PROCESS FOR THE PREPARATION OF A COMPOSITION COMPRISING HETEROPHASIC PROPYLENE CO-POLYMER AND TALC

The invention relates to a process for the preparation of a composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc, wherein the heterophasic propylene copolymer consists of (a) a propylene-based matrix, wherein the propylene-based matrix consists of a propylene homopolymer and/or a propylene-α-olefin copolymer consisting of at least 70% by mass of propylene and up to 30% by mass of α-olefin based on the total mass of the propylene-based matrix, wherein the propylene-based matrix is present in an amount of 60 to 95 wt % based on the total heterophasic propylene copolymer and (b) a dispersed ethylene-α-olefin copolymer, wherein the dispersed ethylene-α-olefin copolymer is present in an amount of 40 to 5 wt % based on the total heterophasic propylene copolymer and wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene-α-olefin copolymer in the heterophasic propylene copolymer is 00 wt %, wherein the composition has a desired melt flow index in the range of 1 to 200 dg/min as measured according to ISO1133 (2.16 kg/230° C.) comprising the steps of (a) melt-mixing a propylene copolymer with a talc to obtain a masterbatch (b) melt-mixing the masterbatch with 1 the heterophasic propylene copolymer and a peroxide to obtain the composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc, wherein the amount of peroxide is chosen such that a composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc having the desired melt flow index is obtained.