Process for coating webs with polyethylene
AssigneeDu Pont Canada Inc.
InventorGeorge White
Life of this patent
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Abstract
A process is provided for coating of substrate webs with polyethylene wherein the edge thickening and other processing difficulties caused by the necking-in phenomenon are minimized. The process comprises extruding a polyethylene having a melt index between 30 dg/min and 100 dg/min through a slot in a slotted die in the form of a sheet onto the moving substrate web to form the coated web, and passing the coated web through a nip roll assembly comprising a chill roll and a nip roll, the slotted die having at the extremities of the slot therein edge guides which are maintained at a temperature above the melting temperature of the polyethylene and are contoured to guide the adhered edges of the extruded sheet into the throat of the nip roll assembly.
Claims10
A process for coating a substrate web with a polyethylene in which process the polyethylene, having a melt index of between about 30 dg/min and about 100 dg/min, is extruded through a slot in a slotted die in the form of a sheet having two edges onto the substrate web being transported past the slotted die, to form a coated web;
- and subsequently the coated web is passed through a nip roll assembly comprising a chill roll and a nip roll which form a throat therebetween, said slot at the extremities thereof having edge guides which are maintained at a temperature higher than the melting temperature of the polyethylene and are adapted to guide the two adhered edges of the extruded sheet into the throat of the nip roll assembly.
Dependencies are inferred from the claim text.