A “greener” way to make blue jeans

A “greener” way to make blue jeans

Digital laser and ozone technologies can help reduce pollution caused by denim manufacturing, said researchers.

Denim clothing enjoys popularity among consumers worldwide thanks to its versatile looks and comfort. However, traditional denim manufacturing is often associated with excessive use of water, energy and chemicals, and emission of greenhouse gases.

A new journal article by researchers based in Vietnam, Australia and India now highlights the potential of applying digital laser technology and ozone technology in denim manufacturing.

The article reflects data collected from case studies of two denim manufacturers in Vietnam and a review of existing research papers.

According to Dr Majo George, a senior lecturer at The Business School, RMIT Vietnam, laser treatment is a non-contact method that can be used in denim patterning, colour fading and surface engraving.

“Laser application is a more efficient and hygienic technique than the conventional method, with minimal environmental impact due to the virtual absence of water use,” Dr George said.

In fact, the case studies conducted by the research team found that digital laser saves a substantial amount of water (97%), energy (70-90%), and chemical cost (60-70%).

“Laser treatment requires very few consumables, such as inks, chemicals, and auxiliary materials. It reduces operating time from 30-45 minutes with the conventional method to only two minutes.

“The process not only fades the denim efficiently, but also imparts various creative effects with precision in a matter of minutes and at a reduced production cost,” Dr George added.

Stack of blue denim clothes in different shades Laser and ozone applications can support more sustainable denim manufacturing.

Meanwhile, ozone is a powerful oxidising agent that can be used to create colour fading effects and save water consumption in denim washing.

RMIT Vietnam School of Communication & Design Associate Professor Rajkishore Nayak explained that unlike conventional washing methods, ozone can remove indigo from the surface of fabric without the use of chemicals or a water bath.

No rinsing is required following the dry ozonation process, and only one or two washes are required following the wet ozonation process to remove the residual ozone and bleached indigo from denim, thereby conserving water.

“Overall, laser and ozone can reduce energy and water consumption, save a significant amount of chemicals and prevent liquid waste from getting discharged to water bodies,” he said.

However, they are currently used by only few denim companies in Vietnam due to high initial investment and labour skill requirements to operate the machines.”

Associate Professor Nayak argued that the return in investment (ROI) and benefits achieved would outweigh the initial investment.

“Several global manufacturers and suppliers of equipment for laser and ozone technologies are already present in Vietnam. Traditional denim manufacturers should implement the new technologies to make denim manufacturing more sustainable,” he said.

The sustainable fashion expert added that these technologies can also be used in the manufacturing of shoes, leatherware, and luxury fashion items that need intricated patterns and faded fabrics in the product. Laser technology has a wider application compared to ozone technology as the former can be applied to technical textiles, automotive textiles in addition to home furnishing.

Laser and ozone applications for circularity journey in denim manufacturing - A developing country perspective” was published in Q1-ranked Current Opinion in Green and Sustainable Chemistry Journal.

Story: Ngoc Hoang

  • Sustainability
  • Fashion

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