Acrylic processing aid for Foaming
PVC foaming regulator is actually acrylic processing aid, it has all the basic characteristics of the PVC processing aids, the only difference is that the molecular weight of PVC foaming regulator is much higher than that of general- Acrylic processing aids.
ACR processing aids have the effect of promoting PVC melting, improving surface glossiness, improving melt elasticity, and enhancing the elongation and strength of melt. It is helpful to cover bubbles and prevent hole collapse. The molecular weight of Foam regulator and dosage of foamed sheet density has great effect: with the increase of molecular weight, PVC melt strength increased, the density of foamed sheet can do less, and increase the dosage of the regulator has the same effect. But the effect is not linear, and the increase in molecular weight or increase in dosage is not very obvious, and the density will tend to be constant.
Important relationship between foam regulator and foaming agent, the density of foamed sheet with foaming regulator is a balance point, in this balance, density of foamed sheet is not affected by the influence of foaming agent content, are held constant, also is to increase the dosage of foaming agent can't reduce the density, the cause of this phenomenon is under a certain amount of foam regulator dosage, PVC melt strength is limited, too much gas bubble hole collapse or merger.