Patent ID: 8841390

Claim:
Method for the preparation of a heterophasic polypropylene (HECO) in a reactor facility, wherein (A) the reactor facility comprises in series (i) a first reactor system (1 st RS) comprising at least a slurry reactor (SR) and/or at least one gas phase reactor (GPR), (ii) a first conveying line (CL 1 ) connecting the first reactor system (1 st RS) with a second reactor system (2 nd RS), (iii) the second reactor system (2 nd RS) comprising at least one gas phase reactor (GPR) and an outlet (O), (iv) a second conveying line (CL 2 ) connecting the outlet (O) of the second reactor system (2 nd RS) with a purge bin (PB) comprising a feeder (F), (v) a conveying system (C) optionally comprising a powder silo (PS), (vi) the conveying system (C) being connected with the feeder (F) of the purge bin (PB), and (vii) optionally an extruder (E) connected with the conveying system (C), (B) the preparation of said heterophasic polypropylene (HECO) comprises the steps in the order of (a) producing in said first reactor system (1 st RS) the polypropylene matrix (M), (b) transferring at least a part of said polypropylene (M) to said second reactor system (2 nd RS) via the first conveying line (CL 1 ), (c) producing in said second reactor system (2 nd RS) in the presence of said polypropylene (M) the elastomeric copolymer (E) obtaining the heterophasic polypropylene (HECO), (d) discharging said heterophasic polypropylene (HECO) from said second reactor system (2 nd RS) via the outlet (O), (e) transferring said discharged heterophasic polypropylene (HECO) via the second conveying line (CL 2 ) to said purge bin (PB) comprising said feeder (F), and (f) transferring further said discharged heterophasic polypropylene (HECO) from said purge bin (PB) via said feeder (F) to said conveying system (C), optionally to the powder silo (PS) of the conveying system (C), (g) optionally extruding the heterophasic polypropylene (HECO) in the extruder (E) to pellets, (C) the produced heterophasic polypropylene (HECO) is provided with an additive (A), said additive (A) is fed to the produced heterophasic polypropylene (HECO) (α) at the outlet (O) of the second reactor system (2 nd RS), and/or (β) at the purge bin (PB), and/or (γ) at the feeder (F) of the purge bin (PB), and/or (δ) at the powder silo (PS), and/or (ε) at the second conveying line (CL 2 ) between the outlet (O) and the purge bin (PB), and/or (ζ) at the conveying system (C) between the feeder (F) and the powder silo (PS), and (D) the produced heterophasic polypropylene (HECO) after being treated with the additive (A) (i) has a xylene cold soluble fraction (XCS) of at least 15 wt.-% and (ii) comprises a polypropylene matrix (M) and dispersed therein an elastomeric copolymer (E).