Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
• • 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
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31725—Of polyamide
  • Y10T428/31736—Next to polyester
• • 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
  • Y10T442/642—Strand or fiber material is a blend of 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]
  • Y10T442/681—Spun-bonded nonwoven fabric
• • 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]
  • Y10T442/69—Autogenously bonded nonwoven fabric
  • Y10T442/692—Containing at least two chemically different strand or fiber materials
• • 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]
  • Y10T442/697—Containing at least two chemically different strand or fiber materials

Definitions

• Nonwoven web materials are formed from multiconstituent filaments having the ability to self-bond without substantial polymer flow, disfiguration, or cross-sectional flattening when heat-treated, said multiconstituent filaments being spun from at least two different polymeric materials such that, in a given filament, a first fiber-forming polymeric material defines a matrix and a second polymeric material is dispersed therein in the form of discontinuous fibrils, said matrix comprising at least 50 percent by weight of the filament and having a lower melting point than said dispersed fibrils.
• the multiconstituent filaments may be combined with other fibrous or additive materials in a variety of ways depending on the use intended for the web.
• Nonwoven web materials are the basis for making a great variety of products. For example, they are used for, or converted into products useful as filters, scouring materials, abrasive carriers, etc. Many other applications in apparel and other industries are well known.
• Stein et al., U.S. Pat. No. 3,324,609 and Levy, U.S. Pat. No. 3,276,944.
• Stein a web formed from fusible synthetic fibers is layered with a woven web and needle punched; the portion of the fusible fibers penetrating through the woven web as a result are then anchored by flame-induced fusion.
• Levy discloses a nonwoven web composed of one or more fibers of the same or different chemical compositions, which are highly oriented, and adapted to self'bond upon exposure to a certain nonsolvating fluid atmosphere, particularly steam.
• Still other prior art disclosures include reference to use of low melting point and high melting polymers in the same nonwoven web, as for example, where certain bonding operations have employed cospun filaments, or composite filaments comprised of the two polymers in side-by-side relationship.
• the present invention involves the formation of novel nonwoven web materials employed as end products or as intermediates to end products, but with advantages in composition which afford several benefits over the previous known materials.
• the latter are achieved by incorporating in the novel nonwoven web materials of this invention, multiconstituent filament composed of at least two fiber-forming polymeric materials combined in accordance with the principles set out in Twilley U.S. Pat. No. 3,369,057 (which patent is hereby incorporated by reference as if fully set out herein).
• Twilley originally disclosed multiconstituent filaments comprised of nylon 6 and a polyester prepared for employment in highstrength yarns, useful in yarn or cord form as reinforcing strands in elastomeric tires, conveyor belts, seat belts, hoses, and the like, resulting in improved strength, durability and shape retention of these articles.
• This same combination of materials and others produced in a similar manner are useful in the nonwoven webs hereof.
• the webs hereof are comprised of continuous filament and/or staple fibers which may be combined with other polymeric materials in the manner ofa bicomponent wherein filaments are extruded side by side in a single yarn or in the form of a mechanically blended yarn comprised of several filaments twisted, braided, etc., together by well-known methods.
• the web materials will contain multiconstituent filamentary material, but in various ways within the scope of the invention as will be described.
• multiconstituent means filaments made by inclusion of at least one polymeric material in a matrix of another by discontinuous fibrils, the two materials having substantially different melt temperatures such that fibrous constructions composed thereof can be bonded by application of heat below the melt temperature of one and equal to or above that of the other, the entire filament composition or any component thereof optionally including any secondary material compatible with the bonding process and end utility of the web as a whole, such as antioxidants and other stabilizing agents, reinforcing particles, fillers, adhesion promoting agents, fluorescent materials, dispersing agents, and others useful in polymerization, extruding, spinning, fabric forming and shaping, heat-setting and product-finishing techniques.
• inorganic materials such as metal whiskers, fiber glass fibrils, asbestos particles and the like may be incorporated for conductive and/or reinforcement purposes.
• the preferred multiconstituents useful herein are comprised of a homogeneous mixture of two different polymeric materials, the lower melting material forming a matrix in which the higher melting material is dispersed throughout in the form of discontinuous microfibers.
• various polymeric materials together in accordance with this invention they need not be entirely intermiscible due to their physical properties and/or the mixing technique employed to disperse the higher melting component in the matrix material for forming microfibers.
• microsized globules or fibrils are usually initially produced in the matrix, which when spun or drawn, produce the desired microfibrillar dispersion in the lower melting matrix material.
• the filaments are generally of textile denier (approximately 1-17) for most applications, but higher or lower deniers of virtually any size are contemplated to be useful in the invention, for special applications.
• the fila ments may be crimped or straight and may be round, trilobal, elliptical, or any other cross-sectional shape.
• the principal advantages offered 'by employing multiconstituent filament is the resultant self-bonding web produced, and the improved strength, tear, durability and the high degree of versatility the material offers as an intermediate for a great variety of articles.
• the principal object of the invention is, therefore, to provide novel nonwoven webs produced at least in part from multiconstituent yarn or filamentary material.
• Another object is to provide nonwoven webs produced from continuous filaments in the form of sheetlike structures, and to provide novel methods for producing the same from continuous filaments distributed in a homogeneous, random or oriented manner with a low degree of aggregating fibers, and more particularly, to provide such nonwoven webs embodying the improved strength and bonding properties of multiconstituent filaments in a substantially isotropric or oriented structure.
• a more specific object of the invention is to provide such nonwoven webs containing filamentary material comprised of two or more fiber forming polymeric materials combined together in a lower melting matrix, higher melting dispersion, relationship.
• Another object is to provide novel nonwoven webs which will self-bond by exposure to appropriate physical conditions without using a solvating agent or a foreign binder, and without destroying (or reducing to a major extent) the strength as determined by tongue tear or breaking strength methods.
• the invention is applicable to any suitable web-forming procedure insofar as multiconstituent filaments comprise part of the web.
• the webs hereof may be formed by wet-laying, by carding, by depositing staple fibers from a Rando Webber machine, or by any of the numerous continuous filament web-laydown processes. illustrative of the latter are disclosed in the following U.S. Pats. No. Vosburgh 3,368,934; Medeiros et al. 3,384,944; Kinney 3,341,394 and IBundy et al. 3,296,678. Still further novel continuous processes hereof will be described below.
• the geometry of the filamentary web will vary considerably between filament compositions, method of web preparation, bonding system, if any, and the physical conditions to which the material is exposed during any of the above phases.
• the random positioning of highly oriented filaments produces the desired isotropic web which can exhibit strength advantages in any direction in the plane of a sheet of the web, the filaments being separate and independent for the most part,'except at crossover points.
• the strength in a particular direction for increased strength in the machine direction for example, randomness for more isotropic strength, bunching, bonding, loft, fluid permeability, and all the various other properties known to the art, may be critical.
• the web can be formed from multiconstituent filament handled in a manner similar to other known filament web ingredients to produce the various properties for a given end product.
• Such manipulation is within the art and extensive discussion which could be given can be found, for example, in the several patents cited herein.
• nonwoven webs hereof are most useful in the form of bonded sheets and most of the following description will be in this vein.
• an unbonded web serves as a useful intermediate product which can be selectively shaped and bonded according to the particular needs of the end product desired.
• multiconstituent filaments have the ability to bond to each other, and to other filaments, in a manner which does not cause significant flow or cross-sectional disfiguration, thereby setting up conditions for bonding systems that promote fiber orientation and strength and yet which admit controllable physical properties such as porosity, permeability, appearance, texture, etc.
• bonded webs formed be deposited by a continuous yarn spraying technique such as a traversing spinnerette type process which promotes or facilitates rapid bonding of heat-softened filaments in a one or two step process.
• binder fibers may consist of continuous filament of a similar chemical nature to the structural filament element but having a lower melting point.
• binder filaments may be filaments of the same chemical composition but spun with a lower level of orientation or with no orientation.
• cospun binder filaments may be highly oriented but may be ofa copolymeric nature or of some other modification which provides a lower melting temperature.
• any different filaments be employed since the principle of self-bonding may be used, in which the bonds are provided by localized fusion, partial or complete of individual portions of the fibers. Such fusion may be brought about by spark discharge through the web or the application of heat to highly localized, mechanically isolated portions of the web.
• the instant nonwoven structures may also be rendered more stable to delamination by needling techniques (see, for example, Lauterbach & Norton, U.S. Pat. No. 2,908,064).
• Bonding may be applied uniformly over the entire area of the fabric or in closely controlled patterned areas or in random patterned areas. Two or more difierent bonding techniques may be employed simultaneously or in sequence. In addition to bonding in itself, application of other materials to the nonwoven sheet structures of this invention may be employed for other purposes such as surfacing, modification of visual appearance or opacity or porosity or for providing other physical or chemical properties of a specific desired nature.
• nonwoven structures of the present invention it is also possible to laminate the nonwoven structures of the present invention to films or fabrics which are in themselves thermoplastic or may contain thermoplastic elements which can be bonded to the present webs by the application of continuous or localized areas of heat.
• Such materials are useful for the preparation of protective coverings, vapor seals, conductive materials, dielectrics and other articles of commerce.
• the multiconstituent filaments are prepared from a combination of polymeric materials, one of which is capable of acting as a low melting matrix in which a higher melting dispersion is created by suitable mixing.
• Polyester-polyamide combinations produce the most outstanding properties of any combination tested thus far.
• the compositions contain 50-90 parts by weight nylon 6 and 50l0 parts by weight of a polyester microfibrilar dispersion.
• Other particularly good materials in multiconstituents are polyolefins, polysulfones, polyphenyl oxides, polycarbonates, and other polyamides and polyesters.
• Examples of the most useful polyolefin materials are polyethylene, polypropylene, poly-l-butene, poly-Z-butene, polyisobutylene and polystyrene.
• nylon 6 polycaproamide
• nylon 610 hexamethylene-diamine-sebacic acid
• nylon 6--6 hexamethylene-diamine-adipic acid
• methanoland ethanolsoluble polyamide copolymers and other substituted polyamides such as the alkoxy-substituted polyamides.
• the preferred polyester is polyethylene terephthalate; others are polyesters of high T useful in the practice of the present invention, including those polymers in which one of the recurring units in the polyester chain is the diacyl aromatic radical from terephthalic acid, isophthalic acid, S-t-butylisophthalate, a naphthalene dicarboxylic acid such as naphthalene 2,6 and 2,7 acids, a diphenyldicarboxylic acid, a diphenyl either dicarboxylic acid, a diphenyl alkylene dicarboxylic acid, a diphenyl sulfone dicarboxylic acid, an azo dibenzoid acid, a pyridine dicarboxylic acid, a quinoline dicarboxylic acid, and analogous aromatic species including the sulfonic acid analogues; diacyl radicals containing cyclopentane or cyclohexane rings between the acyl groups; and such radicals substituted
• the multiconstituent filaments may be used alone or in combination in the same yarn or as separate entities in the nonwoven web, including natural or synthetic origin, as for example, binder, filler, or to impart other characteristics to the web.
• natural or synthetic origin as for example, binder, filler, or to impart other characteristics to the web.
• Illustrative are vegetable fibers, mineral fibers such as asbestos and glass fibers. Of course any such material employed must be compatible with any other material used and with the process conditions under which the web is formed, bonded or finished.
• Multiconstituent filament is produced in accordance with the formulation of example I in U.S. Pat. No 3,369,057, i .e., granular polyethylene terephthalate polymer was used, melting about 255 C. (DTA) and about 265 C. (optical), having density (when amorphous) of about L33 grams per cc. at 23 C. and about 1.38 grams per cc. in the form of drawn filament, having reduced viscosity of about 0.85 and having T about 65 C.
• the polyester in the form of drawn filament drawn to give ultimate elongation of about 20 percent will have tensile modulus (modulus of elasticity) ranging from about 70 to grams per denier, depending on spinning conditions employed.
• This polyester (30 parts) was mixed with 70 parts of granular polycaproamide having reduced viscosity about 1.04, T about 35 C. and density about 1.14 grams per cc. at 23 C. Amine groups in this polycaproamide had been blocked by reaction with sebacic acid, bringing the amine group analyses thereof to ll milliequivalents of Nl-l2 groups per kilogram of polymer.
• This polycaproamide contained as heat stabilizer, 50 p.p.mcopper as cupric acetate.
• the mixture of polyamide and polyester granules was blended in a double cone blender for 1 hour.
• the granular blend was dried to a moisture content of no more than 0.01 percent; then melted at 285 C. in a 3Vz-inch-diameter screw extruder operated at a rotational speed of about 39 r.p.m. to produce a pressure of 3,000 p.s.i.g. at the outlet.
• a dry nitrogen atmosphere was used to protect the blend against absorbing moisture. Residence time in the extruder was 8 minutes.
• the molten mixture thereby obtained had melt viscosity of about 2,000 poises at 285 C.
• the polyester was uniformly distributed throughout and had average particle diameter of EXAMPLE 7 about 2 microns, as observed by cooling and solidifying a sample of the melt, leaching out the polyamide component with formic acid, and examining the residual polyester material.
• the multiconstituent blend thus produced hereafter referred to by code designation as AC-OOOl was formed into The same as example 6 except that yarn feed speeds were varied, ACO001, 740 and polyethylene terephthalate filaments 1,020 feet per minute, and the relative material amounts in the nonwoven product were 94 and 6 percent respectively.
• nonwovens com- Break 7.0 m4 prised of a multiconstituent and other yarn materials such as S 23.3 Dacron, polypropylene, nylon 6. etc. Tongue Tear l8 l3 (lbs) 2.5 2.3
• EXAMPLE 6 45 CM Using the procedure given above for examples 1-5 in table 1, ACOOOl, denier 1125/70 having a heart-shape filament cross section and polyethylene terephthalate filaments of denier 60/34, round cross section, were fed in two passes onto a conveyor traveling at 8 feet per minute. Yarn speed was 990 yards per minute, and the relative amounts of each yarn was EXAMPLE 8 95 to 5 percent respectively.
• CM M Rum force indicates the pressure on an 8 Tongue Tear T (lbs-l 0.42 0.52 -inch square.
• EXAMPLE 9 The same as example 6 but using two ends of AC-0001, denier l 125/70 heart cross section and one end of polypropylene denier 3750/210 round cross section.
• the feed speeds onto a conveyor running at 14 f.p.m. were 1,350 and 620 f.p.m. respectively, and the resultant web contained 40 and 60 percent of the two materials respectively.
• the nonwoven web material of Example 1 can be fed through apparatus of the type described in Bundy U.S. Pat. No. 3,296,678, wherein the filamentary material is laid down in random nonparallel arrangement by means of a moving jet. Contained in the jet of Bundy is a relaxing chamber in which the filament material is heated prior to exit therefrom. This preheating is desirable up to the point of deleterious effect on the web laid down.
• the heat transfer fluid should therefore be approximately l-205 C. for best results.
• a conveyor belt passing through an open zone of radiant gas or electric heaters receives the web, the unpressurized zone temperature being approximately 240245. Residence time in the zone depends on the extent of fusion desired, 5-30 seconds being sufficient to effect fusion of available contact points from 10 percent to approximately percent.
• fusion can be effected by spraying molten filamentary material on a conveyor, which can but need not be in a heated zone, or the conveyor itself can be heated sufficiently to effect fusion, particularly where fusion on only one side of a web may be desired.
• a dimensionally stable nonwoven web of heattreated fusion bonded, nonwoven, nonparallel and random filamentary materials said filamentary materials being comprised of at least 15 percent by weight of multiconstituent filaments spun from at least two different polymeric materials such that, in a given filament, a first fiber-forming polymeric material defines a matrix and a second polymeric material is dispersed therein in the form of discontinuous fibrils, said matrix comprising at least 50 percent by weight of the filament and having a lower melting point than said dispersed fibrils; and said filamentary materials having been heat-treated at a temperature in the range above the melting point of the matrix but below the melting point of the dispersed fibrils such that the multiconstituent filaments thereof are set and fusion bonded at least at their cross points without substantial polymer flow, disfiguration, and cross-sectional flattening; whereby a nonwoven textile appearance is retained and said fused nonwoven filamentary material is characterized by enhanced strength, stiffness, tear and durability.
• a nonwoven web as defined in claim wherein said multiconstituent is comprised of a polyamide and a polyester in amounts ranging between 50-90 and 50-10 parts by weight, respectively.
• a nonwoven web as defined in claim 1 further comprised of a member selected from the group consisting of metal whiskers, fiber glass fibrils and asbestos particles.
• laying down a continuous sheet of nonwoven, nonparallel and random filamentary material comprised of at least percent by weight of multiconstituent filaments spun from at least two different polymeric materials such that, in a given filament, a first fiber-forming polymeric materia] defines a matrix and a second polymeric material is dispersed therein in the form of discontinuous fibrils, said matrix comprising at least about 50 percent by weight of the filament and having a lower melting point than said dispersed fibrils;

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

Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

Country Status (5)

Cited By (33)

Families Citing this family (2)

• 1968
  • 1968-12-20 US US3616160D patent/US3616160A/en not_active Expired - Lifetime
• 1969
  • 1969-11-11 NL NL6916985A patent/NL6916985A/xx unknown
  • 1969-11-20 BE BE741968D patent/BE741968A/xx unknown
  • 1969-12-11 DE DE19691962094 patent/DE1962094A1/de active Pending
  • 1969-12-18 FR FR6943890A patent/FR2026675A6/fr not_active Expired

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