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Performance plus: Coatings on demand

Advanced Textiles, Business, Feature | March 1, 2011 | By:

On demand: collaborating on fabrics, products and value-added coatings.

Just as Clark Kent flexed his super powers when he emerged from a phone booth, fabrics take on high-performance properties when they emerge from today’s high-tech coating processes.

In what appears to be a sleight-of-hand trick, a video by P2i shows two boots dunked in a tank of water; the one treated with the U.K.-based company’s ion-mask™ emerges as dry as the Atacama Desert. Combining plasma and nanoscopic technology, P2i applies a coating 1,000 times thinner than human hair that is able to add liquid repellency to fabrics, as well as to metals, plastics, ceramics, glass and paper.

“Even complex 3-D objects incorporating several different materials can be treated successfully in a single process … due to the fact that it is applied to finished products,” says Stephen Coulson, chief technical officer. “This is a crucial difference from old water repellency approaches, such as hot chemical dips and sprays, in which product components are treated prior to manufacture.”

P2i’s coating process does not affect the look and feel of the products it protects. “This is especially important in fabrics, where it preserves inherent qualities such as drape,” Coulson says, adding that treated fabrics also maintain their breathability. While it can be used on bolts of fabric, doing so overrides its greatest advantage: the penetration of every exposed facet of a product. “For example,” Coulson says, “in footwear, this means not only the uppers but also the laces, stitching, toe box and heel collar.”

P2i sells its processing machines to end-product manufacturers and third-party facilities worldwide.

Alexium Intl. Group Ltd., an Australian company operating from a plant in Greer, S.C., licenses its cutting-edge technology and builds reactive surface treatment systems for a range of industries, including textiles. Through exposing materials to seconds of “cold” microwave energy, Alexium’s process forms nanoscopic coatings that can apply multiple functions in one step and graft organic and inorganic compounds onto a wide range of substrates. In addition to standard synthetics, aramids and natural fibers, Alexium’s RST process works extremely well on high-end fabrics such as cashmere and wool, where the feel is important and fibers are sensitive to washing and pilling.

“There seems to be no real limitation on what we can apply it to,” says director Stefan Susta. Alexium, he notes, is working with SSM Industries Inc. of Spring City, Tenn., a protective fabric manufacturer, to license the technology for refueling gloves and coveralls, combining fire resistance and liquid repellency.

The size of Alexium’s equipment depends on the required throughput speed. Susta estimates the capital investment for a typical textile application would run between $250,000 and $500,000. “In terms of training, it’s no different than running a convection oven,” he says. As to the effect on an existing product line, Susta says the company envisions “providing modules that go into their production line or chemical application process.”

One on one

Sister companies based in Coshocton, Ohio, Buckeye Fabric Finishing Co. and Excello Fabric Finishers Inc. offer floating knife and saturation coatings that provide fire, water and mildew resistance on cotton, cotton blends, polyester and nylon for the agriculture, construction, recreation and transportation industries. With a combined history that dates back to 1922, the companies have experienced a lot of changes, even within the past five years.

“We have had more emphasis on an approach to partner with each customer on a one-on-one basis,” says Kevin Lee, president. “We’ve found that many companies have their own unique requirements, and that’s where we can assist them. There’s more collaboration, more conversation than there used to be.” Lee speculates that trend may be because there are more choices for companies to consider and they feel less comfortable making those decisions independently.

“We have a testing facility to determine properties of the fabric before and after coating, and that’s something we offer in working with customers,” Lee says. “By doing lab and plant trials, we can confirm the fabric and coating will perform as desired.”

Another change has been in logistics. “Many fabrics often come directly to our facility and bypass the warehouse,” Lee says. “We never had bulk containers on our property beyond five or six years ago, and now it’s a pretty frequent occurrence. We break down the containers and inventory.” Though the companies charge a portion of the labor cost, the extra work is provided primarily as a value-added service.

“Customer requests drive over 50 percent of our new development work,” says Steven Wood, president and CEO of Vintex Inc. “It’s always easier to commercialize a new product when you’re working with a customer who needs a solution versus developing something where its value is yet to be realized.”

The Ontario, Canada-based company uses extrusion coating to create a mechanical bond between the polymer coating and interstices of the fabric, primarily synthetic yarns, but also poly/cotton blends for gym mats, divider curtains, banners, tents, awnings and other products.

“We are constantly working with individual customers to develop new materials for new applications and to refine their current products so as to improve functionality and durability and global cost competitiveness,” Wood says. “Vintex prides itself on finding the right balance of textile design, formulation design and coating process to provide our customers cost-effective, highly durable, reusable solutions.”

Stephen Bodnar, director of marketing for Duro Textiles LLC of Fall River, Mass., echoes the belief in addressing individual needs.

“Our customers generally have a product specification they need to meet. Duro will formulate a solution to meet those specifications,” Bodnar says. “If the customer is not sure what they require, our technical team can recommend a solution based on experience and a vast knowledge base.”

Duro offers a wide range of performance properties, including UV resistance, antimicrobial protection, fire retardance, stain and water repellence and abrasion resistance through floating knife applications of urethane, acrylic and silicone coatings, as well as nitriles and blends. Upon special request, Duro also will coat Kevlar®, Nomex® and glass-based fabrics.

Covering the bases

The same fabric that gets an A+ for being sustainable may get a D- for its ability to repel liquids and fire or resist stains, abrasion and microbes. But the process of coating raw fibers and fabrics raises obvious concerns about the environmental effects of adding noninherent properties to a substrate: How green is the coating process? And can the coated fabric be recycled?

According to Stephen Coulson at P2i, the company’s ion-mask technology does not use solvents or large amounts of heat. “It uses only a tiny quantity of protective monomer, creates negligible waste and produces no residues, leachables or extractables,” he says.

“Our process is a very energy-effective technology compared to conventional heat,” says Alexium’s Stefan Susta about the company’s patented reactive surface treatment to add functional properties to fabric. “We use enough microwave to have the reaction occur, but it’s still a cold process. In addition, the chemistries are environmentally benign. We use no petroleum products whatsoever.”

While Alexium’s technology is fairly new, Susta says fabric coated by the process should be able to be recycled. Further, he adds, “We have not identified any by-products that would hurt the environment. We consider our process and chemistry completely green.”

According to Stephen Bodnar at Duro Textiles LLC, the main challenge to recycling is a fabric that is a different polymer material than the coating system. “When you have dissimilar materials bonded together, recycling is often impossible,” he says. “Duro does offer polyester-based fabrics with polyester-based coatings that can be reformed into reusable chip material.”

As a business-to-business company, however, Duro Textiles fields few questions about recyclable coated fabrics.

“Contrary to all the green hype from the media and politicians, we do not see our customers readily switching to these products, primarily due to extra cost and the fact that consumers simply don’t throw their jackets into recycle bins every day like they do with their used water bottles,” Bodnar says. “Duro is concentrating on reducing plant emissions, lower energy use and using greener chemicals where we can. We feel this will have a greater impact on the business-to-consumer environment.”

Buckeye Fabric Finishing Co. and Excello Fabric Finishers Inc. also receives few inquiries on environmentally friendly coatings, but Kevin Lee says he continues to search for new products to achieve the best sustainability possible.

“Durability is always one of the critical issues,” Lee says. “People want things to last as long as they can. There continue to be new additives, new components to extend the durability of new products, which benefits everyone.”

That’s a key factor for Vintex, says Steven Wood.

“Our global customer base continues to demand vinyl products due to its durability, reliability and flexibility,” he says. “PVC’s track record has shown it to truly be a ‘super polymer.’” Whether it is cost per use in a health care setting or durability in a packaging environment, vinyl continues to be the polymer of choice.

Lifecycle analyses by the American Reusable Textiles Association (ARTA) and other organizations support Wood’s perspective. For example, one ARTA study found that the environmental footprint of single-use radiological protective garments was about 18 times larger than that of conventional, multiple-use garments.

More than a decade ago, Vintex, in partnership with other companies (primarily mold injection operations) developed methods to recycle its multipolymer waste. This waste stream is captured and made into a variety of products, such as floor tiling, mats and plumbing fixtures. Vintex also uses its single polymer waste as regrind for its other products or as a raw material source for partner companies.

“In addition, we have been investigating the potential for end-of-life product recycling,” Wood says. “Our experience to date suggests the primary challenge centers around the logistics of collecting and segregating end-of-life fabric from a wide geography in a cost-effective recycling process. We continue our efforts to find viable solutions.”

Janice Kleinschmidt is a freelance writer based in Palm Springs, Calif.

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