This specification covers the qualification and performance requirements of waterborne basecoat compatible primer (BCP) that is applied to rigid substrates.

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose/Material Description.

These primers are waterborne technologies and are components of rigid topcoat systems that are used in conjunction with GMW18521 and GMW18532.

Symbols.

Not applicable.

Applicability.

These waterborne primers are typically applied to electro-coated surfaces or appropriately primed rigid plastics. Following the primer application, heated flash is employed to dehydrate the primer prior to waterborne basecoat application per GMW18532. Specific heated flash temperatures are dependent on supplier technology and heated flash design conditions needed to achieve prescribed dehydration levels. The waterborne basecoat is then applied and dehydrated in a heated flash. Following the coating layer of clearcoat application per GMW18521, the entire system consisting of primer layer, basecoat layer and clearcoat layer is baked simultaneously in a single bake, as described in 3.2.

Remarks.

Each combination of basecoat compatible primer, basecoat (BC) and clearcoat (CC) must be tested and approved as a topcoat system. The individual components are not interchangeable between suppliers unless otherwise tested. In addition, the topcoat system is part of the total coating system and must meet qualifications set forth in this specification and those shown on engineering drawings. Validation testing for plantspecific layering, ancillary materials and processing must be conducted before release.