Plastic coated composite steel pipe
Epoxy resin anticorrosion inside and outside the elbow
Production and processing range of internal and external epoxy coated elbows φDN80—ΦDN1800
The inner and outer epoxy resin-coated elbows are commonly used in fire water supply. In the building fire protection system, the internal and external coated epoxy elbows play an important role, so the internal and external coated epoxy elbows have better quality. The internal and external coated epoxy resin samples (4 photos) are the key to mastering the fire protection system. , So let's introduce the production process of the inner and outer epoxy resin elbow, the performance of its powder (epoxy resin), and the product performance of the inner and outer epoxy elbow.
The inner and outer coated epoxy resin elbows are first pretreated to the base pipe-the elbow is polished (Advantages: automatic spraying makes the inner and outer walls of the base material evenly coated and has good leveling. It reaches the CJ/T120-2016 standard and GB/T5135.20---2010 Standard---Put the polished elbow pipe into an electric oven for preheating, when the temperature reaches 230°~250° (generally preheating for about one and a half hours)) ---- Yes The preheated pipe is painted-after the painting is finished, put it in the curing box for curing (when the temperature reaches 200 degrees, keep it for 15 minutes)-finished product. After spraying, the heating equipment is preheated to 180 degrees to cure the sprayed substrate. Advantages: The epoxy resin powder is not completely fused to the inner and outer walls of the substrate during spraying. After 30 minutes of preheating and curing, the epoxy The curing agent in the resin is completely cured, making the coating adhesion on the inner and outer walls stronger.
The earliest internal and external epoxy resin coated elbow base pipes in our country are all galvanized elbows. Later, it was found that the inner galvanized layer was not good for improving the adhesion of the internal coating, but it had an impact. To improve the adhesion of the inner coating, the zinc removal process must be adopted for the inner galvanizing of the galvanized elbow, which once again increases the cost and also causes a waste of energy. Therefore, some welding elbows are directly coated. The inner and outer epoxy resin elbow pipe base pipe should be sandblasted before plastic coating to remove the rust, oil stain and galvanized layer on the metal surface, which is generally called surface pretreatment. The construction industry has no quantitative index requirements for surface pretreatment, and the petroleum industry is relatively specific
1. High mechanical properties. Epoxy resin has strong cohesion and compact molecular structure, so its mechanical properties are higher than general thermosetting resins such as phenolic resin and unsaturated polyester.
2. Strong adhesion. The epoxy resin curing system contains extremely reactive epoxy groups, hydroxyl groups, ether bonds, amine bonds, ester bonds and other polar groups, which endow the epoxy cured products with extreme resistance to metals, ceramics, glass, concrete, wood, etc. Sexual substrate with excellent adhesion.
3. Small curing shrinkage. Generally, it is 1%~2%. It is one of the varieties with the smallest curing shrinkage rate among thermosetting resins (phenolic resin is 8%~10%; unsaturated polyester resin is 4%~6%; silicone resin is 4%~8%). The coefficient of linear expansion is also very small, generally 6×10-5/℃. Therefore, the volume changes little after curing.
4. Good craftsmanship. The epoxy resin basically does not produce low molecular volatiles when it is cured, so it can be molded at low pressure or contact pressure. It can be combined with various curing agents to produce environmentally friendly coatings such as solvent-free, high-solid, powder coatings and water-based coatings.
5. Excellent electrical insulation. Epoxy resin is one of the best dielectric properties among thermosetting resins.
6. Good stability and excellent chemical resistance.
7. The heat resistance of cured epoxy is generally 80~100℃. The heat-resistant varieties of epoxy resin can reach 200℃ or higher.
The inner and outer coated epoxy resin elbows are thermosetting plastics because of the heavy-duty anti-corrosion modified epoxy resin. The coating has good temperature resistance and can be used for a long time at -30℃~200℃ without burning. At the same time, it has chemical corrosion resistance, extinguishing agent corrosion resistance, high temperature resistance and wood pile fire resistance, as well as anti-corrosion or flame resistance under water and no water conditions. It is especially suitable for fire fighting water and gas fire fighting. The internal and external coated epoxy elbows have excellent chemical resistance, water resistance, solvent resistance, protein, and high-expansion foam extinguishing agent corrosion, which solves the problem of water transport, burying, acid, alkali, and salt to metal pipes. Corros
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