Dip coating is a straightforward and relatively cost-effective method of coating objects and is a three-step process. It begins with the immersion of an object or manufactured component into a vat of molten plastic, in this case PVC. A primer such as phosphate or chromate may be applied to the surface of the component to increase the adhesion of PVC to the surface.
Depending on the desired thickness of the PVC coating, the object is then removed slowly and allowed to harden. If an object is removed from the molten PVC too quickly, there may be irregularities on the surface of the object or in the coating thickness. Further heat treatment may be added to the process to complete the fusion of PVC to the surface. Due to the automatic nature of dip molding machines, the turnaround rates are high, as the time for one object to be successfully coated is short.
There is also minimal material wastage as a result of this process as the only molten plastic that is used adheres to the object itself. The remaining material is still in the vat for the next dipping process, making the process of dip coating, or plastic coating, a responsible manufacturing choice.
The reasons for using PVC coatings can be both protective and decorative, although its protective qualities are typically more important. Dip coating is not restricted by shape for its coating capabilities, and as long as there is a vat large enough to successfully melt plastic, almost any large object can be coated too. PVC is the third most widely used plastic coating product and serves as an alternative to plastisol when more flexibility is desired.
PVC coated products exhibit good chemical and water resistancy and so are used in products such as wires, chords, wire mesh, frozen food shelving, dishwasher baskets and chain link fences. Plastic is also an insulative material and PVC often coats electrical components such as jumper cables or extension cords and serves as a thermal and electrical insulator.
PVC coating can also go through testing to become FDA approved for use in food processing applications. As with other forms of plastic manufacturing, PVC coating can be adjusted in terms of color, texture, thickness and rigidity according to custom specifications.