Abstract: An insulated glass unit comprises two sheets of glass separated by an aluminum spacer, a thermosetting resin sealant such as a polysulphide or polyurethane sealant or a hot melt butyl sealant being applied around the edges of the unit to seal the sheets together. The spacer is connected by corner keys made of aluminum tape. Curing or melt-bonding of the sealant is accelerated by the application of microwave energy, suitably by passing the unit through a tunnel with microwave generators on each side thereof. The unit passes through the tunnel on a conveyor held upright by pinch chains. The conveyor and pinch chains are made of a nonpolar material such as polypropylene.

Abstract: A one-part polysulfide sealant composition comprises a mercaptan-terminated liquid polysulfide, an oxidising agent to cure the catalyst a desiccant such as a molecular sieve, to keep the composition dry and thus prevent premature activation of the catalyst, and a cure accelerator having an acrylate or methacrylate functionality of 2 or more, preferably an acrylated liquid polysulfide or a polyfunctional methacrylate monomer. The use of this accelerator avoids the need for toxic amounts of barium oxide desiccant and substantially shortens the tack-free time on curing.

Abstract: A process for the manufacture of a partially cured polysulphide composition is provided, the curing of which is completed upon exposure of the composition to atmospheric moisture. The process comprises mixing a prepolymer with a water activatable curing agent and subjecting the composition to a partial cure with water. The reaction is then stopped by rapid dehydration after the initial induction stage of the reaction prior to the rapid increase in the viscosity of the composition. Curing of the composition is then completed by exposing the composition to atmospheric moisture.