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.

Polytetrafluoroethylene coatings are widely used in various industries due to their high chemical stability, wide temperature range, outstanding non-stickiness, good thermal stability, excellent aging resistance and radiation resistance. 2. However, the poor wear resistance of PTFE anti-stick coatings limits its application range to a certain extent.1 Coating formula (see Table 1) .

Test materials and main equipment 1.2 Main equipment Power-increasing electric agitator; 202-1 type electric ptfe coated fiberglass adhesive tape heating constant temperature drying oven; 4-10 type box-type resistance furnace; SS16 type liquid sandblasting machine; W-71 type spray gun. 1.1 Test materials Polytetrafluoroethylene concentrated dispersion SFN-1, Sichuan Chenguang; Tin bronze powder QSn6-6-3, Qishan, Shaanxi; Molybdenum disulfide (analytical grade), Shanghai Chemical Reagent Factory; Chromium trioxide (analytical grade),

Tianjin Chemical Reagent factory; polyphenylene sulfide resin, Zigong, Sichuan; titanate coupling agent NDZ-311, NDZ-311W, Nanjing Shuguang; Foamaster111 defoamer, Levelling620 associative leveling agent, film-forming aid alcohol ester 12 , Henkel, Germany; 7010 defoamer, Jieyang Tianyin; Triethylamine (analytical pure), Tianjin. 

Preparation of modified polytetrafluoroethylene coating Choose polytetrafluoroethylene concentrated dispersion as the base material, add fillers (the fillers are dried through a 600-mesh screen) and additives, the steps are as follows: (1) Weigh the required concentrated PTFE dispersion and stir at high speed; (2) Add the required amount of tin bronze powder, molybdenum dioxide, chromium trioxide, polyphenylene sulfide resin, and stir at high speed.

 Coating preparation and coating performance In this study, polytetrafluoroethylene suspension was used as the main component of the coating, and inorganic coatings such as chromium trioxide, bronze powder, molybdenum disulfide, organic filler polyphenylene sulfide resin and additives were added. The modified polytetrafluoroethylene coating developed in this experiment has excellent wear resistance and can effectively expand the application field of coatings.

It can also be applied to glass, glass fiber And some non-metallic materials such as rubber. In fact, spray coating exhibits self-cleaning properties in many cases. Generally, Teflon spraying is not affected by the chemical environment. Teflon? Industrial coatings can be used at temperatures as low as 270oC/-454oF.kytfl. Very few solid substances can permanently stick to the spray. After special formula or industrial treatment, it can even have certain conductivity and can be used as antistatic coating. In a fairly wide frequency range, Teflon has high dielectric strength, low dielectric coefficient, and extremely high surface resistance.

Although the gelatinous substance may adhere to its surface to some extent, most materials are easy to clean on its surface. Many Teflon industrial coatings can withstand the harsh absolute zero without loss of mechanical properties.05~0. Teflon, Teflon spraying can be applied to carbon steel, stainless steel, aluminum, copper, magnesium and various alloys and other metal materials. 2.html Teflon coating, Teflon coating.

The only chemicals known to affect Teflon are molten alkali metals and fluorinating agents at high temperatures. Spraying has strong high temperature resistance and fire resistance.Teflon spraying TEFLON is also called Teflon spraying. The application of Teflon spraying is usually a combination of its own superior performance, and its performance includes: Teflon sprayed surface has strong hydrophobicity and oleophobicity, so it is easier to clean thoroughly.

This is because Teflon has a high melting point and spontaneous ignition point, as well as unexpectedly low thermal conductivity. The maximum working PTFE coated tape Factory temperature of Teflon spraying can reach 290°C, and the intermittent working temperature can even reach 315°C. Teflon sprayed surface has very low surface tension, so it shows strong non-stickiness.depending on the surface pressure, sliding speed and spray application. Teflon spraying has the lowest coefficient of friction among all solid materials.