Abstract: An insulated glass sealant having the best characteristics of polysulfides and polyurethanes rather than the worst is made from a polysulfide-based polyurethane which, in turn, is derived from a mixture of hydroxyl terminated polysulfides having a structure represented by the following formula: RCH2CH2OCH2OCH2CH2S[SCH2CH2OCH2OCH2CH2S]nSCH2CH2OCH2OCH2CH2R. wherein R═HO(CH2)ySS, y is from 2 to 6, and n is such that the molecular weight is from about 2500 to about 4000. The improved sealant of this invention is prepared by a one-step procedure wherein the hydroxyl terminated polysulfide of said formula is reacted with a polyisocyanate at a ratio between about 1:1 and about 1:1.2 on an equivalents basis. The hydroxyl-terminated polysulfide is made by splitting a polysulfide having a molecular weight about 30 times greater in an aqueous latex dispersion with a dithiodialkylene glycol and sodium sulfite.

Abstract: The moisture vapor transmission rates of sealants containing liquid polysulfides made from mixtures of a hexylene dihalide and a chloroethyl formal wherein the molar ratio is from about 1.5:1 to about 2.3:1 are extremely low. A preferred ratio is 0.64:0.36. The new liquid polysulfide is useful in conventional sealant formulations for insulated glass window units.

Abstract: Solid waste materials comprising oxidatively-cured, solid polysulfide sealants containing spent oxidant, fillers, plasticizers, and other formulating aids are reverted to a liquid sealant comprising mercaptan-terminated polysulfides by reducing them with a liquid mercaptan-terminated polysulfide at temperatures ranging from about 50.degree. to about 110.degree. C. Upon the addition of fresh curing agent and recuring, the reclaimed sealant has satisfactory tensile strength and elongation properties.