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US 4,731,216 AGranted
Process for manufacturing a seamless laminar article
AssigneeE. I. Du Pont de Nemours and Company
InventorAlvin S. Topolski
Life of this patent
Estimating the term…
Abstract
Seamless, molded, thermoplastic articles having a laminar, multi-component composition with a heterogeneous blend of incompatible polymers--at least one as a matrix and at least one as a discontinuous phase, are manufactured by (1) heating the blend above the melting point of the highest melting polymer component, and (2) molding the melted blend to have a knit line curved through the thickness of the article resulting from such molding.
Claims9
A process for manufacturing a laminar, molded, hollow, article of polymeric material comprising the steps of:
- (i) establishing a molten, heterogeneous, blend of a first polymer component and a second polymer component imcompatible with the first by heating the blend above the melting point of the highest melting polymer component;
- and (ii) molding the melted blend to have a knit line curved through the thickness of the article resulting from such molding by (a) extruding the body of the melted blend through a die wherein internal surfaces of the die have streamlined irregularities positioned to displace surface material of the melted blend relative to core material of the melted blend and (b) cooling the extruded body to below the melting point of the lowest melting polymer component.
Dependencies are inferred from the claim text.