Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/06—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyolefin as constituent
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/28—Formation of filaments, threads, or the like while mixing different spinning solutions or melts during the spinning operation; Spinnerette packs therefor
  • D01D5/30—Conjugate filaments; Spinnerette packs therefor
  • D01D5/34—Core-skin structure; Spinnerette packs therefor
• • 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
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/14—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic yarns or filaments produced by welding
• • 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
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/16—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• • 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]
  • Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
• • 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]
  • Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
  • Y10T442/641—Sheath-core multicomponent strand or fiber material

Definitions

• Non-woven fabrics made from polymeric materials are used to make a variety of products, which desirably have particular levels of softness, strength, uniformity, liquid handling properties such as absorbency, and other physical properties.
• Such products include towels, industrial wipes, incontinence products, infant care products such as baby diapers, absorbent feminine care products, and garments such as medical apparel. These products are often made with multiple layers of non-woven fabric to obtain the desired combination of properties.
• the nonwoven fabrics are created from spunbond filaments that are formed by melt spinning thermoplastic materials.
• Methods for making spunbond non-woven fabrics are well known and disclosed, for instance, in U. S. Patent No. 4,692,618 to Dorschner, et al., U. S. Patent No. 4,340,563 to Appel, et al., and U. S. Patent No. 5,418,045 to Pike, et al., which are all incorporated herein by reference.
• Spunbond non-woven polymeric webs are formed by extruding thermoplastic materials through a spinneret and drawing the extruded material into filaments with a stream of high velocity air to form a random web on a collecting surface.
• spunbond non-woven fabrics are formed from multi-component filaments, such as bicomponent filaments.
• Bicomponent filaments are filaments made from first and second polymeric components which remain distinct within the filament.
• the filament can be in a sheath and core arrangement in which a first polymeric component makes up the core and the second polymeric component makes up the sheath.
• very useful bicomponent spunbond filaments have been made that contained a core polymer made from polyethylene and a sheath polymer made from polypropylene. The sheath polymer generally had a lower melting temperature than the core polymer to allow the filaments to be easily thermally bonded together.
• the sheath polymer also provided softness to the resulting non- woven web.
• the core polymer on the other hand, provided strength to the web.
• the present invention is directed to spunbond multi-component filaments and to non-woven webs made from the filaments.
• the present invention is directed to a non-woven web containing continuous polymeric multi-component filaments.
• the polymeric filaments include a sheath polymer and a core polymer.
• the sheath polymer comprises a copolymer of a polypropylene polymer and a monomer.
• the core polymer comprises a polypropylene polymer.
• the core polymer has a melting temperature that is at least about 8°C (15°F) greater than the melting temperature of the sheath polymer.
• the sheath polymer can be present in the continuous filament in an amount from about 20% by weight to about 70% by weight, and particularly from about 40% by weight to about 60% by weight.
• the sheath polymer can comprise a randomized copolymer of the polypropylene and the monomer.
• the monomer can be, for instance, ethylene.
• the sheath polymer is a randomized copolymer of polypropylene and ethylene.
• the ethylene is present in the sheath polymer in an amount of less than about 2% by weight and particularly less than about 1.8% by weight. It has been discovered by the present inventors that various benefits and advantages are achieved if the amount of ethylene present in the sheath polymer is below about 2% by weight.
• the core polymer can be about 98% by weight polypropylene.
• the core polymer can be a metallocene catalyzed polypropylene.
• the melt flow rating of the sheath polymer and the core polymer can be from about 30 g/10 minutes to about 40 g/10 minutes, and particularly from about 30 g/10 minutes to about 35 g/10 minutes.
• the sheath polymer can have a melting temperature of from about 110 °C to about 150°C.
• the core polymer can have a melting temperature that is at least about 8°C greater than the melting temperature of the sheath polymer.
• Figure 1 is a cross-sectional view of one embodiment of a bi-component filament made in accordance with the present invention.
• Figure 2 is a schematic drawing of one embodiment of a process line that can be used to make filaments in accordance with the present invention.
• the present invention is directed to non-woven webs made from multi-component polymeric filaments.
• the non-woven webs are made so as to have a desired balance of physical properties.
• the multi-component polymeric filaments are continuous bicomponent filaments that contain a core polymer surrounded by a sheath polymer.
• both the core polymer and the sheath polymer contain primarily polypropylene.
• the sheath polymer can be a randomized copolymer of polypropylene
• the core polymer can be a crystaline polypropylene polymer having a relatively high melting point.
• non-woven webs when using selected polypropylene polymers to construct the bicomponent filaments, non-woven webs can be formed that have improved strength and tear properties in comparison to non-woven webs made from monocomponent filaments, while also remaining soft and absorbent.
• non-woven webs with improved properties can be formed according to the present invention using relatively inexpensive polypropylene materials, as opposed to resorting to the use of more expensive exotic polymers to enhance bonding or tenacity.
• the filament 100 is a bicomponent filament including a core polymer 200 surrounded by a sheath polymer 300.
• the core polymer 200 and the sheath polymer 300 are both made primarily from polypropylene polymers.
• the filament 100 is a spunbond filament that can be continuous.
• the copolymer 200 and the sheath polymer 300 are arranged in distinctive zones across the cross section of the filament 100. Both polymers extend the entire distance of the filament 100.
• the core polymer 200 is shown substantially concentric with the sheath polymer 300. It should be understood, however, that the core polymer and the sheath polymer can be placed in various other arrangements. For instance, the core polymer 200 and the sheath polymer 300 can be placed in an eccentric arrangement as well.
• the sheath polymer 300 has a lower melting temperature than the core polymer 200. In this manner, the sheath polymer 300 of one filament can easily melt and fuse with the sheath polymer of an adjacent filament during the formation of non-woven webs. Bonding can occur between adjacent filaments without melting the core polymer 200, which provides the filament with increased strength.
• the sheath polymer 300 used to make filaments and non-woven webs in accordance with the present invention primarily contains a polypropylene polymer, such as a crystalline polypropylene.
• the polypropylene polymer should have a relatively low melt temperature, such as a melt temperature of less than about 150°C.
• the melt temperature of the polypropylene sheath polymer can be from about 110°C to about 150°C and more particularly from about 120°C to about 135°C.
• the melt flow rating of the polymer can be from about 30 g/10 minutes to about 40 g/10 minutes, and particularly from about 30 g/10 minutes to about 35 g/10 minutes.
• the above-described melt flow ranges are particularly well-suited for the formation of spunbond filaments in melt spinning operations.
• the sheath polymer is a copolymer of a polypropylene and a monomer, particularly a randomized copolymer of a polypropylene and a monomer.
• the monomer can be, for instance, ethylene or butene.
• the amount of monomer contained within the randomized polypropylene copolymer should be relatively low in some applications. Specifically, it has been discovered by the present inventors that the monomer should be present within the randomized copolymer in an amount of less than about 2% by weight, particularly less than about 1.8% by weight.
• the monomer can be ethylene and can be contained in the randomized copolymer in an amount of less than about 1.6% by weight.
• the sheath polymer can be a randomized copolymer of polypropylene and ethylene sold by Dow Chemical under the product number 6D43.
• Dow Chemical 6D43 polymer contains ethylene in an amount of about 3.2% by weight.
• greater amounts of polypropylene or another suitable polymer can be added to the product in order to reduce the monomer levels.
• the sheath polymer should contain polypropylene in an amount of about 95% by weight.
• the sheath polymer can contain a monomer as described above and other additional additives.
• additives can include antioxidants, heat stabilizers, other stabilizers, and the like.
• the sheath polymer not only provides softness to spunbond filaments and non-woven webs made in accordance with the present invention, but also improves the toughness of the webs. For instance, due to its lower melting temperature, the sheath polymer has a softer feel. Further, also because the sheath polymer has a lower melting temperature, the sheath polymer is well adapted to melting and fusing with adjacent fibers. In fact, since the sheath polymer can easily melt with other filament fibers during bonding, non-woven webs formed in accordance with the present invention have greater integrity and toughness.
• the core polymer 200 as shown in Figure 1 also contains primarily polypropylene.
• the core polymer generally has a higher melting temperature than the sheath polymer.
• the core polymer can have a melting temperature that is at least about 8°C (15°F) higher than the melting temperature of the sheath polymer, and particularly can have a melting temperature from about 8°C higher to about 15°C higher than the sheath polymer.
• the core polymer can have a melting temperature of greater than about 150°C, and particularly greater than about 155°C.
• the core polymer generally does not significantly melt or degrade.
• the core polymer is present in the filament in order to increase the strength of the filament and to increase the strength of non-woven webs made from the filaments.
• the core polymer contains a homopolymer of polypropylene in an amount of at least about 95% by weight.
• Other polymers and additives can be combined with the core polymer in relatively small amounts.
• the core polymer can have a melt flow rating of from about 30 g/10 minutes to about 40 g/10 minutes, and particularly from about 33 g/10 minutes to about 39 g/10 minutes.
• the polypropylene contained in the core polymer can be a Ziegler-Natta catalyzed polymer or, alternatively, can be a metallocene catalyzed polymer.
• Metallocene catalyzed polymers provide various advantages including offering the possibility of providing a polymer with a relatively low molecular weight distribution.
• the core polymer is product number 3155 or 3854 marketed by the Exxon Corporation.
• the sheath polymer is present in the filament in an amount from about 20% to about 70% by weight and particularly in amount from about 40% to about 60% by weight.
• a process line generally 10 for preparing spunbond filaments in accordance with the present invention is illustrated.
• the process line 10 is arranged to produce bicomponent continuous filaments and to produce non-woven webs made from the spunbond filaments.
• the process line 10 includes a pair of extruders 12A and 12B for separately extruding a sheath polymer and a core polymer.
• the sheath polymer is fed into the extruder 12A from a first hopper 14A and the core polymer is fed into the extruder 12B from a second hopper 14B.
• the spinneret 18 includes a housing containing a spin pack which includes a plurality of plates stacked one on top of the other with a pattern of openings arranged to create flow paths for directing polymer components through the spinneret.
• the spinneret 18 has openings arranged in one or more rows. The spinneret openings form a downwardly extending curtain of filaments when the polymers are extruded through the spinneret.
• the process line 10 also includes a quench blower 20 positioned adjacent the curtain of filaments extending from the spinneret 18. Air from the quench air blower 20 quenches the filaments extending from the spinneret 18. The quencher can be directed from one side of the filament curtain as shown in Figure 2, or both sides of the filament curtain.
• the process line can further include a fiber draw unit or aspirator 22 positioned below the spinneret that receives the quenched filaments.
• Fiber draw units or aspirators for use in melt spinning polymers are well known as discussed above.
• the fiber draw unit 22 includes an elongate vertical passage through which the filaments are drawn by aspirating air entering from the sides of the passage and flowing downwardly through the passage.
• a heater 24 can supply hot aspirating air to the fiber drawn unit 22. The hot aspirating air draws the filaments and ambient air through the fiber draw unit.
• An foraminous forming surface 26 is positioned below the fiber draw unit 22 and receives the continuous filaments from the outlet opening of the fiber draw unit.
• the forming surface 26 travels around guide roll 28.
• a vacuum 30 positioned below the forming surface 26 where the filaments are deposited draws the filaments against the forming surface.
• the process line 10 further includes a compression roller 32 which, along with the forward most of the guide rollers 28, receives the web as the web is drawn off of the forming surface 26. From the compression roller 32, the web is fed to a winding roll 42 for taking up the finished fabric. Prior to winding the web onto the roll 42, the process line can further include some type of bonding apparatus such as thermal point bonding rollers and/or a through-air bonder. Thermal point bonders and through-air bonders are well known to those skilled in the art and are not disclosed here in detail.
• the hoppers 14A and 14B are filled with the respective polymer components.
• the core polymer and the sheath polymer are melted and extruded by the respective extruders 12A and 12B through polymer conduit 16A and 16B and the spinneret 18.
• the polymers are heated to temperatures sufficient for the polymers to be flowable.
• a stream of air from the quench blower 20 at least partially quenches the filaments.
• the quench air for instance, can flow in a direction substantially perpendicular to the length of the filaments.
• the temperature of the quench air can be from about 45°F to about 90°F and can be at a velocity of from about 100 to 400 feet per minute.
• the filaments are drawn into the vertical passage of the fiber draw unit 22 by a flow of hot air from the heater 24 through the fiber draw unit. It should be understood, however, that the use of a fiber draw unit is optional.
• the fiber draw unit can be used, for instance, to cause the filaments to slightly crimp.
• the filaments After exiting the fiber draw unit 22, the filaments are deposited onto the traveling forming surface 26.
• the vacuum 20 draws the filaments against the forming surface to form an unbonded, non-woven web of continuous filaments.
• the web is then lightly compressed by the compression roller 32.
• the web can be bonded together using any suitable technique, such as by using thermal point bonded rollers or by using a through-air bonder.
• a through-air bonder air having a temperature above the melting temperature of the sheath polymer and below the melting temperature of the core polymer is directed from a hood and through the web.
• the hot air melts the sheath polymer thereby forming bonds between the bicomponent filaments to integrate the web.
• the temperature of air flowing through the bonder can be from about 230°F to about 280°F and can be at a velocity of from about 100 to about 500 feet per minute.
• the finished web is wound into the winder roller 42 and is ready for further treatment or use.
• Spunbond non-woven webs constructed in accordance with the present invention have been found to offer various advantages and benefits. For instance, the non-woven webs have been found to have increased tensile strength and tear strength in relation to webs made only with a polypropylene polymer. In fact, the webs have exhibited properties favorably comparable to conventionally made bicomponent filaments. Since the filaments of the present invention, however, are made almost exclusively of polypropylene polymers, the filaments are relatively inexpensive to produce.
• Spunbond non-woven webs made in accordance with the present invention can be used in numerous applications.
• the spunbond webs can be used for making personal care articles and garment materials.
• Personal care articles include infant care products such as disposable baby diapers, child care products such as training pants, and adult care products such as incontinence products and feminine care products.
• Suitable garments include medical apparel, work ware and the like.
• spunbond non-woven webs made in accordance with the present invention can be combined with other webs for forming laminates.
• the spunbond webs can be laminated to other spunbond webs or to meltblown webs.
• a spunbond/melt blown/spunbond laminate is formed containing the non-woven webs of the present invention.
• the basis weight of the non-woven webs can be, for instance, from about 0.25 OSY to about 3 OSY, and particularly from about 0.50 OSY to about 2 OSY.
• a spunbond/melt blown/spunbond laminate can be formed in which each layer has a basis weight of about 1 OSY.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Multicomponent Fibers (AREA)
• Nonwoven Fabrics (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2002
  • 2002-08-21 US US10/225,450 patent/US20040038612A1/en not_active Abandoned
• 2003
  • 2003-06-25 BR BR0313263A patent/BR0313263A/pt not_active IP Right Cessation
  • 2003-06-25 WO PCT/US2003/020138 patent/WO2004018746A1/en active Application Filing
  • 2003-06-25 CN CNB038191148A patent/CN1311112C/zh not_active Expired - Fee Related
  • 2003-06-25 AU AU2003253716A patent/AU2003253716B2/en not_active Ceased
  • 2003-06-25 MX MXPA05001376A patent/MXPA05001376A/es unknown
  • 2003-06-25 JP JP2004530807A patent/JP2005536657A/ja active Pending
  • 2003-06-25 EP EP20030792951 patent/EP1530655A1/en not_active Withdrawn
  • 2003-06-25 KR KR1020057002018A patent/KR20050056950A/ko not_active Ceased

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