EPDM compounds for dynamic applications
AssigneeCooper-Standard Automotive Inc.
InventorsHans-Joachim Graf, Yuding Feng
Life of this patent
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Abstract
Vulcanized ethylene-propylene-diene (EPDM) rubbers are disclosed that are particularly suited for use in dynamic applications as a replacement for natural rubber parts. The ethylene-propylene-diene rubbers exhibit excellent thermal and oxidative resistance while displaying tensile strength and dynamic fatigue resistance comparable to similar compounds based on natural rubber. The ethylene-propylene-diene rubbers comprise a high molecular weight EPDM, a processing oil, a carbon black, and a cure system containing sulfur, tetramethylthiuram-disulfide and 2-mercaptobenzothiazole.
Claims15
A composition particularly adapted for use in dynamic applications comprising:
- a high molecular weight ethylene-propylene-diene (EPDM) polymer having an ethylene content of about 60% to about 80% by weight of the polymer;
- about 10 to about 60 phr of a carbon black;
- and
- a cure system comprising sulfur, tetramethylthiuram-disulfide, and 2-mercaptobenzothiazole, the sulfur present in the concentration of about 0.8 to about 1.2 phr and the tetramethylthiuram-disulfide present in the concentration of about 0.8 to about 1.0 phr.
A composition particularly adapted for use in dynamic applications comprising:
- a high molecular weight EPDM polymer having an ethylene content of about 65% to about 75% by weight, a weight average molecular weight (MW) of about 200,000 to about 220,000, a polydispersity of about 2.6 to about 3.0, a Mooney viscosity (ML (1+4) 125° C.) of about 85 to about 100, said high molecular weight EPDM polymer being oil extended with about 15 to about 25 phr oil;
- about 20 to about 50 phr of an N774 grade carbon black;
- about 20 to about 50 phr of a paraffinic oil;
- and
- a cure system comprising sulfur, tetramethylthiuram-disulfide, and 2-mercaptobenzothiazole in a concentration ratio of about 1.0/0.8/0.4 phr respectively.
A process for forming a vulcanized molded part, said process comprising the steps of:
- obtaining a high molecular weight ethylene-propylene-diene (EPDM) polymer having an ethylene content of about 60% to about 80% by weight of the polymer;
- adding about 10 to about 60 phr of a carbon black to said high molecular weight ethylene-propylene-diene polymer;
- and
- adding a cure system comprising sulfur, tetramethylthiuram-disulfide, and 2-mercaptobenzothiazole, the sulfur present in the concentration of about 0.8 to about 1.2 phr and the tetramethylthiuram-disulfide present in the concentration of about 0.8 to about 1.0 phr, to said high molecular weight ethylene-propylene-diene polymer to form a rubber compostion;
- processing said rubber composition to form the desired final shape of the molded part;
- and
- curing said rubber composition under conditions necessary to optimize the final properties of the vulcanized molded part.
Dependencies are inferred from the claim text.