Effects of blending and coating methods on the performance of SIS (styrene-isoprene-styrene)-based pressure-sensitive adhesives

SIS (styrene-isoprene-styrene)-based pressure sensitive adhesives (PSAs) were prepared by melt- or solution-blending. In the coating process, two methods were used: solution coating and melt coating. The performances of the PSAs were found to be different, depending on which of these two blending or coating methods was used. In this study, we investigated the relationship between the viscoelastic properties and the performances of the SIS-based PSAs using different blending and coating methods. Three methods were used: (1) melt-blending and melt-coating, (2) melt-blending and solution-coating and (3) solution-blending and solution-coating. PSAs applied using melt-blending/melt-coating (M-M) have higher peel strength and probe tack than PSAs applied using melt-blending/solution-coating (M-S) and solution blending/solution coating (S-S). However, PSAs applied using M-M blends have lower holding power and SAFT (Shear adhesion failure temperature) than PSAs applied using M-S and S-S blends. The viscoelastic properties and GPC curves of M-S blends were similar to M-M blends, while the peel strength and tack of M-S blends were similar to S-S blends. Therefore, it was concluded that the blending process had more effect on the viscoelastic properties and shear creep of PSAs than the coating process.