Resins (film formers or binders) are the most important components of coatings since many important properties of dry films, such as hardness, adhesion, chemical and solvent resistance and durability, are primarily dependent on the nature of the resins used. After application of coatings, resins form useful films by a variety of physical and/or chemical mechanisms that convert liquid films into a dry coating. The term binder is frequently used to refer to a resin since one of its roles is to “bind” pigment particles in the dry film. Resins used for paints and coatings are polymeric materials with film forming capabilities. Resins control most of the physical, chemical and mechanical properties of the coatings. It is important to note that while there are hundreds of types of polymers commercially available, only a few are useful as binders for coatings because of the specific requirements for the successful use of binders in coatings.
More details on these requirements and different types of binders are covered in Chapter 2.