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  Non-woven fabrics and method for producing themUSPTO Application #: 20070184741Title: Non-woven fabrics and method for producing them Abstract: The invention relates to non-woven fabrics comprising threads not produced with the spun-bonding method, for example made of non-melt spinnable thread-forming materials. The use of these fibers, optionally in combination with filaments produced using the spun-bonding method, allows the production of novel non-woven fabrics with novel property combinations. The production can be carried on conventional spun-bonding equipment, wherein part of the extruding devices are used as conveyors for the threads not produced with the spun-bonding method. (end of abstract) Agent: Grossman, Tucker, Perreault & Pfleger, PLLC - Manchester, NH, US Inventors: Robert Groten, Christoph Josefiak, Georges Riboulet, Peter Dengel USPTO Applicaton #: 20070184741 - Class: 442327000 (USPTO) Related Patent Categories: Fabric (woven, Knitted, Or Nonwoven Textile Or Cloth, Etc.), Nonwoven Fabric (i.e., Nonwoven Strand Or Fiber Material) The Patent Description & Claims data below is from USPTO Patent Application 20070184741. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The present invention relates to novel non-woven fabrics, novel methods for producing non-woven fabrics and the use thereof in textile and technical applications. [0002] Textile surface structures have been known for quite some time. The techniques for producing these surface structures are subject to continuous improvements. [0003] For example, the loom is one of the oldest machines worldwide, yet to this day it is constantly being improved. While weaving speeds have been increased, among other things due to higher weft speeds, the process still means that the weft thread has to be lowered to a speed of zero on both sides of the textile fabric before it can resume its path in the opposite direction. [0004] Knitting is also a very old structure-forming technique, which can be carried out automatically. Knitting is a process of arranging each individual thread while being guided, or in the case of modern circular knitting machine also in a warp. [0005] Both methods described above share the fact that they use continuous threads as a semi-finished product. [0006] Further textile surface structures include felt and loden. Felt is obtained by fulling or needling several superimposed layers, particularly wool threads. A felt can also be considered as a fibrous web made of wool. Loden is initially woven from wool yarns, and the resultant wool fabric is then felted by means of fulling into the so-called loden material. Frequently, this involves the (often unintentional) tangling of the wool fibers due to straightening up scales. [0007] A further group of textile surface structures includes the non-wovens. These can be produced by wet or dry methods. [0008] During the production of wet non-wovens, short fibers are stirred in water that is heavily diluted and are separated from the water by a screen, whereupon they are mutually bonded chemically or thermally to form a non-woven fabric. A high dilution level in the water and a short fiber length ensure that the fibers of various origins neither become entangled nor can agglomerate with each other. This way, a very uniform distribution of the fibers across the surface can be achieved. The resultant surface structures, however, cannot withstand high mechanical loads. [0009] During the production of dry non-wovens, fibers with finite lengths are opened from the fiber bale that was prepared in a prior manufacturing stage, are likewise mixed with other types of fibers and are "combed" in a carding device in a preferred orientation, thus creating a card web. Several layers of this card web are placed on top of each other (stacked), wherein as a result of the depositing movements limited preferred orientations of the fibers are created and these layers are then converted into a non-woven vertically to the web plane by arbitrary bonding. This technique guarantees a high productivity as well as a high level of uniformity of the fiber deposition. By mixing the fibers, they can be adapted to desired surface structure properties within a broad range. In order to increase the mechanical stability, such as pilling or washing resistance, a high percentage of the intersecting points that are in contact with each other have to be chemically or thermally bonded into bonding sites. This increases the bending tensile strength, and the surface structure loses its draping ability. [0010] For the production of spunbound non-wovens, granules of one or more melt-spinnable polymers are melted in an extruder, pressed through a spinneret, mechanically or pneumatically extruded and placed on a belt. The non-bonded non-woven fabric is then mechanically stabilized analog to the aforementioned non-woven production methods. [0011] Until a few years ago, this method was used to produce surface structures, which were intended, for example, for applications as supports for sheet roofing or as supports for carpet fibers, and which were typically not subject to any demands in terms of textile drapeability. Unlike other non-wovens, spunbound non-wovens are characterized by a comparatively poor uniformity and the comparatively high mechanical loads they can be subjected to. [0012] Spun-bond equipment is characterized by a high productivity compared to other surface structure forming machines. This productivity, however, requires high investment costs and very high changeover times and cost when switching the polymers used. As a result of these factors, equipment of this type has to be operated with a certain lack of flexibility and has to be operated continuously. [0013] All non-woven fabrics share the common fact that the fibers forming their structure are stacked in several layers (placed in the x-y plane) and that the resulting mechanically unstable non-woven fabric then has to be consolidated in the z-direction. The chemical or thermal bonding method results in decreased drapeability. [0014] Compared to other textile surface structures, non-woven fabrics offer the advantage that the polymer granules or the fibers can be converted directly into the finished surface structure. When weaving or knitting, on the other hand, the yarns first have to be converted in the textile structure by a complex surface forming process. [0015] According to the related art, it has already been proposed to wind filaments after the production thereof and then introduce these products in a surface forming process. [0016] U.S. Pat. No. 3,921,265 and U.S. Pat. No. 3,885,279, for example describe a method for producing a non-woven fabric and a suitable device, wherein threads are deposited by several guide arms. They describe the directed depositing of the threads and not a non-woven forming process, which, as is known, is characterized by random deposition. In addition, they include no information as to the nature of the guided threads. [0017] DE patent 816 215 describes a device for producing fibrous mats or webs made of glass fibers or similar fibers. Several fibers are combined in a mechanical feeding means and placed on a surface in the form of coiled strands to form a web. The strands are fed by being transported by means of a blower. Depending on the adjustment of the blower, the feeding can be varied. Further details, particularly a random feeding of the strands, are not disclosed in this publication. The strands are maintained in the non-woven web. [0018] DE-A 30 12 806 describes a tufted carpet comprising a second backing made of continuous filament nonwoven with a plurality of layers of randomly laid threads made of polyester, which are disposed in a cross-over parallel texture. The nonwovens can also be produced in groups or by unwinding or removing polyester filaments and placing them jointly into a non-woven with a cross-over parallel texture. The use of non-melt spinnable fibers is not included in this document. [0019] DE-A 36 30 392 describes a method for producing consolidated nonwoven fabrics to absorb water and/or substances with oleophilic and/or lipophilic properties. The nonwoven is produced by direct blow-spinning on a device. [0020] EP-A,281,865 describes bound sheet-like structures made from organic fibers, such as water glass fibers or silicic acid fibers. The structure is obtained by directly processing the spun fibers by dry or wet techniques. The fibers are bonded by a heat treatment at temperatures above 50.degree. C. Due to the comparatively low bonding temperatures, the resultant fibers have to be processed promptly. [0021] From U.S. Pat. No. 5,660,910 nonwoven fabrics with improved tear resistance are known. Apart from matrix filaments, the nonwoven fabrics include reinforcement filaments with high titers. In addition to the production of spun-bond non-wovens, the patent also discloses the processing of previously spun and stored filaments into non-wovens. They are placed directly on a conveyor belt by means of a suction device. A random feeding of the stored filaments is not disclosed. The uniformity of the resultant non-woven fabrics is also limited due to the use of coarse filaments. [0022] DE-A 41 15 190 discloses nonwovens from filaments, which have a very uniform mass distribution, while at the same time achieving a high basis weight of more than 250 g/m.sup.2. For the production of these nonwovens, filaments (filament bundles) made of various materials are opened by air jets into single filaments, deposited very uniformly on to a moving surface and then bonded in the familiar fashion. Nonwovens with a low basis weight and uniform mass distribution are not disclosed there. Particularly these non-woven fabrics are difficult to produce since in the case of non-woven fabrics with high basis weights and a correspondingly high number of fibers per unit of volume, the developing irregularities are averaged out. Finally, exclusively thermoplastic spinnable materials are disclosed as fiber materials. [0023] Proceeding from the related art, it is the object of the present invention to provide non-woven fabrics with a very high level of uniformity. [0024] A subgroup of the novel non-woven fabrics relates to products, which comprises continuous threads that have not been able to be processed into non-woven fabrics so far. This way, the range of possible non-woven fabrics as well as the property profiles thereof and applications can be expanded. Continue reading... Full patent description for Non-woven fabrics and method for producing them Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Non-woven fabrics and method for producing them 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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