Polypropylene-based article having an increased surface tension retention

A process for the production of a polypropylene based article having improved surface tension retention, the process comprises:

• A) providing a metallocene-catalysed propylene-ethylene random copolymer (RACO) having
• (a) an ethylene content in the range of from 1.0 to 10.0 wt.-% based on the total weight of the propylene-ethylene random copolymer;
• (b) a melt flow rate MFR2 (230° C./2.16 kg) measured according to ISO 1133 in the range of from 1.0 to 20.0 g/10 min;
• (c) a melting temperature Tm as determined by DSC according to ISO 11357 of from 115 to 150° C.;
• (d) a xylene cold soluble (XCS;
• ISO 16152, 2005;
• 25° C.) fraction of from 0.1 wt.-% to 5.0 wt.-% and
• (e) a content of 2,1 regio-defects in the range from 0.05 to 1.5, mol % as determined by 13C-NMR spectroscopy
• B) forming an article out of the metallocene-catalysed propylene-ethylene random copolymer (RACO) with a thickness in the range of from 1.0 to 1000 μm and
• C) subjecting one or more surface(s) of the article to a treatment that increases the surface tension, to yield a polypropylene based article having improved surface tension retention, wherein the metallocene-catalysed propylene-ethylene random copolymer (RACO) is the sole polymer used for forming the article.