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When researchers at Cotton Incorporated World Headquarters look to expand the potential of new technologies, their work often goes far beyond testing a particular piece of equipment. While there are those proprietary developments that might prove especially useful to the industry, the most important projects generally offer new ideas for using readily available equipment and supplies that can help improve productivity and quality.
What Mary Ankeny, Manager of Textile Chemistry Research, is now doing with digital printing certainly reflects this universally useful approach. She, in fact, emphasizes that it's not really about the specific digital printer recently purchased by Cotton Incorporated, but exploring the possibilities of this burgeoning technology.
“A major consideration was choosing a printer equipped with an ink delivery system called Piezo,” Ankeny explains. “Instead of using heat to force the ink or dye out, it relies on an electro–potential charge that moves a piece of metal which moves the ink onto the surface to be printed. This allows us to use all of the different dyestuffs for cotton. When you consider pigment dyes, for instance, the new method involves printing the dye and binder together. If you were to heat this solution, you'd have a real mess on your hands,” she says.
In fact, experimentation with pigment dyes is an important direction for Ankeny's digital printing research.
“The big advantage is that these new dyes don't form a stiff film on the printed fabric, so the hand is softer. When pigment dyes are used in the digital printer, you don't have to pre–treat, steam or after–wash, as you do with reactive disperse and acid dyes,” Ankeny says. “Advancements in pigment dyes for digital printing has led to a nice range of colors, which were originally limited to pastels. The availability of jewel tones and other darker colors is giving digital printing a boost. The question now,” she adds, “concerns the durability of these new dyes.
“Evaluation of pre– and post–treatments for improved dye fixation is our current developmental focus with regard to digital printing,” Ankeny notes. “For example, we have been working with different pre–treatments that will enable us to print on cotton fabric with acid dyes.”
In addition to using different dyes in the digital printer, Ankeny is experimenting with different fabric constructions. “Digital printing was initially limited to wovens,” she notes. “We have been running knits smoothly with minimal stretching in the machine. We have also been testing sliver knits, non–wovens and even velvet. By adjusting the distance between the print head and the fabric roller, we have been fairly successful.”
By working directly with several mills, Ankeny is using digital printing technology for realistic applications. “Different companies are sending us digital files of prints they are currently using. We can pull them up, and give everyone from designers to production managers an idea about how their designs will look on different substrates,” she says. “We have also been working with our New York office to create fabrics for the ‘Cotton Characters’ used as models in our print advertisements. The folks in New York send us prints they are interested in using, and we can scan, reduce, and clean them up and then show the re–sized pattern printed on 100% cotton fabrics.”
Ankeny is hardly new to application research. After earning a BS in Textile Engineering from Philadelphia University, followed by an MS in Textile Technology from the Institute of Textile Technology in Charlottesville, VA, Ankeny went to work for Amoco Fabrics and Fibers (now BP) in Atlanta. “I worked as a Research Engineer in the Nonwovens Group,” she recounts. “My most memorable project concerned the development of 'housewrap,' a breathable substrate that goes under the siding. I spent many a cold winter in Green Bay, WI, working on that one,” she remembers with a shiver.
Perhaps it was the warmer North Carolina sun that led her to join Cotton Incorporated in 1995 as Manager of Dyeing and Finishing Technical Services. Her title recently changed to Manager Textile Chemistry Research, with a primary focus on printing, garment dyeing and enzyme treatments. “I recently published a paper entitled 'Single Bath Dyeing and Bio–Polishing,' to assist mills in taking advantage of the enzyme process without adding more time to their dye procedures,” she says.
Ankeny's two sons, one just three and the other still an infant, keep her and her husband Jim quite busy when she's not in the lab. “After working at Cotton Incorporated for seven years, I can say with confidence that there is virtually no stain the boys can create that I can't handle,” she quips.
But it's digital printing that remains the prominent focus at work. “The possibilities seem unlimited. Even the most sophisticated screen printers are limited to 16 colors and it takes a long time to set up or change patterns and designs,” she emphasizes. “With digital printing, I can quickly download a huge variety of digital fonts and even photo files, which can be modified in innumerable ways. I can even print several colorways or several patterns side by side.”
The digital printer presently used at Cotton Incorporated, the Mimaki TX 1600S, is both small and affordable, but printing speed is limited to one
yard an hour. “This is good for small–scale runs as well as to review preliminary designs,” Ankeny says. “And in the future, we'll be seeing prices come down on faster and larger machines. Right now there are machines printing up to 60 yards an hour.”
This represents huge potential for everything from haute couture to activewear, she adds, as printed looks are increasingly in demand. |
