1.Because of the high crosslink density of the benzene ring and solidified coating in the epoxy resin, make the coating has higher hardness, smaller coefficient, and worse flexibility than polythylene. If the production process is not controlled well, a small amount of epoxy resin coating will crack, and the 3LPE Coated Steel Pipe will crack less because of its toughness.
2.Because the epoxy group in epoxy resin reacts with the free bond on the inner surface of the Inner EP Coated Steel Pipe, to form a solid chemical bond, and produces a strong adhesive force. The adhesion of epoxy resin is greater than polyethylene.
3.If the coating of epoxy resin is not firmly welded with the steel tube, there is an air hole in the weld seam of the epoxy resin coating, which may produce bubbles on the surface of the coating, while polyethylene is seldom produced.