PSI-591 is a reactive polyurethane that promotes the adhesion of PSI polysulfide and polyurethane sealants to porous substrates such as concrete. It reacts with atmospheric moisture to form a hard film with outstanding water resistance and high adhesive strength to many materials.
PSI-591should be used when a single-component primer is needed on porous materials such as when firming up friable or sandy concrete, or on brick and stone. It also provides water resistance when PSI urethane sealants are used on non-porous materials such as metals and plastics; however, PSI-590 is the first choice for those materials. For PSI urethane sealants in joints subjected to continuous water immersion, PSI Primer 67 should be used.