ADVANCEMENTS IN SOLVENTLESS TECHNOLOGY FOR SILICONE PSAs

Silicone Pressure Sensitive Adhesives (PSAs) have been used for many years in areas where typical organic PSAs have failed. One of the most important uses is in applications where large temperature extremes occur. A wide variety of silicone PSAs are available on the market today and in all cases these materials are offered at 50-60 % solids in an organic carrier solvent. While many organic PSAs have found alternative delivery systems (emulsion, hotmelt, etc.), industrial silicone PSAs have been slow to evolve with the times. Attempts have been made in the past to make solventless versions of an industrial silicone PSA without much commercial success. The PSA would have the tack and adhesion performance that was typical of a silicone PSA, but the high temperature shear performance was lacking. Recently, there have been advancements in silicone-based raw materials that have opened up the ability to formulate solventless silicone PSAs that have the tack, adhesion and high temperature shear performance of common solvent-based silicone PSAs. This paper will discuss the performance of past solventless attempts, current solvent-based products and a novel solventless silicone PSA (patent pending) using 180 degree peel, Polyken probe tack, Texture Analyzer, High Temperature Shear testing and Rheology testing procedures