CERAMIC-COATED FIBERS INCLUDING A FLAME-RETARDING POLYMER, AND METHODS OF MAKING NONWOVEN STRUCTURES

Dimensionally-stable fibrous structures including ceramic-coated melt-blown nonwoven fibers made of a flame-retarding polymer and processes for producing such fire-resistant nonwoven fibrous structures. The melt-blown fibers include poly(phenylene sulfide) in an amount sufficient for the nonwoven fibrous structures to pass one or more fire-resistance test, e.g. UL 94 V0, FAR 25.853 (a), FAR 25.856 (a), and CA Title 19, without any halogenated flame-retardant additive, and have a ceramic coating. The melt-blown fibers are subjected to a controlled in-flight heat treatment at a temperature below a melting temperature of the poly(phenylene sulfide) immediately upon exiting from at least one orifice of a melt-blowing die, in order to impart dimensional stability to the fibers. The nonwoven fibrous structures including the in-flight heat-treated melt-blown fibers exhibit a Shrinkage less than a Shrinkage measured on a nonwoven fibrous structure including only fibers not subjected to the controlled in-flight heat treatment operation, generally less than 15%.