Flame Retardant Treatment and Inherently FR Synthetic Fibres
topic
Flame retardant (FR) treatment of synthetic fibres addresses their characteristic burning behaviours — polyester melts and drips (Tm 258°C, ignition temperature 450°C, LOI 20–21% — burns without applied flame after ignition); nylon 6 melts and drips (Tm 220°C, LOI 20–21%); polypropylene melts and flows (Tm 163°C, LOI 18% — most flammable, burning droplets); acrylic chars without melting (LOI 18–20%, dense acrid smoke) — requiring FR treatment for upholstery, sleepwear, children's apparel, military, and technical applications. FR treatment mechanisms on synthetic fibres: halogen-based (decabromodiphenyl ether DeBDE — EU REACH restricted since 2008; Dechlorane Plus — still permitted); phosphorus-based (reactive: organophosphorus comonomer incorporated into PET chain during polymerisation — Trevira CS PET copolymer with phosphonate comonomer 0.6 mol%, LOI increases 20.5% → 28%, permanent FR, no wash-off); additive nitrogen-phosphorus synergist (Exolit OP 1312, Clariant, 15–20% in PET matrix — melt-compounded masterbatch, 20% → 26% LOI); intumescent systems (melamine cyanurate + ammonium polyphosphate, swells to char on heating). Inherently FR synthetic fibres: Trevira CS (Hoechst/Trevira, DE-phosphorus copolyester, LOI 28–32%, EU and US Furniture Flammability Standard EN 1021-1 and Cal. TB 117A compliant) — contract upholstery; meta-aramid Nomex (Tg 265°C, no melting, LOI 28–32%, inherently FR) — firefighter turnout; PBI polybenzimidazole (LOI 41%, decomposes >600°C) — highest FR performance commercial textile, $80–120/kg; modacrylate fibre (acrylonitrile copolymer with vinyl chloride or vinylidene chloride 35–45% halogen by weight, LOI 26–30%) — contract upholstery, children's sleepwear (self-extinguishing). FR testing standards: BS 5852 (UK furniture, cigarette and match test); EN 1021-1 (EU furniture, smouldering cigarette); NFPA 701 (USA drapery); EN ISO 11611 (welding protective clothing); EN 469 (firefighter protective clothing Level 1/2). Microplastic concern: FR-treated synthetic fibre garment washing releases FR-coated microplastic particles with adsorbed toxic FR chemicals — active research area for reduced microplastic emission FR systems.
Role
Flame retardant treatment of synthetic fibres is the mandatory compliance requirement for the entire contract upholstery, children's sleepwear, military, and industrial protective clothing markets — with Trevira CS copolyester incorporating phosphorus FR comonomer into the polymer chain achieving permanent LOI 28–32% that satisfies EN 1021-1 furniture flammability throughout the 15-year service life of upholstery fabric without the wash-durability limitations of surface-applied FR finishes, making inherently FR synthetic fibres the quality standard against which all treated FR solutions are benchmarked in safety-critical applications.