초록 ▼

The use in conventional polyolefin extrusion foaming processes of a stability control agent (e.g., stearamide, EAA copolymer, etc.) in conjunction with certain mixed blowing agent systems, the mixed blowing agent system containing 60-95 weight percent of 1-chloro-1,1-difluoroethane or 60-95 weight p

The use in conventional polyolefin extrusion foaming processes of a stability control agent (e.g., stearamide, EAA copolymer, etc.) in conjunction with certain mixed blowing agent systems, the mixed blowing agent system containing 60-95 weight percent of 1-chloro-1,1-difluoroethane or 60-95 weight percent of 1,1-difluoroethane. These compounds have a shorter atmospheric lifetime and lower stability than the saturated chlorofluorocarbons presently used as blowing agents or in blowing agent systems.

대표청구항 ▼

A process for preparing closed-cell olefin polymer foamed articles having increased maximum achievable cross-sectional areas and having good dimensional stability which process comprises the steps of: (A) heat plastifying a normally solid olefin polymer resin; (B) admixing said heat plastified resin

A process for preparing closed-cell olefin polymer foamed articles having increased maximum achievable cross-sectional areas and having good dimensional stability which process comprises the steps of: (A) heat plastifying a normally solid olefin polymer resin; (B) admixing said heat plastified resin under elevated temperature and pressure with (1) a stability control agent and (2) a mixed blowing agent system selected from the group consisting of (a) from about 50 to about 95 weight percent of 1-chloro-1,1-difluoroethane and from about 5 to about 50 weight percent of an aliphatic hydrocarbon composition and/or a halogenated hydrocarbon composition, such composition(s) having a normal atmospheric boiling point of from about 0°C. to about 50°C., the system having a saturated vapor pressure at 100°C. of less than about 21 kg/cm2 but greater than about 17kg/cm2; and (b) from about 50 to about 95 weight percent of 1,1-difluoroethane and from about 5 to about 50 weight percent of an aliphatic hydrocarbon composition and/or halogenated hydrocarbon compositions, such aliphatic and/or halogenated hydrocarbon composition(s) having a normal atmospheric boiling point of from about 0°C. to about 50°C., the system having a saturated vapor pressure at 100°C. of less than about 32 kg/cm2 but greater than about 24 kg/cm2; the weight percentages of the components in the mixed blowing agent systems being based on the total weight of the mixed blowing agent system, (C) extruding the resultant resin, stability control agent and blowing agent mixture into a zone of lower pressure; and (D) cooling the mixture to thereby form an olefin polymer foam.