Method to produce filtration material, filtration material and respiratory system protector
FIELD: process engineering.
SUBSTANCE: invention relates to production of polymer fibrous filtration materials and covers the method of electroforming 1-10 mcm diametre fibers from 5% to 20% by weight of polymer solution in organic solvent that features viscosity of 3.5 to 5.0 p at electroforming voltage of 60 to 140 kV. In compliance with this method, the used polymer used represents chlorinated polyethylene or polypropylene with chlorination of 64-66% and molecular weight of (2-15) 105. Material, thus produced, is used for protection of respiratory system when applied on dressed gauze substrate.
EFFECT: higher protective properties.
3 cl, 8 tbl
The invention relates to the field of production method electrotorture fibrous polymer filter materials used for respiratory protection and the environment from toxic aerosols.
The essence of the method of electrotorture is getting when creating the electrical potential difference ultrathin (1-10 μm) polymer fibers from a solution of fibre-forming polymer, followed by deposition of fibers on a substrate or without it.
Under the influence of an electric field occurs neutralization of the forces of surface tension of the solution, with the result that he comes in the form of a thin thread from the metering device, which is the pole of the high voltage, and is split into many thinner filaments. During evaporation of the solvent thread turn into dry fibers that are deposited on opposite charged the receiving electrode.
The basis of the method, the characteristics obtained with its use of filter materials and their use are described in detail in the book Aaguilera "Production and properties of filter materials Petryanov of ultrathin polymer fibers", Moscow, 2007, p.16-96, 156-164, and the book Y.N. Filatov "Electropermanent fibrous materials SAFV-process): Oil and gas, 1997, p.3-7.
A method of obtaining the filtering material from which alimera styrene with Acrylonitrile diameter fibers 1-10 μm of the spinning solution, containing dichloroethane, electrolytic additives and solvents from the series: acetone or methyl ethyl ketone, or ethyl acetate, or butyl acetate (patent RU 2182511, 01039/16, 2002.05.20).
The disadvantage of this method is that the filter material obtained on its basis has a low mechanical strength.
A method of obtaining the filter FPP-15-1,5 on THE other 6-16-2813-84; FPP-15-1,0 on THE other 6-16-2502-81; FRR-15-0,8 on THE other 6-16-2090-84; FRR-15-0,6 on THE other 6-16-2571-85 based on processing of 10-12 wt.% spinning solution of PVC resin chlorinated in dichloroethane method electrotorture with the subsequent imposition of fibers on a substrate made of gauze or cloth glued. As technological additives to control viscosity and conductivity of the spinning solution and the velocity of the fiberizing is ethyl alcohol. To control the conductivity of the solution is also injected electrolytic additives. This method allows you to get the filter material FRR with different security characteristics. The disadvantage of this method is the relatively low tensile strength of the fibrous layer (0,49-1,18 N, 0,05-0,12 kg).
Known fibrous filter material of a copolymer of styrene with methyl methacrylate and Acrylonitrile containing fiber 6-10 mm in the amount of 70-80% and a fiber diameter of 1-2 m is the number of 20-30%, and the way it is received by electrostatic molding of the polymer solution in an organic solvent (patent RU 2049525, V 039/16, publ. 1995.12.10).
This material is not a high mechanical characteristics.
Known fibrous filter material FPP-15-1,5 on THE other 6-16-2813-84 FRR-15-1,0 on THE other 6-16-2502-81 FRR-15-0,8 on THE other 6-16-2090-84 FRR-15-0,6 on THE other 6-16-2571-85 with the following indicators presented in table 1.
This material is not a high mechanical characteristics.
Known means of respiratory protection by patent 2182511 (publ. 2002.05.20), containing a working layer of polymer fibers with a diameter of 1-10 μm, the protective layer of gauze and filter holder, and the working layer is made of fibers of a copolymer of styrene with Acrylonitrile, with a surface density of 20-80 g/m2and aerodynamic 3-60 PA at the air flow rate of 1 cm/S.
The disadvantage of this means of respiratory protection is the low mechanical strength of the used filter material.
The invention solves the task of developing a method of producing a filtering material, which allows to obtain the filter material with high mechanical characteristics while maintaining the protective characteristics required for the use of this is about material in the media for respiratory protection.
The problem is solved by the described method of obtaining the filter material by electrotorture fiber with a diameter of 1-10 μm, from 5-20 wt.% the polymer solution in an organic solvent, having a viscosity of 3.5-5.0 Poises when the voltage electrotorture 60-140 kV, whereas the polymer used chlorinated polyethylene or polypropylene of high class polyolefins having a degree of chlorination of 64-66% and molecular weight (2-15)·105. This choice is based on the following main properties of the polymer, causing the desired properties of the product, namely the ability to form stable homogeneous solutions when dissolved in certain organic solvents, water repellency combined with high electrical resistance, high chemical resistance to acids and alkalis, high thermal resistance, high tensile strength and relative elongation.
The problem is solved also by the filter material obtained by the method described above, and as the polymer used chlorinated polyethylene or polypropylene having a degree of chlorination of 64-66% and molecular weight (2-15)·105.
The task is also solved by means of respiratory protection, containing a working layer of polymer fibers, and as the floor is the measure used chlorinated polyethylene or polypropylene, having a degree of chlorination of 64-66% and molecular weight (2-15)·105.
Thanks to the claimed method, the obtained filter material with improved mechanical properties, and the filter material has the required properties for the manufacture of personal protective equipment.
Examples obtain the filtering material is presented in table 2, 3.
Prepare 5-20 wt.% the spinning solution is highly polyethylene or polypropylene having a degree of chlorination of 64-66% and molecular weight (2-15)·105in organic solvents (see table 2). The solution should be homogeneous (without admixture of solid particles), i.e. the polymer is completely soluble in the selected solvent. In the prepared solution specified mass concentration is determined by the dynamic viscosity. As a technological additive for regulating the conductivity of the used solution tetraethylammonium in ethanol (see table 2). Then spend electropermanent fibrous layer is in the range electrical voltage 60-140 kV and the pressure of the spinning solution of 0.6-2.0 kgf/cm2.
As shown by laboratory tests obtained in accordance with the invention, the filter materials are fibers with an average diameter of 1-10 μm, have a high protective characteristics, namely: the ratio of Pronichev the standard oil mist with an average particle radius of 0.15-0.17 microns at a speed of 1 cm/s from 0.0002 to 0.12, improved mechanical properties (tensile load from 2.1 to 4.3), the resistance to air flow of 0.5-1.35mm Vogt (4,9-13,23 PA) at a flow rate of air of 1 cm/s, the relative elongation in the range 0.4-0,66 (see table 3).
Described filter material was manufactured at the production plant JSC "Sorbent", from which the pilot batch of personal respiratory protection type "Petal", "2K", containing a working layer of declared material deposited on a substrate of the finished Marley and tested respirators type f-62, RPG-67, RU-60M, which gave a positive result.
|Characteristics of filter materials based on high density polyethylene and polypropylene|
|The name of the filter material on the basis of the spinning solution (No. of example 1)||Technological parameters of manufacturing||Quality material|
|Voltage, kV||Pressure solution, kgf/cm2||The resistance is a group of the airflow at a design speed of 1 cm/sec, mm Vogt (PA)||The coefficient of permeability for oil mist when the estimated speed of 1 cm/sec, %||The surface density of the fibrous layer, g/m2||The breaking load of the fibrous layer, N||Elongation at break fiber. layer|
|No. 1||80||1,2||0,64 (6,27)||0,03||26,9||3,0||0,49|
|No. 2||120||1,4||1,0-1,2||0,006||39,3||a 3.9||0,48|
|No. 4||120||1,8||0,80 (7,84)||0,0004||to 47.2||4,3||0,40|
|No. 5||60||1,0||0,55 (5,39)||0,12||20,5||2,1||0,54|
|No. 6||120||0,7||0,75 (7,35)||0,04||30,3||3,2||0,56|
|No. 7||110||0,6||1,05 (10,29)||is 0.0002||31,3||the 3.8||0,56|
|No. 8||110||0,6||0,78 (of 7.64)||0,002||18,1||0,56|
|No. 9||100||0,6||0,6 (5,88)||0,06||to 25.3||2,8||0,5|
|No. 10||100||0,6||0,5 (4,9)||0,6||24,0||2,8||0,49|
|No. 11||110||0,7||1,5 (14,7)||0,0004||31,6||the 3.8||0,48|
|No. 12||110||0,6||1,05 (10,29)||0,0004||31,3||the 3.8||0,56|
|No. 13||110||0,6||0,78 (of 7.64)||0,002||18,1||2,6||0,48|
|No. 14||110||0,6||0,78 (of 7.64)||0,002||18,1||2,9||0,58|
|No. 15||110||0,7||0,85 (8,33)||0,002||20,0||2,4||0,61|
|No. 16||120||0,7||0,92 (9,02)||0004||23,2||2,8||0,56|
|No. 17||120||0,7||0,92 (9,02)||0,003||23,2||2,7||0,66|
1. The method of obtaining the filter material by electrotorture fiber with a diameter of 1-10 μm, from 5-20 wt.% the polymer solution in an organic solvent, having a viscosity of 3.5-5.0 P when the voltage electrotorture 60-140 kV, characterized in that the polymer used as chlorinated polyethylene or polypropylene having a degree of chlorination of 64-66% and molecular weight (2-15)·105.
2. The filter material consisting of a layer of polydisperse electrically charged ultrafine polymer fibers, characterized in that it is obtained by the method described in claim 1.
3. Remedy for respiratory protection, containing a working layer of polymer fibers with a diameter of 1-10 μm, the protective layer of gauze and filtrowanie the spruce, characterized in that it comprises a working layer of fibres obtained by a method characterized in claim 1.
FIELD: machine building.
SUBSTANCE: material corresponds to track membrane on base of poly-ethylene-terephtalate with average disperse dimension of open pores from 10 nano-metres to 3 microns, surface of which contains poly-siloxane block copolymer. The procedure consists in dissolving poly-siloxane block copolymer in solution of toluene containing complexes of fullerenes C60, in treating the track membrane on base of poly-ethylene-terephtalate with prepared solution and in its drying till removal of toluene.
EFFECT: production of material with reduced adhesion properties of surface, with simplified procedure of cleaning and with capability to eliminate micro-organisms present in water.
2 cl, 2 ex
SUBSTANCE: non-woven textile is proposed, having air-permeable adsorbent carrier particles, duplicated on at least one side by air-permeable layer of material with an adhesive layer, and which is non-woven fibre material with specific mass ranging from 90 to 120 g/m2. Specific mass of non-woven material which is duplicated by the fibre non-woven material ranges from 20 to 40 g/m2, and dimensions of the adsorbent range from 0.3 to 1.0 mm.
EFFECT: invention widens the range of high-efficiency sorption-filtering materials.
FIELD: production processes.
SUBSTANCE: invention refers to fine purification of air from particulate pollutants and gases, from carbon monoxide in particular by means of nonwoven filter materials. Presented multilayer filter material from polysulphon consists of three layers, at that second (working) layer is made of fibers with diametre from 5 to 9 mcm, with surface density 40-50 mg per cm2, free volume from 95 to 98% and average dimension of pores is from 20 to 40 mcm, surface density of first and third (protective) layers is 15-30 mg per cm, they are made of fibers with diametre 1-3 mcm, with free volume from 94 to 97% and average dimension of pores is from 4 to 12 mcm.
EFFECT: invention ensures possibility of effective inclusion of dispersed phase with sorbing or catalytical properties in filter material structure.
3 cl, 3 tbl
FIELD: treatment facilities.
SUBSTANCE: invention is related to filtering materials for cleaning of gaseous medium, in which nanosize first fibres of aluminium oxide and second fibres are arranged in the form of matrix with formation of asymmetric pores, at the same time each of specified second fibres has diametre in the range from approximately 0.6 mcm to approximately 3.5 mcm, at the same time asymmetric pores have average size of more than approximately 10 mcm and less then approximately 38 mcm, material may retain particles, size of which is many times less than specified pore size.
EFFECT: according to invention, filter has high efficiency of filtration and high absorbing property.
47 cl, 7 tbl, 14 dwg, 10 ex
SUBSTANCE: invention relates to making filtering materials for respirators. Filtering fibre material is proposed, as well as a method of making said material by electrostatic moulding microfibres from a polymer solution in an organic solvent. The material contains fibre of diametre 1-10 mcm from chlorinated polyethylene, characterised by mass content of chlorine of 60-70%, has surface density of 20-60 g/m and is used as the working layer of the respirator.
EFFECT: high mechanical strength of the material with high retention potential.
FIELD: textile fabrics, paper.
SUBSTANCE: invention is related to the field of water treatment. Filtering element for drinking water treatment is made in the form of bobbin wound at the angle of 12°-15° onto porous cylinder by two parallel cords with thickness of 1-2 mm from polymer ion-exchange fibre in mixture with activated carbon particles, besides one cord is arranged with the right twist, and the second one - with the left twist.
EFFECT: full use of filtering material components.
FIELD: textile fabrics, paper.
SUBSTANCE: invention is related to multilayer filtering materials. Suggested nonwoven material consists of inlet and outlet layers. Outlet layer consists of main and additional sublayers previously attached to each other. Inlet layer and main sublayer of outlet laye consist of mixture of hollow silicone fibre with linear density of 0.68 tex and polypropylene fibre with linear density of 2 tex, and additional sublayer of outlet layer consists of polypropylene fibre with linear density of 0.68 tex. Ratio of surface densities of inlet and outlet layers makes 1:1÷1:1.5.
EFFECT: improved operational properties.
FIELD: means of protection.
SUBSTANCE: invention relates to production of a filtering and sorbing material used in the means of personal respiratory protective equipment to cleanse the air form fumes and aerosols of hazardous substances. The filtering and sorbing material containing polypropylene fibers filled with microatomised carbon, fibers of sulfate unbleached cellulose and fibers of mercerised cellulose is obtained by adding the polypropylene fibers in the amount 5-10% of the total mass at the stage of grinding the sulfate unbleached cellulose after which combined grinding of the mixture is continued until the grinding degree of 28±2°SHR is reached, the mixture is then mixed with the fibers of mercerised cellulose and carbon, paper web is poured dried and treated with an impregnating solution containing nickel chloride (II) - 10%, ferrous chloride (III) - 10%, copper chloride (II) - 10%.
EFFECT: production of elestic well draped filtering and sorbing material with high mechanical and adsorbtion characteristics and a low aerodynamic resistance to respiration.
1 tbl, 1 dwg
SUBSTANCE: method involves as follows. Electroformed nonwoven fibrous polymer fabric is impregnated with aqueous or aqueous-alcoholic suspension of aluminium material particles then hydrolysed by heating the suspension impregnated fabric that is impregnated by suspension spraying over its surface. The heating process in performed in the open air at relative humidity at least 70%, preferentially 95-100% of at least two stacked suspension impregnated fabrics. Upon termination of hydrolysis process, plane parallel wringing of the fabrics follows.
EFFECT: improved performance of a sorbent owing to formation of the composite sheet sorbent involving uniform distribution of porous particles of oxide-hydroxide aluminium phases over the entire volume of the fabric, formation of the sheet sorbent fabric of uniform thickness and density.
7 cl, 2 ex, 1 tbl
FIELD: technological processes.
SUBSTANCE: invention is related to the field of fibrous filtering materials. Filtering material is suggested for respirators, which contains working layer of fibres with diametre of 1-10 mcm produced by method of electrostatic moulding from solution containing 6-16 wt % of polycarbonate in mixture of dissolvents that consists of dichloroethane and methylene chloride with their mass ratio of (1-5):(9-5), accordingly, and having surface density of 30-60 g/m2. Respirator is made with application of produced material.
EFFECT: improved mechanical strength of material and products on its basis.
4 cl, 1 dwg, 2 tbl
FIELD: methods of production of electret items, electret filters and respirators.
SUBSTANCE: the invention presents a method of production of electret items, electret filters and respirators with heightened resistivity to the oil mist. The invention falls into production processes of electret items, electret packed beds and respirators, and may be used for removal of corpuscles from gases, especially for removal of aerosols from air. The method provides for: formation of a melted material consisting of a mixture of a polymer composed of a mixture of a polymer representing a non-current-conducting thermoplastic resin with a specific resistivity exceeding 1014 Ohms·cm with a fluorine compound as an additive compound; shaping it to the required form and quenching it up to the temperature lower than the melting point of the polymer. The material is calcined and treated with an electric charge to give it electret properties. The invention improves the capability of filtering oily aerosols.
EFFECT: the invention improves the capability of filtering oily aerosols.
19 cl, 16 tbl, 19 dwg, 23 ex
FIELD: methods for imparting charge to fibrous webs by means of non-aqueous liquid for usage of said webs as filters in filtering face masks for protection of user's mouth and nose.
SUBSTANCE: method involves wetting web formed from non-conductive fibers with non-aqueous polar liquid; substantially drying web for producing fibrous electronic web. Method differs from known methods of imparting charge to web in that it requires less energy for drying of web than methods using aqueous liquids. Also, many kinds of filaments poorly wetted with aqueous liquids are immediately wetted with non-aqueous liquids.
EFFECT: increased efficiency and simplified method.
12 cl, 2 dwg, 6 tbl, 26 ex
FIELD: fine-fiber filtering materials.
SUBSTANCE: the invention is pertinent to fine-fiber filtering materials used for individual means of protection of respiratory organs. The invention offers a protection material, a means of protection containing the offered material and a method of production of the fibrous material providing for electrostatic forming of the fibrous material from a solution of styrene copolymer with acrylonitrile in an organic solvent at the presence of electrostatic additives of bromide or iodide salts of tetraethyl- or tetrabutyl-ammonium. At that a solution containing an additive of a high-molecular methylmethacrylate in amount of 0.001-0.01 mass % in the capacity of dissolvent is used a mixture of ethyl acetate with butyl acetate at their mass ratio in the solution from 1/9 up to 9/1 accordingly. The invention allows to produce a material with improved mechanical characteristics and to provide stability of the production process.
EFFECT: the invention ensures production of the material with improved mechanical characteristics and stability of the production process.
5 cl, 2 tbl, 1 ex
FIELD: fine filtration of air; cleaning ventilation emissions from oil mist; cleaning air in venting pipe lines of gas-transfer unit oil tanks.
SUBSTANCE: proposed filter includes filter element with filter medium made from coarse and fine fibers laid in between outer and inner cylinders, cover and bottom. Filter medium is made from longitudinal and transversal oil-resistant synthetic (polypropylene) fibers; ratio of mass of longitudinal and transversal fibers is equal to (6-8) : 1 and ratio of diameters of thin and coarse fibers is equal to (0.5-1) : 10.
EFFECT: enhanced efficiency of cleaning at considerable increase of service life, oil return coefficient; enhanced ecological safety around compressor stations.
2 cl, 2 dwg
FIELD: filtering materials for liquid and gaseous fluids.
SUBSTANCE: filtering material is made of thermoplastic polymeric fibers. The density of material increases downstream, whereas the diameter of fibers decreases downstream. The inner layer of the material has areas the density of fibers in which is lower than the averaged density of upper layers by a factor of 2-6.
EFFECT: enhanced strength.
1 dwg, 1 tbl
FIELD: polymer materials and gas treatment.
SUBSTANCE: invention relates to polymeric fibrous filter materials designed for effective cleaning of air stream due to realization of mechanical and electrostatic filtration. Material suitable for use in respiratory masks contains (i) a layer in the form of cloth 1 mm thick made from polypropylene fibers with diameter 0.5-1.5 μm, packaging density 0.25-0.30 g/cm3, and electric charge with surface density 17-21 nCl/cm2, the layer being made by aerodynamic atomization of melt and electrization of fibers in corona discharge field during their formation, and (ii) an additional layer in the form of non-electrized cloth 1 mm thick made from polypropylene fibers with diameter 10-20 μm and packaging density 0.25-0.30 g/cm3, which is placed on the side directly facing air stream to be cleaned, the two layers being attached to each other by spot weld. Presence of two layers results in separate but complementary realization of mechanical and electrostatic filtration.
EFFECT: enhanced air cleaning efficiency and prolonged lifetime of filter material.
FIELD: methods and devices used for production of fibrous electret linen.
SUBSTANCE: the invention is pertaining to methods and devices used for production of fibrous electret linen. The method of giving of an electrostatic charge to the fibrous non-woven linen provides that the fibrous linen is soaked with a wetting liquid, then it is saturated with a water polar liquid and dried. The gained dry product represents an electret, which may be efficiently used in the air filters, for example, in respirators.
EFFECT: the invention ensures production of a fibrous electret linen, which may be efficiently used in the air filters, for example, in respirators.
13 cl, 3 ex, 5 tbl, 4 dwg
FIELD: chemical industry; oil refining industry and other industries.
SUBSTANCE: the invention is pertaining to production of materials for the filtering water-separating elements used in devices for purification of organic fluids, predominantly, hydrocarbon fuels, oils, oil products from the emulsified water and mechanical impurities, and may be used for purification of aircraft and car fuels in chemical industry, oil refining industry and other industries. The porous reinforced material is produced out of a permeable in all directions polymeric material with a side-porous deep structure having a total porosity of no less than 50 % with the sizes of the elementary pores, predominantly, of 10 - 200 microns. At that the porous reinforced material is formed out of a framed material having filaments or fibers with a diameter, predominantly, of 5 - 400 microns, and an arranged between the above mentioned filaments or fibers filler manufactured out of a porous polyvinyl formal produced by the method of a dew-point structurization with the thermal treatment of a homogenized in water composition containing at least polyvinyl alcohol and aldehyde. The element for the screen-water-separator contains a filtering-coagulating septum embraced by a perforated shell rings and limiting from above and from below covers. At that the septum is made multilayered out of a sheet manufactured out of the above porous reinforced material. The technical result consists in an increased effectiveness of purification of fuels (jet engine fuels and diesel fuels) and the gaseous oil products from water, and also asphalt-resinous and sulfur-containing materials, an increased service life and productivity of the filtering screens based on the indicated filtering-coagulating material.
EFFECT: the invention ensures an increased effectiveness of purification of jet engine fuels, diesel fuels, gaseous oil products from water and also asphalt-resinous and sulfur-containing materials, service life and productivity of the filtering screens based on the filtering-coagulating material.
13 cl, 3 dwg
FIELD: methods of production of filtering materials.
SUBSTANCE: the invention is pertaining to the methods of production of filtering materials, in particular, to the method of production of the filtering fibrous materials, which may be used in a means of individual protection. The filtering fibrous material is produced by an electrostatic formation of a non-woven fibrous material from a working polymeric fiber-forming solution with dynamic viscosity of 1-30P, electrical conduction of 10-4-10-7 ohm-1 cm-1 in an electrostatic field at a potential difference from 10 up to 150 kV. The solution contains in the capacity of the polymer from 8.9 up to 24.6 mass % of styrene copolymer with 5.2-30.4 mass of acrylonitrile or triple styrene copolymer with 5.2-30.4 mass of acrylonitrile and 3.7-42.1 mass % of methyl methacrylate. As a dissolvent they use ethyl acetate, or butyl acetate either their mixture. The solution in addition contains high-molecular polymethyl methacrylate, a distilled water, the lowest alcohol taken from the group ethyl alcohol, methyl alcohol or isopropyl alcohol, at the following contents of ingredients of the polymeric fiber-forming solution, in mass %: polymeric compound - 8.9-24.6; high-molecular polymethyl methacrylate - 0.011-0.02; distilled water - 0.01-0.1; the lowest alcohol - 17-28; dissolvent - the rest. The efflux of the working polymeric fiber-forming solution is exercised at the volumetric speed of 0.1 up to 6 cm3 /minute. Feeding of the working polymeric fiber-forming solution is conducted from the space interval of 12-42 cm beginning from the point of its coming out from the batching device up to the settling surface. The produced filtering fibrous material contains a technological and a working layers made out of the polymeric fibrous material produced by the above described method. The technological layer material has the surface density of 1-3 g/m2 and is made out of fibers of 3-5 microns diameter. The working layer material is made out of fibers of 1.5-3 microns diameter. The double-layer material has the surface density of 32-38 g/m2, the standard resistance of 0.8-1.2 mm of the water column and the skip coefficient of no less than 95 %. The invention ensures an improved quality of the filtering material due to an increase of efficiency of penetration of fragments with a diameter of 0.3 microns at the standard resistance of 1.0 mm of the water column.
EFFECT: the invention ensures an improved quality of the filtering material, an increased efficiency of penetration of fragments with a diameter of parts of microns at the standard resistance of 1 mm of the water column.
4 cl, 2 ex
FIELD: natural gas industry; petrochemical industry; oil-producing industry; other branches of industry; methods of production of filtering materials and the filters for purification of gases and aerosols.
SUBSTANCE: the invention offers the filtering material made out of the polysulfone fibers with different diameter of the fibers produced by electromolding from the solution in the organic solvent with addition of an electrolyte; and the frame design filter supplied with the produced material having the density of 30 - 50 g/m2. The invention ensures the effective filtration of the aerosol particles at the high thermostability of the filter.
EFFECT: the invention ensures the effective filtration of the aerosol particles at the high thermostability of the filter.
5 cl, 1 tbl, 1 dwg