Pressure sensitive adhesive material and method of preparation

摘要

The present invention provides a process for making a water vapor permeable pressure sensitive adhesive material which comprises forming on a surface which is poorly wettable (or non-wettable) by water, a continuous coating of an aqueous emulsion based pressure sensitive adhesive having dispersed therein a water immiscible organic liquid which is more volatile than water and which does not break the emulsion; leaving the coating at room temperature until pores develop and reach a size such that the material when dried will have a water vapor permeability of from 2000 to 10,000 units as hereinafter defined; drying the coating at a higher temperature and transferring the adhesive mass to a water vapor permeable backing material. The pressure sensitive adhesive material finds use in the medical and surgical fields and especially in first-aid dressings and tapes.