Accelerate cure of moisture curable polyurethane adhesive compositions useful for bonding glass

Abstract

The adhesive system of the invention is especially useful in bonding replacement windows into vehicles. They allow for sufficient working time while still realizing a fast drive away time. The adhesive system is comprised of a moisture curable adhesive and a cure accelerator that may be applied using a simple single caulk gun and may be applied at ambient temperatures such as −10° C. and about 45° C. The cure accelerator is comprised of a polyol having a backbone that has at least one amine in the backbone. The moisture curable adhesive typically is comprised of an isocyanate terminated prepolymer.

Description

FIELD OF INVENTION[0001]The invention relates to moisture curable adhesive compositions. In particular, the invention relates to moisture curable isocyanate terminated prepolymer adhesive compositions coupled with a separate cure accelerator useful to bond glass into vehicles and buildings.BACKGROUND OF INVENTION[0002]One-part moisture curing adhesive compositions have been used to bond windows into buildings and vehicles. Examples of adhesives useful for these applications are described in U.S. Pat. Nos. 4,374,237; 4,687,533; 4,780,520; 5,063,269; 5,623,044; 5,603,798; 5,922,809; 6,015,475; 6,512,033; 6,657,035; 6,709,539; 7,101, 950; 7,226,523; 7,361,292; 8,236,891 and CA 2,564,992. In automobile factories windows are installed using robots and computer controlled processing which facilitates the use of a variety of high performance adhesives, for instance, nonconductive adhesives and high modulus adhesives. The speed of cure is not a significant issue because new vehicles are not...

AI Technical Summary

Benefits of technology

The patent text describes a new adhesive composition that can be used to bond replacement windows into vehicles. The adhesive is a moisture curable isocyanate terminated prepolymer that can be cured quickly and consistently under a wide range of ambient conditions. The adhesive has a working time of 5, 8, or 10 minutes and can bond parts together within 60 minutes. The adhesive system also offers a suitable decking force for placement of the windshield and can perform consistently even at extreme ambient conditions.

Problems solved by technology

Even though these adhesives have built up enough integrity to be driven away in a short time, they still have required much longer times to fully cure and inconsistently cured depending on the ambient conditions such as temperature and relative humidity.

These tend to suffer, however, from complex delivery systems, to keep the two parts separate as well as requiring sufficient mixing when dispensing to realize a uniform product.

Likewise, two-part adhesive compositions tend to react quickly and may form skins resulting in insufficient working time to allow proper positioning of the replacement window under certain conditions (higher temperatures and higher relative humidity).

Thus, even though a two-part composition may allow automobiles with replacement windows to be driven within 30 minutes of bonding the window into the automobile, they have not in general allowed any quicker drive away times and care must be taken to ensure a uniform adhesive bead.

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