Study On The Performance Of Double-Layer Automotive Curing Filter Paper

In recent years,as environmental pollution has aggravated,the increasing performance demands emerged.At present,most of the filter paper in market is single-layer,but the internal structure of single-layer filter paper is too single to adjust the contradiction between filtration resistance and filtration efficiency.To find a balance between filtration efficiency,filtration resistance and dust holding capacity,many manufacturers have focused on composite filter paper.The internal gradient structure of composite filter paper was a main research structure.That is,the gradient distribution of the pore diameter in the section direction could be realized in the interior by effectively controlling the process conditions,so as to achieve the effect of layer-by-layer filtration.In this paper,the effects of total ration,ration ratio,ratio of inflow layer and outflow layer slurry on the properties of double-layer composite air filter base paper were studied.The influences of resin impregnation,curing time and curing temperature on the properties of composite filter paper were investigated,following by comparision of experimental sample and commercial sample.In this paper,different methods for preparing double-layer composite air filter paper were explored.By studying the properties and cross-sectional structure,it found that the prepared composite filter paper was endowed with high air permeability,filtration efficiency and dust capacity,unobvious interlayer interface,and fine filtering effect.Double-layer composite air filter papers with different total rations and ration ratios were prepared to study the effects of ration changes on properties of double-layer composite air filter paper.The results showed that with the increase of total ration,the pore size,the air permeability and dust capacity all decreased,while the filtration efficiency increased.When the total ration was 120 g/m2,the filtration efficiency and the dust capacity were 99.68%and 117 g/m2,respectively.With the increasing ration ratio,the dust capacity increased firstly and then decreased,and the filtration efficiencies were basically constant.Combined with the internal structure diagram,it can be seen that the best value obtained at ration ratio of 1:3.By comparing with single-layer filter paper,the filtration efficiency of composite filter paper was higher than that of single layer filter paper,with the maximum difference of 0.1%.The effects of the ratio of inflow layer to outflow layer slurry on the properties of double-layer composite air filter paper were investigated.With changing the ratio of inflow layer slurry by changing the relative content of hardwood pulp,the air permeability,pore size and initial resistance reduced;tensile index increased;filtration efficiency increased firstly and then decreased;dust capacity decreased.With changing the proportion of the outflow slurry by changing the relative content of softwood pulp,the tensile index,air permeability,pore size,and dust capacity all increased,while the filtration efficiency reduced.According to orthogonal experiments,the main factors affecting the filtration efficiency and dust capacity were the proportions of the outflow layer slurry and inflow layer slurry,respectively.The optimal slurry ratio for optimizing filtration performance of double-layer composite air filter paper were as follows:1:1:0 of the inflow layer slurry ratio,and 0.1:1:1 of he outflow layer slurry ratio.The filtration efficiency was 99.88%and the dust capacity was 163 g/m2.By FTIR,DSC and TGA analysis of phenolic resin,ether bond and methylene group would be formed during curing process of phenolic resin.When curing temperature is too high,carbonyl group was formed,which would affect the carbonation rate of composite filter paper.In addition,the effects of resin impregnation,curing time and curing temperature on the properties of composite filter paper were studied by the response surface experiment.The results showed that the best curing conditions were 24.14%of resin impregnation,8.07 min of curing time and 164.78? of curing temperature.Under these curing conditions,the actual cured paper had a stiffness of 123 mN and a bursting resistance of 220.23 kPa.The degree of curing at different curing times and different curing temperatures was analyzed by curing degree and Cobb value.It was found that the longer the curing time,the higher the curing degree,the stronger the water resistance,the smaller the Cobb value;the higher the curing temperature,the higher the curing degree,the smaller the Cobb value.When curing temperature was 180?,the paper became brittle and hydrophobic,and the Cobb value increased.Compared with commercial sample,the tensile index and bursting strength were lower than the commercial sample,and the stiffness,air permeability,pore diameter,filtration efficiency and dust capacity were higher than the commercial sample.The self-made sample had a tensile index of 26.01 N·m/g,bursting resistance of 220.23 kPa,stiffness of 117 mN,gas permeability of 297 L/m2·s,maximum pore diameter of 29.2 ?m,and pore diameter of 13.8?m.The filtration efficiency was 99.91%,and the dust capacity was 155 g/m2.