Transparent thin wall packaging material with improved stiffness and flowability

Heterophasic polypropylene resin having an MFR (2.16 kg, 230° C.) of more than 27 g/10 min, determined according to ISO 1133 comprising

• a propylene homo- or copolymer matrix (A) and an ethylene-propylene rubber phase (B) dispersed within the matrix,
• wherein the heterophasic polypropylene resin has
• a fraction insoluble in p-xylene at 25° C. (XCU) in an amount of 75 to 85 wt.-% with a weight average molecular weight of 110 to 190 kg/mol measured by GPC analysis according to ISO 16014-1, and 4, the fraction insoluble in p-xylene at 25° C. (XCU) containing monomer units derived from ethylene in an amount of 12.0 to 21.0 wt.-% and
• a fraction soluble in p-xylene at 25° C. (XCS) in an amount of 15 to 25 wt.-% having an intrinsic viscosity of 1.4 to 2.0 dl/g, determined according to DIN EN ISO 1628-1 and −3 and being composed of propylene monomer units in an amount of 40 wt.-% or more, and having a glass transition temperature Tg as measured by DSC according to ISO 6721-7 at a compression moulded sample consisting of the XCS fraction in the range of −60 to −50° C.

Heterophasic polypropylene resin obtainable by a quadruple stage reactor process, whereby

• the first reactor is a loop reactor operated under conditions to produce a propylene homo- or copolymer (A) being composed of propylene monomer units in an amount of at least 95 wt.-%, and an MFR (2.16 kg, 230° C.) of more than 60 g/10 min, and a xylene solubility of 3.0 wt. % or less,
• the obtained product from the bulk reactor being fed to a first gas phase reactor
• the first gas phase reactor being operated
• at a temperature of 65 to 75° C.,
• a pressure of 1900 to 2300 kPa, and
• a H2/C3 ratio of 10 to 16 mol/kmol,
• a C2/C3 ratio of 1100 to 1500 mol/kmol
• the obtained product from the first gas phase reactor then being fed to a second gas phase reactor,
• the second gas phase reactor being operated
• at a temperature of ±10° C. when compared with the first gas phase reactor,
• at a pressure of 1800 to 2300 kPa,
• a C2/C3 ratio of 1600 to 2000 mol/kmol,
• a H2/C2 ratio mol/kmol of 400 to 500 mol/kmol
• the obtained product from the second gas phase reactor being fed to a third gas phase reactor,
• the third gas phase reactor being operated
• at a temperature of 5° C. to 15° C. higher than the temperature in the first gas phase reactor,
• at a pressure of 2300 to 2700 kPa,
• a C2/C3 ratio of 300 to 420 mol/kmol,
• a H2/C2 ratio of 375 to 450 mol/kmol
• optionally subjecting the product from the third gas phase reactor to a degassing step,
• and compounding the product obtained from the third gas phase reactor or the degassed product in an amount of 70.5 to 84.5 wt.-% with respect to the final heterophasic polypropylene resin
• with an ethylene homo- or copolymer having a density measured according to ISO 1183 of less than 930 kg/m3 in an amount of 15 to 24.5 wt.-% with respect to the final heterophasic polypropylene resin
• in the presence of stabilisers in an amount of 0.5 to 5.0 wt with respect to the final heterophasic polypropylene resin.