Research On Polytetrafluoroethylene Coating Process And-Performances Of Polyphenylene Sulfide Filter Materials

Polyphenylene sulfide (PPS) fiber has the excellent properties of high temperatureresistance, incombustible, excellent mechanical properties, chemical resistance, etc. It iswidely used in the filtration of high-temperature gas. However, PPS filter material can beeasily oxidative damaged in the use, thus shorten its service life. Response to this case, usingpolyterafluoroethylene (PTFE) for PPS filter coating finish, PTFE can protect the PPS filterbecause of its good chemical stability. But the surface energy of PTFE is low, the adhesivebetween PTFE and the matrix is poor, complete continuous film can’t be formed on the fibersurface of PPS filter, so oxidizing gases, acid drops, high temperature dust can cause bigdamage to the filter and shorten its service life. Therefore, we need to improve the PTFEcoating formulation, so as to improve the film forming and adhesive properties, making thePPS filter material gain better performance after coating finishing.In this study, we add a certain percentage of waterborne epoxy resin and binder in a purePTFE coating agent, complex developed PTFE composite coating agent. Using the PTFEcomposite coating agent for polyphenylene sulfide filter material impregnated coating finish,with single factor and orthogonal experiments to determine the optimum coating bakingprocess, then test and evaluate related performances of coated filter.A certain percentage of binder and epoxy resin were added in the pure PTFE agent toprepare a PTFE composite coating agent. PTFE composite coating agent will form a film afterdrying, test the thickness, mechanical properties, oxidation resistance and adhesionperformance of the film. Comprehensive analysis that optimum formulation of the PTFEcomposite coating, by weight:75parts of PTFE dispersion,20parts of binder,5parts ofwaterborne epoxy resin.By taking single and orthogonal experiment, evaluating the pore diameter to determinethe optimum PTFE coating process on PPS filter material: coating agent concentration is70g/L, baking temperature is200℃, baking time is7min. Under this PTFE coating process,PPS filter material has the minimum pore diameter.Using PTFE composite coating agents, and in accordance with the optimum coatingfinishing process for polyphenylene sulfide filter material’s coating finish. After finishing,evaluate related performance of the material, results are as follows: by scanning electronmicroscopy found a continuous film between the surface of the PPS fibers of the filtermaterial, and the individual fibers are coated with a later of continuous uniform film; theaverage pore diameter of the filter reaches27.67μm, and it is uniform; filtration efficiencytest showed that filtration efficiency reaches34.04%when the filter particle diameter≥0.3μm,filtration efficiency reaches95.02%when the filter particle diameter≥2μm, filtrationefficiency reaches97.86%when the filter particle diameter≥10μm; the oxidation and wearresistance of the PPS filter material has a certain improve; water and oil repellent performancetest showed that PPS filter material has the water repellent for three level and not oil repellent.Summing up all the test results obtained the better PTFE coating process onpolyphenylene sulfide nonwoven filter material: PTFE composite coating agent concentration is70g/L, rolling over rate:70~80%,baking temperature of200℃, baking time is7min,wherein, formulation of PTFE composite coating agent: by weight,75parts of PTFEdispersion,20parts of binder,5parts of waterborne epoxy resin.