Patent ID: 7273571
Filing Date: 2007-09-25
Classification: B29C,B29L

Abstract:
1. A method for making a molded article; comprising the steps of: a) introducing polymeric material without a foaming agent into a mold having an inside surface; b) rotating the mold while heating the material to a first temperature, so as to form a molten shell with molten polymeric material from a portion of the polymeric material on the inside surface of the mold with an unmelted portion remaining inside the molten shell; c) subsequently causing a foaming agent alone to disperse within the mold and come into contact with the molten polymeric material after the polymeric material has formed the molten shell and mix with the remaining unmelted portion; and d) rotating the mold while heating the material to a second higher temperature, so as to allow the foaming agent to cause expansion of the remaining unmelted portion of the polymeric material, so as to form an expanded foam core within an interior region of the shell.