VACUUM ASSISTED PROCESS TO MAKE CLOSED CELL RIGID POLYURETHANE FOAMS USING MIXED BLOWING AGENTS

摘要

Rigid polyurethane foam is made in a vacuum assisted process using a blowing agent mixture that includes water and hydrofluoroolefin and/or hydrofluorochloroolefin. In preferred embodiments, the blowing agent mixture further includes a hydro carbon such as cyclopentane.