Prediction of melt residual in batch type gas injection foaming process

In the batch type gas injection foaming process, there must exist some melt residual. A differential equation relating the particle content and gas injection depth in the batch type process was presented, by which the melt residual ratio was predicted with the stability criterion as the boundary condition. It was found that the particle diameter increased during the foaming process but the thickness of the foam cell wall can be regarded as a constant. The adsorption coefficient and the injection depth were found to have an inverse relationship, with an exponential of −0.89. Based on the adsorption coefficient at different injection depth, the residual ratio of the melt containing given size particles was able to be predicted. To decrease melt residual needs to increase the particle content and the initial injection depth, and the particle diameter and the critical coverage ratio should be decreased.