Bayer MaterialScience recently unveiled the new DISPERCOLL® U XP 2699 polyurethane dispersion which it says combine the environmental advantages of a water-based sealant with the superior physical properties of a polyurethane resin in a new, high-performance water-based sealant. Dr. Jay A. Johnston, senior associate scientist, Bayer MaterialScience LLC, presented his research at Adhesives & Sealants Council Spring Meeting 2009 on April 7, 2009. As opposed to low-VOC water-based sealants prepared form acrylic resins, a sealant formulated with the DISPERCOLL® U XP 2699 dispersion demonstrates physical properties similar to a reactive sealant, despite being water-based, according to Johnston's work. And, his research also shows that adjusting the filler, plasticizer and resin ratios enables further fine tuning of the physical properties of the final sealant.
According to Johnston, low-VOC water-based sealants prepared from acrylic resins have long been available in the commercial market. Though being water-based and environment friendly, these sealants usually have less desirable physical properties when compared with sealants formulated with reactive chemistries. These less desirable properties include lower tensile strength, lower tear resistance, less elasticity, poorer environmental resistance, and a tendency to shrink during cure.