Novel Carbamylmethylated Melamine Polyols in Rigid Water-Blown Urethane Foams

Abstract

American Cyanamid Company has developed a novel, high functional carbamylmethylated melamine polyol named CYUNK™ HPC polyol. The reactivity of CYUNK™ HPC polyol was studied and compared with that of an aromatic amine polyol (Pluracol® 824 polyol) and a sucrose-based polyol (Voranol® 360 polyol). A combination of the CYUNK™ HPC polyol and aromatic amine polyol was used for the preparation of rigid urethane foams. Water, CFC-11A and a mixture of CFC-11A and water (50/50) were used as the blowing agents. The k-factor of the foams containing CYUNK™ HPC was good: 0.022 W/mK for the water-blown system, 0.018 for the foam blown with a mixture of CFC-11A and water, and 0.015 for the CFC-11A blown foam. In all cases, retention of the k-factor with ageing (at room temperature and 70°C) was better for foams containing CYLINK™ HPC than for the control foams. Photomicrographs of the cell structure showed that the cell size of the foams containing CYLINK™ HPC polyol was smaller than that of the control foams. The presence of CYLINK™ HPC polyol decreased the combustibility of the water-blown rigid urethane foams. This effect was very significant in the case of foams containing sucrose-based polyol. The residue after burning of the reference foam without flame retardant was 26%, and with flame retardant (10 pbw) 48%. The residue after burning of the foam containing 30 pbw of CYUNK™ HPC polyol without flame retardant was 76%. CYUNK™ HPC polyol can thus be classified as a reactive flame retardant**. The study also included the effect of surfactant concentration and isocyanate index on the properties of water-blown rigid urethane foams containing CYUNK™ HPC polyol.