As a major step towards the goal of using fully sustainable materials in all its products by 2030, Lego has announced that by the end of 2018, under 2% of Lego bricks will be made from sugarcane-based polyethylene as opposed to oil-based plastic.

As published in Science in 2015, 8 million metric tons of plastic enter the oceans as waste each year. By the end of 2025, the estimated cumulative plastic in the ocean will be approximately 160 million metric tons, which is 100 bags of plastic per foot of coastline around the world. In a major step forward toward the use of sustainable plastics in the consumer goods sector, approximately 25 different Lego shapes, most of them representing plants, will now be made from sugarcane-based polyethylene as opposed to oil-based plastic. By the end of 2018, under two percent of Lego bricks will contain the new polyethylene; this is the first step toward Lego’s ultimate goal of using fully sustainable materials in its products by 2030.

What are bioplastics?

Bioplastics, according to the Society of the Plastics Industry (SPI) Bioplastics Council, are defined as  plastics that are biodegradable, contain biobased content, or both. When a plastic is biodegradable, the plastic completely breaks down at the molecular level, returning the carbon in the plastic to the earth’s natural carbon cycle. The term, biodegradable is different from biobased. Petroleum-based plastics can be biodegradable; moreover, biobased plastics, plastics made from intermediates that originate in living organisms, may not be biodegradable.

In addition to polyethylene, various processes for developing bioplastics are in the pilot plant phase, such as PHA and intermediates for polyesters, and they are becoming cost competitive.  However, for companies looking for an immediate sustainable solution that doesn’t require intensive process changes, “drop-in” degradable additives are a possible solution.

Drop-in degradable polymer additives: What are they and why are they attractive?

Drop-in additives are attractive because they can simply be added to the existing manufacturing process, typically at the same stage that a colorant may be added. After use, the plastics biodegrade from the action of naturally occurring microorganisms, such as bacteria, fungi and algae. This degradation can be initiated by oxygen, ultra violet light or heat. Biodegradation can occur in either aerobic (with oxygen) or anaerobic (without oxygen) environments. As such, biodegradable additives fall under two categories: oxo-biodegradables and non-oxo-biodegradables.

• Oxo-biodegradable plastics fragment and partially biodegrade to CO2 and water in parts of the landfill where oxygen is present; however, degradation cannot continue deeper in the landfill in the absence of oxygen. These additives are more ideal for composting the plastics in high-moisture, oxygen-rich environments, and the plastics are typically not recyclable. Typically, oxo-biodegradable additives can contain metal salts that cause the plastic to fragment, polluting the ground and water.
• Non-oxo-biodegradable plastics operate by promoting the microbial degradation of plastics in anaerobic landfill environments. These plastics typically remain recyclable.

Some examples of companies providing both types of additives are provided below.

Companies that provide biodegradable additives:

Nordic Ecoflex

ECOFLEX–M is a non-toxic oxo-biodegradable additive that does not contain heavy metals. It is currently used in food contact applications (plastic trays, coffee cups, plastic bags, stretch film, film for food packaging and other products used to package food) worldwide. The additive works well with all PE and PP resins, and 1-2% loading is required. They claim that the resulting plastics are recyclable.

Wells Plastics

Reverte is a group of a non-toxic oxo-biodegradable additives that does not contain heavy metals. Reverte is well suited for a wide range of processes and applications and has extensive food contact approvals. Their additives are currently applied to plastic bags, agricultural mulch films and flexible films and laminates. Wells Plastics is a founding member of the OBPF and an active lead player in ASTM D20.96 which is concerned with plastics that are designed to degrade in the environment.

Breakdown Plastic

These plastics are designed to be ‘landfill-friendly’, biodegrading in an anaerobic landfill environment. These organic additives accelerate the degradation of plastic through microbial activity. Breakdown Plastic products are not compostable. Plastics with Breakdown additives can can be tossed in the recycling bin, and if trashed, they will biodegrade in the landfill, which is a much better solution. The required loading is ~1% by weight.

Biosphere Plastic

They develop biodegradable additives that rely on enzymatic degradation. Their unique plastic additives enhance the biodegradability of base polymers such as PP, PE, PS, PET and other major resin types. When BioSphere first released their product in 2012, their additive was only available as a solid. Since then, BioSphere has developed a liquid and powder formulation and a compostable additive should pass the ASTM D6400 testing standard for compostable plastic in the United States.

Are these additives effective?

A number of companies that use plastic packaging have looked at using additives that claim to cause normally non-biodegradable plastics to biodegrade or to accelerate their biodegradation. But are these additives effective? Professor Susan Selke at Michigan State University (MSU) completed a study in 2015 in which her team evaluated the performance of three commercial biodegradation-promoting additives for plastics: Reverte for PE, Eco-one EL 10, and d2w. Unfortunately, “There were no significant differences between the samples with and without the additives, and no evidence of substantial biodegradation of any of the samples.”

Since then, Adelene Ong, Technical Director for EPI Environmental Plastics Inc., wrote a rebuttal statement to MSU’s findings, noting that the study “was found to contain a number of methodological flaws and scientific inconsistencies.” In 2017, The Institute of Scrap Recycling Industries (ISRI; Washington, DC) posted the following policy positions regarding the utilization of biodegradable additives:

• “Any use of ‘bio-degradable,’ ‘oxo-degradable,’ ‘photo-degradable’ or other terms that indicate the plastic is easily degraded be supported by independent third-party research and testing using accepted standard methods and specifications published by ASTM, ISO or other standard-making bodies;
• the introduction of products that contain degradable additives do not harm or compromise currently acceptable recycling practices, recycled material product expectations and the affiliated recycling infrastructure; and
• that such additives do not encourage or excuse poor consumer behavior such as littering.”

What does Lego think?

To gain further insight into the current adoption of sustainable polymers within the consumer goods industry, PreScouter interviewed René Mikkelsen, Sr. Material Platform Manager at Lego:

Q: Would Lego consider using “drop-in” additives, such as oxo-biodegradable or anaerobic enzymatic degradation additives, as an alternative to using biobased plastics?

A: Our ambition is to go for durable polymers. The oxo-process is typically associated with a lot of negative side effects, and this process is not in scope for us.

Q: What is your opinion about the current state of “drop-in” additives that encourage polymer degradation after use?

A: Overall, we prefer durable polymers. An alternative could be a degradable polymer that is compostable through industrial scale composting.

Q: Can you provide examples of other consumer goods that currently embrace the use of plant-based polyethylene?

A: The Finnish toy company Plasto launched a product line in plant-based PE in the spring of 2017. More can be found at http://www.braskem.com/site.aspx/Partnerships

Q: What is your opinion overall about the state of sustainable plastics technologies in the consumer goods vertical? Are the costs becoming comparable, or is the tech still in the pilot testing phase?

A: There is still a premium price on bio-plastics, but we see a lot of emerging and competing technologies. In addition, we see a lot of movement in the area of recycled plastics and we expect this to grow significantly in the coming years. Overall, the consumers are becoming more and more aware of bio-plastics and recycled plastics, but these are still challenging topics to communicate to most consumers.

Final thoughts:

Do you want your product line to remain recyclable or to become compostable in a landfill? Should you incorporate a drop-in additive, or can a bio-based polymer achieve the same performance criteria in your product line? Ultimately, energy- and cost-effective biobased polymers will provide the best benefit to reducing the impact of plastic goods on the environment. Until the ideal incentives and technologies are in place for your product line, the appropriate additive can provide a short term sustainable solution.

With the growing number of environmentally conscious consumers, sustainability is becoming increasingly necessary for companies worldwide. Wondering how your company can achieve this goal in the most cost-effective way without compromising quality? Our team of expert researchers can help. Contact us today!