TW311096B - Airfilter, method for forming an electret nonwoven filter web, and eletret fiber nonwoven filter media - Google Patents

Abstract

There is provided a nonwoven electret fiber filter formed with a nonwoven web of electret fibers needle-punched to an open scrim support. The scrim support material has individual discrete open areas with an average cross-sectional area as viewed from the plane of the filter media of at least 0.25 mm2, preferably 1.0 mm2, and a pressure drop across the scrim support, without the filter web, of less than 1.5 mm H2O measured at 98.4 meters/min gaseous face velocity. The resulting filter has enhanced lifetimes, a low pressure drop and high filtration efficiencies.

Description

Μ Β7 3-U〇96 V. Description of the invention (1) Taking advantage of the scope of the invention The present invention relates to the products of green and human it / 1. ”The method of forming the electret nonwoven filter and its clear background The nonwoven mesh of the electret Laiwei is typically formed by electricity. This cry can be β Jiakou Ai in Jijie-incessantly or later filled with a non-woven net before and after the charge + merge code package For example, Wu Guo Patent 4,588,53 7 describes no electricity after forming, its Various methods can be used, including combing, brushing and blowing the nonwoven web without electricity. These nets are not recharging and the original fluffy form of money. In the US Patent 4,2l 5,682 (Kubik et al.), The fiber can also be charged when it is formed 'where the solution_blowing fiber can be bombarded by ions or electrons immediately after being squeezed from its solution_blowing nozzle 4 These fibers solidify very quickly in the atmosphere and are collected as half of the entangled micro-dimension. Withered clumps serve as the fiber web. The fiber web is described as preferably open to allow liquid to pass through the extinguisher formed by the fiber web with a low pressure drop. The fiber can also be charged as described in U.S. Patent 4,798,85. This patent describes blending different fibers together, which, when properly selected, will induce static electricity in these fibers when forming the fiber web. Other patents related to charging fibers or fiber webs include US patents 4,904, 174; 5, 122,048; 5, 4 01, 44 6, and 4,592, 8 1 5 ° US reissued patents 3〇, 7 82 (Van Turnout, etc.) Describe a particularly effective method of forming nonwoven electret fiber filters. In this patent, the electret fiber is a kind of corona-charged film (which is fibrillated to form a charge -4-This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297 public daughter) -1:- ------- "'outfit! (Please read the precautions on the back before filling in this page),-= * Printed by the Ministry of Economic Affairs Central Standards Bureau Employee Consumer Cooperatives Printed by the Ministry of Economic Affairs Central Standards Bureau Employee Consumer Cooperatives A7 B7 5. Description of the invention (2) Fiber) formation. The charged fiber is then formed into a nonwoven web by conventional methods such as combing or air stacking. This charging method provides a particularly high density of injected charge in the finished fiber. However From these pre-charged fibers, problems are often encountered when forming webs. These fibers are usually quite thick and non-crimped. They also resist blending. Partly because of these properties, these fibers resist forming a uniform adhesive web, especially on low benchmarks Weight. Part of US Patent 4,363,682 responds to this problem, and it advocates the use of such fibrillated fiber webs for military applications. To provide a more adhesive web and a type of fiber resistance, this special A post-embossing treatment method was proposed. After that, the embossing treatment welded the outer surface fibers together, claiming to provide a more adhesive and comfortable mesh for use as a mask. However, this treatment also tends to create a tighter mesh, which would Increase the pressure loss through the filter and reduce the life of the filter. US Patent 5, 2 3 0, 8 0 0 discloses an improvement to the embossing process. This patent proposes to needle the fibrillated electret fiber filter (for example, Via ν & η

Turnout, etc.) to a fabric support. The result is an integrated adhesive fiber filter composite with improved uniformity and transition properties. The researchers of the present invention are concerned about providing a non-woven electret fiber filter with a long / slow period and low pressure drop without losing the performance of the device, the device material can be economically and easily manufactured and easily converted into the final filter form. General description By using a nonwoven mesh of electret fibers on an open fabric support, a filter medium is obtained to obtain a nonwoven electret fiber filter medium and filter. &gt; An unsupported non-woven fiber filter is placed on the open 'female T Than Η' non-stretching fabric. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X 297 mm) Ί, ---------- 『装 ------ &quot; 訂 定 ——----- ~ li (Please read the precautions on the back before filling out this page) 一 ~ --_ Ministry of Economic Affairs 311096 A7 ________B7 printed by the employee consumer cooperative of the Central Bureau of Standards V. Description of invention (3) Supported materials. The fabric-supporting material has an individual discrete opening area, and the average cross-sectional area from the plane view of the filter media is at least 0 25 square mm, preferably 1_〇 square mm, and in the absence of the filter The pressure drop across the fabric at a surface velocity gauge of 98.4 meters / minute is less than 5 mm water column. The unsupported fiber filter and the fabric support are connected by needle punching the filter and the fabric support to form the filter media to provide a highly uniform non-woven fiber filter media with improved lifetime and filtration performance. At least some of the fibers that form the nonwoven fiber mesh are provided with electret charges. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of a preferred process configuration according to the method of the present invention. DETAILED DESCRIPTION The present invention relates to improvements to the invention disclosed in US Patent No. 5,23,800. This invention describes a fiber web and a support incorporating a fibrillated electret fiber by needle punching operation. The fabric method produces a filter medium in one way which is extremely uniform in its physical and performance characteristics. However, the present inventors are not only concerned about providing a filter medium having the uniformity of properties as discussed above in US Patent 5,230,800, but also concerned that a filter medium provides a high level of filtration efficiency for a long period of time at a higher gas surface velocity. Of particular concern is the provision of an excellent filter medium for the production of a high performance kiln filter, or a high performance universal air cleaning filter that must effectively filter large volumes of air for as long a life as possible. The filter body sacks must perform well at high gas surface velocities (eg, higher than 250 meters / minute), so they can be used as flat filters or folded filters to provide improved performance. Unexpectedly, it was found that by properly selecting the fabric support, borrowing needles ^ -6-This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) —. ^ ('. ^ ± 农 定 ^ (please Read the precautions on the back and then fill out this page) A7 B7 Printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention (4) 2 in one fiber filter layer is supported by the fabric to produce a kind of electret . The quasi-nonwoven fiber n 'media, which has both high surface performance and high life span at high gas surface speed. In particular, the filter fabric support of the present invention must be an extremely open material. There are a large number of divided opening areas, the opening area from the surface to the opposite side through the weave. These discrete opening areas must have an average cross-sectional area of at least 205 square axioms, at least 1 () square However, the size of the individual opening area can range from 0 ”square millimeters to 10 square millimeters or more. The opening area is preferably a non-distorted way through the fabric. The opening area Stretch directly from one side to the other (for example as a branch Column) is the best. Usually the ratio of the opening area through the average path length of the fabric to the average fabric thickness is from 3 to 1, which is better! And lower. The opening area of the fabric can also be an effective circular diameter (Effective Circular) Diametef (ECD) describes it as the diameter of the largest circle that can fit into an individual discrete opening area. The average E c D is usually at least 3 μm, preferably at least 500 μm. Although the fabric supports The extremely open nature of the material must be reasonably strong, and usually has a tensile strength of at least 50 kg / m, preferably at least 100 kg / m. The total pressure drop of the fabric material passes through the electret The pressure drop of a charged filter material must be relatively small (for example, less than 50% of the pressure drop of the filter, preferably less than 30%), and the gas surface velocity at # 98.4 m / min is around The conditions will be a pressure drop of less than 1.5 mm water column, preferably less than 10 mm water column, and less than 0.5 mm water column. The fabric material can be any suitable material such as a thermoplastic polymer, Paper ruler Applicable to China National Standard (CNS) A4 specification (210X297mm) Ί ------- 一 ·-装 ------- 訂 定 -------- (Please read the note on the back first Please fill in this page for details) A7 B7 Printed by the Workers ’Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy V. Description of Invention (5) Made of ductile metal or the like. The fabric should be made of thermoplastic fibers, such as a fabric or mesh material Such as the polyethylene fibers sold and sold by Am〇c〇 for each C1 of the product. Other fiber webs can also be used. The lamination is by conventional techniques such as heat, sound or adhesive lamination. For: If the child's final filter is to be folded, the fabric is also preferably foldable, so there is no need to use additional folds. If necessary, the foldable layer can be used. The fibrous mesh layer is a non-woven fibrous web in which at least-part of the fibers forming the web are individually supplied with electrostatic charges, commonly referred to as electret fibers. These electret fibers can be charged by known methods, for example, by using corona discharge electrodes or high-intensity electric fields, or by friction-charging (as described in U.S. Patent 4,798,850). These fibers may be charged during the formation of the fiber, before or during the formation of the fiber to become the screen, or after the formation of the screen. The fibers forming the filter can even be charged after being bonded to the fabric support layer. The non-woven fiber filter can be formed by conventional non-woven techniques, including melt blowing, carding, Rand〇, spunbonding or similar techniques. The mesh should preferably not be strongly cured (for example, by water entanglement, heat Or acoustic bonding or similar method X) but can be strongly cured if necessary. 'The fiber filter layer (or layers) may have a total basis weight ranging from 10 to 400 g / m², preferably from 20 to 150 g / m² for the purpose of filtration. The gas velocity of the filter layer (or layers) at 9 8 4 m / min has a combined total pressure drop of less than 10 mm water column, preferably less than 6 mm water column. The pressure drop of the filter layer will usually be at least 丨 mm water ^ -8-The paper size is suitable for the national standard (CNS) A4 specification (210χ ^ ϋ --- ---- J ------- --- ~; outfit ------ ^ order ------- j- j (please read the precautions on the back before filling this page) Employee consumption cooperation of the Central Bureau of Standards of the Ministry of Economic Affairs Description of the invention (6) Figure: A device configuration for carrying out the manufacturing method of the present invention. Ii .: 『= Guangzhou is the net forming machine, for example, a kind of combing machine or other 罔 forming device) supply-type not Weave off the net layer 1 (). In addition, the second roller can release a layer of the second net layer and the cake is joined to the net 10. This allows the base weight to be selected with greater flexibility. The Μ, 哉 口. The support 11 is fed from the supply drum 4 onto the fiber web layer 10. However, the fabric support is said to be fed upstream of the supply roller so that the fiber web layer 10 is placed on the fabric support 111 or between two fabric support layers u. A second supply drum 2 'may be used so that the fabric supports u which is an intermediate layer between two outer nonwoven web layers. This is shown in Figure 丨-a second supply roller is represented by substantially the same numbers (10, and 2 ·). Similarly, a second fiber filter layer can be released from an adjacent supply roller and merged into the mesh 10 to allow adjustment of the reference weight. The two fiber filter layers 10 and 10 | may have different reference weights. . Then feed the fiber filter layer 10 (or multiple layers) and the fabric support ii to the needling station 5, where the filter layer 10 (or multiple layers) is connected to the fabric support by needle punching Load 1 1 to form the filter medium 12. These needles should be the top filter layer before penetrating into the fabric support layer to laterally replace the fiber firmly into the fabric support, and may rise to a layer covering the fabric support, and promote the fiber and the fabric Engage and mesh with the fibers of the bottom filter layer 10 '. The needles can be arranged to penetrate the filter media 12 composite per square centimeter from between about 10 to 300 pierce. A higher needling density tends to make the filter media 12 tight. Acupuncture should be less than 7 5 per square centimeter. Then collect the acupuncture and combined composite filter media 12 on the rolling drum 6 for subsequent conversion to individual -9 through the use of a conventional technical cover.- This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210x297 gong) 1.- ------- I ·: installed ------, ordered -------- ^ (please read the precautions on the back before filling out this page) Office staff consumer cooperatives print these Yunnets can be recharged with the US Patent 3 (), 782 and 3 丨 285 = the preferred specific system of charging. The electret fiber that forms this filter is formed by a thin film charged with static electricity (for example, by a corona discharge electrode). I has been fibrillated to provide a secret contact. The fiber of this mesh can be cut in its cross section. However, the above-mentioned invention is formed by the non-electric method of charging, such as the description of the second: dielectric dielectric thermoplastic polymer which can be charged by the person to form the electret. Suitable materials include polyhydrocarbons, such as polypropylene, linear low-density (4 A) gas ethylene, polytrifluoroethylene gas, poly (A-戍 晞) or poly gas B #; polyaromatic rare polymer Such as poly 3 == copolymers and blends. The preferred one is that it does not contain branched chain I; :::: Object: the preferred one is poly — poly (4_ 甲 _ / 边 如) Wu Guo 4,789,504 revealed _ a kind of fatty acid gold Wu Guozhuan 4,456,648 revealed particulate matter: 'or Wu Jue patent ί® ^ white I agent (for example, teach or ultraviolet ray agent), filler, cross-linking ... The electret is charged to contain fleas. It is necessary to blend the film with a film or a fiber polymer or copolymer. <The adverse effect is extremely small, and it can be combined with other porous layers, such as woven or non-woven, such as reinforcing branches. The carrier fabric (for example, "species" is connected to the filter layer "covering net, etc. However, these other layers must be ^ layer" The total pressure drop of the filter can be adversely affected: the material can not be borrowed from the Danta layer. Greek patent Levi Λβ »· Qi Fang-10-

1 .--- ^ ----- 1. Installation ------- order ------ J ,, Λ (please read the precautions on the back before filling this page) 311096 A7 ______B7 5. Description of the invention (8) A method such as lamination to the filter by means of adhesives, point bonding, etc. The filter medium of the present invention can be used in any conventional air filter, but it is particularly suitable for air filters that filter large volumes of air, such as furnace filters, automobile cabins, and room air cleaners. The filter medium of the present invention can be incorporated into the filter in a flat or folded configuration in any conventional manner. Description of Examples The physical properties of the various supporting fabrics used in these examples are listed in Table I and the porosity characteristics are listed in Table II. In these tables, Sample 8 is topped HS-9 107, B is Claf ™ 2S-150 1, C is Claf ™ HS-170 1 and D is Lutrasil ™ 10 g / m². LutrasilTM fabrics are obtained from Firrna Karl Freudenberg of Kaiserbautern, Germany, and (^^ fabrics are obtained from 8111〇 (; 〇 川 丨 _) ^ and all are plated with aluminum. These Claf ™ fabrics are lower than this product The initial pressure drop 'is even true for ClafTM fabrics with significantly higher reference weights. Printed by the Consumer Standards Cooperative Staff of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling out this page) In Table I, the benchmarks obtained The weight is the average number of five samples. To determine the thickness of the fabric is to stack the five samples together and use the "parallel plate thickness tester" (&quot; parallel Plate Thickness Tester &quot;) to use. 1 The thickness of the g / cm pressure gauge and the resulting value divided by 5. To determine the pressure drop, the five samples were combined by AFT Model 8110 (obtained from TSI, Inc., Minneapolis, Minnesota) automatic filter test machine, The volume flow rate of 100 liters / minute passes through the sample area of 9 65 square centimeters to produce a surface velocity measurement of 9 8.4 meters / minute for the combined sample.

Instron Model 1122 uses a sample size of 2.54 cm X 17.8 cm to measure the tensile strength at a crosshead rate of 288 cm / min. -11-The size of this paper is leisurely Chinese National Standard (CNS) A4 (210 X 297 mm) A7 B7 printed by the Employee Consumer Cooperative of the Central Prototype Bureau of the Ministry of Economic Affairs V. Description of invention (9) Then use a large lens The Leica Quantainet (^ _57〇 Image Analyzer (Leica Quantamet Q-570 lmage AnalyZer) analysis fabric (A to C) net. Use Q-570 and a developing microscope and incident light (illumination from an angle) to analyze the fabric D. Use transmitted light on the fabric samples (a to c) to emphasize the opening area. Scan the sample area of 1 98 6 mm 2 for the Claf ™ fabric object, and view the 29 24 mm 2 for Lutrasil ™ * material Area. Each sample is scanned or viewed in four areas or three samples are tested for each supported fabric. Q _ 5 7 0 The camera only measures the open area of the focus and is therefore on the same measurement plane. For each sample (A to D), q _ 5 7 〇 directly measure the individual opening area or the number of openings, the length, width and periphery of the opening, and the area of the opening. Calculate from the value of the meter-the average of the openings Area, average aspect ratio and effective circle diameter. Table II The average number of openings of each of the fabrics A to e and the average area of individual openings (calculated value) and average length, average width, average periphery, average aspect ratio (calculated value) and average effective circle diameter (ECD) (calculated Value). C1 a fTM fabrics A to C and E (E is unplated metal C) have porosity characteristics which provide more than 300 times the opening area of 1 ^ 1 ^^ 511 top fabric (0). There is still an "effective circle area, which is calculated from the area characteristics of each open area, and also shows that the effective circle diameter of the Claf ™ fabric is 14 to 19 times larger than that of the Lutrasil ™ fabric. Example 1 According to US Patent 5,230,800 Method to prepare a fabric-supported nonwoven electret charged fiber filter media (Comparative Example 1 D). It uses a 10 g / m² spun-bonded fabric Lutrasil ™ (fabric D) (from Germany-12) -This paper scale is applicable to China National Standard (CNS) A4 specification (210X297mm) .------------ "-installation ------ ^ order ------- (please first Read the precautions on the back and fill in this page) A7 B7 printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economy V. Description of the invention (10)

Made by Karl Freudenberg of Kaiserlautern). The filter contract for this media is 35 g / m² of fibrillated thin film electret fibers made according to US reissue patents 3 0, 7 8 2 and 3 1, 2 8 5. In addition, three identical filters were made, except that they used clafTM fabric (made by Amoco / Nisseke and plated with aluminum) (fabrics A to C and Examples 1 A to 1C). These fabrics were needle-punched and combined with a nominal 35 g / m2 of the above-mentioned fibrillated film electret fiber reticulated web, as described for those who used LutrasilTM fabric to prepare the filter media as described above. Filter media was taken from all samples for analysis and comparison. The results are listed in Table III. By weighing a dish with an area of 100 square centimeters, the total reference weight of each filter media is determined and converted into grams per square meter. The average reference weight of the filter part of the sample is calculated from the total reference weight of the filter media minus the weight of the fabric. Measure the pressure drop and penetration in the AFT Model 8110 test machine based on the test area of 3.8 cm in diameter, a test speed gauge at 100 liters / min (this produces a surface speed equivalent to about 9 8 _ 4 m / min or 3 〇〇η feet / minute). The challenge air contains a Na C1 aerosol. The calibration of the challenge was determined to be 14.66 mg / m3. "Through percentage, is the ratio of the concentration of Na C1 particles measured downstream and upstream of the filter multiplied by 100. Each test, or test cycle, produces a" pressure drop "and" initial through percentage, " Then, the AFT Model 8110 is continuously circulated (challenged with Naci particles of the same concentration) until a specific pressure drop is reached (12.5 mm water column). The "number of cycles" required to reach this specific pressure drop can be regarded as the filter life Period-a kind of direct indication. This pressure drop is selected as the end of the filter life (that is, the "number of cycles"), because most furnace filter manufacturers believe that the surface is 5-9 meters / minute-13- The size of this paper is applicable to the Chinese National Standard (CNS) A4 specification Ding 21〇 \ 297 (published)-Ί --------- installed --------, ordered ------ J. .vi (Please read the precautions on the back before filling in this page) 311096 A7 B7 V. Description of the invention (η) Speed through a pleated filter or 9 8.4 m / min surface speed through β | a flat filter when the pressure drops Up to 12.5mm water column, the filter needs to be replaced. The quality factor Q is based on the mathematical formula: ^ -ln (% P / 100) Q =-ΔP is defined, where% is the percentage of penetration, ΔP is the pressure drop in mm of water column, and 1 η is the natural logarithm. This value is often a positive number that increases as the penetration decreases. Conversely, when the pressure drop increases, Q decreases. Q is usually an index that has nothing to do with the reference weight. Therefore, Q can be used to compare the filtering performance of nets with different reference weights. The overall result is the average of three test samples, except for IC It is the average of the two tests. Table III shows (: 1 &amp; £ woven fabric backing filter compared with the control filter (sample 0), there is a significantly lower initial pressure drop and comparable initial Throughout the percentage. However, Claf ™ as a backing filter, based on the number of cycles of the pressure drop of 12.5 mm water column as the end of life calculation, has reached about twice the filter life. Claf ™ as a backing filter also has a High Q value. _ I —------ 1, installed ------ ^ subscribe 丨 ----- ii (please read the precautions on the back first and then fill out this page) Employee of Central Bureau of Standards, Ministry of Economic Affairs Consumer Cooperative Printed Table I Basic weight of fabrics and fabrics (g / m²) Fabric thickness (mm) Fabrics Pressure drop (mm water column) Tensile strength (kg / meter) A 35.0 0.21 .931 297.8 B 23.1 0.15 .507 196.2 C 15.9 0.12 .501 123.9 Comparative Example D 10.0 0.08 1.008 22.4 -14-This paper size is applicable to China Standard (CNS) A4 specification (210X 297mm) A7 B7

Printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs | Description of Invention (12)

Table II Fabric opening area (mm2) Length ^ (mm) Width (mm) Perimeter (mm) Aspect ratio Effective circle diameter (mm) A 1.4 1.8 0.98 4.8 2.2 1.2 ''-629 B 2.0 2.1 1.2 5.8 2.2 1.5 ~ --- 511 C 2.0 2.1 1.1 5.8 2.2 1.5 517 D 0.008 0.26 0.034 0.22 2.3 0.085 --------- 785 E 2.4 2.3 1.3 6.3 2.2 4.6 ^ ----- ~ -405

Table III Example to 12.5 mm water column cycle number Net basis weight (g / m²) Quality factor Initial pressure drop (mm water column) Initial penetration (%) 1A 23.3 30.92 0.076 4.2 73.1 1B 27.0 31.96 0.083 3.6- ------- 74.7 1C 30 31.3 0.081 3.5 ~~ ------- 76.6 Comparative Example 1D 15.7 31.90 0.060 4.8 75.2 Example Π Use the method described in Example I, using fabric A to D and 40 g / m2 of the same type of fibrillated film electret charged fiber are used to make media according to the web. Test these filter media as in Example I above. The results are listed in Table Iv *. Each test result is the average of five test samples. Table IV shows again that when using supported fabrics with a large individual opening area, at -15-this paper scale applies the Chinese National Standard (CNS) 8 4 ^^ (210X297mm) Description of Invention (η) A7 B7 Life Can be substantially increased while the pressure drop is reduced and has a high Q value to 12.5 mm t column cycle basis weight (g / m²) 2A 14.4 40.17 2B 17.8 40.10 2C 20.5] 40.16 Comparative Example 2D 11.8 39.83 Example III- --- 0.063 5.9 0.078 4.6

0.076 0.072: ----- ^ ----- "'installation-- (please read the notes on the back before filling in this page) Printed by the Employee Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs in compliance with US Patent 4,798,8 50 The procedure described makes a triboelectric electret filter. The secondary fiber is used to make this mesh: 70% by weight 4 Danny Polypropylene; and 30% by weight 5% 3 Danny Polyester, τ_Ι83 from Hoechst Celane Corp .. Attach this filter to the fabric as described below in accordance with the procedures detailed in U.S. Patent 5,23 0,800:-Attach the fabric D with 2 7.7 3 g / m² friction A charged electret mesh (Comparative Example 3D); ClafM 2S-1601 '18 g / m² fabric, attached with 28 g / m² friction to a charged electret fiber mesh (Example 3 A); And, ClafTM 2S-1601, metal-plated 18 g / m² fabric with 50,000 m² aluminum, attached with an electret fiber web frictionally charged at 29 64 g / m² (Example 3 B). Chemical fiber 75 g / 、-= 3 Quan 16- This paper scale is applicable to China National Standard (CNS) A4 specification (210X 297mm) A7 V. Invention description (14) According to the procedure detailed in Example i, the filter properties of all the formed filter media were tested. Table V lists the test results. The filter (3 A and 3B) in this example was compared to the filter (3D) in the comparative example (which used a lower basis weight but The lower average opening area of Lutrasil ™ fabric has a lower initial pressure drop to the end of life of 1 2.5 mm water column. The pressure drop has a longer life cycle and a higher total Q value. The pressure drop improvement and life improvement are higher than the example For the filter in I, this may be because the base weight and pressure drop of the supporting fabric is a higher percentage of the total weight and pressure drop of the total filter. For those skilled in this art, the present invention can obviously be modified and changed in many ways. Without departing from the scope and spirit of the present invention, and the present invention should not be limited to this. --------- f 装 ------ 定 丨 ------ ί-, Λ (Please Read the notes on the back before filling in this page) Printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs-17-

Table V Example to 12.5 mm water column cycle number Fiber basis weight (g / m²) Fabric thickness (mm) Quality factor Initial pressure drop (mm water column) Initial penetration (%) 3Α 58.7 28.75 0.12 0.028 2.6 92.9 3Β 50.7 29.64 0.12 0.028 3.1 91.5 Comparative Example 3D 23.3 27.73 0.06 0.026 4.0 90.2 This paper size is applicable to China National Standard (CNS) Α4 specification (210Χ 297 mm)

Claims (1)

Amendment of the scope of the patent application No. 2 3 5 0 (November 1985) AS B8 C8 D8 2 'Applicable patent scope-an air filter, which contains a frame and an electret fiber nonwoven filter media, The filter media contains at least one nonwoven web, which contains entangled fibers, 'at least one' of the fibers are static electret fibers', wherein the web is connected to at least one reinforcing fabric by needle punching, the reinforcing fabric There are divided opening areas of JL, wherein the average opening area has a cross-sectional area of at least 0_25 square mm and the reinforcement fabric has a total pressure drop of less than 2.0 mm water column at 984 m / min. Untwisted way night stretches from one side of the fabric to the opposite side, a method for forming an electret nonwoven filter, which includes the following steps: a) providing at least one nonwoven filter; b) connecting the at least one Filter to a kind of reinforcing fabric, the reinforcing fabric w has a separate opening area, wherein the average cross-sectional area of the opening area in the plane of the filter is at least 0.25 square mm and the fabric is at 98.4 m / min Less than 丨 5 PCT total pressure drop of the water column; E) needling at least one filter and a filter to form a reinforcing fabric; and d) the; consider some of the fibers of the web to provide an electret charge. f According to the method of item 2 of the patent application scope, the electret lotor fiber of the filter is formed by fibrillating a static-charged film. According to the method of claim 2 of the patent application scope, wherein the electret electret fiber is charged by corona discharge. ,, the method of claim 3, wherein the electret electret fiber is charged in the filter. (2i〇X297 Co-Director) I. —Installation: —Finish (please read the notes on the back and then fill in this page) Employee Consumer Cooperation Printed by the Central Bureau of Samples of the Ministry of Agriculture and Economics 4. VI. Patent Application Range Δδ Β8 C8 D8 Employee consumption cooperation of the Central Bureau of Samples and Licensing of the Ministry of Economy and Economy ¾ Printing 6 · According to the method of item 2 of the patent application scope, it is charged by the frictional electricity generation method. • According to the method of the second item of the patent application scope an inner layer between the two outer filter layers 8 · According to the method of the second item of the patent application scope: The net is formed by brushing. 'According to the method in item 2 of the patent application scope, Weiyuan is a polypropylene polymer or copolymer fiber and the reinforcing fabric is a network of cross-laminated fibers. Electret fiber non-woven filter media, comprising at least one non-woven filter mesh, the filter mesh comprising entangled fibers, at least a portion of which are electrostatic electret fibers, wherein the mesh is connected to at least one reinforcement by needle punching Weave 2, the reinforcing fabric has a discrete opening area where the average opening area has a cross-sectional area of at least 0.25 square mm, and the reinforcing fabric, 8 '4 A feet / minute has a total pressure drop of less than 2.0 mm water column , Where the side opening area extends from one side of the fabric to the opposite side in a non-distorted way. According to the patent application item 10 of the electret fiber nonwoven filter media, the discrete opening area of the reinforced fabric is averaged across The area is at least 0.5 square mm. 'a Patent scope No. _ electret fiber non-woven media,' the average cross-sectional area of the open area of S reinforced weaves is at least 1 _ 0 square mm. 13_According to the Chinese Patent Application No. _, electret fiber nonwoven media, wherein the electret charged fiber, wherein the reinforcing fabric is at least one of the nonwoven, and the electret charged fiber 1 〇 --- ---- ^ --- installed '------ ~ lτ ------ line. ▲ Material (please read the precautions on the back before filling in this page).' GM-2- as B8- ___ C8 -_ ^ 8 a. The scope of applying for patents. Printed by the Central Bureau of Economics of the Ministry of Economic Affairs Employee Consumer Cooperatives. F The opening area of the children ’s reinforced fabrics has an average path length. The ratio of the average path length of five children to the average fabric thickness is 3 to 13 4 · $ According to the electret fiber non-woven media of item 12 of the patent application, the reinforced fabric in U &quot; has a tensile strength of at least 50 kg / m. According to the electret fiber nonwoven filter media in item 10 of the patent application scope, the open area of the medium and reinforced fabrics has an aspect ratio from 0 to 5 and the open area of the separate reinforced fabrics has an average approach The length is the ratio of the average length of the 16th channel to the average thickness of the fabric from 2 to 13. . The electret fiber non-woven filter media of the item, wherein the open area of the reinforcing fabrics is at least 300 micrometers equal to the ECD. The electret fiber nonwoven filter media according to item 10 of the Shenlong patent scope, wherein the reinforcing fabric has a tensile strength of at least 50 kg / m. 18. According to the electret fiber non-woven filter media in Item 1Q of the Chinese patent application, the child-reinforced fabric has a tensile strength of at least 100 kg / meter. 19. According to the scope of the patent application! "Electret fiber nonwoven filter media, where the pressure drop of the reinforced fabric is less than 1.5 mm H2O. 20. According to item 10 of the patent application scope, the electret fiber nonwoven filter media, where the child reinforces the fabric pressure The pressure drop is lower than 丨 〇mm water column. 21. According to the electret fiber non-woven media in item 1 () of the patent application, the pressure drop of the reinforced fabric is less than W% of the pressure drop of the filter 〇22. According to: Please request the electret fiber nonwoven filter media in item 10 of the patent scope, wherein the reinforcing fabric is formed of thermoplastic polymer fiber. 210X297mm (please read the precautions on the back before filling in this 筲) Install ·, va line • Please specialize in the third electoral series of the residual electic media:: Fine-fibrillation-a film-forming polymer with an electrostatic film to form the resident fibers. $ According to the application of special sibling fiber materials, media, and middle school electret fibers are polypropylene polymers or copolymers. The electret fiber nonwoven filter media according to item 10 of the patent application scope, where the child-reinforced fabric is one of the intermediate layers between the two outer layers of the nonwoven filter. 2 6. The electret fiber nonwoven filter media according to item 10 of the patent application scope, wherein at least one of the nonwoven webs is a combed brush web. 2 7 According to the electret fiber item 10 of the patent application scope, at least one of the non-woven screens is a melt blown screen. According to the electoral fiber nonwoven filter media of item 10 of the patent application scope, at least one of the nonwoven filter screens has a total basis weight of less than 120 g / m². The electret fiber non-woven media according to item 10 of the patent application park also includes an outer reinforcement layer laminated to an outer surface of the filter. 24 25 28 29 .--.--- installed ------:-order ------ line '1: (Please read the notes on the back before filling out this page) Staff of Central Bureau of Standards, Ministry of Economic Affairs The size of the paper printed by the consumer cooperative is applicable to the Hu Family Standard (CNS) 6.4 specifications (21 (}) &lt; 297g)