Typical Formulation Ingredients
Phase
Ingredient
Parts by weight
A
Ethylene vinyl acetate copolymer (Melt Index of 2-3)
A
Ethylene vinyl acetate copolymer (Melt Index of 2-3)
A
Polyethylene resin (Epolene C-15, Westlake)
A
Polyterpene resin (Wingtack 115, Cray Valley)
A
Antioxidant (Wingstay L, Omnova)
Typical Properties
Brookfield viscosity, cps at 90° C
Brookfield viscosity, cps at 175° C
Ring and ball softening point, °C
Resulting Properties
EVA copolymers having vinyl acetate content of 40% or higher have utility as PSAs. These copolymers, which also require high levels of tackifiers, were at one time the base materials for HMPSAs, but they have almost completely been displaced by the triblock copolymers. Although somewhat lower in cost than styrene block copolymers, EVA has been unable to compete successfully because of low tack and poor shear strength especially in applications requiring elevated temperature resistance.
(Source: Adhesives Formulary Handbook, NIIR Board, Asia Pacific Business Press, Inc., 2010, p. 289)