Flame retardant fiber blend containing fibers which if present apart from the admixture undergo burning

A flame retardant admixture of fibers comprising:

• (a) discrete fibers which if present apart from said admixture undergo burning when subjected to a methane diffusion flame in an oxygen-containing gaseous atmosphere having an oxygen content selected from within the range of about 20 to 40 percent by volume, and
• (b) discrete polyester fibers of a synthetic chlorinated or brominated aromatic polymer having the recurring structural formula:
• ##STR4## where X is chlorine or bromine, Y is hydrogen, chlorine or bromine, R and R' may be the same or different and represent lower alkyl groups, hydrogen, or together constitute a cyclic hydrocarbon group, and n= at least 25, and a chlorine and/or bromine content of about 25 to 50 percent by weight based upon the weight of said aromatic polyester capable of rendering said admixture as a whole non-burning when subjected to said flame in said oxygen-containing gaseous atmosphere of the same oxygen content.

A flame retardant admixture of fibers exhibiting satisfactory textile properties which is non-burning when subjected to an ordinary match flame at ambient conditions comprising:

• (a) about 20 to 90 percent by weight of discrete fibers which if present apart from said admixture undergo burning when subjected to an ordinary match flame at ambient conditions, and
• (b) about 10 to 80 percent by weight of discrete aromatic polyester fibers formed from the reaction of tetrabromobisphenol A, and a mixture of about 45 to 75 percent by weight isophthalic acid and correspondingly about 55 to 25 percent by weight terephthalic acid or the ester-forming derivatives thereof having a bromine content of about 48 percent by weight and having intimately dispersed therein about 0.1 to 10 percent by weight based upon the weight of said aromatic polyester of an oxide of antimony, with said discrete fibers of component (b) being capable of rendering said admixture as a whole non-burning when subjected to an ordinary match flame at ambient conditions.

A process for rendering discrete fibers flame retardant which have a propensity to undergo burning when subjected to a methane diffusion flame in an oxygen-containing gaseous atmosphere having an oxygen content selected from within the range of about 20 to 40 percent by volume comprising intimately blending in physical admixture therewith discrete fibers of a synthetic aromatic polymer containing chlorine, bromine, or mixtures thereof chemically bound to an aromatic ring having a chlorine and/or bromine content of about 25 to 50 percent by weight based upon the weight of said aromatic polymer and the inherent ability to render said admixture as a whole non-burning when subjected to said flame in said oxygen-containing atmosphere of the same oxygen content.

A process for enhancing the flame resistance of discrete fibers comprising intimately blending in physical admixture therewith discrete fibers of a synthetic chlorinated or brominated aromatic polymer having a chloride and/or bromine content of about 25 to 50 percent by weight chemically bound to an aromatic ring.

A process for rendering discrete fibers flame retardant which undergo burning when exposed to a methane diffusion flame in an oxygen-containing gaseous atmosphere having an oxygen content selected from within the range of about 20 to 40 percent by volume comprising intimately blending in physical admixture therewith discrete fibers of a chlorinated or brominated aromatic polymer having the recurring structural formula:

• ##STR5## where X is chlorine or bromine, Y is hydrogen, chlorine or bromine, R and R' may be the same or different and represent lower alkyl groups, hydrogen, or together constitute a cyclic hydrocarbon group, and n= at least 25 and a bromine and/or chlorine content of about 25 to 50 percent by weight based upon the weight of said aromatic polymer capable of rendering said admixture as a whole non-burning when subjected to said flame in said oxygen-containing atmosphere of the same oxygen content.

A process for rendering discrete fibers non-burning which undergo burning when exposed to an ordinary match flame comprising intimately blending in physical admixture therewith discrete aromatic polyester fibers formed from the reaction of tetrabromobisphenol A, and a mixture of about 45 to 75 percent by weight isophthalic acid, and correspondingly about 55 to 25 percent by weight terephthalic acid or the ester-forming derivatives thereof having a bromine content of about 48 percent by weight and containing intimately dispersed therein about 0.1 to 10 percent by weight of an oxide of antimony based upon the weight of said aromatic polyester, with said resulting admixture as a whole being non-burning when subjected to an ordinary match flame.