In the PVC foam sheet extrusion process, the basic problems encountered can be grouped into four categories: first, the stability; second, the melt strength issues; third, lubrication problem; Fourth dispersion issues. In these four categories of issues, especially the first three categories of issues are mutual restraint, and influence crossly, while it is sometimes difficult to immediately distinguish from the surface phenomena of pvc foam boards. Lack of stability will affect the entire board, and the foam board will be yellow with large brittleness.
The deficiency of melt strength can lead to huge cell in the foam sheet and long longitudinal section bubble. The most direct way to determine whether the melt strength is insufficient is to press sheet wrapping the roller with your fingers and you can feel elasticity in the excellent melt strength. If it is difficult to bounce after the press, which means the poor melt strength.
The deficiency of melt strength can lead to huge cell in the foam sheet and long longitudinal section bubble. The most direct way to determine whether the melt strength is insufficient is to press sheet wrapping the roller with your fingers and you can feel elasticity in the excellent melt strength. If it is difficult to bounce after the press, which means the poor melt strength.