Abstract: The disclosure relates to an improvement in multiple spindle, single drive, rotary indexing machine tool systems. The basic machine comprises a fixed circular base and a central, upwardly projecting column. An indexing circular worktable is mounted on the base, for incremental, rotary indexing movements about the central column. The worktable carries a number of rotatable, work-holding chucks or spindles, which are progressively indexable with the worktable from a loading station progressively through a series of rotationally displaced work positions. Pursuant to the invention, one of the work stations is arranged to be mechanically independent of the primary machine drive and is provided with a tool slide with independent, numerically controlled motors for X and Y axis tool movement, and a third independent motor for spindle rotation.

Abstract: A process for the preparation of ethylene-propylene block copolymers at improved catalyst productivity rates involving the formation of a propylene prepolymer by polymerization of propylene in liquid phase in the presence of a catalyst system containing titanium halide supported on magnesium halide and aluminum alkyl complexed with an electron donor. Ethylene and propylene are block polymerized onto the prepolymer in a vapor phase reaction zone in the presence of further added quantities of similar catalyst components. The product of the process has higher ethylene and block contents as compared to products formed with none or only one of the components being added to the vapor phase reaction zone.

Abstract: A process for the preparation of ethylene-propylene block copolymers at high catalyst productivity rates resulting in polymer products having improved impact strength-polymerized ethylene content relationship.

Abstract: A process for the preparation of ethylene-propylene block copolymers at high catalyst productivity rates resulting in polymer products having improved impact strength-polymerized ethylene content relationship. The improvement is obtained by reacting preformed propylene prepolymer still containing active catalyst residues with ethylene and propylene in a vapor phase reaction zone in the presence of additional aluminum trialkyl catalyst component introduced to the reaction zone. The polymer produced by the process exhibits excellent physical and mechanical properties.