Research On High-efficiency Low-resistance Spun-bonded Hot-rolled Filtering Material

This paper is mainly based on the current domestic and foreign research focus about the filtering material, to explore the advantages and disadvantages of deep filtering mechanism and surface filtering mechanism, And according to the specific equipment conditions to design, prepare and evaluate performance of gradient filter material. Combining the actual conditions of the equipments, there were prepared three different gram weight materials that include gradient samples of two kinds of fineness and conventional samples. Text and evaluate the basic performance and the filtering performance of above samples.According to the performance of the several kinds of filtering materials, composite them on basis of gram,realizing the gradient filtering materials with four kinds of fineness combination, test and evaluate filtering performance. Test results show that:(1)When the temperature exceeds 300 degree centigrade, the PET filtering materials in this paper start to break down, the thermal decomposition temperature is at about 380 degree centigrade, Materials decompose fastest in 430 degree centigrade,When the temperature exceeds 600 degree centigrade,the weightlessness rate of materials reached 82%, suitable for filtering under normal temperature environment.(2)Strength aspects: both longitudinal strength and transverse strength,elongation and tear strength of materials, conventional samples are generally greater than the gradient samples, as normally only high gram this situation does not exist.(3)Gas permeability: the gradient filtering material is slightly higher than that of conventional filtering material, and the same material of flower surface(surface with rolling point) permeability is slightly higher than that of smooth surface permeability;For gradient material, the sample of greater gram, the smaller the permeability difference to conventional materials.(4)Spun bonded-hot rolled by two layers of different fineness of fibers and the influence of reinforcement fabric technology, aperture size is not like Needle-punched nonwoven fabric filtering material that has a direct link between fiber thickness. On the contrary,this structure and process make material aperture sizes distribution are relatively concentrated.(5)For the same sample with one side, the size of contact Angle on right and left are around almost no difference, the size of contact Angle of flower surface of gradient sample were greater than that of smooth surface, the sizes of contact Angle of flowers surface and smooth surface of normal sample are not different. And the greater fiber fineness, the larger contact angle.(6)Filtering performance:The residual resistance of filtration material were higher than the initial resistance, the initial resistance and residual resistance of filtering material were higher than that of the gradient filtering material; The same material, when the flower surface is the filtering surface, filtration resistance is lower than when the smooth surface is the filtering surface, the average cycle time is longer than the smooth surface is the filtering surface; But the filtration efficiency is little difference; there are advantages to choose the flower surface as filtering surface; The fineness of the fiber in the flower surface is larger, the fineness of the fiber in the smooth surface is lower, For fineness gradient filter material, The filtering mechanism of deep filter would advantage for structure design.(7)According to the results of performance evaluation of eight samples, choose these samples and superpose and combine into five groups of new samples on the basis of gram control.Text and evaluate the filtering performance of them. The results showed that: Not all the filtering performance of the gradient filter material of is superior to the conventional filter material, Experimental results in this paper a set of conventional filter material of filtering performance is better than the other three groups gradient filter material, But its filtration resistance is close to another group of gradient filtering material, and its filtration efficiency is slightly lower than the group;On the other hand, calculate the average of fiber fineness of gradient sample,equivalent to turn it into a flat structure with this fineness of the general samples;Calculate the filter performance based on related parameters and the filtration theory model, Comparing the theoretical calculation results and actual test results, found that there was a same trend about filtration efficiency. Indicates that this theoretical model is useful to design the structure of gradient filtering materials. And for the gradient filter material, microscope images of filtering surface show that: the dusts distribute in the material as the form of group or a block tangles,it can confirm that the mechanism of dust filter dust in deep filtration theory,Instead of the other surface, the fibers are clearly visible, there are almost no large dust and form a bright contrast.High-efficiency low-resistance filtering material is a hot research topic at home and abroad in recent years, But so far there are no sure of filtering mechanism, and environmental problems must to be solved, in this paper, the gradient filter material still have some shortcomings, also faces many problems in the practical use, more research is needed.