Insulating glass sealants based on polyurethanes and organically-modified nanoclays
Curable compositions are prepared using polyisocyanates, hydrophobic hydroxyl-terminated polymers (such as hydroxyl-terminated polyfarnesenes and hydroxyl-terminated polydienes) and organically-modified nanoclays, optionally in combination with chain extenders and/or urethane catalysts. When cured, the compositions yield polyurethane-based sealants useful in insulating glass units which have improved (lowered) moisture vapor transmission rate values as a consequence of the inclusion of the organically-modified nanoclays.
1. A curable composition useful for producing an insulating glass sealant, wherein the curable composition comprises at least one organically-modified nanoclay, at least one hydroxyl-terminated polyfarnesene, and at least one polyisocyanate.
2. The curable composition of claim 1 , wherein the at least one hydroxyl-terminated polyfarnesene has a number average molecular weight of from about 1000 to about 20,000 g/mole.
3. The curable composition of claim 1 , wherein the at least one hydroxyl-terminated polyfarnesene has an average hydroxyl functionality of at least about 1.8.
4. The curable composition of claim 1 , wherein the at least one hydroxyl-terminated polyfarnesene comprises at least one hydroxyl-terminated polyfarnesene which is a hydroxyl-terminated polyfarnesene homopolymer.
5. The curable composition of claim 1 , wherein the at least one hydroxyl-terminated polyfarnesene comprises at least one hydroxyl-terminated polyfarnesene which is a hydroxyl-terminated polyfarnesene copolymer comprised of copolymerized units of farnesene and at least one diene co-monomer.
6. The curable composition of claim 1 , wherein the curable composition is additionally comprised of at least one chain extender.
7. The curable composition of claim 6 , wherein the at least one chain extender comprises at least one polyamine chain extender or polyol chain extender.
8. The curable composition of claim 1 , wherein the curable composition is comprised of from about 1 to about 12 weight % organically-modified nanoclay.
9. The curable composition of claim 1 , wherein the at least one organically-modified nanoclay comprises at least one organically-modified montmorillonite nanoclay.
10. The curable composition of claim 1 , wherein the at least one organically-modified nanoclay comprises at least one organically-modified nanoclay that is modified with quaternary alkylammonium.
11. A curable composition useful for producing an insulating glass sealant, wherein the curable composition comprises at least one organically-modified nanoclay, at least one hydroxyl-terminated polymer comprised of at least one hydroxyl-terminated polyfarnesene and at least one hydroxyl-terminated polybutadiene, and at least one polyisocyanate.
12. A curable composition useful for producing an insulating glass sealant, wherein the curable composition comprises at least one organically-modified nanoclay, at least one hydroxyl-terminated polymer selected from the group consisting of hydroxyl-terminated polyfarnesenes and hydroxyl-terminated polydienes, and at least one polyisocyanate, wherein the curable composition is comprised of from 5% to 100% by weight hydroxyl-terminated polyfarnesene and 0 to 95% by weight hydroxyl-terminated polybutadiene based on the total weight of hydroxyl-terminated polymer.
13. A curable composition useful for producing an insulating glass sealant, wherein the curable composition comprises at least one organically-modified nanoclay, at least one hydroxyl-terminated polymer selected from the group consisting of hydroxyl-terminated polyfarnesenes and hydroxyl-terminated polydienes, at least one polyisocyanate, and at least one urethane catalyst.
14. The curable composition of claim 13 , wherein the at least one organically-modified nanoclay comprises at least one organically-modified montmorillonite nanoclay.
15. The curable composition of claim 13 , wherein the curable composition is additionally comprised of at least one chain extender.
16. The curable composition of claim 13 , wherein the at least one hydroxyl-terminated polymer has an average hydroxyl functionality of at least about 1.8.
17. A method of making a sealant, comprising curing the curable composition of claim 1 .
18. A sealant, comprising at least one organically-modified nanoclay and a polyurethane produced by reaction of an admixture comprising at least one hydroxyl-terminated polyfarnesene and at least one polyisocyanate.
19. An insulated glass unit comprising at least 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 comprising a sealant in accordance with claim 18 .