Double wool biocomposite air filter material and production method thereof

Abstract

The goal of the present invention is to provide a double-wool biocomposite air filter material and production method thereof, which is fully biodegradable and can be processed and enriched from animal wool. The double wool biocomposite air filter material is composed of (a) a Micro-cotton blend layer of PPK microfibers produced by processing biocomposite pellets from washed and combed coarse wool, a diameter of up to 22±10 micrometers and spunbonded with washed and combed wool, and (b) a layer of PPK nanofibers with a diameter of 0.2-1 micrometers, produced by processing biocomposite pellets from washed and combed coarse wool.

Description

DESCRIPTIONSOLUTION NAMEDouble wool biocomposite air filter material and production method thereof.TECHNICAL FIELD

[0001] The present invention related to the light industry, especially to a double wool biocomposite air filter material for air purification and filtration and production method thereof.BACKGROUND ART

[0002] It is estimated that indoor air pollution is 2-5 times higher than outdoor air pollution [Non-patent literature 1]. Currently, the most commonly used HEPA (High Efficiency Particulate Air [filter]) filter in the world is discarded and landfilled annually, accounting for 6,000 tons each year [Non-patent literature 2] .

[0003] Hence, polyethylene (PET) and polypropylene (PP), the main raw materials for synthetic HEPA filters, are sources of microplastics that pollute soil and water [Non-patent literatures 3, 4], In particular, HEPA and other air filter materials containing synthetic fibers are difficult to recycle once contaminated, and they produce more toxic volatile compounds when burned [Non-patent literatures 5],

[0004] Therefore, finding an organic source for filtering small particles in the air is essential due to its impact on the environment and human health.

[0005] The most commonly used air filter materials in Mongolia and around the world, made of polyethylene and polypropylene, filter airborne pollutants in the following ways (Figure 5) [Non-patent literature material 6],

[0006] As shown in Figure 5, a microfilament air filter 50 is made up of multiple layers of fibers 51, typically with diameters ranging from several ten meter of micrometers. The airflow into the filter 50 is shown by rightwards 52.

[0006] Nanofiber air filter materials are commonly used filter materials made of fibers with a diameter of less than 1 micrometer, with an average diameter of 500 nanometers [Nonpatent literature 7] .

[0007] As shown in Figure 5, when air pollution particles 54-57 enter through these microfilaments 51, they are filtered by colliding with the microfilaments and slowing moving their speed (particle 54), being captured between the microfilaments 51 (particle 55), being attracted to the microfilaments 51a by electrostatic attraction (particle 57), and spreading between the microfilaments 51 by diffusion (particle 56).

[0008] In contrast to such synthetic materials, there are filters using organic materials. For example, a filter solution using animal wool has been widely used. Such wool filters are placed in the exhaust path of all types of chimneys and are filters that filter out harmful compounds from the smoke coming out of the chimney. This is a filter that is constructed by placing two layers of wool and / or felt filters with a thickness of 5-30 mm in a cylindrical body prepared according to the size of the chimney to be used for exhaust. A sheep wool filter for smoke filtration is known [Patent reference 1].

[0009] Also known is an air wool filter that can effectively filter fine particles based on the diameter and density of the fibers by weaving or non-woven methods of sheep wool [PatentReference 2] .

[0010] Also known is a sheep wool filter from the brand LANACO (trademark) (NewZealand). The main application of this filter is in the filter of a face mask [Non-patent literature 8], Australian Merino wool is the world's finest and most widely used sheep wool, with an average diameter of ultrafine fibers (Ultrafine), with an average diameter of 12.5-17.5 microns [Non-patent literature 9] .

[0011] The above-mentioned sheep wool filter for smoke filtration is not known to what extent it filters two sizes of airborne particles, and there is no information on the relative effect of the wool fibers used on its pollutants. The efficiency of air wool filters is determined by comparing the properties of the filter base material with its structure and content, but there is no information on how to make them useful in textile and non-textile ways.

[0012] The LANACO brand sheep wool filter is enriched with non-biodegradable polymers, so it will not fully biodegrade when disposed of as waste in a landfill [Non-patent literature material 10],

[0013] One of the indicators used to measure air quality, especially pollution, is the amount of particles present in the air or suspended in the air. Here, PM (particulate matter) 10, or particles with a diameter of up to 10 micrometers, is measured, and PM2.5, or particles with a diameter of up to 2.5 micrometers, is measured. Fine particles that pollute indoor air in buildings are usually PM 10 or smaller.

[0014] Commercial air filters (filters) usually use synthetic fibers with uniform diameters and are capable of filtering fine particles up to PM2.5. However, since these filters are made of a single layer of material for air filtration, all particles in the air from PM2.5 to PM 10 and largerare collected on the filter surface. This causes the total surface area of the filter material to decrease efficiency indicator.

[0015] The mechanisms for absorbing airborne particles are classified as depth and surface (membrane) filtration, depending on the filtration requirement (Figure 6) [Non-patent literature 11]. As schematically shown in Figure 6(a), depth filtration is a method of trapping particles 62 in the air stream in the middle of a filter 60 composed of fibrous fibers 61. As schematically shown in Figure 6(b), a membrane filter 63 is a method of trapping airborne particles 62 on the surface or outer surface of the filter and preventing further passage.

[0016] There are two main technologies for producing high-performance air filter materials designed to filter fine particles below PM 0.3: Structure-based and Interaction-based [Non-patent literature 12],Interaction-based approach

[0017] The interaction-based method is often used as an additive to synthetic polymers. When the fibers that make up the filter are electrically charged, they attract charged particles in the air and work on the principle that they are attracted to the body through electrical interactions.Structure-based approach 1

[0018] By mixing fibers with different structures and using layers of fibers with different structures, a structure-based filter is created. This is a technology that can be used not only on wool, but also on any organic wool or fiber as the main structure and enriched with other fibers.Structure-based approach 2

[0019] Another structural method is based on the layering of a fdter material enriched with biocomposite microfibers with a diameter of up to l±0.3 micrometers, and a single layer of finer, 0.2-1 micrometer diameter biocomposite nanofibers (referred to as PPK nanofibers) with a thickness of 0.2 - 5 mm.REFERENCE MATERIAL

[0020] Patent reference materialPatent reference material 1: 20-2016-0003373 20-0002604 2016.10.20 “A sheep wool filter for smoke ddicated”Patent reference material 2: 20-2021-0004559 20-0003409 2021.12.01 “A sheep wool filter for smoke detection”Non-patent literature materialNon-patent literature material 1: EPA's Report on the Environment (ROE), U.S. Environmental Protection Agency https: / / www.epa.gov / reportenvironment / indoor-air-qualityNon-patent literature material 2: BriivAir Purifier (The world’s most sustainable air filter made of natural materials) https: / / www.fivecreate.co.uk / project-lNon-patent literature material 3: Jing-Jie Guo, etc. "Source, migration and toxicology of microplastics in soil", Environment International, Vol. 137, Apr. 2020, 105263Non-patent literature material 4: Merlin N Issac & Balasubramanian Kandasubramanian, "Effect of microplastics in water and aquatic systems", Environmental Science and Pollution Research Vol. 28, p. 19544-19562 (2021).Non-patent literature material 5: Paul M. Lemieuxa, etc., "Emissions of organic air toxics from open burning: a comprehensive review", Progress in Energy and CombustionScience Vol.30 (2004), pl-32.Non-patent literature material 6: S. Han, J. Kim, S.H. Ko, Advances in air filtration technologies: structure-based and interaction-based approaches, Materials Today Advances, Volume 9, 2021, 100134, ISSN 2590-0498.Non-patent literature material 7: Wang, C., Wu, S., Jian, M. et al. Silk nanofibers as high-efficient and lightweight air filter. Nano Res. 9, 2590-2597 (2016).Non-patent literature material 8: https: / / lanaco.co.nz / filters / Non-patent literature material 9: https: / / merinos.com.au / australian-merino / Non-patent literature material 10: https: / / shop.lanaco.co.nz / pages / faqNon-patent literature material 11: Process Hygiene | Risk and Control of Airborne Contamination G.J. Curiel, H.L.M. Lelieveld, in Encyclopedia of Food Microbiology (Second Edition), 2014Non-patent literature material 12: S. Han, J. Kim, S.H. Ko, Advances in air filtration technologies: structure-based and interaction-based approaches, Materials Today Advances, Volume 9, 2021, 100134, ISSN 2590-0498.Non-patent literature material 13: Ye Bian, Shijie Wang, Li Zhang, Chun Chen, Influence of fiber diameter, filter thickness, and packing density on PM2.5 removal efficiency of electrospun nanofiber air filters for indoor applications, Building and Environment, Volume 170, 2020, 106628, ISSN 0360-1323.Non-patent literature material 14: Baneqee, S., Vishakha, K., Das, S. et al. Oxidative stress, DNA, and membranes targets as modes of antibacterial and antibiofilm activity of facile synthesized biocompatible keratin-copper nanoparticles against multidrug resistant uropathogens. World J Microbiol Biotechnol 38, 20 (2022).Non-patent literature material 15: Shiv Shankar, Jong-Whan Rhim, Eco-friendly antimicrobial nanoparticles of keratin-metal ion complex, Materials Science and Engineering: C, Volume 105, 2019, 110068, ISSN 0928-4931.Non-patent literature material 16: Dan Mogosanu, George; Mihai Grumezescu, Alexandru Carmen Chifiriuc, Mariana; Keratin-Based Biomaterials for Biomedical Applications, Current Drug Targets, Volume 15, Number 5, 2014, pp. 518-530(13)Non-patent literature material 17: Richard S. Carran, Arun Ghosh, Jolon M. Dyer, Modification of surface properties of wool fabric with linde type a nano-zeolite, Journal of Applied Polymer Science, Volume 132, Issue 32, 2015.Non-patent literature material 18: Shavandi A, Ali MA. Keratin based thermoplastic biocomposites: a review. Reviews in Environmental Science and Bio / Technology. 2019 Jun l;18:299-316.SOLUTION TO PROBLEM

[0021] The goal of the present invention provides to develop a double-wool biocomposite air filter material and production method thereof, which is fully biodegradable and can be processed and enriched from animal wool.

[0022] Another goal of the present invention provides to process thick fiber sheep wool to create a double-wool biocomposite air filter material and production method thereof.

[0023] Another goal of the present invention provides to develop a Double Wool Biocomposite Air Filter Material and production method thereof, which uses coarse sheep wool to process it, provides biocomposite fibers mixed with biopolymer compounds, and supplement fine sheep wool.ADVANTAGEOUS EFFECTS OF INVENTION

[0024] The present invention provides and enriches wool to produced a biocomposite air filter material that is 100% biodegradable.

[0025] The present invention addresses the shortcomings of known solutions, namely that they are not biodegradable and are a source of soil pollution.

[0026] The present invention uses the positively charged electromagnetic properties of the cuticle membrane of wool fibers, which can trap and filter some negatively charged volatile organic compounds in the air, to create a biocomposite air filter material that filters small particles in the air.

[0027] The present invention is an environmentally friendly solution that does not pollute the environment.SUMMARY OF INVENTION

[0028] The present invention is a double-layered biocomposite air filter material and production method thereof.

[0029] The double-layered wool biocomposite air filter material of the present invention consisting of: a first layer produced of microfibers made by processing biocomposite pellets made from washed and combed coarse wool with a diameter of until 22±10 micrometer, and a second layer made of nanofibers with a diameter of 0.2-1 micrometers made by processing biocomposite pellets made from washed and combed coarse wool.

[0030] The production method of double-layered wool biocomposite air fdter material of the present invention comprising of: a dehydrating step of consisting preparing washed and combed coarse wool to a size of less than 3mm, washing it in an aqueous solution of 0. 1% surfactant, and rinsing it with distilled water; a producing mixture step of mixing said dehydrated wool by washing a mixing device using a 30% sodium hydroxide solution, and adding sodium percarbonate to form; a step of extracting keratin, which is a solid phase, using a dehydrating device, from sheep wool of said mixture obtained from said mixing device; a step of preparing a dry mixture by mixing said extracted keratin with a PLA / PBAT (80:20) polymer mixture in a ratio of 90: 10; a step of preparing 10% solution by dissolving said dry mixture in a solvent with a ratio of ethyl acetate (EA) / dimethyl formamide (N,N-DMF) 7:3; a step of extracting biocomposite material by heating said solution in temperature of 75°C for 24 hours; a step of extracting biocomposite pellets using a twin-screw extruder at a speed of 200 rpm and in temperature of 175°C to uniformly harden said extracted biocomposite material; a step of extracting micro-fibers and nano-fibers from said biocomposite pellets; and a step of producing double-wool air filter material by ironing said micro-fibers and said nano-fibers at different temperatures depending on the thickness of material.

[0031] It is preferable that surfactant aqueous solution is 0.1 percent TWEEN 80.

[0032] It is preferable that the primary raw material is washed and combed coarse wool that meets the requirements of the MNS 6398:2020 standard.

[0033] It is preferable that to mix washed and dehydrated wool in a mixer equipment with 3% of the dry weight of 30% sodium hydroxide solution, then add 4.5% of the dry weight of the wool and mix for 4 hours.

[0034] The biocomposite pellets are PLA / PBAT / Keratin pellets made from sheep wool biocomposite materials, the microfibers are PPK microfibers, and the nanofibers are PPK nanofibers.

[0035] The present inveion has a step of producing said micro-fibers with a diameter of 1-5 micrometers by spinning said biocomposite pellets using a thermally controlled rotary spinning machine at a speed of 4500 rpm at a temperature of 175°C; and a step of producing a pre-filter by using a fluffing device combining said micro-fibers with fine Mongolian sheep wool or washed and combed wool with a diameter of up to 22±10 micrometers.

[0036] The present inveion has a step of producing nanofibers with a diameter of 0.2-1 micrometers by dissolving said biocomposite pellets in a solvent, and by using an electrospinning device spunning at high voltage, in which introduced said solution.

[0037] The present invention is based on the principle of the Air Wool Filter in Patent Reference 2, which is the phenomenon of sorting particles by size from large to small, and the depth filtration mechanism for trapping particles, based on the surface or membrane filtration mechanism, and using three structural and interaction methods to filter finer particles in large quantities. It is a method for producing a biodegradable two-layer wool biocomposite air filter material.

[0038] In the present invention, combines fine (12-22 pm) sheep wool with coarse (>160 pm) sheep wool, enriches it with biocomposite fibers mixed with biopolymer compounds, and then layers of finer-diameter biocomposite fibers on top of it, creating 100% biodegradable air filter biocomposite materials.

[0039] The majority of the composition of sheep wool (about 80%) is keratin, and the rest is made up of non-protein compounds, fats and mineral salts. About 40% of the protein compounds that make up sheep wool keratin are hydrophobic and about 60% are hydrophilic, which makes it able to filter many polar and non-polar organic aromatic compounds in the air, such as volatile organic compounds such as benzene, toluene and xylene. However, in terms of structure, Mongolian sheep wool is not suitable for other uses because it has a large number of coarse fibers, more than 160 microns, which makes it suitable for filtering fine solid particles within the pores as a result of physicochemical decomposition.

[0040] The technology uses naturally absorbent sheep wool to process and enrich it with biodegradable polymer compounds such as polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT), which refines the internal pore structure to create a biodegradable filter material that is competitive with high-efficiency particulate air (HEP A) filters available on the market.

[0041] The solution is a fleece air filter that uses two layers of materials with different filtration capabilities. The first layer, a Micro-cotton blend, meets the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRE) MERV (Minimum Efficiency Reporting Value) MERV13 standard (Table 1), and the second layer, a PPK nanofiber air filter, meets the MERV 17 standard for this category.Table 1. American Society of Heating, Refrigerating, and Air-Conditioning Engineers(ASHRE) MERV Standard Air Filter Material Properties

[0043] The air wool fdter of the present invention was tested in the utility model application number MN20-2021-0004559 fded by the applicant of the present invention. The ability of C2+C3 and B filters to filter PM0.3, which is fine particulate matter, was determined by the Korean Standards Compliance Laboratory, and the C2+C3 filter was 57.8% and the B filter was 12.5%.

[0044] The ability to filter fine particles is directly related to the fine diameter and high density of the air filter material [Non-patent literature 13], so the two types of filter materialswere developed and a production technology was developed to enrich them with higher filtration efficiency according to the graph shown in Figure 4.

[0045] In the present invention, coarse Mongolian sheep wool is subjected to alkali treatment in the industrial process to obtain semi-degradable keratin. This allows copper nanoparticles, zeolite, and activated carbon to be attached to the degradable structure to improve its functional properties, such as deodorizing, providing antibacterial properties, and absorbing more toxic compounds [Non-patent literatures 14 - 18],

[0046] The solution can be used to purify and filter air in buildings, industrial facilities, automobiles, heavy machinery, and household appliances.BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a diagram showing an example of production method for Double Wool Biocomposite Air Filter Material of the present invention.Figure 2 is a schematic diagram showing an example of the factory steps for manufacturing air filter materials of the present invention.Figure 3 is a schematic diagram of the structure of the double wool biocomposite air filter of the present invention.Figure 4 is a graph showing the results of an experimental test to determine the method of manufacturing air filter materials based on their ability to filter PM 0.3 air pollutants.Figure 5 is a schematic diagram explaining the mechanism for filtering airborne particles.Figure 6 is a schematic diagram showing the working principle of deep (Figure (6a)) and surface (Figure (6b)) (membrane) filtration.DESCRIPTION OF EMBODIMENTS

[0048] The present invention is a double -layered wool biocomposite air filter material and production method thereof, which provides wool and has a double structure.

[0049] The present invention's Double Wool Biocomposite Air Filter Material is a solution that combines two methods used to produce air filter materials: Structure-Based and Interaction-Based.

[0050] This solution uses pure wool for its Double Wool Biocomposite air filter material, and the waste generated after using the final product is fully biodegradable, making it an environmentally friendly solution.

[0051] In this solution, coarse-fiber sheep wool is defined as wool with a diameter of 160 microns or more. Fine-fiber wool is defined as wool with a diameter of up to 22±10 microns.

[0052] In this solution, coarse wool waste is subjected to physical and chemical processing to produce Keratin semi-degradation and mixed with biodegradable polymer compounds such as polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) to produce biocomposite pellets (PLA / PBAT / Keratin - PPK). After that, the biocomposite pellets are produced using two types of fiber production technologies: PPK microfibers with a diameter of 1-5 micrometers and PPK nanofibers with a diameter of 0.2-1 micrometers. PPK microfibers are enriched with fine sheep fibers or washed and combed wool with a diameter of up to 22±10 micrometers, and a pre-filter called Micro-cotton blend is produced using a fluffing device. The thickness of the material can be adjusted depending on the application. PPK nanofibers are usedin layers of 0.2 - 5 mm thick and can be used alone or in layers with Micro-cotton blend depending on the application.

[0053] Figure 3 schematically shows the structure of the double wool biocomposite air fdter 20 of the present invention. Here, the fdter 20 consists of a first layer 21 of a Micro-cotton blend (PPK fibers 23 mixed with cotton) and a second layer 22 of PPK nanowool fibers 24. The first layer 21 has a looser fiber structure on the outside, or the side where air enters from the outside (see section 21a), and a denser one on the inside (see section 21b).

[0054] The flow of air from the outside is shown by arrow 25, and the flow of air from the outside is shown by arrow 27. The flow of air between the layers is also shown by arrow 26. As the air flows through the first layer 21 and the second layer 22, the particles 28, 28a, 28b, 28c contained in it are trapped by the fibrous fibers, and the purified air flows out of the filter.

[0055] The air entering from outside enters the first layer 21 from the outside, and since the fibers are sparse at the entrance, coarse particles (dirt) are trapped here (Example: particles 28a). As the air flows inward, the fibers become denser, so the particles that are trapped become smaller (Example: particles 28b).

[0056] The second layer 22 is made of PPK nanofibers 24, which are finer and denser, and are designed to filter small particles. Here, it is capable of filtering small particles up to PM 0.3.

[0057] Sheep wool itself has the property of being neutrally charged. Therefore, it is a condition for trapping some charged small molecules. Furthermore, coarse Mongolian sheep wool (also known as sable, goat hair, etc.) with a size of >160 microns was subjected to physicochemical processing and mixed with biopolymers (Polylactic acid - PLA, Polybutyleneadipate terephthalate - PBAT) to produce biocomposite microfibers (called PPK microfibers) with a diameter of up to l±0.2 micrometers. This has the advantage of allowing the formation of keratin composites to incorporate some metals such as copper and silver, thereby allowing them to exhibit antibacterial activity and other functional properties.

[0058] Mammalian hair is a fine-grained material, and its internal structure is made up of protein. It is used to create a dense air-filtering material. Also, the cuticle membrane of the outer structure, which is one of the hair fibers, has a positive electromagnetic property, so it can trap and filter some negatively charged volatile organic compounds in the air.

[0059] Therefore, using sheep's wool as a material to filter small particles in the air is not only beneficial for air filtration due to the structural properties of wool, but also an environmentally friendly solution that does not pollute the environment.

[0060] This solution is a combination of two methods: a depth filter and a membrane filter. A depth filter is a filter material with a structure that is more efficient and capable of absorbing or collecting more particles than a membrane filter.

[0061] The general technological scheme of the method for producing the Double Wool Biocomposite Air Filter Material of the present invention is shown in the diagram in Figure 1.

[0062] To produce double-layered wool biocomposite air filter material, the raw material, wool, is first prepared (Step 1).

[0063] In the present invention, coarse sheep wool is used as an example of wool. If it performs the same function as the coarse sheep wool used in this solution, other animal wools can be used, such as cashmere. For example, coarse sheep wool can be used.

[0064] The raw material is washed and combed coarse wool that meets the requirements of the MNS 6398:2020 standard, cut to a size of less than 3 mm, washed in a 0.1% TWEEN 80 solution, rinsed with distilled water and dehydrated (Step 2). The Tween 80 solution is an aqueous solution of surfactants. There, a different type meets the requirements.

[0065] The wool is then cleaveg with alkali (Stage 3). Here, the washed and dehydrated wool is put into a mixing device, 3% of the dry weight of 30% sodium hydroxide solution is added and mixed thoroughly. After that, 4.5% of the dry weight of the wool is added and mixed for 4 hours. The mixture in the mixing device is put into a dehydrator to extract the solid phase, the keratin of the sheep wool.

[0066] Prepare a 10% solution by adding PLA (Polylactic acid) and PBAT (Polybutylenadipate-terephthalate) (Step 4, Step 5).

[0067] There, the keratin obtained in the above step is mixed with a PLA / PBAT (80:20) polymer blend in a ratio of 90: 10 to prepare a dry mixture (Step 4, Step 5).

[0068] is dry mixture was dissolved in ethyl acetate (EA) / dimethyl formamide (N,N- DMF) 7:3 solvent (hereinafter referred to as “(E7:D3) solvent”) to prepare a 10% solution. The solution was stirred at 75°C for 24 hours to obtain the biocomposite material.

[0069] To uniformly solidify the extracted biocomposite material, it is placed in a twin- screw extruder at a speed of 200 rpm and a temperature of 175°C to produce PLA / PBAT / Keratin pellets of sheep wool biocomposite material (Step 6). Otherwise, it is pelleted

[0070] After that, the wool pellet biocomposite material is spun into filaments, using two methods: centrifugal force spinning and electrospinning (Step 7, Step 11). These two methodsproduce two different types of by-products from the biocomposite pellets: PPK microfilaments and PPK nanofilaments (Step 7a, Step I la).PPK micro fiber

[0071] First, we will explain the centrifugal force spinning of PPK microfilaments (Steps 7 to 10). The pelleted sheep wool biocomposite material is spun into fdaments at a suitable speed using a thermally controlled rotary spinning machine. For example, the processed sheep wool biocomposite material is spun into PPK microfilaments or biocomposite filaments with a diameter of 1 to 5 micrometers using a thermally controlled rotary spinning machine at a speed of 4500 rpm and a temperature of 175°C (Step 7a).

[0072] The biocomposite yam obtained is combined with fine Mongolian sheep wool or washed and combed wool with a diameter of up to 22±10 micrometers and spun (Step 8, Step 9). Here, the biocomposite yam is combined with fine wool and mixed in a spinning device to produce a micro-cotton blend or pre-filter (Step 10). The thickness of the micro-cotton blend is produced in a suitable amount, depending on the application, from thick to thin.PPK nanofiber

[0073] Let us briefly explain the production of PPK nanofibers. The processed sheep wool biocomposite is dissolved in a solvent (e.g., ethyl acetate (EA) / dimethyl formamide (N,N-DMF) in a ratio of 7:3), and the solution is fed into an electrospinning device and spun to obtain PPK nanofibers (Step 11, Step I la). The electrospinning device is operated at high voltage (e.g., 90 kW) to spin and produce biocomposite nanofibers with a diameter of 0.2 to 1 micrometer. The biocomposite nanofibers are formed into a filter with a certain thickness and a certain shape.

[0074] There is also a process of ironing and molding the above-mentioned Microcotton blend pre-filter and Biocomposite nano-fiber filter (Step 12). Here, since the product is to be a filter, the Micro-cotton blend pre-filter and Biocomposite nano-fiber filter are ironed with a hot iron, which can be under pressure, and ironed to obtain an air filter material (Step12). During ironing, the temperature is different depending on the thickness of the material, and thus the wool air filter material is ready.

[0075] This extracted air filter material has a thickness of 0.2-5mm and is comparable in efficiency to a MERV 17 HEPA filter.

[0076] There, the air filter material is a flat material of a certain thickness, which is cut according to the application, inserted into a filter mold, and the final product is produced (Step13).Production steps

[0077] An example of the process flow for Plant 1, which produces air filter materials of the present invention, is schematically shown in Figure 2.

[0078] The raw wool is washed and cleaned in Washing Device 2. The capacity of Washing Device 2 will vary depending on the amount of raw material used. For example, Washing Device 2 can wash 15 kg of dry wool in one wash. Before putting the wool into Washing Device 2, check for mechanical impurities and separate them from mechanical impurities. Put the wool into the washing device and add a 0.1% solution of TWEEN 80. TWEEN 80 is a solution of Polyoxyethylene (20) Sorbitan Monooleate or Polysorbate 80, which is an aqueous solution of surfactants.

[0079] The washing device 2 may be a manual washing tub or an automatic washing machine. The washing device 2 is responsible for washing and cleaning the wool and also for sterilizing it. The washing and sterilizing process depends on the size of the wool and takes approximately 30 minutes for the above-mentioned size.

[0080] The wet wool washed and disinfected by the washing device 2 is placed in the dewatering device 3 and the water is drained. The dewatering device 3 is a device that has a rotating cylindrical (vertical or horizontal) pulley and separates water (liquid) by centrifugal force. It may also be a device that squeezes the wool to remove water.

[0081] The dewatering device can be a large or small drum device depending on the size of the wool, for example, up to 25 kg of wet wool can be dewatered in 10 minutes in a single operation.

[0082] To completely dry the wet wool coming out of the dewatering device 3, it is fed into the drying device 4 and dried. The drying device 4 may be a device that operates on the condensation principle or an electric dryer with a heat pump.

[0083] The drying device 4 can, for example, dry up to 15 kg of damp wool in a single operation in 30 minutes.

[0084] The washed and dried wool is then shredded for further chemical processing. Here, the Cutting Device 5 is used to cut and shred the wool to a particle size of less than 3.0 mm. The Cutting Device 5 is suitable if it has a capacity of cutting up to 50 kg of wool per hour.

[0085] As mentioned above, the wool is still somewhat damp, even though it has been dried. To chemically treat this damp wool, place it in Tank 6, add 30% sodium hydroxidesolution (3.0% of dry wool), and mix thoroughly. Then, place it in Tank 7, add 4.5% technical soda to dry wool, and chemically treat it for 4 hours, stirring and mixing to form a paste.

[0086] This mixture is pumped from Tank 7 to Dewatering Device 8, where keratin is separated. Dewatering device 8 may be a device that operates on the principle of centrifugal force or on the principle of pressure.

[0087] Then, the raw material (keratin) from the Dehydration Device 8 is introduced into the Drying Device 9 and completely dried. The Drying Device 8 may be a device that operates on the condensation principle or an electric dryer with a heat pump.

[0088] Take 10% of the dried keratin and 90% of the PLA / PBAT polymer mixture and put them in the Dry Mixer 10. Add 10 times the amount of the E7:D3 solution mixture and mix at 75°C for 24 hours to obtain a biocomposite material. This is then put into the Granulator 11 to obtain a biocomposite pellet.

[0089] The pellet mill 11 is a device that operates on the principle of a twin-screw extruder.

[0090] The extracted PPK mixture is placed in a spinning device 12 for spinning under the action of centrifugal force to produce artificial cotton.

[0091] In this part of the technology, the polymer cotton and fine wool mixture produced is fed to Felting Line 13, a fully automated production line, for combing, combing, felting, and cutting.

[0092] The felting line 13 is a fully automatic line that uses a conveyor belt between each of these functions. Any width of conveyor belt can be used here, for example, the widely used 1300mm wide conveyor belt is used in this example.

[0093] In this felting line 13, fine wool and PPK polymer wool are mixed in a ratio of 80:20, and the mixed wool is evenly distributed on the line's conveying platform. The belt conveyor is preferably equipped with a magnetic surface to prevent metal parts from entering the equipment, and such a belt conveyor is used in this example. The mixed wool is transported by the belt conveyor and enters the felting device. The mixed wool from the felting machine is sucked by a pump and enters the feeding section of the combing machine. The wool from the combing device passes through the belt conveyor and enters the felting device. Here, the width and thickness of the felting material are preset. The felted loose material passes through the belt conveyor and enters a compactor with rollers heated to 200°C, and is compressed by rollers from both sides and compacted.

[0094] The material from the compactor is cut into a predetermined size by a cutting device via a belt conveyor. The cutting device winds the cut material around a rotating shaft and removes the air filter material (Step 14).

[0095] The resulting core-wrapped material will be used as air filter material, and it will be cut (cut and shredded) to the appropriate size for use to prepare the air filter.Experiment

[0096] The experiment established a method for producing air filter materials based on their ability to filter PM 0.3 air pollutants.

[0097] The results of this experiment are shown graphically in Figure 4.

[0098] The horizontal axis of the graph in Figure 4 shows the materials used in the experiment, here labeled B*, A3, C2+C3*, XI**, X2**, X3**, and X4**. The thickness of each material is indicated on the graph.

[0099] The vertical axis on the left of the graph shows the density of the materials used in the test, and the vertical axis on the right shows the ability to filter PM 3.0 particles.

[0100] Here, based on the results confirmed by experiments and analysis, new development options are marked as XI to X4.Y=4.11.82x-8.0911 ...( Formula 1)R2=l ...( Formula 2)Here:Y - PM0.3 Judicial competence, % x - material density, g / cm3R2- correlation coefficient y=-22. 148x+196.49 ...( Formula 3)R2=0.0007 ...( Formula 4)Here:Y - PM0.3 Judicial competence, % x - material thickness, mmR2- correlation coefficient

[0101] Here, based on the results of the experiment, Equation 1 - Equation 4 show how the filtration ability depends on the density and thickness of the material.Results[0 I 02] In the present invention, used domestic raw materials to produce a filter material that is completely biodegradable.

[0103] This fdter material can be mass-produced in many different types with different fdtration capabilities.

[0104] In the present invention, involves processing coarse sheep wool and mixing it with biopolymer compounds to produce biocomposite fibers, enriching fine sheep wool with it, and layering it with fmer-diameter biocomposite fibers, resulting in 100% biodegradable airpurifying biocomposite materials.

[0105] Filter material of the present invention combines both filter structure and interaction methods to produce an effective end product that filters airborne particles through both deep and surface (membrane) mechanisms.

[0106] This resulted in a biodegradable filter material that is competitive with high- efficiency particulate air (HEP A) filter materials available on the market.

Claims

CLAIMS1. Double-layered wool biocomposite air filter material consisting of: a first layer produced of microfibers made by processing biocomposite pellets made from washed and combed coarse wool with a diameter of until 22±10 micrometer, and a second layer made of nanofibers with a diameter of 0.2-1 micrometers made by processing biocomposite pellets made from washed and combed coarse wool.

2. Production method of double -layered wool biocomposite air filter material comprising of: a dehydrating step of consisting preparing washed and combed coarse wool to a size of less than 3mm, washing it in an aqueous solution of 0. 1% surfactant, and rinsing it with distilled water; a producing mixture step of mixing said dehydrated wool by washing a mixing device using a 30% sodium hydroxide solution, and adding sodium percarbonate to form; a step of extracting keratin, which is a solid phase, using a dehydrating device, from sheep wool of said mixture obtained from said mixing device; a step of preparing a dry mixture by mixing said extracted keratin with a PLA / PBAT (80:20) polymer mixture in a ratio of 90: 10; a step of preparing 10% solution by dissolving said dry mixture in a solvent with a ratio of ethyl acetate (EA) / dimethyl formamide (N,N-DMF) 7:3; a step of extracting biocomposite material by heating said solution in temperature of 75°C for 24 hours; a step of extracting biocomposite pellets using a twin-screw extruder at a speed of 200 rpm and in temperature of 175°C to uniformly harden said extracted biocomposite material;a step of extracting micro-fibers and nano-fibers from said biocomposite pellets; and a step of producing double-wool air filter material by ironing said micro-fibers and said nano-fibers at different temperatures depending on the thickness of material.

3. Production method of double-layered wool biocomposite air filter material according to claim 2, wherein a step of producing said micro-fibers with a diameter of 1-5 micrometers by spinning said biocomposite pellets using a thermally controlled rotary spinning machine at a speed of 4500 rpm at a temperature of 175°C; and a step of producing a pre-filter by using a fluffing device combining said micro-fibers with fine Mongolian sheep wool or washed and combed wool with a diameter of up to 22±10 micrometers.

4. Production methof of double-layered wool biocomposite air filter material according to claim 2, wherein a step of producing nanofibers with a diameter of 0.2-1 micrometers by dissolving said biocomposite pellets in a solvent, and by using an electrospinning device spunning at high voltage, in which introduced said solution.

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