Process for manufacture of low emission heterophasic polypropylene

Abstract

The invention relates to a process for the preparation of a heterophasic propylene copolymer consisting of a propylene-based matrix and a dispersed ethylene-a-olefin copolymer, comprising the steps of a) preparing the propylene-based matrix from propylene and optionally a C2 or C4-C12 α-olefin by contacting at least propylene and optionally C2 or C4-C12 a-olefin with a catalyst in a first gas-phase reactor at a temperature T1 and a pressure P1, b) subsequently preparing the dispersed ethylene-α-olefin copolymer from ethylene and a C3-C12 α-olefin by contacting the ethylene and the C3-C12 α-olefin with a catalyst in a second gas-phase reactor at a temperature T2 and a pressure P2, wherein T1-T2 is in the range from 6 to 25° C., wherein T1>T2, wherein PI and P2 are in the range from 22 to 30 bar to prepare a heterophasic propylene copolymer (A′).

Dependencies are inferred from the claim text.