The 3PE anti-corrosion pipeline production line and technology were successfully developed by Qingdao Huashida Machinery Co., Ltd., based on the introduction of advanced anti-corrosion technology from abroad. In the three-layer structure, the epoxy primer is a thermosetting, non-toxic coating that, once cured, forms a high molecular weight cross-linked structure. It exhibits excellent chemical corrosion resistance and high mechanical properties, particularly in terms of wear resistance and adhesion. The epoxy primer can form a continuous coating that directly bonds with the steel pipe surface, providing excellent resistance to chemical corrosion and cathodic disbondment. It reacts with the active groups of the intermediate layer adhesive to form a chemical bond, ensuring the overall anti-corrosion layer maintains good adhesion at higher temperatures, making it an ideal anti-corrosion coating for buried steel pipelines.

The intermediate layer is typically a copolymer adhesive, with the main component being polyolefin, and the widely used adhesive is a vinyl copolymer. The polar functional groups in the copolymer adhesive can react with the epoxy groups of the epoxy primer to form hydrogen or chemical bonds, allowing for strong adhesion between the intermediate and base layers. The non-polar ethylene part of the adhesive also has good compatibility with the outer polyethylene layer, ensuring strong adhesion between the intermediate and outer layers. The three-layer polyethylene anti-corrosion structure, used as the external protection layer for buried pipelines, is highly superior and has been widely applied in domestic projects such as the West-East Gas Transmission and oil pipeline transportation, as well as urban gas and water supply pipeline anti-corrosion.

Through research and development by Huashida's technical team, the 3PE anti-corrosion pipeline production line and technology allow for the efficient application of three-layer PE, powder coating, and tape anti-corrosion through a spiral conveyor system. By adjusting the angle of the production line's conveyor rollers, various anti-corrosion operations can be completed. When foam jacket anti-corrosion insulation is required for steel pipes, adjusting the conveyor rollers to be parallel to the production line allows the steel pipe to move straight, completing the foam jacket anti-corrosion and insulation process. For foam jacket anti-corrosion insulation, the three-layer PE extruder can be used, with the "T" shaped (sheet) die head replaced by an "O" shaped (cylindrical) die head to produce a one-step foam jacket insulation pipe.

Some specialized equipment for the three-layer PE and foam jacket process, such as die heads and skew correction machines, can be easily interchanged for flexibility. The 3PE anti-corrosion pipeline production line and technology can be manufactured as a skid-mounted structure for easy onsite construction and transport. By adding equipment such as tape wrapping machines, powder coating machines, and adhesive applicators, the production line can complete operations like tape wrapping, epoxy powder coating, and epoxy coal tar pitch wrapping to meet the needs of different customers in various steel pipe anti-corrosion and insulation projects.

Due to the use of electromagnetic heating technology, the production line saves about 50% of electricity compared to traditional equipment. Additionally, its multi-functional capabilities reduce customers' line construction costs.