The concept of microencapsulation has interested coatings, adhesive, and sealant (CAS) formulators for some time. Most applications that will come immediately to the formulator’s mind involve the rapid, triggered (instantaneous) release of encapsulated ingredients. However, there is another release mechanism that is less well understood, but opens possible opportunities for microencapsulation in the CAS industries even further.
This is a sustained release mechanism, where instead of a rapid release, release occurs over an extended period of time. Sustained release, for example, can maximize the effectiveness of an additive by delivering it slowly over time. Sustained release microencapsulation technology has been developed and commercialized primarily for drug delivery (pharmaceuticals), fragrances (textiles), and pesticides (agricultural chemicals). However, this technology appears to be ready to move into CAS products.
This article will focus primarily on the sustained release of microencapsulated components within coatings, adhesives, and sealants. The basics of this technology will be described as well as some interesting current applications. A few innovative possibilities will also be suggested which, with development, could provide valuable new or improved products.