Correlation of pressure sensitive adhesive performance to surface chemistry upon air exposure

Abstract

A double-sided tape product was found to have unacceptable tack and peel on the solvent rubber side of the construction when tested several months after production. In the course of the investigation, using time-of-flight secondary ion mass spectrometry, the authors determined that a glycerol rosin ester tackifier used in the pressure sensitive adhesive tape formulation oxidized at the surface of the adhesive when exposed to both oxygen (air) and moisture in less than 24 h, which corresponded with decreased pressure sensitive adhesive properties. After continued exposure, the authors were also able to detect migration of the tackifier to the surface by Fourier transform infrared spectroscopy, presumably from reestablishment of the equilibrium created by oxidation of the tackifier. The observed buildup of oxidized tackifier was the key cause of performance loss of the tape product.