CRL White Grainy Polyurethane Construction Sealant Cartridge

• One-part, grainy textured finish with primerless adhesion on most construction surfaces, including KYNAR® coated metals
• AAMA approved
• VOC compliant — only 9 g/L
• UV resistant / non-yellowing

CRL M66 (SKU: M660FW) is a one-part, moisture-curing, gun-grade modified polyurethane construction sealant formulated for moving joints. It requires no primer on most common construction substrates and delivers durable, flexible performance for perimeter joints, storefronts, curtain walls, and glazing applications.

Basic Uses
CRL M66 modified polyurethane construction sealant outperforms traditional solvent polyurethanes for sealing moving joints in concrete, masonry, metal, and common perimeter joint applications. Ideal for joints between framing (door and window) and building structure in storefront and curtain wall systems to provide a watertight installation. Provides excellent adhesion to fluoropolymer metal coatings such as KYNAR®, Duranar®, and Duranar® Sunstorm™, plus standard metals, aluminum, steel, galvanized steel, plastics, vinyl, glass, wood, concrete, brass, and other common substrates.

Compatible with insulating glass sealants when used as a toe or heel bead. Suitable for exterior and interior use. Service temperature after full cure: -75°F to 300°F (-59°C to 149°C). Paintable after two hours with water-based paints.

The light grainy texture helps match textured substrates like stucco and masonry and conceals tooling marks on smooth metal storefront joints. Also suitable for manufacturing uses such as travel trailers, mobile homes, and galvanized HVAC ductwork assembly.

Features
- Exceptional adhesion to KYNAR® coated metals and other fluoropolymer finishes.
- VOC compliant — only 9 g/L (chemically curing < 3%).
- Eco-friendly: solvent-free, isocyanate-free; qualifies for LEED EQ indoor air quality credit.
- Low-temperature gunning and application above 0°F (-18°C).
- Permanently flexible — resists hardening with age and remains flexible at low temperatures.
- Fast cure: skins over in ~30 minutes; cures at ~1/8" (3 mm) per day.
- Tooling time: ~20–40 minutes depending on temperature and humidity.
- Paintable with water-based paints in about two hours.
- UV resistant — non-yellowing for long-term exterior performance.

Technical Data
CRL M66 conforms to and passes Federal Specification TT-S-00230C Type II Class A and ASTM C920-98 Type S Grade NS Class 25 (Use NT, M, T, A, G, and O). Also tested to ASTM C510, C639, C661, C679, C717, C719, C793, C794, C1183, C1193, C1246, D412, D624, and G155. CAN/CGSB-19,13-M87 Type MCG-2-25-A-N QPL #81026. AAMA 808.3-92 Exterior