Patent ID: 7919190

Claim:
An intumescent composition, comprising: (A) at least one halogen-free polymer, the polymer exhibiting a glass transition temperature (Tg) of from −20 to 10° C. and a total loss of mass of at least about 7% by weight at a temperature of 370° C. when subjected to thermogravimetric analysis and which comprises at least one copolymer derived from a mixture of monomers comprising i) styrene and ii) alkyl acrylate the weight ratio of i) to ii) being in the range from 0.05:1 to 2:1; (B) at least one acid source selected from ammonium polyphosphate, mono-ammonium orthophosphate, diammonium orthophosphate, condensed phosphoric acid, orthophosphoric acid, or a mixture of two or more thereof; (C) at least one carbon-yielding source selected from i) pentaerythritol, dipentaerythritol, tripentaerythritol, or a mixture of two or more thereof, or ii) carbohydrate modified sugar, carbohydrate modified starch, water-dispersible protein, gelatin, casein, or a mixture of two or more thereof; and (D) at least one blowing agent selected from melamine, melamine salt, urea, dicyandiamide, or a mixture of two or more thereof, said intumescent composition characterized by its ability to form a protective carbonaceous char layer exhibiting enhanced fire retardant properties when said intumescent composition is exposed to fire.