Abstract: A high output extruder screw which produces throughputs at lower temperatures and lower specific energy input. The screw has a feed section, a first short transition section, a first metering section, a second short transition section and a second metering section wherein the screw diameter increases from the feed section to the second metering section. There is also provided a method for extruding specific ethylene polymers.

Abstract: Method and apparatus are disclosed for the low energy melting, extrusion and pumping of material comprising feeding, metering, melting and mixing of such materials in an extruder having a melter screw and subsequently passing the resultant extrudate, through breaker plate and adapter means, to and through a rotary gear pump and, in turn, to a die member.

Abstract: A process comprising forming an extrudate, preferably in the form of a film, from an ethylene polymer which, in an extruder, melts rapidly and experiences slow shear thinning by melt extruding said polymer through an extruder having an extrusion screw therein with a length to diameter ratio of between about 15:1 to 21:1.

Abstract: A novel extruder screw having at least three segments wherein the pitch remains constant in each segment and changes abruptly from one segment to the following segment and wherein the pitch ratio divided by the depth ratio is greater than 2/3.

Abstract: Method for dispersing a fluid additive within only a portion of a stream of thermoplastic material comprising the steps of(a) flowing said stream of thermoplastic material into a channel having walls of substantially circular cross section, into which there has been placed a rotating mixer head having in the surface thereof a plurality of alternate lands and grooves each of said lands and grooves having an upstream end and a downstream end, said lands alternating with said grooves and being arranged in pairs, each of said pairs having a land in loose clearance with said wall followed by a land in close clearance with said wall, said mixer head having an unobstructed internal passage positioned therein over a substantial portion of its terminal length and a plurality of conduits severally connecting elongated zones between said lands pairs and said hollow internal passage, and(b) injecting said fluid additive into said channel at a position between said upstream and downstream ends of said lands and grooves.

Abstract: The invention provides apparatus for the production of cellular thermoplastic material comprising an extruder having a hollow barrel, screw means mounted in said barrel to advance material therethrough, mixer head means mounted in said barrel and gaseous blowing agent inlet means positioned in said barrel near the upstream end of said mixer head means, said mixer head means having in the surface thereof a plurality of alternate land and groove means, said land means having close clearance with the internal walls of said barrel near the upstream end thereof in the region of said blowing agent inlet means and alternately spaced and close clearance with said walls in the mixing region downstream of said blowing agent inlet means.