Flame retardation of acrylic fibers: An overview

Protective clothing against thermal risks is required for many jobs in industry, in public enterprises, and in military applications. Statistical market research in 1996 for flame-retardant clothing material for western Europe indicated the consumption of 20 million m2. Acrylic fibers are used mainly in the decorating and home textile sectors in addition to the clothing sector, especially for knitted goods. These fields of application are becoming increasingly important in terms of flame-proofing regulations. This review, therefore, dealt with developments in flame retardation of acrylic fibers produced by various methods, for example, incorporation of comonomers like vinyl chloride or vinylidene chloride through copolymerization, using certain modifiers in the spinning dope or in the spinning bath, and surface modification, including finishing. Treatment of acrylic fibers with hydroxyl amine hydrochloride, hydrazine hydrate, or dibutyl tin ethyl maleate produces flame-retardant acrylics with an LOI > 30. Flame retardancy relates directly to char-forming tendency for all retardants and their ability to reduce the dominance of flammable volatiles formed during the first stage of acrylic fiber pyrolysis. In this context, ammonium phosphates have been found to be effective flame retardants. The possible mechnism of retardant activity was discussed, including the charforming tendency of antimony-bromine combinations. Copyright © 2000 by Marcel Dekker, Inc.