But there's a new challenge: making them eco-friendly. This article dives into the challenges faced by the pressure-sensitive adhesives world in going green. We're not just making adhesives that work; we're making them work without harming the environment.

We'll walk you through the challenges, from using recycled materials to dealing with the demand for lightness, while also showcasing some of the ways in which we’re meeting those challenges head-on. We'll show that we’re also putting this best practice into action, with examples of how we're making our processes as sustainable as possible throughout our facilities.

The desire for greater sustainability is increasing the usage of environmentally friendly materials across the industry. This includes recycled plastics, as well as new types of polymers and blends. For adhesives to be effective, they need to be tested for each substrate as the adhesion may vary. It’s also important to test if the tape or label will last for the expected lifetime of a vehicle, while also exposing it to various environmental conditions, including temperatures, humidity, chemicals, and even UV light.

The introduction of new materials can present challenges for adhesives as the traditional ways of bonding may no longer work as effectively. For example, we can't use welding or brazing when we swap metal parts for polymer compounds. Even using screws or bolts might need a change in how the parts are shaped, and we have limits on space.

Adhesive bonding can be an option, but qualification testing on new or lightweight materials must be performed as they often feature different surface shapes and qualities. To ensure the adhesive works well, considerable testing is required to see if it endures or peels off under different conditions, like changing temperatures and humidity.

The material's operating environment gives engineers plenty to ponder. For instance, plasticizers, waxes, and other molecules can migrate to the bonded surfaces, the impact of oxidation and ultraviolet radiation, and any outgassing from these materials can all impact the solutions we use.

At the heart of any sustainable solution is the selection of the appropriate materials. For instance, pressure-sensitive adhesives can be found in both robust and delicate applications for decorative and functional parts of the vehicle. These adhesives can be found in a wide range of safety and comfort features like sensors and keypads, airbags, and seat heating while the more demanding applications include wire harness tapes under the hood where high temperatures are common.

Polyethylene Terephthalate (PET) is another important material in the journey toward a more sustainable future. PET is used to construct functional films, performance tapes, and labels for automotive applications. PET is used in automotive solutions because of its stability,  resistance to heat and friction, and it’s nontoxic.

PET films come in many different calipers and types, including of different thicknesses, dual or single-side treated, and various special properties. Whether used as a facestock or liner, they lend themselves to being coated with functional layers, including adhesives. PET is produced from crude oil, therefore it is critical we consider how to reduce, reuse, or recycle these materials in order to preserve our resources and protect the environment.

Where paper liners cannot be used, the collection of used PET liners allows for these to be recycled and AD Circular is a service that we offer to the industry. Where the component is made of PET, it may be recycled, with the label, film, or tape in place; otherwise debonding before recycling is also possible with pressure-sensitive adhesives.

Sustainability requirements for labels in the Automotive industry motivate Avery Dennison to use recycled films rather than virgin material, which reduces labels' CO2 footprint and GHG (greenhouse gases), conserving energy, and fossil fuels. Avery Dennison is sourcing and developing sustainable labeling solutions using 70% rPET recycled content (post-consumer waste, chemically recycled). The same motivation is behind the development of rPET materials in performance tapes, where the target is to deliver the expected performance at an acceptable cost.

Ultimately, these sustainability efforts need to become commonplace throughout the supply chain. We’re striving to be at the forefront of sustainable practices and are aiming to lead the way in reducing the environmental impact of production. For instance, in Rodange, Luxembourg, we made significant sustainability improvements through collaboration with external experts and suppliers, and increased engagement of site personnel. This has enabled us to reduce gas consumption by 25% since 2015, even as production has increased. 

We're also utilizing renewable energy at our site in Turnhout, Belgium, and are developing a solar array to heap up the ovens we use in our various processes. Our processes are rooted in creating a circular economy both in our own work and also throughout our supply chain.

Our task is to find the right balance of materials that offer the best performance, serve the demanding needs of the automotive industry, and reduce the environmental impact. 

By identifying ways to improve our products, we can positively impact supply chain integrity. One way we do this is by sourcing from suppliers that comply with regional governance.

Developing sustainable adhesive materials begins with partnerships and continues with realistic goals. These goals must reduce the use of virgin resources and waste management and provide customers with responsible and sustainable solutions.