A definition of “bio-based” is a good starting point for this discussion. The U.S. Department of Agriculture (USDA) defines bio-based products as those derived from plants and other renewable agricultural, marine, and forestry materials. Standardized tests have been developed (ASTM D 6866) to quantify the bio-based content of a product or a raw material. The USDA provides a Certified Biobased Product label to provide information to consumers about the bio-based content of a product.
Bio-based low-molecular-weight raw materials (e.g., polyisocyanates and polyols), as well as high-molecular-weight polymers, can be used to formulate a finished adhesive. The bio-based adhesives can be supplied as one- or two-component 100% solids formulations or in solvents or waterborne dispersions. These are the same classes of final products that can be manufactured from petrochemical-based feedstocks.