1,1,1,2-Tetrafluoroethane as the Primary Blowing Agent for Rigid Polyurethane Foams Using Conventional Foam Mixing Equipment

In previous reports we have shown that chlorodifluoromethane (HCFC-22) can be used in liquid resin systems as the primary blowing agent for polyurethane foams. We have now found that the same techniques pioneered using HCFC-22 can be used to run foam systems blown by HFC-134a on conventional foam equipment. Like HCFC-22, HFC-134a can be dissolved into the resin. Using both sucrose and amine initiated polyols, foams have been made with densities dawn to 1.4 PCF. HFC-134a levels up to 25 weight percent of the resin have been run, without significant modification, on conventional polyurethane foam equipment. The HFC-134a blown foams have good closed cell structure, good dimensional stability, low density, and in general, good physical properties