The Investigation Of Nonwoven Uniformity Performance With The Application Of Static Electricity To Spunbond Process

Spunbond process is a cost-efficient method.The uniformity of spunbond influence its appearance,hand feeling and mechanical properties.There are various of methods which can improve its uniformity,such as improving drafting system,adding deflector roll,friction seperating,static electricity seperating.Previous reseachers focused on the melt temperature,flow control pump,drafting force,quenching air speed etc,which can improve the uniformity of spunbond.However,the research about static electricity seperating device which is simple and effective is not enough.Especially in the domestic,it is rarely found the static electricity seperating device being applied to the practice due to its lack of reserch.In the overseas,related patents has been applied for many years and the technology has been applied to practice for many years also.This paper redefined the index of uniformity for nonwovens and then simulated the electric filed distribution between the needle plate and grounded roll by finite element software Comsol Multiphysics.Finally orthogonal visual analysis was used to analyze the relationships between the index of uniformity and three parameters of static electricity seperating device.The research shows that voltage has significant influence on uniformity of spunbond,current can influence the iniformity also,and the distance between needle plate and grounded roll can not influence the results as voltage and current.The optimum parameters are respectively:voltage 26KV,current 0.4mA,distance50mm,which can resulte the best distribution for films of sponbond.In this paper CV of gram weight,thickness and air permeability were used to redefine the uniformity by the Fuzzy Logic Toolbox in Matlab and the index of uniformity was obtained.Secondly,two-dimensional model was modeled by finite element software Comsol Multiphysics by which the electric filed between needle plate and grounded roll was simulated.The result shows that:the needle and the voltage have significant influence on the electric filed between needle and grounded roll.Meanwhile,the needle plates should be installed close to the PET films as far as possible.Thirdly,orthogonal visual analysis was used to analyze the result and shows that:static electricity seperating device can improve the uniformity of thin PET spunbond significantly;significant levels of thress parameters for the index of uniformity was obtained;voltage influence the index significantly,current takes the second place,distance between needle plate and grounded roll can not influence the index of uniformity.The optimum parameters are respectively:voltage 26KV,current 0.4mA,distance50mm,which can resulte the best distribution for films of sponbond.Finally,the orientation of PET spunbond was analyzed and it was obtained that:the angles of the broken trails with the level line for PET spunbond can be a useful index to evaluate the quatity of filaments of cross direction.