Method for manufacturing biodegradable filter material, biodegradable filter material, air purification filter comprising same, and home appliance

Abstract

Provided are a method for manufacturing a biodegradable filter material, a biodegradable filter material, an air purification filter comprising same, and a home appliance, the method comprising the steps of: preparing a biodegradable resin blend by blending a biodegradable resin composition; preparing a melted biodegradable resin blend by increasing the temperature of the biodegradable resin blend; and preparing a biodegradable fiber member by spinning the melted biodegradable resin blend, wherein the biodegradable resin composition comprises a biodegradable resin and an additive, the additive includes a viscosity modifier, a charging agent or a combination thereof, and the melt flow rate (MFR) of the melted biodegradable resin blend, measured at 230°C according to ASTM D1238, is greater than 120 g / 10 min and less than or equal to 550 g / 10 min.

Description

Method for manufacturing biodegradable filter media, biodegradable filter media, air purification filters and home appliances containing the same

[0001] The present invention relates to a method for manufacturing a biodegradable filter, a biodegradable filter, an air purifying filter including the same, and a home appliance.

[0002] As the amount of plastic waste generated increases, its disposal is becoming increasingly important. Incineration of plastic waste contributes to air pollution through dust and toxic gases, and global warming through the release of large amounts of carbon dioxide. Landfilling of plastic waste also contributes to environmental pollution, including a shortage of landfill space and the un-decomposed nature of plastic waste. The need for plastic recycling is growing. For example, the use of recyclable polymers, such as biodegradable polymers, is being considered.

[0003] Plastics manufactured in nonwoven form are primarily used in consumables such as masks, filters, wet wipes, diapers, and dust bags. Nonwoven fabrics typically incorporate composite materials to meet the required physical and mechanical properties. Composite materials include, for example, non-biodegradable petroleum-based plastics in addition to biodegradable polymers. Therefore, they are classified as general waste rather than recyclable waste, making recycling difficult.

[0004] A recyclable, non-woven plastic material is required.

[0005] Air purification filters are used to remove fine dust. To provide dust collection performance, air purification filters incorporate media, such as meltblown media. Meltblown media require a more sophisticated manufacturing process than media manufactured through other methods. The meltblown process involves extruding molten resin through fine holes in a nozzle while supplying high-temperature air to form fibers. The molten resin must be able to withstand high temperatures while also exhibiting excellent flow properties. This excellent flow properties of the molten resin allow for a reduction in the diameter of fibers spun by air at high temperatures, facilitating the control of the mechanical properties of the meltblown media. If the molten resin becomes thermally deformed at high temperatures, spinning of the molten resin becomes impossible.

[0006] Meltblown media is typically manufactured using petroleum-based polymers with excellent melt flowability and thermal stability. Meltblown media can be manufactured by controlling the melt flowability of the molten petroleum-based resin to over 1,000 g / 10 min. Examples of such petroleum-based polymers include polyethylene, polypropylene, and polystyrene. However, these petroleum-based polymers have the disadvantage of being non-biodegradable.

[0007] Biodegradable resins, for example, have lower thermal stability and melt flow properties than petroleum-based resins, making them difficult to apply to the meltblown process. Nonwoven fabrics manufactured using biodegradable resins are used in applications such as wet wipes and masks, but their use is limited in applications requiring additional properties such as filtration efficiency, such as air purifiers. Therefore, there is a need for a method for manufacturing a filter medium using biodegradable resins while offering improved properties.

[0008] One aspect is to provide a method for manufacturing a novel biodegradable filter media which provides improved filtration efficiency and biodegradability.

[0009] Another aspect is to provide a novel biodegradable filter medium with improved filtration efficiency and biodegradability.

[0010] Another aspect is to provide an air purifying filter comprising the biodegradable filter medium.

[0011] Another aspect is to provide a home appliance comprising the above air purifying filter.

[0012] According to one aspect,

[0013] A step of preparing a biodegradable resin blend by blending a biodegradable resin composition;

[0014] A step of preparing a molten biodegradable resin blend by heating the biodegradable resin blend; and

[0015] A step of preparing a biodegradable fiber member by spinning the above-mentioned molten biodegradable resin blend,

[0016] The above biodegradable resin composition comprises a biodegradable resin and an additive, wherein the additive comprises a viscosity modifier, a charging agent, or a combination thereof,

[0017] A method for manufacturing a biodegradable filter material is provided, wherein the melt flow rate (MFR) of the above-mentioned melted biodegradable resin blend measured at 230°C according to ASTM D1238 is greater than 120 g / 10 min to 550 g / 10 min.

[0018] On another note,

[0019] Contains biodegradable fibers,

[0020] The above biodegradable fiber member comprises a biodegradable resin and an additive,

[0021] A biodegradable filter medium is provided, wherein the additive comprises a viscosity modifier, a charge regulator, or a combination thereof.

[0022] On another note,

[0023] An air purifying filter comprising a biodegradable filter medium according to the above is provided.

[0024] On another note,

[0025] Home appliances that include air purification filters are provided.

[0026] According to one aspect, a biodegradable filter medium having improved properties can be manufactured by controlling the melt flowability of a molten biodegradable resin blend.

[0027] The filtration efficiency and biodegradability of the biodegradable filter medium manufactured in this way can be improved.

[0028] Figure 1 is a flow chart of a method for manufacturing a biodegradable filter material according to an exemplary embodiment.

[0029] Figure 2 is a visual image of the biodegradable filter medium manufactured in Example 3.

[0030] Figure 3 is a schematic cross-sectional view of a filter having a biodegradable filter medium according to an exemplary embodiment.

[0031] Figure 4 is a schematic cross-sectional view of a filter having a biodegradable filter medium according to another exemplary embodiment.

[0032] Figure 5 is a schematic cross-sectional view of a filter having a biodegradable filter medium according to another exemplary embodiment.

[0033] The present disclosure described below is capable of various modifications and embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, but rather to encompass all modifications, equivalents, or alternatives falling within the technical scope of the present disclosure.

[0034] The terminology used below is only used to describe specific embodiments and is not intended to limit the present disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. Hereinafter, terms such as "comprises," "contains," or "has" are intended to indicate the presence of a feature, number, step, operation, component, part, ingredient, material, or combination thereof described in the specification, but should be understood to not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, ingredients, materials, or combinations thereof. In other words, the term "comprises" or "contains" in the present disclosure means including the target component or component without limitation of a specific aspect, and does not exclude the addition of additional components or components other than the target component or component. The " / " used below may be interpreted as "and" or "or" depending on the context.

[0035] In order to clearly express various layers and regions in the drawings, the thickness is shown enlarged or reduced. Similar parts are designated by the same drawing reference numerals throughout the specification. When a part such as a layer, film, region, or plate is said to be "on" or "above" another part throughout the specification, this includes not only cases where it is directly above the other part, but also cases where there is another part in between. Terms such as first, second, etc. may be used throughout the specification to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. In this specification and the drawings, components having substantially the same functional configuration are referred to by the same reference numerals, and redundant descriptions are omitted.

[0036] In this disclosure, "polylactic acid" refers to any polymer comprising repeating units formed by ring-opening polymerization of a lactide monomer. The polymer may be a homopolymer or a copolymer, and is not limited to the specific embodiment in which the polymer exists. For example, the polymer may include various embodiments, such as an unrefined or purified polymer after ring-opening polymerization is completed, a polymer included in a liquid or solid resin composition prior to product molding, or a polymer included in a plastic, film, or fabric after product molding is completed.

[0037] In the present disclosure, “lactide” includes L-lactide composed of L-lactic acid, D-lactide composed of D-lactic acid, and meso-lactide composed of L-lactic acid and D-lactic acid.

[0038] In the present disclosure, “poly-L-lactic acid (PLLA)” means a polymer comprising repeating units formed by ring-opening polymerization or direct polymerization of an L-lactide monomer.

[0039] In the present disclosure, “poly-D-lactic acid (PDLA)” means a polymer comprising repeating units formed by ring-opening polymerization or direct polymerization of a D-lactide monomer.

[0040] In the present disclosure, “polybutylene succinate (PBS)” means a polymer comprising repeating units formed by sequential polymerization of 1,4-butanediol and succinic acid.

[0041] In the present disclosure, “polycaprolactone (PCL)” means a polymer comprising repeating units formed by ring-opening polymerization of ε-caprolactone.

[0042] In this disclosure, “petroleum-based resin” means a resin or polymer manufactured using raw materials obtained from petroleum.

[0043] In this disclosure, “biodegradable resin” means a resin or polymer that is decomposed into water, carbon dioxide, etc. by microorganisms, etc.

[0044] In this disclosure, “non-biodegradable resin” means a resin or polymer that takes more than 100 years to decompose and is substantially non-degradable.

[0045] In the present disclosure, a “thermoplastic resin” is a resin whose flexibility increases as temperature increases.

[0046] In the present disclosure, the “weight average molecular weight” of a polymer is measured using gel permeation chromatography (GPC) and is a relative value to a polystyrene standard sample.

[0047] Hereinafter, a method for manufacturing a biodegradable filter according to exemplary embodiments, a biodegradable filter, an air purification filter including the same, and a home appliance are described in more detail.

[0048] A method for manufacturing a biodegradable filter medium according to one embodiment comprises the steps of: blending a biodegradable resin composition to prepare a biodegradable resin blend; heating the biodegradable resin blend to prepare a molten biodegradable resin blend; and spinning the molten biodegradable resin blend to prepare a biodegradable fiber member, wherein the biodegradable resin composition comprises a biodegradable resin and an additive, wherein the additive comprises a viscosity modifier, a charging agent, or a combination thereof, and wherein the melt flow rate (MFR) of the molten biodegradable resin blend measured at 230° C. according to ASTM D1238 is greater than 120 g / 10 min to 550 g / 10 min. The melt flow rate (MFR) of the molten biodegradable resin blend as measured at 230°C according to ASTM D1238 can be, for example, 121 g / 10 min to 550 g / 10 min, 150 g / 10 min to 550 g / 10 min, 200 g / 10 min to 550 g / 10 min, 250 g / 10 min to 550 g / 10 min or 300 g / 10 min to 500 g / 10 min.

[0049] A biodegradable filter medium that simultaneously provides improved filtration efficiency and biodegradability can be effectively manufactured by satisfying the range of melt flow rate (MFR) of more than 120 g / 10 min to 550 g / 10 min as measured at 230°C according to ASTM D1238 of the molten biodegradable resin blend. If the MFR is too low, the relative filtration efficiency of the biodegradable filter medium may be reduced due to an increase in the diameter of the biodegradable fibers manufactured in the spinning process. If the MFR is too high, the thermal stability of the biodegradable resin may be reduced, which may cause the biodegradable resin to be thermally decomposed. The possibility of defects occurring in the spinning process from the molten biodegradable resin blend including the thermally decomposed biodegradable resin increases.

[0050] Referring to Fig. 1, a method for manufacturing a biodegradable filter material according to one embodiment is described.

[0051] First, a biodegradable resin blend is prepared by blending a biodegradable resin composition.

[0052] A biodegradable resin composition includes a biodegradable resin and an additive. The additive includes a viscosity modifier, a charging agent, or a combination thereof. The biodegradable resin composition includes a biodegradable resin. By including the biodegradable resin in the biodegradable resin composition, the biodegradability of the biodegradable filter medium is improved. The biodegradable resin includes, for example, polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polyhydroxyalkanoates (PHA), polyhydroxybutyrate (PBH), cellulose, or a combination of two or more thereof. The biodegradable resin may be, in particular, polylactic acid.

[0053] The polylactic acid may be, for example, poly-L-lactic acid, which is made from L-lactide or L-lactic acid. The polylactic acid may be, for example, poly-D-lactic acid, which is made from D-lactide or D-lactic acid. The polylactic acid may be, for example, a mixture of poly-L-lactic acid and poly-D-lactic acid. The opposite steric structures of these may result in a stronger bond between them.

[0054] Polylactic acid is an aliphatic polyester containing repeating units of the following chemical formula 1, for example.

[0055] <Chemical Formula 1>

[0056]

[0057] In the above chemical formula 1, n is a number greater than or equal to 2. The acidity of the polylactic acid may be, for example, 50 meq / kg or less. The acidity of the polylactic acid is not limited to this range, but may provide further improved physical properties within this acidity range. For example, the acidity of the polylactic acid may be 1 to 50 meq / Kg, 1 to 30 meq / Kg, 1 to 10 meq / Kg, or 2 to 5 meq / Kg. The acidity of the polylactic acid may be measured, for example, according to ASTM D664.

[0058] The optical purity of the polylactic acid may be, for example, 90% or higher. The optical purity of the polylactic acid may be, for example, 93% or higher, 95% or higher, or 97% or higher. If the optical purity of the polylactic acid is lower than 90%, the mechanical properties of the biodegradable resin composition may deteriorate. The glass transition temperature (Tg) of the polylactic acid may be, for example, 50°C or higher. The glass transition temperature of poly-L-lactic acid (PLLA) is, for example, 55 to 68°C or 60 to 68°C. The glass transition temperature (Tg) of the polylactic acid may be measured using, for example, a Differential Scanning Calorimeter (DSC), a Dynamic Mechanical Analyzer (DMA), a Thermomechanical Analyzer (TMA), and / or a Thermogravimetric Analyzer (TGA).

[0059] Polybutylene succinate (PBS) is an aliphatic polyester containing repeating units of the following chemical formula 2, for example. In the following chemical formula 2, n is a number greater than or equal to 2.

[0060] <Chemical Formula 2>

[0061]

[0062] Polycaprolactone (PCL) is an aliphatic polyester containing repeating units of the following chemical formula 3, for example. In the following chemical formula 3, n is a number greater than or equal to 2.

[0063] <Chemical Formula 3>

[0064]

[0065] Biodegradable resins are, for example, biodegradable polymers. Biodegradable polymers are, for example, thermoplastic polymers.

[0066] The weight average molecular weight of the biodegradable polymer may be, for example, 10,000 to 500,000 Dalton, 100,000 to 300,000 Dalton, or 10,000 to 500,000 Dalton. The weight average molecular weight of the polylactic acid may be, for example, 10,000 to 500,000 Dalton, 100,000 to 300,000 Dalton, or 10,000 to 500,000 Dalton. If the weight average molecular weight of the biodegradable polymer is less than 10,000 Dalton, the heat resistance of the biodegradable resin composition may be excessively reduced. If the weight average molecular weight of the biodegradable polymer is more than 500,000, melting may be difficult. The weight average molecular weight can be measured using GPC (Gel Permeation Chromatography) for a polystyrene standard sample.

[0067] The biodegradable resin composition may include, for example, polylactic acid. The biodegradable resin composition may be free of, for example, a petroleum-based non-biodegradable resin. The biodegradable resin composition may not include a petroleum-based non-biodegradable resin. A petroleum-based resin is a resin or polymer obtained from petroleum. The petroleum-based non-biodegradable resin may be, for example, an olefin-based resin. The petroleum-based non-biodegradable resin may include, but is not limited to, polyethylene, polypropylene, polystyrene, etc., and any petroleum-based resin that is not biodegradable and is used in the art is generally used in combination with a biodegradable resin to enhance the properties of the biodegradable resin. In contrast, a biodegradable filter medium manufactured using the biodegradable resin composition of the present disclosure can provide excellent filtration efficiency and mechanical properties despite only including a biodegradable resin and not including a petroleum-based non-biodegradable resin.

[0068] The biodegradable resin composition comprises polylactic acid, and the polylactic acid content may be, for example, 95 wt% or more, 97 wt% or more, 98 wt% or more, or 99 wt% or more of the total weight of the biodegradable resin composition. The polylactic acid content may be, for example, 95 wt% to 99.9 wt%, 97 wt% to 999 wt%, 98 wt% to 99.9 wt%, or 99 wt% to 99.9 wt% of the total weight of the biodegradable resin composition.

[0069] The biodegradable resin composition may include a viscosity modifier as an additive. The viscosity modifier may include, for example, an organic peroxide-based viscosity modifier, a vinyl-based viscosity modifier, an acrylic-based viscosity modifier, or a combination thereof.

[0070] By including a viscosity modifier in the biodegradable resin composition, the diameter of a biodegradable fiber manufactured from the biodegradable resin composition can be more easily controlled.

[0071] Organic peroxide viscosity modifiers include, for example, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, ditert-butyl peroxide, ditert-amyl peroxide, tert-butyl cumyl peroxide, di(tert-butylperoxy-isopropyl)-benzene, dicumyl peroxide, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, 3,3,5,7,7-pentamethyl-1,2,4-trioxepane or a combination thereof. The organic peroxide-based viscosity modifier may be, for example, a reactive viscosity modifier that reacts with a biodegradable resin. The organic peroxide viscosity modifier may react with the biodegradable resin to scission the chain of the biodegradable resin, thereby improving the fluidity of the biodegradable resin composition. The reaction between the organic peroxide viscosity modifier and the biodegradable resin may be, for example, a radical reaction. The radical reaction may be, for example, a chain radical reaction. Therefore, by improving the fluidity of the biodegradable resin composition, the production of a biodegradable resin blend from the biodegradable resin composition and / or the spinning of a biodegradable fiber from the biodegradable resin blend may be more easily performed.

[0072] The vinyl-based viscosity modifier may include, for example, poly(vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate), fluoroethylene vinyl ether, 2-butenedioic acid (2Z)-, 1-(1-methylethyl) ester, N,N'-bis(2,2,6,6,-tetramethylpiperidin-4-yl)-1,3-dicarboxamide, or a combination thereof. The vinyl-based viscosity modifier may be blended with the biodegradable resin to adjust the viscosity of the biodegradable resin composition.

[0073] The acrylic viscosity modifier may include methyl methacrylate, butyl methacrylate, butyl methacrylate, butyl methacrylate, or a combination thereof. The acrylic viscosity modifier can control the viscosity of the biodegradable resin composition by blending it with the biodegradable resin.

[0074] The content of the viscosity modifier included in the biodegradable resin composition may be from more than 0 to 5 wt%, from more than 0.5 wt% to 4 wt%, from 0.6 wt% to 3 wt%, or from 0.6 wt% to less than 2 wt% of the total weight of the biodegradable resin composition. If the content of the viscosity modifier increases excessively, the fluidity of the biodegradable resin composition may increase excessively, thereby reducing the thermal stability of the biodegradable resin composition. Accordingly, thermal decomposition of the molten biodegradable resin blend obtained from the biodegradable resin composition may occur. As a result, it may be difficult to easily perform spinning of biodegradable fibers from the molten biodegradable resin blend.

[0075] The biodegradable resin composition may include a precipitant as an additive.

[0076] The charging agent may include, for example, a metal oxide charging agent, an imide charging agent, or a combination thereof.

[0077] By including a charging agent in the biodegradable resin composition, the biodegradable filter medium manufactured from the biodegradable resin composition can be more easily charged. The charged biodegradable filter medium can, for example, have positive charges placed on its surface. Therefore, particles with negative charges can be more easily adsorbed onto the surface of the charged biodegradable filter medium. Consequently, the filtration efficiency of the biodegradable filter medium can be further improved.

[0078] The metal oxide charge may include, but is not limited to, TiO2, SiO2, ZnO, SnO2, or a combination thereof, and any metal oxide used as a charge in the art may be used.

[0079] The imide-based major substituted agent includes, but is not limited to, Poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl]-[(2,2,6,6-tetramethyl-4-piperidyl)imino]-hexamethylene-[(2,2,6,6-tetramethyl-4-piperidyl)imino], 4-Nitro-N-phenylphthalimide, 1,4-Phenylene-bis-maleimide, 4,4'-Bismaleimidodiphenylmethane, or a combination thereof, and any imide-based compound used as a major substituted agent in the art is possible.

[0080] The content of the charging agent included in the biodegradable resin composition may be 0 to 5 wt%, 0.5 wt% to 5 wt%, 0.5 wt% to 4 wt%, or 0.5 wt% to 3 wt% of the total weight of the biodegradable resin composition. If the content of the charging agent is excessively high, the increase in the charging effect obtained compared to the amount of charging agent added may be minimal. If the content of the charging agent is excessively low, the charging effect may be minimal.

[0081] The biodegradable resin composition may comprise, for example, more than 0.5 to less than 2 parts by weight, 0.6 to 1.9 parts by weight, or 0.6 to 1.8 parts by weight of the organic peroxide viscosity modifier based on 100 parts by weight of the biodegradable resin. The biodegradable resin composition may comprise, for example, more than 0.5 to less than 2 wt%, 0.6 to 1.9 wt%, or 0.6 to 1.8 wt% of the organic peroxide viscosity modifier based on the total weight of the biodegradable resin composition. By including the organic peroxide viscosity modifier in such an amount in the biodegradable resin composition, the biodegradability of a biodegradable filter medium obtained from the biodegradable resin composition can be further improved.

[0082] The biodegradable resin composition may, for example, contain 0 to 5 parts by weight, 0.5 to 4 parts by weight, or 0.5 to 3 parts by weight of the metal oxide charging agent based on 100 parts by weight of the biodegradable resin. The biodegradable resin composition may, for example, contain 0 to 5 wt%, 0.5 to 4 wt%, or 0.5 to 3 wt% of the metal oxide charging agent based on the total weight of the biodegradable resin composition. By containing the charging agent in this content range in the biodegradable resin composition, the filtration efficiency of the biodegradable filter medium can be further improved.

[0083] The biodegradable resin composition may include, for example, 0.5 to 2 parts by weight of an organic peroxide viscosity modifier and 0 to 5 parts by weight of the metal oxide charging agent, based on 100 parts by weight of the biodegradable resin. The biodegradable resin composition may include, for example, 0.5 to 2 wt% of an organic peroxide viscosity modifier and 0 to 5 wt% of a metal oxide charging agent, based on the total weight of the biodegradable resin composition. By simultaneously including the organic peroxide viscosity modifier and the metal oxide charging agent in such content ranges in the biodegradable resin composition, the filtration efficiency and biodegradability of the biodegradable filter medium can be further improved.

[0084] The biodegradable resin composition may be solvent-free, for example. The solvent may be, for example, an aqueous solvent such as water or alcohol, and / or an organic solvent such as hexane. The biodegradable resin composition may be maintained in a liquid state by increasing the temperature of the biodegradable resin without a separate solvent. The manufacturing process of the biodegradable resin composition may not involve the intentional addition of a solvent. That is, the biodegradable resin composition may be manufactured using a dry method.

[0085] The additives may further include, for example, a heat stabilizer, a hydrophilicity regulator, an ultraviolet stabilizer, a flame retardant, an inorganic filler, an organic filler, a softener, a plasticizer, a pigment, an antistatic agent, an end capping agent, a metal deactivator, an antioxidant, a heat stabilizer, a lubricant, a tackifier, a plasticizer, a crosslinking agent, a fragrance, an antibacterial agent, a dispersant, a polymerization inhibitor, a flame retardant, an antioxidant, a light stabilizer, a processing aid, a fluorinated anti-dripping agent, an anti-friction agent, an anti-wear agent, a colorant, a release agent, or a combination thereof. The additives are not limited to these, and any additive that can improve the physical properties of the biodegradable filter medium in the art may be used. The content of the additive may be, for example, 0 to 10 wt%, 0 to 7 wt%, 0 to 5 wt%, 0 to 3 wt% or 0 to 1 wt% of the total weight of the biodegradable resin composition.

[0086] The biodegradable resin composition may include, for example, an inorganic filler. The inorganic filler acts as a support or filler that supports the shape of the biodegradable filter medium against external impact, for example as a hard core, thereby improving the impact resistance and / or heat resistance of the biodegradable filter medium including the inorganic filler. The content of the inorganic filler may be, for example, 0 to 5 wt%, 0 to 3 wt%, or 0 to 1 wt% of the total weight of the biodegradable resin composition. If the content of the inorganic filler is too low, the effect obtained by the inorganic filler may be minimal. If the content of the inorganic filler is too high, agglomeration of the inorganic filler may occur, and uniform dispersion of the inorganic filler may be difficult to obtain. The inorganic filler may have a form such as a fiber, plate, or particle. The aspect ratio of the plate-like or fibrous inorganic filler may be, for example, 5 to 100, 5 to 50, 5 to 30, 5 to 20, or 5 to 10. When the inorganic filler has a fibrous form within this range, the bonding between the biodegradable resin and the inorganic filler can be more effectively achieved. The heat resistance and / or impact resistance of the biodegradable filter medium containing such an inorganic filler can be further improved. The inorganic filler may be, for example, talc, glass wool, glass fiber, mica, alumina, wollastonite, clay, mica, kaolinite, montmorillonite, zeolite, graphite, carbon nanotubes, carbon black, zinc oxide, magnesium oxide, titanium oxide, calcium sulfide, boron nitride, calcium carbonate, barium sulfate, aluminum oxide, neodymium oxide, mineral whisker, basalt fiber, wallstonite, or a combination of two or more thereof. The inorganic filler may include, for example, talc, glass wool, mica, etc. The inorganic filler may be, for example, a non-carbonaceous filler.The average particle diameter of the inorganic filler can be 1 μm to 100 μm, 1 μm to 50 μm, 1 μm to 30 μm, or 1 μm to 10 μm. The average particle diameter is, for example, measured using a laser scattering particle size distribution meter (e.g., Horiba LA-920), and is the value of the median particle diameter (D50) when 50% of the small particles are accumulated in volume conversion. Alternatively, the average particle diameter is, for example, the arithmetic mean value of particle diameters of the inorganic filler obtained from a scanning electron microscope (SEM) image of a biodegradable filter medium containing the inorganic filler, calculated manually or by software. The particle diameter of the inorganic filler is, for example, the average value of the maximum and minimum distances between the longitudinal ends.

[0087] The biodegradable resin composition may include, for example, an organic filler. Organic fillers include, for example, sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, sodium octacosate, calcium octacosate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanate, calcium montanate, sodium toluate, sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, sodium cyclohexanecarboxylate, etc. Organic sulfonic acid salts such as carboxylic acid metal salts, sodium p-toluenesulfonate, and sodium sulfoisophthalate, carboxylic acid amides such as stearic acid amide, ethylenebislauric acid amide, palmitic acid amide, hydroxystearic acid amide, erucic acid amide, and trimesic acid tris(t-phthalamide), low-density polyethylene, high-density polyethylene, polypropylene, polyisopropylene, polybutene, poly-4-methylpentene, poly-3-methylbutene-1, polyvinylcycloalkane, polyvinyltrialkylsilane, sodium salts of ethylene-acrylic acid or methacrylic acid copolymers, sodium salts of styrene-maleic anhydride copolymers, and sodium or potassium salts of polymers having carboxyl groups (so-called ionomers), benzylidene sorbitol and its derivatives, phosphoric acid such as NA-11 and NA-71 manufactured by ADEKA Ester metal salts, and 2,2-methylbis(4,6-di-t-butylphenyl)sodium, etc. can be mentioned. For example, ethylenebislauric acid amide, benzyl sorbitol and its derivatives, organic carboxylic acid metal salts, carboxylic acid amides, phosphoric acid ester metal salts such as NA-11 and NA-71 manufactured by ADEKA can be used. Organic fillers can be used alone, for example, or two or more types can be used in combination.The impact resistance and / or heat resistance of the biodegradable filter material can be further improved by including an organic filler in the biodegradable resin composition. The content of the organic filler included in the biodegradable resin composition may be 0 to 5 wt%, 0 to 3 wt%, or 0 to 1 wt% of the total weight of the biodegradable resin composition.

[0088] The biodegradable resin composition may include, for example, a terminal blocker. The terminal blocker may include a carbodiimide compound such as a polycarbodiimide compound or a monocarbodiimide compound. When the compound reacts with some or all of the terminal carboxyl groups of polylactic acid, side reactions such as hydrolysis are blocked, thereby improving the water resistance of a molded article including the biodegradable resin composition. Accordingly, the durability of a molded article including the biodegradable resin composition under a high temperature and high humidity environment may be improved. The polycarbodiimide compound may be, for example, poly(4,4'-diphenylmethanecarbodiimide), poly(4,4'-dicyclohexylmethane carbodiimide), poly(1,3,5-triisopropylbenzene) polycarbodiimide, poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene) polycarbodiimide, or the like. The monocarbodiimide compound may be, for example, N,N'-di-2,6-diisopropylphenylcarbodiimide, etc. The content of the terminal blocker included in the biodegradable resin composition may be 0 to 5 wt%, 0 to 3 wt%, or 0 to 1 wt% of the total weight of the biodegradable resin.

[0089] The biodegradable resin composition may include a stabilizer or colorant to stabilize the molecular weight or color during molding. Examples of stabilizers include phosphorus-based stabilizers, hindered phenol-based stabilizers, ultraviolet absorbers, heat stabilizers, and antistatic agents. Examples of phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphonic acid, and their esters (phosphite compounds, phosphate compounds, phosphonite compounds, phosphonate compounds, etc.), and tertiary phosphines. Examples of stabilizers containing phosphonite compounds as their main components include Sandostab P-EPQ (Clariant) and Irgafos P-EPQ (CIBA SPECIALTY CHEMICALS). As stabilizers with phosphite compounds as their main component, PEP-8 (Asahi Densha), JPP681S (Tohoku Chemical), PEP-24G (Asahi Densha), Alkanox P-24 (Great Lakes), Ultranox P626 (GE Specialty Chemicals), Doverphos S-9432 (Dover Chemical), Irgaofos126, 126 FF (CIBA SPECIALTY CHEMICALS), PEP-36 (Asahi Densha), PEP-45 (Asahi Densha), Doverphos S-9228 (Dover Chemical) can be used. As hindered phenol stabilizers (antioxidants), general compounds that are mixed with conventional resins can be used. The hindered phenol stabilizer may be, for example, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, but is not limited thereto, and any hindered phenol compound used as an oxidation stabilizer of a resin composition in the relevant technical field may be used. The content of the phosphorus stabilizer and the hindered phenol antioxidant in the biodegradable resin composition may be 0 to 5 wt%, 0 to 3 wt%, or 0 to 1 wt% based on the total weight of the biodegradable resin composition.

[0090] The biodegradable resin composition may include a UV absorber. By including the UV absorber, the deterioration of the weather resistance of the molded product due to the influence of rubber components or flame retardants can be suppressed. As the UV absorber, a benzophenone-based UV absorber; a benzotriazole-based UV absorber; a hydroxyphenyltriazine-based UV absorber; a cyclic iminoester-based UV absorber; a cyanoacrylate-based UV absorber, etc. can be used. The content of the UV absorber in the biodegradable resin composition may be 0 to 5 wt%, 0 to 3 wt%, or 0 to 1 wt% of the total weight of the biodegradable resin composition.

[0091] The biodegradable resin composition may include dyes or pigments as colorants to impart various colors to the molded product.

[0092] The biodegradable resin composition may include an antistatic agent to impart antistatic properties to the molded product.

[0093] The biodegradable resin composition may additionally include a thermoplastic resin other than the above, a flow modifier, an antibacterial agent, a dispersant such as liquid paraffin, a photocatalytic foulant, a heat absorbent, and a photochromic agent.

[0094] The step of preparing a biodegradable resin blend by blending a biodegradable resin composition can be performed by, for example, an extruder, a Banburry mixer, a kneader, a continuous kneader, a roll, etc.

[0095] An extruder may be used, particularly, in the step of preparing a biodegradable resin blend. The extruder may include, for example, a first zone including a hopper, a second zone including a header, and one or more intermediate zones disposed therebetween. The temperatures of the first zone, the second zone, and the one or more intermediate zones therebetween may independently be 175 to 200°C or 180 to 195°C. By having the first zone, the second zone, and the intermediate zone having temperatures within these ranges, the biodegradable resin composition can be more effectively blended. If the temperatures of the first zone, the second zone, and the intermediate zone are excessively low, blending of the biodegradable resin composition may be incomplete. If the temperatures of the first zone, the second zone, and the intermediate zone are excessively high, thermal decomposition of the biodegradable resin may occur.

[0096] In an extruder, a temperature may increase from a first region through the intermediate region to the second region. The temperature of the second region may be higher than that of the first region. The temperature difference between the second region and the first region may be 5 to 20° C. or 10 to 20° C. The intermediate region may include, for example, a third region, a fourth region, a fifth region, and a sixth region. For example, the temperature of the first region may be 175 to 185° C. For example, the temperature of the second region may be 190 to 200° C. For example, the temperature of the third region may be 180 to 190° C. For example, the temperature of the fourth region may be 180 to 190° C. For example, the temperature of the fifth region may be 185 to 195° C. For example, the temperature of the sixth region may be 185 to 195° C. Since the first to sixth zones have these temperature ranges, the biodegradable resin blend can be more easily manufactured. The biodegradable resin composition described above can be fed, for example, through a hopper in the first zone, and sequentially passed through the third, fourth, fifth, and sixth zones, and then discharged through a die in the second zone including a header. The biodegradable resin composition is blended while moving, for example, from the third zone to the sixth zone.

[0097] Next, the biodegradable resin blend is heated to prepare a molten biodegradable resin blend.

[0098] Biodegradable fibers can be spun from the molten biodegradable resin blend by melting the biodegradable resin blend to prepare a molten biodegradable resin blend.

[0099] The temperature of the molten biodegradable resin blend can be, for example, from 200 to 300°C, from 200 to 250°C, or from 200 to 230°C. The melt flow rate (MFR) of the molten biodegradable resin blend measured at 230°C according to ASTM D1238 in this temperature range can be, for example, greater than 120 g / 10min to 550 g / 10min, 121 g / 10min to 550 g / 10min, 150 g / 10min to 550 g / 10min, 200 g / 10min to 550 g / 10min, 250 g / 10min to 550 g / 10min, or 300 g / 10min to 500 g / 10min.

[0100] Next, the molten biodegradable resin blend is spun to prepare a biodegradable fiber member.

[0101] The melting and spinning of the biodegradable resin blend can be performed sequentially or simultaneously. For example, the biodegradable resin blend in particle form can be fed into a spinning device, and the biodegradable resin blend can be melted and spun through a nozzle of a die simultaneously. Alternatively, the biodegradable resin blend in particle form can be fed into a spinning device, the biodegradable resin blend can be melted, and then the melted biodegradable resin blend can be spun through a die.

[0102] Conditions for spraying the molten biodegradable resin blend can be controlled by, for example, nozzle temperature, air pressure and air temperature.

[0103] The nozzle temperature for spinning the molten biodegradable resin blend may be, for example, 200 to 250°C, 210 to 240°C, or 220 to 230°C. By having a nozzle temperature in this range, the dimensional stability and / or physical properties of the spun biodegradable resin fibers can be more easily controlled. Accordingly, the resulting biodegradable filter medium can have improved filtration efficiency and biodegradability.

[0104] The air pressure applied to the molten biodegradable resin fibers is, for example, 1 to 10 Nm 3 / min, 2 to 8 Nm 3 / min, 3 to 7 Nm 3 / min or 4 to 5.5 Nm 3 / min. By having an air pressure in this range, the dimensional stability and / or physical properties of the biodegradable resin fibers can be more easily controlled. Therefore, the manufactured biodegradable filter medium can have improved filtration efficiency and biodegradability.

[0105] The air temperature applied to the molten biodegradable resin fibers may be, for example, 205 to 255°C, 215 to 245°C, or 225 to 235°C. By having an air temperature within this range, the dimensional stability and / or physical properties of the radiated biodegradable resin fibers can be more easily controlled. Therefore, the resulting biodegradable filter medium can have improved filtration efficiency and biodegradability.

[0106] The radiated biodegradable resin fibers can form a biodegradable fiber member.

[0107] Referring to FIG. 3, biodegradable resin fibers emitted from a nozzle can be arranged in a web shape on a collector and wound around a winder. Thus, a biodegradable fiber member can be manufactured. The biodegradable fiber member can be, for example, in the form of a nonwoven fabric.

[0108] Next, the step of preparing a rolled biodegradable fiber member by rolling the biodegradable fiber member may be further included.

[0109] The filtration efficiency of the biodegradable filter media produced by additionally rolling the biodegradable fiber member can be further improved. Rolling the biodegradable fiber member can be performed at, for example, 50 to 80°C, 55 to 75°C, or 60 to 70°C. If the rolling temperature is too low, the effect of improving the filtration efficiency may be minimal. If the rolling temperature is too high, defects may occur due to melting of the biodegradable fiber. Rolling can be performed, for example, by a heated roller. The heated roller can be, for example, a calender roller. Rolling can be performed, for example, by calendering. The calendering can be performed, for example, by a pair of calender rolls. The speed at which the biodegradable fiber member is supplied to the calendering rolls can be 10 cm / min to 20 m / min. The temperature of the calendering rolls can be, for example, 50 to 80°C, 55 to 75°C, or 60 to 70°C.

[0110] Next, the step of preparing a charged biodegradable fiber member by electrifying the biodegradable fiber member may be further included.

[0111] The treatment can be performed dry or wet.

[0112] Dry charging is a method of directly charging a biodegradable fiber member without using a liquid, such as a polar solvent. Dry charging can be performed, for example, by electric charging. Dry charging can be performed, for example, by plasma charging or corona charging. Charging can be performed, for example, by electric charging. The voltage applied during dry charging can be, for example, 10 kV or more, 20 kV or more, 30 kV or more, or 40 kV or more. By applying a voltage within this range, a positive charge can be effectively applied to the surface of the biodegradable fiber member.

[0113] Wet charging is a charging process using a liquid, such as a polar solvent. As a wet charging process, for example, a method of charging by applying an external force after applying a polar solvent to a biodegradable fiber member, or simultaneously applying a polar solvent, or a method of charging by applying an external force while the biodegradable fiber member is immersed in a polar solvent filled in a container. The polar solvent can be a liquid with low electrical conductivity, such as water, alcohol, acetone, or water containing ammonia. By using water as a polar solvent, the working environment when charging the biodegradable fiber member is excellent, and ignition can be prevented during the drying stage of the charged biodegradable fiber member. The temperature of the polar solvent used in the wet charging process can be, for example, 40°C or lower or 30°C or lower, but is not limited to these ranges and any temperature that can charge the biodegradable fiber member is possible. The method for applying the polar solvent to the biodegradable fiber member may be, for example, a method for applying the polar solvent in the form of a mist, droplets, or liquid using a spray, shower, nozzle, etc. The method for immersing the biodegradable fiber member in the polar solvent may be, for example, a method for using an impregnation device. The method for applying or immersing the polar solvent to the biodegradable fiber member is not limited to the above-described methods, and any method capable of charging the biodegradable fiber member may be used. The method for applying the force may be, for example, a method for applying ultrasonic waves, vibration, or a method for colliding a solvent flow of a polar solvent. By using a method for colliding a solvent flow of a polar solvent, it is possible to apply a force while simultaneously applying the polar solvent to the biodegradable fiber member. By using an ultrasonic method, it is possible to prevent the formation of open pores and changes in fiber orientation in the biodegradable fiber member during the process of applying the force.The strength and duration of the force applied to the biodegradable fiber member can be appropriately adjusted to increase the charge amount of the biodegradable fiber member.

[0114] The biodegradable fibrous member charged by the wet charging method may be subjected to an additional drying process to remove the polar solvent. Drying of the charged biodegradable fibrous member may be performed by, for example, a can dryer, a heating roller, a hot air dryer, a hot air dryer, an electric furnace, a heat plate, or the like. The drying temperature may be, for example, 120°C or lower, 105°C or lower, or 90°C or lower. Alternatively, without using a drying device, the charged biodegradable fibrous member may be dried naturally as a fiber or nonwoven fabric, or the polar solvent may be removed by applying ultrasonic waves or vibrations to the biodegradable fibrous member.

[0115] The charging process can be performed, for example, by hydrocharging. During hydrocharging, the water pressure applied to one side of the biodegradable fiber member can be, for example, 0.1 bar or more, 0.5 bar or more, 1 bar or more, 2 bar or more, 3 bar or more, 5 bar or more, or 10 bar or more. By applying the water pressure in this range, water can be sufficiently supplied to the inside of the biodegradable fiber member. During hydrocharging, the suction rate applied to the other side of the biodegradable fiber member opposite the one side can be 50% or more, 60% or more, 70% or more, or 80% or more. The suction rate represents, for example, the ratio of the suction motor RPM to the maximum process output value in the suction step for removing water before the drying step after the moisture treatment during hydrocharging. If the suction rate is too low, the charging effect may be poor. Excessively high suction rates may increase the likelihood of defects in the biodegradable fiber member.

[0116] According to another embodiment, a biodegradable filter material comprises a biodegradable fiber member, wherein the biodegradable fiber member comprises a biodegradable resin and an additive, and wherein the additive comprises a viscosity modifier, a charging agent, or a combination thereof.

[0117] The biodegradable fiber member may satisfy, for example, the following mathematical equation 1:

[0118] <Mathematical Formula 1>

[0119] 7 < [A + 1 / 10ХB]

[0120] In the above formula,

[0121] A is the elongation (%) of the biodegradable filter material at 25 ℃, and B is the tensile strength (kgf / cm) of the biodegradable filter material at 25 ℃. 2 )am.

[0122] The biodegradable filter medium may have, for example, a value of [A + 1 / 10ХB] of 8 or more, 9 or more, 10 or more, 15 or more, or 20 or more in mathematical formula 1. By satisfying mathematical formula 1, the dimensional stability and durability of the biodegradable filter medium are improved, and it can be easily formed into various shapes.

[0123] The elongation at break of the biodegradable filter medium, as measured in accordance with ASTM D 638, may be, for example, 4% or more, 10% or more, or 20% or more. The elongation at break of the biodegradable filter medium may be, for example, 200% or less, 100% or less, or 50% or less. The elongation at break of the biodegradable filter medium may be, for example, 4% to 200%, 4% to 100%, 4% to 50%, 10% to 50%, or 20% to 50%. If the elongation at break of the biodegradable filter medium is too low, it may be difficult to form the biodegradable filter medium into other shapes. For example, it may be difficult to apply the biodegradable filter medium to a lamination process with other filter materials. If the elongation at break of the biodegradable filter medium is too high, the dimensional stability and durability of the biodegradable filter medium may be reduced.

[0124] The tensile strength of biodegradable media measured according to ASTM D 638 is, for example, 4.0 kgf / cm 2 Above, 6.0 kgf / cm 2 Above, 8.0 kgf / cm 2 Above, 10.0 kgf / cm 2 or more than 20 kgf / cm 2 It can be ideal. The tensile strength of biodegradable filter media is, for example, 4.0 to 100 kgf / cm. 2 , 6.0 to 80 kgf / cm 2 , 8.0 to 60 kgf / cm 2 , 10 to 50 kgf / cm 2 or 20 to 50 kgf / cm 2 This can be problematic. If the tensile strength of a biodegradable filter medium is excessively low, its dimensional stability and durability may deteriorate. If the tensile strength of a biodegradable filter medium is excessively high, it may be difficult to shape it into other shapes. For example, it may be difficult to apply biodegradable filter medium to processes such as laminating it with other filter materials.

[0125] The melt index, more specifically the melt flow rate (MFR), measured at 230° C. according to ASTM D1238 for the melt of the biodegradable filter material may be, for example, greater than 120 g / 10 min to 550 g / 10 min, 121 g / 10 min to 550 g / 10 min, 150 g / 10 min to 550 g / 10 min, 200 g / 10 min to 550 g / 10 min, 250 g / 10 min to 550 g / 10 min or 300 g / 10 min to 500 g / 10 min. The melt flow rate (MFR) according to ASTM D1238 can be determined, for example, by measuring the weight of the resin discharged through an orifice with an inner diameter of 2.09 mm and a length of 8 mm at 230°C for 10 minutes using a 160 g load. If the melt flow rate is too low, the diameter of the fibers to be spun may increase excessively, which may reduce the filtration efficiency of the biodegradable media at the same thickness. If the melt flow rate is too high, the heat resistance of the fibers to be spun may be reduced, which may cause thermal deformation of the biodegradable resin blend during the melting step and / or the spinning step, making it difficult to manufacture the biodegradable media.

[0126] The biodegradation period of the biodegradable filter medium may be, for example, 80% or less, 75% or less, 70% or less, 60% or less, or 50% or less of the biodegradation period of a biodegradable filter medium composed solely of a biodegradable resin used in the manufacture of the biodegradable filter medium. When the biodegradable filter medium is manufactured from a biodegradable resin composition that additionally includes an additive including a viscosity modifier, a charging agent, or a combination thereof, the biodegradation period may be shortened compared to a biodegradable filter medium manufactured solely from a biodegradable resin without such additive. Accordingly, the recycling efficiency of the biodegradable filter medium may be further improved. The biodegradable filter medium manufactured from a biodegradable resin composition that additionally includes an additive including a viscosity modifier, a charging agent, or a combination thereof includes the additive, and the additive may include the viscosity modifier, the charging agent, or a combination thereof. The biodegradability of the biodegradable filter medium may be measured, for example, according to ISO 14855-2.

[0127] The biodegradable filter medium comprises a biodegradable fibrous member, which may be, for example, a web comprising biodegradable fibers. The biodegradable filter medium may be, for example, in the form of a biodegradable nonwoven fabric. The fiber diameter of the biodegradable fibrous member may be, for example, 1 to 10 μm, 1 to 8 μm, 1 to 6 μm, or 1 to 4 μm. When the biodegradable fibrous member has a fiber diameter within this range, the filtration efficiency and biodegradability of the biodegradable filter medium can be further improved. If the fiber diameter of the biodegradable fibrous member is excessively reduced, the strength of the biodegradable filter medium may be reduced. If the fiber diameter of the biodegradable fibrous member is excessively increased, the filtration efficiency and biodegradability of the biodegradable filter medium may be reduced.

[0128] The unit weight of biodegradable filter media is, for example, 10 to 300 g / m 2 , 20 to 200 g / m 2 , 30 to 100 g / m 2or 30 to 80 g / m 2 This can be done. By having a maximum unit weight within this range, the biodegradable filter media can simultaneously provide enhanced filtration efficiency and biodegradability. If the unit weight of the biodegradable filter media is reduced excessively, the mechanical strength may be excessively reduced, which may cause the biodegradable filter media to break during the subsequent molding process, making it difficult to apply it to subsequent molding processes. If the unit weight of the biodegradable filter media is excessively increased, the energy required during the subsequent molding process may increase excessively, which may reduce the process efficiency during filter manufacturing.

[0129] The average pore size of the biodegradable filter medium may be, for example, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, or 10 to 20 μm. By having an average pore size in this range, the biodegradable filter medium can simultaneously provide enhanced filtration efficiency and biodegradability. If the average pore size of the biodegradable filter medium is excessively reduced, the differential pressure may increase excessively, which may limit its application. If the average pore size of the biodegradable filter medium is excessively increased, the filtration efficiency may decrease excessively, making it difficult to apply it for filter applications.

[0130] The maximum pore size of the biodegradable filter medium can be, for example, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, or 35 μm or less. The biodegradable filter medium can provide both enhanced filtration efficiency and biodegradability by having a maximum pore size in this range. If the maximum pore size of the biodegradable filter medium increases excessively, the filtration efficiency of the biodegradable filter medium may decrease. If the maximum pore size of the biodegradable filter medium decreases excessively, the differential pressure of the biodegradable filter medium may increase excessively. The fiber diameter, average pore size, and maximum pore size included in the biodegradable fibrous member can be calculated automatically by software or manually by manual calculation from, for example, a scanning electron microscope image of the biodegradable fibrous member.

[0131] The filtration efficiency of the biodegradable filter media measured according to EN1822 can be, for example, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 98% or more or 99% or more. The biodegradable filter media having such filtration efficiency can be applied to filters for various purposes. The differential pressure measured according to EN1822 of the biodegradable filter media can be, for example, 10 mmH2O or less, 8 mmH2O or less, 6 mmH2O or less or 5 mmH2O or less. The differential pressure measured according to EN1822 of the biodegradable filter media can be, for example, 0.1 mmH2O or more, 0.5 mmH2O or more, 0.7 mmH2O or more or 1 mmH2O or more. The differential pressure of the biodegradable filter media, measured according to EN1822, can be, for example, 0.1 to 10 mmH2O, 0.5 to 10 mmH2O, 0.5 to 8 mmH2O, 0.5 to 6 mmH2O or 0.5 to 5 mmH2O or less. Since the biodegradable filter media has a differential pressure in this range, it can be applied to various filters by providing both good filtration ability and filtration life. If the differential pressure of the biodegradable filter media is too low, the filtration ability may be insignificant. If the inlet of the biodegradable filter media is too high, the filter life may be excessively shortened.

[0132] The biodegradable filter medium may be, for example, a charged biodegradable filter medium. The charged biodegradable filter medium may include a charging agent. The charged biodegradable filter medium can more effectively filter negatively charged dusts, etc., by being positively charged on the surface and / or inside of the biodegradable filter medium, for example. The filtration efficiency of the charged biodegradable filter medium, measured according to EN1822, may be, for example, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, 98% or more, or 99% or more. The filtration efficiency of the charged biodegradable filter medium may be improved by 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more compared to the filtration efficiency of an uncharged biodegradable filter medium. The charged biodegradable filter medium can be applied to various filters by providing such high filtration efficiency. Biodegradable media are, for example, meltblown media manufactured using a meltblown process. The filtration efficiency of biodegradable media can be further enhanced by the fact that the biodegradable media is meltblown.

[0133] A filter according to another embodiment comprises the biodegradable filter medium described above.

[0134] The filter may be, for example, an air purification filter. The filter may have a single-layer structure or a multi-layer structure. The filter may have a single-layer structure, for example, composed of the biodegradable filter medium described above.

[0135] The filter may have a multilayer structure, for example, including an inner layer and an outer layer, and at least one of the inner layer and the outer layer may include the biodegradable filter medium described above. Both the inner layer and the outer layer may be made of a biodegradable resin. The filter may not include a petroleum-based non-biodegradable resin. The filter may have a multilayer structure, for example, including a filter layer and a support layer. The filter layer may be arranged upstream of the air flow compared to the support layer, and at least one of the filter layer and the support layer may include the biodegradable filter medium described above. The filter may have a multilayer structure, for example, including at least one filter layer arranged between a plurality of support layers. The filter having such a structure can provide excellent dust collection efficiency and durability. In addition, the filter assembly may further include a filter holder that mechanically supports the filter. As a result, the filter assembly can provide excellent dust collection efficiency and mechanical properties at the same time. Therefore, the filter assembly can be used for various purposes.

[0136] Referring to FIG. 3, a filter (1) includes an inner layer (100) and an outer layer (200), the inner layer (100) includes a first filter layer (10) including the above-described biodegradable filter medium, the biodegradable filter medium includes a first biodegradable polymer, the outer layer (200) includes a second support layer (40) disposed on one surface of the inner layer (100) and including a second biodegradable polymer; and a third support layer (50) disposed on the other surface of the inner layer (100) and including a third biodegradable polymer, and the second support layer (40) is disposed upstream of the air flow compared to the first filter layer (10).

[0137] The inner layer (100) includes a first filter layer (10) that provides a filtering function to the filter. The outer layer (200) includes a second support layer (40) and a third support layer (50) that protect both sides of the inner layer (100), respectively.

[0138] The first filter layer (10) is, for example, the biodegradable filter medium described above, and includes the first biodegradable polymer. Alternatively, the first filter layer (10) is, for example, a meltblown nonwoven fabric including the biodegradable filter medium described above. Since the first filter layer (10) includes the meltblown nonwoven fabric, the filter can provide excellent filtration efficiency. The first filter layer (10) can be manufactured by, for example, thermocompression bonding the biodegradable filter medium alone or together with another layer, but is not necessarily limited to this method, and can be manufactured by a known meltblown nonwoven fabric manufacturing method within the scope of using the biodegradable filter medium.

[0139] At least one of the second support layer (40) and the third support layer (50) is, for example, a spunbond nonwoven fabric. The second support layer (40) and the third support layer (50) are, for example, a spunbond nonwoven fabric containing a second biodegradable polymer. By including the spunbond nonwoven fabric in the second support layer (40) and / or the third support layer (50), the inner layer (100) can be protected and the mechanical strength of the filter (1) can be further improved.

[0140] The second support layer (40) and the third support layer (50) can be manufactured by, for example, melt-spinning a third biodegradable polymer to produce a spunbond web and then thermocompression-bonding it alone or together with other layers, but are not necessarily limited to this method and can be manufactured by a known meltblown nonwoven fabric manufacturing method.

[0141] Referring to FIG. 4, a filter (1) includes an inner layer (100) and an outer layer (200), wherein the inner layer (100) includes a first filter layer (10) including the biodegradable filter medium described above; and a first support layer (20) including a second biodegradable polymer, wherein the outer layer (200) includes a second support layer (40) disposed on one surface of the inner layer (100) and including a third biodegradable polymer; and a third support layer (50) disposed on the other surface of the inner layer (100) and including a third biodegradable polymer, wherein the first filter layer (10) is disposed upstream of the air flow compared to the first support layer (20). The biodegradable filter medium includes the first biodegradable polymer.

[0142] The inner layer (100) includes a first filter layer (10) that primarily provides a filtering function to the filter and a first support layer (20) that supports the first filter layer (20). The outer layer (200) includes a second support layer (40) and a third support layer (50) that protect both sides of the inner layer (100), respectively.

[0143] The first filter layer (10) is, for example, the biodegradable filter medium described above, and includes the first biodegradable polymer. Alternatively, the first filter layer (10) is, for example, a meltblown nonwoven fabric including the biodegradable filter medium described above. Since the first filter layer (10) includes the meltblown nonwoven fabric, the filter can provide excellent dust collection efficiency. The first filter layer (10) can be manufactured by, for example, thermocompression bonding the biodegradable filter medium alone or together with another layer, but is not necessarily limited to this method, and can be manufactured by a known meltblown nonwoven fabric manufacturing method within the scope of using the biodegradable filter medium.

[0144] At least one of the second support layer (40) and the third support layer (50) is, for example, a spunbond nonwoven fabric. The first support layer (20) is, for example, a spunbond nonwoven fabric containing a third biodegradable polymer. Since the first support layer (20) includes a spunbond nonwoven fabric containing a second biodegradable polymer, the filter bag (1) can provide excellent mechanical strength. The second support layer (40) and / or the third support layer (50) is, for example, a spunbond nonwoven fabric containing a second biodegradable polymer. Since the second support layer (40) and / or the third support layer (50) includes a spunbond nonwoven fabric, the inner layer (100) can be protected and the mechanical strength of the filter bag (1) can be further improved.

[0145] The first support layer (20) can be manufactured, for example, by melt-spinning a second biodegradable polymer to produce a spunbond web and then thermo-compression-bonding it alone or together with another layer, but is not necessarily limited to this method and can be manufactured using a known spunbond nonwoven fabric manufacturing method. The second support layer (40) and the third support layer (50) can be manufactured, for example, by melt-spinning a third biodegradable polymer to produce a spunbond web and then thermo-compression-bonding it alone or together with another layer, but is not necessarily limited to this method and can be manufactured using a known meltblown nonwoven fabric manufacturing method.

[0146] Referring to FIG. 5, the inner layer (100) may further include a second filter layer (30) that is disposed, for example, on one surface of the first filter layer (10) and includes a fourth biodegradable polymer, as compared to FIG. 4. By the inner layer (100) additionally including the second filter layer (30), the dust collection efficiency of the filter (1) may be further improved. The second filter layer (30) may include, for example, the biodegradable filter medium described above. The biodegradable polymers included in the first filter layer (10) and the second filter layer (30) may be the same or different.

[0147] The elongation at break of the second biodegradable polymer included in the first support layer (20) may be greater than the elongation at break of the first biodegradable polymer included in the first filter layer (10). In addition, the elongation at break of the second biodegradable polymer included in the first support layer (20) may be greater than the elongation at break of the third biodegradable polymer included in the second support layer (40) and the third support layer (50). The durability of the filter may be improved by the first support layer (20) including the second biodegradable polymer having an improved elongation at break.

[0148] The first biodegradable polymer may include, for example, polylactic acid. For specific details regarding polylactic acid, refer to the biodegradable resin composition section described above. The second biodegradable polymer and the third biodegradable polymer may be selected from, for example, the biodegradable polymers included in the biodegradable filter medium. The first biodegradable polymer, the second biodegradable polymer, and the third biodegradable polymer may be the same or different. The fourth biodegradable polymer may include, for example, polybutylene succinate, polycaprolactone, or a combination thereof. For more specific details regarding polybutylene succinate and polycaprolactone, refer to the biodegradable resin section described above.

[0149] According to another embodiment, a home appliance may include the filter described above. The home appliance may include, for example, an air purifying filter.

[0150] Home appliances can provide superior filtration by incorporating the aforementioned filters. These include, but are not limited to, vacuum cleaners and air purifiers, and any home appliance that includes the aforementioned filters can be used.

[0151] In addition to home appliances, industrial, industrial, or military products may also include the aforementioned filters. Industrial products may include, for example, large trucks. Industrial products may include, for example, large plants such as semiconductor factories. Military products may include, for example, military vehicles.

[0152] The present invention is further described in detail through the following examples and comparative examples. However, these examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention.

[0153] (Manufacture of biodegradable filter media)

[0154] Examples 1 to 11 and Comparative Examples 1 to 4

[0155] Biodegradable resin compositions of Examples 1 to 11 and Comparative Examples 1 to 4 having the compositions shown in Table 1 below were prepared by mixing 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane as a viscosity control agent and / or 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane as a charging agent with respect to 100 parts by weight of polylactic acid homopolymer (PLLA, poly-L-lactic acid, NatureWorks 4030D) as a biodegradable resin. The biodegradable resin compositions did not contain a separate solvent. The biodegradable resin compositions were fed into an extruder and extruded to prepare biodegradable resin blends.

[0156] The extruder included a first zone including a hopper, a second zone including a head, and third zones, fourth zones, fifth zones, and sixth zones sequentially arranged from the first zone to the second zone between the first zone and the second zone.

[0157] The temperature of the first zone was 180°C, the temperatures of the third and fourth zones were 185°C, the temperatures of the fifth and sixth zones were 190°C, and the temperature of the second zone was 195°C.

[0158] The deeding weight was 12 kg / hr, the screw speed was 600 rpm, and the die pressure was 36 bar. The die was incorporated into the head.

[0159] A biodegradable fiber member was manufactured by melting a biodegradable resin blend and spinning it using a meltblown method. The biodegradable fiber member had a nonwoven fabric form. The biodegradable fiber member corresponds to a biodegradable filter medium.

[0160] In the melt blown process, the nozzle temperature is 220-230 ℃, and the air pressure is 4 to 5.5 Nm. 3 / min. and air temperature was 225 to 235 ℃.

[0161] The biodegradable fiber members manufactured in Examples 5 to 10 were subjected to an electric charging process to manufacture charged biodegradable fiber members. The electric charging process was performed by corona charging.

[0162] The biodegradable fiber member manufactured in Example 11 was manufactured by adding a hydrocharging process.

[0163] The hydrocharging process was performed by supplying distilled water at a water pressure of 2 bar on one side of the biodegradable fiber member and suctioning the opposite side at a suction rate of 80%, followed by drying.

[0164] The biodegradable fiber members manufactured in Examples 10 and 11 were manufactured by adding a calendering process of passing the biodegradable fiber members between a pair of calendering rolls at 70°C.

[0165] Evaluation Example 1: Melt Flow Measurement

[0166] Melt flow was measured for the biodegradable resin blends prepared in Examples 1 to 11 and Comparative Examples 1 to 4.

[0167] Melt flow rate was measured at 230°C according to ASTM D1238 using a melt flow meter (Dynisco Melt Flow Indexer, LMI 5000 Series, load 2160 g).

[0168] Melt flow rate (MFR, g / 10 min) is the weight of a resin extruded at a constant temperature and a specified force for 10 minutes. The measurement results are shown in Table 1 below.

[0169] Evaluation Example 2: Filtration Efficiency Measurement

[0170] The filtration efficiency was measured for the nonwoven biodegradable filter media manufactured in Examples 1 to 11 and Comparative Examples 1 to 2.

[0171] Filtration efficiency was measured according to EN1822 using a filter tester (TSI Corporation, model 8130A, flow rate 32 L / min, NaCl 0.3 ㎛ particles). Filtration efficiency was measured using a 100 cm nonwoven fabric. 2 This is the particle removal rate when a fluid containing particles of a certain size is passed through an area at a certain speed. The measurement results are shown in Table 1 below.

[0172] Viscosity modifier content [wt%] Melt flow (MFR) [g / 10min] Charger content [wt%] Calculating temperature [℃] Charging conditions Filtration efficiency [%] Comparative example 10700--8.7 Comparative example 20.51200--14.6 Example 10.72050--16.0 Example 20.82500--17.2 Example 31.04500--23.7 Example 41.55300--16.9 Comparative example 32.06000--Non-spinnable Comparative example 43.07000--Non-spinnable Example 51.04500-Electric charging 68 Example 61.04500.5-Electric charging 79 Example 71.04501.0-Electric Charging 89 Example 81.04502.0-Electric Charging 86 Example 91.04503.0-Electric Charging 89 Example 101.04501.070-Electric Charging 92 Example 111.04501.070-Electric Charging 95

[0173] As shown in Table 1, the biodegradable filter media manufactured in Examples 1 to 4 had improved melt flowability and filtration efficiency compared to the biodegradable filter media manufactured in Comparative Examples 1 to 2.

[0174] In Comparative Examples 1 and 2, the melt flow of the biodegradable resin blend was lower than in Examples 1 to 4, and thus the spinning of fine biodegradable fibers was not performed smoothly. Therefore, the filtration efficiency of the biodegradable filter media manufactured in Comparative Examples 1 and 2 was lowered.

[0175] In Comparative Examples 3 to 4, the melt flow of the biodegradable resin blend was improved compared to Examples 1 to 4, but thermal decomposition occurred. Therefore, defects occurred during the spinning process from the molten resin blend, making it impossible to manufacture a biodegradable fiber member.

[0176] The biodegradable filter media manufactured in Examples 5 to 11 had further improved filtration efficiency by adding a charging process.

[0177] The biodegradable filter media manufactured in Examples 6 to 9 had improved filtration efficiency compared to Example 5 by additionally including a large electrolyte.

[0178] The biodegradable filter media prepared in Examples 10 to 11 had further improved filtration efficiency by adding a calendaring process.

[0179] Evaluation Example 3: Biodegradability Evaluation

[0180] The biodegradability of the biodegradable filter media manufactured in Examples 2 to 3 and Comparative Example 1 was evaluated.

[0181] Biodegradability was measured according to ISO 14855-2. The time required to reach 80% biodegradability was measured and is shown in Table 2 below.

[0182] Melt flow rate (MFR) [g / 10 min] Biodegradation period [days] Comparative example 17045 Example 225028 Example 345020

[0183] As shown in Table 2, the biodegradation period of the biodegradable filter media of Examples 2 to 3 was reduced by 80% or less compared to the biodegradation period of the biodegradable filter media of Comparative Example 1.

[0184] The biodegradability of the biodegradable filter media of Examples 2 and 3 was significantly improved compared to the biodegradable filter media of Comparative Example 1.

[0185] Evaluation Example 4: Measurement of fiber diameter, average pore size, maximum pore size, and unit weight.

[0186] The cross-sections of the biodegradable filter media manufactured in Examples 1 to 4 were imaged using a scanning electron microscope, and the biodegradable average fiber diameter, average pore size, and maximum pore size were calculated using image analysis software. The calculation results are shown in Table 3 below. The average fiber diameter is the arithmetic mean of the diameters of the fibers measured in the cross-section images of the biodegradable filter media. The average pore size is the arithmetic mean of the diameters of the pores defined by the fibers measured in the cross-section images of the biodegradable filter media. The maximum pore size is the maximum value among the pore sizes used in the calculation of the average pore size.

[0187] The unit weight was derived by measuring the area and weight of the biodegradable filter media manufactured in Examples 1 to 4. The unit weight is shown in Table 3 below.

[0188] Average fiber diameter [㎛]Average pore size [㎛]Maximum pore size [㎛]Unit weight [g / m 2 ]Example 14.75 ± 0.92 10.8 ± 0.42 6.8 ± 2.760Example 24.32 ± 0.63 11.8 ± 0.43 1.1 ± 1.960Example 32.53 ± 0.65 14.9 ± 0.13 6.0 ± 0.360Example 42.93 ± 0.75 12.3 ± 0.32 8.1 ± 1.360

[0189] As shown in Table 3, the biodegradable filter media manufactured in Examples 1 to 4 exhibited an average fiber diameter of 2 to 5 μm, an average pore size of 10 to 20 μm, and a maximum pore size of 40 μm or less.

[0190] [Explanation of symbols]

[0191] 1 filter 10 first filter layer

[0192] 20 1st support layer 30 2nd filter layer

[0193] 40 2nd support layer 50 3rd support layer

[0194] 100 inner layer 200 outer layer

[0195] According to one aspect, a biodegradable filter medium having improved properties can be manufactured by controlling the melt flowability of a molten biodegradable resin blend.

[0196] The filtration efficiency and biodegradability of the biodegradable filter medium manufactured in this way can be improved.

Claims

1. A step of preparing a biodegradable resin blend by blending a biodegradable resin composition; A step of preparing a molten biodegradable resin blend by heating the biodegradable resin blend; and A step of preparing a biodegradable fiber member by spinning the above-mentioned molten biodegradable resin blend, The above biodegradable resin composition comprises a biodegradable resin and an additive, wherein the additive comprises a viscosity modifier, a charging agent or a combination thereof, A method for manufacturing a biodegradable filter material, wherein the melt flow rate (MFR) of the above-mentioned melted biodegradable resin blend measured at 230° C. according to ASTM D1238 is greater than 120 g / 10 min to 550 g / 10 min.

2. A method for manufacturing a biodegradable filter medium according to claim 1, wherein the biodegradable resin comprises polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polyhydroxyalkanoates (PHA), polyhydroxybutyrate (PBH), cellulose or a combination thereof.

3. In the first paragraph, the biodegradable resin composition contains polylactic acid, The above biodegradable resin composition is free of petroleum-based non-biodegradable resin, A method for manufacturing a biodegradable filter material, wherein the polylactic acid content is 97 wt% or more based on the total weight of the biodegradable resin composition.

4. In the first paragraph, the viscosity modifier comprises an organic peroxide-based viscosity modifier, a vinyl-based viscosity modifier, an acrylic-based viscosity modifier, or a combination thereof. The above organic peroxide viscosity modifier is 2.5-dimethyl-2,5-di(tert-butylperoxy)hexane, ditert-butyl peroxide, ditert-amyl peroxide, tert-butyl cumyl peroxide, di(tert-butylperoxy-isopropyl)-benzene, dicumyl peroxide, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, 3,3,5,7,7-pentamethyl-1,2,4-trioxepane or a combination thereof, The above vinyl-based viscosity modifier includes poly(vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate), fluoroethylene vinyl ether, 2-butenedioic acid (2Z)-, 1-(1-methylethyl) ester, N,N'-bis(2,2,6,6,-tetramethylpiperidin-4-yl)-1,3-dicarboxamide, or a combination thereof. The above acrylic viscosity modifier includes methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, butyl methacrylate or a combination thereof.

5. In the first paragraph, the charging agent includes a metal oxide charging agent, an imide charging agent, or a combination thereof, The above metal oxide premise is TiO 2 , SiO 2 , ZnO, SnO 2 A method for manufacturing a biodegradable filter medium, comprising a combination thereof. A method for producing a biodegradable filter medium, wherein the above imide-based premise comprises Poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-s-triazine-2,4-diyl]-[(2,2,6,6-tetramethyl-4-piperidyl)imino]-hexamethylene-[(2,2,6,6-tetramethyl-4-piperidyl)imino], 4-Nitro-N-phenylphthalimide, 1,4-Phenylene-bis-maleimide, 4,4'-Bismaleimidodiphenylmethane or a combination thereof.

6. In the first paragraph, the biodegradable resin composition contains 0.5 to 2 parts by weight of the organic peroxide viscosity modifier per 100 parts by weight of the biodegradable resin, or The biodegradable resin composition comprises 0 to 5 parts by weight of the metal oxide electrostatic agent per 100 parts by weight of the biodegradable resin, or The biodegradable resin composition comprises 0.5 to 2 parts by weight of the organic peroxide viscosity modifier and 0 to 5 parts by weight of the metal oxide charging agent, based on 100 parts by weight of the biodegradable resin. A method for producing a biodegradable filter medium, wherein the biodegradable resin composition is free of a solvent.

7. In the first paragraph, the step of preparing the biodegradable resin blend is performed by an extruder, The extruder comprises a first region comprising a hopper, a second region comprising a header, and at least one intermediate region disposed therebetween, The temperatures of the first region, the second region and at least one intermediate region therebetween are independently 175 to 200° C., A method for manufacturing a biodegradable filter medium, wherein the temperature increases from the first region through the intermediate region to the second region.

8. In the first paragraph, a step of preparing a rolled biodegradable fiber member by rolling the biodegradable fiber member is further included. The above rolling is performed at 55 to 75° C., and further includes a step of electrifying the biodegradable fiber member to prepare an electrified biodegradable fiber member. The above charging process is performed by electric charging or hydro charging, The voltage applied during the above electric charging is 10 kV or more, A method for manufacturing a biodegradable filter medium, wherein the applied water pressure during the hydrocharging is 1 bar or higher and the suction rate is 50% or higher.

9. Contains biodegradable fibers; The above biodegradable fiber member comprises a biodegradable resin and an additive, A biodegradable filter medium comprising the above additives, a viscosity modifier, a charging agent or a combination thereof.

10. A biodegradable filter medium in accordance with claim 9, wherein the melt flow rate (MFR) of the biodegradable filter medium measured at 230° C. according to ASTM D1238 is more than 120 g / 10 min to 550 g / 10 min.

11. A biodegradable filter medium in accordance with claim 9, wherein the biodegradation period of the biodegradable filter medium is 80% or less of the biodegradation period of a biodegradable filter medium composed solely of the biodegradable resin.

12. In the 9th paragraph, the fiber diameter of the biodegradable fiber member is 1 to 10 ㎛, The unit weight of the above biodegradable filter material is 10 to 300 g / m 2 , the average pore size is 10 to 20 ㎛, and the maximum pore size is 40 ㎛ or less. The filtration efficiency of the above biodegradable filter medium measured according to EN1822 is 50% or more and the differential pressure is 5 mmH 2 O or less, biodegradable filter media.

13. A biodegradable filter medium according to claim 9, wherein the biodegradable filter medium is a charged biodegradable filter medium, and the filtration efficiency of the charged biodegradable filter medium measured according to EN1822 is 75% or more.

14. An air purifying filter comprising a biodegradable filter medium according to any one of claims 12 to 13.

15. Home appliances containing air purifying filters according to Article 14.

Images