Nonwoven mechanicals

Within the plane of a nonwoven material, the fibers may be either completely isotropic or there may be a preferred fiber orientation or alignment usually with respect to a machine or processing direction. In the case of thicker dry-laid nonwovens, fiber orientation may be randomized in the third dimension, ie, that dimension which is perpendicular to the plane of the fabric, by a process known as needle-punching (7). This process serves to bind the fibers in the nonwoven by mechanical interlocking. 

Olefin fibers are used for a variety of purposes from home furnishings to industrial appHcations. These include carpets, upholstery, drapery, rope, geotextiles (qv), and both disposable and nondisposable nonwovens. Fiber mechanical properties, relative chemical inertness, low moisture absorption, and low density contribute to desirable product properties. Table 7 gives a breakdown of olefin fiber consumption by use (73—75). Olefin fiber use in apparel... 

A nonwoven fabric can be assembled by mechanically, chemically, or thermally interlocking layers or networks of fibers, filaments, or yams. Fabrics made from textile fibers in this manner have been classified as dry-laid nonwovens. 

Textile technology is used to mechanically or aerodynamicaHy arrange textile fibers into preferentially oriented webs. Fabrics produced by these systems are referred to as dry-laid nonwovens. Dry-laid nonwovens are manufactured with machinery associated with staple fiber processing, such as cards and gametts, which are designed to manipulate preformed fibers in the dry state. Also included in this category are nonwovens made from filaments in the form of tow, and fabrics composed of staple fibers and stitching filaments or yams, ie, stitchbonded nonwovens. 

Nonwoven bonding processes iatedock webs or layers of fibers, filaments, or yams by mechanical, chemical, or thermal means. The extent of bonding is a significant factor ia determining fabric strength, dexibiUty, porosity, density, loft, and thickness. Bonding is normally a sequential operation performed ia tandem with web formation, but it is also carried out as a separate and distinct operation. 

Adhesives and Sealants. Most industrial adhesives contain surface active components and additives, and air entrainment during their mechanical appHcation can significantly reduce joint strength. Defoamers are usually formulated into adhesives to protect users against such difficulties. Additional benefits, such as improved uniformity of products, increased throughput and reduced labor costs can also result from the use of defoamers during adhesive appHcation. The footwear and nonwoven fabric industries are extensive users of defoamers in this way. 

Fabric filtration, 26 706-713 mechanism of, 26 709 Fabrics. See also Spunbonded nonwoven fabrics Staple-fiber nonwoven fabrics chemical resistance and maximum temperatures of, 26 711t... 

Sony s Introduction of the rechargeable lithium-ion battery in the early 1990s precipitated a need for new separators that provided not only good mechanical and electrical properties but also added safety through a thermal shutdown mechanism. Although a variety of separators (e.g., cellulose, nonwoven fabric, etc.) have been used in different type of batteries, various studies on separators for lithium-ion batteries have been pursued in past few years as separators for lithium-ion batteries require different characteristics than separators used in conventional batteries. 

Ikoma et al. carried out a detailed investigation to study the self-discharge mechanism and contribution of separators.They used nonwoven fabric made of conventional polyamide (FA), FF (with surfactant), and a nonwoven fabric whose main material was sulfonated-FF (hydrophilic) as separators. When nonwoven fabric made of chemically stable sulfonated-FF is used as a separator instead of a conventional polyamide separator, the self-discharge rate of the NiMH battery was strongly depressed, to the same level as that of NiCd battery. 2 >o-242.243... 

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