Sustainable Packaging Materials (eBook)

Making Decisions on Your Next Packaging MaterialAs a chief technology officer (CTO), manager, R&D leader, or product developer, you need to make strategic decisions when it comes to sustainable packaging materials. For example, one of the most important decisions is whether to stick with the existing packaging material or switch to a new one. This decision is always a tough one, especially when you must choose between paper and plastics. My goal is to help you make informed decisions. Towards the end of this chapter, I present a decision-aid table for choosing your next packaging material.

For packaging applications, materials such as glass, metals, paper, and plastics are available to choose from. These materials have their own strengths and weaknesses and most of us are aware of these. The question then arises, how does one choose the right material to ensure that a new type of packaging complies with incoming regulations, while still ensuring that low costs and high performance are retained? The aim of this chapter is to provide an overview of these materials, and to help identify where these materials fit into the big picture of sustainable packaging and thus enable decision makers to make the right choices.

Introduction and Uses

Glass is one of the oldest packaging materials, and is made from abundant and naturally occurring materials – sand, soda ash, and limestone. Consequently, glass is regarded as environmentally friendly material, and it is also completely recyclable. In fact, glass can be recycled for an unlimited number of cycles. In addition, glass offers some excellent properties that are important for packaging. For example, it can be used to store wine for several years without spoilage. A great aspect of glass is it does not create microplastics, just like metal and paper packaging.1

Glass is widely used for pharma applications for its excellent inertness, gas and water barrier properties, and optical clarity. However, glass becomes fragile at very low temperature such as −20°°C and thus glass applications in packaging for deep-freeze applications are limited.

Glass Applications in Packaging

Glass was once the king of packaging materials. Currently, glass is used as bottles, jars, glass, vials, pharmaceutical containers, vaccine vials, and other applications (Figure 2.1). Glass has a higher packaging cost and thus is more suitable for medium-to-high value products, such as wine and pharmaceuticals, than for lower value products that cannot support its higher price.

Challenges

Glass requires high temperatures both for initial production and recycling. In addition, glass is heavy and consequently glass is more energy intensive as compared to metal and plastics. Moreover, glass is brittle and thus thicker glass packaging is often used to prevent breakage, but this increases the weight, which in turn leads to higher transportation costs. To prevent glass bottles from hitting each other and breaking during transport and storage, void spaces may be needed between glass items, thus adding to volume/space requirements. Glass is especially unsuitable for e-commerce because of its fragile nature. As compared to paper, plastics, and metals, glass has the worst climate indicators. For example, glass bottles have a larger CO2 emission footprint during manufacturing and transportation than plastic bottles [32].

According to the EPA, in 2018, 12.3 million tons of glass was produced in the United States, accounting for 4.2% of the U.S.’s total MSW generation for that year [33]. In other words, from this total, 3.06 million tons was successfully recycled, with the remaining 9.19 million tons landfilled. Glass used as packaging containers and bottles made 9.79 million tons of contribution to the MSW being generated. Of this packaging glass waste, 3.04 million tons was recycled, and the remaining 6.75 million tons was sent to landfills. So, what about glass beverage bottles? This section of glass contributed 6.5 million tons to MSW, where 39.5% was recycled by recycling 2.5 million tons.

In the EU, the glass recycling rate is 80% [34], which is more than double the U.S. glass recycling rate, which is 32.8%. According to the Glass Packaging Institute, the production of new glass containers from recycled glass offers up to 30% in energy savings and cuts down CO2 emissions by half, thanks to the low melting temperature of the glass and high output [35].

Some key challenges that impede glass recycling rates in the U.S. include single-stream collection, few MRFs, and fewer recycling glass processers. Single-stream collection is not a suitable route for glass recovery as it contaminates the whole recycling stream when it breaks. Because of this issue, most MRFs do not want glass in their recyclables stream. Therefore, a separate collection stream will be helpful for glass recycling, where glass is collected separately, which is widely practiced in the EU.

Glass recycling rates can be increased by introducing multi-stream collection in the U.S. Multi-stream collection is commonly practiced in Europe, but this approach is yet to be adopted widely in the U.S. With the implementation of EPR laws, multi-stream collection is likely to be adopted. While some may argue in favor of single-stream collection, in reality, for glass, the recovery rate is only 40% in single-stream collection and 90% in multi-stream collection [36]. Another challenge encountered with glass recycling in the U.S. is that there are not many MRFs in the U.S. (~350) as compared to over 33,000 in the EU. This is one of the reasons that heavy recyclables like glass become more economical when they are sorted at a nearby MRF rather than shipped long-distance. It should be noted that although glass is a single-type material, the differently colored glass needs to be sorted by color, which adds further cost into recycling [37]. Mixed colored glasses are often used for fiberglass or as fillers in concrete.

Future of Glass as a Packaging Material

Glass bottles are recyclable without loss of quality. In the U.S., one-third of packaging glass is recycled. In some EU countries, the glass recycling rate approaches 95%. Thus, glass is recyclable and has a lower environmental footprint when recycled compared to making virgin raw materials. Glass will continue to be used in packaging, although its use will likely become more focused toward luxury brands or high-value products like wines, medicines, vaccines, etc.

Introduction and Uses

Both aluminum and steel are widely used in consumer packaging, with the most common examples being beverage and food cans. Aluminum is also used as foil as well as in metallized film. Like glass, aluminum and steel are inert in nature and have excellent gas and water vapor barrier properties, thus making them suitable for many packaging applications. As already discussed, sometimes metals are combined with other packaging materials, such as in aseptic cartons made from aluminum foil, plastic, and paper. The metal layer is typically used to provide excellent barrier properties, especially to light and oxygen, thereby enabling long-term shelf-stability for goods such as milk, potato chips, and other sensitive products.

In 2018, within the United States, the total Municipal Solid Waste (MSW) consisted of 3.9 million tons of Al products. From this total, 0.67 million tons were successfully recycled, with the remaining 3.2 million tons landfilled. Al used as packaging material had 1.9 million tons of contribution to the MSW being generated. Of this packaging, 0.62 million tons was recycled, and the remaining 1.25 million tons was sent to landfills. So, what about Al cans for beverages? This section of Al contributed 1.3 million tons to MSW, where 0.66 million tons was recycled at 50% recycling rate.

Applications

Food and beverage cans and some flexible packaging contain metal and metal-bearing multilayers. Metallic packaging is also used for the packaging of pharmaceuticals as well as products such as cans for vegetables, fruit, soups, canned meat, etc. (Figure 2.2).

Aluminum and Ferrous Metals in Rigid Packaging

Because metallic cans are recyclable [38], metals are more likely to meet the recycling mandates. New recycling mandates in the EU and other regions are favoring metal cans resulting in the replacement of polyethylene terephthalate (PET) and other plastics. Metal cans may also replace water bottles. Nearly 75% of new beverages (both alcoholic and non-alcoholic) are now being launched in metallic cans, which is likely due to supply chain considerations as well as producers’ strategic decisions to move to metals [39]. While metals are better than glass in terms of their environmental footprint, a recent life-cycle assessment (LCA) comparison of PET with aluminum cans [40] shows that PET has favorable indicators such as 74% less global warming potential than cans. On the other hand, there are no microplastic concerns arising from metallic packaging and aluminum/metal cans offer better barrier...