Since the introduction of waterborne sealants in the 1960s, acrylic emulsion formulations have matured commercially as intermediate performance architectural sealants. Some of the earlier problems that had been associated with the earlier waterborne sealants such as aging, cracking, and freeze-thaw stability have been resolved with acrylic products. Also, newer acrylic sealant formulations have been developed for demanding applications where significant joint movement is expected.
The main difference in the newer generation of acrylic sealants is that they are highly plasticized. The older generation had about 20-25% plasticizer; whereas, the newer products have a plasticizer content that is close to 33%. This high plasticizer loading results in very flexible sealants with a movement capability as high as +/- 25% and the ability to meet most of the performance standards in the industry.
This article will first review the many classifications of sealants that are commonly employed in the building and construction industry.