There was a golden age, from the late 1930s through the mid ’60s, when chemists invented most of the polymers we use today. These materials—nylon, polyethylene, polypropylene, polycarbonate, and polyester, to name a few—quickly took hold with a public eager to remodel its world in colorful, modern, and durable plastics. The days of glass shampoo bottles, paper food packaging, and chrome bumpers were numbered.
In fact, those early plastics were so successful that it has become difficult to launch newer polymers in the marketplace. An established infrastructure of resin producers, plastics converters, and processing machinery makers is dedicated to multi-million-ton-per-year applications such as polyethylene terephthalate (PET) bottles and high-density polyethylene shopping bags. Good reasons are needed to dislodge the standard resins in favor of new, untested materials.
But a few ambitious companies are not dissuaded by these hurdles. These firms say they understand it takes a long time to build a polymer business and promise they have the wherewithal to follow the proposition through. They are also realistic about what the new polymers can actually do and are focusing on those markets where their materials’ properties provide the most value.
“You have a film that can be plowed into the soil at the end of a growing season.”
Among these plastics are petroleum-based materials such as Eastman Chemical’s Tritan copolyester, DSM’s Stanyl ForTii engineering polymer, and Novomer’s carbon dioxide-based carbonate polymers. New biobased materials include Metabolix’ polyhydroxyalkanoates and Avantium’s YXY furanic polymers. Slightly older materials such as NatureWorks’ Ingeo polylactic acid and Topas Advanced Polymers’ cyclic olefin copolymers have been making strides.
The last major resin to break into sizable markets was linear low-density polyethylene, which started to make large gains in plastic film some 30 years ago. Many companies have since unveiled ambitious plans to establish new resins, but the history of the plastics industry is littered with their failures.
The most notorious of these is Shell Chemical’s Carilon, an aliphatic polyketone made from ethylene, propylene, and carbon monoxide that boasted strong heat and chemical resistance. Shell touted Carilon as “one of the most significant new polymer developments since nylon and polycarbonate” and sank hundreds of millions of dollars into its development in the late 1990s, including a 25,000-metric-ton-per-year plant in Geismar, La.
But at about the same time, Shell made a corporate shift to basic petrochemicals and sold off specialty chemicals like styrene block copolymers and epoxy resins. It planned to sell Carilon as well but was unable to find a buyer. Shell donated its aliphatic polyketone intellectual property to SRI International in 2002.
Thus far, Eastman’s experience with Tritan, one of the more successful of the new breed of polymers, offers a sharp contrast. Tritan is a polyester copolymer made from dimethyl terephthalate; 1,4-cyclohexanedimethanol, a diol used in other Eastman specialty polyesters; and 2,2,4,4-tetramethyl-1,3-cyclobutanediol, a diol unique to Tritan.
Tritan is the result of an effort by Eastman scientists to come up with a polyester with the toughness, clarity, and temperature resistance to compete against polycarbonate in the housewares market. Tritan exceeded their expectations, proving to be more dishwasher-durable than polycarbonate, which tends to develop cracks, called crazing, at molded-in stress points. Fortuitously, the controversy over bisphenol A, a polycarbonate raw material, came to a head just when Tritan was introduced in late 2007. Tritan was a ready replacement for polycarbonate in baby bottles and water containers.
“We are making a really big impact in the durables area,” says Emmett O’Brien, a senior chemist at Eastman in charge of Tritan applications development. “When we launched Tritan, we had to go around to all the brand owners and say, ‘Look, try our material.’ And now brand owners are contacting us and asking, ‘Hey, can we try your material?’ The word is definitely out.”
The volumes that Eastman is selling are mounting. The company claims that Tritan is growing faster than polycarbonate did in the 1950s when it was at similar stage of development. The company started up a 30,000-metric-ton-per-year Tritan plant in Kingsport, Tenn., last year. It has already begun construction of another 30,000-metric-ton line at the site that will open next year.
Fred Colhoun, market development manager for Tritan, sees enough applications in the pipeline to keep the new plant running. “We are working very hard on filling up that capacity,” he says.
The company is starting to make inroads in drinkware for restaurants and bars because of Tritan’s shatter and scratch resistance as well as its commercial dishwasher durability. “Customers have reported savings of thousands of dollars by dramatically reducing replacement costs,” Colhoun says. Tritan is also plunging into medical applications.
Much as with Tritan, extending the properties of an existing polymer by incorporating a new raw material into its backbone was the idea behind Stanyl ForTii. DSM launched it in 2007, about a month before Eastman unveiled Tritan, as “the first new polymer to be introduced in the new millennium.” It is the product of reacting terephthalic acid and tetramethylene diamine, the diamine used in DSM’s Stanyl 4,6 high-heat polyamide, itself one of the few successful polymer introductions since the 1980s.
DSM wanted to reduce the moisture absorption of Stanyl 4,6 while retaining properties such as mechanical strength and high heat resistance. DSM saw an opportunity to penetrate electronics applications because of the tendency of the dominant materials, liquid-crystal polymers, to warp and fail at weld lines when subjected to lead-free soldering. The moisture absorption of Stanyl 4,6 could cause blistering, but Stanyl ForTii fixed that problem.
Tamim P. Sidiki, innovation program manager for DSM Engineering Plastics, says the reception has been good. “Typically, the introduction of a new polymer into the market is not very easy,” he says. “Following Stanyl 4,6, this is now the next one that has had a very successful track record.”
DSM opened a market development plant in Geleen, the Netherlands, in 2008, and followed quickly with a new plant at the site that is four times larger. “That plant has been inaugurated and already is basically sold out,” Sidiki says. “We are working now on the next expansion.”
DSM has also started to sample Stanyl ForTii in automotive applications, a strong market for Stanyl 4,6. Here the company is after parts close to the engine as well as electronic components such as sensors and light-emitting diode fixtures.
Ken Sinclair, principal of the polymer consultancy STA Research, says successes like these illustrate that resin producers have become better at identifying market needs. Companies that convert resins into parts are also more sophisticated, Sinclair says. “They are more willing to try something that is new—maybe not totally new but a little bit new—to get an advantage.”
Eastman and DSM both had a good idea of what markets they were after when they started to tinker with their polymer structures. But some companies are still inventing polymers much like their counterparts did in the old days: by coming up with novel chemistry and then sorting out where it will be useful.
Waltham, Mass.-based Novomer is one such firm. It was founded in 2004 by Geoffrey W. Coates, a chemistry professor at Cornell University, to commercialize transition-metal catalysts that join carbon dioxide with epoxide groups. The company’s two major products are polyethylene carbonate and polypropylene carbonate, the result of reacting carbon dioxide with, respectively, ethylene oxide and propylene oxide.
Peter H. Shepard, executive vice president of polymers at Novomer, says his company can control the molecular weight of the polymers from about 1,000 to 200,000 daltons. At the lower weights, they can cross-link with melamine or isocyanates to yield thermoset resins.
For its first application, to be launched next year, Novomer has partnered with DSM, an early investor in the company, to develop industrial coating resins based on the low-molecular-weight polymers. Shepard notes that one potential application is replacing bisphenol A-based epoxy resins in can coatings.
At higher molecular weights, the polymers can be used as thermoplastics. They yield relatively stiff plastics with mechanical properties similar to those of polystyrene. Shepard says the polymers also have strong barrier properties, much like those of PET, making them suitable for blending with other polymers and in multilayer containers.
The major advantages of Novomer’s polymers, Shepard says, are the environmental benefits—they are more than 40% by weight CO2, which is sequestered in the polymer backbone—as well as the potential cost benefits of using such a cheap feedstock. The ideal new plastic, he says, “is a greener polymer that has equal or better performance at a competitive cost.”
Last year, the Department of Energy granted Novomer $18.4 million to develop the polymer platform. As part of that program, the company is using Eastman Kodak pilot-scale chemical reactors near Rochester, N.Y., to make polymers for customer evaluation. It is making bigger quantities in batch reactors operated by Albemarle in Baton Rouge, La. Novomer is planning to use Albemarle’s facility in Orangeburg, S.C., for an even larger scale-up.
Although Novomer executives, no doubt, would like to repeat the quick success enjoyed by Eastman and DSM, they should be aware that other new polymers have had much longer gestation periods. Two examples are Topas cyclic olefin copolymers and Ingeo polylactic acid.
Topas is a polymer of norbornene and ethylene developed by Celanese’s Ticona unit in the 1990s. In 2000, the first commercial Topas plant started up in Oberhausen, Germany, with 30,000 metric tons of annual capacity. In 2005, Celanese sold the Topas business to Japan’s Daicel Chemical Industries and Polyplastics, itself a joint venture between Celanese and Daicel. The business was rechristened Topas Advanced Polymers.
Many of the early applications that Ticona pursued for the polymer exploited its optical clarity and strong moisture barrier properties. One that never panned out was compact discs and DVDs made from Topas.
Indeed, Timothy Kneale, president of Topas Advanced Polymers Inc., says some of the polymer’s biggest applications today are ones the company hadn’t even considered in its early years. When Topas is blended with polyethylene at concentrations of 10 to 20% by weight, it makes polyethylene easier to thermoform. This has helped Topas penetrate the market for air-filled protective packaging. In addition, adding Topas at 20 to 40% concentration helps make polyolefins suitable for shrink-wrap for contoured beverage bottles.
STA Research’s Sinclair says Topas has been the beneficiary of improved polymer blending technology. “The conversion industry and the polymer materials industry have advanced the technology very well in being able to use the polymer in different ways rather than only as a neat resin,” he says. “And that makes it much easier to put it into large markets in small amounts.”
In addition to packaging, optical applications such as cell phone camera lenses, touch screen displays, and light guides are important for Topas. In fact, an undisclosed optical application represents the largest market for the polymer, according to Kneale. He says the firm is planning projects at its Oberhausen plant this fall that will improve quality and modestly raise capacity.
NatureWorks, a subsidiary of Cargill, opened its Ingeo polylactic acid (PLA), plant in Blair, Neb., in 2002 with 70,000 metric tons of capacity. At the time, recalls Steve Davies, director of communications and public affairs, the company had high hopes merely because bioplastics were still new. Converters started experimenting with it for nearly every application under the sun. “It really took the imagination of every manufacturer out there,” says Davies, who was then a company business development manager. “People wanted it to be all things to all people.”
But the polymer’s limitations ensured that it couldn’t be that. PLA is very stiff, which is a detriment in applications that require ductility. It also has poor barrier properties, which is a problem for beverage bottles, and it contaminates the PET recycling stream.
NatureWorks hasn’t pursued the bottle market for three or four years, Davies says. Instead, it has been cultivating markets such as thermoformed cold food service containers, cutlery, flexible packaging, and fibers. “We have gotten good at putting it where it works well and keeping it out of places where it doesn’t.”
Sinclair confirms that environmentally driven applications haven’t been PLA’s savior. But in recent years, he notes, the polymer has benefited from improvements in blending and multilayer technology. For instance, several firms have put out impact modifiers and other additives that improve PLA’s mechanical properties.
And there is a famous example of PLA benefiting from multilayer technology. In 2010, Frito-Lay launched a bag for its SunChips snack product that substituted layers of PLA film for oriented polypropylene. The noisy crinkle of the bags became an Internet joke, and Frito-Lay had to pull them from the market. But the chip maker didn’t give up on PLA. It regrouped and found a new adhesive that could dampen the noise when applied between the layers of film. The quieter PLA bags are being reintroduced this year.
Over the past two years, NatureWorks’ sales have grown by more than 25% annually, Davies says. The company sold out the original PLA line in Blair and opened another 70,000-metric-ton-per-year line at the site in 2009. It plans to build a second plant, this time in Southeast Asia, by 2015.
As with PLA, environmental benefits have been a selling point for polyhydroxyalkanoate (PHA) resins from Metabolix. Telles, the company’s joint venture with Archer Daniels Midland, started up a 50,000-metric-ton-per-year plant in Clinton, Iowa, last year that uses microbes to ferment corn sugars into PHA.
The main attraction of the polymer, called Mirel, is its strong propensity to biodegrade, says Richard P. Eno, Metabolix’ chief executive officer. Mirel can break down in industrial and home composting environments, anaerobic digesters, and even in soil and marine environments. In addition, Mirel has tear and puncture resistance similar to that of linear low-density polyethylene.
Eno says the company is exploring thermoforming and injection-molding markets for Mirel. But the focus recently has been on film for agriculture, packaging, and bags. Shopping bags and 13-gal garbage bags are a good fit for the polymer, Eno says. Larger institutional can liners are more challenging applications because their loads currently push the limits of Mirel’s tensile strength.
But the applications where Mirel works well are fertile ground, Eno notes. Its biodegradation properties are an advantage in a number of markets, he says, such as in locations where plastic shopping bags are under regulatory threat or where waste is composted.
The use of degradable plastics can provide real savings in markets without regulatory drivers, including agriculture. “You have a film that can be plowed into the soil at the end of a growing season,” he says. “The farmer no longer has to hire laborers to pick up the film and doesn’t have to pay to haul it away.”
Environmental benefits are nice to have, but the main emphasis for the YXY platform from the Dutch company Avantium is on cost and performance. The firm has found a route to make methoxymethylfurfural and other hydroxymethlyfurfural (HMF) ethers from glucose and fructose. The company has another catalyst that transforms the ethers into furan dicarboxylic acid (FDCA), a long-sought biobased chemical that can be reacted with ethylene glycol to make polyethylene furanoate (PEF), a polyester.
Dirk den Ouden, director of new business development for Avantium, believes that PEF will be a formidable competitor to PET in bottle and container applications. He predicts that it will be cheaper to make bottles out of PEF than out of PET. And although some critics have questioned the impact PEF might have on the PET recycling stream (see page 30), den Ouden says Avantium has shown that PEF has no impact at concentrations of 5% or less.
In addition, den Ouden says, the oxygen barrier of PEF is six times greater than that of PET. This could allow PEF to be blow-molded into small beverage bottles, which push the limits of PET. Similarly, PEF might be suitable for beer bottles, a market that PET has been able to conquer only with oxygen-scavenging additives and multilayered construction. Another plus is PEF’s high temperature resistance, which might allow it to penetrate the hot-filled container market.
The YXY platform extends beyond PEF. Avantium recently formed a collaboration with Solvay to make polyamide resins by reacting FDCA with amines. Similarly, Avantium is collaborating with Teijin to insert FDCA into the backbone of polyaramids.
Avantium will complete a 40-metric-ton-per-year pilot plant for the HMF ethers in Geleen, the Netherlands, later this year. It plans to have FDCA and PEF available for sampling early next year and hopes to have a commercial plant running by 2016.
Among the new polymer developers, Avantium is at the earliest stage of development, and it has some of the most ambitious goals. But like the others, it is trying to avoid the pitfalls that have long been associated with introducing new-to-the-world materials. The nature of the plastics industry is such that it will take years to learn whether any of them are truly successful.