Performance Research And Critical Technologies Of Hydroentanglement High Temperature Resistant Filtration Material

As people's requirements for the quality of the living environment increasing, the application of the filter material is more and more extensive. For the high temperature resistance filtration material used in the industry field, not only the dosage is increased, but also the filtration performance need enhanced. Our domestic products is hard to meet the status quo, both in yield and quality. Most of the products are still depend on imports, result in the great cost of China's environmental protection industry.We used the new spunlace process that replaced the needle punched process to reinforce the composite fiber network, in order to improve the performance of high-temperature filter material, reduce energy consumption and cut raw material consumption. We chose the PPS, Nomex, and P84 fiber commonly used in market as raw material, used the dual-cylinder double doffer carding mechanism to get thin fiber network and put the fiber gridding cloth between the up and down webs, then pre-needled the composite-fiber network before hydro entanglement. Analyses of the water jet phenomenon and calculated the water energy, we found that the entanglement taken place not only between fibers, but also between the fiber and the fiber gridding cloth. In order to entangle the fiber fully and to avoid stratification of the production, we needed to increase the water pressure. But when we increased water pressure, the water would remain on the surface of the fiber web, and this resulted wrinkle on the web's surface, seriously affected the quality of product. To avoid this situation, experiments and exploration found when we raised the water pressure, we mast raise the pressure of the vacuum suction too. We set and adjusted process parameters to get the final test samples. We obtained theory and efficiency of different filtration methods by analyzing the internal porosity characteristics of the materials. To tested the material's basic performances without finishing process, we found that in normal circumstances, along with the decrease of the speed of conveyor belt, with the increase of the water pressure and the spunlace times, the strength of the material increased first and then decreased, elongation remained unchanged, permeability reduced, the filtration efficiency of the tiny dust particles increased, and the thickness gradually reduced. When the process conditions are not ideal, along with the water pressure and the spun-laced times increased, the thickness increased, in the cross direction the strength reduced and the elongation increased. When the spunlace times and the water pressure are too large, fiber will unwrap, the larger pores will appear, and the filtration efficiency will reduce.The hydroentanglement high temperature resistant filtration material has certain advantages, but the process is still in immature stage, further research needs to be done to ensure the validity of spunlace process.