Heterophasic polypropylene with high impact properties
View Patent ↗The present invention relates to a heterophasic polypropylene resin comprising a polypropylene homo- or copolymer matrix phase (A) and an ethylene-propylene copolymer phase (B) dispersed within the matrix, wherein the heterophasic polypropylene resin has a fraction insoluble in p-xylene (XCU) at 25° C. with an intrinsic viscosity of 2.0 dl/g or less, determined according to DIN EN ISO 1628-1 and -3, and a fraction soluble in p-xylene (XCS) at 25° C. having an intrinsic viscosity of 2.0 to 4.5 dl/g, determined according to DIN EN ISO 1628-1 and -3, and an amount of ethylene monomer units of 60 to 85 mol %, a heterophasic polypropylene composition comprising such a resin, a process for preparing that resin, and an article made thereof.
1. Heterophasic polypropylene resin
comprising a polypropylene homo- or copolymer matrix phase (A) and an ethylene-propylene copolymer phase (B) dispersed within the matrix,
wherein the heterophasic polypropylene resin has
a fraction insoluble in p-xylene (XCU) at 25° C. with an intrinsic viscosity of 2.0 dl/g or less, determined according to DIN EN ISO 1628-1and -3, and
a fraction soluble in p-xylene (XCS) at 25° C. having an intrinsic viscosity of 2.0 to 4.5 dl/g, determined according to DIN EN ISO 1628-1 and -3, and an amount of ethylene monomer units of 60 to 85 mol %.
2. Heterophasic polypropylene resin according to claim 1 wherein the XCU fraction has an amount of propylene comonomer units of at least 90 mol %.
3. Heterophasic polypropylene resin according to claim 1 wherein the XCU fraction has a weight average molecular weight Mw of 100 to 500 kg/mol, measured by GPC according to ISO 16014-1, and 4.
4. Heterophasic polypropylene base resin according to claim 1 wherein the XCU fraction has a molecular weight distribution MWD of 1.5 to 4.5.
5. Heterophasic polypropylene base resin according to claim 1 wherein the XCU fraction is present in an amount of 60 to 95 wt % of the polypropylene resin.
6. Heterophasic polypropylene resin according to claim 1 wherein the XCS fraction has a weight average molecular weight Mw of 200 to 650 kg/mol, measured by GPC according to ISO 16014-1, and 4.
7. Heterophasic polypropylene resin according to claim 1 wherein the XCS fraction is present in an amount of 5 to 40 wt % of the base resin.
8. Heterophasic polypropylene resin according to claim 1 wherein the resin has a MFR (2.16 kg, 230° C.) of at least 10 g/10 min, determined according to ISO 1133.
9. Heterophasic polypropylene resin according to claim 1 wherein the resin has a MFR (2.16 kg, 230° C.) of 100 g/10 min or less, determined according to ISO 1133.
10. Heterophasic polypropylene base resin according to claim 1 wherein the base resin has a Charpy notched impact strength at +23° C. of at least 25.0 kJ/m 2 , determined according to ISO 179-1/1eA.
11. Heterophasic polypropylene resin according to claim 1 wherein the resin has a Charpy notched impact strength at −20° C. of at least 5.0 kJ/m 2 , determined according to ISO 179-1/1eA.
12. Heterophasic polypropylene resin according to claim 1 wherein the resin has a brittle-to-ductile transition at a temperature of 10° C. or less, determined from Charpy instrumented impact strength according to ISO 179-2:2000.
13. Heterophasic polypropylene resin according to claim 1 wherein the resin has an instrumented falling weight impact at +23° C. of at least 15 J, determined according to ISO 6603-2.
14. Heterophasic polypropylene resin according to claim 1 wherein the resin has an instrumented falling weight impact at −20° C. of at least 15 J, determined according to ISO 6603-2.
15. Heterophasic polypropylene resin according to claim 1 wherein the resin has been produced in a multi-stage process.
16. Heterophasic polypropylene resin according to claim 1 wherein the resin has been produced in presence of a catalyst system comprising an asymmetric catalyst wherein the catalyst system has a porosity of less than 1.40 ml/g.
17. Heterophasic polypropylene resin according to claim 16 wherein the asymmetric catalyst is dimethylsilyl [(2-methyl-(4′-tert.butyl)-4-phenyl-indenyl)(2-isopropyl-(4′-tert.butyl)-4-phenyl-indenyl)]-zirconium dichloride.
18. Process for the production of a heterophasic polypropylene resin according to claim 1 wherein the propylene homo- or copolymer matrix phase (A) is prepared in a first stage, and the ethylene-propylene copolymer phase (B) is prepared in a second stage in presence of the first stage product.
19. Heterophasic polypropylene composition comprising a heterophasic polypropylene resin according to claim 1 and additives in an amount of up to 10 wt %.
20. Article comprising the heterophasic polypropylene resin according to claim 1 .
21. An Article comprising the heterophasic polypropylene composition according to claim 19 .