Role of ACR in PVC Foamed Sheet

ACR processing aids can promote the melting of PVC, improve the surface finish, improve the elasticity of the melt, and enhance the elongation and strength of the melt. It is conducive to covering bubbles and preventing bubble collapse. The molecular weight and amount of foaming regulator have a great influence on the density of the foam sheet: with the increase of molecular weight, the strength of PVC melt increases, and the density of the foam sheet can be lower, which has the same effect as the increase of the amount of regulator. However, this effect does not have a linear relationship. If you continue to increase the molecular weight or increase the dosage, the effect on reducing the density is not very obvious, and the density will tend to be constant.

There is an important relationship between the foaming regulator and the foaming agent. There is a balance point between the density of the foam sheet and the foaming regulator. Beyond this balance point, the density of the foam sheet is not affected by the content of the foaming agent and remains constant. That is, increasing the amount of the foaming agent cannot reduce the density. The reason for this is that the melt strength of PVC is limited with a certain amount of the foaming regulator, Excess gas causes the cell to collapse or coalesce.