Foaming synthetic resin compositions stabilized with certain higher ethers, esters or anhydrides

Claim 1

An extrusion foaming process for expanding an aliphatic olefin polymer which comprises (1) heating plastifying said olefin polymer; (2) admixing said heat plastified olefin polymer under conditions of elevated temperature and pressure with a volatile organic blowing agent and with from 0.1 to 10 weight percent based upon said olefin polymer of a compound of the formula I: R.sub.1 --X--R.sub.2 (I) wherein R 1 and R 2 represent an aliphatic hydrocarbon group having 3 to 24 carbon atoms, respectively, with at least one thereof having 10 or more carbon atoms, and X represents a radical selected from the group consisting of ##STR2## (3) extruding the resultant heat plastified mixture into a zone of lower pressure to thereby produce an aliphatic olefin polymer foam product.