Patent ID: 7238730
Filing Date: 2007-07-03
Classification: C08G

Abstract:
1. A viscoelastic polyurethane foam comprising a reaction product of: an isocyanate component substantially free of toluene diisocyanate and comprising pure diphenylmethane diisocyanate in an amount of from 50 to 99 parts by weight based on 100 parts by weight of said isocyanate component and polymeric diphenylmethane diisocyanate in an amount from 1 to 50 parts by weight based on 100 parts by weight of said isocyanate component, an isocyanate-reactive blend comprising, a first isocyanate-reactive component having a weight-average molecular weight of from 2500 to 4500, a hydroxyl number of from 30 to 50, and comprising at least 60 parts by weight of ethylene oxide based on 100 parts by weight of said first isocyanate-reactive component, and a second isocyanate-reactive component having at least three isocyanate-reactive groups, a weight-average molecular weight of from 1000 to 6000, a hydroxyl number of from 20 to 500, and comprising at most 30 parts by weight of ethylene oxide based on 100 parts by weight of said second isocyanate-reactive component, wherein said first isocyanate-reactive component is used in an amount of from 40 to 75 parts by weight and said second isocyanate-reactive component is used in an amount of from 25 to 60 parts by weight, both-based on 100 parts by weight of said isocyanate-reactive blend; a chain extender having a weight-average molecular weight of from 25 to 250 and having a backbone chain with from two to eight carbon atoms and having two isocyanate-reactive groups, wherein said chain extender is used in an amount of from 5 to 30 parts by weight based on 100 parts by weight of said foam; and wherein said foam has a glass transition temperature of from 5 to 65 degrees Celsius and a tan delta peak of from 0.75 to 1.75; and wherein said foam has a density of greater than two and a half pounds per cubic foot and is substantially free of flame retardant and passes California Technical Bulletin 117-Flammability test as a result of said isocyanate component and said isocyanate-reactive blend.