GMW 3041 Performance Requirements for Bonding and Sealing of Fixed Automotive Glass

In the standard “GMW 3041 Performance requirements for bonding and sealing fixed automotive glass” developed by General Motors, the material is defined as follows:

• Typically a one-component, hot or cold temperature applied, moisture-curing, black polyurethane adhesive sealing compound
• Two-component chemical cure systems

These adhesives are used with compatible glass side and body and substrate primers to bond automotive glass to body openings. Depending on compatibility, they can be used with or without a primer to bond to certain paint systems, plastics or metals.

Applications for materials approved to this standard include bonding and sealing fixed automotive glass. These typically include windshields, rear windows, fixed trunk lids, side and encapsulated glass. Materials approved to this requirement are generally designed to bond the above-mentioned automotive glass to painted body openings. Compatibility with other substrates is not limited to, but may include, reaction injection molding, polyvinyl chloride (PVC), sheet molding compound or thermoplastic elastomer.

In this standard, the material requirements are determined as follows:

• For the requirements on test samples, the standard “GMW 3221 Standard conditioning of organic materials” applies.
• All samples must be conditioned according to Code A of the GMW 3221 standard before each requirement test.
• Adhesive sealant compound material properties must be provided at the time of material approval and documented in the specific material specification when published.
• Viscosity is tested at a temperature of 22 degrees plus/minus 3 degrees and a relative humidity of 50 percent plus/minus 5 percent.
• The odor is tested with a cured 3205 cm × 1 cm cross-section, 1 cm long, approximately 25 mL bead, according to standard GMW 25. The minimum degree of odor shall be six.
• Visual inspection is done for color.
• For volatile organic compound (VOC) determination, the Environmental Protection Agency (EPA) Test Method 24, Procedure B or VDA 278 standard is used.
• Specific gravity is determined according to the ASTM D1475-13 standard.
• Solids content is calculated based on VOC data from EPA Test Method 24.
• Adhesive sealant compound material properties are provided during material approval and documented in the specific material standard.
• Shore hardness tests follow ISO 868. All readings must be within the specified tolerances when tested on a single bulb under each of the following conditions:
  • It is cured for 22 hours at 3 degrees plus/minus 50 degrees temperature and 168 percent RH relative humidity.
  • After 22 hours of curing at 3 degrees plus/minus 50 degrees and 168 percent RH relative humidity, it is tested at minus 30 degrees plus/minus 3 degrees for 4 hours. A maximum of 168 points increase is allowed in the 15-hour room temperature value.
  • After 22 hours of curing at 3 degrees plus/minus 50 degrees and 168 percent RH relative humidity, it is kept at 70 degrees plus/minus 3 degrees for 336 hours and tested at 22 degrees plus/minus 2 degrees. A maximum of 168 points increase is allowed in the 15-hour room temperature value.
• The module must comply with the GMW 15329 standard.
• Elongation shall be in accordance with Method A of ASTM D412-16 standard.
• The tensile test for fixed glass connection shall comply with the GMW 15736 standard.
• Young modulus should be in accordance with ASTM D638-14 standard.

In this standard, the production process is described as follows:

• Material process capability: Materials approved to this standard must have the ability to be distributed and processed by standard production equipment. A production process study must be completed to demonstrate capability.
• Minimum top coat film build-up: When bonding to the top coat, a minimum of 20 µm clear coat film build-up is required on all bonding surfaces without adhesive separation between paint layers.
• Requirements for the delivery of glass bonding adhesives to an assembly facility: Unless otherwise specified by the responsible General Motors engineering group, all requirements of the GMW 17350 standard must be met for the delivery of glass bonding adhesives to a General Motors assembly facility.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also test services in accordance with the standard "Performance requirements for bonding and sealing of fixed automotive glass GMW 3041".