Patent ID: 8097682
Filing Date: 2012-01-17
Classification: C08F,C08L,Y10S

Abstract:
1. A 1-butene/propylene crystalline copolymer composition having a content of propylene derived units from 4 to 10% by weight, wherein at least 50% of the crystalline polymer is present in the thermodynamically stable, trigonal Form I after 5 hours of the first melting at room temperature; said composition having i) isotactic pentads (mmmm) measured by ii) a melting point (Tm(II)) higher than 70° C.; iii) a distribution of molecular weight Mw/Mn equal to or lower than 4; and iv) a solubility in xylene at 0° C. higher than 75%; said composition obtained by polymerizing 1-butene and propylene in the presence of a catalyst system obtained by contacting: a) at least a metallocene compound of formula (Ia) in the meso or meso-like form:  M is an atom of a transition metal selected from those belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table of the Elements;  p is an integer from 0 to 3, being equal to the formal oxidation state of the metal M minus 2;  X, same or different, is a hydrogen atom, a halogen atom, or an R, OR, OSO  L is a divalent C  R  T, equal to or different from each other, is a moiety of formula (IIa), (IIb) or (IIc):  wherein the atom marked with the symbol * bonds the atom marked with the same symbol in the compound of formula (Ia); and wherein at least one T group has formula (IIb) or (IIc);  R  R  R  R b) at least a metallocene compound of formula (Ib) in the racemic (rac) or racemic-like form  wherein the atoms marked with the symbol * bonds the atom marked with the same symbol in the moieties of formula (IIa), (IIb) or (IIc); and c) an alumoxane or a compound capable of forming an alkyl metallocene cation, wherein the ratio between the racemic or the racemic like form and the meso form or the meso-like form ranges from 20:80 to 80:20.