Patent ID: 7179413

Claim:
A process for the preparation of plexifilamentary film-fibril strands of synthetic fiber-forming polymer which comprises generating a spin fluid consisting essentially of (a) 5 to 30 wt. % of a synthetic fiber-forming polymer, (b) a primary spin agent selected from the group consisting of hydrocarbons with 4 to 7 carbon atoms, and chlorinated, brominated and fluorinated compounds, and (c) a co-spin agent selected from the group consisting of fluorinated organic compounds containing 4 to 8 carbon atoms and a double bond, and having an atmospheric boiling point of less than 100° C., said co-spin agent being present in the spin fluid in an amount sufficient to raise the cloud point pressure of the spin fluid by at least 345 kPa; and flash-spinning the spin fluid at a pressure that is greater than the autogenous pressure of the spin fluid into a region of lower pressure to form plexifilamentary film-fibril strands of said synthetic fiber-forming polymer.