Below is a list of Plastic Coating manufacturers from St. Charles, Illinois. Plastic coating is the process of using a molten polymer or plastic to provide a protective covering for manufactured components. Although there are other methods of plastic coating, dip molding is the most common method, and is more efficient and cost-effective than others. The most common material used in dip coating is plastisol, a polymer which is liquid at room temperature and solidifies permanently when heated.