Phosphonitrilic Additives in Preparation of Fire-Resistant Resins

Abstract

The objective of this study was the development of PNC1₂ polymers or their derivatives to impart fire-retardance to four types of resins, namely polyesters, epoxy, polyurethane and phenolic resins. Reaction of PNC1₂ polymers with the resin matrices was accomplished demonstrating the feasibility of the concept. Linear PNC1₂ polymer of about 1100 molecular weight has been successfully formulated in polyesters containing an epoxy compound to scavenge HC1 which is formed. At 5 to 15% content of PNC1₂ a flame-retardant laminate (60% glass, Mil Spec 21607B) is produced with over 2MM psi flexural modulus. Both linear and cyclopolymers are useful in producing resin laminates which are self-extinguishing and of conventional strength. Fire-resistant laminates were prepared successfully using the four types of resins cited above.