Patent ID: 7279225

Claim:
A continuous process for applying a polymer coating layer on a metal strip comprising the following steps: a) moving said metal strip through a processing line, b) pretreating a major surface of said metal strip with a first oxidizing flame, c) applying a thin liquid primer coat of 1.5 to 7.5 mg/ft 2 to said pretreated major surface wherein said thin liquid primer coat incorporates a corrosion inhibitor which is an organo-chromium or chromium compound to prevent oxidation on any said major surface of said metal strip, d) activating the exposed surface of said thin liquid primer coat with a second oxidizing flame and optionally a corona discharge, e) heating said metal strip to a first temperature, f) using an extrusion coating process to melt and apply a polymer extrudate onto said activated exposed surface of said thin liquid primer coat thereby creating a coated metal strip, g) wherein said extrusion coating process includes contacting said coated metal strip with a cooling roll, h) wherein said cooling roll has a temperature less than said polymer extrudate, and i) wherein said cooling roll has a surface finish suitable for imparting final desired surface attributes to the outside surface of said polymer extrudate, whereby said coated metal strip has desired coating characteristics and has satisfactory adhesion between said metal strip, said thin liquid primer coat, and said polymer extrudate.