Abstract: A machine for applying one or more protective layers of material onto a tubular member, for example a pipe, in a substantially wrinkle free and continuous manner. The machine includes a brake tension unit for applying a constant tension to the protective material in order to neck down the material as it is applied onto the pipe, and a base unit for supporting and rotating the pipe. The constant brake tension unit preferably includes a conventional disc brake and a mounting arm for holding a core of material in engagement with the brake tension unit. Pressure applied to the rotor slows rotation of the rotor and the attached core which restricts the unwinding of the protective material from the core. Thus, as the material attempts to unwind from the core a preselected force is applied to resist the unwinding. The material is therefore placed under tension and, due to the nature of the protective material, the material elongates and necks down under the applied pressure.

Abstract: A primer for protecting the exterior surfaces of an underground metal pipe against corrosion at temperatures of up to 250.degree. F. includes a butyl elastomer, an aliphatic hydrocarbon resin, a heat curable phenolic resin which crosslinks at between approximately 180.degree. F. and 250.degree. F., and a hydrocarbon solvent. The primer can be effectively utilized in a method which includes the steps of applying the primer to the exterior surface of a metal pipe, allowing the primer to at least partially cure, and applying a protective adhesive tape to the pipe over the primer.

Abstract: A method and apparatus for forming intimately fused, multiple layer co-extruded adhesive tapes. The apparatus includes a co-extrusion die having an outlet aperture therein of elongated width and reduced height and first, second and third interior extrusion channels which merge in the interior of the die to form a common outlet channel which passes outwardly through the outlet aperture. The apparatus is operative in accordance with the method by feeding a first pressurized stream comprising a molten elastomeric based adhesive polymer to the first extrusion channel, a second pressurized stream comprising a molten flexible thermoplastic polymer and an elastomerically compatible coupling agent to the second extrusion channel and a third pressurized stream comprising either a molten flexible thermoplastic polymer or a molten elastomeric based adhesive polymer to the third extrusion channel.