CONSIDERATION OF ADHESION TO MODIFIED CONTAINER WALLS, BY USE OF SURFACE-ENERGY AND POLARITY DATA, AND LEWIS ACID-LEWIS BASE INTERACTIONS

It is acknowledged that the labelling of pharmaceutical products is essential on legal and ethical grounds. The desirability of using high speed filling operations for large bulk liquid products, has resulted in the surface coating of bottles with lubricant films, to allow smoother movement through the filling process. In this study the adhesion to bottles which have had one of two different types of lubrication treatment is considered. Simple empirical testing demonstrates that certain combinations of bottle coat and adhesive will result in adhesive failure (loss of label), whilst others are acceptable. The interaction between the adhesive and the bottles has been modelled using theories based on surface energy data. Both the polar and dispersion view of surface energy components, and the concepts of viewing the polar contribution to surface energy as comprising of non-additive Lewis acid-Lewis base components (with particular reference to monopolar surfaces) are considered. It was found that both methods of considering surface energy data gave some indication of adhesive performance, but only the acid-base approach gave a method of correlating predicted behaviour with empirical use tests. It is probable that the acid-base approach is the more appropriate for general application.