Advanced Denim Technology - Ahead of Waterless Denim Dyeing

Posted by Sustainable Denim on Sunday, January 5, 2020 2

sustainable, denim, jeansDenim is an iconic product having versatile dynamic features that is used to make jeans and popular among people of all ages as most contemporary fashion. Every wardrobes have some pair of blue jeans made from indigo dyed denim fabric. It gives good fit, comfort and most noticeable fashion look while making a blue jeans. But the process of producing blue jeans is environmentally costly. As per report of National Geographic Magazine, 11000 liters of water is required from fiber cultivation to finishing process in washing to produce a single pair of blue jeans. Also it takes almost a pound of chemicals and significant amount of electricity.

To curb this huge consumption of resources many brands and retailers are focusing on Eco-friendly denim processing. In all around of denim processing, the dyeing steps take significant amount of water and it discharges contaminated water into nearby water body that is harmful for environment and aquatic lives.



What is the method of conventional or Traditional denim dyeing?

Conventional Denim Dyeing:

coventional denim, traditional denim dyeingIn conventional denim dyeing machine set up is longer longer with multiple machines and it likes to take almost half a mile. In this process 12-15 dyeing vats are required based on the demand of color depth and 5-7 washing bath for cleaning purposes. It is a long chain and use significant amount of water with chemicals.

indogo, moleculesIn the conventional methods, indigo dyes are used to achieve the color. Indigo dyes are not water soluble and it's dye molecules are combined with each other thus it can't be penetrated into the core of the fiber. Thus the indigo molecules are needed to be reduced by strong reducing agent Hydrogen Sulfide (H2S) and it becomes negative charges. During this period the indigo dye molecules become yellow color changing from blue and the fiber absorbs the colors. Then the dyed yarns are passed openly for next dye vats and here the molecules are oxidized by the atmospheric oxygen and turn its original blue color.
Indigo dyes help to color the fiber very slowly thus it requires more number of dyeing vats. Due to this a huge amount of waste water is generated with the contamination of Sulfide ions. Then it is passed through washing baths for cleaning and removing unfix dyes from the surface of the yarns.

What is the method of advanced denim technology?

Advanced Denim Technology:

denim, jeans, dyeingIn advanced denim technology only 3-5 dyeing vats are needed instead of 12-15 dyeing vats. In this method denims are dyed with Sulfur dyes instead of indigo. Sulfur can give quick shades to the fiber with various cast. It will give the same color as indigo gives but in different methods. Sulfur has no oxygen group but it has functional group that is called thiol (-OH).

sulfur, dye, blue, denimAt the first step, the sulfur dye molecules are reduced and give negative charges, at that time it becomes yellow color instead of blue. At the second step the dyed yarns are passed openly to the next dyeing vats and then it is oxidized by atmospheric oxygen and turned into original color. The molecules are then built link with each other with strong ionic bondage, thus the color fastness criteria improves and the jeans keep same color longer.

denim, sustainable, dyeing
This advance denim can cut the amount of water used to produce a pair of jeans by up to 92 percent while requiring up to 30 percent less energy than conventional denim manufacturing methods. Additionally, the process is claimed to generate up to 87 percent less cotton waste, which is often burned sending CO2 and other greenhouse gases into the atmosphere, and produces virtually no waste-water.

If just a quarter of the world’s jeans were dyed using the Advanced Denim process, around 2.5 billion gallons (9.46 billion liters) of water would be saved every year – enough to cover the needs of 1.7 million people annually. It would also prevent the release of 8.3 million cubic meters of wastewater, and save up to 220 million kilowatt hours of electricity.


References:
  • https://newatlas.com/advanced-denim/23023/
  • http://www.advancedenim.com/
  • https://www.archroma.com/solutions/coloration-denim-casual-wear

About the Author

Md. Firoz Kabir(M.Sc in Textile Engineering)

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2 comments:

  1. Nice post, I recommend to checkout these high quality denim which you can buy in 2020.

    ReplyDelete
  2. Nice and Informative Post.
    Denim is getting more popularity day by day.
    Hope this Blog Site will help to know more about Denim.
    Thanks.

    ReplyDelete

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