Nonwoven materials

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). 

Nonwoven materials have not been able to compete with microporous films, most probably because of the difficulty in mak ing thin (25pm) nonwovens with acceptable physical properties (for example,... 

Long-term exposure can be stopped using either soil or a nonwoven fabric to cover the membrane in a surface impoundment. Another option is to drape a heavy, nonwoven fabric with base anchors in it over the membrane. This nonwoven material is cheaper, safer, and more readily repaired than a soil cover. 

Foam compositions, including a latex and a polynitrile oxide such as 2,4,6-triethylbenzene-l,3-dicarbonitrile oxide, or a latex and an epoxy silane, or a latex and a mixture of the two crosslinkers have been prepared (526). The compositions may also contain additional components, including fillers, surfactants, cell detackifiers, froth stabilizers, froth boosters, viscosity reducers, and compounds to improve resilience, and antioxidants. The compositions are particularly useful in the manufacture of flooring, wall covering, shoe lining and nonwoven materials. 

Nonwoven cards, 17 499-500 Nonwoven fabrics, See also Nonwoven materials Nonwovens Nonwoven textile materials global demand for, 17 483t spunbonded, 17 460—494 staple-fiber, 17 495-518 Nonwoven finishing processes,... 

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... 

The islands-in-the-sea approach uses bico technology to extrude filaments that contain a multiplicity of small fibrils encased in a soluble matrix. After fiber processing and fabric formation, the matrix is dissolved away to leave behind the microfibers. Fibers with sub-micron diameters can be produced. The process is expensive, but luxurious fabrics and nonwoven materials such as Ultrasuede are made in this way. 

Nonwoven materials have also been developed for lithium-ion cells but have not been widely accepted, in part due to the difficulty in fabricating thin materials with good uniformity and high strength. Nonwoven separators have been used in button cells and bobbin cells when thicker separators and low discharge rates are acceptable. 

Nonwoven materials such as cellulosic fibers have never been successfully used in lithium batteries. This lack of interest is related to the hygroscopic nature of cellulosic papers and films, their tendency to degrade in contact with lithium metal, and their susceptibility to pinhole formation at thickness of less than 100 fjim. For future applications, such as electric vehicles and load leveling systems at electric power plants, cellulosic separators may find a place because of their stability at higher temperatures when compared to polyolefins. They may be laminated with polyolefin separators to provide high-temperature melt integrity. 

We will now discuss some examples where NIR spectroscopic imaging has been used to evaluate some materials of commercial interest. This will include examples from a variety of home/commercial product areas including fabric wetting, spray deposition, food composition and surfactant deposition on nonwoven materials. These examples will demonstrate both qualitative and quantitative uses of NIR spectral imaging for determining chemical distributions in nonhomogeneous materials. 

Dal Pra, I., Freddi, G., Minic, J., Chiarini, A., and Armato, U. "De novo engineering of reticular connective tissue in vivo by silk fibroin nonwoven materials". Biomaterials 26(14), 1987-1999 (2005). 

INDA, the Association of the Nonwoven Fabrics Industry, has published repellency test methods specifically designed for the nonwoven fabric structure. 1ST 80.5(01/ is designed to measure a nonwoven material s abihty to resist gravity-only penetration by a saline solution. This property is useful in assessing the degree of water repeUency needed by nonwovens in a number of applications. A sample of the nonwoven to be tested is placed in the mouth of a quart size Mason jar containing saline solution. The jar is then inverted and placed on an electric grid that senses when the solution has penetrated the nonwoven. The time to complete penetration is recorded as a measure of repellency. 

A nonwoven material, for example, would be a felt. They are pads of short nonrandom fibers, made of rigid constmction suitable for many types of filtration equipment. 

A practicable reextrusion process was worked out and described by Syntex Chemie nearly forty 30 years ago [23]. This method—with some modifications—is still being used. The greatest recycler of fiber waste in the U.S. is Wellman they recover PET fiber and bottle waste for home furnishing and nonwoven materials by a similar method. 

Significant advances have been made in recent years in the packaging of medical products requiring medium and high barrier protection. The demand for sterilizable packaging for hospitals and industry is being met by special paper, plastic films, and other nonwoven materials. 

Radetic, M.M., Jocic, D.M., Jovancic, P.M., Petrovic, Z.L., Thomas, H.F., 2003. Recycled wool-based nonwoven material as an oil sorbent. Environmental Science and Technology 37, 1008-1012. 

Radetic, M., Ilic, V., Radojevic, D., Miladinovic, R., Jocic, D., Jovancic, P., 2008. Efficiency of recycled wool-based nonwoven material for the removal of oils from water. Chemosphere 70, 525-530. 

Schmack et al. [126] spun PLA fibers through the reactive extrusion polymerization of L-lactide (92 wt%) and meso-lactide (8 wt%). In many potential textile technological applications (e.g., for nonwoven materials) the fiber forming process is of general importance. An effective polymer synthesis requires also an effective spinning process to reduce the still high cost of the PLA fibers compared with those of established synthetic fibers. 

Chem. Descrip. Acrylic disps. and emulsions Uses Binder for decorative paints, adhesives, textiles and nonwoven materials, leather, pulp/paper, etc. 

It may be concluded that natural cellulose has a complicated multilevel struc-mral organization. The linear cellulose macromolecules joined by hydrogen bonds form the nanocrystaUites, NCD, and elementary nanofibrils. The elementary nano-fibrils are aggregated into microfibrils, which form lamellas and layers of the cell wall of natural cellulose fibers, and the fibers are constituents of various cellu-losic materials papers, textiles, nonwoven materials, etc. 

Nonwoven materials are used extensively for drapes and cover cloths and are composed of films backed on either one side or both sides with nonwoven fabrics. The film is completely impermeable to bacteria while the nonwoven backing is highly absorbent to both body perspiration and secretions from the wound. Hydrophobic finishes may also be applied to the material in order to achieve the required bacteria barrier characteristics. The developments in surgical drapes have led to the use of loop-raised, warp-knitted polyester fabrics that are laminated back to back and contain micropo-rous PTFE films in the middle for permeability, comfort, and resistance to microbiological contaminants. 

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