CRL Bronze Grainy Polyurethane Construction Sealant Cartridge

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

SKU: M66BRZ

CRL M66 is a one-part, moisture-curing, gun-grade modified polyurethane construction sealant. Primer is not required on most common substrates. Durable and permanently flexible, M66 excels in moving joints for storefronts, curtain walls, perimeter joints, and other exterior or interior seal applications.

Why choose CRL M66?

• Exceptional adhesion to fluoropolymer metal coatings (KYNAR®, Duranar®, Duranar® Sunstorm™) and standard metals, aluminum, galvanized steel, plastics, vinyl, glass, wood, concrete, brass, and other common building substrates
• Low-VOC, solvent-free, isocyanate-free formula — qualifies for LEED® EQ credits
• Fast skin-over (≈30 minutes) and cures ~1/8" (3 mm) per day; paintable after 2 hours with water-based paints
• Service temperature after full cure: -75°F to 300°F (-59 to 149°C)
• Light grainy texture hides tooling marks and matches textured substrates like stucco and masonry

Basic uses

Formulated to outperform traditional solvent polyurethanes for sealing moving joints in concrete, masonry, metal, and perimeter applications. Ideal as a watertight seal between framing (doors and windows) and building structure in storefront and curtain wall systems. Compatible with insulating glass sealants when used as toe or heel beads. Also used in manufacturing applications such as travel trailers, mobile homes, and galvanized HVAC ductwork assembly.

Features

• VOC compliant — 9 g/L (chemically curing < 3%)
• Eco-friendly: solvent-free, isocyanate-free; qualifies for LEED
• Low-temperature gunning and application above 0°F (-18°C)
• Permanently flexible — resists hardening with age
• Tooling time: ~20–40 minutes (varies with temperature/humidity)
• UV resistant — will not yellow from sun exposure

Technical compliance

Meets Federal Specification TT-S-00230C Type II Class A; ASTM C920-98 Type S Grade NS Class 25 (Uses NT, M, T, A, G, O).