WO2006044018A1 - Couche filtrante a additifs d'amelioration et de stabilisation de charge - Google Patents

Couche filtrante a additifs d'amelioration et de stabilisation de charge Download PDF

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Publication number
WO2006044018A1
WO2006044018A1 PCT/US2005/029030 US2005029030W WO2006044018A1 WO 2006044018 A1 WO2006044018 A1 WO 2006044018A1 US 2005029030 W US2005029030 W US 2005029030W WO 2006044018 A1 WO2006044018 A1 WO 2006044018A1
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WO
WIPO (PCT)
Prior art keywords
fatty acid
filter media
web
weight
melt processable
Prior art date
Application number
PCT/US2005/029030
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English (en)
Inventor
Stephen T. Cox
Original Assignee
Hollingsworth & Vose Company
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Publication of WO2006044018A1 publication Critical patent/WO2006044018A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/68—Melt-blown nonwoven fabric
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/69—Autogenously bonded nonwoven fabric
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/696—Including strand or fiber material which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous compositions, water solubility, heat shrinkability, etc.]

Definitions

  • the present invention relates to electret filter media having an increased level of electrostatic charge that is substantially maintained in the presence of heat.
  • Electret filter media have long been used in many filtration applications.
  • Electret filter media are those that include a dielectric insulating polymer web that is treated to possess substantially permanent spatially oriented, opposite charge pairs or dipoles.
  • common polymer webs used for electret filter media are polypropylene, polyethylene, polyester, polyamide, polyvinyl chloride, and polymethyl methylacrylate.
  • Conventional filter media are substantially lacking in electrostatic charge and rely upon impingement, impaction and diffusion for filter performance.
  • Electret filter materials offer improved filtering performance over conventional filter materials. The presence of oriented dipoles in the electret filter media is believed to enhance filter performance by allowing the filter media to attract and retain charged and uncharged particles to be filtered.
  • Electret filter materials are made by a variety of known techniques.
  • One technique for manufacturing electret filter media involves extruding a polymer, typically having a high melt flow index, through a die having a linear array of orifices.
  • An air knife is used to attenuate the extruded polymer fibers by a ratio of about 300:1.
  • the attenuated fibers are then collected on a rotating drum or moving belt using a moderate vacuum.
  • the fiber web is then treated to impart on the fiber web charge pairs or dipoles.
  • the charge pairs or dipoles can be imparted to the fiber, for example, using AC and/or DC corona discharge.
  • One problem associated with electret filter material is that the charge pairs or dipoles imparted to the filter media often are not stable. In some instances, charge or its spatial orientation is lost after filtering certain contaminants for relatively short time periods. The result is a marked decrease in filter performance over a relatively short period of time (e.g., less than 20 minutes).
  • One other problem associated with electret filter material is their inability to maintain the electrostatic charge after being subjected to heat. Manufacturing standards for respiratory products, for example, often mandate that final respiratory mask be subjected to a thermal treatment process to simulate an aged phenomenon. Accordingly, there exists a need for electret filter media having an increased electrostatic charge in combination with an enhanced charge stability.
  • the present invention provides a filter media, comprising a meltblown electret polymer fiber web having a melt processable fatty acid amide present within the web and effective to enhance the level of electrostatic charge, and a melt processable fatty acid metal salt present within the web and effective to maintain the electrostatic charge when the filter media is subjected to heat.
  • the melt processable fatty acid amide is a metal stearate, for example, magnesium stearate or zinc stearate.
  • the melt processable fatty acid amide is selected from among a stearamide, ethylene bis-stearamide, and mixtures thereof.
  • the invention provides a filter media, comprising an electret web of fibers, the fibers comprising a blend of a polymer, a fatty acid amide, and a metal stearate, the fatty acid amide being present within the web at a concentration in the range of about 0.5% to 11% by weight, and the metal stearate being present within the web at a concentration in the range of about 0.1% to 20% by weight.
  • the invention provides a filter media, comprising a meltblown electret polymer fiber web having a basis weight of about 60g/m 2 and having a melt processable ethylene bis- stearamide present within the web at a concentration in the range of about 0.5% to 11% by weight, and a melt processable magnesium stearate present within the web at a concentration in the range of about 0.1% to 20% by weight.
  • the invention provides a meltblown electret web of polymer fibers, the polymers fibers comprising a polymer, about 0.5% to 11% by weight of a fatty acid amide, and about 0.1% to 20% by weight of a fatty acid metal salt, the fatty acid amide and the fatty acid metal salt being dispersed in the polymer as a melt blend additive.
  • the invention also provides a method for forming a filter media, comprising: extruding a polymer composition containing a polymer, a fatty acid amide, and a fatty acid metal salt to form a meltblown polymer fiber web; and imparting an electric charge to the meltblown polymer fiber web to form a meltblown electret polymer fiber web.
  • the method can alos include the step of subjecting the meltblown electret polymer fiber web to a heat treatment.
  • the filter media includes a melt processable charge enhancing additive, such as a fatty acid amide, and a melt processable charge stabilizing additive, such as a fatty acid metal salt.
  • the charge enhancing additive is particularly effective to increase or enhance the electrostatic charge of the filter media when a charge is imparted thereto, and the charge stabilizing additive is particularly effective to stabilize the charge such that, when the filter media is subjected to a heat treatment, the enhanced electrostatic charge is substantially maintained.
  • the filter media can be adapted for use in a variety of applications including, by way of non-limiting example, ASHRAE filters, vacuum bag filters, vacuum exhaust filters, room air cleaner filters, engine/cabin air filters, HEPA (High Efficiency Particulate Air) filters, and ULPA (Ultra Efficiency Particulate Air) filters.
  • the meltblown polymer fiber web can be formed from a variety of polymeric materials, which may vary depending on the intended use.
  • suitable polymers include polyethylene, polypropylene, polyamide, polyvinyl chloride, polymethylmethacrylate, polyester, and mixtures thereof.
  • the meltblown polymer fiber web can also include a variety of melt processable charge enhancing additives.
  • the charge enhancing additive can be, for example, a fatty acid amide that is derived from a fatty acid, which includes saturated or unsaturated straight chain carboxylic acids obtained from the hydrolysis of fats.
  • Exemplary fatty acids include lauric acid (dodecanoic acid), myristic acid (tetradecanoic acid), palmitic acid (hexadecanoic acid), stearic acid (octadecanoic acid), oleic acid ((Z)-9-octadecenoic acid), linoleic acid ((Z,Z)-9,12-octadecadienoic acid), linolenic acid ((Z,Z,Z)-9,12,15- octadecatrienoic acid) and eleostearic acid (Z,E,E)-9,11,13-octadecatrienoic acid).
  • the amides formed from the above referenced acids are primary amides which are prepared by methods well known in the art.
  • Secondary and tertiary fatty acid amides are also suitable as charge enhancing agents wherein the amide nitrogen is substituted with one or more alkyl groups.
  • Secondary and tertiary fatty acid amides can also be prepared by methods well known in the art, such as by esterification of a fatty acid followed by an amidation reaction with a suitable alkylamine.
  • the alkyl substituents on the amide nitrogen can be straight chain or branched chain alkyl groups and can have between about two and twenty carbon atoms, inclusive, preferably between about two and 14 carbon atoms, inclusive, more preferably between about two and six carbon atoms, inclusive, most preferably about two carbon atoms.
  • the fatty acid amide can be a "bis" amide wherein an alkyl chain tethers two nitrogens of two independent amide molecules.
  • alkylene bis-fatty acid amides include alkylene bis-stearamides, alkylene bis-palmitamides, alkylene bis-myristamides and alkylene bis-lauramides.
  • the alkyl chain tether includes between about 2 and 8 carbon atoms, inclusive, preferably 2 carbon atoms.
  • the alkyl chain tether can be branched or unbranched.
  • Preferred bis fatty acid amides include ethylene bis-stearamides, such as ACRA WAXTM C, available from Lonza, Inc. of Fair Lawn, N. J., and ethylene bis-palmitamides such as N,N'- ethylenebistearamide and N,N'-ethylenebispalmitamide.
  • fatty acid amides include stearamide and ethylene bis- stearamide.
  • An exemplary stearamide is commercially available as UNIWAX 1750, available from UniChema Chemicals, Inc. of Chicago, Illinois.
  • ACRA WAX® C is an ethylene bis-stearamide which is commercially available from Lonza, Inc. of Fair Lawn,
  • ACRA WAX® C contains N, N'-ethylenebissteramide (CAS No. 1 10-30-5) and N,N'-ethylenebispalmitamide (CAS No. 5518-18-3) with a mixture of C-14 to C-18 fatty acid derivatives (CAS No. 67701-02-4) with an approximate ratio of 65/35/2 (N, N'-ethylenebissteramide/N,N'-ethylenebispalmitamide/ mixture of C-14 to C-18 fatty acid derivatives) by weight.
  • the commercial product includes N,N'- ethylenebisstearamide, N,N'-ethylenebispalmitamide with C14-C18 fatty acids.
  • N,N'-ethylenebisstearamide or N,N'- ethylenebispalmitamide can be the sole charge enhancing additive.
  • the ratio of a C 14-Cl 8 fatty acid can be varied from between about 0 to 20% based on the total amount of the bisamides.
  • mixtures of N,N'-ethylenebisstearamide and N,N'-ethylenebispalmitamide which fall in the range between about 0 to 100% for each bisamide can be utilized as additive mixtures, e.g.,
  • the meltblown polymer fiber web can also include a charge stabilizing additive, such as a fatty acid metal salt, which is effective to stabilize the electrostatic charge in the web, particular when the fiber web is subjected to heat.
  • a charge stabilizing additive such as a fatty acid metal salt
  • the fatty acid portion of the fatty acid metal salt can be, for example, lauric acid, palmitic acid, stearic acid, oleic acid, etc.
  • the metal portion of the fatty acid metal salt can be, for example, magnesium, zinc, aluminum, etc.
  • the fatty acid metal salt is zinc stearate or magnesium stearate.
  • the meltblown polymer fiber web can be formed using a variety of techniques, but in one exemplary embodiment the charge enhancing additive, e.g., a fatty acid amide, and the charge stabilizing additive, e.g., a fatty acid metal salt, are mixed with a polymer resin to form a composition that is extruded into fibers to form a polymer fiber web.
  • the charge enhancing additive e.g., a fatty acid amide
  • the charge stabilizing additive e.g., a fatty acid metal salt
  • the charge enhancing additive and the charge stabilizing additive can be combined with the polymer resin in a number of ways.
  • the additives can be combined with the resin using a two screw extruder, yielding polymer pellets with a concentrated amount of each additive. These concentrated pellets, alone or combined with other polymer pellets, are then passed through an extrusion process that yields the desired polymer fiber web.
  • each additive in the composition can vary depending on the intended use of the filter media.
  • the charge enhancing additive such as a fatty acid amide
  • the charge stabilizing additive such as a fatty acid metal salt
  • the charge stabilizing additive is present within the web at a concentration in the range of about 0.1% to 20% by weight, and more preferably about 0.1% to 5% by weight, and most preferably at about 0.4% by weight.
  • the resulting polymer fiber web that is formed from extruding the composition can be comprised of fibers having a relatively broad distribution of fiber diameters.
  • the average fiber diameter can be in the range of about l ⁇ to 15 ⁇ , and more preferably about 3 ⁇ .
  • the basis weight of the polymer fiber web can also vary, especially considering the intended application. In general, higher web basis weights yield better filtration, but there exists a higher resistance, or pressure drop, across the filter barrier when the filter media has a higher basis weight. For most applications, the basis weight can be in the range of about 10g/m 2 to 200g/m 2 , and more preferably from about 20g/m 2 to 70g/m 2 .
  • Exemplary basis weights include 20g/m 2 , 40g/m 2 , and 60g/m 2 .
  • One of ordinary skill in the art can readily determine the optimal web basis weight, considering such factors as the desired filter efficiency and permissible levels of resistance.
  • the number of plies of the polymer fiber web used in any given filter application can also vary.
  • One of ordinary skill in the art can readily determine the optimal number of plies to be used.
  • an electrostatic charge can be imparted to the web to form an electret polymer fiber web.
  • a variety of techniques are well known to impart a permanent dipole to the polymer web in order to form electret filter media.
  • Charging can be effected through the use of AC and/or DC corona discharge units and combinations thereof. The particular characteristics of the discharge are determined by the shape of the electrodes, the polarity, the size of the gap, and the gas or gas mixture. In one embodiment charging can be accomplished solely through the use of an AC corona discharge unit. In another embodiment it is useful to use both
  • the polymer web is first subjected to AC corona discharge followed by one or more successive treatments by a DC corona discharge unit.
  • Charging can also be accomplished using other techniques, including friction-based charging techniques.
  • the fiber web is subjected to a discharge of between about 1 to about 30 kV(energy type, e.g., DC discharge or AC discharge)/cm, inclusive, preferably between about 10 kV/cm and about 30 kV/cm, inclusive, with a preferred range of between about 10 to about 20 kV/cm, inclusive.
  • corona unit(s), AC corona discharge unit(s) and/or DC corona discharge unit(s) can be placed above and/or below a meltblown fiber web to impart electret properties to the fiber web.
  • Configurations include placement of a neutrally grounded roll(s) on either side of the fiber web and the active electrode(s) above or below either side of the web.
  • only one type of corona discharge unit e.g., a DC or an AC corona discharge unit, is placed above, below or in an alternating arrangement above and below the fiber web.
  • alternating AC or DC corona discharge units can be used in combination.
  • the AC or DC corona discharge unit can be controlled so that only positive or negative ions are generated.
  • a permanent dipole can be imparted to the polymer fiber web as follows.
  • the web is first charged using an AC corona, followed by a charging with a series of DC corona discharge units, e.g., DC charge bars.
  • the DC corona discharge units are positioned on alternating sides of the passing fiber web and each successive DC corona discharge unit applies a charge of a different polarity, i.e., positive/negative.
  • the charge of the DC corona discharge units located above and below the non woven web alternates from positive to negative in a series of treatments, e.g., 2, 4, 6, etc.
  • the DC corona discharge units are positive or negative and do not alternate in charge.
  • the meltblown electret polymer fiber web has an increased electrostatic charge and efficiency, due to the charge enhancing additive, and the electrostatic charge is substantially maintained when the web is subjected to heat, due to the charge stabilizing additive.
  • filter performance can be evaluated based on different criteria, it is desirable that filters, or filter media, be characterized by low penetration across the filter of contaminants to be filtered. At the same time, however, there should exist a relatively low pressure drop, or resistance, across the filter.
  • alpha is the slope of log penetration versus pressure drop across the filter. Steeper slopes, or higher alpha values, are indicative of better filter performance.
  • Alpha is expressed according to the following formula
  • D P is the pressure drop across the filter.
  • DOP dioctyl phthalate
  • TSI tyl phthalate
  • the instrument measures pressure drop across filter media and the resultant penetration value on an instantaneous or "loading" basis at a flow rate less than or equal to 115 liters per minute (1 pm). Instantaneous readings are defined as 1 pressure drop/penetration measurement.
  • NaCl sodium chloride
  • TSI, Inc. equipped with a sodium chloride generator.
  • the average particle size created by the unit is 0.3 ⁇ to 0.5 ⁇ .
  • the instrument measures a pressure drop across the filter media and the resultant penetration value on an instantaneous basis at a flow rate less than or equal to 115 liters per minute (1 pm). Instantaneous readings are defined as 1 pressure drop/penetration measurement.
  • the initial alpha value i.e., the alpha value determined prior to subjecting the filter media to heat
  • the filter media is subjected to heat, e.g., a temperature of at least about 70 0 C.
  • Sample 1-1 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99% by weight of polypropylene and 1% by weight of ACRA WAXTM C.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 3.6 ⁇ , and a web basis weight of 23.69g/m 2 .
  • Sample 1-2 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99.6% by weight of polypropylene and 0.4% by weight of magnesium stearate.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 3.5 ⁇ , and a web basis weight of 22.25g/m 2 .
  • Sample 1-3 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 98.6% by weight of polypropylene, 1 % by weight of ACRA WAXTM C, and 0.4% by weight of magnesium stearate.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 8 ⁇ , and a web basis weight of 22.2g/m 2 .
  • Table 1 illustrates the penetration, the resistance at 10.5 fpm face velocity, and the alpha value of Samples 1-1, 1-2, and 1-3, as tested using a NaCl challenge, initially and after subjecting the webs to a temperature of at least about 70 0 C for about 24 hours.
  • Sample 1-3 has an initial alpha value that is significantly higher than the initial alpha value of Samples 1-1 and 1-2, each of which contain only one of the two additives.
  • Samples 1-1, 1-2, and 1-3 to heat, the alpha value of Sample 1-3 decreased from 80.6 to 65.33, however the resulting alpha value of 65.33 was still significantly higher than the resulting alpha values of Samples 1-1 and 1-2. Sample 1-3 thus showed a high initial alpha value, and the ability to maintain an acceptable alpha value.
  • Sample 2-1 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99% by weight of polypropylene and 1% by weight of ACRA WAXTM C.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 6.8 ⁇ , and a web basis weight of 60.4g/m 2 .
  • Sample 2-2 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99.6% by weight of polypropylene and 0.4% by weight of magnesium stearate.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 7.4 ⁇ , and a web basis weight of 60.04g/m 2 .
  • Sample 2-3 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 98.6% by weight of polypropylene, 1 % by weight of ACRA WAXTM C, and 0.4% by weight of magnesium stearate.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 3.4 ⁇ , and a web basis weight of 63.73 g/m 2 .
  • Table 2 illustrates the penetration, the resistance at 10.5 fpm face velocity, and the alpha value of Samples 2-1, 2-2, and 2-3, as tested using a NaCl challenge, initially and after subjecting the webs to a temperature of at least about 70°C for about 24 hours.
  • ACRA W AXTM C with a metal stearate, such as magnesium stearate, produced an electret polymer fiber web with enhanced properties.
  • Sample 2-3 has an initial alpha value that is lower than the initial alpha value of Sample 2-1, and that is not significantly higher than the initial alpha value of Sample 2-2, the alpha value was maintained, and in fact it even increased, after the Samples were subjected to heat.
  • the alpha value of Sample 2-1 decreased substantially from 63.8 to 45.02.
  • the initial alpha value of Sample 2-2 was only 37, and it decreased to 32.77 after being subjected to heat.
  • the alpha value of Sample 2-3 was initially 47.98, and it increased to 49.03 after being subjected to heat.
  • Sample 3-1 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99% by weight of polypropylene and 1% by weight of ACRA WAXTM C.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 7.8 ⁇ , and a web basis weight of 22.43g/m 2 .
  • Sample 3-2 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99.6% by weight of polypropylene and 0.4% by weight of zinc stearate.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 7.4 ⁇ , and a web basis weight of 22g/m 2 .
  • Sample 3-3 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 98.6% by weight of polypropylene, 1% by weight of ACRA WAXTM C, and 0.4% by weight of zinc stearate.
  • the meltblown electret polymer fiber web was prepared with fibers having a diameter of 3.4 ⁇ , and a web basis weight of 22.53g/m 2 .
  • Table 3 illustrates the penetration, the resistance at 10.5 fpm face velocity, and the alpha value of Samples 3-1, 3-2, and 3-3, as tested using a NaCl challenge, initially and after subjecting the webs to a temperature of at least about 7O 0 C for about 24 hours.
  • the combination of a fatty acid amide, such as ACRAW AXTM C , with a metal stearate, such as zinc stearate produced an electret polymer fiber web with enhanced properties.
  • Sample 3-3 has an initial alpha value that is significantly higher than the initial alpha value of Samples 3-1 and 3- 2, each of which contain only one of the two additives.
  • the combination of a fatty acid amide, such as ACRA WAXTM C with a metal stearate, such as zinc stearate, also produced an electret polymer fiber web having an enhanced charge stability.
  • Sample 4-1 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99% by weight of polypropylene and 1% by weight of ACRA WAXTM C. The meltblown electret polymer fiber web was prepared with fibers having a diameter of 3.6 ⁇ , and a web basis weight of 61.93g/m 2 .
  • Sample 4-2 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 99.6% by weight of polypropylene and 0.4% by weight of zinc stearate. The meltblown electret polymer fiber web was prepared with fibers having a diameter of 3.6 ⁇ , and a web basis weight of 61.4g/m 2 .
  • Sample 4-3 of a meltblown electret polymer fiber web was prepared, as previously described, from a composition containing 98.6% by weight of polypropylene,
  • meltblown electret polymer fiber web was prepared with fibers having a diameter of 8.7u, and a web basis weight of 60.9g/m 2 .
  • Table 4 illustrates the penetration, the resistance at 10.5 fpm face velocity, and the alpha value of Samples 4-1, 4-2, and 4-3, as tested using a NaCl challenge, initially and after subjecting the webs to a temperature of at least about 70°C for about 24 hours.
  • Sample 4-3 has an initial alpha value that is significantly higher than the initial alpha value of Samples 4-1 and 4-

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Materials (AREA)
  • Electrostatic Separation (AREA)

Abstract

L'invention concerne une couche filtrante à électret présentant une charge électrostatique accrue qui est sensiblement maintenue en présence de chaleur. Dans un mode de réalisation, la couche filtrante comprend un additif d'amélioration de charge pouvant être traité par fusion, tel qu'un amide d'acide gras, ainsi qu'un additif de stabilisation de charge pouvant être traité par fusion, tel qu'un sel métallique d'acide gras. L'additif d'amélioration de charge est particulièrement efficace pour augmenter ou améliorer la charge électrostatique de la couche filtrante lorsqu'une charge est appliquée sur cette dernière, et l'additif de stabilisation de charge est particulièrement efficace pour stabiliser la charge de sorte que, lorsque la couche filtrante est soumise à un traitement thermique, la charge électrostatique améliorée est sensiblement maintenue.
PCT/US2005/029030 2004-10-13 2005-08-12 Couche filtrante a additifs d'amelioration et de stabilisation de charge WO2006044018A1 (fr)

Applications Claiming Priority (2)

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US10/964,588 2004-10-13
US10/964,588 US20060079145A1 (en) 2004-10-13 2004-10-13 Filter media with charge stabilizing and enhancing additives

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WO2006044018A1 true WO2006044018A1 (fr) 2006-04-27

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US10851476B2 (en) * 2016-10-06 2020-12-01 Groz-Beckert Kg Method for producing a pleatable textile fabric with electrostatically charged fibers
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EP3666360B1 (fr) 2016-03-17 2021-09-15 Eurofilters N.V. Fibres bicomposantes comprenant des plastiques recyclés
US11896922B2 (en) 2016-03-17 2024-02-13 Eurofilters N.V. Vacuum cleaner filter bag with powdery and/or fibrous recycled material
US12016515B2 (en) 2016-03-17 2024-06-25 Eurofilters N.V. Vacuum cleaner filter bag with recycled textile materials and/or cotton liners
CN112281250A (zh) * 2020-08-17 2021-01-29 金发科技股份有限公司 一种抗菌熔喷聚酰胺复合材料及其制备方法和应用
CN112281250B (zh) * 2020-08-17 2022-01-25 金发科技股份有限公司 一种抗菌熔喷聚酰胺复合材料及其制备方法和应用
WO2022036987A1 (fr) * 2020-08-17 2022-02-24 金发科技股份有限公司 Matériau composite de polyamide soufflé à l'état fondu antimicrobien et procédé de préparation et utilisation associés

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