| 摘要 |
<p>Process for the preparation of a propylene copolymer, said process is a sequential polymerization process comprising at least two reactors connected in series,
wherein said process comprises the steps of (A) polymerizing in a first reactor propylene and optionally ethylene and /or a C 4 to C 12 ±-olefin, obtaining a polypropylene fraction (A),
(B) transferring said polypropylene fraction (A) and unreacted comonomers from the first reactor into a second reactor,
(C) feeding to said second reactor propylene and ethylene and /or a C 4 to C 12 ±-olefin,
(D) polymerizing in said second reactor and in the presence of said polypropylene fraction (A) propylene and ethylene and /or a C 4 to C 12 ±-olefin, obtaining a propylene copolymer fraction (B), said polypropylene fraction (A) and said propylene copolymer fraction (B) form the propylene copolymer,
wherein further
€¢ the temperature in the first reactor (R-1) is of more than 70 °C to equal or below 90 °C,
€¢ the temperature in the second reactor (R-2) is of equal or more than 80 °C to equal or below 95 °C,
€¢ in the first reactor (R-1) and second reactor (R-2) the polymerization takes place in the presence of a solid catalyst system (SCS) having a surface area measured according to ASTM D 3662 of less than 30 m 2 /g and/or a pore volume measured according to ASTM 4641 of less than 1.0 ml/g, wherein further
said solid catalyst system comprises a transition metal selected from one of the groups 4 to 6 of the periodic table (IUPAC), a metal which is selected from one of the groups 1 to 3 of the periodic table (IUPAC), and an internal electron donor (ID), and
said propylene copolymer has a melt flow rate MFR 2 (230 °C) of equal or more than 65 to equal or below 200 g/10min, and a comonomer content in the range of equal or more than 1.5 to equal or below 8.0 wt.-%.</p> |
