Still Going Strong

Invented more than 30 years ago, Kevlar is the grandfather of the super fibers. But innovations at DuPont’s Spruance plant in Richmond keep the high-strength material looking forever young.

by James A. Bacon

One December morning in 2002, police officers Shane Waite and Rick Edwards were patrolling a neighborhood in the city of Richmond, Va., known for drug trafficking. They stopped a vehicle to check its registration. As Waite approached the car, the driver hopped out and reached for his waistband. A struggle ensued, and then the driver broke free. As Waite made chase, the driver turned and fired six rounds from a .357 caliber handgun, hitting the policeman in the chest.

Waite’s body armor stopped the bullet. He and Edwards returned fire and dropped the assailant. Waite was treated at a local hospital for severe bruising – even with body armor, the bullet had the same impact as if someone had slammed him in the chest with a hammer – but he lived to tell the tale.

Waite is one of more than 2,700 law enforcement officers nationally who have survived potentially fatal or disabling injuries because they were wearing personal body armor –- much of it made with Kevlar, manufactured, ironically enough, by DuPont in Waite’s home town of Richmond. Numerous products - Spectra, Zylon, Dyneema, Twaron – have invaded the marketplace since DuPont’s miracle fiber was first field tested for body armor in 1975, but Kevlar remains as synonymous today with super-strong fabrics as Kleenex is with paper tissues and Xerox with copiers.

Although Kevlar is a mature product, DuPont has breathed new life into it by refining manufacturing processes, devising synergies with new materials, inventing novel ways of using the same fiber and developing new applications. “Kevlar is approaching 30 years, but I wouldn’t call it old,” says Alexa Dembek, global business manager for DuPont’s life protection division. “There have been many innovations since that molecule was discovered. … The basic molecule has not changed, but the technology that allows that molecule to realize its full potential continues to advance.”

While meeting surging war-time demand for the fiber in military body armor in the past two years, the Kevlar team has unveiled an upgraded body-armor product for the U.S. law-enforcement market and introduced anti-terror protections for aircraft such as armored cockpit doors and blast-resistant cargo containers. Meanwhile, on the home front, Spruance has developed an entirely new civilian product -- high-strength panels to guard homeowners against debris hurled by tornadoes.

The world center of Kevlar manufacturing, R&D and product development is DuPont’s Spruance plant in south Richmond. Thanks in large measure to Spruance, the Richmond-Petersburg area has emerged as one of the world’s leading centers of innovation in high-performance fibers. Besides Kevlar, the region is home to manufacturing and R&D for DuPont’s high temperature-resistant fiber Nomex, Honeywell’s high-strength fiber Spectra, and M5, a new generation of super fiber ramping up for production at Magellan Systems. Indeed, the Greater Richmond Partnership, the Richmond region’s economic development group, sees DuPont, Honeywell and Magellan as the nucleus of a potentially world-class advanced materials industry.

Kevlar is a dominant player in a lush global ecology of businesses numbering body armor manufacturers, specialty textile companies that weave the high-performance fibers into fabric, and a parade of businesses concocting unique and unusual applications for super-strong fibers. A search of the word Kevlar in the U.S. Patent Office database reveals 8,170 patents filed since 1976 that cite uses for the fiber in inventions as varied as fishing gear, utility-pole drilling rigs, multi-layered golf balls and fiber-optic cable. The potential applications, it seems, are limited only by the imagination.

Gene Winter, senior vice president for the Greater Richmond Partnership, urges body armor-manufacturers and other users of high-strength fibers to locate in the Richmond region where they can stay close to the center of innovation. “The industries that use Kevlar and other high-performance materials are incredibly competitive,” Winter says. “The companies that succeed will be those who can innovate the fastest – in other words, those who are most plugged into the highly specialized markets, technologies and manufacturing processes associated with aramid fibers. Knowledge is king. And in this business, the throne is here in Richmond.”

DuPont scientist Stephanie Kwolek discovered the Kevlar compound in 1965 in the course of her research into synthetic fibers. One day, as the story goes, her laboratory experiments created a polymer in the form of a cloudy fluid. Her co-workers, looking for a product that was viscous and clear, urged her to throw it out. But acting on instinct, she spun out the solution. The resulting fiber was stiffer and stronger than any created before.

Investigation revealed that Kevlar had remarkable properties. Ounce for ounce, it was five times stronger than steel. It was structurally rigid – in other words, it did not stretch. The compound was flame resistant and chemical resistant, and it displayed low electrical conductivity. DuPont began exploring a host of potential applications.

The federal government was among the first to see the new material’s potential. In 1973, researchers at the U.S. Army’s Edgewood Arsenal developed a Kevlar vest for field trials. Bulky Vietnam-era flak jackets protected against fragments hurled by explosives but could not stand up to bullets. The light-weight Kevlar was clearly superior to the old materials, though not without its drawbacks. Experiments showed that exposure to water and sunlight diminished the material’s effectiveness, but those flaws could be corrected either by combining Kevlar with other fabrics or inserting bullet-resistant Kevlar panels into carriers made of other materials.

Meanwhile, concerned by an epidemic of police slayings, the National Institute for Justice invested $3 million between developing concealable Kevlar body armor. By 1975, NIJ undertook its first field test of bullet-resistant vests for police officers. Later, NIJ developed a stringent rating system for body armor that classified the increasing number of products on the market by their ability to protect against bullets of various calibers and, for another line of garments aimed at correctional officers, against stabs and cuts by prison inmates. Ratings backed by a credible third party gave buyers the quality assurance they needed to purchase concealable armor in large volumes.

By 1999, NIJ estimated the market for law-enforcement body armor had grown to an estimated $200 million annually. Spurred by continual innovation in technology and products, the market is still growing. DuPont briefly enjoyed a first-mover’s advantage, but competition soon became a shoot-out for market share. Four other companies sell high-strength fibers for use in body armor, and a sixth is entering the market (see "A Fiber Primer" to the right), each with properties capable of outperforming the others in one way or another. Body-armor manufacturers craving a competitive advantage eagerly embrace new fiber technologies.

The NIJ lists more 60 body-armor companies vying for a piece of the action. These companies, mostly small and entrepreneurial, spit out an endless stream of innovations -- combining new fibers, different weaves, novel combinations of fabrics, unconventional stitching techniques, new resins and composites – to cut the price, trim the weight a few ounces or otherwise improve the comfort of the garment.

Police officers know that body armor saves lives. The trick is convincing them to wear apparel that can weigh three to five pounds, reduce flexibility and trap perspiration. “We look for comfort and wearability,” says Sergeant Dave Cole, who runs the officer survival program at the Virginia State Police training academy. “Body armor doesn’t do any good if it’s in the trunk of a car or in a closet at home.”

All vests must meet NIJ standards for protection. But they vary considerably by price and comfort. The Virginia State Police would love to equip its officers with the top-of-the-line vest, but it can’t afford the $1,000 price tag, Cole says. The force has settled for a less expensive vest that provides the same protection but weighs more. It’s hard to complain, though, he adds. “I’ve worked for the department for 32 years. In the olden days, we had to buy our own vests.”

Failure in this business as is brutal as a slug from a .45, as Toyobo Co. Ltd., the Japanese manufacturer of Zylon, found out when ballistic tests showed degradation of the fiber after exposure to heat and moisture. Zylon, the gold standard in high-performance fibers not long ago, is now nearly untouchable. Second Chance Body Armor, a leading Michigan manufacturer, has stopped using the fiber altogether.

After pioneering the body armor market nearly 30 years ago, DuPont let its market share in the so-called “soft” armor niche erode significantly. But it’s been fighting back in recent years. The company was the first to have its fiber used in concealable, soft body armor worn by correctional officers. Then in 2001, the company launched a partners program with body armor manufacturers to collaborate in R&D with the goal of shortening the time to market of the newest designs and innovations. The result, the company touted in a press release, would be “high-quality vests, outstanding service and advanced technology.”

Last year, DuPont introduced two significant new upgrades to its law-enforcement body armor products: one for the U.S. market, and one for the European. In October, the company unveiled Kevlar Comfort XLT, which it claimed was “at least 25 percent lighter in weight as compared to conventional all-aramid fabric designs.” The company did not elaborate on the nature of the technological advance.

Shortly after, DuPont unveiled Kevlar Impact Control designed for the specifications of the European body armor market. The new armor reduced “backface deformation,” or the depth the body armor, driven by the bullet, punches into the human body and causes what’s known in the business as “blunt trauma.” DuPont cited two crucial innovations. The first was Kevlar New Fiber Technology (NFT), an extra-fine fiber woven into a special fabric construction. The second was a new Kevlar Sigma resin lamination technology, which embedded the super-fine fibers in a specialty resin.

“DuPont’s greatest strength is in the end-use research and development,” says Dembek, DuPont's life protection global business manager. “It’s the ability to take Kevlar and make it work in synergy with other materials in a way that demonstrates value to end users.”

That, apparently, is something that DuPont has been especially effective at doing in the realm of military body armor. “DuPont is very strong in military applications,” says Ed Bachner, group vice president for Second Chance Armor and developer of several body-armor patents himself. “DuPont has done a pretty good job in military body armor in setting the technology pace and continually raising the bar in terms of performance.”

The Defense Department sets the specifications of its “Interceptor” body armor. As long as the equipment meets the specs -- “you just have to be able to stop these particular projectiles at these particular velocities” – DOD doesn’t care what it’s made out of, says Phil Cunniff, a research mechanical engineer at the U.S. Army Natick Soldier Center in Massachusetts.

Thanks to the so-called Berry amendment, which requires the use of U.S.-made materials, Kevlar has only two real competitors in the military market at present: Spectra and Twaron. Spectra, manufactured by Honeywell in Chesterfield County, Va., is the preferred material in rigid plates inserted in the vests. Twaron, manufactured by Teijin Twaron, is based on the same chemical as Kevlar but uses a different spinning technology affecting the width of its strands. The Japanese company managed to get an exemption from the Berry amendment for fiber woven into fabric in the U.S. However, Netherlands-based DSM may join the fray. Having manufacturing its Dyneema fiber in the U.S., the company has begun to chase military contracts as well.

For now, DuPont retains the commanding heights, thanks to continual innovation. “Kevlar’s just damn good – that’s why it’s there,” says Cunniff. “It’s not the same Kevlar that it was in 1972.” Newer versions of the fiber are stronger and less extensible. “There’s a performance advantage in how they put the material together – and the material itself is better.”

Meanwhile, DuPont is working to apply Kevlar to a host of other military applications. Armored boots to protect against toe-popper mines. Anti-fragmentation panels for command-and-control centers. Armored components of helicopters and ground vehicles. On its website, DuPont points to future military applications from lighter-weight helmets to parachutist jump suits, from ballistic blankets to explosive ordnance disposal suits.

Personal protection is a core value at DuPont, a company that has set the standard for industrial safety. It’s not surprising, then, that the company also offers a wide range of industrial safety products. Cut-resistant gloves are a big seller, with finger and hand injuries among the most prevalent in the workplace. DuPont maintains a rotating Plexiglas drum loaded with razor blades that it dubs “the torture chamber.” Gloves of cotton, leather and Kevlar are filled with plastic pellets, dumped into the drum and then tumbled with razor blades. The leather and cotton gloves are shredded within a minute – the Kevlar gloves last for 20 or more demonstrations.

DuPont is pushing sport applications such as "performance apparel," like riding chaps and motorcycle helmets, and even equipment such as kayak oar blades. It also adapts the fiber to industrial applications where resistance to friction and heat are crucial, such as belts, hoses, tires and cable.

The company invites inquiries from anyone who thinks he might have a new use for Kevlar. People have pitched some pretty wild ideas, says Randy Tatham, technical services manager at Hexel Schwebel in South Carolina, a weaving company that works closely DuPont in meeting customer specifications. “We’ve heard things you wouldn’t believe” -- space applications, military applications – even horse booties and dog booties.

“The magic in innovation,” says DuPont’s Dembek, “is understanding how to apply the benefits of Kevlar to a specific end use.”

-- January 27, 2004