| 摘要 |
Reactor grade thermoplastic polyolefins with high flowability and excellent surface quality comprising (A) 40-90 wt % of a propylene homo- or copolymer matrix with an MFR in accordance with ISO 1 133 (230° C., 2.16 kg load) of >200 g/10 min and (B) 2-30 wt % of an elastomeric ethylene-propylene copolymer having an intrinsic viscosity IV (according to ISO 1628 with decalin as solvent) of ≦̸2.8 dl/g and an ethylene content of >50 to 80 wt % and (C) 8-30 wt % of an elastomeric ethylene-propylene copolymer having an intrinsic viscosity IV (according to ISO 1628 with decalin as solvent) of 3.0-6.5 dl/g and an propylene content of 50 to 80 wt %, the reactor grade thermoplastic polyolefins being obtainable by a multistage polymerization process with at least 3 polymerization steps in the presence of a catalyst system comprising (i) a Ziegler-Natta procatalyst which contains a trans-esterification product of a lower alcohol and a phthalic ester and (ii) an organometallic cocatalyst and (iii) external donor represented by formula (I) Si(OCH2CH3)3(NR1R2) wherein R1 and R2 can be the same or different a represent a hydrocarbon group having 1 to 12 carbon atoms, as well as the use of these reactor grade thermoplastic polyolefins and molded articles produced from them. |
