An alternative to recycled material?
By Callum Colford, Miranda Zhang, Heng Hui, Abdulaziz Ehtaiba
Bioplastics can refer to plastics that are bio-based, biodegradable or both, with bio-based polymers those that are produced from a bio-based feedstock.
To produce one metric ton of bio-polyethylene requires 33.55 mt of sugarcane, 27.26 mt of sugar beet, 27.5 mt of potato, 10.76 mt of wheat or 7.07 mt of corn, according to the Institute of Bioplastics and Biocomposites.
In practical market applications, consumers may choose to utilize the mass-balance “drop in” approach, in which they combine bio-based material with traditional fossil-based material, producing an end-product that consists of typically 30-50% bio-based material.
Though no classification has been agreed globally regarding minimum bio-based values, the Japanese BioPlastics Association and US Department of Agriculture require a minimum of 25% bio-material to qualify for their bio-based certification.
Bio-based production of “traditional” polymers such as polyethylene, polypropylene or polyethylene terephthalate typically utilizes production of material via the drop-in method, substituting a fossil-based feedstock for one that is bio-based while producing material that has the same physical properties as the “traditional” alternative.
Polylactic acid (PLA), a biodegradable plastic made from bio-based feedstocks, is the largest bio-plastic in terms of global production capacity and PLA capacity expansion is set to continue after the two leading PLA producers, Natureworks, a Cargill and PTT Global Chemical joint venture, and Total Corbion PLA, a joint venture between Corbion and TotalEnergies, both announced plans to bring new production online in 2024.
Natureworks is to build a 75,000 mt/year PLA production facility in Thailand, while Total Corbion PLA aims to have a 100,000 mt/year PLA plant operating at Total’s Grandpuits site in France by 2024.
PLA can be used in packaging, in 3D printing and as a replacement fiber in teabags. PLA is already used by brands such as Yorkshire Tea and in food packaging at tourist attractions such as the Royal Botanic Gardens at Kew in London.
While biodegradable materials such as PLA or polyhydroxyalkanoates (PHA) may have different or even improved properties compared with the range of fossil-based polymers that they can substitute, their biodegradable properties have been widely viewed as incompatible with current mechanical recycling, which may be a limiting factor on their application moving forward.
“PLA has some tough challenges to [overcome] before finding its way in the circular model and that is the problem with bio-segregated material – if you want to move to a new type of polymer or chemistry then you will have to develop the associated recycling schemes,” one market source said.
Bio-based non-biodegradable materials which have a clear fossil-based equivalent with an already developed recycling stream do not face these additional hurdles.
Companies have noted the incompatibility of biodegradable material with recycling schemes and significant time periods that some biodegradable material takes to biodegrade led them to focus on other production methods. For example, Borealis has said it has no intention of producing biodegradable plastics as “we believe recycling as an end-of-life option is better sustaining the value in the plastic and we do not want to risk the littering of plastics due to biodegradable claims… Producing bio-based plastics from renewable feedstock, on the other hand, is a real opportunity for us to reduce the carbon footprint of our products and decouple plastic production from fossil-based feedstock.”
According to the European Bioplastics industry body, global bio-based polymer production capacity is expected to grow from 884,000 mt/year in 2020 to 1,081,000 mt/year in 2024 with bioplastic production estimated to be around 1% of total global polymer production annually. However, the share that bio-based material encompasses in the bioplastics market has declined in recent years as volumes of biodegradable material grow at a faster rate.
Bio-based polyethylene is the most-utilized and commercialized product in the bio-based sector, according to the body, representing around a quarter of bio-based, non-biodegradable polymers produced.
Consumption patterns were dominated by the packaging sector, consuming some 46% of bio-based production, according to European Bioplastics.
The commercialization of bio-polypropylene production has been more limited when compared to products such as bio-PE. Production routes for bio-PP have been developed by companies such as Braskem, LyondellBasell and Borealis, but details remain largely confidential.
European Bioplastics expects bio-based PP use to more than quadruple over 2019 to 2025 due to a wide range of downstream PP applications.
Although bio-based polymers should, in theory, work hand-in-hand with the recycled material, market sources said that perception among the public and brand owners meant that bio-based options were being sidelined in favor of recycled material.
“Bio will have its place but if you say today to a customer do you want recycled or bio-PS, the customer says recycled as it chimes [better] with the circularity theme,” a styrenics producer said.
Limited availability and the significant cost barrier remain major impediments to bio-based material being more widely adopted by the market despite its identical properties, according to industry sources.
In Asia, bio-based polymers, though still at much more of a preliminary development stage than in Europe, are increasingly seen as a way of complementing existing recycling solutions to control plastic pollution.
Market participants expect China to lead demand growth for biodegradable plastics in the coming years after China announced stringent plastics control and bans for single-use non-degradable plastics in 2020. The focus in China is expected to be on “degradable” plastics rather than bio-based polyolefins.
The value of China’s biodegradable plastics market will hit around Yuan 35.8-47.7 billion ($5.5-$7.4 billion) by 2025, with demand exceeding 2 million mt/year, according to estimates by China’s Huaxi Securities and HuaAn Securities.
Most of the demand comes from disposable food container and utensils, packaging for express delivery, single-use plastic bags and agricultural films.
Biodegradable products such as PLA and polybutylene adipate terephthalate (PBAT) are two of the fastest growing bio-plastic markets in China, receiving the most interest from end-users in the country.
At least 330,000 mt/year of new PLA and 120,000 mt/year of new PBAT capacity is expected to be brought online in China in the second half of 2021 to early 2022, according to annual reports and announcements by leading manufacturers in China, with more new projects expected in China in 2022 and 2023.
Despite the largely optimistic outlook for biodegradable plastics growth in China, there are concerns about the economic competitiveness of biodegradable plastics, which are priced much higher than conventional plastics.
Aside from biodegradable material, bio-based output is largely limited to Japan, where Mitsui signed an agreement with Neste to purchase bio-naphtha for its steam cracker located at Osaka, becoming the first company to produce renewable polymers on an industrial scale in the country.
For the time being, sources said neither biodegradable plastics nor bio-based polymers were immediately available in mass quantities with most schemes remaining at a pilot stage, and mechanical recycling of fossil fuel-based polymers still more prevalent in Asia.
