Abstract: Provided for preparing thermoplastic polymer blends is (1) an apparatus comprising a grinder, a mixer, at least one material transfer device, a weigh scale, means for addition of additives to the mixer, a storage vessel, a processing device and means for feeding polymer to the processing device; and (2) a process comprising mixing a known amount of a first material with a desired amount of at least one additive based on a predetermined weight ratio of additive to first material to form individual batches of pre-mix, storing the pre-mix batches in a storage vessel, continuously feeding the pre-mix from the storage vessel to a processing device, adding a polymer stream to the processing device at a rate based on the first material feed rate to the processing device, optionally adding at least one vulcanizing agent stream to the processing device at a rate based on the polymer stream feed rate to the processing device and melt mixing all materials in the processing device to form a thermoplastic polymer blend.

Abstract: Described in one aspect is a process for preparing a low durometer thermoplastic vulcanizate composition comprising melt blending one or more thermoplastic polymer(s) with a cross-linkable elastomer under conditions of dynamic vulcanization; adding at or after the start of the melt blending at least one curative agent for the elastomer so as to cross-link the elastomer during the melt blending; introducing process oil into the melt blending before, during and/or after the addition of the curative agent; and, extruding a fully crosslinked thermoplastic vulcanizate having a Shore A Hardness of less than 25.

Abstract: The invention relates to a method of preparing a thermoplastic vulcanizate comprising: a) melt processing a blend of thermoplastic polymer and vulcanizable elastomer in a multi-screw extruder having at least three intermeshing screws, wherein said screws have 3-170 mixing zones, and said extruder having a L/D ratio of 15-100, and a screw profile that has 3 to 17 meshes per L/D; b) adding at least one curing agent to the melt-processed blend of a) in at least one location in the first 46% of the length of said extruder, or adding at least one curing agent to the melt-processed blend of a) in a second extruder, so as to initiate curing of the blend: and, curing at least partially said elastomer by reactive melt processing. Improved processing, reaction kinetics and efficiencies are achieved, as well as thermoplastic vulcanizate products having decreased weight gain when placed in mineral oils.