Patent ID: 6262195
Filing Date: 2001-07-17
Classification: C08F,C08L,Y10S

Abstract:
A multi-stage process for the polymerization of ethylene, and optionally one or more .alpha.-olefins comprising from 3 to 10 carbon atoms, for producing a polymer having broad MWD, said process comprising the following stages:(A) polymerizing ethylene, and optionally an .alpha.-olefin, in one or more reactors, in the presence of a catalyst comprising the reaction product between:(i) a solid component comprising a compound of a transition metal M.sup.I selected from Ti and V, not containing M.sup.I -.pi. bonds, and a halide of Mg in active form, optionally further comprising an electron-donor compound (internal donor);(ii) an alkyl-Al compound and optionally an electron-donor compound (external donor);(B) contacting the product obtained in stage (A), in any order whatever, with:(a) a compound capable of deactivating the catalyst of stage (A);(b) a zirconocene compound of formula (I): ##STR8##wherein R.sup.1, R.sup.2 R.sup.3 and R.sup.4, the same or different from each other, are selected from the group consisting of hydrogen, linear or branched, saturated or unsaturated, C.sub.1 -C.sub.20 alkyl, C.sub.3 -C.sub.20 cycloalkyl, C.sub.6 -C.sub.20 aryl, C.sub.7 -C.sub.20 alkylaryl and C.sub.7 -C.sub.20 arylalkyl radicals, optionally containing one or more Si or Ge atoms, or wherein two substituents of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 form a ring having from 4 to 8 carbon atoms;R.sup.5 and R.sup.6, the same or different from each other, are selected from the group consisting of linear or branched, saturated or unsaturated C.sub.1 -C.sub.20, C.sub.3 -C.sub.20 cycloalkyl, C.sub.6 -C.sub.20 aryl, C.sub.7 -C.sub.20 alkylaryl and C.sub.7 -C.sub.20 arylalkyl radicals, optionally containing one or more Si or Ge atoms, or wherein one pair of vicinal R.sup.6 substituents of the same indenyl group forms a ring having from 4 to 8 carbon atoms;m is an integer ranging from 0 to 2; n is an integer ranging from 0 to 4;the groups X, the same or different from each other, are hydrogen, halogen, --R, --OR, --SR, --NR.sub.2 or --PR.sub.2, wherein R is selected from the group consisting of linear or branched, saturated or unsaturated, C.sub.1 -C.sub.20 alkyl, C.sub.3 -C.sub.20 cycloalkyl, C.sub.6 -C.sub.20 aryl, C.sub.7 -C.sub.20 alkylaryl and C.sub.7 -C.sub.20 arylalkyl radicals, optionally containing one or more Si or Ge atoms; and(c) optionally an activating cocatalyst;(C) polymerizing ethylene, and optionally an .alpha.-olefin, in one or more reactors, in the presence of the polymer obtained from stage (B).