| 摘要 |
<p>Process for producing propylene random copolymers with an MFR 2 in accordance with ISO 1133 (230°C, 2.16 kg) in the range of 0.1 to 200 g/10min and an ethylene and/or C 4 -C 12 alpha-olefin comonomer content in the range of 1 to 15 wt% of the propylene random copolymer, said process comprises the steps of
a) polymerising propylene and an ethylene and/or C 4 -C 12 alpha-olefin comonomer in a slurry reactor in the presence of hydrogen and a polymerisation catalyst system obtaining as slurry reactor product a first propylene copolymer component, 2 to 40 mol/kmol, and the hydrogen/propylene ratio being in the range of 0.1 to 30 mol/kmol,
b) transferring the slurry reactor product into a gas phase reactor
c) further polymerising propylene and an ethylene and/or C 4 -C 12 alpha-olefin comonomer in the presence of said slurry reactor product, the polymerisation catalyst system and additional hydrogen, 5 to 60 mol/kmol, and the hydrogen/propylene ratio being in the range of 2 to 200 mol/kmol,
d) optionally recovering the so produced propylene random copolymer for further processing,
said polymerisation catalyst system comprising
(i) a Ziegler-Natta procatalyst and
(ii) an organometallic cocatalyst and
(iii) an external donor represented by formula (I)
€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒSi(OCH 2 CH 3 ) 3 (NR 1 R 2 ) €ƒ€ƒ€ƒ(I)
wherein R 1 and R 2 can be the same or different and represent a hydrocarbon group having 1 to 12 carbon atoms,
and the use of the propylene random copolymer as matrix for soft heterophasic propylene copolymers.</p> |
