied thereon was collected. The emulsion was removed by fine vibration using ultrasonic waves at 20 kHz to 100 kHz.
3.2. pH adjustment and surface residue removal in dyeing stage
(1) Fabric dyeing method
[0176] As described in 2.1 above, a fabric was manufactured through knitting or weaving using polyester yarns, and the fabric was washed to remove impurities. A disperse dye (Synolon®) was prepared for dyeing the washed fabric. The disperse dye and fabric were placed in a dyeing machine and treated at 100 °C to 140 °C for 40 to 80 minutes to dye the fabric. The fabric was then rinsed in running water to remove any remaining dye and dried at 15 °C to 25 °C for 24 hours.
(2) pH adjustment and surface residue removal
[0177] To adjust the pH, the dyed fabric was treated with an alkaline adjustor. After treatment, the fabric was allowed to stand at room temperature for 10 to 15 minutes to adjust the pH to a target range (e.g., 4.5 to 5.5). After adjusting the pH as described above, the fabric was rinsed in running water to remove any surface residue, such as residual dye. This process was repeated three to five times. The rinsed fabric was laid flat or air-dried to remove moisture.
Example 4. Biodegradation-promoting material fixation technique
[0178] A knitted fabric manufactured using the method described in 3.1 of Example 3 was treated with the composition for promoting biodegradation described in Preparation Example 4. The treated fabric was heat-treated at 80 °C to 300 °C for 10 seconds to 1 hour to fix the components of the composition for promoting biodegradation to the fabric surface (FIGS. 8 and 9). A knitted or woven fabric treated with the composition for promoting biodegradation but not heat-treated was manufactured as Comparative Example 2.
Example 5. Confirmation of biodegradation-promoting material fixation effect
[0179] The degree of biodegradation of the fabrics to which the composition for promoting biodegradation of Manufacturing Example 4 was fixed was compared after 180 days with that of the fabric with the composition for promoting biodegradation applied on the surface but not fixed thereto (i.e., fabric that was not heat-treated at 80 °C to 300 °C).
[0180] As a result, the fabric that underwent the fixation process after the treatment with the composition for promoting biodegradation maintained its biodegradation rate, whereas the fabric that did not undergo the fixation process showed a decrease in the biodegradation-promoting effect (FIG. 10). This result indicates that when the biodegradation-promoting material is fixed by post-processing, the components contained in the biodegradation-promoting material remain stable on the fiber surface, thereby maintaining the biodegradation rate for a long time.
Example 6. Confirmation of effect of preventing biodegradation inhibition
6.1. Confirmation of effect of preventing biodegradation inhibition by emulsion removal during knitting stage
[0181] The degree of biodegradation after 180 days of treatment with the composition for promoting biodegradation was compared between the fabrics in which the emulsion was removed using different methods during the knitting stage of Example 2.1 and the fabric in which the emulsion was not removed (see Table 5).
[Table 5]
| Residual emulsion not removed | Physical washing | Chemical treatment | Hot waver washing | Steam treatment | Ultrasonic cleaning |
| 75.5% | 77.1% | 76.7% | 78.3% | 78.1% | 79.2% |
6.2. Confirmation of effect of preventing biodegradation inhibition during pH adjustment and surface residue removal during dyeing stage
[0182] The biodegradation rate of the fabrics that underwent pH adjustment and surface residue removal during the dyeing stage of Example 2.2 was compared after 180 days with that of the fabric that did not undergo pH adjustment and surface residue removal (see Table 6).
[Table 6]
| Residual emulsion not removed | pH adjustment | Surface residue removed | pH adjustment + surface residue removed |
| 75.5% | 79.7% | 84.1% | 85.5% |
Example 7. Confirmation of fabric degradation effect of biodegradation-promoting substance
[0183] At the Friend of Industry Technology Information Testing & Research Institute (FITI Testing & Research Institute, Seoul, Korea), the fabric manufactured in Example 1 (named YL-1300) using biodegradable 100% PET fabric (Huvis Ltd., Seoul, South Korea) was treated with the composition for promoting biodegradation and underwent a biodegradation test conducted for 180 days according to the biodegradation standard ISO-21701. The temperature during the treatment with the composition for promoting biodegradation was 200 °C. The fabric that was not treated with the composition for promoting biodegradation was designated Comparative Example 1.
[0184] As a result, the fabric that was not treated with the composition for promoting biodegradation exhibited a biodegradability of approximately 8.4%. However, the same fabrics to which the composition for promoting biodegradation of Preparation Examples 2 and 4 was applied exhibited biodegradability of 75.5% and 79.2%, respectively (see Table 7 and FIG. 7). Preparation Examples 2 and 4 were prepared by adding a binder. When heat energy is applied, the binder melts and adheres to the surface of the fabric, and thus causes a biodegradation-promoting material to adhere together and become fixed to the fabric, thereby enhancing the biodegradability of the fabric.
[0185] These results indicate that applying the composition for promoting biodegradation to the fabric not only prevents biodegradability inhibition but also enables actual biodegradation.
[Table 7]
| Classification | Biodegradability |
| Preparation Example 1 | 32.8% |
| Preparation Example 2 | 75.5% |
| Preparation Example 3 | 36.4% |
| Preparation Example 4 | 79.2% |
Example 8. Confirmation of fabric biodegradation effect depending on temperature conditions
[0186] The fabric was treated with the composition for promoting biodegradation of Preparation Example 4, and the degree of biodegradation was determined after 180 days at controlled temperatures (see Table 8). These results indicate that the biodegradation rate of the fabric treated with the biodegradation-promoting material may increase when biodegradation occurs at temperatures above 60 °C.
[Table 8]
| Temperature | Degree of biodegradation |
| Less than 60 °C | 0% |
| 60 °C to 80 °C | 75.5% |
| 80 °C | 86.7% |
Example 9. Confirmation of fabric biodegradation effect depending on humidity conditions
[0187] The fabric was treated with the composition for promoting biodegradation of Preparation Example 4, and the degree of biodegradation was determined after 180 days in controlled humidity conditions (see Table 9). These results indicate that the biodegradation rate of the fabric treated with the biodegradation-promoting material may increase when biodegradation occurs at the following humidity levels.
[Table 9]
| Humidity | Degree of biodegradation |
| Less than 60% | 48.0% |
| 60% to 100% | 75.5% |
Example 10. Confirmation of fabric biodegradation effect depending on treatment method
[0188] The fabric was treated with the composition for promoting biodegradation of Preparation Example 4 in various methods, and the degree of biodegradation after 180 days was determined (see Table 10). These results indicate that the biodegradation rate of the fabric may increase when post-processing is performed by spraying, applying, immersing, coating, and depositing methods. Among these, post-processing using immersing or coating methods resulted in the highest biodegradation rates, at 75.5% and 61.9%, respectively.
[Table 10]
| Treatment method | Degree of biodegradation |
| Spraying | 33.7% |
| Applying | 51.3% |
| Immersing | 75.5% |
| Coating | 61.9% |
| Depositing | 41.1% |
Example 11. Confirmation of fabric biodegradation effect depending on wavelength
[0189] The fabric was treated with the composition for promoting biodegradation of Preparation Example 4, and the wavelength of a temperature-and-humidity chamber equipped with a light source was controlled to determine the degree of biodegradation after 180 days (see Table 11). These results indicate that the biodegradation rate of the fabric may increase when the fabric treated with the biodegradation promoter is irradiated with light within the wavelength range below.
[Table 11]
| Wavelength | Degree of biodegradation |
| Less than 300 nm | 59.7% |
| 300 nm to 600 nm | 69.2% |
| 700 nm to 2500 nm | 75.5% |
| More than 2500 nm | Not applicable |
Example 12. Application to polymer products
[0190] As described above, the post-processing method applicable to fabrics was also applied to other biodegradable polymer products, such as films, bottles, and plates. As a result, it was confirmed that biodegradability increased with the fixation of the biodegradation-promoting material also in the polymer products in addition to the fabrics. These results indicate that the biodegradation-promoting material fixation method of the present invention may be applied to other polymer products (see Table 12).
[Table 12]
| PET bottle | PLA bottle | PET plate | PLA film |
| 74.1% | 72.3% | 70.9% | 71.5% |
[0191] As described above, although the embodiments have been described by the restricted drawings, various modifications and variations may be applied on the basis of the examples by those skilled in the art. For example, even if the described techniques are performed in a different order from the described method, and/or components such as a system, a structure, a device, a circuit, and the like described above are coupled or combined in a different form from the described method, or replaced or substituted by other components or equivalents, an appropriate result may be achieved.
1. A composition for promoting biodegradation of yarn or fabric, comprising 2% to 15%
by weight of a tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic
acid, and the remaining weight percent of water, based on the total weight of the
composition,
wherein the tungsten oxide-based nanomaterial is one or more tungsten oxide-based materials selected from the group consisting of cesium-tungsten-oxide (CTO), antimony-tungsten-oxide (ATO), tungsten trioxide (WO3), tungsten-copper oxide (CuWO4), tungsten-arsenic oxide (As2WO4), tungsten-iron oxide (Fe2WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4), having an average particle size of 30 nm to 70 nm, and
the organic acid is 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.
2. The composition of claim 1, further comprising a binder, wherein the binder is included
in an amount of 2% to 15% based on the total weight of the composition.
3. The composition of claim 2, wherein the binder is adhered to a fabric surface at 80
°C to 300 °C.
4. The composition of claim 1, further comprising one or more components selected from
the group consisting of a dispersant, a dispersing aid, a thickener, and an antifoaming
agent.
5. A method for preparing a composition for promoting biodegradation of yarn or fabric,
comprising steps of:
processing a tungsten oxide-based nanomaterial to an average particle size of 10 nm to 100 nm;
mixing 2% to 15% by weight of the tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and the remaining weight percent of water, based on the total weight of the composition; and
homogenizing the mixed mixture.
6. A fabric post-processing method for promoting biodegradation through hydrolysis of
the fabric, comprising steps of:
(a) preparing a fabric manufactured using a polymer fabric or knitted fabric;
(b) treating the fabric with a composition for promoting biodegradation including a tungsten oxide-based nanomaterial, an organic acid, and a binder; and
(c) heat-treating the fabric treated with the composition for promoting biodegradation to fix the composition for promoting biodegradation,
wherein the composition for promoting biodegradation includes 2% to 15% by weight of a tungsten oxide-based nanomaterial, 2% to 20% by weight of an organic acid, and the remaining weight percent of water, based on the total weight of the composition for promoting biodegradation,
the tungsten oxide-based nanomaterial is one or more tungsten oxide-based materials selected from the group consisting of cesium-tungsten-oxide (CTO), antimony-tungsten-oxide (ATO), tungsten trioxide (WO3), tungsten-copper oxide (CuWO4), tungsten-arsenic oxide (As2WO4), tungsten-iron oxide (Fe2WO6), tungsten-calcium oxide (CaWO4), and tungsten-magnesium oxide (MgWO4), having an average particle size of 30 nm to 70 nm, and
the organic acid is 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.
7. The fabric post-processing method of claim 6, wherein, in Step (c), the fabric treated
with the composition for promoting biodegradation is heat-treated at 80 °C to 300
°C to fix the composition for promoting biodegradation.
8. The fabric post-processing method of claim 6, wherein, in Step (c), the fabric treated
with the composition for promoting biodegradation is heat treated for 10 seconds to
1 hour to fix the composition for promoting biodegradation.
9. The fabric post-processing method of claim 6, wherein Step (c) is to fix the tungsten
oxide-based nanomaterial and the organic acid to the fabric during a process of melting
and hardening the binder.
10. The fabric post-processing method of claim 6, wherein Step (b) of treating the composition
for promoting biodegradation is to treat the composition for promoting biodegradation
in one method selected from the group consisting of spraying, applying, immersing,
coating, and depositing.
11. The fabric post-processing method of claim 6, wherein, in Step (a) of manufacturing
the fabric, the fabric is manufactured by knitting or weaving polymer yarns to which
an emulsion is applied.
12. The fabric post-processing method of claim 6, wherein Step (a) further includes a
process of removing the applied emulsion from the manufactured fabric.
13. The fabric post-processing method of claim 12, wherein a method for removing the emulsion
is to remove the emulsion by one or more methods selected from the following methods:
i) washing at 30 °C to 50 °C with a neutral detergent 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; and
v) treating the fabric with ultrasonic waves at 20 kHz to 100 kHz.
14. The fabric post-processing method of claim 6, wherein Step (a) further includes a
dyeing step of treating the manufactured fabric with a dye at 100 °C to 140 °C for
40 to 80 minutes to color the fabric.
15. The fabric post-processing method of claim 14, wherein the dyeing step further includes
a step of adjusting the pH to 4.5 to 5.5 by treating with an alkaline adjustor and
rinsing the fabric three to five times with running water to remove a surface residue.