Claims
- 1. A process for the preparation of a propylene polymer, the propylene polymer being a fractionable propylene polymer, directly obtainable from the polymerization reaction of propylene, having the following characteristics:
- (a) content of isotactic pentads (mmmm) comprised between 25% and 85%;
- (b) ratio M.sub.w /M.sub.n,<5;
- said polymer containing from 10% to 70% by weight based on the total weight of said polymer of a fraction soluble in boiling diethylether, said fraction having a content of isotactic pentads (mmmm) comprised between 5% and 25%, and from 30% to 90% by weight based on the total weight of said polymer of a boiling-heptane-insoluble fraction, which is soluble in xylene at 135.degree. C., said fraction having a content of isotactic pentads (mmmm) comprised between 50% and 99%;
- the process comprising comprising the polymerization reaction of propylene, in a polymerization medium consisting essentially of liquid propylene, in the presence of a catalyst comprising the product of the reaction between:
- (A) a metallocene compound of formula (1): ##STR6## wherein on each indenyl group the R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 substituents, same or different from each other, are hydrogen atoms, C.sub.1 -C.sub.20 alkyl radicals, C.sub.3 -C.sub.20 cycloalkyl radicals, C.sub.2 -C.sub.20 alkenyl radicals, C.sub.6 -C.sub.20 -aryl radicals, C.sub.7 -C.sub.20 alkylaryl radicals, or C.sub.7 -C.sub.20 arylalkyl radicals, optionally two adjacent R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 substituents on the same ring can form a cycle comprising 5 to 8 carbon atoms and, furthermore, substituents R.sup.1 can contain Si or Ge atoms;
- M is a transition metal of group IVb, Vb, or VIb of the Periodic Table of the Elements;
- substituents X, the same or different from each other, are hydrogen atoms, halogen atoms, --R.sup.8, --OR.sup.8, --SR.sup.8, NR.sup.8.sub.2, or --PR.sup.8.sub.2 groups, wherein substituents R.sup.8 are C.sub.1 -C.sub.20 alkyl radicals, C.sub.3 -C.sub.20 cycloalkyl radicals, C.sub.2 -C.sub.20 alkenyl radicals, C.sub.6 -C.sub.20 -aryl radicals, C.sub.7 -C.sub.20 alkylaryl radicals, or C.sub.7 -C.sub.20 arylalkyl radicals, and can contain Si or Ge atoms; and
- (B) an alumoxane, or one or more compounds able to give a metallocene alkyl cation.
- 2. The process according to claim 1, wherein the polymerization temperature is comprised between 20.degree. C. and 40.degree. C.
- 3. The process according to claim 1 wherein, in the metallocene compound of formula (I), all the substituents R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are hydrogen atoms.
- 4. The process according to claim 1 wherein, in the metallocene compound of formula (I), the transition metal M is selected among titanium, zirconium and hafnium.
- 5. The process according to claim 1 wherein, in the metallocene compound of formula (I), the substituents X are chlorine atoms or methyl radicals.
- 6. The process according to claim 1, wherein the alumoxane is methylalumoxane.
- 7. The process according to claim 4 wherein the transition metal is zirconium.
Priority Claims (2)
Number |
Date |
Country |
Kind |
MI94A2566 |
Dec 1994 |
ITX |
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MI94A2567 |
Dec 1994 |
ITX |
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Parent Case Info
This application is a divisional of U.S. Patent application Ser. No. 08/574,495 filed Dec. 19, 1995 now U.S. Pat. No. 5,747,621.
US Referenced Citations (13)
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WOX |
Non-Patent Literature Citations (2)
Entry |
J.A. Ewen, "Mechanisms of Stereochemical Control in Propylene Polymerization with Soluble 4B Metallocene/Methylalumoxane Catalysts", Journal of the American Chemical Society, vol. 106, No. 21, Oct. 17, 1984 pp. 6355-6364. |
Llinas et al. "Macromolecules" 1992, 25, 1242-1253. |
Divisions (1)
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Number |
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Parent |
574495 |
Dec 1995 |
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