Nonwoven fabrics nonwovens

Nonwoven manufacturing, cotton, 3 18 Nonwoven materials, 24 620. See also Nonwoven fabrics Nonwoven processes, 17 496-497 Nonwovens. See also Nonwoven fabrics air-laid, 17 503 defined, 17 495-496 foam-bonded, 17 510 needled, 17 506, 507 thermal-bonded, 17 511-512 Nonwoven textile materials, 11 178-180 4-Nonylphenol (PNP), 2 225-226 health and safety data, 2 220t physical properties of, 2 205t Nonyl phenol, 10 429 8-Nonynoic acid, 5 34t... 

Bonding methods -nonwoven fabrics [NONWOVEN FABRICS - STAPLE FIBERS] (Vol 17) -in spunbonded manufactunng [NONWOVEN FABRICS - FABRICS,SPUNBONDED] (Vol 17)... 

As binders for fiherfill and nonwovens, the emulsions are applied to a loose web or mat, then heated to form a film that sticks the loose fibers together. Polyester (188—191), glass (192), and rayon (193) mats are bonded in this manner for a variety of end uses including quilting, clothing, disposable diapers and towels, filters, and roofing (see Nonwoven fabrics). 

D. I. Lunde, Nonwoven Fabrics Forum, Clemson Univ.,June 15—17, 1982. 

Fig. 2. Scanning electron photomicrograph of a polyester nonwoven fabric.

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. 

Typical textile fibers have linear densities in the range of 0.33—1.66 tex (3 to 15 den). Fibers in the 0.33—0.66 tex (3—6 den) range are generally used in nonwoven materials as well as in woven and knitted fabrics for use in apparel. Coarser fibers are generally used in carpets, upholstery, and certain industrial textiles. A recent development in fiber technology is the category of microfibers, with linear densities <0.11 tex (1 den) and as low as 0.01 tex. These fibers, when properly spun into yams and subsequendy woven into fabrics, can produce textile fabrics that have excellent drape and softness properties as well as improved color clarity (16). 

Textiles. A unique combination of desirable quaUties and low cost accounts for the demand for acetate ia textiles. In the United States, acetate and triacetate fibers are used ia tricot-knitting and woven constmctions, with each accounting for approximately half the total volume. This distribution changes slightly according to market trends. The main markets are women s apparel, eg, dresses, blouses, lingerie, robes, housecoats, ribbons, and decorative household appHcations, eg, draperies, bedspreads, and ensembles. Acetate has replaced rayon filament ia liner fabrics for men s suits and has been evaluated for nonwoven fabrics (79—81). 

Texturing. The final step in olefin fiber production is texturing the method depends primarily on the appHcation. For carpet and upholstery, the fiber is usually bulked, a procedure in which fiber is deformed by hot air or steam jet turbulence in a no22le and deposited on a moving screen to cool. The fiber takes on a three-dimensional crimp that aids in developing bulk and coverage in the final fabric. Stuffer box crimping, a process in which heated tow is overfed into a restricted oudet box, imparts a two-dimensional sawtooth crimp commonly found in olefin staple used in carded nonwovens and upholstery yams. 

Several more recent variations of the film-to-fiber approach result in direct conversion of film to fabric. The film may be embossed in a controlled pattern and subsequently drawn uniaxiaHy or biaxiaHy to produce a variety of nonwoven products (47). Addition of chemical blowing agents to the film causes fibrillation upon extmsion. Nonwovens can be formed directly from blown film using a unique radial die and control of the biaxial draw ratio (48)... 

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