CRL Limestone-Textured Polyurethane Masonry Sealant Cartridge

• One-part, grainy textured finish 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 M66 (SKU: M66L) is a one-part, moisture-curing, gun-grade modified polyurethane construction sealant formulated for durable, flexible performance in moving joints. It typically requires no primer on common construction substrates and provides long-term adhesion to fluoropolymer metal coatings such as KYNAR®, Duranar®, and Duranar® Sunstorm™.

Basic Uses
CRL M66 is designed for sealing moving joints in concrete, masonry, metal, and perimeter joints around doors and windows in storefront and curtain wall systems. Ideal for waterproofing and durable perimeter sealing, it adheres well to metal, aluminum, steel, galvanized steel, plastics, vinyl, glass, wood, concrete, brass, and other common building substrates. Compatible with insulating glass sealants when used as a toe or heel bead. Suitable for both exterior and interior applications.

With a service temperature range after full cure of -75°F to 300°F (-59°C to 149°C), CRL M66 remains permanently flexible and resists hardening with age. It is paintable after only two hours with water-based paints and cures quickly (skins over in ~30 minutes; cures ~1/8" (3 mm) per day). The light grainy texture blends with stucco, masonry, and smooth metal profiles to hide tooling marks. Also used in manufacturing applications 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%).
- 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 yellowing and UV degradation.
- Fast cure: skins over in ~30 minutes; tooling time 20–40 minutes depending on conditions.
- Paintable with water-based paints after approximately two hours.

Technical Data
CRL M66 conforms to Federal Specification TT-S-00230C Type II Class A and ASTM C920 (Type S, Grade NS, Class 25, Uses NT, M, T, A, G, O). Also meets numerous ASTM standards and CAN/CGSB-19.13-M87 (QPL #81026), AAMA 808.3-92 exterior perimeter, and AAMA 802.3-