Two-Component Polyurethane Sealant
This information reflects our best understanding of product composition in 2022.
Two-component polyurethane sealants are comprised of Part A and Part B components mixed just prior to application. As with single-component PU sealants, two-component systems rely on a reaction between polyols and isocayantes. Unlike single-...
Two-component polyurethane sealants are comprised of Part A and Part B components mixed just prior to application. As with single-component PU sealants, two-component systems rely on a reaction between polyols and isocayantes. Unlike single-component polyurethane sealants, two-component systems do not require moisture to cure and therefore cure more quickly and may be used in sealing deeper joints. The polyol portion is typically found in Part A and the isocyanates in Part B. Additional additives include fillers, plasticizers, solvents, moisture scavengers, catalysts, stabilizers, and adhesion promotors. These sealants can be used in interior or exterior joint sealing applications such as expansion and control joints, siding gaps, gaps around perimeters of doors and windows, and other wall penetrations. They are commonly paintable and meet ASTM C920 Type M, Grade NS with a typical joint movement capability of +/-50%. Some manufactuers offer an additional accelerator component (Part C) to increase the rate of cure in cold weather applications. Part C is not covered by this CP.