process to play a lead

摘要

Steel pipe is provided with protective coating by first applying a corrosion protective coating such as fused powdered epoxy resin or heat activated adhesive or butyl-based pressure-sensitive adhesive adhered to the pipe, then extruding or coextruding an outer polyolefin layer directly onto the corrosion protective coating. The coextrusion step may include an outer layer of high density polyethylene and an inner adherent layer of low density polyethylene, or an outer layer of polyethylene or polypropylene and an inner layer of a copolymer of ethylene or propylene and acrylic acid.