Impact-modified polypropylene

A process for the preparation of a polymer composition comprising

• (i) providing a polypropylene matrix, wherein the polypropylene constituting the matrix is selected from the group consisting of a propylene homopolymer, a propylene copolymer having comonomer units derived from ethylene and/or C4 to C20 olefins, and any mixture thereof, wherein the polypropylene matrix is present in an amount of at least 60 wt %, based on the weight of the polymer composition;
• and said polypropylene matrix has a melt flow rate (MFR) of 10-30 g/10 min and a molecular weight distribution (MWD) of 5-8,
• (ii)providing a first elastomeric phase for disparing within the matrix and having glass transition temperature Tg1, measured with dynamical mechanical thermal analysis according to ISO 6721-2, within the range of −58° C. to −64° C., wherein the first elastomeric phase comprises an ethylene copolymer having comonomer units derived from C3 to C8 olefins, wherein the first elastomeric phase is non-crosslinked, wherein the first elastomeric phase is present in an amount of 10 to 30 wt %, based on the weight of the polymer composition;
• (iii)providing a second phase for dispersing within the matrix, wherein the second elastomeric phase is crosslinked polybutadiene and has a glass transition temperature Tg2, measured with dynamical mechanical thermal analysis according to ISO 6721-2, within the range of −75° C. to −85° C., wherein the second elastomeric phase, is present in the form of discrete particles having a mean particle size from 250 to 500 nm, wherein the second elastomeric phase is present in an amount of 10 to 17 wt %, based on the weight of the polymer composition,
• whereiin the differnce between Tg1 and Tg2 is at least 20° C. to 25° C.,
• dispersing the first and the second elastomeric phases within the propylene homo- or copolymer constituting the matrix, wherein the first elastomeric phase is prepared separately, followed by the dispersion within the propylene homo- or copolymer constituting the matrix.

A process for the preparation of polymer composition comprising

• (i) providing a polypropylene matrix, wherein the polypropylene constituting the matrix is selected from the group consisting of a propylene homopolymer, a propylene copolymer having comonomer units derived from ethylene and/or C4 to C20 olefins, and any mixture thereof, wherein the polypropylene matrix is present in an amount of at least 60 wt %, based on the weight of the polymer composition;
• and said polypropylene matrix has a melt flow rate (MFR) of 10-30 g/10 min and a molecular weight distribution (MWD) of 5-8,
• (ii) providing a first elastomeric phase for dispersing within the matrix and having glass transition temperature Tg1, measured with dynamical mechanical thermal analysis according to ISO 6721-2, within the range of −58° C. to −64° C., wherein the first elestomeric phase comprises an ethylene copolymer having copolymer units derived from C3 to C8 olefins, wherein the first elastomeric phase is non-crosslinked, wherein the first elastomeric is present in an amount 10 to 30 wt %, based on the weight of the polymer composition, wherein the first elastomeric phase is in situ dispersed within the propylene homo- or copolymer constituting the matrix by reactor blending;
• (iii) providing a second elestomeric phase for dispersing within the matrix, wherein the second elastomeric phase is crosslinked polybutadiene and had a glass transition temperature Tg2, measured with dynamical mechanical thermal analysis according to ISO 6721-2, within the range of −75° C. to −85° C., wherein the second elastomeric phase is present in form of discrete particles having a mean particle ratze from 250 to 500 nm, wherein the second elastomeric phase is present in an amount of 10 to 17 based on the weight of the polymer composition,
• (iv) dispersing the second elastomeric phase within the propylene homo or copolymer constituting the matrix,
• wherein the difference between Tg1 and Tg2 is at least 20° C. to to 25° C.

A shaped article, comprising a polymer composition comprising

• (i) a polypropylene matrix, wherein the polypropylene matrix is present in an amount of at least 60 wt %, based on the weight of the polymer composition;
• and said polypropylene matrix has a melt flow rate (MFR) of 10-30 g/10 min and a molecular weight distribution (MWD) of 5-8,
• (ii) a first elastomeric phase dispersed within the matrix and having a glass transition temperature Tg1, measured with dynamical mechanical thermal analysis according to ISO 6721-2, within the range of −58° C. to −64° C., wherein the first elastomeric phase comprises an ethylene copolymer having comonomer units derived from C3 to C8 olefins, wherein the first elastomeric phase is non-crosslinked, wherein the first elastomeric phase is present in an amount of 10 to 30 wt %, based on the weight of the polymer composition, wherein the intrinsic viscosity of the first elastomeric phase is 1 to 3.5 dl/g to provide high impact strength at low temperature,
• (iii) a second elastomeric phase dispersed within the matrix, wherein the second elastomeric phase is crosslinked polybutadiene and has a glass transition temperature Tg2, measured with dynamical mechanical thermal analysis according to ISO 6721-2, within the range of −75° C. to −85° C., wherein the second elastomeric phase is present in the form of discrete particles having a mean particle size from 250 to 500 nm, wherein the second elastomeric phase is present in an amount of 10 to 17 wt %, based on the weight of the polymer composition,
• wherein the differnce between the Tg1 and Tg2 is at least 20° C. to 25° C.