3PE anti-corrosion pipe is used in different working environments. In order to slow or prevent the erosion and deterioration of the pipe under the chemical and electrochemical action of the external medium or due to the metabolic activity of microorganisms, 2 or 3 layers of polyethylene (3PE) are coated on the external wall to achieve the anti-corrosion of the pipe, and the service life of 3PE anti-corrosion pipe is extended by 3-5 times. Polyethylene three-layer structure protection layer, also known as three-layer PE (3PE), is an advanced anti-corrosion technology introduced from abroad in recent years. Its full name is fused epoxy/extruded polyethylene structure protective layer, the structure is composed of the following three layers: the bottom layer is fused epoxy (≥80 m); The middle layer is adhesive (170 -- 250 m). The surface layer is extruded polyethylene (about 2mm). The total thickness of the protective layer is about 1.8-3.7mm. In the three-layer structure, the main function of fused epoxy powder coating is to form a continuous coating film and bond directly to the surface of the steel tube, which has good chemical resistance and anti-cathode peel performance. It reacts with the active groups of the intermediate layer adhesive to form a chemical bond, which ensures that the whole anticorrosive layer has a good bond at a high temperature. The intermediate layer is usually copolymer binder, whose main composition is polyolefin, and the vinyl copolymer adhesive is widely used at present. The polar functional groups of the copolymer adhesive can react with the epoxy groups fused to the epoxy powder coating to form hydrogen bond or chemical bond, which makes the middle layer and the bottom layer form a good bond. But the non-polar ethylene part and the surface layer polyethylene have very good cooperation, so the middle layer and the surface layer also have very good bond performance. The main function of polyethylene surface layer is mechanical protection and anticorrosion, which has the same function as the traditional two-layer structure polyethylene.
3PE anti-corrosion steel pipe production standard: domestic SY/T0413-2002 standard, implemented on August 1, 2002. The main specifications are polyethylene and high-density polyethylene, and the softening point of vica shall be no less than 110℃. The thickness of the outer anticorrosive coating is determined according to the German standard DIN30670-1991, which is based on low and medium density polyethylene. The impact strength of 3PE anticorrosive coating is greatly improved. SY/T0413-2002 greatly improved the stripping strength and impact resistance of 3PE anticorrosive coating, and clearly stipulated the carbon black content of some special materials, which ensured the mechanical strength and weather resistance of 3PE anticorrosive coating, and increased the sampling frequency of the patch stripping strength (namely the stripping strength of heat-shrinkable sleeve and heat-shrinkable band to primer steel).
The safety of pipeline is a very important issue, and people pay more and more attention to it. Due to the corrosion and manufacturing defects of the steel pipe, as well as the third party, natural crowding, man-made damage and other reasons, pipeline accidents occur frequently, seriously affecting the normal operation of the pipeline, people's lives and property and the surrounding natural environment, the safety and reliability of the pipeline is becoming increasingly prominent. With the construction and operation of some high-risk value pipelines, the importance and urgency of oil and gas pipeline safety become more prominent. Buried anticorrosive tape refers to the adhesive tape used for anticorrosion of buried steel pipelines in petroleum, natural gas, chemical industry, urban construction, water supply and drainage, gas transmission, etc., which plays an effective role in protecting buried pipelines. The implementation standard is SY/T 0414-98 or SY/T 0414-2007, among which SY/T 0414-2007 is a new standard just issued in 2008. At present, the adhesive tape products used for the anti-corrosion of the floor pipe mainly include polyethylene anti-corrosion tape, polypropylene fiber anti-corrosion tape, POLYETHYLENE 660 type anti-corrosion tape, epoxy coal asphalt anti-corrosion cold wrapping tape, among which the application range of polyethylene anti-corrosion tape and polypropylene fiber anti-corrosion tape can fully meet the requirements of various anti-corrosion projects of the pipeline.
