RIGID POLYURETHANE FOAMS AND METHOD TO FORM THESE FOAMS USING DIOLES AND TRIOLS OF LOW MOLECULAR WEIGHT.

摘要

A polyurethane foam, comprising the reaction product of a first reactant comprised of a polyisocyanate having an average isocyanate functionality greater than 2 and a second reactant comprised at least 10 weight percent, based on the weight of the second reactant, of a low molecular weight compound having at least two and less than three groups containing an active hydrogen, and having a molecular weight of at most 200, optionally an auxiliary polyol having a molecular weight of at least 300, a number of hydroxyl of 20 to 1000, which has a chain length and functionality such that it does not crosslink the foam in a way that affects the stiffness of the foam, and water, in which the reaction product is formed in the absence, or in presence of trace amounts of a crosslinker polyol having a functionality greater than three and a molecular weight of 300 to 800, in which the polyurethane foam is closed cell, does not deform elastically It only has a density of 80 to 800 kilograms per cubic meter, in which the first reactant and the second reactant are contacted at a volume ratio of the first reactant to the second reactant of 0.7 to 1.3.