Finishing fabric

Coating and laminating treatments enhance fabric performance in important —and multiple— ways.

The fabric itself can be just the beginning. For the end product manufacturer to get the performance qualities necessary to meet today’s stringent regulations and to satisfy the end customer’s high expectations, it is likely that the fabric will be coated. In some cases, it may be coated for one purpose, such as fire retardancy (FR); in other cases, it might have multiple enhancements. In either case, it’s unlikely that the customer will be aware of any physical difference in that fabric.

It’s what you don’t see
Alexium International supplies an eco-friendly, nonhalogen-based chemistry for
FR solutions in textiles, particularly for high synthetic blends, such as nylon and polyester. The company provides its products for coating textiles used in home and commercial furnishings. Its phosphorus-based, aqueous solution offers an FR finish that doesn’t affect—and may even enhance—the physical properties of the fabric.

“We have to be mindful of all those properties and not just the FR, so that to the final user it feels and acts the same as any fabric—if not better,” says Alexium’s Mark Valdario, technical sales, North America and Europe.

“It’s hard to make an FR fabric, through a surface treatment, that can retain its original properties—softness, for example. In home furnishings, foam and latex mattresses are required to provide non-leeching, environmentally friendly FR protection, but you still need to maintain the softness and non-greasy feel,” he says.

Silicone coatings also have a nice drape and feel, a soft hand, and provide a low-cost vapor barrier, making silicone attractive for textile coatings in extreme sports and camping equipment. North American business director Ronald Hanks, Bluestar Silicones, York, S.C., sees greater movement into these areas.

“Typically urethanes are used, but the sun will degrade it over time so manufacturers of high-performance lightweight tents are seeing the benefits of silicone due to less UV degradation,” he says. “We’re hoping that gradually it will move into higher volume markets.”

Bluestar is one of the few fully-integrated silicone manufacturers in the world, according to Hanks. Bluestar’s products are also used in industrial settings for conveyor belts, welding blankets, drapes and aprons.

Follow the money

Alan Prelutsky, executive vice president at Marlen Textiles, New Haven, Mo., says that price is a major factor when customers decide what fabric to use, but there’s more to price than the customer first suspects. Marlen Textiles has been a coater since the early 1950s and is one of the few from that time that’s still around, Prelutsky says. “We have goods woven to our specification and we coat them, laminate them and treat them,” he says.

The company’s fabrics are used almost exclusively in outdoor markets, with marine applications being the largest. Improvements typically have been marginal for this market, he says, and nobody wants to pay for higher end capabilities, such as color-changing technologies.

The company has become Berry Amendment compliant in the last two years, which has had an impact on the company’s business. “We have a much more reliable source of product,” he says. “There’s an increase in raw cost, but it’s also a faster turnaround. When we add everything up, it’s no more expensive. We have lost customers on price, but we’ve had customers [who didn’t buy from us] come back a year or two later and tell us we we’re right.”

The company’s coated products are also in flooring, retail, pet care, aerospace, construction and other markets.

Eco issues

The CLI Group, Paterson, N.J., converts customer materials into custom-engineered products using its environmentally friendly, water-based coatings and adhesives. “We’ve been water based for a long time,” says Daren Silverstein, president. “Water-based coatings and adhesives are becoming more capable in meeting customers’ needs because of advances in polymer chemistry and more suppliers getting into it.”

In the distant past, the easiest thing to do was [C8-based] solvents, he says, without thought that the performance characteristics could be done any other way. But with today’s more rigid environmental standards, it’s difficult to use solvents because of the challenges involved with handling them and disposing of potentially harmful substances.

The U.S. government instigated a voluntary phase-out of C8 (perfluorooctanoic acid or PFOA), by the end of 2015. It is, however, highly effective in repelling liquids, particularly oil-based substances. Coaters and textile manufacturers could use C6 (or even C4) formulations, although they are generally less effective than C8.

“It’s kind of a fundamental paradigm that we find ourselves in,” Valdario says. “We make eco-friendly FR compounds and educate the market on what eco-friendly actually means. There are still halogen-based solutions that are eco-friendly and there are a couple of FR compounds on the OEKO-TEX® list.”

Silverstein says his company has been able to achieve today’s high standards for adhesion, peel performance and water holdout using water-based chemistry. “We probably have some retains that are going on 15–17 years and they still work,” he says.

Case in point, a Barbie® game manufacturer needed a carrier sheet where the adhesive stayed with the liner, not the fabric, which is standard, he says. “In this case the carrier sheet kept it rigid so it could go through the printer. We probably made millions of yards of this stuff. They made hundreds of thousands of these games and each one had eight sheets of fabric.” He suspects that many of these games are still around because of the product’s durability.

Another part of the sustainability issue is in recycled materials. “There’s a push for product made from recycled fibers,” Prelutsky says. The issue is money. “[Recycled material] was 50 percent higher and now it’s 20–25 percent higher, but nobody wants to pay,” he says. Still, he thinks it’s trending that way and there will come a day when recycled is closer in price, and then his company would use recycled fabrics.

Coating vs. inherent

Although researchers are making progress in fiber technology that imparts performance capabilities into the fabric, inherent qualities in fibers are not necessarily competition for coaters.

Alexium is actively involved in the coating products business in about 80 percent of the textile markets that have to be FR, he says. The company is working with the U.S. military on a 50-50 nylon/cotton blend material for soldiers’ garments that provides better protection than inherent fibers at a lower price.

“Inherent fibers have their own problems,” Valdario says. “Abrasion resistance, for example, is a problem with Nomex®. With the 50-50 nylon/cotton, the garment is still intact at 100 washes, and has no change in its FR qualities.” The company is currently hoping—and preparing—for a wear trial for the U.S. military.

An additional natural market space, Valdario says, would be workwear, and although coatings are generally thought of as more expensive, that may not be the case. And coated products allow customers to make a choice between fabrics with inherent properties and coated products. “You’re providing them flexibility, and that is money in and of itself,” he says.

Silverstein says the advent of more advanced fibers and yarns—and, therefore, textiles—has had an impact. “In a sense it’s competition,” he says. “If a fabric manufacturer can achieve certain characteristics in the fabric in general, then it doesn’t need post processing. Years ago, fabric manufacturing didn’t do that.”

In some areas, however, it’s created opportunities. “We make composite materials; we’re not just finishers,” he says. “Maybe those materials can be used in composites that weren’t necessarily suitable in the past.” He adds that there are also opportunities to compete with PVC products that weren’t available perhaps 10 years ago.

Imports have had an impact too, but “while that may close some doors, it opens doors, too. If you want to be the same and never change, changing textile technology and composites will probably put you out of business. But if you’re willing to be flexible and look at changes as opportunities, you may be changing the nature of what you’re doing and who you’re selling to,” he says. “You’re turning the gears in the back. We’re always looking for ways to turn our gears.”

What else is new?

The burgeoning wearable technology market has taken an interest in silicone coatings. “We’re seeing the first signs that they will require some sort of protection of the electronics,” Hanks says. “That’s kind of exciting.” Companies are trying to develop it now, but that’s at “the very beginnings for sensors in clothing,” he says.

Although there are new technologies in development—new polymers, for example, might potentially have an impact—market penetration would be challenging because of costs and reliability issues.

The challenge for silicon treatments is in oleophobic performance. “Resistance to oil and oil-based dirt is difficult for silicones,” he says. “Fluoros are better, but they’re being more regulated.” When silicones are wet, they get slippery, “but we’ve got ways to balance that,” he says.

APV Engineered Coatings, Akron, Ohio, has developed new formulas that will address what may be a surprising industry concern: seating materials and Americans’ love affair with blue jeans. “The dyes in denim are staining the seats!” says Erin Brown-Neff, director of marketing and business development. “It’s a huge issue.”

This is especially problematic in automotive seating. Formulations using C8 (most commonly 3M’s Scotchguard™) had the stain performance that could restrict blue jean dye. “It did perform,” says Brown-Neff. “So now without C8, the problem has resurfaced, especially in automotive and contract seating.”

“We have a lot of upholstery manufacturers who need a coating that will pass the automobile manufacturers’ blue jean dye test, have that soft, leather-like feel, will resist stains and have a low sheen or gloss,” she says. The company’s Vynguard® is a polymer technology that passes the blue jean dye test. “That’s been a game changer for us,” she says.

Automotive seating is also an important market for Alexium’s products, particularly with that industry’s growth since the recession. In the end, it’s about choices in technologies in coatings. “We have access to a lot of auxiliary treatments to use in conjunction with our FR treatments,” Valdario says. From anti-crocking technology so the color won’t rub off your jeans, to antimicrobials, “The list goes on and on,” he says. “The coaters … they make the magic happen from the finishing side.”

Janet Preus is senior editor for IFAI’s Advanced Textiles Source.