The discovery of transition metal catalysts, especially metallocene and constrained geometry catalysts, for the preparation of olefinic interpolymers has resulted in the synthesis of a wide range of new and useful olefinic interpolymer compositions. These transition metal catalysts are typically activated with boron containing activator packages. Following polymer formation, the catalyst-activator systems are deactivated by addition of water, methanol, or other catalyst deactivation agents. After isolation, the resulting olefinic interpolymer compositions retain residuals of the catalyst-activator systems and typically have dissipation factors greater than 0.10. A dissipation factor as low as possible is desired for olefinic interpolymer compositions in electrical applications. The olefinic interpolymer compositions can be acid washed or steam stripped to remove or reduce catalyst and activator residuals which further can lower the dissipation factor of the olefinic interpolymer composition to 0.01 or less depending on how the composition is washed or steam stripped. U.S. Pat. No. 3,819,591 provides examples of acid washing techniques and U.S. Pat. No. 3,076,795 and U.S. Pat. No. 3,590,026 provide examples of steam stripping techniques. While these techniques may effectively lower the dissipation factor, acid washing and steam stripping add an additional step and additional manufacturing costs to the preparation of the olefinic interpolymer compositions and are environmentally undesirable as each creates an additional waste stream, which must be disposed.
It has now been surprisingly discovered that by adding specific charge dissipation modifiers to olefinic interpolymer compositions prepared with transition metal catalysts and boron containing activator packages, the dissipation factors can be lowered to levels which are at least about 50% less than dissipation factors of the corresponding olefinic interpolymer compositions which have not been treated with the charge dissipation modifiers, thus providing simpler, lower cost, more environmentally friendly olefinic interpolymer compositions for electrical applications, particularly low and medium voltage wire and cable insulation and jacketing.
USPTO Backgrounds
USPTO Backgrounds