Rexene Corporation

Rexene Products Company

John R Bonser

Bennie M Lucas

V Krishnamurthy

Polymer compositions having improved resistance to thermoforming sag are disclosed. The compositions comprise a first and second portion selected from the group comprising polypropylene, propylene-ethylene copolymers and mixtures thereof wherein a first portion of the composition is (1) mixed with from about 500 to about 3000 ppm of antioxidant; and (2) irradiated with a dosage of from about 10 to about 20 Mrads gamma or electron beam of ionizing radiation in air, and the second portion of said polymer composition is non-irradiated. The first portion is present in an amount effective, from about 1.0% to about 10.0%, to increase the elasticity of the polymer composition in the molten state by at least 10% as compared to the second portion of said polymer composition.

Propylene compositions with improved resistance to thermoforming sag

Improved resin compositions for use in multiple cavity stretch blow molding processes comprising: (a) a propyleneethylene copolymer resin including from about 5% to about 15% of a second stage polymer characterized by a cycle time of T.sub.1, when used to produce containers in multiple cavity stretch blow molding processes; (b) from about 0.1% to about 1.0% of a nucleating agent prepared by irradiating in air a mixture of a propylene homo or copolymer and about 500 to about 3000 ppm of antioxidant with a sufficient amount of ionizing radiation to cause said nucleating agent to have a xylene insoluble content of at least 30%. The improved resin composition is characterized by a cycle time of T.sub.2 when used to produce containers in multiple cavity stretch blow molding processes such that the ratio of T.sub.2 /T.sub.1 is less than 0.95.

Growing community of inventors

Odessa, TX, United States of America

John R Bonser