Polysulfide-based polyurethane sealant for insulating glass

• US 6,322,650 B1
• Filed: 04/15/1999
• Issued: 11/27/2001
• Est. Priority Date: 04/15/1999
• Status: Expired due to Fees

• Current Assignee: Morton International Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Gilmore, John R., Hobbs, Steven J., Potts, Keith B.
• Primary Examiner(s): Gallagher, John J.
• Application Number:
  US09/292,636
• Time in Patent Office: 957 Days
• Field of Search: 428/419, 156/107, 156/331.4, 528/85, 528/76
• US Class Current: 156/107
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/307 Atmospheric humidity
• CPC Class Codes: C08G 18/64 Macromolecular compounds not provided for by groups C08G18/42 - C08G18/63
• CPC Class Codes: C08G 18/7664 containing alkylene polyphenyl groups
• CPC Class Codes: Y10T 428/31533 Of polythioether

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.

Claims

1. A method for sealing an insulated glass window which comprises filling a U-shaped channel around the perimeter of the window and between two panes of glass with a mixture of a hydroxyl terminated polysulfide having the formula:

2. The method of claim 1 wherein the polyisocyanate is a diisocyanate.

3. The method of claim 1 wherein the molecular weight is from about 2500 to about 3500.

4. The method of claim 1 wherein the NCO/OH ratio is from about 1:

1 to about 1.15;

1.

5. An insulated glass sealant comprising a polysulfide-based polyurethane prepared by reacting a hydroxyl terminated polysulfide having the formula:

6. The sealant of claim 5 wherein the polyisocyanate is a diisocyanate.

7. The sealant of claim 5 wherein n=14-20.

8. The sealant of claim 5 wherein the NCO/OH ratio is from about 1:

1 to about 1.15;

1.

9. The sealant of claim 5 characterized further by the presence of a plasticizer and a glass adhesion promoting silane.

10. An isocyanate-terminated polysulfide having the formula: