Stephen Edward Webb

US Patent:

6423810, Jul 23, 2002

Filed:

Feb 5, 2001

Appl. No.:

09/777209

Inventors:

Jian-ping Huang - Apex NC
Stephen R. Webb - Clayton NC
Miriam H. Zietlow - Apex NC

Assignee:

Lord Corporation - Cary NC

International Classification:

C08G 1848

US Classification:

528 77, 528 76, 528 75, 528905, 528 80, 528 60, 525131

Abstract:

Disclosed is a two-part polyurethane structural adhesive and method of bonding structural components, that exhibits at least 25 minutes of open time at 32Â C. in large beads and cures to high strength under ambient conditions. The adhesive composition in one part is an isocyanate or isocyanate prepolymer and in a second part is a polyol mixture (I) or (II), wherein 75% to 100% by weight of the polyol mixture (I) or (II) are polyols having secondary hydroxyl functionality and the polyol mixture (I) or (II) contains a long chain secondary polyol defined hereinbelow. The polyol mixture in one embodiment is substantially absent short chain polyols having functionality of 2, and includes an amount from 30% to 80 % by weight on total polyol weight in (I) of long chain secondary polyol of molecular weight from 2000 to 12000 and from 20% to 70% by weight on total weight of the polyol mixture and of a short chain secondary polyol with functionality greater than 2 and a molecular weight of from 90 to 800. In another embodiment, 5% to 80% of a long chain secondary polyol of molecular weight of from 2000 to 12000 is present together with 5% to 70% of a short chain secondary polyol having a functionality of greater than 2, and 5% to 70% of a short chain secondary polyol having a functionality of 2 and a molecular weight of from 90-800.