Laundry/Wet Finishing New Chemicals, Environmental Issues Drive Development
By JOHN MCCURRY
In the laundry and wet processing arena, three primary issues are at the forefront: 1) textured fabrics still rule the day, and U.S. textile mills are continuing to refine their finishing processes to deliver these goods to consumers; 2) new and improved chemicals, dyes and specialty finishes are allowing manufacturers to produce a wider array of performance fabrics; and 3) environmental issues, such as water conservancy, are playing an increasing role in fabric finishing.
Indeed, strict environmental regulations coupled with technological advances and development of new fibers are likely to support continued development of new processing systems and chemicals in coming years. More and more, textile mills will rely on expertise from chemical companies in dyeing and finishing. A recent study by The Freedonia Group, a leading consulting firm, asserts that value-added finishing chemicals will be among the fastest-growing product categories. Freedonia says there will be considerable opportunities for softeners and hand modifiers in production of comfortable, low-maintenance apparel and home furnishings.
Meanwhile, U.S. textile companies with finishing operations are calling on a variety of resources as they seek to remain competitive in today's tumultuous global industry. The latest technology, processing expertise and a keen eye on fashion trends are among the prerequisites.
"We emphasize the character of each fabric," says David Mitchell, director of wet processing and line development for Mount Vernon Mills, one of the largest vertical fabric weavers in the United States. "The greatest characteristic of a particular fabric may be the great hand it provides. Whatever you do with this fabric in the laundry, you want to preserve that quality. The same is true for colorfastness. On a stay-true black, you don't want to be aggressive and lose what you have spent so much time in developing. On the other side of the fence, with some of the textured fabrics, we push the extremes of [the fabrics'] performance abilities with destructive washes for the really worn look."
Mitchell says that while he has heard from some sources that the tinting or "dirty denim" look maybe losing steam, he thinks the trend will evolve into the use of colors such as reds and greens in addition to earthy shades, which have been popular in recent years.
Doug McBurney, who heads textile manufacturing for Russell Corp.'s Alexander City, AL, operations, says one of the most significant trends is the continuing improvement of batch dyeing technology, which has considerable environmental ramifications. He cites the steady decline of liquor ratio (the ratio of water in units of pounds to pounds of fabric being dyed) through the years from 20:1 down to the current 3:1.
"Reduction in water volume results in a significant reduction in energy, auxiliary chemicals and dyestuff to produce the desired shade," McBurney says. "In some cases the transport medium for the fabric in the dye bath is now air instead of water. Dyeing with air is proven technology today."
Process control developments have made for further improvements. McBurney says that computer-based dyeing systems have resulted in an increase in "right first time" production, increased productivity, source reduction of pollutants and more precise and repeatable color creation.
"While the fundamentals of aqueous dyeing systems have not changed since the introduction of synthetic dyes in the mid-1800s, the process that is used has definitely entered the computer age," McBurney says.
Specialty finishes give mills many more options for product diversity today, McBurney continues. Finishes that provide stain repellency, stain release, water repellency and anti-microbial properties are now common in men's and women's apparel.
"In the past, these properties would only be found in niche products like rainwear or other outerwear items," McBurney says. "This trend is due to the development work carried out by the specialty chemical manufacturers. These finishes used in conjunction with the relatively new microfibers that are available have resulted in unique and desirable fabrics for many applications."
While Mount Vernon's mammoth Trion, GA, finishing plant sits atop a vast underground aquifer, providing the company with almost unlimited water, it has made great efforts to limit its use of water in its finishing processes.
"Everyone is cutting to the lowest water levels in processing possible that will still give good-looking quality garments," Mitchell says. "One of the first steps toward this goal was the development of acid desizing agents on the market. This allows you to desize garments and then add an acid cellulose to this bath and essentially desize and enzyme stonewash all in one bath without draining or rinsing. Many of our customers have been doing this in production for years. Some have even shared their plans to reclaim and re-use some of their water."
Following is a closer look at some of the new machinery, chemicals and other solutions that are enabling new possibilities in laundry and wet finishing.
Italian finishing machinery manufacturer Sperotto Rimar is among the innovators in developing products to limit water use. The company has made recent developments to its Nova 220/600 special continuous open-width solvent scouring range for knit fabrics. The company says solvent processing allows for considerable savings and better control of drying conditions, leading to better evaporation efficiency. In keeping with its environmentally friendly theme, the machine has no exhaust chimney. Air and gasses are re-circulated in a closed-loop operation and kept clean by active charcoal filters that absorb and recover the gas phase.
Biancalani, another major name among Italian textile finishing machinery manufacturers, has enhanced its Airo finishing machine. This machine enables preparation, washing, softening, special treatments with soda and enzymes, as well as squeezing, drying and cooling the whole range of natural and synthetic fabrics for a wide variety of applications, including men's wear and women's wear. The company has about 50 machines at customer locations in China working on silk. Most of its U.S. installations are dedicated to softening upholstery and decorative goods, while in South America, Airo machines are used to enhance fibers such as Lyocell and linen. In Italy, many finishers use the machines to increase drape and elasticity of fashion- oriented goods for stylists.
Biancalani's most recent development is the Spyra machine, which combines drying, softening, shrinking and bulking treatments. Among apparel applications, the machine adds dimensional stability to knitted goods. Spyra also may be used to impart soft-hand effects to sueded cotton wovens, pigment printed goods and worsted wool. Biancalani reports that Spyra can achieve the same results as conventional discontinuous tumblers without their typical problems, such as knots, streaks, torsions and width unevenness.
Morrison Textile Machinery's new Micro-Sat bleach saturator is for high chemical pickup applications. Micro-Sat features a horizontal three-roll nip assembly consisting of a rubber-covered squeeze roll, stainless steel center roll and urethane-covered micro-adjustable gap roll. Micro-Sat, unlike some other low-volume, high-wet add-on devices, includes small swirl tanks with mixers prior to the immersion troughs, which allow some reaction time between the caustic, stabilizer and hydrogen peroxide prior to fabric contact.
Milnor has introduced a new 75-pound to 80-pound (34 kg to 36 kg) capacity washer-extractor. The 36021 V5J offers a high extraction rate (excellent for all-cotton goods) and easy-to-use controls, the company reports. This is the latest model in Milnor's V-Series line of washer-extractors, with capacities ranging in size from 35 pounds to 140 pounds (16 kg to 63 kg). The 36021 V5J has a rugged structure and proven drive system, according to the company. The microprocessor controls have self-diagnostics to help solve problems, which helps to make laundries more efficient. This machine uses water and fuel efficiently to minimize expenses and also fits through a standard 48-inch doorframe for easy installation, Milnor reports.
Apollo Chemical of Burlington, NC, recently introduced new patent-pending technology in the area of moisture modifiers. Apollo's Aquatek Uno product is a durable modifier that imparts hydrophilicity to nylon 6 and nylon 6,6 fabric. Apollo reports that Aquatek Uno provides absorbency, vertical wicking and moisture transport to nylon fabric, and adds that nylon fabrics treated with the product have a quicker evaporation rate than typical nylon fabric.
Other benefits of Aquatek Uno are a soft hand and reduction of static buildup while enhancing soil release properties during home laundry, says Betty Tilley, Apollo's product manager for dyeing and finishing.
JOHN MCCURRY is an Atlanta, GA-based free-lance writer and editor specializing in textile and apparel issues.