Patent ID: 7005458

Claim:
A method for making a flexible polyurethane foam, comprising: mixing at a mix head to react (i) a polyether graft polyol or a polyether graft polyol mixed with an ester polyol and/or a polyether polyol, wherein said polyol or combination of polyols has a number average molecular weight of from about 500 to about 8000, with (ii) an isocyanate selected from the group consisting of diphenylmethane 4,4′ diisocyanate, diphenyl methane 2,2′ diisocyanate, diphenylmethmne 2,4′ diisocyanate, toluene diisocyanate, higher molecular weight isocyanate oligomers, and mixtures thereof, with an isocyanate index in the range of 95 to 110 to form a reaction mix; incorporating into the reaction mix water in an amount from 0.2 to 1.0 parts by weight per hundred parts polyol; further incorporating into the reaction mix one or more anti-static additives in an amount from 0.1 to 20 parts by weight per hundred parts polyol, to form a foam-forming mixture; and presenting the foam-forming mixture to an open container or a moving conveyor to permit free rise expansion of the polyurethane foam; wherein, upon curing, the polyurethane foam has a density in the range of 6 to 20 pounds per cubic foot, a surface resistivity below 1×10 11 ohms/square as determined at 12% relative humidity and 23° C., and a pore size in the range of 100 to 250 pores per inch.