Patent ID: 7037970

Claim:
A process for increasing the melt strength of an ethylene-vinyl carboxylate copolymer composite extrudate, said composite having a melt index from 0.01 to 100 g/10 min and complex viscosity ratio at low frequency greater than 1.10, comprising: (a) preparing a concentrate by melt compounding 20 to 70 weight percent, based on the total weight of the concentrate, of a carrier resin selected from the group consisting of ethylene homopolymer and copolymers of ethylene and a comonomer selected from the group consisting of C 3-8 α-olefins, vinyl C 2-4 carboxylates, C 1-4 alkyl acrylates and C 1-4 alkyl methacrylates and 30 to 80 weight percent organically modified clay consisting of a smectite clay that has been ion-exchanged and intercalated with a dimethyl dihydrogenated tallow quaternary ammonium ion; (b) letting down the concentrate into an ethylene-vinyl C 2-4 carboxylate copolymer base resin at a ratio such that the composite contains 88 to 99.5 weight percent ethylene-vinyl carboxylate copolymer and 0.5 to 12 weight percent organically modified clay; (c) melt blending and extruding the composite.