Polypropylene composition suitable for extrusion coating
Polypropylene composition comprising a polypropylene base resin whereby the polypropylene base resin has a MFR (2.16 kg, 230° C., ISO 1133) of 8 to 24 g/10 min and a LAOS-NLF>2.8 whereby LAOS−NLF=|G′ 1 /G′ 3 | where G′ 1 —first order Fourier Coefficient, G′3—third order Fourier Coefficient.
1. A polypropylene composition comprising a polypropylene base resin wherein the polypropylene base resin has a MFR (2.16 kg, 230° C., ISO 1133) of 8 to 24 g/10 min and a Large Amplitude Oscillatory Shear Non-Linearity Factor (LAOS-NLF)>2.8 wherein
LAOS
-
N
L
F
=
G
1
′
G
3
′
where G′ 1 —first order Fourier Coefficient
G′ 3 —third order Fourier Coefficient.
2. A polypropylene composition according to claim 1 , wherein the polypropylene base resin has a strain hardening factor (SHF) of 2.3 to 7.0 when measured at a strain rate of 3.0 s −1 and a Hencky strain of 2.5.
3. A polypropylene composition according to claim 1 wherein the polypropylene base resin has a strain hardening factor (SHF) of 1.7 to 6.0 when measured at a strain rate of 1.0 s −1 and a Hencky strain of 2.0.
4. A polypropylene composition according to claim 1 wherein the polypropylene base resin has a F30 melt strength of 4.6 cN or higher at 200° C.
5. A polypropylene composition according to claim 1 wherein the polypropylene base resin is a polypropylene homopolymer.
6. A polypropylene composition according to claim 1 wherein the polypropylene base resin has a regio-inversion of above 0.1 mol-%.
7. A polypropylene composition according to claim 1 wherein the polypropylene base resin has a product of [F30 melt strength x MFR 2 (2.16 kg, 230° C., ISO 1133)] of 130 cNg/10 min or higher.
8. A polypropylene composition according to claim 1 having a melting temperature Tm in the range of 135 to 165° C.
9. A process for the production of a polypropylene composition according to claim 1 , comprising mixing an asymmetric catalyst derived polypropylene intermediate base resin having a MFR (2.16 kg, 230° C., ISO 1133) of 1.0 to 6.0 g/10 min with peroxide and a diene at a temperature of 20 to 90° C. for at least 2 minutes to form a pre-mixed material; and melt mixing the pre-mixed material in a melt mixing device at a barrel temperature in the range of 180 to 300° C.
10. A coated article including the polypropylene composition according to claim 1 as a coating layer.
11. A process for coating of an article comprising the lay down of a layer consisting of a polypropylene composition according to claim 1 .
12. The process according to claim 11 , wherein the draw down speed is above 300 m/min at a coating weight of 10 g of coating per square meter of substrate.
13. A method for the extrusion coating of an article comprising extrusion coating said article with a polypropylene composition according to claim 1 .