Typical Formulation Ingredients
Ingredient
Parts by weight
Monofunctional aliphatic urethane acrylate oligomer (Genomer 4188/EHA, Rahn Energy Company)
Difunctional aliphatic urethane acrylate oligomer (Genomer 6043/M22, Rahn Energy Company)
Diluent, ethyl acrylate monomer (Miramer M170, Rahn Energy Company)
Photoinitiator (Genocure LTM, Rahn Energy Company)
Photoinitiator (Genocure PMP, Rahn Energy Company)
(Source: Formulation Goals of Energy Curable Pressure Sensitive Adhesives, Rahn USA Corporation, 2006.)
Typical Properties
Static shear strength @ 23°C, Hr
Static shear strength @ 80°C, Hr
Resulting Properties
The above table shows a starting formulation for a UV cured pressure sensitive adhesive that has a high degree of tack. The high tack of this formulation derives from the low functionality and Tg’s of the products included. The Genomer 4188 is monofunctional and when combined with 2-EHA it offers exceptional elastic properties which are ideal for PSA’s. The Genomer 6043/M22, an inert resin cut in a monofunctional aliphatic urethane acrylate monomer, is being utilized as a low Tg (-18ºC). In addition, the diluent component is 2-(2-Ethoxyethoxy) Ethyl Acrylate, Miramer M170, which is monofunctional and has a Tg of -53ºC. The low Tg and crosslinking combination of this PSA offers very high tack performance, but very limited cohesive characteristics, which is evident in the low shear value and negligible heat resistance.