Automotive manufacturers and tier suppliers have used pressure-sensitive adhesives (PSAs) for many years in a variety of automotive applications. As lightweighting and electrification evolve, PSAs are suitable for a growing number of applications as assembly process engineers globally take advantage of advances in chemistries and material configurations.
Corporate average fuel economy (CAFE) standards and international regulations that require vehicular efficiency have led manufacturers to reduce vehicular weight. Fractions of an ounce can make a difference when added up, qualifying PSAs as a choice for tasks once performed by mechanical fasteners.
Lighter materials, such as plastics or thinner metals, reduce vehicular weight as well. Replacing medium surface energy (MSE) plastics such as acrylonitrile butadiene styrene (ABS) and polycarbonate – very stiff materials – will continue with lighter, low surface energy (LSE) plastics such as polyethylene and polycarbonate, and the adhesives used must change with the materials.
Polypropylene fuel tanks, for example, are replacing MSE materials. The tanks require heat shielding for protection from extreme vehicle temperatures to avoid melting. The right adhesive in this scenario must hold its bond for the life of the vehicle; be resistant to automotive fluids such as gasoline, oil, and transmission fluid; and protect against water and salt spray. LSE-modified acrylic adhesives with tackifiers that soften the adhesive for higher flow and increased tack support such uses.
Noise, vibration, harshness (NVH)
Whether it is vibration damping to reduce interior sound levels or acoustical absorption materials that prevent noise from getting into the cabin, foams and related materials have been key elements in the fight against NVH for years. NVH materials are now common in doors and headliners of all classes of vehicles – once unheard of for lower-end models.
However, with lightweigthing mandates, older NVH-mitigating materials are not always suitable, requiring changes in adhesives. Heavily textured materials, for example, may require a higher coat weight adhesive to provide a solid bond to the material.
Some tapes deliver ideal performance in many NVH applications. Avery Dennison FT 8392 high-performance foam bonding tape features an acrylic side that laminates well to a wide variety of foams, providing dimensional stability and good die cutting characteristics. A rubber adhesive side bonds well to LSE plastics, such as polypropylene. In addition, a biocide inhibits mold growth – something becoming more common in original equipment manufacturer (OEM) specifications. It also withstands the high temperatures sometimes found in cabin interiors.
Planning for trends
Design engineers should work with tape converters and tape manufacturers as designs are made, so the team can provide full consideration to the materials being bonded and the environments encountered.
Stick together from the outset, and your critical components parts will stick together as well.