CRL Tan Smooth Polyurethane Construction Sealant Cartridge - Exterior

• One-part smooth finish formula 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: M64T) is a one-part, moisture-curing, gun-grade modified polyurethane construction sealant. It typically requires no primer on most common construction substrates and provides durable, flexible performance for moving joints.


Basic Uses
CRL M64 modified polyurethane construction sealant is formulated to replace traditional solvent polyurethanes for sealing moving joints in concrete, masonry, metal, and perimeter joint applications. Ideal for joints between framing (door and window) and the building structure in storefronts and curtain walls, it secures a watertight installation and offers excellent adhesion to fluoropolymer paint coatings (KYNAR®, Duranar®, Duranar® Sunstorm™), 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. Designed for exterior and interior use, it withstands service temperatures after full cure from -75°F to 300°F (-59 to 149°C) and is paintable after only two hours with water-based paints.

Also suitable for manufacturing uses such as travel trailers, mobile homes, and assembly of galvanized HVAC ductwork.

FEATURES
Exceptional adhesion to KYNAR® coated metals.
VOC compliant — only 9 g/L (chemically curing < 3%).
Eco-friendly: solvent-free, isocyanate-free, qualifies for LEED® EQ credit (Indoor Environmental Quality).
Low-temperature gunning and application above 0°F (-18°C).
Service temperature: -75°F to 300°F (-59°C to 149°C).
Permanently flexible — resists hardening with age and remains flexible at low temperatures.
Fast cure — skins over in ~30 minutes; cures ~1/8" (3 mm) per day.
Tooling time: approximately 20–40 minutes depending on temperature and humidity.
Paintable in 2 hours with water-based paints.
UV resistant — will not yellow from sun exposure.

Technical Data
CRL M64 conforms to and passes Federal Specification TT-S-00230C, Type II, Class A, and ASTM C920-98, Type S, Grade NS,