A 100% bio-based PET PlantBottle shows there’s growth in bioplastics applications, even in a world of low oil prices (photo courtesy of Coca-Cola Co.).

Successful mass-market applications of biopolymers aren’t easy. Some applications took 10-15 years to develop in successive tries and material stages. Biopolymer applications don’t automatically win applause from environmental groups, which may have their own agendas. The largest biopolymer user in the world had to create its own. And all bioplastics at least initially cost a lot more than conventional plastics, so there’s real risk to a big brand.

Why do companies go through all that? Here’s a look at four large and successful applications of biopolymers and at what companies went through to get there: compostable starch polymer films and bags, form-fill-seal PLA yogurt containers, bio-content PET bottles, and bio-polyethylene films. All the companies took the plunge when their biopolymer of choice was either not available yet or very new. They are all poised now to bring new biopolymer technologies to market.

The latest development for biopolymers is a high-strength bio-polyester made from thistle seed oil at the Novamont Matrica biorefinery in Sardinia. Thistle seed oil is refined into bio-azelaic acid, then combined with bio-butanediol and petro-terephthalic acid to make the new polyester. (Photo courtesy of Novamont.)

Progress Since 1990

The two original mass-market biopolymers sprouted in the early 1990s, challenging polyethylene with bio-content and biodegradability.

In 1990 Novamont S.p.A., in Novara, Italy ( www.novamont.com), launched Mater-Bi starch polymer compounds with an 8 million lb/year (3.6 million kg/yr) pilot plant. In 1992, Cargill Inc. of Minnetonka, Minnesota ( www.cargill.com), started a pilot plant for 10 million lb/year (4.5 million kg/yr) of polylactic acid (PLA) biopolyester. Ten years later, Novamont and (Cargill’s PLA venture) NatureWorks LLC ( www.natureworksllc.com) both had over 100 million lb/year (45 million kg/yr) of capacity for their respective bioplastics, and were figuring out how to use them. 

Ten years and an oil crisis later, two major “drop-in” biopolymers appeared. In 2009 Coca-Cola Co. launched its “PlantBottle,” for which Coke introduced 30% bio-content PET. In 2010, Braskem S.A., Sao Paolo, Brazil ( www.braskem.com), started up the world’s first full-scale bio-PE plant at 440 million lb/year (200 million kg/yr), based on converting bio-ethanol from Brazilian sugar cane first to bio-ethylene and then to bio-PE. (Previously several small plants in Brazil in the 1970s and 1980s used older technology to make bio-ethanol, but these were inefficient and later closed.) Drop-in bio-polymers are chemically just like conventional ones, so their benefit is entirely renewability, and their disadvantage depends on the price of oil.

More Bio in the Bag

BioBag International AS, Askim, Norway ( www.biobagworld.com), is the world’s largest producer of certified compostable bags and films, and the largest user of Novamont’s Mater-Bi compostable polymers. The partnership goes back to 1992 when BioBag co-founder and sales director Jorn Johansen realized that if Norway was going to collect food scraps for composting, they would need compostable bags.

Biobag was one of Novamont’s first customers for Mater-Bi, years before it was commercially available. Starch polymers were originally used to mold gel capsules, not for blown film. Everything about processing early Mater-Bi compounds was difficult, BioBag’s Johansen recalls. The low-temperature material had to be run slowly or it smoked. At the right speed, it smelled slightly sweet, or like popcorn, or had no smell at all, depending on starch content. When BioBag first ran the materials in winter in very dry air, they had so many problems with bubble stability that they humidified the plant. Novamont tweaked the formulation.

By 2002, in addition to its own compostable films and bags, BioBag began to develop custom films for customers who wanted compostability for things like thermoformed trays and diapers. (One of Johansen’s more interesting custom assignments was to design collapsible field toilets with compostable bags for the Norwegian army.) Novamont tailored nearly ten grades of Mater-Bi over the years for BioBag’s own and custom films, all certified compostable, but with different properties and rates of decomposition.

Also in 2002, two entrepreneurs started BioGroup USA in Dunedin, Florida ( www.biobagusa.com), to produce BioBag certified compostable bags in the USA, becoming a BioBag subsidiary in 2011. Since 2008, BioBag also makes one-to-three-layer black and white agricultural films with up to 60-inch (1500-mm) bubble diameters.

Over the same time, the renewable content of Mater-Bi compounds grew steadily from up to 25% in the beginning to over 50% now. Novamont’s “third generation” Mater-Bi compounds, being developed now, use a new high-strength bio-polyester based on sunflower seed or thistle seed oil. It’s refined by Matrica S.p.A. in Porto Torres, Sardinia ( www.matrica.com), a 50/50 joint venture between Novamont and Italian petrochemical company ENI/Versalis. Versalis contributed an uncompetitive petro refinery in Porto Torres, which was converted into a biorefinery with capacity for 70 million lb/yr (32 million kg/yr), using Novamont technology to convert vegetable oils to bio-intermediates including azelaic acid. 

Azelaic acid, a dicarboxylic acid, is combined with bio-butanediol and petro-terephthalic acid to make Novamont’s new patent-applied-for bio-content polyester (U.S. Pat. App. 20140106097). Blended into Mater-Bi grades, the new polyester will allow thinner, stronger bags with higher renewable content, Novamont says. Its patent application also describes a secondary cold stretching process, either monoaxial or biaxial, which could make high-renewable-content compostable bags competitive with conventional PE bags. BioBag’s Johansen expects to have “thistle polyester” in BioBag products this year.

BioBag was one of Novamont’s first customers for Mater-Bi starch polymers, when they were still in pilot plant production. Today BioBag is the world’s largest producer of certified compostable agricultural films and bags and also develops compostable films for customers. (Photo courtesy of BioBag.)

PLA Game-Changers?

Meanwhile, Danone AS, headquartered in France ( www.danone.com), is the first company to switch to bioplastic yogurt containers. Globally Danone reportedly has over 5% of its yogurt packaging in PLA, a major achievement.

One of the earliest customers for NatureWorks’ PLA in the mid-1990s, years before PLA was commercial, was Danone Deutschland GmbH in Germany. In January 1998 the company introduced a premium line of yogurt called “Jahreszeit” (“seasons” in German) in egg-shell-colored PLA cups. According to press reports at the time, the cups cost three times as much as PS cups, but were compostable. “Jahreszeit” also had to switch from steam sterilization, which is too hot for PLA, to UV-light sterilization. Danone expected to expand the use of PLA cups, but the concept of yogurt offering flavors only when fruits are in season limited sales, and the brand was cut.

In 2000, Stonyfield Farm Inc. ( www.stonyfield.com), an organic food operation that gives 10% of its profits every year to environmental causes, did initial trials with PLA packaging, but didn’t commercialize it. They also gradually contacted over 50 farming and environmental groups to evaluate PLA, and found them supportive. A decade later, Stonyfield, then 85% owned by Danone in France, worked with ClearLam Packaging Inc., Elk Grove Village, Illinois ( www.clearlam.com), an experienced processor of PLA. 

In six months, ClearLam developed PLA sheet for Stonyfield’s existing form-fill-seal machinery from Arcil S.A. ( www.arcil.fr) and Erca S.A. (now part of IMA Dairy & Food Holding in Germany) in France. PLA has a higher density (1.24 g/cc) than HIPS (1.08 g/cc), but it’s stronger, and its high impact strength allowed successive down-gauging.

The previous HIPS trays were 35-mils (0.89-mm) thick and weighed 4.4% of product weight. By contrast, Stonyfield’s first PLA form-fill-seal packages in 2010 were only 30-mils (0.76-mm) thick. By 2011, PLA had been impact modified and could be down-gauged to only 28 mils (0.71 mm). Stonyfield’s PLA consumption was 1.6 million lb (730,000 kg). By 2012, further PLA improvements allowed down-gauging to 26 mils (0.66 mm) and reduced PLA use to 1.5 million lb (680,000 kg). 

The switch from oil-based HIPS to bio-based PLA became cost-neutral. PLA trays, which started as 4.4% of product weight, were down to only 4.1%. There were also energy savings from lower forming temperatures, and lid adhesion was better, Stonyfield’s Hirshberg reported. “Other benefits include better aroma and gas barrier than HIPS,” NatureWorks adds. Stonyfield buys “GMO offsets”—Working Landscape Certificates from the Institute for Agriculture and Trade Policy ( www.workinglandscapes.org)—to support sustainable corn growing, corresponding to their PLA use.

PLA Resistance, and Advancement

In 2011, a year after Stonyfield’s successful PLA launch in the USA, Danone GmbH ( www.danone.de), switched its Activia yogurt brand to PLA cups in Germany and Switzerland. The switch was planned together with the World Wildlife Fund, whose logo was on the package. Announcements quoted a life-cycle analysis showing an improved carbon footprint and savings in fossil fuels. 

But by 2012 an environmental group, Deutche Umwelthilfe e.V. ( www.duh.de), which opposes disposable packaging, issued a report accusing Activia of “greenwashing” and false claims for “a new environmentally friendly package.” Deutsche Umwelthilfe nit-picked the life-cycle analysis and “lobbied for PS, which could be recycled in Germany,” Danone says. Danone in Germany changed the labels, but kept Activia in PLA. 

Danone in Canada plans to switch its form-fill-seal yogurt trays from PS to PLA this year. Danone has also worked internally since 2011 to develop its own PLA formulations, including foamed form-fill-seal trays being developed with Clariant SE in Muttenz, Switzerland ( www.clariant.com).

In 2012, after 50% of NatureWorks was acquired by PTT Global Chemical PCL in Bangkok, Thailand ( www.pttgcgroup.com), NatureWorks planned a second PLA plant in Thailand in 2015. (Corbion (formerly Corbion Purac Biochem) in Amsterdam, the Netherlands ( www.corbion.com), runs a lactide monomer plant in Thailand based on tapioca.) But with oil prices currently so cheap, NatureWork’s second plant has been delayed.

PLA from non-GM feedstocks is available from three small producers, each with about 10 million lb/yr (4.5 million kg/yr) capacity: Zhejiang Hisun Biomaterials Co. Ltd., Taizhou, Zhejiang, China ( en.hisunplas.com); Jiangsu Supla Bioplastics Co. Ltd., Suqin, Jiangsu, China ( www.supla-bioplastics.cn); and Synbra Technology B.V., Etten-Leur, the Netherlands ( www.synbratechnology.nl).

Meanwhile, PLA technology keeps getting better. A recent patent application from NatureWorks (U.S. Pat. App. 20150087799) describes a new route to higher-property and higher-temperature PLA. It’s built on a non-fermentation chemical route to lactic acids, developed with Nobuyoshi Nomura, a professor of bio-agricultural science at Nagoya University in Japan.

This chemical process results in a 50/50 mixture of D and L lactic acid, which would normally be unusable because the two have to be separated before they can be made into PLA, adding a lot of cost. NatureWorks’ invention is a ring-opening catalyst to make stereoregular, high-temperature PLA copolymers starting with this mix of D and L lactic acids. 

Coke’s 30% bio-PET PlantBottle is the world’s largest biopolymer application—a remarkable feat for a major brand that isn’t “organic.” Heinz licensed and used the PlantBottle, but after Heinz was acquired by Brazilian investors, they cut costs and bio-content PET. (Photo courtesy of Coca-Cola.)

“Drop-In” Biopolymers

The largest single biopolymer application in the world is Coke’s 30% bio-content PET PlantBottle, introduced in 2009. Bio-content now makes up 8% of Coke’s total PET usage, the company says. That’s an astonishing effort for a major brand not associated with being “organic.” Because bio-content PET is chemically identical to oil-based PET, it doesn’t disrupt existing processes or recycling. By 2012, all of Coke’s Dasani water bottles and many Coke bottles globally were in PlantBottles, for a total of about 10 billion bottles. 

By the end of 2015, Coke had distributed nearly 40 billion PlantBottles in all. Conservatively assuming that all 40 billion are only 20 fluid ounces in size (not 1-2 liters), and that a 20-oz. PET bottle weighs 0.84 oz. (24 g), according to NAPCOR (National Assoc. for PET Container Resources), then the 30% bio-content totals about 630 million lb (290 million kg), with stable consumption of close to 100 million lb/yr (45 million kg/yr) of bio-content since 2010. 

PET is made from 32.2 wt% monoethylene glycol (MEG) and 67.8 wt% purified terephthalic acid (PTA), combined in an esterification reactor and converted to polymer in a polycondensation reactor. The bio-part is bio-MEG. To make it, Coke buys bio-ethanol in Brazil and India and ships it to India Glycols Ltd. in Kashipur, India ( www.indiaglycols.com). Bio-MEG is then shipped to over a dozen PET manufacturers around the world, who supply Coke PlantBottles locally in 42 countries.

In 2009, when Coke launched the PlantBottle, India Glycols was the world’s only supplier of bio-MEG, with 440 million lb/yr (200 million kg/yr) of capacity. Since then, in 2013, Greencol Taiwan Corp. started a line with capacity for 165 million lb/yr (75 million kg/yr) of bio-MEG. Greencol also converts Brazilian bio-ethanol from sugar cane into bio-ethylene and then into bio-MEG, which is used in Toyota Tsusho’s Globio-brand of 30% bio-PET. 

Coke says it will expand PlantBottle use when more bio-content PET becomes available, and wants all its products in 30% bio-PlantBottles by 2020. Coke also licensed its PlantBottle to other companies to expand use, including H.J. Heinz Co., Ford Motor Co., and SeaWorld Entertainment Inc.

Heinz had converted 20-oz. ketchup bottles to PlantBottles by 2014 and expected to have 100% bio-PET bottles by 2018. But in 2013, Heinz was acquired by 3G Capital, a large Brazilian investment fund in Rio de Janiero. During cost-cutting after the takeover, Heinz’s PlantBottle program was cancelled.

Coke eventually wants to use 100% bio-PET and showed a 100% bio-PlantBottle at the World Expo in Milan, Italy, in June 2015, but it has not said when 100% bio-PET will be available. PepsiCo also showed a 100% bio-PET bottle in 2011, saying it intended “pilot production” by 2012. But Pepsi gave no information about where the bottle was made, and has announced nothing since, as of this writing.

Read more of author Jan Schut’s comments and research about biopolymers at the Plastics Engineering Blog, particularly the September 2015 posting at www.plasticsengineeringblog.com/2015/09/.

Given low oil prices, it’s hard to know what kind of growth patterns may develop for new biopolymer applications. (Matrica bio-refinery photo courtesy of Novamont.)