Some of thermoplastic rubbers (TPR) like polystyrene-block-polyisoprene copolymers (SIS) are to be reconfigurated to make us formulate, with using less solvent or no solvent, much softer and tackier pressure sensitive adhesives (PSA). None of currently available SIS copolymers is able to produce tacky enough PSA. Relatively softer ones among available SIS copolymers, which are best fit to produce large volume commodity products like carton box sealing tapes, are yet too rigid and too elastic to produce any tackier PSA. In order to get them, styrene contents in SIS copolymers should be minimized while isoprene contents are to be maximized. Furthermore, numbers of SI copolymers co-existed with SIS copolymers should be increased while those of SIS copolymers should be decreased to increase as many freely movable polyisoprene chains as possible. Saturated TPR like polystyrene-block-polyethylenebutylene copolymers (SEBS) should also be reconfigurated as the same way as SIS copolymers would be done.
Redesigned TPR would not have to be pelletized. Several PSA which are based on natural rubbers, TPR, saturated TPR, acrylic copolymers and emulsified polymers are also briefly reviewed.