PVC film will have molecular orientation when calendered

In many cases, PVC film is a kind of material with high value, in the cover film of the car; in the transparent plastic film of skin care products; in the plastic wrap used in our family. All of these include the ingredients of pvc. It can be said that pvc is now ubiquitous and has been integrated into our lives, inadvertently helping us to complete some work. The current production of PVC transparent film needs a variety of processing to enter the market, and one type of processing is called calendering. Here we introduce the technology of this calendering.

???? Calendering actually means that when the material passes through two rotating cylinders facing each other, due to the strong shear stress and tensile stress, the PVC molecules will undergo molecular orientation along the calendering direction, so that the film will have different physical and mechanical properties. Anisotropy, this is the rolling effect. The stronger the rolling effect, the greater the shrinkage of the product during secondary processing. This is due to the fact that the macromolecules in the original orientation are restored to only the curled state due to heat or stress relaxation.