Polymer foam and foam articles for fire protection

A method of forming a cellular polyurethane material comprising forming a mixture of a polyol component and an isocyanate component in the presence of inorganic components and foaming the composition to form a polyurethane foam, optionally in the presence of a blowing agent, wherein the inorganic components constitute in the range of from 20 to 60% by weight of the polyurethane foam composition and wherein the polyurethane foam composition comprises:

• an amount of polyol and isocyanate to provide at least 40% by weight based on the total weight of the polyurethane foam composition of a polyurethane;
• from 15% to 40% by weight based on the total weight of the polyurethane foam composition of a silicate mineral filler;
• from 5% to 20% by weight based on the total weight of the polyurethane foam composition of at least one inorganic phosphate that forms a liquid phase at a temperature of no more than 800° C.;
• and
• from 1% to 5% by weight based on the total weight of the polyurethane foam composition a heat expandable graphite;
• wherein the density of the polyurethane foam is in the range of from 150 to 500 kilograms per cubic meter.

A cellular polyurethane foam composition for forming a cellular ceramic under fire conditions, the composition comprising:

• at least 40% by weight based on the total weight of the composition of a polyurethane;
• from 15% to 40% by weight based on the total weight of the composition of silicate mineral filler;
• from 5% to 20% by weight based on the total weight of the composition of at least one inorganic phosphate that forms a liquid phase at a temperature of no more than 800° C.;
• from 1% to 5% by weight based on the total weight of the composition of expandable graphite;
• and
• wherein the total proportion of inorganic components constitutes in the range of from 20% to 60% by weight of the composition, the amount of silicate mineral filler is at least 50% by weight based on the total weight of inorganic filler content, the amount of at least one inorganic phosphate is at least one fourth by weight of inorganic filler content, and the density of the polyurethane foam is in the range of from 150 to 500 kilograms per cubic meter.