Analysis Of Polyethylene-Based Cold End Coatings On Glass Containers With Contact Angle And Ir Spectroscopy

The aim of cold-end coating is to protect the glass surface from abrasive wear with the help of a suitably anchored film of organic material which decreases friction, by preventing direct glass to glass contacts. At present, routine controls on cold end coatings are limited to a lubricity test, i.e. determination of the slide angle. A laboratory procedure based on the determination of the contact angle with water is described in this work. It allows one to estimate the coverage with cold-end coating locally from the water repellence caused by the organic deposit. The method can be used to investigate a range of problems associated with glass wettability, indluding label adhesion, acid etching and washing residues. The contact angle correlates well with the slide angle.