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
  • D04H5/00—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length
  • D04H5/02—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length strengthened or consolidated by mechanical methods, e.g. needling
  • D04H5/03—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length strengthened or consolidated by mechanical methods, e.g. needling by fluid jet
• • 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
  • D04H1/42—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 characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/425—Cellulose 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
  • D04H1/44—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
  • D04H1/46—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 by needling or like operations to cause entanglement of fibres
  • D04H1/492—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 by needling or like operations to cause entanglement of fibres by fluid jet
• • 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
  • D04H1/46—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 by needling or like operations to cause entanglement of fibres
  • D04H1/498—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 by needling or like operations to cause entanglement of fibres entanglement of 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
  • 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

Definitions

• This present invention relates generally to composite fabrics and to a process for the manufacture thereof.
• the invention relates especially but not exclusively to composite fabrics in which a fibrous web that comprises wood-pulp fibers is joined to a spunlaid web, and to processes wherein the joining of the webs is effected by hydroentanglement.
• the present invention in one of its aspects provides a composite nonwoven fabric that comprises a first web, said first web being a nonwoven web that comprises filaments and/or fibers of man-made polymer, to which first web there is joined a second web by fiber entanglement, the second web being a fibrous web that comprises cellulose pulp fibers, characterized in that the said first web is a bonded nonwoven web that is less than fully bonded.
• the present invention in another of its aspects provides a composite nonwoven fabric that comprises a first web, said first web being a nonwoven web that comprises filaments and/or fibers of man-made polymer, to which first web there is joined a second web by fiber entanglement, the second web being a fibrous web that comprises cellulose pulp fibers, characterized in that the strength of the said first web is not more than about 45% of the strength of the said composite nonwoven fabric.
• the present invention is yet another of its aspects also provides a process for the manufacture of a composite nonwoven fabric in which a first web, being a nonwoven web that comprises filaments and/or fibers of man-made polymer, is joined to a second web by hydroentanglement, the second web being a fibrous web that comprises cellulose pulp fibers, characterized in that the said first web is a nonwoven web that is less than fully bonded.
• the present invention in a further aspect thereof provides a process for the manufacture of a composite nonwoven fabric in which a first web, being a nonwoven web that comprises filaments and/or fibers of man-made polymer, is joined to a second web by hydroentanglement, the second web being a fibrous web that comprises cellulose pulp fibers, characterized in that the strength of the said first web is not more than about 45% of the strength of the said composite nonwoven fabric.
• fiber entanglement and the like herein include fiber-filament entanglement as well as fiber-fiber entanglement.
• Figure 1 is a graph illustrating addition of varying amounts of pulp to a minimally bonded base web and the total tensile strength of the resulting composite nonwoven fabric.
• the said first web may be regarded as a base web.
• the base web material preferably comprises synthetic or other man-made filaments or fibers, in particular substantially continuous filaments.
• the base web material will generally comprise filaments or fibers made of a thermoplastic material, for example filaments or fibers of a polyamide, polyurethane, polyester or polyolefin, or a copolymer, e.g. block copolymer, containing olefin monomer units.
• the base web may also comprise, or consist of, bi- component or bi-constituent or mixed filaments or fibers. Suitable thermoplastic filamentary materials are disclosed in US-A-5 1 51 320 and
• the base web comprises polyester filaments, especially polyethylene terephthalate (PET) filaments, or polyolefin filaments, for example polyethylene or polypropylene filaments.
• PET polyethylene terephthalate
• polyolefin filaments for example polyethylene or polypropylene filaments.
• Man-made cellulosic fibers such as viscose rayon or lyocell fibers, may also come into consideration.
• the base web material may comprise a mixture of filaments or fibers of different materials, e.g., different thermoplastic materials.
• the base web material will consist of, or consist essentially of, man-made, especially synthetic, and more especially thermoplastic, filaments and/or fibers, the presence of other, non-interfering components is not precluded.
• the filaments or fibers will usually have a linear density of from 0.1 to 6 denier (0.01 1 1 to 0.667 tex), e.g., from 0.3 to 4.5 denier (0.033 to 0.5 tex) and typically from 0.5 to 3.5 denier (0.056 to 0.389 tex).
• the web should be minimally bonded sufficient for it to maintain its integrity during handling in the hydroentanglement process.
• the bonding is effected by thermal bonding, although other bonding methods, such as hydroentanglement, needle bonding, chemical bonding or adhesive bonding, may come into consideration, instead of or in addition to the thermal bonding.
• the base web is a spun-laid web.
• the base material in any embodiment should be minimally bonded and should not be fully bonded.
• Such base materials include those, which are unbonded, lightly bonded, incompletely bonded or less than fully bonded.
• such a material may be obtained by the normal methods for the production of bonded nonwoven materials with the modification that at least one of the usual bonding steps, e.g., the final bonding step, is omitted or carried out in a manner that is less intensive than normal, for example by using lower bonding temperatures, shorter bonding times, lower bonding pressures, lower entanglement energy inputs, lower needle density, lesser amounts of adhesive or other chemicals, or the like, as appropriate to the particular bonding method.
• spunlaid nonwovens or "spunbonded” materials are produced by bonding a spunlaid web by one or more techniques to provide fabric integrity.
• the spin laying of webs is disclosed, for example, in US-A-4 340 563 and US-A-3 692 61 8, the teaching is both of which is incorporated herein by reference.
• the bonding or consolidation operation is normally carried out by means of a thermal calendering process involving the application of heat and pressure to the unbonded web. Full or complete bonding of the web material is indicated by the characteristic that thermal calendering of the unbonded web material at increased temperatures and/or pressures does not improve the strength properties of the resulting web material.
• a spunlaid web comprising polyethylene terephthalate filaments may be thermally calendered at a temperature below the melting point of the polymer (about 265°C) and at a "normal" pressure to produce a fully bonded nonwoven web.
• a temperature below the melting point of the polymer about 265°C
• a "normal" pressure to produce a fully bonded nonwoven web.
• a less than-fully bonded spunlaid nonwoven material may be obtained by carrying out the thermal calendering process at a temperature that is lower than the melting point of the material from which the nonwoven has been made, for example lower than the softening point of that material and/or at a pressure below that normally used for that material.
• the above spunlaid web comprising polyethylene terephthalate filaments may be thermally calendered at a temperature of from about 80°C to 1 80°C, or more typically from about 140° C to 1 60° C and at a pressure equal to, or more preferably less than, the above normal pressure to provide a minimally bonded nonwoven web material. It is believed that the thermal calendering temperature should exceed the glass transition temperature of the polymer used, for example 80°C in the case of polyethylene terephthalate. As would be expected the selection of a particular combination of material and thermal calendering temperature and pressure will result in a nonwoven web ranging from unbonded to fully bonded. The invention is most advantageous with base web materials that have been minimally bonded to a point sufficient only to provide for base web integrity until subsequent entanglement with the below- described second web.
• the base web material prior to the entanglement process, may optionally be subjected to cross-stretching by at least 5 percent of its original extent, as described in US-A-5 1 51 320.
• the said second web Prior to the entanglement process, the said second web, being a web comprising cellulose pulp fibers, is applied to the base web material.
• the web containing cellulose pulp fibers may be applied as a pre-formed web or tissue or may be formed on the base web material, for example by means of a wet-laying or air-laying process.
• the use of a pre-formed web (e.g. one formed by a wet-laying process) containing cellulose pulp fibers is currently preferred for manufacturing reasons. Ways in which a web comprising cellulose pulp fibers may be applied to a base web material are disclosed in the above-mentioned US-A-5 1 51 320 and US-A-5 573 841 .
• the cellulose pulp fibers may be derived from a wide range of naturally occurring sources of cellulose fibers, and are preferably wood pulp fibers (including hardwood pulp, soft wood pulp and mixtures thereof), although non-wood vegetable pulp fibers such as those derived from cotton, flax sisal, hemp, jute, esparto grass, bagasse, straw and abaca fibers may also come into consideration. Mixtures of various cellulose pulp fibers may also be used.
• the cellulose pulp fibers which may be used, include conventional short papermaking fibers, particularly having a fiber length of 25mm or less.
• the average fiber length is typically greater than 0.7mm and is most preferably from about 1 .5 to 5mm.
• Conventional papermaking fibers include the conventional papermaking wood pulp fibers produced by the well-known Kraft process.
• said second web is formed entirely, or substantially entirely, of cellulose pulp fibers, and more preferably wood pulp.
• the second web may also comprise synthetic or other man-made fibers, for example in an amount of up to 50 percent by weight of the total fiber content of the cellulose fiber-containing web based on economic considerations. Synthetic or man-made fibers can be added in greater amounts to achieve other desired properties.
• man-made fibers include, for example, fibers made of rayon, polyester, polyolefin (e.g., polyethylene or polypropylene), polyamide (e.g., a nylon) or the like.
• Suitable man-made fibers include those having a fiber length of from about 3 to 25 mm and a denier per filament of 1 .0 to 3.0 (0.1 1 1 to 0.333 tex).
• the basis weights (grammages) of the first and second webs may be selected according to the fiber and/or filament constitution and the intended end use.
• the first web e.g., a spunlaid nonwoven web, will have a basis weight of, in general, from 5 to 100, preferably from 1 5 to 90 and typically from 20 to 70, grams per square meter (gsm).
• the second web for example, a web formed of wood pulp fibers, will have a basis weight of, in general, from 5 to 1 00, preferably from 1 0 to 80 and typically from 20 to 60, gsm 1
• the structure After assembly of the multi-layer structure comprising the base web material and the cellulose-fiber-containing web, the structure is subjected to a hydroentanglement operation, preferably a low to medium pressure hydroentanglement operation.
• Hydroentanglement operations are described in US-A-4 883 709 (Nozaki) and in US-A-5 009 747 (Viazmensky et al.), the disclosures of both of which are incorporated herein by reference.
• the hydroentanglement operation is preferably carried out by passing the multilayer structure under a series of fluid streams or jets that directly impinge upon the top surface of the cellulose-fiber-containing layer with sufficient force to cause a proportion of the fibers therein, especially the short papermaking fibers, to be propelled into and entangled with the base web material.
• a series or bank of jets is employed with the orifices and spacing between the orifices being substantially as disclosed in the aforesaid Nozaki patent or the Viazmensky et al. patent.
• the said fluid streams or jets are preferably streams or jets of an aqueous liquid.
• the total energy input provided by the fluid jets or streams may be calculated by the formula.
• E 0.1 25 YPG/bS
• Y the number of orifices per linear inch of manifold width
• P the pressure in psig (pounds per square inch gauge) of liquid in the manifold
• G the volumetric flow in cubic feet per minute per orifice
• S the speed of the web material under the fluid jets or streams in feet per minute
• b the basis weight of the fabric produced in ounces per square yard.
• the total amount of energy, E, expended in treating the web is the sum of the individual energy values for each pass under each manifold, if there is more than one manifold and/or if there is more than one pass.
• the total energy input is from 0.07 to 0.4 horsepower- hours per pound (HPhr/lb) (0.41 to 2.37 MJ/kg).
• the total energy input is from 0.1 to 0.3 HPhr/lb (0.59 to 1 .78 MJ/kg), more preferably from 0.1 2 to 0.28 HPhr/lb (0.71 to 1 .66 MJ/kg).
• the minimally bonded nonwoven base web material having a low bond intensity that is employed in accordance with the present invention would have been expected to provide a comparatively low-strength base for combining with the fibrous sheet or web that contains cellulose fibers.
• the strength of the composite is significantly greater than that of the starting nonwoven base web material. Moreover, it has been found that the strength of the composite increases with higher pressures and/or higher energies used in the hydroentanglement process. Thus, if a less-than-fully bonded spun-laid nonwoven material without the application of wood pulp and a comparable, less-than-fully bonded spun-laid nonwoven material to which wood pulp has been applied are subjected to the same entanglement operation profile, the final strength of the nonwoven without the wood pulp is much lower than that of the nonwoven/wood pulp composite.
• the beneficial effects of the wood pulp on the strength of the composite is unexpected because, first, there is no obvious mechanism whereby the cellulose may bond with the polymers used in the base web material (in particular PET or polypropylene) and, second, it is conceivable that the wood pulp would have acted to absorb energy from the entanglement jets and hence reduce their effect on strength generation.
• the base web material in particular PET or polypropylene
• our studies have shown that, although the starting strength of the spunbonded material may be higher, it changes much less during the entanglement process.
• the strength of the untreated base web should contribute no more than approximately 45%, preferably no more than about 40%, and more preferably no more than about 35%, of the final composite strength, in particular of the total tensile strength of the final composite.
• the strength may be measured, for example, as the tensile strength in the machine direction (MD) or cross direction (CD) or as the total tensile strength (sum of the MD + CD tensile strengths).
• the composite nonwoven fabrics manufactured according to the present invention may find use in a variety of applications, for example, as molding substrates (e.g., in the automotive industry), as geotextiles, as wiping materials, both wet and dry, and in the medical field as disposable garments such as surgical gowns and drapes.
• the composite fabrics of the present invention may include, in addition to the above-discussed fibrous components, various other additives such as surfactants, fire retardants, pigments, liquid- repellants, super-absorbents, molecular sieves, and various other particulates such as starches, activated charcoal or clay.
• the use of the present invention can give rise to products having excellent aesthetic qualities. Entanglement of pulp fibers and the like into conventional fully thermally bonded spunlaid nonwovens normally results in a non-uniform appearance. For example, the thermal bondpoints become exposed and give the impression of defects or pinholes or lack of integrity.
• a spunlaid base web having a nominal base weight of 30 gsm and comprising 100% PET 1 -denier (0.1 1 1 tex) fibers was overlaid with a tissue in the form of a web comprising wood pulp fibers (Crofton
• ECH/Harmac K1 0S ECH/Harmac K1 0S containing approximately 38 gsm bone-dry fiber.
• the resultant multi-layer composite was then passed through a production-size hydroentanglement machine in which jets of water were directed at the tissue side of the said composite. Suction was applied from beneath the composite by means of vacuum boxes, in order to remove excess water.
• Dia rows are the nozzle diameters expressed in ⁇ m.
• the density of the 90 ⁇ m holes in the injectors was 2000 per meter (51 per inch) and the density of the 1 20 ⁇ m holes was 1 666 per meter (45.2 per inch).
• the speed of the composite through the hydroentanglement machine was 46 meters per minute.
• the base webs are identified as follows:
• Web 1 Base web was bonded at 1 20°C.
• Web 2 Base web was bonded at 1 60°C.
• Web 3 Base web was bonded at 21 0°C and represents a reference, normally bonded material.
• the composite nonwoven fabrics obtained by hydroentanglement were tested for various physical properties and the results obtained are shown hereinafter.
• the test methods were: Basis Weight TAPPI T410
• Table 2 shows the results for the said composite nonwoven fabrics under the heading "Base web + tissue", the particular web being identified at the top of each column of results.
• the entanglement profile used is shown below. Tests were also carried out on samples of the starting spunbonded base webs without the addition of the tissue, and the results obtained are also shown in Table 2, under the heading "Base web”.
• Web 6 represents a reference, normally bonded material.
• Web 9 represents a reference, normally bonded material.
• Web 3 represents a reference, normally bonded material.
• the strength of the baseweb is increased by a surprisingly large amount, i.e., the total tensile strength increases from 659 N/m in the baseweb alone to 1461 N/m after entanglement with 5 gsm of woodpulp

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Nonwoven Fabrics (AREA)
• Laminated Bodies (AREA)

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• 2001
  • 2001-01-05 ES ES01900895T patent/ES2374714T3/es not_active Expired - Lifetime
  • 2001-01-05 AT AT01900895T patent/ATE526443T1/de not_active IP Right Cessation
  • 2001-01-05 WO PCT/US2001/000320 patent/WO2001049914A1/en active Application Filing
  • 2001-01-05 JP JP2001550436A patent/JP2003519298A/ja active Pending
  • 2001-01-05 EP EP01900895A patent/EP1261767B1/de not_active Revoked

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