AK-CRYL CP-9 is a polymeric vinyl-acrylic, water based weather barrier, breather type mastic coating for thermal insulations. CP-9 dries to a tough flexible film that protects thermal insulation from the ravages of weather by preventing water, rain, snow, sleet, spillage, wash water, etc., from entering into the system. It also protects from physical abrasion and expansion/contraction, and contributes chemical- and fire-resistance.