“Quite a bit of work has been invested in modernizing the denim dyeing and finishing industry over the last 25 years,” said Mary Ankeny, Cotton Incorporated’s VP, product development and implementation operations, textile chemistry research. “I’m actually not sure if any other segment of the textile industry has benefited as much from technological advancements as denim garment finishing.”
This surge of innovation is the catalyst for alternatives to conventional denim, including dye techniques offering more sustainable and unique attributes.
In a webinar last week, Ankeny and Kristie Rhodes, Cotton Incorporated manager, woven product development, shared how jeanswear manufacturers can rethink how traditional denim gets colored.
Cotton develops a slightly negative charge when it is immersed in water. Unfortunately, most dyes also have a negative charge in water, meaning makers must add salt to move the dyes from the bath to the cotton fiber. “A cationic treatment can impart a permanent positive charge to cotton, eliminating the need for salt in the dyebath. Another benefit to this application is that the cotton can attract and hold virtually all the dye in the dye bath, so no dye goes down the drain unless dye is needed to create the same shade as compared to a conventional fabric,” Ankeny said.
Cationic treated cotton yarn can mimic interesting yarn-dyed looks in cotton, piece dyed, and garment dyed fabrics, Rhodes noted. “You can have one fabric and dye it many different colors with a yarn dye effect,” she said.
Cotton Incorporated has been experimenting with natural dyes with Seattle-based dye supplier, Botanical Colors. Namely, they’ve been working with dyes derived from logwood and food-grade ferrous sulfate iron.
“Historically, natural dyes did not have a great fastness to wash,” Rhodes said. “Advancements have been made to the dye stuff and the auxiliary components for the dyeing process to improve fastness property.”
Though synthetic dyes tend to be more predictable as far as their fastness properties, Rhodes said the denim industry has begun to accept the tradeoff of natural dyes as a sustainable story over their variable fastness.
Innovations in the natural dye space are ongoing, however. Rhodes named Stony Creek Colors as playing an “important role” in scaling natural indigo for denim. For untraditional denim colors, Tonello’s Wake technology uses plant and vegetable waste including flowers, berries and roots to dye fabrics without harmful chemical additives.
Cotton Incorporated has also tested Officina+39’s Recycrom, a patent-pending pigment dye stuff made from fabric textile waste, on canvas and traditional twill. “The dyes can be applied via garment dyeing, garment dip and screen printing,” Rhodes said.
Digital printing is a hot topic, but Rhodes said some question if the technique is a viable solution for denim jeans. Is it just scanning in a pair of jeans and printing a pattern onto the fabric of your choice? Does it matter that it won’t fade down like a true indigo?
“Of course, most [people] in the denim textile or garment industry know that it is not that simple,” she said. “Some variation of a digital jean will happen with a lot of engineering on the digital printing and cut-and-sew side behind it, but will it satiate the entire jeans market?”
Outside of trying to print a realistic indigo-looking jean, printed denim is a great option, she added.
“Any imagery that you create can be printed onto a denim base and combined with other technologies such as laser and ozone for amazing effects,” she said. “Digitally printing with reactive dyes or pigments offers a wide range of looks that can be individualized.”
Raw Denim and Natural Denim
Another option is to not finish denim at all.
“Let’s just wear it like it is and have it [age] over time,” Rhodes said, noting that raw denim was the only option as a kid growing up in the ’70s and ’80s.
For the denim purist or denim head, having jeans wear down naturally and fade over time with little to no washing is the preferred style, but Rhodes questions raw denim’s mass appeal.
“It’s a different way of looking at things,” she said. “I’m not sure if the general population can get behind not washing their denim or at least not as much but this is another option.”