Description / Abstract: This specification covers the requirements of a twocomponent (2K) urethane monocoat used on chrome plate, exterior vehicle applications. These requirements cover part performance and general process methods for ensuring long-term integrity of the coating system.

Material Description. The paint is a 2K urethane monocoat used over chrome-plated, exterior vehicle applications. This specification is in reference to 2K urethane monocoat paints that are pigmented. It does not pertain to paints where the intent is to clearcoat or tint. These paints are designed specifically for obtaining excellent adhesion and weatherability to chrome-plated surfaces. All qualified paint systems used for this application shall meet GMW3005 generic topcoat performance requirements. In addition, supplemental test requirements listed in Table A1 are required. Paint systems that meet these requirements can utilize a primer or be single-coat applications. This specification does not apply to paint systems designed to be applied over resist coats. Although these paints can be applied over resist coats, 9984255 covers resist and topcoat applications specifically. Any paint in contact with chrome shall meet the requirements of this specification. This also applies to parts with a combination of resist coating and paint on chrome.

Although primarily intended for use on chrome-plated plastics, this 2K urethane monocoat paint may be qualified for use on other substrates, such as metal. The final surface must be chromiumplated.

These coatings are part of a total painted product system and must meet the requirements set forth in this specification and those shown on engineering drawings. Approved Paint on Parts Specification (APOPS) GMW14797 is required. APOPS requirements are specific to any given combination of plastic substrates, chrome finish, physical plating line and physical painting line. APOPS submissions shall also include supplemental testing listed in Table A1.

Symbols. Not applicable.

Typical Applications. Typical applications are grille black-out areas and emblems. Paint on chrome is generally used for cost savings when compared to resist and topcoat. In other cases, a two-part component construction may be used with one piece being chrome-plated and the other molded in color or painted part. Less masking, multiple components, and more than one pass of paint can be avoided with paint over chrome. Some durability may require compromise. For example, resist and topcoat painting will provide better hiding of small metal chips of the chrome below the paint surface. Trace appearances of chrome through the paint can occur if the part is impacted by stones or other objects. The use of paint on chrome compared to resist and topcoat should be evaluated prior to design release.

Remarks. Not applicable.