Multi-Layer Slip Film for Printing and Lamination Processes

A method of making a heat sealable multi-layer film structure for multi-color printing or lamination processes, the method comprising the steps of:

• (a) forming the heat sealable multi-layer film by coextruding:
• (i) a core layer comprising a thermoplastic polymer and essentially no migratory slip agents;
• (ii) a functional layer on a side of the core layer, wherein the functional layer is a printable layer or a laminatable layer;
• and
• (iii) a heat sealable skin layer on a side of the core layer opposite the functional layer, the heat sealable skin layer comprising a thermoplastic polymer and a slip system, wherein the thermoplastic polymer comprises at least 60 wt % of propylene derived units, and
• wherein the slip system consists essentially of:
• (A) a silicone gum comprising less than or equal to 1500 ppmw of the sealant skin layer,
• (B) a wax which comprises less than or equal to 10 wt % of the sealant skin layer, or
• (C) a combination of the silicone gum and the wax, wherein the silicone gum comprises less than or equal to 1500 ppmw of the sealant skin layer and the wax comprises less than or equal to 10 wt % of the sealant skin layer;
• and
• (b) winding said film on to a spool or roll in which at least a portion of the heat sealable layer contacts the functional layer, wherein essentially none of the slip system in the heat sealable skin layer is transferred to the functional layer.