Study On Preparation And Properties Of Glass Fiber-based Composite Nonwoven Filter Material

Oil filtration can effectively remove the solid impurities and water in the oil,which is of great significance to improve the performance of the oil and reduce the pollution caused by the oil.The glass fiber filter commonly used in oil filtration has the advantages of high filtering precision and large dust holding capacity.However,the glass fiber itself is not resistant to bending,and easy to be damaged in the process of processing and using.In order to prolong its service life,it is usually used after combining with other nonwovens.In this paper,based on the problem that it is difficult to balance the complex fastness and filtration resistance in the glass fiber composite,the spunbonded nonwovens and the glass fiber filter are compounded by thermal calendering after the hot melt adhesive is formed into the ultra-fine fiber mesh by melt-blow.Firstly,the melt-blown process of hot melt adhesive and the influence of the loading of hot melt adhesive fiber on the forming and properties of composite filter material were studied.The copolyester hot melt adhesive was selected by evaluating the adhesion fastness,thermal property and flow property of the hot melt adhesive.The melt point and initial thermal degradation temperature are 125°C and 350℃respectively,and the melt flow index is 30 g/10min.The hot melt adhesive superfine fiber web which is loaded on the spunbonded fabric with an average diameter of 3.5μm can be obtained by the melt spraying process.When the loading is 8 g/m~2,the composite filter material has good shape,reliable combining fastness,and has little obvious influence on the permeability and pore size of the glass fiber filter material.Then the effects of hot calendering gauge,temperature and speed on the forming and properties of the composites were analyzed.The results show that the hot calendering gauge has a significant effect on the shaping and properties of the composite filter material.When the hot calendering gauge is 0.3 mm,the filter material is well formed,and the permeability of the filter material decreases only 10.4%and the average pore size decreases only 1.0μm.The hot calendering speed has a great influence on the bonding effect of the composite filter material.The higher the hot calendering speed,the greater the influence on the bonding effect between glass fiber filter material and spunbonded fabric.Meanwhile,the glass fiber filter material is easy to be damaged when under the high temperature.Hence,choosing the hot calendering speed of 15m/min could ensure the composite effect and the production efficiency and the hot calendering temperature which is close to the melting point of hot melt adhesive could obtain better bonding effect.Based on the heat transfer and the conservation of energy theory,a formula of calculating the theoretical speed of hot calender is established.The hot calendering speed is the most important factor to determine the production efficiency.The establishment of the formula of the hot calender compound theoretical speed can help the producer to set the hot calendering speed reasonably according to the material characteristics and maximize the production efficiency while the hot calendering forming is guaranteed.Finally,the filtration performance of the composite filter material was evaluated.Through the experiments of oil-water separation,oil-solid separation and gasoline resistance of the composite filter material and the original glass fiber filter material,it is found that the composite filter material still has the oil-water separation performance of the original filter material,and the liquid retention ability of the composite filter material is improved due to its hierarchical structure.The results show that the composite filter material has excellent gasoline resistance,and will not degum and crack after exposing in the gasoline environment for a long time.The composite could also delay the formation of filter cake on the surface of the filter,increase the dust capacity of the filter material and improve the pleat resistance of the filter material.This study plays an important guidance role in reducing the filtration resistance and the filtration pressure difference.