8-Sila-4-stanna-s-tetrahydroindacenes as synthons for Me2Si-bridged zirconocenes: formation from biscyclopentadienyl silanes by reaction with aminostannanes
Alkyl-substituted bis(cyclopentadienyl)dimethylsilanes react with Me2Sn(NEt2)2 and with (Me2N)4Sn to yield correspondingly substituted, meso-configurated RS-8-sila-4-stanna-s-tetrahydroindacene and axially symmetric RR,SS-4-spiro-bis(8-sila-4-stanna-s-tetrahydroindacene) compounds, respectively, which are stereoselectively converted by reaction with ZrCl4 to the corresponding meso- and rac-configurated
Propylene-ethylene copolymer composition and process for producing the
申请人:Chisso Corpoation
公开号:US06005034A1
公开(公告)日:1999-12-21
A propylene-ethylene copolymer composition is obtained which has good moldability and an excellent balance of rigidity, toughness, and impact-strength. The composition has a melt flow rate of 10 to 300 g/10 minutes and is obtained by producing 60 to 95% by weight, based on the weight of whole polymer, of a propylene polymer having a melt flow rate (ASTM D1238) in the range of 100 to 1,000 g/10 minutes and having a ratio (Cf) of integrated values of the propylene polymer dissolved in o-dichlorobenzene at a temperature of lower than 112.degree. C., and a temperature of 112.degree. C. or higher, respectively, of 0.5 or less, by carrying out polymerization of propylene in the presence of a highly stereoregular catalyst and hydrogen in a polymerization step (I), and then producing 5 to 40% by weight, based on the weight of whole polymer, of an ethylene-propylene copolymer by feeding ethylene and propylene to the propylene polymer to react so that the content of ethylene becomes 30 to 80% by weight. Also provided is a propylene-ethylene copolymer composition comprising the composition mentioned above and a .alpha.-crystal and/or .beta.-crystal nucleator added therewith.