Textile Insight

textileinsight.com November/December 2022 ~ Textile Insight • 17 multi-twist, and OE slub yarns that imparted vintage aesthetics to mass-produced denim. Immersion in indigo At the heart of denim is indigo, from the plant indigofera tictoria, which functions more like a pigment than dyestuff. Insoluble in water, indigo requires a chemical reaction to create a vat of dye. Cotton for the denim warp is dyed in "ropes" consisting of hundreds of yarns, dipped and oxygenated multiple times to create various depths of shade. Ring-dyed denim yarns are characterized by a white core; the indigo sits on the surface of the cotton fiber, where it flakes away or abrades to create denim's characteristic irregularities. Synthetic indigo dyes based on aniline were invented in the 1890s, and in 1921 the White Oak mill invented and patented the Touchstone continuous rope dye process for indigo. e process was faster, less expensive, and more consistent than older methods, and is standard use for dyeing commercial denim today. Proximity Manufacturing Company Cone Mills was one of the first to use American-made Draper X3 shuttle looms to weave selvage denim, characterized by an iconic contrasting warp thread along the woven edge of the fabric. In 2004 Cone Mills became part of International Textile Group (renamed Elevate Textiles), which moved the business overseas. e closure of the White Oak Mill saw the remaining 45+ Draper looms sold off. With its two rebuilt Draper looms housed at the White Oak Mill, Proximity Manufacturing Company is again weaving selvage denim using American-grown, ring-spun cotton that is roped, dyed, slashed, and beamed at Mount Vernon Mills in Trion, Georgia. e denim is a 3x1 right-hand twill, finishing at about 12 ounces/sq.yd. e new Proximity denim is sold raw or "loomstate," which means it has not been Sanforized or pre-shrunk, reducing its environmental impact. Current partner brands include Tellason, Runabout Goods, and Raleigh Denim Workshop. Sustainability Is Driving Innovation Like most textile manufacturing, today's denim is cleaning up its act. Certification of cotton provenance, chemical and wastewater management, and improved dyeing techniques are becoming basic requirements for global companies such as Cone Mills. Dennis Scheer, director of innovation for WOLF and former director of finishing innovation for VF Corporation, described newly sustainable alternatives for denim dyeing and garment processing, including pre-reduced indigo, indigo alternatives, and laser finishing. "Laser finishing is one of the greatest things the industry's done," he told the class. CleanKore is a patented technology for indigo dyeing that leaves a bright white core in the yarn, reducing the time for processing via lasering, washing, or abrading, and eliminating the use of chemicals such as potassium permanganate. Natural Core Yarn is a non-indigo technology for garment dyeing. e warp yarn is chemically modified to accept cationic dyes, leaving a natural core; then woven with non-cationic cotton yarns in the we, which remain undyed. e dyed result is a non-indigo denim or other fabric in any color which can be finished with fading, lasering, or stonewashing. The Future of Selvage Denim arpe's focus is now on IndigoZERO, a type of foam dyeing without a dyebath or wastewater discharge. e process is not only more sustainable, with better color fastness, but faster and less costly. arpe calls the ability to build a small machine that quickly foam dyes one 400 thread section beam at a time "a breakthrough that could supply White Oak's Draper looms, and bring indigo dyeing back to North Carolina." In August WOLF announced the launch of a denim design and development lab, White Oak 3.0, which will be housed at the White Oak Mill. In cooperation with global partner Jeanologia, the developer of laser-finishing for textiles, the project will promote fast prototyping and small batch production. Bob Stec called the endeavor "a passion project, run by people who believe that the future is tied into the past." As WOLF continues to expand its efforts in innovation, manufacturing, historic preservation, and education, Denim 101 classes for 2023 will be held on March 21-22 and September 26-27. n Just one of an infinite number of shades of indigo.

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