To obtain a blowing agent lowly detrimental to the environment and useful as a blowing agent for e.g. polyurethane synthesis by selecting a (near)-azeotropic composition based on difluoromethoxybis(difluoromethyl ether) and/or 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ether.
This agent is a composition essentially consisting of a composition comprising a combination of 1-95 wt.% difluoromethoxybis(difluoromethyl ether) (HCF2OCF2OCF2H) with 99-5 wt.% n-pentane; of 1-93 wt.% 1- difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ether (HCF2OCF2CF2OCF2) with 99-7 wt.% n-pentane; of 1-60 wt.% HCF2OCF2CF2OCF2H) with 99-7 wt.% n-pentane; of 1-60 wt.% HCF2OCF2OCF2H with 99-40 wt.% dimethyl ketone; or of 15-99 wt.% HCF2OCF2CF2OCF2H with 85-1 wt.% hexane, or a like combination. It can be used as a substitute for trichlorofluoromethane in the field of foams.
BASILE GIAMPIERO
GIROLOMONI SAURO
