Closely connected to dip coating, plastic dip molding is used widely in the consumer, medical, electronic and packaging industries. Common products formed by plastic dip molders include plastic caps and plastic plugs, latex gloves, handles and grips for tools, appliances and sports equipment etc. The process is almost entirely automated which ensures labor costs are kept low.
First, a polymer coating is heated until it reaches a liquid state. In the case of the material plastisol, it is liquid at room temperature and therefore does not require additional heating before being used in the dip molding process. Molds or mandrels of primed aluminum or steel are formed in the negative of the desired part or component, and are then preheated and lowered into the molten polymer where the surface and the plastic adhere to each other. Some dip molded parts may then be further heat treated in order to fully bond the polymer to the surface of the metal, or to achieve a desired texture on the surface of the part.
In addition to providing a colorful, attractive finish to products, plastic coatings can improve corrosion resistance, scratch and wear protection and provide a smooth grip for better handling. Plastic dip molding results in precise parts with close tolerances of wall thickness. Oven temperature, rate of dip and length of dip, as well as the speed at which an object is removed from the polymer all affect the configurations of the part. For example, double walls can be manufactured by dipping a mold into the plastisol or polymer twice and allowing the layers to form separately.
Hardness and finish texture can also be adjusted according to the intended use of the product and the most suitable design. Products for use outdoors such as wire fencing, sports and recreational equipment, tools etc. can all benefit from the protective qualities of polymer coatings. Specialized coatings such as UV coating can be used for products such as eyeglasses, automotive windows and other outdoor products to prevent against sun damage.