Synthesis And Spinning Of Meta-aramid Resin

Aramid products as the high-end insulation materials were widely used in power transmission,high voltage generator,and dry-type transformer and traction transformer.At present,China has made a breakthrough in the aramid fiber and aramid paper manufacturing technology,the monopoly of dupont has been broken preliminarily,the imports of product had been replaced partly.But the research and industrialization of the aramid paperboard was still blank.All of the aramid paperboard was imported as the key insulated material of the high speed train traction transformer,which had affected the healthy and sustainable development of the industry.The domestic enterprises were eager to realize the localization of aramid paperboard.In this paper,the synthesis of aramid resin were studied,the effects of raw material ratio,initial reaction temperature,neutralization agent type,water content in the reaction system,reaction adding method and cosolvent on the inherent viscosity of poly m-phenylene isophthalamide(PMIA)were analyzed.The results showed that when molar ratio of isophthaloyl dichloride(IPC)and m-phenylenediamine(MPD)was 1.03,the initial reaction concentration of reaction monomer was 1.0mol/L,the initial reaction temperature was-10℃,water content of the system was 100 ppm,adding times was 2~4 times,the inherent viscosity of PMIA prepared by using organic amine I as neutralizing agent reached the peak value 1.68.The film forming and electrical properties of meta-aramid resin were studied.The results show that in the frequency range of 20Hz-1MHz,the self-made meta-aramid resin film for dielectric loss is between 0.9%-0.18%,the effect of the meta-aramid inherent viscosity on the electrical properties was small,it was conducive to reduce the dielectric loss of the meta-aramid by using organic amine neutralization.The spinnability of meta-aramid resin was studied.The results showed that increasing the molecular weight of the meta-aramid resin,thermal stretching,increasing thermal stretching ratio were conducive to improve the tensile strength of meta-aramid fiber,and the precision of the spinning filter media was beneficial to improve the spinnability of spinning solution.The forming process of the meta-aramid fibrid was studied.The results show that decreasing the resin concentration and flow,increasing the precipitation concentration were conducive to improve the product quality of fibrid;as the shear velocity was slow,the content of long fiber was too much;as the shear velocity was too high,the content of fiber fines was too much,the thermal performance of the fibrid and the mechanical properties of its handsheet was close to the foreign product,and the handsheet’s electrical performance was higher than domestic similar products.An aramid paperboard was prepared from self-made meta-aramid short fiber and fbrid.The effects of the fiber ratio.temperature and pressure on the property of the paperboard were studied.The results show that the optimal fiber ratio between meta-aramid short fiber and fibrid is 5:5,and the optimal process is hot pressing temperature 280 ℃and hot pressing pressure 8MPa.The Long-term heat resistance temperature reached at 224℃.The overall properties of the meta-aramid paperboard had reached the lever of foreign similar product,and it had a good application prospect.