The Tensile Orientation Of The Wound Film

The orientation in the process of winding film production mainly occurs in the process of longitudinal and transverse stretching. After longitudinal stretching, the uniaxial longitudinal orientation of the polymer chain greatly improves the longitudinal mechanical properties of the sheet, while the transverse properties are reduced. After further transverse pulling, the polymer chain is biaxially oriented, which can improve the performance of PE winding film. However, during preheating and transverse stretching, the relaxation time of molecular chain is shortened due to the increase of temperature, which is conducive to the solution orientation. Coupled with the effect of transverse tensile force, the longitudinal orientation of molecular chain will be reduced to a certain extent, resulting in the decrease of longitudinal thermal shrinkage of the film.