Pressure-sensitive adhesive blend films for low-tack applications

Polymer blend films consisting of a tacky and a nonadhesive component are promising candidates for low-tack applications. Immiscibility of both components results in a phase separation process yielding a tacky matrix with glassy objects embedded. The influence of the blending ratio of the components poly(n-butyl acrylate) (PnBA) and polystyrene (PS) is addressed. The mechanical information resulting from the tack test shows the possibility of varying the bonding strength of the PSA blend over a wide range. The macroscopic and microscopic structural characterization with optical microscopy and ultrasmall angle X-ray scattering (USAXS) shows that the blend PnBA/PS exhibits similarities to common filler systems as well as deviates regarding installed structures. Due to the large domain size on a microscopic level, only the tacky component, PnBA, defines the adhesive behavior. The nonadhesive com- ponent limits the contact area between the adhesive and the substrate.