Abstract:
A blowing agent for thermosetting foams is disclosed. The blowing agent is a hydrofluoroolefin (HCFO), preferably HFCO-1234ze in combination with a hydrochlorofluoroolefin (HCFO) preferably one selected from HCFO-1233zd, HCFO-1223, HCFO-1233xf and mixtures thereof. The blowing agent is effective as a blowing agent in the manufacture of thermosetting foams.