3M™ Adhesion Promoter K520UV is a liquid primer used to improve the adhesion of 3M™ Acrylic Foam and Acrylic Plus Tapes.3M Adhesion Promoter K520UV is a liquid primer used to improve the adhesion of 3M acrylic foam and acrylic plus tapes to Polyolefin-based substrates such as thermoplastic olefins (TPO), polypropylene (PP), and ethylene propylene diene monomer (EPDM) rubber. A fluorescent dye has been added so that the primer coverage can be verified. Since formulations and surface energies vary for these materials, each application should be verified through testing. Apply promoter only to areas that will be fully covered with tape. The primer should be dry before applying tape. For best results, apply tape immediately after primer application or no more than one hour after primer applications. Be sure the primed surface remains free from contaminants prior to tape application.