Weighty matters

3 mins read

Vehicle lightweighting has become a ‘must have’ for motor manufacturers – and adhesive tapes are now delivering advantages over traditional mechanical fixings that are helping to drive this expectation to even greater heights.

Despite a recent period of sustained prosperity, latest figures from the Society of Motor Manufacturers and Traders (SMMT), indicate that 1.67 million cars were produced in UK factories last year, a decline of 3% compared with the year before. Uncertainty has affected multiple industries in recent times, so, to address this decline early, many manufacturers are seeking out new methods of increasing productivity and keeping costs down, whilst also adhering to increasing environmental standard scrutiny.

In response to the innovation requirements synonymous with the automotive industry, adhesive tape has quickly become a key component in many production processes. Tapes are used under the bonnet, on the body and the interior and exterior trims of the car, where they offer various benefits over traditional joining technologies. With the continuing drive to keep vehicle weight to the minimum, one leading producer of adhesive tapes says these offer “a clear advantage over traditional mechanical fixings”. As such, it is working with the automotive industry to find tape solutions that, tesa states, “benefit manufacturers, the environment and ultimately the end customer”.

When considering attachment part mounting, product solutions are required that work for plastic to clear coat, plastic to plastic and plastic to metal applications. This constructive bonding can be very challenging and time-consuming, as dissimilar materials give different coefficients of thermal expansion, so, when they warm up or cool down, they expand and contract at different rates. In addition, parts that need to be bonded to a vehicle’s exterior have different levels of surface energy.


tesa produces a wide range of double-sided tapes that can be applied at low temperature to low surface energy materials, without the need for a primer. “Applying primer as part of the attachment part mounting technique is an expensive, elongated and hazardous process,” says tesa’s UK automotive sales manager Richard Powell. “By skipping the primer, the production process becomes more environmentally friendly, total process cost and complexity is reduced, robust application is ensured over a wide temperature range and near-ultimate peel adhesion levels are reached within a minute on most substrates.

“Current solutions on the market need hours, or sometimes even days, to achieve the same level of performance, meaning adoption of tapes as an alternative can make a significant impact to the production lines efficiency and output.”

He describes tesa 64912 PE foam tape, the first foam tape introduced into the marketplace that can be applied in temperatures as low as 5˚C. “It is used extensively in the automotive industry to permanently mount small similar and/or dissimilar parts, such as parking distance sensor brackets, make and model badges, and interior and exterior plastic bonding, such as entry trims. A PE foam core with adhesive lamination provides high-performance adhesion on low and medium surface energy materials, reaching ultimate peel immediately after application and offering excellent converting properties.”


Similarly, tesa ACX technology is said to take the production of tape chemistry forward a generation by enabling a functional combination of its chemical components. “While acting as a solvent-free coating of high-performance acrylic systems in thicker formats, enhanced performance is seen in the strength of its bonding power, strength dissipation and application” adds Richard Powell.

Further advantages claimed when using tesa ACX over traditional methods include clear full-surface bonding, extreme load capacity, corrosion prevention and good aesthetic results. “When mounting automotive attachment parts with self-adhesive tapes, the tape will not be visible after the part has been attached to the car body, enhancing overall appearance and ultimately customer satisfaction. In addition, the acrylic adhesive system enables optimal wetting and chemically adapts to bonded surfaces, while also fulfilling requirements such as vibration, noise prevention and shock absorption, and sealing against liquids.”

So, what exactly is tesa ACX 778XX? It’s a double-sided, triple-layer, symmetrically designed acrylic foam tape engineered for automotive exterior attachment part mounting. Coated on both sides with LSE adhesive, its strengths are in offering high initial performance on LSE plastics, as well as on difficult-to-bond OEM clear coats. In addition, its viscoelastic acrylic foam core absorbs and dissipates dynamic and static loads. “Likewise, tesa ACX 777XX has been developed to securely bond exterior attachment parts to the easy-to-bond car body. A unique double-layer asymmetrically designed product, it is coated on one side with LSE adhesive for high initial performance on LSE plastics,” states Powell.


Applications said to be already benefiting from this viscoelastic technology include body side, door edge and boot mouldings, aero-flaps, brake-light spoilers, fender flares, rocker panels, ‘shark fin’ antennas and roof ditch trim and rails – all joined gently, yet set to withstand any external influences throughout a vehicle’s lifetime. Since the introduction of tesa ACX, the product has gained many industry plaudits, including official approval from European, North American and Asian OEMs.

Powell further comments: “With the elimination of the primer process, converters and manufacturers can provide a much healthier working environment. In addition, with a much simpler process, easier control and handling, production times are shortened, providing additional cost savings and not affected by seasonal temperature in the production areas.”

Lumps and bumps caused by screws and bolts will soon be a thing of the past, he predicts. “Wire harnessing is already widespread in future-proof hybrid vehicles and tesa already produces tapes offering an excellent bond that is resistant to both heat and abrasion. From a customer satisfaction point of view, vehicle weight is an integral factor, with lightweighting having a significant effect on fuel economy, sustainability and the realisation of better processing efficiencies and improved overall performance.”