Sealant

A polymer family with a backbone of alternating silicon and oxygen atoms, giving outstanding resistance to weathering, UV and temperature extremes while remaining flexible. Silicones are used as sealants, gaskets, mould-making rubbers and liquid-applied roof coatings, and most sealant grades cure at room temperature with atmospheric moisture.

An adhesive and sealant chemistry based on polymer chains terminated with silane groups that crosslink with atmospheric moisture, combining the flexibility and weather resistance of silicones with the paintability and cleaner handling of polyurethanes, and containing no isocyanates. Widely used for elastic bonding and sealing in construction, marine deck fitting and vehicle assembly.

A broad polymer family formed by reacting isocyanates with polyols, producing everything from soft foams and elastomers to rigid plastics, adhesives, sealants and coatings. In construction and roofing it appears as insulation foam, liquid-applied waterproofing membranes and flexible adhesives, and many one-part grades cure with ambient moisture.

A curing mechanism in which a one-part adhesive, sealant or coating reacts with atmospheric humidity, hardening from the exposed surface inwards. One-part polyurethanes, silicones and silane-modified polymers cure this way; cure through thick sections is slow and depends on humidity and temperature.