CA2106372C - Post-treatment of non-woven webs - Google Patents

Post-treatment of non-woven webs

Info

Publication number
CA2106372C
CA2106372C CA 2106372 CA2106372A CA2106372C CA 2106372 C CA2106372 C CA 2106372C CA 2106372 CA2106372 CA 2106372 CA 2106372 A CA2106372 A CA 2106372A CA 2106372 C CA2106372 C CA 2106372C
Authority
CA
Grant status
Grant
Patent type
Prior art keywords
web
precursor
method
thermoplastic
temperature
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
CA 2106372
Other languages
French (fr)
Other versions
CA2106372A1 (en )
Inventor
Charles B. Hassenboehler, Jr.
Larry C. Wadsworth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Tennessee Research Foundation
Original Assignee
University of Tennessee Research Foundation
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
Grant date

Links

Classifications

    • DTEXTILES; PAPER
    • D06TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06CFINISHING, DRESSING, TENTERING OR STRETCHING TEXTILE FABRICS
    • D06C3/00Stretching, tentering, or spreading textile fabrics; Producing elasticity in textile fabrics
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • B01D39/163Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin sintered or bonded
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/28Plant or installations without electricity supply, e.g. using electrets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/12Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • DTEXTILES; PAPER
    • D04BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04HMAKING 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
    • D04H13/00Other non-woven fabrics
    • DTEXTILES; PAPER
    • D04BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04HMAKING 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
    • D04H3/00Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
    • D04H3/02Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of forming fleeces or layers, e.g. reorientation of yarns or filaments
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604Arrangement of the fibres in the filtering material
    • B01D2239/0622Melt-blown
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604Arrangement of the fibres in the filtering material
    • B01D2239/0627Spun-bonded
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065More than one layer present in the filtering material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065More than one layer present in the filtering material
    • B01D2239/0668The layers being joined by heat or melt-bonding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/12Special parameters characterising the filtering material
    • B01D2239/1216Pore size
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/12Special parameters characterising the filtering material
    • B01D2239/1291Other parameters

Abstract

A method for post-treating a precursor nonwoven web including consolidating the web laterally and thereby reducing the maximum pore size measure of the web. The resultant nonwoven web is also disclosed as is utilization of the product web as a filter.

Claims (15)

  1. Claim 1. A method for post treating a nonwoven web which comprises:
    (a) selecting a precursor nonwoven web made of randomly collected nonelastomeric thermoplastic fibers having a crystallinity of at least 30%, said web having a maximum processing draw ratio at break of less than 4 at a temperature at least 10°F less than the melting point of the precursor thermoplastic and at a strain rate of at least 2500 %/min, and a maximum pore size measure of from 4 to 250 microns based on ASTM F 316 - 86;
    (b) heating the precursor web at a temperature between the softening temperature and melting temperature of the thermoplastic:
    (c) drawing the heated web under tension in a substantially longitudinal direction to cause the web to consolidate laterally and thereby reduce the maximum pore size measure of the web by at least 20%, wherein the heating and drawing steps are carried out continuously by passing the precursor web into an oven at a first linear velocity and withdrawing the precursor web from the oven at a second linear velocity, the ratio of the second velocity to first velocity ranges from about 1.1:1 to 2:1: and (d) permitting the web to cool.
  2. Claim 2. The process as Claim 1 wherein the drawing step is sufficient to provide the web with a mean flow pore size measure at least 20% smaller than the mean flow pore size of the precursor web.
  3. Claim 3. The process of Claim 1 wherein the drawing step is sufficient to provide the web a packing density at least 20% greater than that of the precursor web.
  4. Claim 4. The method of Claim 1 wherein the cooling step is carried out prior to release of the drawing tension and cools the web to a temperature below the softening temperature of the thermoplastic.
  5. Claim 5. The method of Claim 1 wherein the nonwoven precursor web is a meltblown web having an average fiber diameter of 0.5 to 8 microns and having an elongation at break of less than 30% based on ASTM D 5035-90.
  6. Claim 6. The method of Claim 1 wherein the thermoplastic is a polyolefin selected from the group consisting of polypropylene, polyethylene, and copolymers thereof, and the heating step is carried out at a temperature of between 190 to 350 degrees Fahrenheit.
  7. Claim 7. The method of Claim 1 wherein the thermoplastic is selected from polyesters, polyamides, cellulose triacetate, cellulose diacetate, poly-4-methylpenetene-1, polyphenelene sulfide, liquid crystal polymers and fluropolymers.
  8. Claim 8. The method of Claim 6 wherein the meltblown precursor web has randomly distributed throughout fiber-fiber bonding.
  9. Claim 9. The method of Claim 1 wherein the precursor nonwoven web is a spun-bond web having fibers of from 7 to 50 micron average diameter and having spaced apart bonds distributed through the web.
  10. Claim 10. The method of Claim 1 and further comprising the step of passing the drawn web over a bar or roller having a surface to impart transverse compression forces inwardly of the width of the web.
  11. Claim 11. The method of Claim 5 wherein the precursor nonwoven web has a breaking elongation less than 40% based on ASTM D 5035-90.
  12. Claim 12. The method of Claim 1 wherein the first velocity is controlled by passing the precursor web through the nip of first counter rotating rollers prior to the heating step, and the second velocity is controlled by passing the consolidated web through the nip of second counter rotating rollers after the heating step, and wherein the consolidated web is permitted to cool to a temperature below the softening point of the thermoplastic prior to passing through the nip of the second counter rotating roller.
  13. Claim 13. The method of Claim 1 wherein the precursor nonwoven web is made of a laminate of at least two distinct nonwoven webs, each web made of randomly collected nonelastomeric thermoplastic fibers and each web has distributed throughout fiber-fiber bonding.
  14. Claim 14. The method of Claim 14 wherein the precursor web is a composite comprising a spunbond layer, a meltblown layer, and a spunbond layer, wherein the layers are thermally bonded together at spaced apart locations.
  15. Claim 15. The method of Claim 1 wherein the precursor web has a width of 6 to 160 inches and a thick-ness of 2 to 100 mils and wherein the drawn web has a width of less than 80% of the precursor web and a thickness of 2 to 150 mils and wherein the thickness ratio of the drawn web and precursor web ranges from 1:1 to 1.5:1.
CA 2106372 1992-03-26 1993-03-26 Post-treatment of non-woven webs Expired - Lifetime CA2106372C (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US07858182 US5244482A (en) 1992-03-26 1992-03-26 Post-treatment of nonwoven webs
PCT/US1993/003090 WO1994023109A1 (en) 1992-03-26 1993-03-26 Post-treatment of nonwoven webs
CA 2106372 CA2106372C (en) 1992-03-26 1993-03-26 Post-treatment of non-woven webs

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US07858182 US5244482A (en) 1992-03-26 1992-03-26 Post-treatment of nonwoven webs
PCT/US1993/003090 WO1994023109A1 (en) 1992-03-26 1993-03-26 Post-treatment of nonwoven webs
CA 2106372 CA2106372C (en) 1992-03-26 1993-03-26 Post-treatment of non-woven webs

Publications (2)

Publication Number Publication Date
CA2106372A1 true CA2106372A1 (en) 1994-09-27
CA2106372C true CA2106372C (en) 2004-08-24

Family

ID=25676650

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2106372 Expired - Lifetime CA2106372C (en) 1992-03-26 1993-03-26 Post-treatment of non-woven webs

Country Status (1)

Country Link
CA (1) CA2106372C (en)

Also Published As

Publication number Publication date Type
CA2106372A1 (en) 1994-09-27 application

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Legal Events

Date Code Title Description
EEER Examination request
MKEX Expiry

Effective date: 20130326