Introduction
Adhesive bonding, today, is employed in a variety of materials. Synthetic adhesives have been an integral part in furniture production, since mid 1900. Mostly, the adhesives are composed of polyurethanes (PUR). PURs are considered to belong to a range of chemicals sharing similar chemistry. These are polymers, composed of units of organic chains joined by urethane or carbamate links. Most PURs are thermosetting polymers and are resistant to high temperatures, hence do not melt. Polyurethane polymers are formed by the reaction of isocyanate and a polyol. Both the isocyanates and polyols used contain two or more functional groups per molecule, generally.