Explaining Low Impact Dyes

Amanda Cattermole

BY: Amanda Cattermole / 30th Jun

According to OekoTex Standard 100, low-impact dyes are dyes that are classified by the Oeko-Tex Standard 100 as eco-friendly.

Low impact dyes do not contain toxic chemicals or mordants (which fix the dye to the fabric), require less rinsing and have a high absorption rate in the fabric (~70%).

Most dyes require water and energy to work. Most dyes also work in the presence of auxiliary chemicals such as salt, soda ash, acids, leveling agents etc. The specific chemicals are dependent on the type of dye and the type of fabric being dyed.

As pollution in the textile industry has come under more scrutiny, chemical companies, brands and manufacturers have been innovating and marketing through a sustainability lens.

Chemical companies have focused on the specific dye itself, and how that dye is applied to the fabric. Dyeing has an enormous impact on the overall environmental footprint of textile manufacturing.

Let’s break down the definition a little further to fully understand what low impact dyes are and how they cause less pollution when compared to their conventional counterparts. The four areas below make up the definition of low impact dyes and each should be considered carefully.

Dye toxicity

The toxicity of a dye considers the structure of the dye rather than the dyeing process. Dyes that contain heavy metals and carcinogens should be avoided. Dyes that cause allergic reactions are NOT considered low impact.

Dyes that pass eco standards such as bluesign, GOTS, OekoTex 100 and Cradle to Cradle and are compliant to the ZDHC MRSL have been assessed thoroughly for toxicity and should be chosen over dyes that have not.

Dye manufacturers will tell their suppliers if their dyes pass these standards.

Resources: Water and energy in the dyeing process

Processing textiles requires lots of water and lots of energy to heat that water. Dyes typically dissolve in hot water and are transferred onto the fabric in the presence of chemicals.

Water is used to wash, bleach and prepare the fabric for dyeing and it is used to clean and rinse the fabric after dyeing.

Low impact dyes work with much less water, require less rinsing and often work at lower temperatures.

Reducing water and energy has a positive impact on the bottom line and a significantly lower environmental footprint.

Auxiliary chemical loading

Dyes work under certain conditions. Reactive dyes require salt to help them be attracted to cotton and alkali to fix them permanently onto the fabric. Leveling agents and wetting agents are used in the dye process as well.

Low impact dyes are designed to work with significantly less salt and alkali such as soda ash. These chemicals have a negative impact on water effluent, mostly due to the huge amount required during dyeing. High salinity at a high pH is not good for fresh water ecosystems.

Absorption rates (waste)

One of the problems with dyeing is that not all of the dye reacts with the textile, which means that a lot of unreacted dyestuff goes down the drain in the form of waste. In some cases only 50 to70% of the dye actually stays on the fabric. The rest is wasted.

Low impact dyes have high absorption rates, meaning that 80 to 90% of the dye remains on the fabric.

By working with high quality dyes made by chemical companies that focus on sustainability, there are plenty of low impact dyes available in the marketplace today.

Amanda Cattermole

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