Abstract: An improved underwater pelletizer is provided. The improved pelletizer has sealed heat transfer tubes embedded within the extruder die to utilize the heat of the molten polymer entering the extruder die by efficiently transferring that heat to the die plate and die face of the pelletizer. Ceramic inserts and/or inserts of other insulating materials are provided adjacent the die plate to insulate the passages through which the molten polymer passes and to inhibit cooling of the polymer within the extruder die as it approaches the die plate. The insulating inserts are positioned behind, and abut, the die plate around the passages that deliver the molten polymer to the die plate. Water makeup is provided at the cutter blades of the pelletizer to prevent cavitation within the water housing so that pellets will not agglomerate within the water housing.

Abstract: An improved process for preparing extruded films from film-forming polymeric compositions based on vinylidene chloride copolymers and containing one or more inorganic particulate additives and to the films so prepared. The improvement comprises first preparing a preblend of the inorganic particulate additives and an alkali metal salt of an alkylaryl sulfonic acid and, then making an admixture of the preblend and the vinylidene chloride copolymers. The admixture so prepared is then formed into an extruded film by conventional techniques.

Abstract: An easily-movable plug seal that is susceptible to quick and ready longitudinal adjustment in the central, lengthwise bore of an internally differentially heated (or cooled) extruder screw for sequentially diverse and distinct heat controlled zones within the extruder barrel is comprised of at least a single, cup-like member that is adequately flexible and supple to be flared laterally outwardly and urged into tight wall contact to make a sealing engagement against the internal screw bore wall upon pressurization of the interior of the plug seal member by the heat transfer fluid being passed into and applied within the screw.

Abstract: A device for wrapping sheet, such as a foam panel, about a tubularly shaped object article, such as pipe sections of a pipeline. The device engages the substantially flat sheet and cams it about the curved pipe body circumference by pivoting yokes so as to cause the sheet to be wrapped about the pipe body. After the sheet is wrapped about the pipe body its free edges are fastened together so that the device can be removed.