Improvements in or relating to the coating of wire, strand, ropes and the like filamentary material with plastic

摘要

A filament (e.g. wire, strand or rope) is coated with plastic by passing it through an aperture of diameter suitable for controlling the thickness of the plastic coating, forming a store or bank of the plastic in a sufficiently fluid condition around the filament at the inlet side of the aperture and drawing the filament through the store and aperture at a speed sufficient to form a rolling doughnut-shaped state of the plastic in the store, and feeding the store with additional plastic to maintain it. Apparatus is described in which a steel wire is pre-heated and passed through a heated die which is supplied with powdered and partly fused polythene from an extruder; alternatively, the pulverulent plastic may be applied to the pre-heated wire by an extrusion process, by dipping in pulverulent plastic, or by a combination fluidised-bed and electrostatic-attraction process, and the roughly coated wire then passed through a heated die. A plurality of dies may be employed, which may be chromium-plated or P.T.F.E. coated and may be of different shapes.ALSO:A filament (e.g. wire, strand or rope) is coated with plastic by passng it through an aperture of diameter suitable for controlling the thickness of the plastic coating, forming a store or bank of the plastic in a sufficiently fluid condition around the filament at the inlet side of the aperture and drawing the filament through the store and aperture at a speed sufficient to form a rolling doughnut-shaped state of the plastic in the store, and feeding the store with additional plastic to maintain it. Apparatus is described in which a steel wire is pre-heated and passed through a heated die which is supplied with powdered and partly fused polyethylene from an extruder; alternatively, the pulverulent plastic may be applied to the pre-heated wire by an extrusion process, by dipping in pulverulent plastic, or by a combination fluidized-bed and electrostatic-attraction process, and the roughly-coated wire then passed through a heated die. A plurality of dies may be employed, which may be chromium-plated or P.T.F.E. coated and may be of different shapes.