Abstract: A mixing apparatus for mixing thermoplastic compounds wherein the mixing body has a pair of parallel chambers with a pair of rotors rotatably journaled therein. Such mixer has at least one bore communicating the parallel chambers with atmosphere to vent gases from the central bore. A rotatable screw is mounted in the bore which upon rotation continuously feeds the mixed thermoplastic material back into the chambers but allows the gases generated to be vented out of such bore.

Abstract: Certain thermoplastic blends have substantially improved hot strength (i.e., cohesive strength and resistance to sagging or tearing during milling or other hot processing). The blends comprise (1) at least one ethylene-propylene (EP) or ethylene-propylene-diene (EPDM) polymer and (2) at least one highly crystalline polyallomer, and are useful for tubing, wire and cable insulation, molded items and the like.

Abstract: Certain thermoplastic polymer blends have tensile strengths greater than that of any one polymer component. The blends comprise (1) at least one ethylene-propylene-diene (EPDM) polymer, (2) at least one ethylene-ethyl acrylate (EEA) polymer, and (3) optionally, at least one polyethylene. The blends are prepared by mixing physically the polymer components under heat and shear conditions. No curing or crosslinking agents are needed to obtain the superior tensile strengths of the thermoplastic blends. The blends are useful to prepare tubing, sheet products, wire and cable insulation, molded items and the like.

Abstract: Certain thermoplastic polymer blends have tensile strengths greater than that of any one polymer component. The blends comprise (1) at least one ethylene-propylene-diene (EPDM) polymer, (2) at least one ethylene-propylene (EP) polymer, and (3) optionally, at least one polyethylene. The EPDM and EP polymers each have ethylene content, unstretched crystallinity, and Mooney viscosity within a specific range. The blends are prepared by mixing physically the polymer components under heat and shear conditions. No curing or crosslinking agents are needed to obtain the superior tensile strengths of the thermoplastic blends. The blends are useful to prepare tubing, wire and cable insulation, molded items and the like.

Abstract: EPDM polymers having a high ethylene length index (ELI) are physically blended with polyethylene polymers. The blends exhibit superior tensile strength, significantly better than that predicted from their additive individual effects. The thermoplastic polymer blends are useful to prepare molded products, tubing, liners, and like products.

Abstract: EPDM polymers having a high degree of unstretched crystallinity are physically blended with polyethylene and an ethylene-vinyl acetate copolymer to form thermoplastic polymer blends. The blends exhibit superior tensile strength, better than that predicted from the individual effects of the polymeric components alone. No curing or crosslinking agents are used. The thermoplastic blends are useful to prepare liners, tubing, molded products, and the like.