3 Lessons Flexible Packaging Can Learn from PET Bottles

Do you remember soda bottles of the 1970s? When bottles were chunky and much heavier than they are now?

Back then, beverage companies sold their products in plastic bottles made of a mixture of materials. The combination of aluminium screw cap, plastic (either polyethylene terephthalate – PET – or acrylonitrile) and hard black plastic base glued to the body of the bottle, made recycling difficult.

When acrylonitrile was thought to be carcinogenic, PET became the front runner as the favorable material, and it quickly became standardized across the beverage industry. With the industry using the same materials, widespread collection and recycling of PET bottles was established. But it didn’t happen overnight. The journey to PET bottle recycling took many years and involved every part of the supply chain.

So what steps were taken exactly to achieve this? And, more importantly, what lessons can flexible plastic packaging learn to help speed up the journey to widespread recycling?

Step 1: Innovation

The first plastic bottles for carbonated soft drinks were developed by Coca-Cola in 1975. Six of the “Easy-Goer” lightweight plastic bottles were lighter than one glass bottle of comparable size. What’s more, they used less energy than glass bottles in the manufacturing and transporting cycle. Unfortunately, the material used for these bottles – acrylonitrile – was not recyclable and produced toxic fumes when burned.

In the meantime, DuPont field engineer Nathaniel Wyeth was busy trying to create a plastic bottle for carbonated drinks that wouldn’t explode. Replacing acrylonitrile versions and the original glass bottle with PET was the solution, and in 1973 he patented the process in the US. In 1978, Coca-Cola introduced a two-liter PET plastic bottle to market. This new, clean, easily recycled material could be injection-molded into test tube shaped ‘preforms’ and then stretched to form bottles. The “footed base” we’re now familiar with was created, which helped the PET bottle withstand the pressure of carbonation.

Lesson learnt for flexible packaging:

The PET equivalent for flexible packaging is polyolefin. This works better for flexibles because of its high puncture resistance and strength, which allows for a variety of irregular-shaped items to move through the supply-chain life cycle without being damaged.

Today, most flexible plastic packaging is made up of a range of different materials (including PET, polypropylene, polyethylene (PE), aluminium, and paper). In 2018, Amcor Flexibles achieved an innovation breakthrough: it developed a recyclable PE film that also provides high barrier protection. With this innovation, recyclable flexible packaging moved a step closer to mass standardization.

Step 2: Standardization

PET quickly became the most commonly used material across the beverages industry. Its unique combination of properties contributed to its global growth and universal acceptance. These include transparency, strength and toughness, low gas permeation rate, non-toxicity, a wide range of usage temperatures, and ability to be easily depolymerized and repolymerized (which facilitates cleaning).

PET bottles can be easily recycled and then converted into fibers for things like carpet and clothing, strapping, and building materials to name but a few. It also made good economic sense for brand owners to switch to PET: it cut shipping costs considerably, because more containers could be sent in the same size vehicle.

However, to be successful, the transition from two- to one-piece bottle technology required an industry-wide effort. The entire supply chain – from manufacturers through to consumers – had to be educated to maintain the conditions (up to 113F/45C degrees and internal pressures exceeding 90 psig (6 bar)) necessary to avoid product failure. Today, that effort has paid off in the form of an extraordinarily safe, efficient and recyclable bottle that is used by beverage companies large and small around the world.

Lesson learnt for flexible packaging:

Flexible high barrier and retort packaging is increasingly popular, and since it's launch in April 2019 customers have started using Amcor’s new recyclable flexible laminate on their machines. One of Amcor’s tasks is educating customers on the benefits of this new breakthrough film. Not only does its lighter weight reduce carbon footprint and cut shipping costs, but it can also be recycled. By growing awareness and adoption, polyolefin films for flexible plastic packaging will gradually become the industry standard.

Step 3: Mass recycling

The expanded market for PET-based packaging increased the mandate for companies, together with government, to develop means of recycling it. By the end of the 1970s, in a consumer culture that craved convenience, people increasingly paid attention to the landfill crisis and the problem of nonreturnable containers. In response, companies including Pepsi-Cola and Coca-Cola campaigned for municipal recycling systems, testifying before the US Congress to secure more support from federal government.

As a result, curbside recycling programs became more widespread. By 1992 there were over 4,000 such programs across the US. In the same year, Johnson Controls (the world’s largest manufacturer and recycler of batteries) engineers – together with Coca-Cola – pioneered the first ‘bottle to bottle’, closed loop recycling technology. This was able to recover PET from post-consumer use packaging and clean it sufficiently to be reused with virgin materials in new packaging.

However, first the technology had to meet FDA regulations for food contact, and a challenge test was developed. In 1994, the very first ‘Letter of Non-Objection’ was awarded to Johnson Controls and Coca-Cola for the integrated recycling facility Johnson Controls built in Michigan. That first facility recovered around 15 million pounds of PET per year, and became a model for installations around the world. It was the birth of the modern plastic recycling industry as we know it.

Lesson learnt for flexible packaging:

‘Designing for recycling’ means nothing if the infrastructure isn’t in place to collect and recycle the packaging. So, for widespread flexible plastic packaging recycling to become a reality, we need to engage with industry, policy makers and cross-value chain organizations.

This is why forthcoming guidelines from organizations such as the Ellen MacArthur Foundation and CEFLEX are so important. These will align raw material suppliers, converters, brand owners, retailers, sorting and recycling facilities and regulators on how to realize a circular economy for flexibles.

Follow our journey as we design for recycling and reuse, increase the volume of recycled materials in our products, and work with others to help build the recycling infrastructure we urgently need to protect the planet.