Globally, the textile sector is the second most polluting industry. With about 20 percent of world water contamination connected to the textile dyeing operations, synthetic colors play a big role in this pollution. The major causes of this issue are the use of hazardous agents to fix colorants on the textiles, the use of non-biodegradable petroleum-based colorants to dye textiles, and the leakage of significant volumes of these colorants and fixation agents into the near by ecology. China closed most of the enterprises manufacturing synthetic textile colors a year ago after strict new laws passed. Following such closures and stringent environmental rules,businesses are now investigating greener methods of coloring clothing. Natural colors derived from biodegradable plant sources are a good substitute for manufactured colorants. Still,hazardous fixing agents should be used with these colorants. The fashion and textile sectors together are looking for different coloring techniques currently. These are some of the less harmful methods creative businesses are using to color clothing.
Pigments featuring a hybrid composition:
Ecofoot has made hybrid colors that are made up of a dye chemically connected to a polymer particle that can react with cellulose fibers at temperatures as low as 25ºC. This process does not call for salt, which is normally essential to push the color into the cloth. This method may be used in a more environmentally friendly manner for wool as well as for low temperature dyeing of cotton clothing. Usually used in converting indigo pigment to a water soluble state, ecofoot-indigo is a hybrid pigment used in dyeing denim without using harmful reduction chemicals. Common reducing agents are regarded as ecologically bad as the sulfite and sulfate produced in the dyebath might create different issues when dumped into the wastewater
Usually requiring severe washing-off processes to remove the hydrolysed dye, Ecofoot also developed auxiliaries to avoid hydrolysis of the dye in the dyeing process. More than half of the water in the intermediate and final rinses may be conserved throughout the whole preparation and dyeing process along with hybrid colors and auxiliaries.
Textile fiber-based powder dyes:
Using recycled clothes, fiber material, and span textile wastes, Italy-based business Officina+39 created the sustainable dye line Recycrom. It created a clever eight-step procedure (patent pending) wherein all the fabric fibers are crystalized into an incredibly tiny powder fit for use as a pigment dye for cotton, wool, nylon, or any natural fiber. The textiles may be treated with recycled chromium via exhaustion dyeing, dipping, spraying, screen printing, and coating among other techniques. While most dyes are used as a chemical solution and so can be readily filtered from water, recycrom is utilized as a suspension and so reduces the environmental effect.
Pretreatment for cotton calls for more water than that of other fabrics for dying. One kilogramme of cloth needs over 200 liters of water. Before the dyeing process, Dow has created a pretreatment method called ECOFAST Pure to create cationic cotton. The pretreated cotton gains a persistent positive charge which increases its attraction for negatively charged chemicals like dyes. For cotton dying, this innovative process reduces dye and water usage by half. Using a solution including a wetting agent, caustic soda, and ammonium salt, ColorZen has developed a technique for pretreatment of raw cotton fibers. With out the necessity of fixation chemicals, this pretreated cotton shows higher capacity to hold the dye, therefore lowering the use of harmful chemicals by 95 percent and water waste by 90 percent.
Microorganisms native or engineered:
Colourifix uses synthetic biological techniques to colour the fabrics using bacteria, therefore saving up to ten times the water use. This procedure uses creative processes wherein the dye-producing bacteria are straight onto the fabric using a carbon supply solution, then deposited and fixed onto textiles with a single heating cycle by lysis of the microorganisms.
This method does not call for fixing and reducing agents including organic compounds or a color extraction procedure using organic solvents . Using genetically engineered E.colibacteria, University of California researchers are creating denim dyes that generate indican which with enzymatic treatment may subsequently make indigo. This innovative method replaces an enzyme with strong chemical reducing agents for indigo dye solubilization, therefore eliminating their demand. For its sustainability, the procedure still requires improvement in the recovery of indican however.
Creative dye and auxiliary materials:
Unlike the traditional reactive dyes, Huntman Textile Effects developed Avitera, a series of polyreactive dyes for cotton that easily bonds to fiber, using creative dye and auxiliary technologies. With cellulosic fiber, avitera dyes provide a high reaction and fixing rate using tri-functional chemical reactivity , therefore leaving very little unfixed dye to be removed. By up to 50% this drastically lowers water and energy use as well as salt use. Also recently developed by Huntsman Corporation is the diffusion accelerant Univadine E3-3D, a dyeing auxiliary enhancing color dispersion into polyester. This diffusion accelerant is devoid of harmful chemicals and touted to produce high-performance dyeing of polyester microfibers, therefore conforming with existing and expected industry sustainability requirements.
Printing digitally:
Intech Digital presented a novel “waterless” textile printing process to give colors utilizing Blackjet reactive pigment textile inks (nanopigment ink). Unlike a dye, blackjet textile inks employ a pigment that is insoluble in the ink carrier and include resin binders to let the pigment particles cling to the cloth. Following a post-treatment phase, this method employs a four-step process including a fabric pretreatment, digital printing with reactive pigment inks, and fabric heating for attaching the pigment onto the fabric. To produce high-level results in digital printing, DuPont Artistri digital textile inks are developed using colors and dyes similar to those used in traditional textile printing
Upcoming Challenges:
Although these developments are very promising and ecologically benign, numerous obstacles still have to be broken through. Given the textile sector is a manufacturing sector under pressure, there is fierce rivalry for garment costs. The creative innovations underlined here still need further improvement in terms of low-cost manufacturing and commercial feasibility while satisfying consumer needs. Rising raw-material costs make it somewhat difficult for producers to create a completed garment in a sustainable manner without driving prices over what customers are ready to pay.
