Research On The Ptfe Emulsion Finishing Of Polyester Needle Punched Nonwoven Filter Material

In recent years, with the increasing pollution by the industrial waste water and gas, people pay attention to filter material gradually. Filter materials are widely used in environmental protection, automotive industry, and medical field. Because of their excellent filtration performance, high production with lower cost, the nonwoven filter materials have gradually replaced the traditional knitted and woven filter materials. At the same time, their usages have been greatly increased year by year.Polyester needle punched nonwoven filter materials have flat surfaces, high strengthes and high economic benefits. On the other hand, they have large pore size and highly porous. Therefore, the polyester needle punched nonwoven filter materials can’t trap the particulate matter in the waste gas, so the desired filter effects are difficult to attain. The PTFE emulsion has good physical and chemical properties. Finishing with the PTFE emulsion can improve the filter materials’heat resistance, cold resistance, abrasion resistance, chemical corrosion resistance, with the resistance to water and oil.Based on the previous research of the nonwoven filter materials’surface property, flow property and film property, in the paper, the effect of eight different process parameters on properties of three kinds of filter materials are studied. These properties are ventilation property, weight gain rate, resistance to water and oil. These different parameters are impregnation temperature, soaking time, pressure, the concentration of PTFE emulsion, pre-drying temperature, pre-drying time, baking temperature and baking time. And these filter materials are not completely the same. Finally, synthesizing the ventilation property, the weight gain rate, the water-repellent and the oil-repellent, together with the appropriate factors and levers, the finishing processes for two kinds of polyester needle nonwoven filter materials were optimized by orthogonal experiments. Then each process parameters’effect on the ventilation property, the weight gain rate, the water-repellent and the oil-repellent of the PTFE emulsion are obtained.The results show that the effect of the eight parameters is not the same for the filter materials because of the materials’different structures. By orthogonal tests and intuitive analysis, the optimum processes, which can give the optimum ventilation property, water-repellent and oil-repellent for filter materials with different structures, are concluded respectively. After testing, better ventilation property, water-repellent and oil-repellent can be attained by the optimum finishing processes.The optimum finishing processes for the ventilation property and the water-repellent of filter material with loose construction are as follows:the soaking time is15min, the pressure is0.2MPa, the pre-drying temperature is100℃, the pre-drying time is5min, the baking temperature is180℃, and the baking time is7min. And the soaking time is10min, the pressure is0.4MPa, the pre-drying temperature is100℃, the pre-drying time is15min, the baking temperature is180℃, and the baking time is3min.The optimum finishing processes for the ventilation property, the water-repellent, and oil-repellent of filter material with dense construction are as follows:the soaking time is15min, the pressure is0.5MPa, the pre-drying temperature is80℃,the pre-drying time is10min, the baking temperature is160℃, and the baking time is3min. And the soaking time is15min, the pressure is0.4MPa, the pre-drying temperature is90℃, the pre-drying time is10min, the baking temperature is180℃, and the baking time is7min. And the soaking time is5min, the pressure is0.5MPa, the pre-drying temperature is90℃, the pre-drying time is10min, the baking temperature is180℃, and the baking time is7min.The paper studies the optimum processes with different structures, which can be applied in different industries. And the process can be selected for a special application.