MISCIBILITY AND PSA PERFORMANCE OF ACRYLIC COPOLYMER AND TACKIFIER RESIN SYSTEMS

The influence of miscibility of an acrylic PSA and several tackifier r esin systems upon PSA performance was investigated. When the acrylic c opolymer and the resins were blended in various proportions, three typ es of mixing state were found: miscible system, partially miscible sys tem and immiscible system. In the case of miscible systems, PSA perfor mance (tack, peel strength and shear resistance) depended upon the vis coelastic properties of the PSA. In the case of completely immiscible systems, the above PSA performance depended primarily upon the viscoel astic properties of a continuous matrix phase, and the separated resin phase acted as a kind of filler. In the case of partially miscible sy stems, the PSA performance changed discontinuously at the resin concen tration where phase separation occurred. It suggests that the phase st ructure of a PSA greatly influences the PSA's performance.