Foaming system for rigid urethane and isocyanurate foams based on polyethers and aromatic polyester polyols

摘要

Improved fluorocarbon blowing agents composed of blends of (a) CFC-11, trichlorofluoromethane, with (b) CFC-123 or CFC-123a, dichlorotrifluoroethane, have been found which impart significant improvement in the solubility characteristics of rigid urethane foam systems that contain significant amounts of aromatic polyester polyols. A substantial increase in the solubility of the CFC-11/CFC-123 or CFC-11/CFC-123a blends over CFC-11 alone in typical rigid urethane foam premix systems containing variable concentrations or aromatic polyester polyol is obtained. Preparation of rigid urethane foams have shown that improved solubility CFC-11 blends with CFC-123 or CFC-123a permit an increase in the amount of aromatic polyester polyol than can be used in the formulation without any significant differences in the physical characteristics of foams compared to those produced from CFC-11 without inclusion of aromatic polyester polyols.