Textile industry: finishing unit

The largest commission finishers of fire-resistant textiles in the United stales tea 1995) are W extex and MF H Textiles. Inc. (Butler. Georgia). Specialized (lame-retardam applications to cotton-wrapped polyester. Kevlar, nylon, and glass core yams are beginning lo attract the interest of the industry for special-purpose fabrics. 

Half of the total energy consumption involved in the manufacture of finished textile fabrics is attributed to drying. Moreover, the textile industry in the United States is among the top ten industrial users of energy. Accordingly, it is... 

Methylation is no longer carried out with dimethyl sulfate, which was previously used. The resulting sodium chloride is rinsed away with water. The product is then spin-dried to a water content of 55-60% and subsequently homogenized and compacted in a screw extender. Ethyl cellulose is prepared in a manner analogous to that used for ethyl chloride and the reaction is taken to 2.1-2.6 ethoxy groups per glucose unit. The products serve as finishing materials in the textile industry as well as for paint bases and injection-molded articles. 

The National Occupational Exposure Survey (NOES), conducted from 1981 to 1983, indicated that 1,329,332 workers employed in various professions were potentially exposed to formaldehyde in the United States (NIOSH 1995b). The NOES database does not contain information on the frequency, concentration, or duration of exposure the survey provides only estimates of workers potentially exposed to the chemical in the workplace. OSHA has estimated that in the late 1980s over 2 million workers in over 112,000 firms were exposed to formaldehyde about 45% of these workers are estimated to be in the garment industry. About 1.9 million were exposed to levels of formaldehyde between 0.1 ppm and 0.5 ppm (mainly in apparel, furniture, paper mills, and plastic molding) approximately 123,000 were exposed to levels of formaldehyde between 0.5 and 0.75 ppm (mainly in apparel, textile finishing, furniture, laboratories, and foundries) and about 84,000 were exposed to between 0.75 and 1 ppm (mainly in apparel, furniture, and foundries) (OSHA 1996). 

Direct spinning is not very common for industrial yarns because there are only a few yarn types that would match the large capacity of polymerization units (> 25 000 ton y ). A further complication is that the polymer must be condensed to a high molecular weight, but this can be achieved in deep-vacuum, thin-film finishers . In most cases chips with a textile viscosity are solid-state postcon-densed, at a relatively low temperature (about 230°C), which takes many hours but has the advantage that thermal degradation is minimized. 

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