PBT-3700 series polyethylene tape outer tape (protective tape, protective tape) is made of polyethylene as the base material and butyl rubber as the adhesive layer through co-extrusion and compounding. Because its base film is thick and wrapped around the outer surface of the anti-corrosion tape (inner tape), it mainly plays the role of protecting the internal anti-corrosion layer. It has strong backing material peeling strength and adhesion to prevent it from being damaged during transportation down the ditch. It is suitable for insulation and corrosion protection of various buried pipelines. It has high tensile strength and appropriate elongation at break, which is convenient for mechanized and manual winding.