Design Life-Cycle

Long Yat Job Tam

SAS 43

Professor Christina Cogdell

3/10/2023

Raw Materials in Life Cycle of Tetra Pak Juice Box Cartons

The juice box carton is a well known product used for carrying beverages, it is important to study its sustainability because of the use of plastic materials in its manufacture. Examining its environmental impact from a life cycle perspective shows that the raw materials acquisition and recycling and disposal stages contribute to the most environmental impact.

The acquisition and disposal of polyethylene and aluminum contributes to the most environmental impacts of the juice box carton through downcycling, however raw materials acquisition is another major factor. Contrary to popular belief, the majority of juice boxes being disposed directly to landfills and the disposable nature of juice boxes contribute to significant environmental and social impacts.

            I will be looking specifically on the design and manufacture of Tetra-Paks, as they are a form juice box carton popular in many parts of the world. Tetra-Paks are made of three main materials: paperboard, polyethylene, and aluminium foil. According to Tetra Pak company website, the paperboard is the skeleton that maintains the structure of the carton, the aluminium foil protects the beverage from light and oxygen, and three layers of polyethylene further protect the beverage contents from the outside and the packaging itself (“Packaging Material”).

            The production of paperboard involves the use of trees as raw material. According to packagingschool.com, trees are cut down into logs, and then stripped of their bark through a debarking drum. Next, through a chipper machine, the logs are sliced into small wooden chips. The chips are refined into fibers, which are washed with water and bleached to make mechanical pulp (Keigley). This type of pulp that comes directly from freshly logged trees, is also known as virgin pulp, as the material is being used as paper for the first time, without any traces of recycled wood pulp. The Turkish tissue paper organization PaperTR stated that virgin pulp is of higher quality than recycled pulp. As the fibers in recycled pulp are weakened and shortened over continued recycling processes, virgin pulp is needed to continue paper manufacturing (“Virgin Pulp”). Layers of mechanical pulp and chemical pulp (made of wood fibers and chemicals) are then pressed together, dried, and then coated with a chemical solution in order to provide strength properties to the paperboard (Keigley), which in turn help the Tetra Pak maintain its shape throughout its life cycle.

            Meanwhile, the raw materials used to make aluminum foil mainly come from aluminum, and in turn, bauxite mineral deposits. Aluminum does not come in pure form naturally, but found in many different mineral deposits such as bauxite. According to Kerry,
“bauxite is a reddish-brown clay-like deposit containing iron, silicates and aluminium oxides,” with its mineral deposits found in many parts of the world (Kerry 165). Mined bauxite is refined to remove impurities to create aluminia (or aluminum oxide). To further extract the aluminum from the aluminum oxide, heavy uses of electric currents run through the aluminia at high temperatures (Cogdell, “From World War I to the 1960s”). The extracted molten aluminum is then cooled into large metal slabs, then rolled and flattened into very thin sheets of aluminum foil, with its thickness measuring less than 150 micrometers (Kerry 168). In addition to its properties of being an effective barrier to protect a beverage from reacting with outside light and air, aluminum foil is also very light in weight, does not react to the beverage contents of a juice box, and is resistant to temperatures up to 150 degrees Celsius (Kerry 163). These properties make aluminum an ideal component for long-term storage for juice boxes without requiring refrigeration.

            The third component of Tetra Paks, polyethylene, comes from natural gas. Ethene is extracted from the natural gas, compressed, and cooled. Then, the compressed ethylene enters a reactor, where the ethylene gas reacts with chemical enzymes and initiators to create polyethylene (Royal Society of Chemistry). The ethylene molecule’s carbon double bond breaks down with the help of the catalyst to create a long, continuous chain of carbon atoms and ethylene molecules (Sharpe). This chemical process allows the polyethylene mixture to become a molten solid, then later cooled, dried, and sliced into tiny plastic pellets (Royal Society of Chemistry). While the Tetra Pak website does not talk about what specific form of polyethylene they use for juice box manufacture, we can safely assume that Tetra Paks are coated with thin layers of polyethylene or perhaps film. The polyethylene manufacture takes the plastic pellets, melts them, and inflated with air to create a continuous thin sheet of molten plastic (“Polyethylene Film”). Polyethylene carries many beneficial properties. Like aluminum foil, it is malleable and temperature resistant (“Polyethylene Film”). But polyethylene also is resistant to water and chemicals, making it ideal to package food and beverages (“You Use It Daily”).

All the three major components of the Tetra Pak juice box carton through lamination and Tetra Pak assembly machines. During the carton manufacturing process, as seen in the show How It’s Made, the paperboard is printed with the juice box design, then creased with fold lines, then laminated together with the polyethylene layers and aluminium foil. Hot gas and liquified plastic is used to strengthen adhesion between the paperboard and aluminum with the plastic (“Episode 142”). This laminated paperboard, aluminum foil, and plastic combination is placed into a Tetra Pak patented machine to assemble the cartons. The laminated material is sterilized in peroxide, heated, and shaped into a tube form. In this form, the machine then pipes in the liquid beverage product inside the laminated tube. Once filled with the beverage, the carton is cut and sealed by the machine into the rectangular shape, and ready for distribution (“Tetra Pak A1 TFA Animation”).

As Tetra Pak factories and the use of Tetra Pak cartons are distributed widespread around the world, we can assume that to transport and distribute the cartons, the raw materials needed for this part of the life cycle are fossil fuels. Crude oil and natural gas is needed as fuel to power thousands of trucks, ships, and planes to deliver the juice boxes. The multiple layers of materials used in the Tetra Pak carton material help to keep delivery of the juice boxes and the beverage inside relatively stable without need for refrigeration, as long as the carton seals are not opened or the box damaged (“Understanding Tetra Pak Packaging”).

Tetra Pak cartons do not require any more raw materials during use. The convenience to store Tetra Paks in a cool, dry location (as it says on some juice boxes) for long periods of time without the need of using energy for refrigeration make it an incredibly useful product. However, once the juice box’s seal is opened and beverage content is consumed and depleted, the carton is usually immediately disposed of. Tetra Paks cannot be reused, resealed, or refilled with sterilized beverages. This one-time-use nature of the Tetra Pak, along with other disposable products such as plastic utensils, makes the Tetra Pak extremely wasteful.

The Tetra Pak company argues that Tetra Paks can be recycled into new uses and products. According to a recent sustainability report by the company, out of 183 billion Tetra Paks sold in the year 2020, only about 50 billion of the cartons were recycled (“Sustainability report 2021” 8), which means 72.7% of all cartons were sent directly to landfills for disposal. For the minority of used Tetra Paks that do get recycled, the cartons are sent to a shredder where the cartons are ripped into pieces. Then, the carton pieces are sent to a pulper machine, where they are submerged in water and the paperboard is separated from the plastic and aluminum. For paperboard, it can be recycled for paper products such as office paper. But due to the lower quality of the recycled pulp, it cannot be used again to make new juice box cartons (Miles). Unfortunately, it is impossible to separate the aluminum and polyethylene layers. It is claimed by the Tetra Pak company that the combined aluminum and plastic is used as polymer material for uses in cement, or as some form of low-cost material for walls and furniture (Miles). Looking at this recycling and disposal process, in terms of raw materials, it seems that fossil fuels were once again involved in transporting disposed cartons, to power the machines that separated the carton material layers via the power grid, and water was needed for the pulper machine.

Looking at the life cycle stages of a Tetra Pak as a whole, it seems that juice box cartons are ultimately not sustainable. While trees that are used to make paperboard can be replenished relatively quickly over decades, natural gas that is needed for polyethylene may take millions of years to replenish (Cogdell, “The Steam Engine”). As mentioned on an environmental sustainability focused blog Treading My Own Path, used Tetra Paks are not recycled to make new juice box cartons. Instead, Tetra Paks are just “downcycled” for uses in other products, which eventually just end up in landfills (Miles). Ultimately, this just defeats the whole purpose of recycling and will not prevent materials from cartons to reach landfills. While the Tetra Pak carton is extraordinarily convenient for consuming beverages without worrying too much about preservation due to the carton’s flexible, strong, and protective materials, the disposable one time usage of the product, combined with the complicated nature of the combined carton layers make it costly in energy to even downcycle the product. As consumers, we need to be mindful of our choices in the use of certain products, in this case, for beverage consumption. Using reusable drink containers, such as water bottles or metal or glass containers can help with reducing excessive waste. Finally, from a personal standpoint, this research project generally taught me to rethink about the daily products I use, their waste content, and to take proper steps and even sacrifices in daily habits to live a more sustainable lifestyle.

References

Cogdell, Christina. “From World War I to the 1960s: Plastics, Aluminum, and Waste Colonialism.” 2 Mar. 2023, U.C. Davis. Lecture.

Cogdell, Christina. “The Steam Engine and the Industrial Revolution.” 16 Feb. 2023, U.C. Davis. Lecture.

Emblem, Anne, et al. “9 Aluminum Foil Packaging.” Packaging Technology: Fundamentals, Materials and Processes, Woodhead Publishing, Oxford, 2012, pp. 163–177.

“Episode 142.” How It's Made, season 11, episode 12, Discovery Channel (Canada), 26 Nov. 2008. https://www.youtube.com/watch?v=R7HgG4a3jJA.

Keigley, Kevin. “How Is Paperboard Made?” The Packaging School, 5 Feb. 2020, https://packagingschool.com/blog/2019/09/04/how-is-paperboard-made/.

“Low Density Polyethylene (LDPE) Production Overview.” YouTube, Royal Society of Chemistry, 16 July 2015, https://youtu.be/5NyjH26RIPI. Accessed 16 Mar. 2023.

Miles, Lindsay. “Why Tetra Paks Aren't Green or Sustainable.” Treading My Own Path, 21 Dec. 2019, https://treadingmyownpath.com/2014/09/11/why-tetra-paks-arent-green-even-though-theyre-recyclable/.

“Packaging Material for Tetra Pak Carton Packages.” Tetra Pak, https://www.tetrapak.com/solutions/packaging/packaging-material/materials.

“Polyethylene Film: Discover How It Is Made.” Geartech BR, 18 Feb. 2020, https://geartechbr.com.br/en/polyethylene-film-discover-how-it-is-made/.

Sharpe, Pete. “Making Plastics: From Monomer to Polymer.” American Institute of Chemical Engineers, 26 July 2016, https://www.aiche.org/resources/publications/cep/2015/september/making-plastics-monomer-polymer.

“Sustainability Report 2021.” Tetra Pak, 2021, https://www.tetrapak.com/content/dam/tetrapak/publicweb/gb/en/sustainability/TetraPak_Sustainability_Report_2021.pdf.

“Tetra Pak A1 TFA Animation.” YouTube, VirtuellDesign.se, 12 Nov. 2012, https://www.youtube.com/watch?v=Myn7-_DpSDY. Accessed 14 Mar. 2023.

“Virgin Pulp and Recycled Pulp.” PaperTR, 26 May 2021, https://www.papertr.com/virgin-pulp-and-recycled-pulp/.

“Understanding Tetra Pak Packaging.” YouTube, Nestlé Caribbean, 26 Apr. 2017, https://www.youtube.com/watch?v=WM5d6F6U-i4. Accessed 15 Mar. 2023.

“You Use It Daily. but What Is Polyethylene Plastic?” Reliance Foundry Co. Ltd, 10 Sept. 2021, https://www.reliance-foundry.com/blog/polyethylene-plastic.