The rapid adoption of plastics in innumerable applications over the years stems from their overall benefits versus other materials; in particular, their reliability, ease of manufacturing, lighter weight and affordability. However, with heightened awareness about limited energy resources and environmental concerns, plastic products from conventional sources such as natural gas and oil are sometimes perceived by the public and decision makers alike as having negative impacts on sustainability.
In fact, today’s plastics offer many benefits versus alternative materials and much is being done to further address sustainability within the plastics industry. Today’s plastics users are demanding products that reduce environmental impact while improving performance, functionality and value. Increasingly, they expect sustainability benefits to extend across a product's life cycle, from raw material sourcing and manufacturing to final consumption and disposal. This is consistent with ExxonMobil Chemical Company’s long-held approach to energy efficiency and focus on improving the contribution of its products to all sustainability pillars. These improvements have come from improving today’s plastic products, as well as from new innovations.
In packaging, the developments of new metallocene polyethylene products (mPE), such as ExceedTM and EnableTM mPE resins from ExxonMobil Chemical, continue to play an important role in reducing resource consumption and packaging weight while providing enhanced performance and packaging design and aesthetics. Over the past two decades, packaging film thickness in applications such as heavy duty sacks has been continuously decreasing from about 200 microns down to less than 100 microns, as shown in Figure 1 below, while providing the same user benefit. These improvements are the result of innovations in mPE products, conversion equipment and applications technology development. The journey continues and further reductions in film thickness down to 80 microns and lower are on the horizon as new mPE materials are invented and conversion processes developed. This is a strong example of how plastics packaging can contribute to sustainability by playing its important role of protecting products — keeping them fresh, preventing leakage and tampering, and increasing shelf-life while minimizing resources use and emissions.
As sustainability concerns continue to gather momentum, companies are expected to do more than develop and manufacture better products —they need to help create a market for them. This means demonstrating to customers and decision makers how these products save energy, reduce raw material use and mitigate environmental impacts. This is achieved through deep technical understanding in product development and the adoption of a life cycle thinking approach by using Life Cycle Assessment (LCA) to evaluate potential environmental impacts. LCA allows both a holistic view and quantification of the environmental impacts associated with a product or activity over its entire life cycle and avoids burden shifting.
LCA Case Study
Recently, ExxonMobil Chemical Company carried out an LCA of heavy duty sacks in collaboration with one of its customers, Nordfolien GmbH. The sacks are made with ExxonMobil Chemical’s ExceedTM and EnableTM mPE resins and are used for packaging powdered construction products, such as cement premix[i]. The analysis, conducted in accordance with ISO 14040 and 14044:2006 LCA guidelines, evaluated the environmental profile of 25 kilogram (55 pound) heavy duty sacks compared with conventional solutions of three-layer paper/PE/paper structures. Six paper sacks and five PE heavy duty sacks were assessed. The LCA results demonstrate that mPE film heavy duty sacks have several lower environmental impacts when compared to paper sacks. These advantages become more significant when packaging damage and product loss are considered. Based on the experience of Nordfolien customers, a five percent cement loss rate caused by damage to the paper packaging structure is not uncommon. mPE heavy duty sacks deliver the following primary benefits:
- mPE film sacks are lighter than their paper counterparts, resulting in less use of resources and lower transportation emissions.
- Currently, a heavy duty sack made with mPE resins typically weighs 65 grams, while a paper equivalent is 83 grams or more. New technology is also enabling the thickness and weight of PE film structures to be driven lower, while strength is maintained or even improved.
- Cumulative Energy Demand (cradle-to-grave) of mPE film sacks is only 39-54 percent that of paper sacks (61-96 percent when there is no package damage and zero product loss)
- Total greenhouse gas (GHG) emissions of mPE film sacks are about 22-25 percent those of paper sacks (85-150 percent when there is no package damage and zero product loss)
By reducing sack weight, energy demand and GHG emissions, mPE heavy duty sacks offer a more robust sustainable solution than conventional paper structures. As a result, mPE films for heavy duty sacks are gaining traction in the marketplace, especially in the do-it-yourself market.
The above LCA example is one case of many demonstrating the potential sustainability benefits of plastics packaging through the reductions of environmental impacts. According to a widely accepted report by PlasticsEurope[ii], if other materials (such as aluminum, glass, corrugated board, paper, etc.) replaced all the plastic packaging in Europe, the respective packaging mass would on average increase by a factor of 3.6, from 18.4 million t/a to 66 million t/a. Life cycle energy demand would increase by a factor of 2.2, from 1,010 million GJ/a to 2,250 million GJ/a and GHG emissions would increase by a factor of 2.7, from 36.6 million t/a to 97.4 million t/a.
In short, there is a large body of evidence supporting the benefits plastics can bring to sustainability. The challenge is for both the chemical industry and consumers to ensure the already established trend of doing more with less continues well into the future. This can be achieved through efficient use of resources, collaboration between all value chain partners, and greater recycling and recovery.