CONTINUOUS EXTRUSION PRODUCTION OF MICROCELLULAR RIGID PVC

摘要

This study investigated the effect of PVC formulation on the cell morphology of rigid PVC foamed with supercritical CO_2 in a continuous extrusion process. Cell morphology was controlled by blending two acrylic based processing aids (all-acrylic foam modifier K-400 and acrylic-based impact modifier KM-334) using a mixture design. The experimental results indicated that fusion is not the only criterion to control the density or expansion achieved in microcellular rigid PVC foams. The melt must have a viscosity low enough to allow bubble formation and growth as well as melt elasticity/strength high enough to prevent cell coalescence.