| abstract |
The present application relates to copolymer compositions and copolymerization processes. The process may use two different metallocene catalysts: one capable of producing high molecular weight copolymers; and a lower molecular weight copolymer suitable for preparing a copolymer having at least a portion of the vinyl terminations, and copolymer compositions prepared therefrom. The copolymer composition may comprise (1) a first ethylene copolymer fraction having a high molecular weight, exhibiting a branched topology, and having a relatively low ethylene content (based on the weight of the first ethylene copolymer fraction); and (2) a second ethylene copolymer fraction having a low molecular weight, exhibiting linear rheology, and having a higher ethylene content (based on the weight of the second ethylene copolymer fraction). It is believed that the unique combination of these properties provides a copolymer composition with a favorable combination of viscosity modifying properties, such as shear thinning and fuel economy, as well as high thickening efficiency. |