WO1999010580A1 - Meltblown nonwoven web and process for making the same - Google Patents
Meltblown nonwoven web and process for making the same Download PDFInfo
- Publication number
- WO1999010580A1 WO1999010580A1 PCT/US1998/017771 US9817771W WO9910580A1 WO 1999010580 A1 WO1999010580 A1 WO 1999010580A1 US 9817771 W US9817771 W US 9817771W WO 9910580 A1 WO9910580 A1 WO 9910580A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- metallocene catalyzed
- polymer
- web
- meltblown
- laminate
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 44
- 230000008569 process Effects 0.000 title claims abstract description 35
- 239000004750 melt-blown nonwoven Substances 0.000 title claims description 11
- 229920000642 polymer Polymers 0.000 claims abstract description 80
- -1 polypropylene Polymers 0.000 claims abstract description 28
- 239000004743 Polypropylene Substances 0.000 claims abstract description 25
- 229920001155 polypropylene Polymers 0.000 claims abstract description 25
- 238000009826 distribution Methods 0.000 claims abstract description 22
- 239000000155 melt Substances 0.000 claims abstract description 22
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 11
- 239000000835 fiber Substances 0.000 claims description 21
- 229920001577 copolymer Polymers 0.000 claims description 9
- 229920000098 polyolefin Polymers 0.000 claims description 3
- 239000004745 nonwoven fabric Substances 0.000 abstract description 5
- 238000010276 construction Methods 0.000 abstract description 4
- 239000007788 liquid Substances 0.000 abstract description 4
- 230000002745 absorbent Effects 0.000 abstract 1
- 239000002250 absorbent Substances 0.000 abstract 1
- 239000004744 fabric Substances 0.000 description 7
- 239000012530 fluid Substances 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 150000002978 peroxides Chemical class 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 230000035699 permeability Effects 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 230000004888 barrier function Effects 0.000 description 3
- 125000000058 cyclopentadienyl group Chemical group C1(=CC=CC1)* 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- ZSWFCLXCOIISFI-UHFFFAOYSA-N cyclopentadiene Chemical class C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 description 2
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 2
- 229920001519 homopolymer Polymers 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 238000010094 polymer processing Methods 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 230000001954 sterilising effect Effects 0.000 description 2
- 238000004659 sterilization and disinfection Methods 0.000 description 2
- 229920005992 thermoplastic resin Polymers 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000003490 calendering Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 239000003446 ligand Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012968 metallocene catalyst Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000002952 polymeric resin Substances 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered 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
- B32B5/22—Layered 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
- B32B5/24—Layered 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
- B32B5/26—Layered 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
-
- A—HUMAN NECESSITIES
- A41—WEARING APPAREL
- A41D—OUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES
- A41D31/00—Materials specially adapted for outerwear
- A41D31/02—Layered materials
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
- A61F13/514—Backsheet, i.e. the impermeable cover or layer furthest from the skin
- A61F13/51401—Backsheet, i.e. the impermeable cover or layer furthest from the skin characterised by the material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered 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
- B32B5/02—Layered 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
- B32B5/022—Non-woven fabric
-
- 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
- D04H1/44—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 the fleeces or layers being consolidated by mechanical means, e.g. by rolling
-
- 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
- D04H1/542—Adhesive fibres
- D04H1/544—Olefin series
-
- 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
- D04H1/559—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 the fibres being within layered webs
-
- 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
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/02—Synthetic macromolecular fibres
- B32B2262/0253—Polyolefin fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/718—Weight, e.g. weight per square meter
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
- B32B2309/02—Temperature
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2432/00—Cleaning articles, e.g. mops or wipes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2437/00—Clothing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2555/00—Personal care
- B32B2555/02—Diapers or napkins
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2314/00—Polymer mixtures characterised by way of preparation
- C08L2314/06—Metallocene or single site catalysts
Definitions
- the present invention is generally directed to meltblown nonwoven webs, laminates containing meltblown nonwoven webs, and to a process for forming the webs. More particularly, the present invention is directed to a meltblown nonwoven web made from a metallocene catalyzed polymer.
- the metallocene catalyzed polymer is polypropylene having a melt flow of less than 1000 g/10 min. and a molecular weight distribution of less than about 3.0.
- Nonwoven fabric laminates are useful for a wide variety of applications. For instance, such nonwoven fabric laminates are useful for wipers, towels, industrial garments, medical garments, medical drapes, and the like.
- the laminates are used in recreational applications such as tents and as car covers.
- Disposable fabric laminates have achieved especially widespread use in hospital operating rooms for drapes, gowns, towels, foot covers, sterilization wraps, and the like.
- Nonwoven fabric laminates have also been incorporated into other products such as diapers, feminine hygiene products, and the like.
- Such nonwoven fabric laminates are typically made by combining at least one spunbond web with a meltblown web.
- a meltblown web is positioned between two outer layers of spunbond webs.
- the spunbond webs provide durability while the internal meltblown web provides a barrier layer which is porous but which inhibits the strikethrough of fluids or the penetration of bacteria from the outside of the fabric laminate to the inside.
- meltblown nonwoven webs used in the above-described laminates are made from a polypropylene resin having an initial melt flow ranging from about 400 g/10 min. to about 800 g/10 min.
- melt flow refers to a measure of the viscosity of the polymer and is expressed as the weight of material that flows from a capillary of known dimensions under a specified load or shear rate for a measured period of time and is measured in g/10 min. according to, for example, ASTM test 1238.
- the starting polymer is synthesized according to the Ziegler-Natta method in which propylene is polymerized with a catalyst that includes a transition metal salt and a metal alkyl.
- Polymers made according to this method typically have a broad molecular weight distribution and a relatively low melt flow, which can create problems when forming the polymer into a meltblown web.
- the polypropylene is then coated with from about 500 ppm to about 750 ppm of peroxide.
- the peroxide reacts with the polymer to produce a final melt flow of between about 1200 g/10 min. to about 1800 g/10 min.
- Adding peroxide has greatly improved the process of meltblowing the polymer into a web.
- the peroxide reaction can create variability in the system based on the guality of the dispersion of the peroxide on the polymer. This variability in the resin can result in basis weight uniformity problems and fiber size differences.
- a need still remains for a process that will produce a more uniform meltblown product.
- a polymer to be used in a meltblown process that is uniform in melt flow and that has a very narrow molecular weight distribution range.
- Another object of the present invention is to provide an improved process for producing a meltblown web.
- Still another object of the present invention is to provide a process for making a meltblown web using a metallocene catalyzed polymer that has a melt flow of less than 1000 g/10 min. and that has a relatively low molecular weight distribution.
- the process includes the steps of extruding a metallocene catalyzed polymer into filaments.
- the metallocene catalyzed polymer has a melt flow of less than 1000 g/10 min. , particularly from about 650 g/10 min. to about 850 g/10 min., and in one preferred embodiment has a melt flow of about 700 g/10 min.
- the filaments are contacted with a gas stream, such as hot air at a high velocity.
- the gas stream breaks the filaments into fibers.
- the fibers are then spread onto a forming surface where they form a nonwoven web.
- the metallocene catalyzed polymer used in the process of the present invention has a molecular weight distribution of less than 3.0, particularly less than 2.5, and in one embodiment, less than 2.1.
- the molecular weight distribution of a polymer is determined by dividing the weight average molecular weight of a polymer by its number average molecular weight.
- a polymer with a low molecular weight distribution contains a narrow range of molecular weights.
- a polymer that has high fluctuations in molecular weight will have a higher molecular weight distribution number.
- Metallocene catalyzed polymers that may be used in the process of the present invention to form the nonwoven web include homopolymers and copolymers of polyolefins.
- the metallocene catalyzed polymer is polypropylene or is a copolymer of polypropylene.
- the meltblown filaments are attenuated and broken into fibers by a gas.
- the fibers that are produced typically have an average diameter of from about 0.5 microns to about 50 microns, and particularly from about 0.5 microns to about 10 microns. In one embodiment, the fibers have an average diameter of from about 1 micron to about 3 microns.
- the basis weight of nonwoven webs made according to the present invention can vary and will generally depend upon the particular application for which the webs are used. For most applications, the web will have a basis weight of from about 0.35 oz/yd 2 to about 0.6 oz/yd 2 .
- meltblown nonwoven webs made according to the above described process have many uses and applications.
- the meltblown web can be incorporated into a laminate.
- the laminate can include the meltblown web adhered to at least one spunbond web.
- the meltblown web of the present invention can be positioned between a first outer spunbond web and a second outer spunbond web.
- Laminates made according to the present invention can be incorporated into various products including wipers, towels, industrial garments, medical garments, medical drapes, diapers, feminine hygiene products, tents, car covers, as well as many other various products.
- the present invention is directed to an improved nonwoven meltblown web and to a process for making the web.
- the meltblown webs are particularly well suited for use in laminates that are used to make such products as garments, wipers, diapers, feminine hygiene products, and the like.
- the meltblown webs of the present invention have improved barrier properties at equivalent basis weights.
- the nonwoven webs of the present invention are more liquid impermeable than prior art constructions.
- the nonwoven meltblown webs of the present invention also have greater fiber size uniformity and better basis weight uniformity. Further, the webs have reduced shot levels and contain less defects.
- meltblown nonwoven webs are formed from a metallocene catalyzed thermoplastic resin, such as a metallocene catalyzed polypropylene.
- the metallocene catalyzed polymer is fed to a meltblow process.
- the process of forming a nonwoven web through meltblowing involves extruding a molten polymeric material, such as a thermoplastic resin, through a die which forms filaments. As the filaments exit the die, high pressure fluid, such as heated air or steam, attenuates and breaks the filaments into discontinuous fibers of small diameter.
- the fibers are randomly deposited on a foraminous screen, drum or on a layer of material to form a web.
- the web possesses integrity due to entanglement of the individual fibers in the web as well as some degree of thermal or self-bonding between the fibers, particularly when collection is effected only a short distance after extrusion.
- the fibers that are produced during the melt blowing process and that are used to form the nonwoven web have an average diameter of from about 0.5 microns to about 50 microns. More particularly, for most applications, the fibers have an average diameter of from about 0.5 microns to about 10 microns. For instance, in one preferred embodiment, the fibers have an average diameter of from about 1 micron to about 3 microns.
- the basis weight of nonwoven webs made according to the process of the present invention will vary depending upon the particular application. When incorporated into a fabric laminate, the meltblown web can have a basis weight of from about 0.35 oz/yd 2 to about 0.60 oz/yd 2 .
- the basis weight of the web will be about 0.50 oz/yd 2 . It should be appreciated, however, that for other applications, the basis weight of the web can be much greater. For instance, in other embodiments, the basis weight can be as high as 10 oz/yd 2 and even higher.
- a metallocene catalysis refers to a metal derivative of cyclopentadiene and can be described as a homogeneous single site or constrained geometry catalysis.
- a metallocene is a neutral, ancillary ligand stabilized transition metal complex and can have the following general formula:
- Li is a cyclopentadienyl or substituted cyclopentadienyl moiety bonded to the metal through ⁇ -5 bonding
- L 2 is an organic moiety, which may or may not be a cyclopentadienyl moiety, strongly bonded to the metal which remains bonded to the metal during polymerization
- B is an optional bridging group that restricts the movement of _ ⁇ and L 2 and that modifies the angle between _ ⁇ and L 2 - M is a metal such as, for instance, titanium or zirconium X and Y are halides or other organic moieties, such as methyl groups
- metallocene can be as follows:
- Metallocene is a catalyst that initiates polymerization of a monomer to form a polymer. For instance, in order to form a metallocene catalyzed polymer, a liquid monomer, such as propylene, is combined with metallocene under constant agitation and heat. Controlled amounts of hydrogen gas are then fed to the mixture causing the polymer to form. In general, the amount of hydrogen gas fed to the reactor determines the melt flow of the resulting polymer.
- the metallocene catalyzed polymer used to form the meltblown web should have a melt flow of from about ' 500 g/10 min. to about 1,000 g/10 min., and particularly from about 650 g/10 min. to about 850 g/10 min.
- a polypropylene metallocene catalyzed polymer is used that has a melt flow of about 700 g/10 min.
- melt flow is a measure of the viscosity of the polymer and relates to the molecular weight of the polymer. It was discovered that metallocene catalyzed polymers having a high melt flow (which have a low molecular weight) have poor melt elasticity characteristics for use in a meltblown process. In particular, filaments produced from these polymers tended to break and form shot, which are imperfections contained within the web. Unexpectedly and against conventional teachings, it was then discovered that lower melt flow metallocene catalyzed polymers actually produce more uniform nonwoven webs with less defects.
- metallocene catalyzed polymers used in the present invention should have a molecular weight distribution of less than 3.0, and particularly less than 2.5.
- the polymer has a molecular weight distribution of from about 1.9 to about 2.1.
- the thermoplastic polymer that is synthesized using the metallocene catalyst for use in the present invention is preferably a homopolymer or a copolymer of a polyolefin.
- the polymer is polypropylene or a copolymer of polypropylene.
- An example of a copolymer, for instance, is a polypropylene- polyethylene random copolymer.
- thermoplastic polymer when being meltblown, is heated to a temperature of less than about 450°F, and particularly from about 350°F to about 425°F. More uniform webs are produced when the processing temperature of the polymer is less than 450°F. At higher temperatures, fluid permeability levels of the formed web may begin to decrease.
- One commercially available polymer that has been found particularly well suited for use in the present invention is a metallocene catalyzed polypropylene marketed by the Exxon Corporation.
- This polymer resin has a melt flow of about 700 g/10 min. and a molecular weight distribution of from about 1.9 to about 2.1.
- meltblown webs made according to the present invention can be used in a wide variety of applications.
- the meltblown webs can be combined with other webs of material to form a laminate.
- the meltblown web of the present invention can be combined with one or more spunbond webs to form a laminate having many commercial applications.
- laminate 10 includes a nonwoven meltblown web 12 made in accordance with the present invention spaced between a first outer spunbond web 14 and a second outer spunbond web 16.
- meltblown web 12 acts as a barrier layer between spunbond layers 14 and 16.
- a spunbond web refers to a web made from continuous filaments.
- the process for producing spunbond webs includes continuously extruding a polymer through a spinnerette to form discrete filaments. Thereafter, the filaments are drawn either mechanically or pneumatically without breaking in order to molecularly orient the polymer filaments and achieve tenacity.
- the continuous filaments are then deposited in a substantially random manner onto a carrier belt or forming surface to form a web.
- a multi-layer laminate as illustrate in the Figure may be formed by a number of different techniques including but not limited to using adhesives, needle punching, ultrasonic bonding, thermal calendering and any other method known in the art.
- such a laminate may be made by sequentially depositing onto a moving conveyor belt or forming wire first a spunbond fabric layer, then a meltblown fabric layer, and, if applicable, another spunbond layer. Once the different layers have been assembled, the layers can be bonded together as described above. Alternatively, the fabric layers may be made individually, collected in rolls, and combined in a separate bonding step.
- Laminates as illustrated in the Figure are useful for a wide variety of applications.
- such laminates can be incorporated into wipers, towels, industrial garments, medical garments, medical drapes, medical gowns, foot covers, sterilization wraps, diapers, feminine hygiene products, besides various other products.
- EXAMPLE The following example was conducted in order to demonstrate that meltblown webs made according to the process of the present invention have better uniformity and are more impermeable to fluids than webs made according to prior art methods. The following test was also performed in order to determine the effects of varying the polymer processing temperature when forming webs of the present invention.
- Polypropylene resins synthesized according to the Ziegler-Natta method and reacted with peroxide as described above were meltblown into nonwoven webs and compared with webs formed according to the present invention using a metallocene catalyzed polypropylene having a melt flow of 700 g/10 min.
- the polypropylene resins made according to the Ziegler-Natta method had varying melt flows.
- Ziegler-Natta catalyzed polymers were all meltblown into filaments at a temperature of 470°F.
- the polymer processing temperature of the metallocene catalyzed polymers was varied.
- Three different meltblown webs were constructed from polymers made according to the Ziegler-Natta method, while four different webs were constructed from the metallocene catalyzed polymer. All of the webs had a basis weight of from about 0.42 oz/yd 2 to about 0.49 oz/yd 2 .
- each of the webs was then subjected to a hydrostatic test in order to determine the permeability of the webs to liquids.
- a sample of each of the webs was placed in contact with a stream of water. The pressure of the water against the web was then increased until the water penetrated and flowed through the web. The pressure of the water was recorded once three droplets of water were observed on the side of the web opposite the fluid stream. The following results were obtained:
- the webs made from the metallocene catalyzed polypropylene were more impermeable to the fluid than the webs made from the Ziegler-Natta catalyzed polymers at approximately the same basis weights.
- metallocene catalyzed polymers are preferably processed at temperatures lower than polymers used in the past, which provides an additional advantage when using the polymers of the present invention.
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- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Health & Medical Sciences (AREA)
- Vascular Medicine (AREA)
- Dermatology (AREA)
- Epidemiology (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Nonwoven Fabrics (AREA)
- Absorbent Articles And Supports Therefor (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002299274A CA2299274A1 (en) | 1997-08-29 | 1998-08-27 | Meltblown nonwoven web and process for making the same |
AU92069/98A AU9206998A (en) | 1997-08-29 | 1998-08-27 | Meltblown nonwoven web and process for making the same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US92142797A | 1997-08-29 | 1997-08-29 | |
US08/921,427 | 1997-08-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999010580A1 true WO1999010580A1 (en) | 1999-03-04 |
Family
ID=25445410
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/017771 WO1999010580A1 (en) | 1997-08-29 | 1998-08-27 | Meltblown nonwoven web and process for making the same |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU9206998A (en) |
CA (1) | CA2299274A1 (en) |
WO (1) | WO1999010580A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7101623B2 (en) | 2004-03-19 | 2006-09-05 | Dow Global Technologies Inc. | Extensible and elastic conjugate fibers and webs having a nontacky feel |
US7101622B2 (en) | 2004-03-19 | 2006-09-05 | Dow Global Technologies Inc. | Propylene-based copolymers, a method of making the fibers and articles made from the fibers |
WO2007024447A1 (en) * | 2005-08-19 | 2007-03-01 | Dow Global Technologies, Inc. | Propylene based meltblown nonwoven layers and composite structures |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021110815A1 (en) * | 2019-12-04 | 2021-06-10 | Borealis Ag | Light weight melt blown webs with improved barrier properties |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5464688A (en) * | 1990-06-18 | 1995-11-07 | Kimberly-Clark Corporation | Nonwoven web laminates with improved barrier properties |
WO1995032091A1 (en) * | 1994-05-24 | 1995-11-30 | Exxon Chemical Patents Inc. | Fibers and fabrics incorporating lower melting propylene polymers |
JPH0941252A (en) * | 1995-07-26 | 1997-02-10 | Mitsui Petrochem Ind Ltd | Nonwoven fabric made of polypropylene |
WO1997031035A1 (en) * | 1996-02-23 | 1997-08-28 | Exxon Chemical Patents Inc. | Supported catalyst system |
US5695849A (en) * | 1996-02-20 | 1997-12-09 | Kimberly-Clark Worldwide Inc. | Elastic, breathable, barrier fabric |
US5709921A (en) * | 1995-11-13 | 1998-01-20 | Kimberly-Clark Worldwide, Inc. | Controlled hysteresis nonwoven laminates |
-
1998
- 1998-08-27 AU AU92069/98A patent/AU9206998A/en not_active Abandoned
- 1998-08-27 WO PCT/US1998/017771 patent/WO1999010580A1/en active Application Filing
- 1998-08-27 CA CA002299274A patent/CA2299274A1/en not_active Abandoned
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5464688A (en) * | 1990-06-18 | 1995-11-07 | Kimberly-Clark Corporation | Nonwoven web laminates with improved barrier properties |
WO1995032091A1 (en) * | 1994-05-24 | 1995-11-30 | Exxon Chemical Patents Inc. | Fibers and fabrics incorporating lower melting propylene polymers |
US5726103A (en) * | 1994-05-24 | 1998-03-10 | Exxon Chemical Co. | Fibers and fabrics incorporating lower melting propylene polymers |
JPH0941252A (en) * | 1995-07-26 | 1997-02-10 | Mitsui Petrochem Ind Ltd | Nonwoven fabric made of polypropylene |
US5709921A (en) * | 1995-11-13 | 1998-01-20 | Kimberly-Clark Worldwide, Inc. | Controlled hysteresis nonwoven laminates |
US5695849A (en) * | 1996-02-20 | 1997-12-09 | Kimberly-Clark Worldwide Inc. | Elastic, breathable, barrier fabric |
WO1997031035A1 (en) * | 1996-02-23 | 1997-08-28 | Exxon Chemical Patents Inc. | Supported catalyst system |
Non-Patent Citations (1)
Title |
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PATENT ABSTRACTS OF JAPAN vol. 097, no. 006 30 June 1997 (1997-06-30) * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7101623B2 (en) | 2004-03-19 | 2006-09-05 | Dow Global Technologies Inc. | Extensible and elastic conjugate fibers and webs having a nontacky feel |
US7101622B2 (en) | 2004-03-19 | 2006-09-05 | Dow Global Technologies Inc. | Propylene-based copolymers, a method of making the fibers and articles made from the fibers |
US7413803B2 (en) | 2004-03-19 | 2008-08-19 | Dow Global Technologies Inc. | Extensible and elastic conjugate fibers and webs having a nontacky feel |
WO2007024447A1 (en) * | 2005-08-19 | 2007-03-01 | Dow Global Technologies, Inc. | Propylene based meltblown nonwoven layers and composite structures |
Also Published As
Publication number | Publication date |
---|---|
CA2299274A1 (en) | 1999-03-04 |
AU9206998A (en) | 1999-03-16 |
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