JPH05504717A - New filter material for surgical and clean room masks - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] New filter material for surgical and clean room masks absorption public The present invention provides novel filaments for use in surgical masks and clean room masks. It concerns Luther wood. This new filter material is a protective non-woven fabric or Laminate of non-woven fabric and highly permeable oriented polytetrafluoroethylene laminate Microporous expanded polytetrafluorocarbon material, which does not require a support structure, is used only at the periphery of the mask. It uses an ethylene filter membrane bonded. This filter material is , has a structure with high filtration capacity and low airflow resistance. Also containing the laminate This filter material produces less lint.

Distortion of favor Historically, respirators and improvised masks have been used to protect against toxic or unpleasant dust, It has been worn to prevent inhalation of smoke or germs. Surgical masks are used in the operating room. This is to protect the Fool from contamination by staff and others. Semiconductors and computers Clean in the computer industry and in industries related to materials for use in outer space. ・As the workload in the room increases, or acquired immunodeficiency syndrome With the advent of ATDS, the performance of ready-to-use masks has become more important. Ta. In industries such as semiconductors and computers, extremely fine patterns on semiconductor chips are used. It is necessary to prevent contamination of the surfaces of the Ru. In addition, in the field of medicine/surgery, patients suffering from AIDS or hepatitis are There is a growing need to prevent medical staff from coming into contact with the fluid. But Izu In both cases, masks that have higher filtration performance and are easier to wear are being worn. nine Additionally, wearing a mask can generate lint when used in a lean room. There has to be no. In either case, masks are recommended for hygiene and cost reasons. It is desirable that it be disposable.

As clean rooms improve, class 100 and class 10 clean ・The room is now used instead of the class 1000 clean room. I came. A Class I clean room is also currently in use. number of this class The smaller the value, the smaller the allowable maximum particle size as well as the allowable total number of particles. semiconductor industry In the industry, the level of cleanliness is directly correlated to the amount of products that pass the standards.

As you might imagine, a very clean facility would be able to handle such low particle counts. using air filters, air exchangers, laminar flow hoods, and construction materials that allow Designed.

However, human operators are also required to be within this level. However, it is clear that the human body is a major source of particle pollution. , skin particles, clothing lint, and scattered dust adhering to clothing are all main causes. It is an important pollutant. These substances are used in lint-free clothing. The development of protective clothing such as suits), headgear, boots, and howe covers has improved the Now you can troll. An unsolved problem is exhaled air contamination. It is dyed.

Expired air contamination is caused by coughing or sneezing and by residue in the smoker's mouth or trachea. Staining occurs. A smoker's breath contains particles with a particle size of 0.2 to 0.4 microns even after 10 minutes of smoking. It contains 30 to 500 times more particles than non-smokers. Usually non-smokers are Most particles are not exhaled (Hoenig, Daniels, J, o fEnvironmental 5sciences, 4B-52, March /April 1984).

In addition, clean room masks must not be lint-producing; The biggest drawback of many currently available masks is the generation of lint.

Clean room operators wear masks at all times, so traditional masks A mask that is easy to wear across multiple social settings is highly desired.

Medical/surgical masks have high aerosol and bacterial filtration capabilities for safety. It is also required to have low air permeation resistance so that it is easy to breathe. It is.

Air passage resistance is measured according to US military standard MIL-M-36954C1 test method 4.4.1.2. Measure based on. This transmission resistance is indicated by the value "delta P". "delta "P" is the amount of air that passes through a certain part of the filter when a certain amount of air passes through a specific part of the filter. This refers to the pressure difference that occurs in the tar material. Delta P stops the airflow that has passed through the filter. It is converted into millimeters of water column corresponding to the pressure of .

The delta P value is a measurement of the airflow passing through the filter, so it is It also refers to the wearability of the mask that you feel when breathing through a ready-made mask made of Luther wood. Correlate. The higher the delta P value, the more careful the person wearing the face mask. I feel the badness of the land.

In order to breathe easily, a low delta P value is essential. On the other hand, the filter The smaller the pores, the higher the filtration capacity, but the delta P value also tends to increase.

The aim of the invention is to solve these problems.

The main bean is angry! Star R place The present invention provides microporous permeable filter membranes, preferably microporous expanded polytetrafluor. The oleoethylene membrane can be bonded to 1) a protective fabric, or 2) a microporous ductile material with a high degree of permeability to the fabric. A ready-to-use mask can be made by combining a protective laminate with expanded polytetrafluoroethylene. A filter with low airflow resistance, that is, a low delta P value, and very high filtration performance. The aim is to provide filter materials with improved breathability. Ru. Filter membranes that do not significantly increase the delta P value by selecting membranes with several types of structures By choosing the method of bonding the protective layer to the filtration capability has become possible. Means for combining the protective fabric layer or laminate with the filter membrane However, without using conventional AM technology, the peripheral part of a filter mask-sized sample can be It is desirable to combine only with As a result, the increase in the overall delta P value is minimized. A filter membrane that does not require a support structure was obtained. To protect the filter membrane. Microporous expanded polytetrafluoroethylene membrane with non-woven fabric and high permeability When using laminates with porous oriented polytetra, the laminate has a high degree of permeability. The fluoroethylene moiety is selected from PTFE. PTFE has high transparency, so , when used in a surgical mask, the requirement of ease of donning is met. Advanced transparency Porous expanded polytetrafluoroethylene with permeability is placed on both surfaces of the composite. Both laminates are made of microporous expanded polytetrafluoroethylene membrane for filtration that does not require a support structure. By placing it inside the lint, the delta P value is small and the lint is not generated. A highly useful complex is obtained, suitable for use in a room.

figure ff hat' sucking FIG. 1 is a cross-sectional view of an embodiment of the invention. Laminated composite (20) requires no support structure microporous expanded polytetrafluoroethylene filter membrane (1) and two layers of cloth ( 2) by sewing, welding, gluing, or melt-bonding (3) around the filter material. It was attached by

FIG. 2 shows a second embodiment of the present invention, in which a microporous expanded polytetrafiltrate without a support structure is required. Two layers of fluoroethylene filter membrane (5) are connected to two outer layers of cloth (6) and the surrounding area. The edges (7) are fused and bonded to form a composite (21).

FIG. 3 shows another embodiment of the present invention, in which microporous expanded polytetra without a support structure is required. The fluoroethylene filter membrane (8) is porous with a very high degree of permeability. Two layers of a laminate (9) consisting of an expanded PTFE membrane (10) and a nonwoven fabric (11), The fabric surface is bonded in contact with the membrane (8). The laminated composite (22) is sewn The periphery is connected by 1 m of 7 layers of eyes (12).

FIG. 4 shows another embodiment of the present invention, in which microporous expanded polytetrafluoroethylene The filter membrane (13) is made of a non-woven fabric (15) and a highly permeable elastomer. Two layers of a laminate (14) consisting of a stretched polytetrafluoroethylene membrane (16) and a core In one layer of the laminate that is in contact with the membrane (13), the nonwoven fabric surface is in contact with one side of the core membrane, In another layer, a microporous expanded polytetrafluoroethylene layer also forms the core membrane (13). It is joined so that it touches the other side. These layers include the periphery (17) and At point (18), they are joined by sewing, welding, gluing, or fusion bonding. , forming a complex (23).

Main plate 5 Old Fungsei 5 plates The balance between wearability and delta P is determined by the particle removal effectiveness of the filter material. This balance is based on particles whose size is on the sub-micron level. The novel filter of the present invention is significantly related to the efficiency of removing aerosols and bacteria. - materials, it is possible to change this balance as required, which means that efficiency and The wearability can be changed as necessary.

The evaluation of surgical masks is determined by the U.S. military standard MIL-M-36954C. The defined standard is the removal of a minimum of 95% of the number of bacteria tested, i.e. the standard 4.4.1. 1.1. A bacterial filtration rate of 95% or higher as determined by the listed test method. That is true. In addition to removing particles, it also removes liquids such as splattered blood and other body fluids. There must be.

These clearly defined standards for filter materials for clean rooms are However, to determine the effectiveness of particle filter materials at the micron level and above, Using aerosols of sodium chloride at sub-chlorine levels, particles in this range of The filterability of the particles was tested. In addition, yarn N (lint) generation test (Helmke Draer lint generation test) to determine which composite structure produces the least lint. Ta. The development of filter material for masks was conducted by Il, L, Gore and As5. ociates, Elkton.

MD, delta P value months of manufacture, frequency range from 34 HzO to 3.32K H20 Should I choose a microporous expanded polytetrafluoroethylene membrane as the filter membrane? It started. The bacterial filtration capacity of the membrane itself is high, usually well over 90%. deer However, using only microporous expanded polytetrafluoroethylene membranes is extremely thin. Since it is a membrane, it is easy to break, and it is difficult to handle because it lacks thickness, so it is not practical. It's not useful. Therefore, a protective and supporting structure for the membrane is necessary; Delta P must not increase significantly.

Continuous filament polypropylene, polyester or polyester with open structure The use of amide nonwoven fabrics allows microporous oriented polytetra without excessively increasing delta P. It has been found to be effective in protecting fluoroethylene filtration membranes. 1 square With a weight per yard of 1.0 ounces to 1.5 ounces, Hanes Conv It is released by esting Company, Conovec, and NC. , "Elite 21 White (Elite 20 White) J and Also known as "Elite 45 White J" Continuous filament polypropylene nonwovens are preferred.

Hydrophobic fabrics such as polypropylene have the advantage of being waterproof, meaning they do not get wet during use. It has the advantage of being thermoplastic. Thermoplastic and hydrophobic fabrics Porous expanded polytetrafluoroethylene filter membrane and heat bonded or welded It can be glued.

The delta P value of this complex should be approximately 5 to 6 Hz or less, preferably 4 Hz or less. Conventional lamination to bond the filter membrane to the outer fabric layer The law must be avoided. When using traditional thermal bonding or gluing methods, Delta P For example, if a filter membrane with a delta Pgi of 1.9 L O is Bonded with polypropylene non-woven fabric with a TaP value of 0.18■H,O by continuous thermal bonding. As a result, a laminate having a delta P value of 3.3 m)lzo was obtained. Same microporous spread Stretched polytetrafluoroethylene filtration membrane with two layers of the same non-woven fabric and &1 or heat Bonded around a mask-sized sample measuring 4 inches by gluing. The delta P value is 2.4■H,O, which is the delta P value of both components. is only slightly larger than the theoretical value of the delta P value obtained by adding there were. Therefore, the characteristics of the present invention are that the protective cloth and the laminate can be used in a mask-sized sample. This is a structure that does not require a support structure for the filter membrane, which is bonded only at the periphery. child Due to the structure, the filter material of the present invention has high filterability and very good wearability. Gender has become one.

Filter membranes that do not require support structures and continuous filament nonwoven fabrics, or A laminate of expanded polytetrafluoroethylene with excellent permeability is sewn and heat bonded. Bonding at the periphery of a mask-sized sample by adhesion, gluing, or fusion Composites manufactured by the 0-wire method that are capable of holding the mask in place Elastic band to make it sturdy enough to support the attachment of the band. bind the complex One method for bonding is thermal bonding, which utilizes the thermoplastic properties of nonwoven fabrics. desirable.

A U.S. patent is needed to provide lint-free properties to clean room masks. Highly transparent, as described in Application No. 305.839 Laminated layer combining stretched polytetrafluoroethylene membrane and continuous filament nonwoven fabric The body has been used. The delta P value of these membranes themselves is between 0.45 and 0.6 inches. H, O level, "Ililite 45 White" ite) The delta P value of the laminate with J nonwoven polypropylene is l, 5 inches H2 It was less than 0. Although the filtration performance of these laminates was low, their original use Back of entrance 1 The aim is to prevent the generation of lint.

A filter composition with low lint generation is composed of layers of the laminate, and the laminate has a high degree of The permeable expanded polytetrafluoroethylene layer faces the outside and the inside of the laminate. Polypropylene fabric surface, microporous oriented polytetrafluoroethylene that requires no support structure adjacent to one side of the filter membrane. On the other side of the filter membrane, Another set of similar laminates is provided with the polypropylene side of the laminate adjacent to the filter membrane. The highly permeable expanded polytetrafluoroethylene layer of the laminate is in contact with the outer layer of the laminate. It is placed facing the side.

For composites used in surgical masks, these composites for clean room Heat bond or weld layers of the body mask large sample along the sample periphery. Combine by.

Surgical and clean room filter materials are manufactured according to the above principles and are were tested for bacterial filtration capacity and delta P. The results are shown in Table 1.

All of the samples tested were made of various filter materials according to US military standards (same as above). Bacterial filtration ability and delta P value sample complex ai [l Bacterial filtration ability delta P value, b Structure Composition (%) (b) mmHz.

A, 1/2/1 Heat bonded only at the end 99.9111 1.85B, 1/2 /3 Same as above 99.95 3.0C, 1/4/1 Same as above 99.95 2.24 D, 1/4/3 Same as above 99.99 2.98E, 3/2/3 Same as above 99 ．． 99 3.56a, material list 1. 1.0 oz continuous filament polypropylene nonwoven fabric.

Z microporous stretched PTFE membrane, delta P value is 1.51sH, O03, 1.5 oz. Continuous filament polypropylene nonwovens and microporous oriented polytetrafluoroe It is a laminate of tyrene film (delta P value is 0.74 mmHz O), and the film is placed on the outside.

4. Microporous expanded polytetrafluoroethylene (air flow resistance is 1.90 m*Hz O ).

b. Regarding bacterial filtration capacity and delta P, the US military standard MIL-M-36954C is used. The test was conducted according to the following.

C. Virus filtration ability was tested according to the modified method of b.

It easily reaches the bacterial filtration capacity I$ (95% or more) determined by The deviation was also less than 4 mmH,O.

Tests were then conducted using sodium chloride aerosol. These test results are shown in Table 2.

As shown in the results in Table 2, the filtration ability of microporous stretched polyamides with different permeability By choosing a tetrafluoroethylene filtration membrane, the outer It can be adjusted to some extent depending on the protective cloth.

The lint generation test of the sample was conducted using the Helmke Drum (Helmke Dru layer) test. I went further. The results are shown in Table 3.

Table 2 Particle size (b) Sample configuration (a) 0.10-0.12 0.25-0.35 0.45- 0.60A, 1/2/1 71.3 82.2 92.7B, l/2/3 72.9 92.7 97.8C, 1/4/1 80.0 87.5 96.3 D, 1/4/3 85.8 94.5 99. OE, 3/2/3 84.9 95.3 99.3a, material list 1.1.0 oz continuous filament polypropylene nonwoven fabric.

2. Microporous expanded PTFE membrane, delta P value is 1.51mH, O03, 1.5 oz. Continuous filament polypropylene nonwoven and microporous expanded polytetrafluoro It is a laminate of ethylene membranes (delta P value is 0.74 mHz O), and the membrane is placed on the outside.

4. Microporous expanded polytetrafluoroethylene (delta P value is 1.9 Qa+) ( z　o).

b. Sodium chloride aerosol filtration capacity as described in the experimental section.

Table 3 Particles 0.3 u 7 minutes Sample configuration (a) E 3/2/3 42.3 a. Material list 1. 1.0 oz continuous filament polypropylene nonwoven fabric.

λ Microporous expanded PTFE membrane, delta P value is 1.51 degrees H20° 3.1.5 oz. Continuous filament polypropylene nonwoven and microporous expanded polytetrafluoro Laminated body of ethylene membrane (Delta P value is 0.74■H20), the membrane is placed on the outside.

4. Microporous expanded polytetrafluoroethylene (delta P value is 1.90■H, O).

As shown in Table 3, porous stretched polyamides with a high degree of permeability, such as sample E. Highly porous membrane by placing a tetrafluoroethylene layer on the outside Compared to the comparative complex (A), which does not receive the protective effect of Ta.

Aerosol °P Regarding the effectiveness of filter media, the US military standard MIL-M-36954C5ection 4.4.1. The test was conducted as described in Method I. The test procedure is described below. Ru.

virus aerosol The above details were followed except that the agar plates contained host bacteria for the specific test virus. Tests similar to those for bacterial filtration were conducted6 The viruses commonly used are T7 or Ph1. -X-174.

Ge J beg 4 shaku Regarding Delta P, which is breathable, it meets US military standards MIL-M~36954C5ect. ion 4.4.1.2. The test was conducted using the method described in .

4, 4.1.2. Air is passed through the measured surface area at a specified air exchange rate. Measure the air exchange pressure of various materials using a device that measures the pressure difference required to (See Figure 5). To measure the pressure difference, use a manometer (ml or ml) filled with water. and m2). To measure air flow, use the Roger Guilmont Instrument. Roger Gilmont Instrument (R,G , 1. ) or a flowmeter with equivalent accuracy.

To adjust the flow rate, use an electric vacuum pump to pump air through the device using a needle valve. aspirate. Pour the test substance vertically into an orifice with a diameter of 2.5CI+, fixed in line with the airflow and so as to block the airflow. operate the pump , adjust the air flow rate to 8 liters per minute. Manometer values m1 and m Read and record 2. Perform this operation at five different locations on the mask and average the measured values. Melt. Air exchange pressure is calculated according to the following formula.

In the formula, ¥1 is the measurement taken using manometer 1 at 5 locations in the low pressure area of the test substance. It represents the average value of the values (Kaku H20).

Xst is the measured value obtained using a manometer at 5 points in the high pressure part of the test substance. Represents the average value (mHz).

4.9 is the surface area (C1l'') of the test substance.

Delta P is the atmospheric pressure difference around the test substance ICI, expressed in mH,0. .

Helmke Dome in Institute of Environmental Science Recommended Standards (IES-RP-CC-003-87-T, 1989) A help for measuring the amount of separable particles with a particle size of 0.3 μm described in October). The Muke Drum test is described below.

Hysodium aerosolpa Similar to the device described above, the filter material is tightly sealed and the air velocity passing through the sample is Sodium chloride aerosol filtration capacity using equipment set at 3.2 m/min. was measured. Thoroughly mix the sodium chloride aerosol in the air stream at the same flow rate, and is passed through the sample of air filter material. A small piece of the sample is exposed to the test air stream. The sample was taken from both airflow and throughflow to determine the exact number of sodium chloride particles in each airflow. Place on a dual laser particle counter to measure. Penetration value is the narrow The number of particles with a different particle size range is compared with the number of particles with the same particle size range in the test air stream. It is just a comparative value. The filtration value (%) is 100-(100x penetration particle rate) Ru.

Main contract It is a filter material for surgical and clean room masks. ) Combines a nonwoven fabric with a highly permeable stretched polytetrafluoroethylene membrane It consists of a protective laminate and an IN or two or more layers of microporous filter membrane.

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Claims (11)

[Claims] 1. stomach. Protective non-woven fabric or B. Combines a nonwoven fabric with a highly permeable stretched polytetrafluoroethylene membrane. The protective laminate is transformed into a microporous filter membrane that does not require one or more layers of support structure. Flaps for use in surgical and clean room masks consisting of bonded composites. A protective non-woven fabric or laminate in both cases A and B. The nonwoven fabric surface of is in contact with both sides of the filter membrane, and the bacterial filtration capacity of the composite is 9. 5% or more, and the filter belly is only in the periphery of the filter material or Filters for use in surgical and clean room masks, combined with filters -Material. 2. The filter according to claim 1, wherein the composition has a delta P value of 5 mm or less. -Material. 3. The filter according to claim 1, wherein the composition has an outside del P value of 4 mm or less. -Material. 4. The filter membrane has a delta P value of 1.34 mmH2O and 3.32 mmH2O. The polytetrafluoroethylene according to claim 1 is a microporous expanded polytetrafluoroethylene that is between filter material. 5. The fabric is a continuous filament polyamide, polyester or polyolefin The filter material according to claim 1, which is a nonwoven fabric of. 6. Claim 1, wherein the fabric is a continuous filament polypropylene nonwoven fabric. Filter material included. 7. The protective laminate consists of a highly permeable oriented polytetrafluoroethylene membrane. Consisting of bonded continuous filament polypropylene nonwovens, the entire composite provides support Structure-free microporous expanded polytetrafluoroethylene filter membrane and protective laminate A laminate in which the body and the laminate are combined such that both cloth surfaces of the laminate are in contact with one surface of the outer membrane of the fill. The filter material according to claim 1, which consists of two layers. 8. Continuous filament non-woven protective fabric is made of slightly oriented polytetrafluoroethylene fiber. compared to a similar composite consisting of two layers bonded to one side of the Luther membrane. The filter material according to claim 5, wherein the amount of lint generated by the filter material is 35% or less. . 9. 9. The filter according to claim 8, wherein the peripheral portions are joined by sewing. Material. 10. 9. The film according to claim 8, wherein the peripheral portion is bonded by an adhesive. tar material. 11. Claim 8, wherein the peripheral portions are joined by thermal bonding or welding. Filter material listed.