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US 6,455,599 B1Granted
Process for the preparation of expanded polyvinylarene particles
AssigneeNOVA Chemicals (International) S.A.
InventorsMichel Florentine Jozef Berghmans, Karel Cornelis Bleijenberg, Alphonsus Catharina Gerardus Metsaars
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Abstract
Process for the preparation of expanded polyvinylarene particles in which polyvinylarene particles pre-expanded to an apparent density do ranging between 600 and 200 kg/m3 are impregnated by an inorganic gas, and the impregnated particles thus obtained are expanded to an apparent density of at least three times lower than do.
Claims10
Process for the preparation of expanded porous polyvinylarene particles, the steps comprising:
- a) pre-expanding unexpanded polyvinylarene particles that are impregnated with a blowing agent to an apparent density do ranging between 600 and 200 kg/M3 to form pores in said particles, said pores being of such a size that a reasonable amount of an inorganic gas can be impregnated into said pores of said particles;
- b) impregnating said inorganic gas into said pores of said pre-expanded particles;
- and
- c) expanding said particles of step b) to form said expanded polyvinylarene particles to an apparent density of at least three times lower than do.
1 more element
Dependencies are inferred from the claim text.