US 4,308,197 A · Fire resistant composites

Abstract

Highly fire resistant composites or laminates particularly applicable as structural components in aircraft, e.g. in the engine nacelle, as part of the acoustic panel-fire wall structure, and capable of withstanding a 2,000.degree. F. flame temperature, comprising incorporating an additive in the form of an ammonium salt, or an amine salt, of a phosphonic acid or a phosphinic acid, into a resin, e.g., a polyimide or an epoxy resin, such additive being soluble in the resin. The resulting resin containing the additive, e.g., the ammonium, or amine, salt of phenyl phosphonic or phenyl phosphinic acid, is then applied to or impregnated into a substrate such as glass fiber cloth or graphite fiber, to form a composite structure which is then cured. The resulting cured composite when subjected to high temperatures of the order of, e.g., a 2,000.degree. F. flame temperature, forms a resin char of reduced thermal conductivity which holds the fibers of the laminate together and maintains the structural stability and integrity of the laminate.

Claims27

Dependent claims

A fire resistant composition having low thermal conductivity, comprising a cured mixture of a resin selected from the group consisting of polyimide, epoxy, polybenzimidazole, polyquinoxyline, polyacrylate, phenolic and silicone resins;

and an additive consisting of an ammonium salt or an amine salt of a phosphonic or a phosphinic acid, said additive being soluble in said resin, and employed in an amount sufficient to form a stable resin char when said composition is heated to an elevated temperature sufficient to form said char, said ammonium or amine salt comprising a member selected from the group consisting of aliphatic, aromatic and heterocyclic substituted phosphonic and phosphinic acids.

A fire resistant composite having a low thermal conductivity, comprising a substrate selected from the group consisting of graphite fabric and glass fabric, impregnated with a composition comprising a cured mixture of a resin selected from the group consisting of polyimide, epoxy, polybenzimidazole, polyquinoxyline, polyacrylate, phenolic and silicone resin;

and an additive consisting of an ammonium or amine salt of a phosphonic or a phosphinic acid, said additive being soluble in said resin and employed in an amount sufficient to form a stable resin char when said composition is heated to an elevated temperature of the order of about 2,000.degree. F., said additive having the general formula from the group consisting of ##STR12## wherein X is OH;
OR or H;
Y is O or S;
R is a member selected from the group consisting of alkyl of from about 1 to about 6 carbon atoms, cycloalkyl of from about 5 to about 6 carbon atoms, aryl of from about 6 to 14 carbon atoms, and the corresponding halogenated alkyl and halogenated aryl derivatives, nitroaryl, heterocyclic, amino, and alkylamino containing about 1 to about 8 carbon atoms in the alkyl group, R' is selected from the group consisting of ammonia, monoalkylamino, dialkylamino, trialkylamino, monoarylamino, diarylamino, triarylamino, monocycloalkylamino, dicycloalkylamino, tricycloalkylamino, and heterocyclic amino, and R" is selected from the group consisting of hydrazine, guanidine, hydroxylamine and melamine.

1 more element

Dependencies are inferred from the claim text.

Fire resistant composites

Life of this patent

Fire resistant composites

Life of this patent

Abstract

Claims27