Formulating a UV-Cure Pressure Sensitive Adhesive for PVC Foam Tapes and Converting an Oven-dry Water-Borne Material Using an LED Lamp Cure System
Brooke Shell, Novagard Solutions
Abstract: Most water-borne pressure sensitive adhesives (PSA’s) perform poorly on flexible PVC foam tapes. Plasticizers from the polyvinyl chloride (PVC) migrate into the PSA which softens the resin and reduces the overall adhesive strength. This lack of plasticizer migration resistance impacts the shelf stability of the foam tapes and limits the potential applications for these products. Solvent based PSA’s generally perform better; however, the use of solvents is often problematic and in many instances even prohibited. 100% solids, UV-cure materials may often be formulated with properties and performance similar to solvent-based compounds. Formulating the product in-house provides the opportunity to build the plasticizer resistance into the resin, monomer and tackifier combination. Proper raw material selection is essential to produce superior performance. Original formulations using a traditional mercury-vapor lamp system performed well but the excess heat scorched the foam surface. The relatively low Tg of the PVC necessitates the use of an LED curing lamp. This article describes the laboratory experiments conducted to develop the adhesive and evaluate performance. Additionally it follows the scale-up and then the full-scale implementation of the entire process on the main production line. Documenting the challenges and victories associated with each step of the execution.