FOAM FINISHING

Foam applications are an answer to an environmental dilemma, since they use more air than water as a vehicle to carry chemistry to the fabric at very low wet pick-ups, in some cases less than 30%, for some finish applications, less than 10%. And because of the very low wet pickups possible, less chemistry is needed; you calculate the wet pick-up and apply only what you need. And it’s a very flexible system that can apply dye to one or both sides of the fabric—if it will foam, it can be applied. If the fabric is not as wet, it will dry faster, lowering energy costs and increasing productivity. Jerry Morgan, project manager, Gaston Systems, the firm that developed this innovative system, comments, “You’re using less water, you’re not discharging nearly as much into drains, and you don’t have as much to clean up. It’s really good to be able to conserve the environment.” The system is now used in more than 20 countries, and is making a huge difference in water conservation.

LOW-LIQUOR DYEING

Conventional dyeing technology uses large amounts of water to transport the fabric through the process of imparting dye to cloth. Fong Industries uses a revolutionary technology that uses air to move the fabric. Tony Jones, sales representative for Fong, explains: “If you use air to transport it, then you only need the water for the actual dyeing, for the actual application of the color. So this helps significantly reduce the amount of water used. A great example is that using conventional dyeing methods and machinery, it takes over 200 liters of water to dye a single T-shirt. But by using air technology and air-flow machines, you can do it for as little as 50 liters per T-shirt. That’s a really substantial improvement. It also means reducing energy consumption, reducing chemicals used. That’s the key—any way you can remove water from that process, you’ll reduce that environmental impact.”

CONTINUOUS TWO-STAGE BLEACHING

Traditional 3-stage bleaching involves desizing, scouring and bleaching, but this new technology combines the desizing and scouring stages in one step. That’s not all: It significantly reduces the number of wash boxes following both the desize and the bleach. Water and energy use are reduced by more than 60%, since there’s less hot rinsing and less time in the steamer, which translates into higher productivity. And there’s comparable whiteness and fabric strength to conventional preparation of the fabric. Cotton Incorporated worked with Innova International and its president, Angelo Rizzardi, inventor of the process, in the very early development stages, using its expertise, labs and equipment to optimize the process. Rizzardi comments, “Of the water used in textiles, 80% to 85% is consumed in wet processing, so it needs to be addressed if we want sustainability in the textile industry. We may end up saving probably 70% or more of water that currently is wasted or used in the rinsing operation. A similar amount of energy will no longer be necessary to heat water to the necessary temperature.”

DIGITAL PRINTING

Printing fabrics with conventional dyestuffs is a major user of water energy and chemicals, but digital printing is a low-consuming alternative. There are no nickel screens, no screen emulsion, and no wasted unused dye in screen or in bulk to dispose of after printing. A small amount of dye is used, so little comes out in washing, especially compared with conventional reactive printing. Engineered prints can further reduce dye usage. The other benefits: Digital printing shortens the overall process from design to production, since there’s no engraving. Multiple colors and mass customization are possible (although pearl and metallic aren’t yet available). Downtime and waste are minimized, and labor requirements are low. David Clark, technical representative for the Swiss company Hunstman (a leading supplier of digital-printing dyes), notes, “You can print whatever’s on your computer screen. Digital printing wastes nothing, fabric or ink, and it doesn’t use harmful solvents. From an environmental perspective, digital printing has a significantly smaller footprint per yard of fabric printed.”

OZONE BLEACHING

When you think “ozone” you might think “water purification,” but in textiles, ozone has found other niches. In addition to low-temperature disinfection in commercial laundries, ozone is used in garment washing processes to reduce chemicals used to achieve wash-down looks, and to decolorize waste water, so that any dye going into the effluent stream is decolorized before discharge. Ozone is an appealing technology to explore because as a powerful oxidizer it works very quickly; it uses significantly less water than some conventional garment washing processes; it works best in a chemical free bath; and it’s effective at room temperature. Says Len Farias, senior textile chemist at Cotton Incorporated, “We’ve been using ozone technology to process cotton fabrics. We can get a very similar wash-down effect as we could with bleach, stones or even enzymes. Ozone is environmentally benign: There are no chemicals involved other than the ozone, and when it decomposes it turns back to free oxygen, which is very environmentally friendly.”

LOW-SALT REACTIVE DYEING

Huntsman, in addition to being a leader in digital printing inks, has a company-wide goal to identify every possible way to minimize the environmental impact of its dyes. Says Mimi Cartee, product manager and chemist at Huntsman, “One of our biggest innovations that we launched a few years ago was our low-salt reactive dye platform, a process that uses much less salt. Imagine one textile mill process that would use nearly a whole palette of salt, 400 to 500 pounds. We’ve been able to drastically reduce that amount of salt down to two bags. Roughly a twenty fold decrease in salt usage. And this is salt that would ultimately end up going into the waste stream.”

ENZYME FINISHING

Danish firm Novozymes, the world’s largest producer of industrial enzymes, is the source of the proteins being used by Vijayeswari Textiles in the south of India to replace high-alkaline chemicals in the scouring process. Says R. Parameswaran, Vijayeswari’s general manager, “Previously, we were using harsh chemicals to remove impurities from the fiber, or from the fabric. We started using enzymes which have given us a good result compared to the feel of the fabric, and also the output of the effluent.” Adds Dr. Claus Pedersen, director of sustainability at Novozymes, “You can reduce energy consumption, water consumption and chemical consumption. So introducing enzymes means reducing the environmental impact and making a much better business at the same time.”

KALTEX'S WATER TREATMENT

Waste water is a major concern everywhere, especially in developing countries, and Kaltex, the largest textile company in Latin America, is a clear example how best to deal with it. Besides fulfilling ISO 14000 and ISO 9001 certifications, Kaltex maintains a sustainability policy in all of its enterprises and processes. This effort includes an important and constant improvement of the water quality of its plants at San Juan del Río, Mexico, with a waste-water treatment facility that is a model of environmental correctness, treating and cleaning nearly 480 liters of water every second through physical and biological technology. The Kaltex water treatment system is one of the largest of its kind, with fully automated-controlled equipment for water recycling, water treatment, and even watering the gardens, for three fabric finishing plants, an entire denim plant and two garment-finishing laundries.

LUCKY TEXTILES' DENIM MILL

Mainland China is the location of a new and innovative denim mill. Lucky Textiles recently completed the facility, the size of 11 football fields, with the environment in mind. Illuminated largely with natural light, it’s operated by a computer-controlled nerve center connected with all of the mill’s operations. Combined with an auto-dosing unit in dyeing machines, Lucky can accurately use fewer chemicals and dyestuffs without waste. Less chemical remains on the fabric, so there’s less need for washing, which reduces the impact on the state-of- the-art water-treatment. Lucky even built a new canal for the facility and the operation is connected with the local Environment Protection Bureau, which can monitor the quality of Lucky’s waste-water system in real time. In the weaving area, the latest in warping and high-speed weaving is used, and stray fibers and waste in the air are captured, making for a very clean working environment.