Process for the obtainment of a polyolefin composition

A process for obtaining a polyolefin composition comprising:

• A) contacting in a first polymerization step comprising a pressurized reactor propylene and optionally ethylene optionally in gas phase and a catalyst system to obtain an overall content of a first component (a) ranging from 25-70 wt %, based on the total wt % of the polyolefin composition, wherein the first component (a) is a propylene homopolymer, or a propylene-ethylene copolymer comprising 0.1-10 wt % of ethylene;
• B) further contacting in a second polymerization step comprising the pressurized reactor of step A) ethylene and at least one C3-C20 alpha olefin optionally in gas phase and the catalyst system to obtain an overall content of a second component (b) ranging from 27-70 wt %, based on the total wt % of the polyolefin composition, wherein the second component (b) is an ethylene copolymer comprising 15-70 wt % ethylene and at least one C3-C20 alpha-olefin, and an overall content of a third component (c) ranging from 3-20 wt %, based on the total wt % of the polyolefin composition, wherein the third component (c) is polyethylene homopolymer or copolymer comprising 95-99.9 wt % ethylene and at least one C3-C20 alpha-olefin, wherein the at least one C3-C20 alpha-olefin comonomer is the same used in component b) to form a polyolefin composition;
• and
• C) discharging the polyolefin composition:
• wherein the catalyst system comprises:
• i) a metallocene compound of the general formula (I):
• wherein M is selected from the group consisting of titanium, zirconium and hafnium;
• X, whether the same or different, is selected from the group consisting of hydrogen, a halide, an —R, —OR, —SO3CF3, —CO2R, —SR, —NR2 and —PR2 group, wherein R is selected from the group consisting of a linear or branched, cyclic or acyclic, C1-C40 alkyl, C2-C40 alkenyl, C2-C40 alkynyl, C6-C40 alkylaryl and C7-C40 alkylaryl and C7-C40 arylalkyl radicals;
• optionally comprising heteroatoms from Groups 13-17 of the Periodic Table of Elements;
• R1, R2, R3, R4, R5, R6 and R7, equal to or different from each other, are selected from the group consisting of hydrogen and C1-C40 hydrocarbon radicals optionally comprising heteroatoms from Groups 13-17 of the Periodic Table of Elements;
• or two or more groups between R1, R2, R3, R4, R5 and R6 can be fused to form a saturated or unsaturated, 5- or 6-membered rings and optionally comprise C1-C20 alkyl radical substituents;
• ii) at least one iron complex of the general formula (II):
• wherein the radical X1 is selected from the group consisting of hydrogen, a halide, —R, —OR, —SO3CF3, —CO2, —SR, —NR2 and —PR2 groups, wherein R is selected from a linear, branched, saturated and/or unsaturated C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl and C7-C20 arylalkyl radical, optionally containing heteroatoms from Groups 13-17 of the Periodic Table of Elements;
• or X1 can optionally form a substituted or unsubstituted butadienyl radical or an OR′O group, wherein R′ is a divalent radical selected from C1-C20 alkylidene, C6-C40 arylidene, C7-C40 alkylarylidene and C7-C40 arylalkylidene radicals;
• D is an uncharged donor;
• s is 1, 2, 3 or 4,
• t ranges from 0 to 4;
• R8, equal to or different from each other, are selected from the group consisting of hydrogen and C1-C40 hydrocarbon radicals optionally containing heteroatoms belonging to Groups 13-17 of the Periodic Table of Elements;
• R10, equal to or different from each other, are selected from the group consisting of hydrogen and C1-C40 hydrocarbon radicals optionally containing heteroatoms belonging to Groups 13-17 of the Periodic Table of Elements;
• R9, equal to or different from each other, are selected from the group consisting of hydrogen and C1-C40 hydrocarbon radicals optionally containing heteroatoms belonging to Groups 13-17 of the Periodic Table of Elements;
• and
• iii) an alumoxane or a compound capable of forming an alkyl cation with complexes of formula (I) and (II).