New biomaterial technology trends that emphasize sustainability are advancing rapidly across the bioplastics supply chain. Let's take a look at some emerging bioplastic feedstock, material and application highlights from among other sources, the recent 2018 European Biopolymer Summit and World Bio Markets conferences.

Feedstock developments

The recent five-year decline of crude oil prices has hampered the growth of bioplastics, yet the remarkable technology achievements in biochemical building blocks of the past two decades will continue during this transition period, particularly in the packaging market.

Bioplastic companies continue to demonstrate the same technical marketing business ingenuity they have exhibited over the past 25 years by specialty feedstock/resin niche market development, holding in place their existing technology, further focusing on added production efficiencies, and in some limited cases withdrawing from the bioplastic market segment as a result of noncompetitiveness. Let's review some recent bioplastic feedstock developments.

Braskem is the only global supplier of bio-polyethylene based on sugarcane, with 200 kilotons per year plant in Rio do Sul, Brazil. Sugar feedstock has exhibited a low-but-stable price, despite lower ethanol prices as a result of low crude oil prices. Bio-polyethylene market prices average 40 percent higher than standard fossil fuel-based polyethylene. Braskem has put on hold its sugar cane-based bio-polypropylene program until crude oil to ethanol pricing improves.

In the biopolyester segment, bio-polybutylene succinate (PBS), bio-polytrimethylene terephthalate (PTT) and bio-polyethylene terephthalate (PET) are based on a range of renewable content feedstocks such as bio-diacids (succinic acid) and bio-diols (ethylene glycol, 1,3 propanediol). BioAmber has brought on line 30 kilotons per year plant in Sarnia (Ontario) Canada, the largest in the world. Other succinic acid producers include U.S.-based Myriant (14 kilotons), Italy-based Riverdia (10 kilotons) and Spain-based Succinity (10 kilotons).

Thailand-based PTTMCC Biochem will take 15 kilotons per year of succinic acid from BioAmber and react it with 1,4 butanediol at its 20 kilotons per year bio-PBS plant. Coca-Cola's renewable content bottle program continues to grow slowly due mainly to low crude oil prices and high priced monoethylene glycol (MEG) monomer and bio-PET polymer materials.

Sugar cane-derived MEG is produced by only two global suppliers, namely Greencol Taiwan Corporation and India Glycols. Italy's M&G Chemicals is developing a China-based bio-MEG and bio-ethanol facility. India's JBF Industries is considering a bio-MEG plant in South Carolina, potentially working with Coca-Cola.

Renewable feedstocks (left) in relation to conventional petrochemical routes (right). (Image: Plastics Institute of America)

Material advances

Petrochemical-based materials make up the majority of plastics produced, or 325 million metric tons of plastics produced worldwide in 2017. Global bioplastics production capacity will have grown at a compounded annual growth rate of almost 20 percent from 2013 to 2020. Growing from around 5.1 million metric tons in 2013, the production capacity for bioplastics will have increased to a predicted 17 million metric tons by 2020.

By far the strongest growth will be in the bio-based nonbiodegradable plastics group. Bio-based drop-ins, led by bio-PET and the new polymers polylactic acid (PLA) and polyhydroxy alkanoate (PHA), will show the fastest rates of market growth.

Bio-based PET production capacity was around 600,000 metric tons in 2013 and is projected to reach about 7 million metric tons by 2020. Drop-in bioplastics, such as bio-based PET and bio-based polyethylene (PE), are chemically identical to petroleum-derived plastics and are rapidly gaining acceptance. The use of these drop-in materials involves much less risk versus unknown novel materials and is compatible with existing recycling streams.

Bio-based PET production is expanding at high rates worldwide, largely due to the Plant PET Technology Collaborative (PTC) initiative launched by the Coca-Cola Company. Other drop-ins that have been or are being commercialized include bio-based nylon, polypropylene, polystyrene, polycarbonate, polyvinyl chloride and many other traditional plastics.

The second-most dynamic development is foreseen for the family of biopolymers, known as PHA, PLA and bio-based polyurethane (PUR), are also showing impressive growth. Their production capacities will have quadrupled between 2013 and 2020. Most investment in new bio-based polymer capacities will take place in Asia because of better access to feedstock and a favorable political framework.

There is a novel commercialized high-performance PLA polymer blend. PLA can be alloyed with other polymers to improve properties including both impact resistance and thermal performance.

Floreon is a fully compostable PLA-polyester-based blend. Floreon Transforming Packaging Ltd. developed the innovative bioplastic. The patented polymer compound yields PLA blends suitable for thermoformed and injection molded packaging that also shows promise for film and blow molding operations. Floreon also works well for 3-D printing.

Floreon PLA/polyester blend based packaging, blowmolded (left), thermoformed (right). (Image: Floreon)

A typical formulation is 90 percent PLA plus 5 percent polyester 1 and 5 percent polyester 2. The additives are completely degradable, certified to EN13432 and suitable for food contact. They serve as a toughening component and a flow rate enhancing component that makes it easier to process.

The additives interact to disperse throughout the material, forming a unique polymer-polymer "nanocomposite" structure. The dispersed spheres deflect stresses and energy in the finished product with minimal effect on clarity.

Continuing, in the biocomposites development field there is an award-winning flax-reinforced composite: Flaxpreg was recently awarded the JEC Europe Innovation Award in the semi-products category.

Flaxpreg is a green, light, very long flax fiber reinforced acrylic composite sandwich structure developed by Faurecia with PSA Peugeot-Citröen, Lineo and the University of Reims Champagne-Ardenne (France). The project, to design structural trim parts, followed three key objectives:

  • a drastic weight reduction
  • the use of renewable resources
  • a process in line with automotive cycle times and material costs constraints meeting the requirements of automotive mass production

The use of unidirectional long nonwoven flax fibers as reinforcement is the key innovation allowing a drastic weight reduction.

The material's low density of 1.45 with an adaptive 0°/90°/0° orientation of the FlaxTapes depending on the loading boundary conditions result in excellent mechanical properties allowing a 35 percent weight reduction compared to petro-sourced glass mat/PUR (PolyURethane) sandwich solutions.

The vibro-acoustic damping properties of the FlaxTape skins are also excellent with a damping loss factor close to 2 percent. Flaxpreg can be applied by automakers as a multiposition trunk load floor or a structural floor in the passenger compartment of a vehicle. Other applications such as package trays, door trims and seat backrests are under investigation.

Flaxpreg acrylic impregnated fiber tape (left), sandwich composite structure (right). (Image: Lineo)

Application trends

The global plastics industry continues to grow due to lower oil prices, and in turn lower fossil fuel-based plastic feedstock costs. Oil and natural gas-based feedstocks will act as a bridge to mid-21st century end-use plastic application development, allowing renewable chemicals to fully mature and give way to bioplastic-focused brand owners and green manufacturers.

Future generations in the form of millennials and Gen Xers are already pressuring their governments globally to reduce dependence on oil for environmental and health reasons. Bioplastic application development will be further enhanced by hard data-driven life cycle analysis extolling the virtues of biopolymers.

Sustainability will continue to be a major theme and will define a new paradigm where the needs of the present generation are met without compromising future generations from meeting their needs. Sustainability on these terms extends well beyond just renewability and includes the whole energy cost of production.

For example, for a bioplastic application derived from corn, it will come down to a full accounting for all the energy and related environmental effects in fertilizer production, corn cultivation and harvesting, transporting these ingredients, and finally all the conversion steps to a bioplastic. Bioplastic application development will adhere to the same economic, cost performance, and supply and demand standards as fossil fuel-based plastic applications.

At present, governments and large plastic end-users are articulating renewability policies. Take Japan as an example. The Japanese government has as the goal of its in-place Biomass Nippon Strategy that 20 percent of all plastics consumed in Japan by 2020 are sourced renewably, which translates into 8 billion pounds of plastic annually. In turn, automotive supplier Toyota is targeting 800 million pounds renewably sourced by 2020, part of which is 200 million pounds per year of PLA for interior trim parts for cars and trucks.

Invercote bio substrate paperboard berry package. (Image: Iggesund)

Next, of interest in bio-based disposable application development, there is new packaging based on an Invercote Bio substrate. Coop, a Swedish retail chain, has selected Iggesund Paperboard's Invercote Bio substrate as the base material for new packaging for its own-brand frozen berries.

Invercote Bio is a virgin fiber-based board coated with bioplastic, which makes the packaging compostable, so that the used packaging can go into the same waste stream as any remaining contents. The bioplastic coating used with Invercote Bio is the bioplastic Mater-Bi from Novamont.

The berry package was developed by the printers Trosa Tryckeri in collaboration with the berry supplier Olle Svenssons Partiaffär. The bioplastic coating posed a challenge with regard to adhesive choice. The difficulty was to find a heat-setting adhesive that functions well technically during production while also withstanding the tough environment it is exposed to in freezers.

Finally, there is a unique PLA/PHA blend filament for use in 3-D printing. The 3-D printing filament developed by ColorFabb using a blend of PLA/PHA results in a tougher and less brittle PLA filament.

PHA co-polymers comprise 3-hydroxy-butyrate (3HB) and other 3-hydroxy-alkanoate (3HA) units with side groups greater than or equal to three carbon units. Incorporation of 3HA units with medium-chain-length side groups effectively lowers the crystallinity. The reduced crystallinity provides the ductility and toughness for the filament.

When a small amount of ductile PHA is blended with PLA, a new type of polymer alloy with much improved properties is created. The toughness of PLA is substantially increased without a reduction in the optical clarity of the blend.

The synergy between the two materials is attributed to the retardation of crystallization of PHA copolymers finely dispersed in PLA matrix as discrete domains.

PLA/PHA blend 3-D printable bioplastic filament. (Image: colorFabb)