Process for melt extrusion of polymers
AssigneeE. I. DuPont de Nemours and Company
InventorsGeorge R. Chapman, Jr., Rita S. McMinn, Donnan E. Priester, William L. Phillips
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Abstract
Process of melt extruding through an extrusion die whose surface is coated with one or more metal oxides, M.sub.x O.sub.y, wherein M is a metal selected from the group consisting of Ti, Zr, Cr, Fe, Ni, Pd, Pt, Cu, Ag, Au, Al and Si, and x and y are selected to satisfy the valencies of M, a difficultly-melt-processible polymer containing 0.002-2 parts by weight, based on the weight of the polymer, of at least one melt-processible fluorocarbon polymer processing aid having a fluorine to carbon ratio of at least 1:2 and having metal oxide-reactive sites capable of reacting with or physically associating with the metal oxide of the die surface.
Claims53
A process comprising melt extruding through an extrusion die a composition comprising a difficultly-melt-processible polymer and 0.002-2% by weight, based on the weight of the difficultly-melt-processible polymer, of at least one melt-processible fluorocarbon polymer processing aid, said fluorocarbon polymer processing aid having a fluorine to carbon ratio of at least 1:2, wherein the die surface is coated with one or more metal oxides, M.sub.x O.sub.y, wherein M is a metal selected from the groups consisting of Ti, Zr, Cr, Fe, Ni, Pd, Pt, Cu, Ag, Au, Al and Si, and x and y are selected to satisfy the valencies of M, and wherein said fluorocarbon polymer processing aid has incorporated therein an effective amount of metal oxide-reactive sites capable of reacting with or physically associating with the metal oxide die surface.
Polymer extrusion die wherein the polymer-contacting die surface contains metal oxide M.sub.x O.sub.y, wherein M is a metal selected from the group consisting of Ti, Zr, Cr, Fe, Ni, Pd, Pt, Cu, Ag, Au, Al and Si, and x and y are selected to satisfy the valencies of M, and wherein M.sub.x O.sub.y has bonded thereto a fluoropolymer process aid.
A process for treating a polymer extrusion die surface, said process comprising incorporating into the polymer-contacting die surface a metal oxide M.sub.x O.sub.y wherein M is a metal selected from the group consisting of Ti, Zr, Cr, Fe, Ni, Pd, Pt, Cu, Ag, Au, Al and Si, and x and y are selected to satisfy the valence of M, and subsequently bonding thereto a fluoropolymer processing aid.
Dependencies are inferred from the claim text.