| abstract |
A fire retarded polymer composition is disclosed, which comprises a polymer component, at least one halogen-containing fire retardant and a heat expandable graphite. The polymer component is selected from among polystyrenes, polyesters and polyolefins. The halogen of the fire retardant is bromine or chlorine. , and the total amount of the fire retardant and the heat expandable graphite is from about 6.5 to about 40% by weight. The composition may also contain a metal oxide fire retardant, such as antimony trioxide, but if so, it contains it in amounts much lower than those required in prior art compositions to achieve the same degree of fire retardancy. It is preferred that the heat expandable graphite be such as to expand 50 times or more on shock heating from room temperature to 900oC. The process by which the expandable graphite is produced is not critical, and it is known, for example, to pro duce it by oxidation of natural or artificial graphite. |