The fourth is that it is difficult to form the cavity lining of the equipment with complex structure. Chemical equipment, such as reactors, polymerizers, towers, storage tanks, storage tanks, various pump valves, tower sections, heads, metal composite plates, agitators, straight pipes and other chemical equipment in the fields of chemical industry, petroleum, medicine, pesticide, metallurgy, etc. Inner lining Deformation and delamination.

However, to enhance polyethylene (PE), polypropylene (PP), polyolefin (PO), polyfluoroethylene ; hexafluoropropylene copolymer (F46), soluble polytetrafluoroethylene (PFA), polychlorotrifluoroethylene (F3), Polyvinylidene fluoride (F2) is an anticorrosive lining for chemical equipment, and its application has limitations: First, the use temperature is low , which will easily cause the lining material to soften and melt, resulting in sealing Leakage.

However, PTFE material has a large thermal expansion coefficient (7710-6~10010-6°C) and is a metal material (stainless steel 16.The application limitations of polytetrafluoroethylene (PTFE) lining technology: my country's petroleum, chemical, pharmaceutical, pesticide, dye and other industries cause economic losses of about 400 billion yuan each year due to equipment corrosion, and loss of steel about 15 million tons. Second, when the lining flanging is finalized, due to the stress difference, flanging fracture is easy to occur, causing leakage and corrosion. The third is the impact and abrasion of the liquid medium, resulting in seal leakage.

Moreover, the cold flow (creep) of PTFE and the defects of the above-mentioned PTFE lining molding technology cannot completely make the PTFE lining and the metal shell of chemical equipment closely fit, so its practical application also has limitations : First, PTFE Fiberglass Fabric the temperature change during the use of chemical equipment due to heating and cooling causes the lining and the metal shell to expand and contract inconsistently.

Especially under negative pressure operation conditions, the PTFE lining is easy to deform, drum, collapse, wrinkle, delamination, Defects such as flattening and deflation. Accessories. Its anti-corrosion performance exceeds other non-metallic materials, and is superior to high-grade alloys such as stainless steel, alloys and even lead.

Although polytetrafluoroethylene is the chemically stable material, it has a wide temperature resistance range, long-term use temperature -250~260℃, good corrosion resistance, acid, alkali, salt, strong oxidant, strong reducing agent, organic solvent and others Corrosion of strong corrosive media (except molten alkali metals and elemental fluorine) is an ideal material for chemical anti-corrosion equipment linings. The second is that the lining is easily corroded and damaged in the severely corrosive acid, alkali and other media.