PROCESS FOR THE PREPARATION OF A COMPOSITION COMPRISING HETEROPHASIC PROPYLENE COPOLYMER AND TALC

摘要

The invention relates to a Process for the preparation of a composition comprising a heterophasic 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 95wt% 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 5wt% 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 100wt%, wherein the composition has a desired melt flow index in the range of 1 to 200dg/min as measured according to ISO1133 (2.16 kg/230°C), wherein at least part of the talc is surface-modified and wherein the amount of talc in the composition is from about 0.5 to at most 5wt% based on the heterophasic propylene copolymer, comprising the step of (a) melt-mixing the heterophasic propylene copolymer with the talc and a peroxide, wherein the amount of peroxide is chosen such that a composition comprising a heterophasic propylene copolymer and talc having the desired melt flow index is obtained.