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  Nonwoven fabric having improved performanceUSPTO Application #: 20070181242Title: Nonwoven fabric having improved performance Abstract: The present invention relates generally to nonwoven materials, and specifically, to a nonwoven fabric comprised of at least three continuous filament precursor webs, each precursor web being of a thermoplastic polymer dissimilar from the other precursor webs, wherein the resulting durable nonwoven laminate fabric exhibits improved tactile and ductile qualities, as well as improved tensile strength, the nonwoven fabric being eminently suitable for application in improving the comfort and use of hygiene, medical and industrial products. (end of abstract)
Agent: Valerie Calloway Chief Intellectual Property Counsel - Charlotte, NC, US Inventors: Errette Bevins, Nick Carter, Sergio Diaz de Leon USPTO Applicaton #: 20070181242 - Class: 156167000 (USPTO) Related Patent Categories: Adhesive Bonding And Miscellaneous Chemical Manufacture, Methods, Surface Bonding And/or Assembly Therefor, Bonding Of Flexible Filamentary Material While In Indefinite Length Or Running Length, With Formation Of Filaments The Patent Description & Claims data below is from USPTO Patent Application 20070181242. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] The present invention relates generally to nonwoven materials, and specifically, to a nonwoven fabric comprised of at least three continuous filament precursor webs formed from a juxtaposition of a first outer layer comprising a thermoplastic precursor web of continuous filaments, a second outer layer thermoplastic precursor web, also of continuous filaments, and a central thermoplastic precursor web of continuous filaments positioned between the first and second outer layer, each precursor web being of a thermoplastic polymer dissimilar from at least one of the other precursor webs, wherein the resulting nonwoven laminate fabric exhibits improved tactile and ductile qualities, as well as strength, the nonwoven fabric being immanently suitable for application in improving the comfort and use of hygiene, medical and industrial products. BACKGROUND OF THE INVENTION [0002] Nonwoven fabrics are used in a wide variety of applications where the engineered qualities of the fabrics can be advantageously employed. The use of selected thermoplastic polymers in the construction of the fibrous fabric component, selected treatment of the fibrous component (either while in fibrous form or in an integrated structure), and selected use of various mechanisms by which the fibrous component is integrated into a useful fabric, are typical variables by which to adjust and alter the performance of the resultant nonwoven fabric. [0003] Disposable hygiene products and personal protective apparel readily employ nonwoven fabrics in their respective constructions. Such nonwoven fabrics come in to intimate contact with the human skin for prolonged periods of time. The comfort of the product is subsequently directly attributed to the way in which the product touches the skin, the weight of the product as it is worn, and the ability of the product to conform and adapt to changes in user position. In acknowledgment of the importance of the product/human interface, conventional nonwoven fabric manufactures have gone to great efforts to improved the tactile and ductile performance of their fabrics. [0004] Two general approaches to improving the comfort of a nonwoven fabric include chemical and mechanical alteration. Representative prior art to the use of chemical alteration of the nonwoven fabric are: U.S. Pat. No. 6,290,979, to Roe et al., teaches to the use of a first and a second skin care composition to affect the comfort of a disposable diaper; and Applicant's co-pending application, directed to the use of a two-part fatty acid amide melt additive, involves the introduction of the melt additive into the nonwoven fabric during manufacture. Mechanical alteration has been presented in the prior art in such forms as compressive technologies (MICREXING is described in U.S. Pat. No. 3,260,778, No. 3,416,192, No. 3,810,280, No. 4,090,385; and No. 4,717,329) and alternate nonwoven fabric formation technologies (as typified by U.S. Pat. No. 6,340,413 to Nilsson, et al.). [0005] U.S. Pat. No. 5,766,737, to Willey et al., directed to a multilayered barrier fabric, teaches a nonwoven fabric having differential aesthetic properties obtained by the necessary incorporation of barrier meltblown layer. Such a laminate as taught by Willey et al., includes a significant quantity of meltblown material, and overall laminate basis weight, so as to render the material suitable for independent use in medical applications. [0006] There remains an unmet need for a soft, strong, and durable nonwoven fabric, which can be used in improving the comfort of hygiene, medical and industrial products, which does not necessarily involve the use of additional additives or complex manufacturing procedures, nor adversely affects the performance of the construct or product to which it is adjoined. SUMMARY OF THE INVENTION [0007] The present invention relates generally to nonwoven materials, and specifically, to a nonwoven fabric comprised of at least three continuous filament precursor webs, each precursor web being of a thermoplastic polymer dissimilar from the other precursor webs, wherein the resulting durable nonwoven laminate fabric exhibits improved tactile and ductile qualities, as well as improved tensile strength, the nonwoven fabric being eminently suitable for application in improving the comfort and use of hygiene, medical and industrial products. The nonwoven fabric is manufactured with a minimum level of process complexity, and can be either used as an absorbent article component, such as a liner for feminine hygiene products, as well as a topsheet or backsheet, when laminated with a film. The fabric is also suitable for surgical face mask material, wherein the fabric provides durability, in addition to comfort. [0008] In a first embodiment, the nonwoven fabrics made in accordance with the present invention are formed from a juxtaposition of a first outer layer comprising a thermoplastic precursor web of continuous filaments, a second outer layer thermoplastic precursor web, also of continuous filaments, and a central thermoplastic precursor web of continuous filaments positioned between the first and second outer layers. Optionally, the continuous filament layers may be directly extruded onto one another in an in-line process. It is also within the purview of the invention to incorporate additional continuous filament layers into the nonwoven laminate. [0009] In a second embodiment, the nonwoven fabrics made in accordance with the present invention are formed from extruding more than one type of thermoplastic continuous filament from the same spinneret, so as to incorporate more than one type of thermoplastic filament within the same precursor web. The resultant continuous filament precursor web may comprise a first thermoplastic forming a first filamentary zone and a dissimilar second thermoplastic forming a second filamentary zone. Further, the entire precursor web may comprise an even distribution of more than one thermoplastic continuous filament throughout the length and width of the web. Subsequently, the precursor webs may be positioned according the process mentioned above. [0010] The thermoplastic polymers of the continuous filament precursor webs are chosen from the group consisting of polyesters, polyamides, nylons, polyolefins, such as polypropylene, polyethylene, and the derivatives and/or the combinations thereof. Further, the first and second outer layer precursor webs of the laminate are respectively comprised of dissimilar homogeneous filaments, as well as, performance and/or aesthetic modifying additive. [0011] It is within the purview of the present invention that the formed fabric includes one or more centrally located layers comprised of Ziegler-Natta or Metalocene based polymers, thermally compatible thermoplastic random copolymers, performance modifying agents, and the combinations thereof, which allows for the adjoining of the two dissimilar thermoplastic outer layer precursor webs. The resulting nonwoven laminate is one that has improved tactile and ductile qualities, as well as improved strength, so as to enhance the comfort and provide durability to suitable hygiene, medical, and industrial applications end-use articles. [0012] Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is a plan view of a diaper in an uncontracted state; and [0014] FIG. 2 is a plan view of a surgical gown. DETAILED DESCRIPTION [0015] While the present invention is susceptible of embodiment in various forms, there will hereinafter be described, presently preferred embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiments disclosed herein. [0016] The present invention is directed to a strong, but soft nonwoven laminate, which entails formation of a first outer layer of thermoplastic continuous filaments, preferably of polyethylene, a second outer layer of thermoplastic continuous filaments, preferably of polypropylene, and at least one centrally located thermoplastic polymer optionally comprised of a random copolymer, wherein the central layer is preferably polypropylene or a polypropylene blend. [0017] In general, the formation of continuous filament precursor webs involves the practice of the "spunbond" process. A spunbond process involves supplying a molten polymer, which is then extruded under pressure through a large number of orifices in a plate known as a spinneret or die. The resulting continuous filaments are quenched and drawn by any of a number of methods, such as slot draw systems, attenuator guns, or Godet rolls. The continuous filaments are collected as a loose web upon a moving foraminous surface, such as a wire mesh conveyor belt. When more than one spinneret is used in line for the purpose of forming a multi-layered fabric, the subsequent webs are collected upon the uppermost surface of the previously formed web. [0018] It is within the purview of the present invention that at least one of the continuous filament precursor webs may be formed from filaments having a nano-denier, as taught in U.S. Pat. No. 5,678,379 and No. 6,114,017, both incorporated herein by reference. Further, at least one of the continuous filament precursor webs may be formed from an intermingling of conventional and nano-denier filaments. [0019] In addition to the aforementioned conventional spunbond practice, the precursor webs of the present invention may be formed by extruding more than one thermoplastic, such as polypropylene, polyethylene, a random copolymer blend of polypropylene or polyethylene, or a combination thereof, from the same spinneret. Formation of the precursor web in this manner may provide for a web with two or more filamentary zones, wherein one half of the web may be formed of polypropylene filaments and the other half formed of polyethylene filaments. Further, the web may be comprised of alternating zones or the entire web may comprise an equal distribution of polypropylene and polyethylene filaments. Continue reading... Full patent description for Nonwoven fabric having improved performance Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Nonwoven fabric having improved performance patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Nonwoven fabric having improved performance or other areas of interest. ### Previous Patent Application: Adhesively bonded seams and methods of forming seams Next Patent Application: Method for embossing air-laid webs using laser engraved heated embossing rolls Industry Class: Adhesive bonding and miscellaneous chemical manufacture ### FreshPatents.com Support Thank you for viewing the Nonwoven fabric having improved performance patent info. 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