Directional flexibilization of expanded thermoplastic foam sheet for low temperature insulation

摘要

Flexibilized, rigid plastic foam sheets with improved properties particularly desirable for low temperature and cryogenic insulation can be prepared by mechanical compression of freshly expanded closed-cell thermoplastic foams. Thus an extruded foam sheet having a density of 20-100 kg/m3, a &upbar& y-axial size size of 0.05 to 1.00 mm and a &upbar& Y-axial compressive strength of at least 1.8 kg/cm2 is flexibilized with 0.25 to 240 hours of expansion to give a flexibilized foam with improved elongation, workability, crack resistance and water vapor barrier properties.