Abstract: A double-layer medical catheter with an integral soft tip is made by the coextrusion of a relatively rigid inner layer and a relatively soft outer layer, where the extrusion equipment is configured and so controlled to interrupt the supply of the material for the inner layer to form a periodic void in the inner wall. The act of interrupting the supply causes a ramp down in the inner wall thickness at the leading edge of each void and the ramp up of the thickness at the trailing edge. The void is cut to produce two ideal integral soft-tipped catheters.

Abstract: Plastic replacements for glass capillary tubes for drawing samples of blood or other body fluids are achieved by texturing the inside surface of the tube with uniform fine features and by extruding the tube over a suitably textured tapered pin with a (gradual) ratio of at least 6:1 during extrusion to ensure the transfer of the pin's surface texture to the inside diameter of the tube.

Abstract: A splittable tube, useful in medical applications as a cannula for insertion into the body, comprises an inner and an outer layer. The inner layer defines a central lumen for accepting catheters and probes. The inner layer also includes a longitudinal slot through its wall for defining a stress line in the outer layer. The outer layer is very thin, membrane-like, and tears along the longitudinal stress line when the cannula is pulled to the side of a catheter occupying the central lumen. The tube may be made of electrically insulating material and used, for example, as strippable insulation as telephone or house wire, and strippable without the use of tools.

Abstract: A collapse-resistant catheter adapted for medical usage includes a central tube having a smooth outer wall rather than a corrugated outer wall characteristic of prior art collapse-resistant catheters. The tube includes an integral, spiral-shaped outer tube which provides the collapse-resistant characteristic. The spiral tube also provides an additional lumen. The center tube is adapted to provide for a multilumen structure not possible with corrugated prior art structures. The resulting structure, single or multilumen, can be made sufficiently small for insertion into the human body.

Abstract: A layer of conductive plastic material can be made to exhibit relatively high conductivity with a relatively small amount of electrically conducting particles included in it if the layer is extruded in a lamellate form. Particularly, sublayers having thicknesses of the size of the conducting particles or less being the randomly distributed particles in one sublayer into close proximity with those in adjacent sublayers. Consequently, relatively short conducting paths through the layer are provided. The laminate layer is formed by an extrusion die with a plurality of dividers adapted to divide the extrudate into sublayer prior to recombination for the extrusion of the final layer. The laminate layer can be coextruded with electrically insulating layers to fabricate electrical components such as capacitors.

Abstract: Medical catheters with splined internal walls are disclosed as having sufficient rigidity to transmit torque from the proximal end to the distal end even over the long distances required for angioplast procedures. The splined geometry obviates the need for mesh layers characteristic of prior art guiding or diagnostic catheters and thus are significantly narrower and less costly to produce.