Over the last decade, there has been a considerable transformation in the solvent-borne industrial coatings market. Major developments have taken place in water based coatings technology, which has now expanded from the consumer house paint market into industrial sectors. Increasingly stringent VOC regulations have led to the development of a more viable water based alternative to solvent borne technology. However, some limitations still exist, particularly with the key characteristics of chemical and abrasion resistance in coating performance.

 

Alongside the advances in water based technology, has been the development of high solids coatings. These are usually formulated with lower molecular weight components to achieve the lowest possible viscosity with the minimum use of solvent. However, there is a limit to molecular weight reduction, as this can lead to problems associated with loss of coating performance.

 

An example of a market that has seen the trends as described above is 2-pack polyurethane coatings. Typically, these systems are comprised of an acrylic (or acrylic and polyester) polyol and an HDI-based polyisocyanate. These form polyurethanes that have unique performance properties including excellent chemical resistance and weather exposure as well as good abrasion resistance. One possible solution to maintaining the coating benefits of solvented systems, whilst reducing the VOC, is to incorporate a reactive diluent.