[go: up one dir, main page]

WO1991019034A1 - Collecteur isole servant a la production de bandes obtenues par soufflage de matiere en fusion et chargees electriquement - Google Patents

Collecteur isole servant a la production de bandes obtenues par soufflage de matiere en fusion et chargees electriquement Download PDF

Info

Publication number
WO1991019034A1
WO1991019034A1 PCT/US1991/003693 US9103693W WO9119034A1 WO 1991019034 A1 WO1991019034 A1 WO 1991019034A1 US 9103693 W US9103693 W US 9103693W WO 9119034 A1 WO9119034 A1 WO 9119034A1
Authority
WO
WIPO (PCT)
Prior art keywords
fibers
collector
die
drum
webs
Prior art date
Application number
PCT/US1991/003693
Other languages
English (en)
Inventor
Peter Moosmayer
Erwin Zurcher
William Edward Deeds
Original Assignee
Exxon Chemical Patents Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Exxon Chemical Patents Inc. filed Critical Exxon Chemical Patents Inc.
Publication of WO1991019034A1 publication Critical patent/WO1991019034A1/fr

Links

Classifications

    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
    • D04H1/56—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving in association with fibre formation, e.g. immediately following extrusion of staple fibres

Definitions

  • This invention relates generally to a process and apparatus for producing electrically charged nonwoven webs.
  • the invention relates to the manufacture of electrically charged meltblown fibrous materials in which the charge is applied to the meltblown fibers during the meltblowing process.
  • the Invention relates to electrically charging meltblown webs using an insulated collector drum.
  • Meltblowing is a one step process in which a molten thermopl stic is extruded to form a plurality of fibers. Converging sheets of high velocity air blows the fibers onto a collector surface where they are entangled and collected forming a nonwoven web. These webs, called meltblown nonwoven fabrics, have excellent properties for many uses, one of which is filtration of gases and liquids.
  • the microscopic diameters of the entangled fibers of the meltblown web are ideally suited for filtering finely divided particles out of a gaseous or liquid media. It is also known that the filtration efficiency of these nonwoven materials can be improved by applying a persistent electrostatic charge to the fibers. The charges on the web are frequently called electrets.
  • U.S. Patents which disclose nonwoven fibrous electrets include
  • Collection of the electrically charged fibers on a conductive and grounded screen can cause the fibers to lose their charge and can cause the fibers to pack more densely.
  • the apparatus and method of the present invention employs an electrically insulated collector surface which produces improved electrets since the webs hold more charges.
  • the use of insulation also appears to enhance web thickness and softness and filtration efficiency.
  • an apparatus and method for producing electrically charged meltblown webs includes an electrically insulated collector drum for collecting the meltblown fibers in forming the web.
  • the insulation may comprise a film of polyethylene, polypropylene or other substantially nonporous insulating material with suitable di ⁇ electric properties.
  • the drum may itself be made of Insulated material such as molded polyethylene, polypropylene, PVC, etc. When using film, it may be placed over a conventional collector drum and secured in place.
  • Filtration efficiency tests indicate that charged webs produced with an insulted collector drum have higher surface potentials, and lower pressure drop during filtration. Moreover, the webs collected thereon exhibit improved softness over similar webs produced with an uninsulated collector drum. In addition, filter aging tests indicate that insulated webs maintain high filtration efficiencies for long periods of time, which can be attributed to the high initial surface potential. Although the present invention is described in relation to filtration applications, it should be pointed out that electri ⁇ cally charged webs may have other applications. The filtration efficiency test described herein is an effective test for determining the charge of the webs, even if the webs are used for other applications. BRIEF DESCRIPTION OF DRAWINGS
  • Figure 1 is a schematic illustrating the main components of a meltblown line with electrostatic charging and the insulated collector drum of the present invention.
  • Figure 2 is a cross-sectional view of a meltblowing die
  • the present invention relates to an apparatus and method for collecting electrostatically charged meltblown molten or hot fibers for the production of electrically charged nonwoven webs wherein the fibers are collected on an insulated collector means (e.g. a rotating drum).
  • an insulated collector means e.g. a rotating drum.
  • the present invention is described below with reference to the apparatus and method disclosed in U.S. Patent 4,904,174.
  • the present invention may also be used with other apparatus for producing electrically charged fibrous webs such as that disclosed in U.S. Patent 4,215,682.
  • the disclosure in Patent 4,904,174 and U.S. Patent 4,215 ⁇ 682 are incorporated herein by reference.
  • a meltblowing line with electrostatic charging equipment is illustrated in Figure 1 as comprising an extruder 10 for delivering molten resin to a meltblowing die 11 which extrudes fibers into converging hot air streams forming a fiber-air stream 12.
  • the fiber-air stream 12 is sprayed onto a rotating collector drum 15 where the fibers are collected as a web.
  • the collector drum 15 is provided with electrical Insulating film 16 on the collector surface.
  • the Insulating layer 16 may be of polyethylene, polypropylene, or other nonporous or slightly porous material possessing insulating, dielectric properties (i.e. a nonconductor).
  • the electrostatically charged fibrous web 17 is withdrawn from the insulating film 16.
  • the typical meltblowing line will also Include means (heating elements 19) for heating the polymer to the meltblowing temperature and an air source connected to the die 11 through valved lines 18.
  • the die 11 includes an elongate die noseplece 22 and air knives 23 and 24 secured to the die body,
  • the nosepiece 22 has a converging section 29 of triangular cross section terminating at tip 30.
  • a central elongate passage 31 is formed 1n the nosepiece 22 and a plurality of side-by-side orifices 32 are formed in the tip 30.
  • Molten polymer is delivered to the extruder through die passage 31, and extruded as micros ized s1de-by-side fibers from the orifices 32.
  • the air knives 23 and 24 with nosepiece 22 define converging air passages 38 and 39 and an enlongate discharge opening 41.
  • Air is delivered from an air source via lines 18 through the air passages 38 and 39 and is discharged onto opposite sides of the molten fibers as converging sheets of hot air.
  • the converging sheets of hot air draw and attenuate the fibers forming a fiber and air stream 12 discharging from the die discharge 41.
  • the electrically grounded meltblowing die 11 shown 1n Figure 2 hereof 1s provided with means for applying electrostatic charges to the fibers as they discharge from the die discharge opening 41.
  • the electrostatic field is established by two electrodes 42 and 43, connected to a high voltage source, one placed ⁇ above the stream 12 and one placed below the stream 12 but equidistant from the center line 12a of the stream 12.
  • the center line 12a of the stream is the direction of orientation of the orifices 41.
  • the electrodes may be mounted on the same frame as that supporting the die 11 but have to be electrically Insulated against the die.
  • Protruding electron emitter pins 44 are secured to the air knives 23 and 24.
  • pins 44 extends along the die above the die opening 41' and a second row of pins 44 extends along the die below the opening 41.
  • the pins 44 are slanted toward the fiber-air stream and terminate in points 45.
  • the preferred dimensions a, b, c, d, and e shown in Figure 2 are as follows: DIMENSION PREFERRED RANGE (inches)
  • a high voltage source is connected to electrodes 42 and 43 (top/bottom) and the polarity 1s controlled so that the electrodes may have a +/+ charge, - /+ or -/- charge.
  • This establishes an electrostatic field between tne electrodes 42 and 43 and the ground emitters 44. This in turn creates a corona zone around the emitter tips 45 near the die discharge 41.
  • the molten or hot fibers passing through the corona zone are charged by electrons or charged particles.
  • the polarity of the electrodes is preferably +/+.
  • an Insulated, rotating collector drum 15 which includes an electrical Insulating film 16 is placed downstream of and aligned with the die discharge opening 41.
  • the fiber-air stream 12 impinges on the insulating film 16 where the fibers entangle and deposit forming a nonwoven web 17a on the film 16.
  • the insulating film 16 prevents the flow of electrical charges from the charged web 17a to the collector drum 15. It is preferred that the film be nonporous (i.e. non- permeable to air). This appears to produce a fluffy, soft web. Air flowing through the drum such as that provided by a screen tends to pack the fibers tighter.
  • the film 16 thickness may vary within wide limits but should provide the necessary insulation and be strong enough to withstand the operations without failing.
  • the film can be applied by wrapping a film panel around the drum and securing overlapped ends as by taping.
  • other web collecting means which provide the electrical insulating collector surface are possible.
  • a layer of dielectric material may be mounted around the periphery or a drum.
  • the drum itself may be composed of molded dielectric material having an impermeable collector surface.
  • the electrostatic charge equipment will be mounted on a meltblowing line.
  • the line may employ any of the thermoplastic resins capable of use in meltblowing.
  • the preferred polymer 1 polypropylene, but other polymers may be used such as low and high density polyethylene, ethylene, copolymers (including EVA copolymer), nylon, polyamide, polyesters, polystyrene, poly-4-methylpentene, polymethylmethacrylate, polytrifluorochloro- ethylene-*, polyurethanes, polycarbonates, silicones, and blends of these and other materials.
  • the meltblowing line produces fibers less than 10 microns in diameter, typically 1 to 5 microns.
  • the line is started and once steady state operation Is achieved, the electrostatic charge system may be activated.
  • a rotating collector drum 15 which includes an electrical insulating film 16 cover (preferably made of polyethylene) is positioned and aligned with the meltblown fiber- air stream. The rate of rotation is adjusted in relation to the fiber-air stream flow rate to achieve the desired web thickness.
  • Electrodes metal bars or wires Pins: 1/16 inch in diameter (steel) Resins: polypropylene (PP 3145 marketed by Exxon Chemical Co., 300MFR) Filtration Efficiency Measurements: The effect of electrostatic charge was determined by filtration tests using the following apparatus.
  • Aerosol 10% suspension of 0.8 or 0.5 micrometer latex spheres in a distilled water fog.
  • Counting optical particle counter
  • Test Conditions and Results Shown in Table I are the test conditions and comparative data for webs ("insulated webs") produced with Insulated drums (Tests 2A and 2B) and webs produced with uninsulated drums ("uninsulated webs”) (Tests 1A and IB) produced with. emitter pins 0.5 Inch 1n length.
  • Table II presents the test conditions and comparative data for insulated webs (Tests 4A and 4B) and uninsulated webs (Tests 3A and 3B) made using Simco apparatus without emitter pins.
  • the Data in Tables I and II re ⁇ present the mean of three measurements with 5 x 5 inch web samples.
  • the test results indicate that the insulated webs have significantly larger thickness than the uninsulated webs. As a result,; the insulated webs are a fluffier fabric than the uninsulated webs. The insulated webs are also noticeably softer to the touch.
  • the Insulated webs have lower pressure drop (PD) during filtration data than the uninsulated webs. This can be attributed to the added fluffiness noted above.
  • the filtration efficiency data for the aged insulated webs are, in general, higher than the data for the uninsulated webs. While the efficiencies tend to be higher for the insulated webs, the sample weights of the insulated webs are actually less than their uninsulated counterparts. Therefore, the improved efficiency appears to be related to the increase in surface potential. While the improvement in the efficiency appears to be small, it should be noted that an increase in efficiency from, for example, 97% to 98% effectively decreases the number of unfiltered particles by a factor of one-third.
  • the Invention may be used to produce electrically charged webs useful in a variety of applications.
  • the present invention may be useful for applications 1n which better flufflness and softness of the nonwoven fabric having low air pressure drop are desirable properties.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Nonwoven Fabrics (AREA)
  • Filtering Materials (AREA)

Abstract

Procédé et appareil utilisant un tambour collecteur isolé essentiellement non perméable concurremment avec un système de soufflage de matière en fusion équipé de dispositifs pour charger électriquement des fibres obtenues par soufflage de matière en fusion. La présente invention permet de produire des bandes souples, électriquement chargées.
PCT/US1991/003693 1990-05-29 1991-05-28 Collecteur isole servant a la production de bandes obtenues par soufflage de matiere en fusion et chargees electriquement WO1991019034A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US52932390A 1990-05-29 1990-05-29
US529,323 1990-05-29

Publications (1)

Publication Number Publication Date
WO1991019034A1 true WO1991019034A1 (fr) 1991-12-12

Family

ID=24109437

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/003693 WO1991019034A1 (fr) 1990-05-29 1991-05-28 Collecteur isole servant a la production de bandes obtenues par soufflage de matiere en fusion et chargees electriquement

Country Status (1)

Country Link
WO (1) WO1991019034A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994007383A1 (fr) * 1992-09-28 1994-04-14 Exxon Chemical Patents Inc. Filtre de cigarette et son procede de fabrication
WO1994009200A1 (fr) * 1992-10-14 1994-04-28 Exxon Chemical Patents Inc. Tissu souffle par fusion
US5721180A (en) * 1995-12-22 1998-02-24 Pike; Richard Daniel Laminate filter media
US6709623B2 (en) 2000-12-22 2004-03-23 Kimberly-Clark Worldwide, Inc. Process of and apparatus for making a nonwoven web
WO2007022389A1 (fr) * 2005-08-17 2007-02-22 E. I. Du Pont De Nemours And Company Dispositif ameliore permettant de charger des fibres
US7488441B2 (en) 2002-06-15 2009-02-10 Kimberly-Clark Worldwide, Inc. Use of a pulsating power supply for electrostatic charging of nonwovens
WO2015093730A1 (fr) * 2013-12-18 2015-06-25 주식회사 에이앤에프 Appareil de formation de motif de type électrofilage

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2234008A1 (de) * 1972-07-11 1974-01-24 Exxon Research Engineering Co Verfahren zur herstellung von schichtstoffen
GB1387727A (en) * 1972-07-11 1975-03-19 Exxon Research Engineering Co Non-woven polymer laminate
US3878014A (en) * 1973-04-30 1975-04-15 Beloit Corp Process for matting melt blow microfibers
US3978185A (en) * 1968-12-23 1976-08-31 Exxon Research And Engineering Company Melt blowing process
US4904174A (en) * 1988-09-15 1990-02-27 Peter Moosmayer Apparatus for electrically charging meltblown webs (B-001)

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3978185A (en) * 1968-12-23 1976-08-31 Exxon Research And Engineering Company Melt blowing process
DE2234008A1 (de) * 1972-07-11 1974-01-24 Exxon Research Engineering Co Verfahren zur herstellung von schichtstoffen
GB1387727A (en) * 1972-07-11 1975-03-19 Exxon Research Engineering Co Non-woven polymer laminate
US3878014A (en) * 1973-04-30 1975-04-15 Beloit Corp Process for matting melt blow microfibers
US4904174A (en) * 1988-09-15 1990-02-27 Peter Moosmayer Apparatus for electrically charging meltblown webs (B-001)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994007383A1 (fr) * 1992-09-28 1994-04-14 Exxon Chemical Patents Inc. Filtre de cigarette et son procede de fabrication
WO1994009200A1 (fr) * 1992-10-14 1994-04-28 Exxon Chemical Patents Inc. Tissu souffle par fusion
US5721180A (en) * 1995-12-22 1998-02-24 Pike; Richard Daniel Laminate filter media
US5873968A (en) * 1995-12-22 1999-02-23 Kimberly-Clark Worldwide, Inc. Laminate filter media
US6709623B2 (en) 2000-12-22 2004-03-23 Kimberly-Clark Worldwide, Inc. Process of and apparatus for making a nonwoven web
US7488441B2 (en) 2002-06-15 2009-02-10 Kimberly-Clark Worldwide, Inc. Use of a pulsating power supply for electrostatic charging of nonwovens
WO2007022389A1 (fr) * 2005-08-17 2007-02-22 E. I. Du Pont De Nemours And Company Dispositif ameliore permettant de charger des fibres
US7465159B2 (en) 2005-08-17 2008-12-16 E.I. Du Pont De Nemours And Company Fiber charging apparatus
EP2390388A1 (fr) * 2005-08-17 2011-11-30 E.I. Du Pont De Nemours And Company Appareil de chargement amélioré de fibres
KR101289997B1 (ko) 2005-08-17 2013-07-30 이 아이 듀폰 디 네모아 앤드 캄파니 향상된 섬유 하전 장치
WO2015093730A1 (fr) * 2013-12-18 2015-06-25 주식회사 에이앤에프 Appareil de formation de motif de type électrofilage
US10106915B2 (en) 2013-12-18 2018-10-23 Anf Inc. Electro-spinning type pattern forming apparatus

Similar Documents

Publication Publication Date Title
US5227172A (en) Charged collector apparatus for the production of meltblown electrets
US4904174A (en) Apparatus for electrically charging meltblown webs (B-001)
EP0245108B1 (fr) Procédé et appareil pour la fabrication d'une nappe fibreuse non tissée
AU689757B2 (en) Method for electrostatic charging of film
US4375718A (en) Method of making fibrous electrets
US4623438A (en) Electret making process using corona discharge
CA1122546A (fr) Electrets fibreux faconnes par soufflage
US4592815A (en) Method of manufacturing an electret filter
JP5143815B2 (ja) 空気清浄装置
JPH06501750A (ja) 溶融吹出しウェブ用帯電装置及び方法
US4944854A (en) Electret process and products
US5871836A (en) Composite pleated fibrous structures containing split film fibers
JPH0260761B2 (fr)
JP7033233B2 (ja) 電界紡糸装置及び繊維シートの製造方法
WO1991019034A1 (fr) Collecteur isole servant a la production de bandes obtenues par soufflage de matiere en fusion et chargees electriquement
JPH02104765A (ja) エレクトレット不織布の製造方法
JP2001170519A (ja) 電気集塵機用集塵シート及びこの集塵シートを用いた電気集塵機
JP2817238B2 (ja) エレクトレット化多孔質シートの製造方法
JPH03249252A (ja) メルトブロー装置と同方法
JPH06257065A (ja) 超高性能エレクトレットメルトブロー不織布
JP2001190983A (ja) 電気集塵機用集塵シート及び電気集塵機
JP3129498B2 (ja) 不織布の製造法
Tsai et al. Air Filtration Improved by Electrostatically Charging Fibrous Materials
JPH06104953B2 (ja) エレクトレット化された不織布積層体の製造方法
JPH0515717A (ja) エレクトレツト繊維フイルター

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE