Material world

The Baltimore Sun

Microfiber is weaving its way through our lives.

It's in the chamois that dries your car and the bath towel that dries your body. It's in dress shirts, underwear, surf shorts, hiking boots, raincoats, sofas, hospital mops and surgical masks.

In October, the ubiquitous fiber crossed a new frontier: The National Basketball Association announced that it would replace the traditional leather that covers the league's basketballs - a change that outraged purists.

So what is this stuff? And why the hoopla?

"Microfibers are any fibers finer than silk," said Ingrid Johnson, a professor at New York's Fashion Institute of Technology.

More precisely, the textile industry defines a microfiber as having a density less than one denier - the scale it uses to measure the fineness of fabric. Fine silk, for example, is about 1.25 denier. Some microfibers are 100 times thinner than a human hair.

Most are made from well-known petroleum derivatives such as polyester and nylon, but feel and wear a lot better than synthetics of decades past.

They are produced by methods borrowed from nature's fiber experts. Silkworms and spiders make their thread by forcing a fluid through tiny holes in a perforated appendage known as a spinneret. In the early 1900s, textile makers came up with mechanical versions of these spinnerets that worked like pasta makers.

By extracting cellulose from trees and plants and forcing it through the holes in the spinneret, they created rayon, the first manmade fiber. Manufacturers later figured out how to extrude molten petroleum derivatives through spinnerets to produce other synthetics.

Nylon made its early mark in women's stockings, parachutes and toothbrush bristles. Polyester, which was first manufactured in the 1940s, gained notoriety in the double-knit bellbottoms and butterfly-collar shirts of the '70s. They were cheap, durable, wrinkle-free and famously uncomfortable.

While polyester was coming and going, manufacturers were working on finer fibers. A Japanese company, Toray Industries, claims to have produced the first microfiber fabric, Ultrasuede, in 1970. DuPont was the first American manufacturer in 1989, as the fabrics were gaining a foothold in the United States.

"Microfiber was in Calvin Klein raincoats by the '80s - and then in Beanie Babies," said the fashion institute's Johnson.

One early but enduring use of the high-tech fabric was in the long underwear popular with outdoor enthusiasts. The thin, flexible threads produced tight weaves that wicked moisture away, but felt better against the skin than wool or the scratchy polyester of the '70s. New petroleum-based fiber also absorbed less water than natural fibers.

"It dries quickly and it's more resistant to UV light," said John Weld, owner of Immersion Research Inc., a Pennsylvania company that makes microfiber paddling shorts for kayakers, rafters and canoeists.

Some microfiber weaves are so tight that they block wind and water, yet breathe much better than early polyester fabrics, experts say. The fibers are also known for their good "hand," textile industry jargon that means they are pliable and pleasant to the touch.

Fashionistas and furniture makers also fancy them. The durable fibers are used as upholstery in cars and living rooms, and clothing that runs the gamut from Victoria's Secret bras to Donna Vinci dresses to skintight Under Armour warm-ups.

"If I gave you a swatch of polyester microfiber, you would say it is the finest silk you ever felt," Johnson said. "Under the fingers, it just feels wonderful at times."

Johnson said many clothing designers like to work with microfiber and its blends because the quality is more predictable than natural fabrics. "The thing about technology," she said, "is that it can consistently make a product the way you want it."

Slippery when wet?

NBA officials said consistency was a major reason for the switch this fall to Spalding microfiber-covered basketballs - the league's first ball change in 35 years. They said the absorbent but quick-drying fabric provided better feel and grip than leather basketballs when they got moist from players' sweat.

Miami Heat center Shaquille O'Neal and some other NBA players disagreed. They complained that the balls were indeed consistent - consistently slippery. But NBA Commissioner David Stern has insisted the artificial stuff is here to stay.

Microfibers have also threaded their way into cleaning products such as kitchen towels, mops and car wash cloths. These products often use fabrics in which the already-thin fibers have been split into even finer strands, according to Curt Rodenhouse, chief executive of Excello Products LLC, a Chicago-based company that sells a variety of microfiber products.

The split fibers provide greater surface area for capturing dust and dirt and holding water, he said. "They are really making it big-time into the janitorial markets."

Microfiber mops used in hospitals require 95 percent less water and fewer chemicals than traditional mops, according to a study by the Environmental Protection Agency. Although they cost three times as much as traditional mops, the agency said, they last five times as long.

Rodenhouse said his company is also investigating microfiber bedsheets with weaves so tight that bedbugs can't bite through them. Such tightly woven fabrics are already used in water filters, air filters and hospital masks.

Hoping to develop more applications, Carmel Majidi has returned to the source that first inspired man-made fibers - nature.

Majidi, a graduate engineering student at the University of California, Berkeley, is trying to reproduce the structures on geckos' feet that enable them to stick to vertical surfaces. The tiny fibers are made of keratin, the same material that's in human fingernails.

The current explanation for the lizard's climbing prowess, he said, is that the multitude of flexible fibers on their feet press against a surface and form quantum-level bonds that act like glue. "The gecko can use its adhesive when it wants to and retract it when it wants to," he said.

Trying to mimic the lizard's feet, Majidi and his colleagues have managed to mold a Velcro-like material bristling with microfibers. The material can grip an angled piece of glass, but it lacks the true adhesive quality of the gecko fibers.

"We've only succeeded in achieving very high friction," he said.

The downsides

Despite proven usefulness and promise, microfiber has some drawbacks, experts say. It's made from petroleum, so it gets more expensive when oil prices rise and could become even more so as oil reserves dwindle.

That has prompted some manufacturers to develop microfibers from renewable resources. An Austrian company, Lenzing Fibers, for example, has developed fibers from wood pulp cellulose - like the original rayon. Major clothing manufacturers are using the fibers, including Columbia Sportswear, Adidas and Nike.

Others are trying to recycle old polyester. Polartec, for example, is producing recycled polyester fleece for outerwear maker Patagonia.

Unfortunately, recycled polyester costs more than new fiber, and polyester and nylon clothing tend to melt when exposed to extreme heat, possibly injuring the wearer.

This isn't a problem for most people. In fact, the U.S. Consumer Product Safety Commission recommends wearing polyester and nylon clothing as a fire safety precaution. But melting can cause problems for people such as soldiers, race car drivers, pilots and anyone who sits too close to a campfire.

"I've got lots of little holes in my old polyester fleece," said Greg Williams, a spokesman for Polartec.

He said the company is producing no-melt microfiber underwear for the U.S. military. "It's incredibly [expensive]," he said, "but they don't care."

There is also the matter of fashion stigma - left over from polyester's past. The Fashion Institute's Johnson said many who lived through the days of scratchy, clammy synthetics remain skeptical, although young people don't share those bad memories.

"My generation is an immigrant to technology," she said, "but my children were born to it."

Even the skeptics, she argued, probably own products made with microfibers. "I think people would be surprised where they are," she said.

chris.emery@baltsun.com

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