Fire retardant mixture for protection of suitable composite products

A plastic foam product having dispersed therein fire retarding materials, said fire retarding materials comprising

• a known carbon base intumescent material which produces a protective cellular foam layer when exposed to combustion temperatures, and
• a vitrifying agent which locks the intumescent cellular foam layer when exposed to a temperature sufficient to activate said vitrifying agent.

A fire retarding mixture to be added to a suitable composite product of predetermined shape comprising;

• a known carbon base intumescent material which when exposed to heat of combustion produces a protective cellular foam layer;
• and a vitrifying agent which locks the intumescent protective layer when exposed to a temperature which would otherwise cause decomposition of the foamed intumescent, said vitrifying agent locks the intumescent protective layer by vitrifying and combining therewith to form an enhanced protective layer.

A method of forming a two stage fire retarding surface layer of a product when exposed to the heat of combustion comprising;

• forming an initial intumescent cellular foam layer on a product from intumescent material contained within the product and exposed to the surface of the product as the product is partial consumed by combustion and,
• vitrifying a vitrifying agent within said foam layer at a temperature less than the temperature at which said intumescent layer decomposes, said agent being originally within said product and accumulating at the surface of the product as the product is partially consumed, said agent locking the said intumescent cellular foam layer.

A method of producing a fire retardant plastic foam product comprising;

• mixing with the polymer resin and blowing agent,
• a known carbon based intumescent foaming material such that said intumescent is dispersed throughout the foam product and a known vitrifying material of the type suitable for a fire protection layer when vitrified, said vitrifying material being dispersed throughout the foam product, said product, when exposed to the heat of combustion, collapsing at the surface thereof causing a surface accumulation of intumescent and vitrifying material, the accumulated intumescent material, when exposed to a temperature of about 200.degree. C., producing a cellular foam layer which provides a first stage of fire protection for the foam product, the accumulated vitrifying material vitrifying after substantial formation of said cellular foam layer, resulting in said layer and said vitrifying agent forming a stable insulating layer which renders said product less combustible than an untreated product.