A mesh reinforced pressure-sensitive adhesive for a linerless label design†

Abstract

A concept for an on-demand linerless pressure sensitive adhesive (PSA) label is shown. Containment of a PSA has been achieved by entrapment within a scaffolding 3D hard mesh structure. The label sticks upon instant application of heat and pressure, which softens and deforms the mesh allowing for PSA release. The design eliminates the need for a release liner and release coating in labels offering a more sustainable product. Herein, the mesh-reinforced PSA system was made by film formation of a binary polymer latex mixture consisting of ‘hard’ (high glass transition temperature, T_g,hard) polystyrene particles and a ‘soft’ (low glass transition temperature T_g,soft) poly(n-butyl acrylate)-based PSA latex of similar particle diameter, onto a model polyethylene terephthalate (PET) facestock. The system was annealed above T_g,hard to fuse the polystyrene colloids, creating a 3D interconnected open cellular network. The porous scaffold was shown by scanning electron microscopy, X-ray computed tomography, and confocal microscopy. The linerless PSA label is in a dormant, ‘non-stick’ state at room temperature, showing excellent blocking resistance under storage conditions. Adhesion is activated on demand with heat (T > T_g,hard) and light pressure. The adhesive behavior of the linerless PSA labels was probed using peel, shear strength and tack, its performance being promising.