2020 Volume 56 Issue 12 Pages 463-471
The compatibility of blend systems of styrene-isoprene block copolymer（ SIS） and tackifier resins with different solubility parameters（ δ） was verified by AFM observation and SAXS measurement. We discussed “Viscoelastic windows”, which is the mechanical property of the pressure sensitive adhesive bulk, and its effect on the final adhesive performance. For the resins compatible with the polyisoprene（ PI） phase, C5/C9 petroleum resin, which has a slightly higher δ value than C5 petroleum resin, reduces the polystyrene（ PS） domains that acts as a physical cross linking points between SISs. So it was suggested that the cohesive strength of the system decreased, which led to an increase in tack and adhesion. On the other hand, coumarone-indene resin and α-methylstyrene resin, which are compatible with PS phases with high δ value, it suggested that there are preferentially compatible with PS phases, and some are slightly localized in the surrounding PI phases. The tack and peel strength is increased by adding coumarone indene resin with high δ value to C5 petroleum resin, but it decreases conversely when coumarone indene resin is added to C5/C9 petroleum resin. This is thought to be due to the relative decrease in the compatibility of the coumarone indene resin to the PS phases due to the decrease in the PS domains by the addition of C5/C9 petroleum resin, which led to a decrease in adhesive properties.
