METHOD OF MAKING INSULATING RIGID POLYURETHANE FOAMS.

摘要

There is now provided a method for making a polyisocyanate based rigid closed cell foam made by reacting an organic isocyanate with a polyol composition made up of at least: a) an aromatic amine initiated polyoxyalkylene polyether polyol having an hydroxyl number of 200 meq polyol/g KOH or more; b) an aliphatic amine initiated polyoxyalkylene polyether polyol having an hydroxyl number of 200 meq polyol/g KOH or more in an amount of 10 weight percent or less based on the weight of the polyol composition; and c) cyclopentane, wherein the cyclopentane is dissolved in the polyol composition. The organic isocyanate and the polyol composition are reacted at an isocyanate index ranging from 80 to less than 150 and throughout this isocyanate index range, the resulting foam has a substantially constant k-factor and is dimensionally stable.