This specification covers the performance and qualification requirements for a flexible, exterior, waterborne, onecomponent (1K) basecoat/ low-gloss, two-component (2K), solventborne, etch-resistant, clearcoat topcoat system for use over flexible plastic substrates, typically Thermoplastic Polyolefin (TPO) or Reaction Injection Molded (RIM), over a bake latitude of approximately (115 to 135) °C ((240 to 275) °F).

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.

Basecoat components of these systems are typically 1K waterborne technologies. Clearcoat components of these systems are flexible, 2K solventborne urethane or urethane blends. Each combination of specific basecoat and clearcoat shall be tested and approved as a basecoat/clearcoat system. The individual components are not interchangeable and are approved for use only with combinations of basecoat/clearcoat of the total paint system which was used in the qualification testing. It shall also be compatible with specific adhesion promoters and/or primers used with specific plastics.

Qualified to this Material Specification.

Each combination of specific basecoat and clearcoat shall be tested and approved as a basecoat/clearcoat topcoat system. The individual components are not interchangeable. This specification shall be used in conjunction with the GMW14797: Approved Paint on Plastic System (APOPS), a section of the GM Materials Approval Source List (GMMASL), which lists the approved substrate, cleaning, priming, and topcoat combinations. In addition, the topcoat system is part of the total coating system and shall meet qualifications set forth in this specification and those shown on engineering drawings for appearance and durability.

Symbols.

Not applicable.

Applicability.

These topcoats are typically designed to be applied over an adhesion promoter or a bake primer. All TPO substrates using GMW18626 shall be applied over an adhesion promoter (GMW18414 or GMW18415) or flame treatment per GMW16133.

Remarks.

None.