Submitted to: Handbook of fire resistant textiles
Publication Type: Book / chapter
Publication Acceptance Date: 11/25/2012
Publication Date: 4/1/2013
Citation: Cardamone, J.M. 2013. FR wool and wool blends. Handbook of fire resistant textiles. No. 140. Interpretive Summary:
Technical Abstract: Wool is naturally flame retardant. It does not ignite easily, burns with a self-extinguishing flame, and forms a soft dissipating ash residue when synthetic fibers form a hard, molten bead residue with melt-drip behavior. Wool is preferred for it presents fewer hazards for industrial and military uses in furnishings and apparel. Many and varied chemistries had been investigated and developed during 1950 to 1980 for improving the fire performance of wool fibers. They include zirconium, phosphonate, halogenated compounds, generally applied by exhaust similar to conventional mordant dyeing. Increasing commercial demands in terms of cost-effectiveness coupled with increasing concerns for the environmental and general toxicological character of these materials and treatments have led to including high performance (HP) heat resistant fibers in wool blended yarns and fabrics. Limitations for this use include negative impact on fabric hand, resistance to dyeing, and high cost, as well as loss of the salient comfort properties of wool relative to the blend percentage of the HP fiber. A novel HP polyimidesiloxane (PISi) was synthesized by Cardamone and Kanchagar (US Patent 7264637, 2007-Sep.-4) for application to all-wool fabrics. Burning inhibition of PISi-treated wool as measured by char length, matched that of fabric blended of 50% wool, 48% Nomex®, 1% Kevlar®, 1% conducting fiber but PISi-treated wool was superior in maintaining a dissipating ash residue. A survey is provided of conventional and modern approaches to improving FR of wool and wool blends.