Active polystyrene film

A polystyrene film for applications in contact with food products, said film including at least one layer comprising:

• 64%-70% (w/wt) polystyrene crystal (PS) wherein the PS comprises PS with an MFI (Melt Flow Index) of between 10 g/10 min-40 g/10 min at 200°C. and 5 Kg (PS1) or PS with an MFI of 29/10 min-5 g/10 min at 200°C. and 5 Kg (PS2);
• 16% -30% (w/wt) ethylene copolymer with polar monomers (EMP) with a comonomer content of 15%-40% w/wEMP;
• an active substance selected from the group consisting of an antioxidant agent and an antimicrobial agent;
• 0.5%-2% (w/wt) migration agent (MA);
• and,
• 0-15% (w/wt) emulsifying agent (EA) with an HLB greater than 8, being 3%-15% (w/wt) when the active substance is an antimicrobial agent,
• wherein a PS/(EMP+EA) ratio is between 1.2 and 4.4, and
• wherein the foregoing percentages are given in percent by weight relative to a total weight of the layer (w/wt) or relative to a total weight of the EMP (w/wEMP).