7711 (Hempel 259JB) is a plasticizer free, single-component, water-based acrylic primer. Primer is applied over smooth asphalt roof surfaces to improve adhesion of silicone roof coatings. The Bleed Block Primer acts as a barrier between the asphalt and the silicone roof coating to prevent yellowing of the silicone coating due to chemicals bleeding out from the asphalt.