Patent ID: 6783710
Filing Date: 2004-08-31
Classification: B29B,B29C,B29K,Y10S

Abstract:
In a method for producing expandable plastic granulate from a plastic material and a fluid blowing agent that is only partially soluble in the plastic material when the plastic material is at an elevated temperature byheating the plastic material to the elevated temperature to form a plastic melt; dispersing the blowing agent in the melt to form a mixture; retaining the mixture for a predetermined time at the elevated temperature and pressure for a predetermined time interval; and thereafter cooling and granulating the mixture, the improvement comprising: providing a first static mixer in which the dispersing step is carried out and which subjects the mixture to intensive shearing; and providing a second static mixer in which the retaining step is carried out and which subjects the mixture to less intensive shearing than in the first static mixer.