Cashew nutshell liquid (CNSL), a bio-renewable resource found in the honeycomb structure of the cashew nutshell, is considered a byproduct of the cashew industry. Therefore, CNSL is a non-food chain product that would otherwise be disposed of. Cashew trees can grow abundantly in tropical conditions.

One of the most commercially useful chemicals from CNSL is cardanol, a pentadecadienyl phenol with an aliphatic side chain that usually consists of a mixture of one, two, and three double bonds in a linear chain. This natural phenolic compound has interesting chemical structural features that enable a variety of chemical modifications to create bio-based monomers and polymers. Phenalkamine is one of most successful chemicals used in cashew nutshell liquid, along with phenalkamide, exhibiting good reactivity for fast and low-temperature cure and strong adhesion even to damp or poorly prepared surfaces. In addition, its long aliphatic side chain delivers excellent water resistance, corrosion protection and chemical resistance.