Temperature effects automotive adhesives

The dominating chemical pretreatment used in Europe for molded automotive TPO components is flame treatment. The effectiveness of the flame treatment is checked by surface tension measurement and should be a minimum of 45 dynes/cm to ensure acceptable adhesion with solvent-based paints. Chemically, the adhesion effect of flaming is based on a controlled oxidization of the CH2-and CH3 units (7). Also, a degradation of the polymer and polymer melting can occur therefore the flaming needs to be carried out within an upper and lower temperature limit. 

Thermoplastic resins make excellent materials for use in automotive reflectors by allowing for design flexibility while demonstrating capability under demanding conditions. With many materials to choose from, comparing the performance of various resins at use temperatures is important. The effects of metallization conditions are described as they relate to the metal adhesion requirements for automotive reflectors. Some material limitations can be overcome through modifications to the metallization process. Moisture is a critical factor that affects both the metallization conditions as well as metallized thermal performance. Materials that can demonstrate strong polymer/metal adhesion are less affected by moisture than those with lower metal adhesion. 

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