CRL Bronze Smooth Polyurethane Construction Sealant Cartridge

• One-part smooth finish modified polyurethane construction sealant with primerless adhesion on most common construction surfaces, including KYNAR® coated metals
• AAMA approved
• VOC compliant – only 9 g/L
• UV-resistant, non-yellowing

CRL M64 (SKU: M64BRZ) is a one-part, moisture-curing, gun-grade modified polyurethane sealant formulated for sealing moving joints in commercial and residential construction. It offers durable, permanently flexible performance for perimeter joints, storefronts, curtain walls, glazing toe/heel beads, and general construction joints.

Basic Uses
CRL M64 Modified Polyurethane Construction Sealant outperforms traditional solvent polyurethanes for sealing moving joints in concrete, masonry, metal, and typical perimeter joint applications. Ideal for joints between framing (doors and windows) and building structure in storefront and curtain wall systems to create a watertight installation. This advanced polymer provides excellent adhesion to fluoropolymer paint coatings on metal surfaces—including KYNAR®, Duranar®, and Duranar® Sunstorm™—and bonds well to standard metal, aluminum, steel, galvanized steel, plastics, vinyl, glass, wood, concrete, brass, and other common building substrates.

CRL M64 is compatible with insulating glass sealants when used as a toe or heel bead. Suitable for interior and exterior use. Full-cure service temperatures range from -75°F to 300°F (-59°C to 149°C). Paintable with water-based paints after approximately two hours.

Also used in manufacturing applications such as travel trailers, mobile homes, and assembly of galvanized HVAC ductwork.

FEATURES
- Exceptional primerless adhesion to KYNAR® coated metals and common construction substrates.
- Low-VOC, solvent-free, isocyanate-free (VOC compliant – 9 g/L; chemically curing < 3%).
- Qualifies for LEED® Indoor Environmental Quality credits (EQ).
- Low-temperature gunning and application down to 0°F (-18°C).
- Permanently flexible; remains flexible in low temperatures and resists hardening with age.
- Fast cure: skins in ~30 minutes; cures ~1/8" (3 mm) per day.
- Tooling time: ~20–40 minutes depending on temperature and humidity.
- Paintable with water-based paints after ~2 hours.
- UV resistant and non-yellowing for long-term exterior performance.

Technical Data — CRL M64 conforms to and passes:
Federal Specification TT-S-00230C, Type II, Class A.
ASTM C920-98, Type S, Grade NS, Class 25, Use NT, M, T, A, G, and O.
ASTM