For bonding – especially outdoors and on surfaces that are difficult to bond – we recommend the use of a bonding agent, like our tesa® Adhesion Promoters. Bonding agents form a layer on the surface to which the pressure-sensitive adhesive adheres particularly well.
Indeed, there are plastics and other materials to which adhesive does not stick well. Polyethylene (PE), polypropylene (PP), Teflon, rubber, and silicone are some of these. Experts speak of "very low surface energy."
The exciting thing about a primer is it increases this surface tension, which lets the tape stick to the substrate more strongly. This layer also prevents water from entering the adhesive joint and thus enables consistent outdoor bonding.