KR20210035708A - Composite Hepa Filter Based on Fluoro Polymer Membrane Filter - Google Patents

Abstract

The present invention relates to a high-performance HEPA filter based on a fluoropolymer membrane. More specifically, as a filter installed in a semiconductor factory, a display device manufacturing factory, or a clean room to remove contaminants that may be generated in a semiconductor or LCD manufacturing process or introduced from the outside, the present invention relates to a composite filter in which a fluoropolymer membrane filter and/or a fibrous first filter and a second filter having an average diameter smaller than synthetic fibers of the first filter are combined. Further, in a heterogeneous composite filter comprising a fluoropolymer HEPA filter, a melt-blown HEPA filter, a first filter layer, and a second filter layer, the present invention relates to a heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter, characterized in that the average diameter of the synthetic fibers included in the first HEPA filter layer is larger than the average diameter of synthetic fibers included in the second HEPA filter layer, relates to a HEPA filter for a semiconductor clean room in which a non-woven filter layer is additionally combined between the porous fluoropolymer membrane filter and/or the fibrous first filter and the second filter, and relates to a heterogeneous composite filter with a multi-layered structure that extends the replacement period of the HEPA filter through the improvement of the collection amount.

Description

Composite Hepa Filter Based on Fluoro Polymer Membrane Filter}

The present invention relates to a fluororesin filter-based high-performance north combined HEPA filter. More specifically, the present invention is a filter that is installed in a semiconductor factory, a display device manufacturing factory, or a clean room to selectively remove fluorine-based contaminants that may be generated in a semiconductor or LCD manufacturing process or introduced from the outside. And/or a first melt blown filter and a second melt blown filter having an average diameter smaller than that of the fibers of the first melt blown filter are combined into one composite filter.

In addition, the present invention is a heterogeneous composite filter comprising a fluororesin HEPA filter, a melt blown HEPA filter, a first filter layer and a second filter layer, wherein the average diameter of the synthetic fibers contained in the first HEPA filter layer It relates to a heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter, characterized in that it is larger than the average diameter of the impregnated fibers contained in the second HEPA filter layer.

More specifically, the present invention relates to a HEPA filter for a semiconductor clean room in which a filter made of a porous fluororesin membrane and/or a filter layer for collecting filtrates is additionally incorporated between a fibrous first filter and a second filter. The present invention relates to a multi-layered heterogeneous material composite filter that extends the replacement period of the HEPA filter through improvement.

In accordance with the advanced industrial environment, the frequency of human inhalation or exposure to contaminated air is increasing very high, and safety management is being emphasized not only for health reasons, but also to reduce the defect rate of products due to air pollution in industrial sites. Actually.

Accordingly, in industrial sites, a clean air environment is required to reduce the defect rate of products, and a clean room is installed by investing an enormous cost, and a high-functional HEPA filter is installed in various ways in such a clean room.

The airflow method of a clean room is generally divided into three types: vertical laminar flow, horizontal laminar flow, and non-laminar flow. In the vertical laminar flow, more than 80% of the ceiling is equipped with a high-functional filter to draw airflow downward. It is suitable for facilities requiring cleanliness class 10 to 1,000 because the ceiling air circulated to the floor and circulated to the ceiling is ventilated to the shortest distance.

The horizontal laminar flow method is a method that forms laminar flow by installing a high-functional filter on one side of the wall to take it out, and ventilates it to the opposite side to purify it. It is a method suitable for facilities requiring cleanliness class of 100 to 10,000.

In the non-laminar flow method, a high-functional filter is installed on a part of the ceiling, and the air is circulated through the wall on the floor as much as possible, and it is possible to install a filter unit at the outlet of the air conditioning duct. This is a suitable method for the required facility.

Cleanrooms installed in various ways as described above have strict class standards at the site, so they block residual dust in the air supplied from outside to less than 0.3㎛ to maintain cleanliness, lower the defect rate of products, and maintain positive pressure to It requires a large amount of air supply due to the nature of the clean room that blocks air inflow from the air.

In the case of glass fibers that have been used to manufacture HEPA filters so far, since they have high initial static pressure and are composed of short fibers, they absorb moisture and may be damaged by wind pressure. In addition, the chemical resistance is weak, so it cannot be used in an environment where strong acids such as hydrofluoric acid are used, and the tensile strength is weak, so the defect rate is high, and it is fragile and cannot be incinerated.

However, in the case of a melt blown microfiber filter (Melt Blown fiber filter, MB filter) manufactured by a melt spraying method that can be used as an alternative material for glass fiber, it is also difficult to lower the efficiency in order to maintain the air volume due to high initial static pressure. Due to this, there is a problem that the maintenance cost and management cost are greatly increased.

The melt blown (MB) filter, which is currently widely used, is a three-dimensional fiber structure filter manufactured by melt-spinning polypropylene resin or polyethylene or polyester resin with microfiber as long as it is harmless to the human body and has excellent heat resistance. Due to its excellent strength, the amount of impurities collected increases, thereby increasing the efficiency of use of the HEPA filter.

Polypropylene and polyester are mechanically and chemically very stable materials, so secondary contamination by filter decomposition materials does not occur. In addition, since the thickness and length of the fibers forming the melt blown filter can be uniformly adjusted, filtration precision can be increased, and filtration precision can be maintained despite changes in wind pressure.

The HEPA (High Efficiency Particulate Arrestor) filter is a high-performance filter that removes fine particles from the air, and was developed by the US Atomic Energy Commission to remove radioactive substances. The HEPA filter adsorbs particles larger than or equal to 0.3 μm (micrometer), and is divided into H10 to H14 stages.

Of these grades, the H12 grade should be able to filter 99.5% and the H13 grade (medical) 99.95% to capture impurities. The highest H14 grade should be capable of adsorbing and removing 99.995%.

Through the high-performance HEPA H12 filter and the closed filtration system of 4 or more stages, it is possible to adsorb more than 99.95% of harmful particles of 0.05μm smaller than 0.3μm that the HEPA filter can remove. Fine dust, bacteria, and house dust mites that cause allergies and asthma, and even some viruses under 100 nanometers can be filtered if they are in a droplet or aggregated state.

However, since the HEPA filter is difficult to clean due to its characteristics, since the filtrate is accumulated in the HEPA filter, there is a disadvantage in that product performance is deteriorated due to an increase in filtration pressure when the filter is used for a long period of time. Therefore, there is an urgent need to develop a new technology to extend the replacement cycle of the HEPA filter by increasing the collection capacity of the HEPA filter and extending its life.

The meltblown nonwoven fabric spins polymers that can form thermoplastic fibers through hundreds of small spinnerettes, and the polymer extruded from the spinning nozzle is super fined by hot air sprayed at high speed from both sides of the spinneret in the melted state. It is a self-bonding nonwoven fabric in which ultrafine fibers are randomly stacked on a collection body.

This melt blown nonwoven fabric exhibits a performance corresponding to the level of MERV 7 to 16 of the American air filter standard ANSI/ASHRAE 522 (1999), and the higher the MERV value, the better the filter efficiency and means a higher grade filter.

Melt-blown nonwoven fabric has low shape stability after bending due to its flexible characteristics, and does not maintain the shape of the bending process after bending, and returns to its original shape.Therefore, the contact ability between the air and the filter decreases and the filter efficiency decreases, and the pressure loss increases. Occurs. Therefore, the ability to maintain the shape of the filter is indispensable, especially in a cabin filter for automobiles or a high-efficiency medium filter in which a large amount of air flows into a small filter area.

The melt blown (MB) filter, which is used as the main material of the HEPA filter, filters out harmful dust and dust as air flow passes through three-dimensional pores in the range of 1 to 10 microns. The filter media (midia) in the flow in) part is clogged, resulting in a problem that the differential pressure is increased on the filter surface.

It is mainly melt blown nonwoven fabric used as a HEPA filter in the heterogeneous material composite filter of the present invention. Melt blown nonwoven fabric is a nonwoven fabric that is randomly collected by spinning a molten resin into ultrafine fibers having a diameter of about 1 micrometer using compressed air, and it is sometimes produced by employing composite spinning, split spinning, and electrospinning methods.

Melt blown filters manufactured by single component spinning at DuPont or Hyosung in Korea are made of 0.3 denier to 0.2 denier microfiber. A melt blown filter made of 0.0001 denier grade ultra-fine fiber manufactured by Toray in Japan by a multi-component spinning method may be used as a HEPA filter layer of the composite filter of the present invention. These melt blown nanofiber nonwoven fabrics are produced with filters that exhibit selective permeability at the membrane level.

In the present invention, the fiber diameter of the melt blown filter forming the two layers of the HEPA filter layers is different to maintain the filtration capacity of HEPA 13 or higher, while the spun bonding filter is combined between the HEPA filter layers to collect the filtrate while collecting the entire composite filter. The mechanical strength of the HEPA filter was reinforced to prevent physical distortion of the HEPA filter even under considerable wind pressure. By adding a fluorine membrane filter made of a fluorine resin to the composite HEPA filter, the ability to capture fluorine-containing substances such as hydrogen fluoride or sodium fluoride (NaF) has been greatly increased.

The fluorine resin forming the fluorine filter layer used in the present invention refers to a synthetic resin material having a fluorine atom bonded to carbon in a molecule, but in a narrow sense, tetrafluoroethylene (TFE) or an analog thereof, or It means a polymer or copolymer of vinyl monomers.

Typical commercially available fluorine-based polymers currently commercially available are polytetrafluoroentylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and ethylene-tetra. Fluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer ( ECTFE), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer (THV), and polyvinyl fluoride (PVF).

Among these, fully fluorinated crystalline resins are PTFE, PFA, and FEP, and partially fluorinated crystalline resins are ETFE, PVDF, PVF, and PCTFE. Partially fluorinated amorphous resins include LUMIFLON, amorphous elastomers include FKM and AFLAS, fully fluorinated amorphous resins include CYTOP and TEFLON AF, and fully fluorinated amorphous elastomers include KALREA and ZALAK.

The most representative PTFE of fluorine resin is a completely fluorine-type crystalline resin, which has a very high melt viscosity and hardly flows even when heated above the melting point, so injection molding or extrusion molding like general plastics is impossible, and melt blown processing is difficult. Therefore, the fluororesin is produced as a membrane filter through a stretching process or through a special process.

TEMISH® NTF9000 Series, a fluororesin porous film for air filters sold by Nito Corporation of Japan, is ULPA (Ultra Low Penetration Air) grade, HEPA (High Efficiency Particulate Air) grade, and MEDIUM grade that cover and reinforce a PTFE porous membrane with spun-bonded nonwoven fabric. And, since glass fiber is not used, there is no possibility of dust generated from the fabric.

The PTFE porous membrane filter is a high-performance air filter that combines a PTFE porous membrane with excellent dust-collecting properties and a spun-bonded nonwoven fabric selected for high-performance air filtration. As the integration degree and LCD screens increase in the semiconductor industry, a cleaner environment is required, and therefore, a high-performance air filter is required. Since the PTFE porous membrane has dust resistance (vibration resistance), the PTFE porous membrane is used in ULPA (Ultra Low Penetration Air) grade, HEPA (High Efficiency Particulate Air) grade and MEDIUM grade.

EPTFE (expanded polytetrafluoroethylene) membrane, commonly known as Gore-Tex membrane, is a material made of fluorine resin, and consists of more than 9 billion microscopic pores per square inch, so the size of one pore is more than 20,000 times smaller than that of water droplets and water vapor molecules. It is more than 700 times larger than that, and has a filtration function. The ePTFE membrane is used as a filter in various industries such as power generation facilities, home appliances, semiconductor cleaning facilities, and automobiles, and its use is expanding in hydrogen fuel cells, artificial organs, and artificial blood vessels.

Korean Patent No. 10-0731791 discloses a method of manufacturing a filter using a composite spinning melt blown nonwoven fabric and a filter formed therefrom. The filter manufacturing method of this prior art is (S1) a two-component composite spinning meltblown nonwoven fabric composed of two-component composite spinning fibers of a first thermoplastic polymer having a predetermined melting point and a second thermoplastic polymer having a lower melting point than the first thermoplastic polymer. Preparing a; (S2) laminating the two-component composite-spun melt-blown nonwoven fabric on one or both sides of a one-component melt-blown nonwoven fabric made of a third thermoplastic polymer having a melting point higher than that of the second thermoplastic polymer; And (S3) applying heat to the laminated nonwoven fabric at a temperature capable of melting only the second thermoplastic polymer to thermally bond the two-component composite spinning meltblown nonwoven fabric and the one-component meltblown nonwoven fabric to each other. In International Patent PCT/US2000/02458 filed by 3M of the United States of America, the present invention provides a novel fluorochemical oligomer, and a polymer composition comprising a fluorochemical oligomer compound and a thermoplastic polymer or a thermosetting polymer. The polymeric composition is useful for making molded articles such as fibers and films with desirable oil and water repellency properties. Meanwhile, the Donaldson Company of the United States, through international patent application PCT/US2005/039971, provides a thermally bonded sheet that combines high strength and excellent filtration properties, a filter medium, or a filter containing a shaped or formed medium. Includes. A composite filter is disclosed in which a significant proportion of organic or inorganic glass fibers, bicomponent thermoplastic binder fibers, and optionally resin binders, secondary fibers or other filtration material are bonded in the formed layer. The use of bicomponent fibers significantly reduces or prevents film formation from the binder resin and also eliminates the lack of uniformity within the medium or element due to movement of the resin to a specific location of the medium layer, without or with a separate resin binder. It makes it possible to form the media layer or filter element with a positive resin binder. The use of bicomponent fibers allows for reduced compression, improves solidity, increases tensile strength, and facilitates the use of media fibers such as glass fibers and other fine fiber materials added to the media layer or filter element. Improve. The bicomponent fibers also provide improved fairness during downstream processes such as furnish formation, sheet or layer formation and thickness adjustment, drying, cutting, and filter element formation. These binary components combine in varying proportions to form high-strength materials with significant filtration capacity, permeability and filtration life. On February 7, 2019, through Korean Patent Application Publication No. 10-2019-0011838, the United States of America EMD Millipore Corporation formed an inner layer of a coarse porous polymer nonwoven fabric positioned between filter mats containing first and second polymer fibers. A fluid filtration device comprising a composite filter medium having. The diameters of the fibers in the first and second filter mats are different, each filter mat has a different pore size rating, and the first and second polymer fibers in the filter mats may be electrospun nanofibers. In addition, the inner layer has a coarse pore size compared to the first or second filter mat, and the resulting composite medium increases dust compared to the filter layer directly stacked on each other without the presence of a coarse inner layer therebetween. We have disclosed a technique that represents the ability to capture. Meanwhile, Japan's Asahi Kasei Sengi Co., Ltd., through international patent application PCT/JP2007/051091, is a laminated nonwoven fabric integrated by thermocompression, and has at least one (a) layer: a long fiber nonwoven fabric layer made of a thermoplastic resin. ; (b) layer: has at least one ultrafine fiber nonwoven fabric layer made of thermoplastic resin of the same series as the (a) layer; (c) layer: has at least one composite long fiber nonwoven fabric layer made of thermoplastic resin; (1 ) the melting point difference between the fibers constituting the nonwoven fabric of the layer (a) and the fibers constituting the nonwoven fabric of the layer (b) is 30°C or less; (2) The composite filaments made of the thermoplastic resin constituting the nonwoven fabric of the layer (c) contain a low melting point component, and the melting point of the low melting point component is 40 to that of the fibers constituting the nonwoven fabric of the layer (a). A heat-adhesive laminated nonwoven fabric characterized by being low at 150°C has been disclosed.

Accordingly, the present invention is to solve the problems of the prior art as described above, and the collection capacity is increased, so that the replacement cycle of the HEPA filter is lengthened, it is resistant to moisture, and the service life is maintained while maintaining the gas filtration efficiency of the existing HEPA filter. It aims to provide a long fluororesin-based high-performance HEPA filter.

The present invention relates to a HEPA filter in which a fluororesin membrane layer is inserted into a melt blown fibrous filter layer according to the prior art for removing particles or gases generated in a semiconductor or display manufacturing process.

In addition, the present invention combines two or more HEPA filters having different diameters of the fibers of the melt blown filter forming the HEPA filter, and arranges a spun bonding filter between the HEPA filters to increase the filtering material collection capacity. The purpose of this is to extend the replacement period of the HEPA filter and provide a high-performance filter in which a heterogeneous HEPA filter capable of collecting even fluorine-based dust and contaminants by adding a fluorine-based HEPA filter layer.

The heterogeneous material composite HEPA filter according to the present invention includes a first HEPA filter layer and a second HEPA filter layer each containing synthetic fibers, wherein the average diameter of the synthetic fibers included in the first layer is in the second layer. It is larger than the average diameter of the included fiber, and when the treatment capacity is 32m ³ /min, the differential pressure may be less than 5.5mmaq, and the filtration efficiency may be 99.98% or more.

Synthetic fibers included in any one of the first and second HEPA filter layers may be manufactured by melt blowing. A spun-bonding nonwoven filter layer may be further included between the first HEPA filter layer and the second HEPA filter layer.

The average fiber diameter of the melt blown fibers included in the first layer may be 1.0 μm to 10 μm. The average fiber diameter of the melt blown fibers included in the second layer may be 0.1 μm to 1.0 μm.

Any one of the first and second filter layers may be made of one or more materials selected from the group consisting of polyolefin, polyester, polyamide, and polyphenylene sulfide. Preferably, the synthetic fibers may be made from polypropylene and polyethylene terephthalate, respectively.

In addition, the first filter layer and the second filter layer, or the first filter layer, the nonwoven filter layer, and the second filter layer may be laminated by an ultrasonic lamination method.

In this way, a spun-bonded nonwoven fabric layer was laminated between the first HEPA filter layer and the second HEPA filter having different diameters of the melt blown fibers, and a fluororesin membrane filter layer was added before and after the second HEPA filter layer.

The heterogeneous material composite HEPA filter according to the present invention was manufactured using either the first HEPA filter or the second HEPA filter using a fluororesin HEPA filter made of fluorine fibers or a fluororesin membrane filter layer.

The heterogeneous material composite HEPA filter according to the present invention can save energy due to low pressure loss, is easy to install since there is no risk of damage to the filter, and is resistant to moisture, which is advantageous during humidification and cooling. In addition, it has the advantage of low noise, easy installation and disposal, and maintains the existing HEPA efficiency (H13, 99.97%) while maintaining the air volume even in a narrow space.

1 is a diagram illustrating internal air circulation in a clean room in which a heterogeneous material composite HEPA filter according to the present invention is installed.
2 is a view schematically showing a heterogeneous material composite HEPA filter according to the present invention.
3 and 4 are test reports of the heterogeneous material composite HEPA filter according to the present invention.
5 and 6 are photographs of the final product of the heterogeneous material composite HEPA filter according to the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used with meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs.

In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

Hereinafter, a heterogeneous material composite HEPA filter according to the present invention will be described in more detail.

In an embodiment of the present invention, as shown in FIG. 2, the heterogeneous material composite HEPA filter according to the present invention includes a first filter layer and a second filter layer each including synthetic fibers, and the average fiber of the first filter layer The diameter may be different from the average fiber diameter of the second filter layer.

The first and second filter layers of the heterogeneous composite HEPA filter according to the present invention each include synthetic fibers having different average fiber diameters, thereby reducing pressure loss and increasing dust collection efficiency. In addition, due to the structure including synthetic fibers having different average fiber diameters, when the high-functional filter is used in a filter device using a corona charging method, it is possible to prevent a decrease in filter life.

When the fiber diameters of the filter layers are similar, when the energy of the corona charging method flows for a certain period of time, the differential pressure increases at a high speed and the efficiency decreases. In the present invention, by making the average fiber diameters of the first and second filter layers different, it is possible to collect particles having different diameters by varying the pore size between the fibers of the first and second filter layers, thus reducing the service life of each filter. There is an advantage that it can be extended.

The heterogeneous material composite HEPA filter according to the present invention may have a differential pressure of less than 5.5 mmaq and a filtration efficiency of 99.98% or more when the ^{treatment capacity is 32 m 3 /min.}

The differential pressure of a commonly used filter ranges from 25 to 30 mmaq at a processing capacity ^{of 32 m 3 /min.} Therefore, if the processing capacity is further increased, the differential pressure becomes too large, making it difficult to use, and serious problems such as a sharp reduction or breakage of the life of the filter may occur.

However, the heterogeneous material composite HEPA filter according to the present invention has a differential ^{pressure of only 5.5mmaq at a processing capacity of 32m 3} /min, and even if the processing capacity is ^{increased to 56m 3} /min, the differential pressure is about 14.8mmaq, remarkably compared to the differential pressure of the existing filter. As it is low, there is an advantage in that power consumption is low during use and air circulation is smooth, so that the cleanliness inside the clean room can be easily maintained.

In one embodiment of the heterogeneous material composite HEPA filter according to the present invention, the synthetic fibers included in at least one of the first filter layer and the second filter layer of the low differential pressure high functional filter are melt-blown. Can be formed. The melt blown method is a method of laminating ultrafine fibers, which are fined by hot air sprayed at high speed from a spinneret formed of hundreds of small orifices, of a thermoplastic polymer on a collector, thereby producing ultrafine fibers with a fiber diameter of 0.3-5㎛. There is an advantage in that it has excellent flexibility, impermeability, insulation, and barrier properties, and is excellent in filtration performance when electrostatic performance is given.

In addition, the wide range of materials to choose from makes it easy to implement desired physical properties such as incineration ability, resolution, tensile strength, formability, and water repellency.

In one embodiment of the heterogeneous material composite HEPA filter according to the present invention, as shown in FIG. 2, a nonwoven filter layer may be further included between the first filter layer and the second filter layer. By further including a nonwoven filter layer between the filter layers, it is possible to have an effect of enhancing collection capacity and improving moldability and durability. In addition, the non-woven filter layer may be a conventional positive charge coating-treated non-woven fabric and/or polypropylene non-woven fabric having an average pore size of 1 µm to 2 µm, preferably an average pore size of 1 µm to 1.8 µm.

At this time, if the average pore size is less than 1 μm, the amount of filtration decreases, so that a sufficient cumulative amount of filtration may not be secured. If the average pore size exceeds 2 μm, the amount of filtration increases, but filtration performance may deteriorate. In addition, the polypropylene melt blown-calendering nonwoven fabric of the present invention may have an average thickness of 100 µm to 250 µm, preferably an average thickness of 120 µm to 220 µm, and more preferably 150 µm to 175 µm.

If the average thickness of the polypropylene meltblown-calendaring nonwoven fabric is less than 100㎛, the filtration performance may decrease, and if the average thickness exceeds 250㎛, the filtration amount decreases, there is no further improvement in filtration performance, and the cumulative filtration amount is rather reduced. There may be a problem that the use cycle is shortened.

The positively charged coating-treated nonwoven fabric is a modified nonwoven fabric; And a positively charged coating layer on the inside and the surface of the nonwoven fabric, wherein the positively charged coated nonwoven fabric may have a surface charge of 10 mV to 40 mV, preferably 20 mV to 40 mV.

The modified nonwoven fabric of the positively charged coated nonwoven fabric is a modified nonwoven fabric with the interior and/or surface of the nonwoven fabric modified, and the nonwoven fabric is applicable as long as it is commonly used, and preferably, chemical bonding, thermal bonding nonwoven Thermal Bonding), Air Ray, Wet Ray, Needle Punching, Spanless (Water Jet), Spun Bond, Melt Blown ), it may be in any one form selected from a stitch bond and an electro spinning nonwoven fabric.

In addition, the fibers constituting the nonwoven fabric include at least one selected from polypropylene fibers, polyethylene terephthalate fibers, polyethylene fibers, polyester fibers, nylon fibers and cellulose fibers, preferably polypropylene fibers, polyethylene terephthalate fibers, polyethylene One or two or more selected from fibers and polyester fibers, more preferably one or two selected from polypropylene fibers and polyethylene terephthalate fibers may be included.

In addition, the modified nonwoven fabric has an average thickness of 0.1 mm to 2 mm, preferably 0.2 mm to 1 mm. In this case, the average thickness 0.1 If the average thickness is less than 0.1 mm, the adsorption path is short and the removal efficiency is reduced. There is a reduced problem, and if it exceeds 2mm, there may be a problem that the amount of filtration decreases due to the occurrence of differential pressure during filtration.

In addition, the average fiber diameter of the fibers constituting the modified nonwoven fabric may be 0.5㎛ ~ 10㎛ and average pores 1㎛ ~ 30㎛, preferably the average fiber diameter 0.5㎛ ~ 8㎛ and average pores 1㎛ ~ 10 It may be ㎛, more preferably an average fiber diameter of 0.5㎛ to 5㎛ and may be an average pore size of 1㎛ to 8㎛.

At this time, if the average fiber diameter of the fibers constituting the nonwoven fabric is less than 0.5 μm, there may be a problem that the amount of filtration decreases due to the occurrence of differential pressure during filtration, and if it exceeds 10 μm, there may be a problem that the porosity decreases and the filtering performance decreases I can. In addition, when the average pore size is less than 1 μm, the flow rate may decrease, and when it exceeds 30 μm, there may be a problem that the filtration performance decreases.

In addition, the positively charged coating layer constituting the positively charged coated nonwoven fabric contains a multifunctional amine compound, and the multifunctional amine compound serves to impart an electrostatic property showing a positive charge to the inside and outside of the modified nonwoven fabric, and polyethylene One or two or more selected from imine, diethylenetriamine, piperazine, dimethylene piperazine and diphenylamine may be used in combination, and preferably one or two selected from diethylenetriamine and diphenylamine More than one species can be mixed and used.

In addition, the positively charged coating layer is preferably formed with an average thickness of 0.01 μm to 3 μm, preferably 0.05 μm to 1 μm, and at this time, the average thickness of the positively charged coating layer is 0.05 μm. If the average thickness exceeds 3 μm, the coating layer may be deteriorated in durability and the coating may be peeled off, and since there is no further increase in filtration performance, it is preferable to form a positively charged coating layer to have an average thickness within the above range.

The heterogeneous material composite HEPA filter according to the present invention may have a shape that is refracted multiple times so that the shape of the filter cross section has peaks and valleys, but the shape of the filter is flexible by those of ordinary skill in the art. Can be determined.

Further, in an embodiment of the heterogeneous material composite HEPA filter according to the present invention, the first average fiber diameter, which is the average fiber diameter of the synthetic fibers included in the first filter layer, may be 1.0 μm to 10 μm, and the second filter layer The second average fiber diameter, which is the average fiber diameter of the synthetic fibers included in, may be 0.1 μm to 1.0 μm.

When the first average fiber diameter is less than 1.0 μm, there is a concern that pressure loss may increase, and when it is larger than 10 μm, efficiency and/or moldability of the filter may be deteriorated. The second average fiber diameter is most preferably in the range of 0.1 μm to 1.0 μm in terms of pressure loss and filtering efficiency, and preferably not equal to the first average fiber diameter even if it falls within the above range.

For example, it is not preferable when both the first average fiber diameter and the second average fiber diameter are 1.0 µm. If the average fiber diameters of the two filters are similar, the differential pressure may be further lowered, but foreign substances of various particle diameters cannot be removed, and thus, a problem may occur in filtration performance. In addition, when the energy of the corona charging method passes for a certain period of time, the differential pressure increases and the efficiency decreases.

In one embodiment of the heterogeneous material composite HEPA filter according to the present invention, the synthetic fibers constituting each of the filter layers include polyolefins including polyethylene, polypropylene, polybutylene, polyisobutylene, and the like; Polyglycolide, polylactic acid, polycaprolactone, polyhydroxyalkanoate, polyhydroxybutyrate, polyethylene adipate, polybutylene succinate, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate , Polyester including polyethylene naphthalate, and the like; Polyamides including aliphatic polyamides (eg nylon), polyphthalamides, aramids, and the like; And one or more selected from the group consisting of polyphenylene sulfides such as linear and crosslinked, but are not limited thereto.

Preferably, the synthetic fiber may include polypropylene and polyethylene terephthalate. The synthetic fiber formed by the melt blown method has the advantage of low pressure loss and high efficiency. In particular, synthetic fibers made of polypropylene and polyethylene terephthalate as raw materials have inherent electrostatic power to improve charging and filtration efficiency, and improve filter life when used in a filter device using a corona method.

In an embodiment of the present invention, the first filter layer and the second filter layer, or the first filter layer, the nonwoven filter layer, and the second filter layer may be laminated by an ultrasonic lamination method.

By using the ultrasonic lamination method, the bonding between the filter layers and/or the filter layers and the nonwoven fabric is more robust, minimizes undesirable effects on filter performance, and prevents additional pressure loss due to the use of foreign substances such as adhesives. I can. In addition, it can be expected to increase the life of the material and save energy.

Hereinafter, the low differential pressure high functional filter according to the present invention will be described in more detail through Examples and Comparative Examples, but the present invention is not limited to the following Examples.

All of the following Examples and Comparative Examples were tested under the same conditions (thickness 0.3mm, 610*610*292T, 60Pleate, etc.).

Example 1

Polypropylene and polyethylene terephthalate synthetic fiber layer (first filter layer) and non-woven fabric layer manufactured to have an average fiber diameter of 5 μm by a melt blown method, and polypropylene and polyethylene manufactured to have an average fiber diameter of 0.5 μm by a melt blown method The terephthalate synthetic fiber layer (the second filter layer) was ultrasonically laminated to prepare a high-functional filter of 610*610*292T standard (Figs. 3 and 4), and the performance was measured and shown in Table 1 and Figs. 5 to 6 below. .

Comparative Example 1

A high-functional filter of 610*610*292T standard was manufactured using glass fibers, and the performance was measured and shown in Table 1 below.

Comparative Example 2

A high-functional filter of 610*610*292T standard was prepared using a general polypropylene synthetic fiber, and the performance was measured and shown in Table 1 below.

Comparative Example 3

In Example 1, the same as in Example 1, except that the average diameter of the synthetic fibers of the first filter layer and the average diameter of the synthetic fibers of the second filter layer are the same as in Example 1 610 * 610 * 292T standard high functionality A filter was prepared, and the performance was measured and shown in Table 1 below.

HEPA FILTER 610*610*292T (60Pleate) Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Filtration efficiency 99.97% 99.97% 99.91% 99.98% Foreclosure 25.4 mmaq 27.0 mmaq 5.0 mmaq 5.1 mmaq Treatment air volume 32 m ³ /min 32 m ³ /min 32 m ³ /min 32 m ³ /min

As shown in Table 1, it can be seen that the filter of Example 1 has less pressure loss and lower initial static pressure than the filters of Comparative Examples, so that the conditions required by the low differential pressure high functional filter are evenly provided. In other words, the filtration efficiency exceeds 99.97% (H13 grade, True HEPA efficiency), and the differential pressure is very low, about 5mmaq, so it is possible to filter foreign substances with high efficiency even though the amount of power consumed in the clean room is low, so it is applied to the actual clean room. In this case, even if the throughput is increased, the inflow of foreign substances is effectively prevented and the filter life is not shortened due to the filter breakage or clogging due to a large differential pressure. In fact, even when the processing capacity of the filter of Example 1 ^{was increased to 56 m 3} /min, the differential pressure was about 14.8 mmaq, which was significantly lower than that of the conventional filter.

Specifically, in the case of Comparative Example 1, which is a filter manufactured using a conventional glass fiber, the filtration efficiency using the glass fiber satisfies 99.97%, but the differential pressure is 25.4mmaq, which is high. This is also the case of Comparative Example 2, which is a filter manufactured using a conventional melt blown fiber, and it can be expected that the possibility of shortening the lifespan due to damage or clogging of the filter due to the high differential pressure is very high.

Comparative Example 3 is a filter manufactured by laminating melt-blown fibers into two layers as in the example of the present invention, and is the same filter as in Example 1 of the present invention, except that the fiber diameters of the two layers are the same. The filter of Comparative Example 3 uses a medium having the same fiber diameters and a larger fiber diameter than the first filter layer of the present invention, so that the differential pressure is lower than that of the first filter layer of the present invention, but the filtration efficiency is 99.91%, and H13 class HEPA efficiency. You can see that you are not satisfied with

Claims (10)

A heterogeneous composite filter comprising a fluororesin HEPA filter and a melt blown HEPA filter, a first filter layer and a second filter layer, wherein the average diameter of synthetic fibers included in the first HEPA filter layer is the second HEPA filter layer A heterogeneous composite HEPA filter comprising a fluorine filter and a HEPA filter, characterized in that it is larger than the average diameter of the synthetic fibers contained in the fiber. The heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter according to claim 1, wherein the synthetic fibers included in at least one of the first and second filter layers are manufactured by a melt blown method. The heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter according to claim 1, further comprising a nonwoven filter layer between the first filter layer and the second filter layer. The heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter according to claim 1, wherein the synthetic fibers contained in the first filter layer have an average fiber diameter of 1.0 µm to 10 µm. The heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter according to claim 1, wherein an average fiber diameter of the synthetic fibers included in the second filter layer is 0.1 µm to 1.0 µm. The method of claim 6, wherein the synthetic fibers included in the first and second filter layers are made of one or more materials selected from the group consisting of polyolefin, polyester, polyamide, and polyphenylene sulfide. A heterogeneous hybrid HEPA filter of a fluorine filter and a HEPA filter. The heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter according to claim 1, wherein the synthetic fibers are made from polypropylene and polyethylene terephthalate, respectively. The heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter according to claim 1, wherein the first filter layer and the second filter layer are laminated by an ultrasonic lamination method. The heterogeneous hybrid HEPA filter of a fluorine filter and a HEPA filter according to claim 3, wherein the first filter layer, the nonwoven filter layer, and the second filter layer are laminated by an ultrasonic lamination method.
A heterogeneous composite filter comprising a fluororesin HEPA filter and a melt blown HEPA filter, a first filter layer and a second filter layer, wherein the average diameter of synthetic fibers included in the first HEPA filter layer is the second HEPA filter layer A heterogeneous composite HEPA filter of a fluorine filter and a HEPA filter, which is larger than the average diameter of the containing fibers and has a filtration efficiency of 99.98% or more.

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