Behind The Jeans: Denim Set To Be Disrupted By Eco-Friendly Indigo Dyeing

Sonovia and PureDenim are working on a revolutionary process that reduces water and energy usage and improves product durability. 

<p>Indigo from the historical dye collection held by the Technical University of Dresden, Germany. Indigo, a dye derived from plants, has been used to color fabric for thousands of years. An Israeli-Italian collaboration is working on a way to reduce resources used in the production of dyed fabrics. (Shisha-Tom/Wikimedia Commons)</p>

Sonovia, an Israeli company specializing in eco-friendly ultrasonic textile technology, is collaborating with Italian denim manufacturer PureDenim to transform indigo dyeing.

With the novel disruptive technology, they aim to reduce the intensive use of water and energy and improve dye durability in the global denim industry — a market projected to reach $76.1 billion by 2026.

“The concept of leveraging Sonovia’s technology in indigo dyeing can truly revolutionize this industry, leading to a substantial reduction in the consumption of chemicals, water and energy and to an incredibly positive change toward eco-friendly, sustainable manufacturing,” said Gigi Caccia, founder and CEO of PureDenim.

The agreement represents Sonovia’s entry into the dyeing industry. The company’s antimicrobial ultrasonic fabric finishes are currently commercialized in products such as the Sonomask, a face mask that became popular during the pandemic.

Roy Hirsch, CBO of Ramat Gan-based Sonovia, said the collaboration with PureDenim will begin with a technological viability stage that will be completed by the middle of 2022, followed by preproduction development and the integration of the technology into PureDenim’s production line.

“Our technology can offer significant solutions to inherent challenges in the indigo dyeing industry” by eliminating outdated dyeing and finishing practices that cause massive pollution, Hirsch said.

Sonovia is an alumnus of the Fashion for Good accelerator and launched a successful IPO at the Tel-Aviv Stock Exchange in December 2020.

A worker starches cloth with an engraved stencil before dyeing it at a Chinese Blue Calico workshop on June 14, 2006, in Nantong of Jiangsu Province, China. The main process of making Blue Calico includes cloth weaving, stencil engraving, starching with a mixture of lime and soybean flour and indigo dyeing.  (China Photos/Getty Images)

Scientists have indicated that the earliest known use of indigo dyeing occurred some 6,000 years ago in the ancient Andes. Well-preserved cotton fabrics from the Preceramic site of Huaca Prieta on the northern coast of Peru holds traces of a blue pigment that has been positively identified as an indigoid dye. 

As with other similarly colored fabrics found in Asia and Latin America, the composition ratio of indirubin to indigotin — both compounds extracted from indigo plants — in these fabrics leans heavily toward indirubin, unlike the ratio found in dyed European fabrics. Researchers studying the fabric have suggested that “ancient vat dyeing technologies favored the formation and uptake by the yarn of indirubin. This would have resulted in a more purplish hue produced by a reddish indirubin and a bluish indigotin.” 

The researchers believe that the source of the indigoid dye at Huaca Prieta is most likely the Indigofera spp. But other indigo-producing plants native to South America are being grown today to produce the dye, including Justicia colorifera (cuaja tinta or tinta montes), Koanophyllon tinctorium Arruda and Cybistax antisyphilitica Martius (yangua).

The dye process is quite labor and resource intensive, requiring several dips in the dye to deepen the color and a significant amount of water to wash out the excess dye before the fabric is exposed to the air to set the color.

Produced in association with ISRAEL21c.

Edited by Siân Speakman and Matthew B. Hall