Patent ID: 8257805

Claim:
An insulated glass unit comprising two spaced-apart sheets of glass in spaced relationship to each other, a low thermal conductivity insulating gas or mixture of gases therebetween and a gas sealant element including a cured sealant composition having a permeability to gas of less than 900 banners, the cured sealant composition resulting from the curing of a curable sealant composition comprising: a) at least one silanol-terminated diorganopolysiloxane; b) at least one crosslinker for the silanol-terminated diorganopolysiloxane(s) having the formula: (R 14 O)(R 15 O)(R 16 O)(R 17 O)Si where R 14 , R 15 , R 16 and R 17 are chosen independently from monovalent C 1 to C 60 hydrocarbon radicals; c) at least one catalyst for a crosslinking reaction wherein the silanol terminated diorganopolysiloxane is crosslinked to provide a crosslinked diorganopolvsiloxane; d) at least 15 percent up to 50 percent by weight, based on the total composition weight, of at least one organic nanoclay including a diorganopolysiloxane intercalant, where the nanoclay portion of organic nanoclay (d) is selected from the group consisting of montmorillonite, sodium montmorillonite, calcium montmorillonite, magnesium montmorillonite, nontronite, beidellite, volkonskoite, laponite, hectorite, saponite, sauconite, magadite, kenyaite, sobockite, svindordite, stevensite, vermiculite, halloysite, aluminate oxides, hydrotalcite, illite, rectorite, tarosovite, ledikite, kaolinite and, mixtures thereof, the nanoclay portion being treated by at least one of a tertiary alkylammonium compound, tertiary amine compound R 3 R 4 R 5 N and/or quaternary ammonium compound R 6 R 7 R 8 R 9 N + X − wherein R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , and R 9 each independently is an alkyl, alkenyl or alkoxy silane group of up to 60 carbon atoms and X − is an anion to provide the organic portion of the organic nanoclay (d); and, e) at least one solid polymer having a permeability to gas that is less than the permeability of the crosslinked diorganopolysiloxane(s), wherein said insulated glass unit further includes a spacer member disposed between the two sheets of glass, the spacer member having two lateral sides and an end surface, and wherein the low thermal conductivity gas includes one or more of air, carbon dioxide, sulfur hexafluoride, nitrogen, argon, krypton or xenon, and wherein the cured sealant composition includes a nonionic surfactant selected from the group consisting of polyethylene glycol, polypropylene glycol, ethoxylated castor oil, oleic acid ethoxylate, alkylphenol ethoxylates, copolymers of ethylene oxide and propylene oxide and copolymers of silicones and polyethers, copolymers of silicones and copolymers of ethylene oxide and propylene oxide and mixtures thereof.