The 2006 Additives Guide is a brief description of the various additives and some generic examples to give a basic understanding of where additives (as opposed to polymers, pigments/extenders and solvents) fit into the coatings arena.
The function of additives is almost always very specific in nature. Their function can vary from being independent of the other ingredients in the "can" and on their performance in the final coating, to those whose function is critical to performance and on which performance of the final coating is vitally dependent. Still other additives may be important to the manufacturing process and important to a coating's performance - that is, they have a dual purpose. For example, a defoamer may be a production aid that is critical to the manufacturing process, but may or may not contribute anything to the application or final coating properties. A flow and leveling aid probably contributes nothing to the manufacturing process and may even have a deleterious effect, but it is necessary to obtain a smooth, glossy final coating that will have the eye appeal necessary for a decorative coating. A bactericide may be important in preventing bacterial contamination of production equipment and stored paint, but will do nothing to protect the cured paint film.