Painting plastics

The development of plastics offers many advantages that justify their use:

• low density, a crucial advantage in the automotive and aerospace industries;

• durability, corrosion resistance and shock resistance;

• greater freedom of form, highlighted by the design;

• easy integration of functions ;

• lower investment costs, facilitating more frequent form renewal.

Designers' requirements and the durability of plastics often call for painted parts, to give them the protection and appearance they need. Painted plastics are often in competition with the same mass-colored plastics, which are generally less expensive but cannot guarantee a durable appearance over time. As a result, they are confined to applications where durability is not an essential factor. Painting plastics gives them an appearance similar to that of painted metal parts, ensuring their integration into complex assemblies with a uniform appearance. Numerous industries apply paint to plastic materials: household appliances, electrical engineering, medical equipment, the toy industry and, above all, the manufacture of pleasure boats, but it is the automotive industry that makes the greatest use of this finishing process, both for the passenger compartment and the bodywork. It's for this reason that the examples chosen to examine the problems of painting plastics come from this industry. We'll also look at the constraints that force us to be extremely vigilant when it comes to choosing and using the plastic/paint combination.