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http://mitpress.mit.edu/jie Journal of Industrial Ecology 209

� 2004 by the Massachusetts Instituteof Technology and Yale University

Volume 7, Number 3–4

Cargill Dow LLCPatrick R. Gruber

Cargill Dow, LLC12700 Whitewater DriveMinnetonka, MN 55343�www.cargilldow.com�

Patrick R. Gruber is vice presidentand chief technology officer atCargill Dow LLC.

• Year founded: 1997• Ownership: Joint venture of

Cargill and Dow Chemical• Headquarters: Minnesota, USA• Product category: Polymers• Employees: 200 to 300• Production capacity: More than 300 million pounds of

NatureWorks PLA per year

Cargill Dow LLC, based in Minnetonka, Minnesota, offers afamily of polymers derived entirely from annually renewable re-sources with the cost and performance necessary to compete withtraditional fibers and packaging materials. Founded in 1997, thecompany has achieved this by using a simple process of fermen-tation, distillation, and polymerization to derive a proprietary po-lylactide polymer, NatureWorks�1 PLA,2 from field corn.

Cargill Dow harvests the carbon stored in simple plant sugarswhen corn plants photosynthesize. Initially, the corn grain ismilled, separating starch from the grain. Unrefined dextrose, inturn, is processed from the starch and is turned into lactic acidusing a fermentation process similar to that used by beer producers.Through a condensation process, the cyclic intermediate dimerlactide is formed and then purified through vacuum distillation.Finally, ring-opening polymerization of the lactide is accomplishedwith a solvent-free melt process, delivering PLA resin.3

In April 2002, Cargill Dow LLC opened the world’s first global-scale manufacturing facility capable of making commercial-gradeplastic resins from an annually renewable resource. The facility,which represents nearly $750 million in investments, is capable ofproducing more than 300 million pounds (about 136 million kilo-grams) of NatureWorks PLA per year and using up to 40,000 bush-els (about 1.4 million liters) of corn per day. The resin is beingshipped around the globe for use in producing food and nonfoodpackaging, disposable cups and utensils, comforters, pillows, carpettiles, and apparel.

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The Formation of CargillDow LLC

The development of NatureWorks PLA be-gan as a small-scale project for a team of Cargillscientists asked to explore new uses for corn. Car-gill was looking for ways to expand the use of thebillions of bushels of corn and related by-products flowing through its mills. After evalu-ating opportunities together with professionalsfrom the chemical industry and listening to theadvice that they gave, the team determined thatdesirable, and more sustainable, products wouldneed to (1) work in commercial applications, (2)be economical, (3) be made from renewable re-sources, and (4) have a much smaller environ-mental footprint than conventional products.

Once the team determined the criteria, theythen looked at potential products. As a result ofmarket and technology investigations, the Car-gill team came to believe that it is possible tomeet all of the criteria by combining the best oflarge-scale industrial biotechnology with chem-ical processing. The Cargill team made a list ofpotential products. PLA was on that list.

PLA is not new—Wallace Corothers, the sci-entist who invented nylon, first discovered it inthe 1920s—but it never had been successfullycommercialized on a large scale. PLA cost wasorders of magnitude too high, and its technicalperformance was not acceptable for large-scaleplastics and fibers applications and products.

It made the Cargill team’s list because it fitthe criteria and the Cargill scientists recognizedthat it was possible to solve both the cost andperformance issues. PLA is produced from lacticacid, a naturally occurring product found in ev-erything from yogurt to overexerted muscles.PLA’s monomer, lactic acid, exists in two forms,left-handed and right-handed. To form a poly-mer, monomers are linked together like pearls ona necklace. By controlling the amount of right-and left-handed monomers as well as the chainlength, the properties of PLA can be controlledto meet commercial needs in a wide variety ofapplications. Prior attempts by industry at pro-ducing PLA resulted in a resin that cost $100 perpound, nearly 100 times more than what com-peting polymers command. The Cargill technol-ogy solved the expensive manufacturing issues byavoiding solvents, using simple unit operations,

and designing the process to be highly efficientand very flexible.

The Cargill team recognized that they neededto have a product that would deliver the perfor-mance and price necessary to compete with tra-ditional resins. Anything less would keep PLA inthe category populated with many other “envi-ronmentally friendly” plastics of the time: expen-sive, poor-performing niche products that neverseriously competed with products produced frompetrochemicals.

Cargill worked with various polymer partnersin the period of 1989–1994 but proceeded forthe most part on their own. Attention to PLA’smarket viability was critical in ensuring the teamgot the organic chemistry and plant engineeringright. Too often, in the hopes of creating sustain-able processes, businesses, governments, and en-vironmentalists focus too intensely on the pro-cess and not the product. So, Cargill createdprototypes to do concept tests in the market-place. What they found was a laundry list of re-quirements plastics customers were looking for ina new resin, all of which they believed they coulddeliver with PLA.

In 1994, the company built an 8 millionpound per year PLA facility in Savage, Minne-sota, to produce lactide on a larger scale. Thisplant was then used to perfect the manufacturingtechnology and allow further development of acommercial market for PLA. In early 1995, Car-gill realized it needed a partner with a presencein the polymer market, as it was generallythought that Cargill alone did not have the nec-essary credibility in the plastics industry. Cargillsubsequently assembled a list of partner attrib-utes, and the Dow Chemical Company emergedas the best candidate. After about 18 months ofdiscussions, the Dow Chemical Company agreedto pursue the concept of NatureWorks PLA and,in 1997, signed a 50:50 joint venture agreementcreating Cargill Dow LLC. In January 2000, theparents were convinced of its commercial viabil-ity and agreed to invest $300 million to fund thebuilding of the Cargill Dow Blair facility.

Several key government and industry groupsalso helped Cargill Dow develop and commer-cialize NatureWorks PLA. The U.S. National In-stitute of Standards and Technology providedcritical research support and scientific study tohelp make PLA commercially viable. The U.S.

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Grains Council helped open up internationalmarkets for PLA, actively working with CargillDow to raise the awareness of PLA in key geo-graphic markets, particularly in Japan. And theU.S. Department of Energy funded research toimprove the performance of polylactic acid poly-mers in a joint project between Cargill Dow, theColorado School of Mines, and the U.S. Na-tional Renewable Energy Laboratory.

Performance without Sacrifice

Although environmentally sound productsare highly desired by consumers, performance isthe ante for even being considered. What makesNatureWorks PLA an attractive option for con-verters, mills, manufacturers, brand owners, re-tailers, and consumers is that it offers perfor-mance in the fiber and packaging markets that ison par with existing materials. In the packagingsector, the resin can be used in film, rigid, andbottle applications. Some of the inherent physi-cal properties that the resin provides includehigh gloss, superior clarity, very good optics,strong deadfold, and the abilities to be heatsealed, retain flavors, provide an odor barrier, andbe processed on existing equipment. Nature-Works PLA is suited for a range of applications,including thermoform trays, bread bags, twistwrap, venue cups, floral wrap, envelope windows,and blister packs.

Ingeo� fiber is a new brand concept for fibersmade from PLA. The new fiber can be used in arange of fiberfill, knitted, and woven fabrics andnonwoven applications. These include bedding,clothing, wipes, carpet tiles, and upholstery, aswell as interior and outdoor furnishings.

Ingeo fibers combine many of the desiredphysical characteristics of natural fibers, such aswool, cotton, and silk, with those of conven-tional, petroleum-based synthetics. Benefits in-clude superior hand and drape, better wicking,comfort, moisture management, ultraviolet(UV) resistance, and low odor retention.

In addition to the performance attributes ofthe resin, NatureWorks PLA offers significantenvironmental benefits. The process used to cre-ate NatureWorks PLA can use 20% to 50% fewerfossil resources than is required by conventionalplastic resins. And, because carbon dioxide is re-moved from the atmosphere in growing corn, the

overall carbon dioxide emissions can be 15% to60% lower than comparable plastics, such aspolystyrene (Slater et al. 2003). The solvent-freeprocess for making PLA also ensures that thereare no hormone disrupters, an emerging issue insome traditional thermoplastics and at the centerof health concerns related to plastics.

Differentiating the polymer from competitivematerials, NatureWorks PLA fits all current dis-posal options, with the added benefit of beingfully compostable in municipal and industrial fa-cilities. NatureWorks PLA incinerates cleanlywith lower energy yield than traditional poly-mers. PLA polymers also contain no aromaticgroups or chlorine and burn much like paper, cel-lulose, and carbohydrates. Combustion of PLAproduces few by-products and 0.01% ash (Vinket al. 2003). In areas where capacity is limited,this is an advantage in that the lower heat out-put permits a higher incinerator facility through-put.

Municipal composting is a method of wastedisposal that allows organic materials to be recy-cled into a product that can be used as a valuablesoil amendment. Extensive testing at laboratoryand pilot scales according to international stan-dards, and in actual composting facilities, dem-onstrates PLA polymers are fully compostableaccording to International Organization for Stan-dardization (ISO), European Committee for Stan-dardization (CEN), American Society for Testingand Materials (ASTM), and German Institute forStandardization (DIN) draft regulations. DIN-Certco Compost Certification has been awardedfor PLA polymer use in Germany.

PLA can also be recycled. Just as for all othermaterials, the practicality of this depends uponthe economics of collection. Once large amountsPLA are available in the marketplace, it may bepractical to develop the infrastructure to recyclePLA from postconsumer waste. Interestingly,PLA can also be recycled by converting it backto lactic acid, which of course could be used forPLA or other applications.

The Business of Sustainability

Remaining true to the original criteria for de-veloping sustainable products, Cargill Dow wantsto be a successful company that is sustainable.Therefore, the company has built a business

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model around managing its products from cradleto grave to ensure that a good idea is also goodfor business, the environment, and/or society.Cargill Dow investigates and accounts for all po-tential environmental impacts, so that it can un-derstand and reduce them over time by workingacross the business system with suppliers, cus-tomers, and waste managers.

Research shows that technological advance-ments in the production of PLA could allow upto an 80% to 100% reduction in net carbon di-oxide emissions, and Cargill Dow is exploring al-ternative, non-petroleum-based forms of energyto further reduce reliance on fossil fuels. Theyalso are looking to biomass feedstocks, such asstalks and straw, which are abundant, oftencheaper than corn, and can provide farmers asecondary source of income.

Cargill Dow also asks suppliers and customersto look at the life cycle of their processes andproducts and ask that they commit to decreasingtheir environmental footprint as a prerequisite tousing NatureWorks PLA and Ingeo fibers.

The Future

Successful commercialization of NatureWorksPLA shows all types of stakeholders that it is infact possible to make products more sustainablewithout compromising price and performance.Cargill Dow expects and hopes that other com-panies will follow with similar products.

The biorefining process Cargill Dow uses toproduce lactic acid and PLA has the potentialfor applications beyond PLA resin, translating tothe production of green chemicals, solvents, ad-ditives, catalysts, biofuels, and specialty chemi-cals. It is the basis for a biobased chemicals andplastics industry capable of delivering productssociety desires with a smaller environmentalfootprint. In fact, the biological system doeschemistry humans could not do otherwise.

Considerable work is needed, however, totranslate understanding into significant indus-trial impact. Government, industry, and acade-mia must work together to optimize each andevery component needed to deliver the technol-ogy and the financial cases required for capital-izing biorefineries. Research shows the benefitsare worth the effort. In addition to the environ-

mental and related social benefits, the economicsare meaningful, considering that the successfulintroduction of a biorefinery economy in theUnited States would have a dramatic impact onthe economy of rural America. To this end, Car-gill Dow has joined Genencor and other industrypartners in coordinating a project to develop andvalidate processes for delivering the technologyand to make the financial case required for cap-italizing sustainable biorefineries for the produc-tion of chemicals, materials, and fuels from lig-nocellulosic biomass.

By shifting away from petrochemicals to bio-based raw materials, a new industry is enabled.The biobased industry will emerge not tied to theend of a petrochemical supply chain (or pipeline)but instead in the midst of agricultural regions.This means new jobs and new capital investmentin rural economies. It means a shift away froman extractive society to one where the raw ma-terials and products can be produced by moresustainable techniques with local raw materialsand jobs.

Notes

1. NatureWorks, Ingeo, and the Ingeo logo aretrademarks of Cargill Dow LLC.

2. Editor’s note: “Poly(lactide)” or “PLA” means apolymer derived from the condensation of lacticacid or by the ring-opening polymerization of lac-tide. The terms “lactide” and “lactate” are usedinterchangeably. Polylactide or polylactate is acommercial, biodegradable polymer that is usedfor a variety of packaging, medical, and other ma-terials applications. Lactic acid, lactide, and po-lylactide all occur as chiral molecules. Chiralmolecules are molecules that are so asymmetricthat they are nonsuperimposable on their mirrorimages. That is, they have “handedness” in theway gloves are left- or right-handed. Lactide oc-curs in three forms: the two chiral isomers of lac-tide, l-lactide and d-lactide, and an achiral formknown as meso-lactide. The predominant stereo-isomer in the lactide polymer product is l-lactide.Thus, the terms “polylactide” or “PLA” used inthis article and “poly-l-lactate” or “PLLA” usedin the article by Sakai and colleagues (2003), inthis issue of the Journal of Industrial Ecology, alldescribe the same material.

3. Editor’s note: For a description of another routeto producing this biopolymer, see the article by

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Sakai and colleagues (2003) in this issue of theJournal of Industrial Ecology.

References

Sakai, K., M. Taniguchi, S. Miura, H. Ohara, T. Mat-sumoto, and Y. Shirai. 2003. Making plastics fromgarbage: A novel process for poly-l-lactate pro-duction from municipal food waste. Journal of In-dustrial Ecology 7(3–4): 63–74.

Slater, S., D. Glassner, E. Vink, and T. Gerngross.(2003). Evaluating the environmental impact ofbiopolymers. In General Aspects and Special Ap-plications. Biopolymers, Vol. 10, edited by A.Steinbuchel. Weinheim, Germany: Wiley.

Vink, E. T. H., K. R. Rabago, D. A. Glassner, and P. R.Gruber (2003). Applications of life cycle assess-ment to NatureWorks polylactide (PLA) produc-tion. Polymer Degradation and Stability 80: 403–419. �www.cargilldow.com/corporate/life_cycle/docs/PLA_Article.pdf�.