GMNA - 9986329
Waterborne Basecoat Component of Integrated Topcoat System
|Publication Date:||1 April 2019|
This specification covers the qualification and performance requirements of waterborne (WB) basecoat (BC) that is applied to rigid substrates.
Material Description. These basecoats are WB technologies and are components of rigid topcoat systems that are used in conjunction with 9984515 and 9986328.
Symbols. Not applicable.
Applicability. The WB BCs are typically applied to dehydrated WB BC compatible primers per 9986328 which have been applied to the electro-coated metal surfaces or appropriately primed rigid plastics. Following the BC application, heated flash is employed to dehydrate the BC prior to solventborne clearcoat (CC) application per 9984515. Specific heated flash temperatures are dependent on supplier technology and heated flash design conditions needed to achieve prescribed dehydration levels. Following the 9984515 CC application, the entire system consisting of the primer layer, BC layer and CC layer is baked simultaneously in a single bake, as described in 3.2.
Remarks. Each combination of BC compatible primer (BCP), BC and 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 plant-specific layering, ancillary materials and processing must be conducted before release.