Anti-corrosion coating on steel pipe surface is vital for steel pipe service time. Same steel material pipes, some can stay well underground for decades while some start leaking in several years. The main reason about this is that they have different anti-corrosion coating on the surface.
Polyethylene three layer structure protective layers are called 3PE for short. It consists of three main layers: bottom layer (epoxy, 60—80μm thick), middle layer (adhesive, 170—250μm thick), top layer (extruded polyethylene, around 2mm thick). The total thickness of coating is between 2.2mm to 2.9mm. In the three layers, the bottom coating has great anti corrosion performance and cathodic stripping resistance performance, react with the active group of the intermediate layer adhesive to form chemical bond, so that to make sure the three lays adhere with each other well.
The middle layer is copolymer binder. The polar functional groups of the copolymer adhesive can react with epoxy groups of epoxy primer to form hydrogen bonds or chemical bonds, so that the intermediate layer and the bottom layer form good bonding while the non polar ethylene has good affinity with the surface polyethylene, so the inter layer and the surface layer also have good adhesive properties.
The top layer is used for protecting the surface from rusting and mechanical injuries which are also the main function of second layer. Three PE layers take advantage of anti-corrosion and mechanical protection from both epoxy coating and extruded polyethylene. It is excellent material for under-ground pipe protection.
According to related information, 3PE coating can make sure 50 year service life for steel pipes; it is regarded as the most advanced pipe surface anti-corrosion techniques.
Post time: May-22-2018