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Carbon fiber: A decades-long phenomenon

July 1st, 2013 / By: / Feature

High technology products and markets often have long and costly development times, areas usually left to large companies to pursue. Carbon fiber (CF) fabrics and products are such segments. Carbon fiber reinforced composites (CRFP) are replacing steel, aluminum and fiberglass composites in a growing list of product ranges. Because of the steep material prices and apparent process complexity, many never consider it as a potential market.

That may be changing. New and important markets appear to be finally emerging after years of development. Promises of less costly materials, ready availability and more efficient production techniques are driving expanded utilization, including the consumer sector. Significant opportunities, even for smaller companies, are emerging. While much attention is being given to carbon composites in commercial aircraft, wind energy and automotive areas, there is so much more. Now is a good time to take a good look at this market.

Carbon fiber fabrics and applications have a history going back to the early 1960s, primarily a product of the Cold War’s defense programs and the space race. Properties such as high strength-to-weight ratio (CF is five times stronger than steel), stability and extreme temperature resistance made it desirable for areas where the performance demands justified the high cost.

Production of end products required expensive hand lay-up techniques, making it unsuitable to compete with steel and aluminum in high volume production of large and complex items. CF was primarily relegated to areas where its extreme capabilities could be best utilized and afforded, and its development to the so-called “carbon elite”—with government assistance, of course.

How it’s done

Carbon fibers are made by starting with a base fiber, called a precursor, and heated to extreme temperatures to cast off most of the noncarbon molecules, which results in bundles of parallel fibers called tow. The number of filaments in the tow (bundle) determines its size. Fibers are usually classified as low modulus (less stiff) being under 6K (6,000 fibers in the bundle), mid modulus (12K), and high modulus (above 24K), most often used for high performance industrial applications. Most tow is in continuous filament form, but a growing demand is developing for “discontinuous” filament where the tow is stretched during a subsequent spinning process so the fibers rupture in a predetermined manner, making a yarn/fabric with more textile-like properties.

Earlier efforts used a special rayon for the precursor. It was not efficient, so polyacrylonitrile (PAN) fiber was developed, which yields a much higher carbon content when carbonized. PAN became the precursor of choice, accounting for as much as 90 percent of the market.

Because of PAN’s extremely high cost, newer methods are being studied, mainly olefins (similar to polypropylene) and lignin, a wood fiber cellulose material also used in paper making. Oak Ridge National Laboratory, in Oak Ridge, Tenn., has major programs to find precursor alternatives. With CF costing more than $10 per pound (>$22/kg), a lower cost precursor and improved production techniques may enable achieving the long-sought-after benchmark price of $5 per pound  ($11/kg), making carbon much more affordable and leading to more end product manufacturers adopting it for mainstream applications.

Japanese companies dominate CF production. Toray Industries Inc. is the world’s largest producer, followed by Toho Tenax Co. Ltd. and Mitsubishi Rayon Co. Ltd. In the U.S., Zoltek Companies Inc., St Louis, Mo., is the fourth leading global producer, followed by Hexcel Corp., headquartered in Connecticut, and Cytek Industries Inc., headquartered in New Jersey.  The leading European producer is SGL of Germany.

These seven companies account for more than 90 percent of carbon fiber production. China, India, Turkey and Russia promise to be major factors in production as they gear up for greater volume. Russia has a long history of internal use in its space and military programs.

Who uses CF

The industrial market, the largest at 45 percent, is dominated by the wind energy sector, where the high strength and light weight of carbon fiber allows larger blades. That market is considered uncertain by some because the U.S. subsidies have ended and many planned facilities have been put on hold. Globally, wind energy is projected to continue to be a dominant and driving force for CF. Other market areas include automotive, construction and pressure vessels.

Aerospace will grow because most new commercial aircraft use 45–55 percent CFRP. Military and fixed-wing aircraft will continue to be a major user, although the uncertainty of the future of the F-35 fighter and U.S. defense spending reductions will have an impact. Space vehicles, business aircraft and engine parts industries will all benefit as more carbon fiber is used in structural components.

Consumer products make up a wild card category with a projected high growth rate. More items are being made of carbon fiber reinforced composites, such as golf clubs, fishing gear, racquets and marine components. This is likely a good place for the average technical textiles participant to look for potential.

Pharr Yarns LLC, McAddenville, N.C., a major spinner of high performance fibers, is no stranger to difficult fibers. Several years ago it saw the potential and began development of a carbon fiber stretch-breaking yarn system. Success did not come overnight; it required development time, money and patience. Mike Strader, new business innovation manager, says the resulting patented process produces a material offering alternatives in weight and fiber blending not possible with flat filament, as in the majority of carbon fabric production. Compared to other 6K filament materials, Pharr’s process allows 30–40 percent better inter-laminar shear properties, easier wet-out in most resin technologies, softer, more textile-like fabric for easier lay-up, and better economics and control of fabric weights.

Pharr produces 0.8-6K in plied yarns on a commercial basis for a variety of markets from bicycles to automotives, aerospace and nuclear energy. Primary customers are weavers, including 3-D weavers for “made-to-shape” items and other fabric forms. Strader says the company is focusing on stronger, lighter and more impact-resistant solutions that provide value-added elements.

He has a caveat for those wishing to enter the market. “Carbon does not follow norms of weaving, and knitting is practically impossible. Speeds and methodology, such as contamination, and machine factors present challenges to normal textile producers,” he says.

Much of what Pharr is doing is, of necessity, proprietary, but the company appears to be on the right track and has added an important element to its high-performance business model. Spinners and fabric producers willing to do what is necessary could enter this market of potential.

Automotive, in particular

Many analysts feel the most important breakthrough in the use of CFRP will come from the automotive sector. Paul Pendorf, president of AMT II Corp., New York, N.Y., a private investment and management company, points out that the BMW i3 MegaCity urban electric car, due out by late 2013, will be a game changer. A four-door version i8 is due out a year later. All structural and skin parts of this car are made of carbon fiber composites, yielding exceptional strengths and integrity with much lower weight. The company’s plans mean it will utilize a lot of carbon. What to do?

BMW partnered with Germany’s SGL to build a $100 million single-purpose “green” energy plant in Moses Lake, Wash., to produce the carbon fiber. Located near a hydroelectric plant, energy costs are half that of others, a major factor in CF production. The new plant has recently brought a second line into production; the two lines will be capable of producing about eight percent of the world supply of carbon. The fiber will be shipped to a plant in Germany where it will be made into a fabric using a stitch-bonding process that keeps the CF fabric flat and without crimp. Special molds, equipment and techniques were developed by BMW and its partners to ensure a rapid cycling production process, making reasonably high volumes more cost effective.

Pendorf says BMW has hit a home run and is at least five years ahead of everyone else with this technology. Once BMW gets cars out there, he says, “Everyone will want to jump on board and adopt similar processes. Expect this development, and the anticipated reduction in cost of the fibers, to make a huge impact in the automotive field, one that has been trying to find efficient ways to use carbon for many years.”

John Brook Jr., owner of Engineered Textile Solutions LLC, New York, N.Y., and an early and active participant in the field, concurs with Pendorf about the growth of carbon use in automotive markets. “The use of CF in automotive is real and growing,” he says. “The keys to success will not be solely low-cost carbon fiber but rather the development of fast-curing, low-cost, robust, resin systems that can operate within vehicle life cycles and be produced within the environment of basic existing car production factories.”

Pendorf says companies with $50–100 million in turnover are ideal to enter and sustain development in this field, but smaller companies can compete because so much of the development of the materials, process, and many applications have been refined by others. Pendorf emphasized strongly that management in those companies who consider CF markets must have some common ground and understand the technology and risk taking. When BMW’s process is proven to be successful, he says, venture capitalists and investors will be more willing to provide the money needed for new ventures.

While not every company in technical textiles can effectively utilize carbon fiber fabrics in their products, for many it is worth a look. Innovation, lower costs and improved production techniques will offer great opportunities for those willing to do their homework, and especially for smaller companies in the consumer sector.

William C. Smith is a technical textile consultant. He can be reached at billsmith@intexa.com (www.intexa.com).