Ethylene/branched olefin copolymers

A method for preparing a compositionally uniform copolymer of ethylene having a composition distribution breadth index of within the range of 50% to less than 100% and from about 0.5 to about 10 mole percent of a 3-, 4-, or 5-lower-alkyl branched .alpha.-olefin comonomer having from 6 to about 30 carbon atoms, wherein the lower alkyl branch is closer to the .alpha.-olefin unsaturation than a terminal carbon atom in the longest straight chain of the comonomer, and wherein the copolymer has a density from about 0.85 to about 0.95 g/cm.sup.3, a weight average molecular weight from about 30,000 to about 1,000,000 daltons and a molecular weight distribution from about 2 to about 4, the method comprising:

• charging a reactor with ethylene and the branched .alpha.-olefin comonomer at reaction conditions in the presence of a catalyst system including a metallocene catalyst component and an activating component for activating the metallocene component, wherein the metallocene component has the formula:
• ##STR6## wherein M is Zr, Hf or Ti in its highest formal oxidation state:
• (C.sub.5 H.sub.5-y-x R.sub.x) is a cyclopentadienyl ring which is substituted with from zero to five substituent groups R, "x" is 0, 1, 2, 3, 4 or 5 denoting the degree of substitution, and each substituent group R is, independently, the radical selected from a group consisting of C.sub.1 -C.sub.20 hydrocarbyl radicals;
• substituted C.sub.1 -C.sub.20 hydrocarbyl radicals wherein one or more hydrogen atoms is replaced by a halogen radical, and amido radical, a phosphido radical, and alkoxy radical, an alkylborido radical or a radical containing a Lewis acidic or basic functionality;
• C.sub.1 -C.sub.20 hydrocarbyl-substituted metalloid radicals wherein the metalloid is selected from the Group IV A of the Periodic Table of Elements;
• and halogen radicals, amido radicals phosphido radicals, alkoxy radicals, alkylborido radicals, or a radical containing Lewis acidic or basic functionality;
• or (C.sub.5 H.sub.5-y-x R.sub.x) is a cyclopentadienyl ring in which two adjacent R-groups are joined forming C.sub.4 -C.sub.20 ring to give a saturated or unsaturated polycyclic cylcopentadienyl ligand;
• (JR'.sub.z-1-y) is a heteroatom ligand in which J is an element with a coordination number of three from Group V A or an element with a coordination number of two from Group VI A of the Periodic Table of Elements, each R' is, independently a radical selected from the group consisting of C.sub.1 -C.sub.20 hydrocarbyl radicals, substituted C.sub.1 -C.sub.20 hydrocarbyl radicals wherein one or more hydrogen atoms is replaced by a halogen radical and amido radical, an alkylborido radical, a phosphido radical, an alkoxy radical, and a radical containing a Lewis acidic or basic functionality;
• and "z" is the coordination number of the element J;
• each Q is, independently, any univalent anionic ligand, provided that where Q is a hydrocarbyl such Q is different than the (C.sub.5 H.sub.5-y-x R.sub.x) or both Q together are an alkylidene, a cyclometallated hydrocarbyl or a divalent anionic chelating ligand;
• "y" is 0 or 1 when "w" is greater than 0;
• "y" is 1 when "w" is 0;
• when "y" is 1, T is a covalent bridging group containing a Group IV A or V A element;
• L is a neutral Lewis base where "w" denotes a number from 0 to 3.