Abstract: An improved process for pelletizing thermoplastic material, particularly ultra low melt viscosity thermoplastic polymer, using an underwater pelletizer adapted to prevent extruded material from agglomerating in the pelletizer, which pelletizer comprising a cutting assembly having (1) a shroud fixedly mounted on the outer periphery of the cutting assembly thereby preventing pellets from being trapped between the die face and the cutting assembly; and (2) novel knives contoured to conform in their angular positions to the curvature of the shroud to avoid pellet agglomeration.

Abstract: An improved underwater pelletizer adapted to prevent extruded material from agglomerating in an pelletizing assembly, which pelletizer includes a cutting assembly having (1) a shroud fixedly mounted on the outer periphery of the cutting assembly thereby preventing pellets from being trapped between the die face and the cutting assembly; and (2) novel knives contoured to conform in their angular positions to the curvature of the shroud.

Abstract: A process for making polymer pellets comprising unreacted free radical generator which can be degraded upon thermal treatment to form an ultra low melt viscosity polyolefin, which process comprises the steps of adding polyolefin and free radical generator required for the degradation in the extruder to the first half section of an extruder and injecting, optionally through a side-arm extruder, another portion of free radical generator near the exit of the extruder to provide a sufficient amount of unreacted free radical generator in the pellets produced, and followed by pelletizing the resulting molten mixture to form uniform non-sticky pellets.

Abstract: An improved underwater pelletizer adapted to prevent extruded material from agglomerating in an pelletizing assembly, which pelletizer includes a cutting assembly having (1) a shroud fixedly mounted to the surface of the recess in the center of the die ring thereby preventing pellets from being trapped between the die face and the cutting assembly; and (2) novel knives contoured to conform in their angular positions to the curvature of the shroud.