Water-based extrusion primer for polyethylene

A method of manufacturing a multilayer laminate, comprising steps of:

• (i) providing a substrate comprising metal, polyethylene terephthalate, polyamide, polypropylene, polyamide or combinations thereof;
• (ii) applying an aqueous coating composition to at least one surface of the substrate, the aqueous coating comprising (a) at least one copolymer obtained by reacting at least one compound which is catechol or a derivative thereof with at least one polyethyleneimine and (b) water such that an amount of further components in the aqueous coating is below 5 wt.-%;
• (iii) subsequently drying the aqueous coating composition thereby forming a tack-free coating layer on the at least one surface of the substrate;
• then
• (iv) applying a polyolefin layer or polyolefin film onto the tack-free coating layer;
• and
• (v) applying pressure at 100 to 250° C. sufficient to melt the polyolefin layer or polyolefin film thereby forming a multilayer laminate;
• wherein the polyolefin layer or polyolefin film has a first surface and a second surface opposite the first surface, the first surface being corona or ozone treated and the polyolefin layer or polyolefin film being arranged such that the first surface contacts but does not adhere to the tack-free coating layer until step (v).