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  Nonwoven loop materialUSPTO Application #: 20060148359Title: Nonwoven loop material Abstract: Disclosed herein are nonwoven loop materials suitable for use as the female component of hook and loop fastening systems. In embodiments, the loop materials may include a fibrous nonwoven web layer and an elastic substrate layer, or may include elastic fibers coformed with other fibers. Also disclosed herein is a process for forming the nonwoven loop materials. Such nonwoven loop materials are highly useful for hook and loop type closures or fastening systems in or on personal care products, protective wear garments, medical care products, bandages and the like. (end of abstract) Agent: Kimberly-clark Worldwide, Inc. - Neenah, WI, US Inventors: Paul Theodore Van Gompel, Yung Hsiang Huang USPTO Applicaton #: 20060148359 - Class: 442328000 (USPTO) Related Patent Categories: Fabric (woven, Knitted, Or Nonwoven Textile Or Cloth, Etc.), Nonwoven Fabric (i.e., Nonwoven Strand Or Fiber Material), Nonwoven Fabric Has An Elastic Quality The Patent Description & Claims data below is from USPTO Patent Application 20060148359. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] Many of the medical care products, protective wear garments, mortuary and veterinary products, and personal care products in use today are available as disposable products. By disposable, it is meant that the product is used only a few times, or even only once, before being discarded. Examples of such products include, but are not limited to, medical and health care products such as surgical drapes, gowns and bandages, protective workwear garments such as coveralls and lab coats, and infant, child and adult personal care absorbent products such as diapers, training pants, incontinence garments and pads, sanitary napkins, wipes and the like. These products need to be manufactured at a cost which is consistent with single- or limited-use disposability. [0002] Products such as the above mentioned medical, veterinary, protective and personal care products often utilize mechanical fastening systems such as hook-and-loop fastening systems, for purposes of closure or attachment. Fibrous nonwoven webs formed by extrusion processes such as spunbonding and meltblowing, and by mechanical dry-forming process such as air-laying and carding, are ideal candidates to be utilized in or as part of fibrous loop components of the hook and loop fastening system of disposable products, since the manufacture of nonwovens is often inexpensive relative to the cost of woven or knitted loop components. [0003] Therefore, in order to provide loop materials consistent with use in limited- or single-use disposable products, there remains a need for new nonwoven loop material and processes for producing the nonwoven loop materials. SUMMARY OF THE INVENTION [0004] The present invention provides a process for producing composite nonwoven loop materials that are highly suited for use in hook and loop fastening systems. In one aspect, the process for producing the composite loop materials produces a laminate composite loop material and includes the steps of providing a sheet-form elastic substrate layer and at least a first fibrous nonwoven web, the fibrous nonwoven web including fibers which are less elastic than the elastic substrate layer, interposing the elastic substrate layer and the fibrous nonwoven web in a face-to-face relation, bonding the elastic substrate layer and the fibrous nonwoven web together at spaced-apart locations to form a laminate composite material, and then extending the laminate composite in at least one direction, such as, for example, the machine direction or the cross machine direction, in an extension amount sufficient to permanently elongate at least a number of the less elastic fibers along at least a portion of the lengths of the fibers, and then retracting the laminate. In embodiments, the elastic substrate layer may be such as elastic meltblowns, elastic spunbonds or elastic films. A second fibrous nonwoven web may desirably be bonded to the elastic substrate layer on the side opposite the first fibrous nonwoven web. [0005] In another aspect, the process for producing the composite loop materials produces a coform composite loop material and includes the steps of providing a plurality of first, elastic fibers and a plurality of second fibers which are less elastic than the first, elastic fibers, coforming the first elastic fibers and the second fibers together to form a composite nonwoven web, bonding the composite nonwoven web at spaced-apart locations to form a bonded composite nonwoven web, and then extending the bonded composite nonwoven web in at least one direction, such as, for example, the machine direction or the cross machine direction, in an extension amount sufficient to permanently elongate at least a number of the second fibers along at least a portion of the lengths of the second fibers, and then retracting the composite. In embodiments, the first and second fibers may be coformed in spunbond processes, meltblown processes, combinations of spunbond and meltblown processes, or in meltblown-and-staple fiber coforming processes. [0006] The present invention further provides composite nonwoven loop materials such as may be made by the process embodiments described above. The composite loop material includes at least one elastic component and at least one loop-forming component. The loop-forming component includes fibers which form loops extending above the plane of the composite loop material, and the loops have loop ends secured or anchored in bond points. The loop-forming component fibers are less elastic than the elastic component, and at least a plurality of the loop-forming component fibers include first length portions along the fiber having a fiber cross sectional diameter which is at least 5 percent smaller than the cross sectional diameter along a second length portion of the same fiber. In embodiments, the diameter at the first length portions on at least some of the loop-forming fibers may be 10 percent smaller, 15 percent smaller, or even 20 percent or more smaller than the diameter at the second length portions. In embodiments, the elastic component may desirably be such as elastic meltblown, elastic spunbond and elastic films, and the loop-forming component may be spunbond fibers or staple fibers. The composite loop material may desirably be a laminate composite material or a coform composite material. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 schematically illustrates a nonwoven loop material. [0008] FIG. 2A-2C schematically illustrate close up view of a single loop-forming fiber during the process of making the nonwoven loop material. [0009] FIG. 3 schematically illustrates in top view a directional orientation path of a single loop-forming fiber. [0010] FIG. 4 schematically illustrates an enlarged view of certain portions of the loop-forming fiber shown in FIG. 3. DEFINITIONS [0011] As used herein and in the claims, the term "comprising" is inclusive or open-ended and does not exclude additional unrecited elements, compositional components, or method steps. Accordingly, the term "comprising" encompasses the more restrictive terms "consisting essentially of" and "consisting of". [0012] As used herein the term "polymer" generally includes but is not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometrical configurations of the material. These configurations include, but are not limited to isotactic, syndiotactic and random symmetries. As used herein the term "thermoplastic" or "thermoplastic polymer" refers to polymers that will soften and flow or melt when heat and/or pressure are applied, the changes being reversible. [0013] As used herein, the terms "elastic" and "elastomeric" are generally used to refer to a material that, upon application of a force, is stretchable to a stretched, biased length which is at least about 133 percent, or one and a third times, its relaxed, unstretched length, and which upon release of the stretching, biasing force will recover at least about 50 percent of its elongation. By way of example only, an elastic material having a relaxed, unstretched length of 10 centimeters may be elongated to at least about 13.3 centimeters by the application of a stretching or biasing force. Upon release of the stretching or biasing force the elastic material will recover to a length of not more than 11.65 centimeters. [0014] As used herein the term "fibers" refers to both staple length fibers and substantially continuous filaments, unless otherwise indicated. As used herein the term "substantially continuous" with respect to a filament or fiber means a filament or fiber having a length much greater than its diameter, for example having a length to diameter ratio in excess of about 15,000 to 1, and desirably in excess of 50,000 to 1. [0015] As used herein the term "monocomponent" fiber refers to a fiber formed from one or more extruders using only one polymer composition. This is not meant to exclude fibers or filaments formed from one polymeric extrudate to which small amounts of additives have been added for color, anti-static properties, lubrication, hydrophilicity, etc. [0016] As used herein the term "multicomponent fibers" refers to fibers or filaments that have been formed from at least two component polymers, or the same polymer with different properties or additives, extruded from separate extruders but spun together to form one fiber or filament. Multicomponent fibers are also sometimes referred to as conjugate fibers or bicomponent fibers, although more than two components may be used. The polymers are arranged in substantially constantly positioned distinct zones across the cross-section of the multicomponent fibers and extend continuously along the length of the multicomponent fibers. The configuration of such a multicomponent fiber may be, for example, a concentric or eccentric sheath/core arrangement wherein one polymer is surrounded by another, or may be a side by side arrangement, an "islands-in-the-sea" arrangement, or arranged as pie-wedge shapes or as stripes on a round, oval or rectangular cross-section fiber, or other configurations. Multicomponent fibers are taught in U.S. Pat. No. 5,108,820 to Kaneko et al. and U.S. Pat. No. 5,336,552 to Strack et al. Conjugate fibers are also taught in U.S. Pat. No. 5,382,400 to Pike et al. and may be used to produced crimp in the fibers by using the differential rates of expansion and contraction of the two (or more) polymers. For two component fibers, the polymers may be present in ratios of 75/25, 50/50, 25/75 or any other desired ratios. In addition, any given component of a multicomponent fiber may desirably comprise two or more polymers as a multiconstituent blend component. [0017] As used herein the terms "biconstituent fiber" or "multiconstituent fiber" refer to a fiber or filament formed from at least two polymers, or the same polymer with different properties or additives, extruded from the same extruder as a blend. Multiconstituent fibers do not have the polymer components arranged in substantially constantly positioned distinct zones across the cross-section of the multicomponent fibers; the polymer components may form fibrils or protofibrils that start and end at random. [0018] As used herein the terms "nonwoven web" or "nonwoven fabric" refer to a web having a structure of individual fibers or filaments that are interlaid, but not in an identifiable manner as in a knitted or woven fabric. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, spunbonding processes, airlaying processes, and carded web processes. The basis weight of nonwoven fabrics is usually expressed in grams per square meter (gsm) or ounces of material per square yard (osy) and the filament diameters useful are usually expressed in microns. (Note that to convert from osy to gsm, multiply osy by 33.91). [0019] The terms "spunbond" or "spunbond nonwoven web" refer to a nonwoven fiber or filament material of small diameter fibers that are formed by extruding molten thermoplastic polymer as fibers from a plurality of capillaries of a spinneret. The extruded fibers are cooled while being drawn by an eductive or other well known drawing mechanism. The drawn fibers are deposited or laid onto a forming surface in a generally random manner to form a loosely entangled fiber web, and then the laid fiber web is subjected to a bonding process to impart physical integrity and dimensional stability. The production of spunbond fabrics is disclosed, for example, in U.S. Pat. No. 4,340,563 to Appel et al., U.S. Pat. No. 3,692,618 to Dorschner et al., and U.S. Pat. No. 3,802,817 to Matsuki et al., all incorporated herein by reference in their entireties. Typically, spunbond fibers or filaments have a weight-per-unit-length in excess of about 1 denier and up to about 6 denier or higher, although both finer and heavier spunbond fibers can be produced. In terms of fiber diameter, spunbond fibers often have an average diameter of larger than 7 microns, and more particularly between about 10 and about 25 microns, and up to about 30 microns or more. [0020] As used herein the term "meltblown fibers" means fibers or microfibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments or fibers into converging high velocity gas (e.g. air) streams that attenuate the fibers of molten thermoplastic material to reduce their diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly dispersed meltblown fibers. Such a process is disclosed, for example, in U.S. Pat. No. 3,849,241 to Buntin. Meltblown fibers may be continuous or discontinuous, are often smaller than 10 microns in average diameter and are frequently smaller than 7 or even 5 microns in average diameter, and are generally tacky when deposited onto a collecting surface. Continue reading... Full patent description for Nonwoven loop material Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Nonwoven loop material 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. 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