Research On The Manufacturing Of Dryjet-wet Spinning Pan Fiber By The Speed Of 300m/min

As a major enhancement phase of high performance composites,carbon fiber is a national strategic material.The precursor directly affects the quality of the carbon fiber.In order to improve the quality of carbon fiber,the first thing is to improve the quality of precursor.At the same time,production increasement and cost reduction are also significant in China’s carbon fiber industry.The production of carbon fiber relies on the output of precursor,and the precursor production is mainly determined by the spinning speed.Based on this,this paper focuses on how to improve the quality and production of polyacrylonitrile(PAN)based carbon fiber precursor and the dry-jet wet spinning process with speed of 300 m/min.Compared with wet spinning process in which the spinning solution thread directly enters the coagulation bath,dry-jet wet spinning improves both the spinning speed and the production efficiency,which is also an effective way to reduce costs.As a new type of spinning method developed in recent years,the mechanism of mass transfer and heat transfer of dry-jet wet spinning is not very clear.At present,the research is mainly based on experiments.The purpose of this research is to study several important processes which determine the quality of dry-jet wet spinning in order to achieve high quality,high speed dry-jet wet spinning.Firstly,the study of polymerization(spinning solution),the ways of mixing spinning solution are studied and chosen-impeller mixing,which makes the stirring more evenly.Then the temperature control mode of polymerization reaction kettle is determined-using the built-in coil and jacket temperature control mode,which ensures the quality of the polymerization reaction.Based on the spinnability of spinning solution and the relationship between the strength of carbon fiber and spinning solution,appropriate molecular weight and solid contents.Secondly,the study of spinning process: The key process parameters which determine the quality of spinning are studied.Based on the effects of spinning solution thread and effective action of fiber formation,the finish of spinneret and solidification temperature/ concentration are determined.The leading precursor speed,tensile ratio and coagulation time are also determined through plenty of trials.Washing effect is achieved by the temperature control of water and the introduction of ultrasonic washing.Finally,the study of post-process after precursor formulation: The dryness of precursor is attained by gradually increasing temperature,which can prevent precursor monofilament,eliminate the skin-core structure and realize drying densification of the precursor structure.The design goal of high speed is achieved by twice precursor tension in five-time tensile ratio.The research results of this paper have implemented on the one thousand tons of production line,the design goal of 300 m/min spinning speed and the steady production has been achieved.After carbonization the performance of the carbon fiber original wire reached the T700 S indicators,the research object has been achieved.