Fibre reactive dyes are synthetic low impact dyes that “react” with the fabric fibres, resulting in rich and long-lasting colour.
How do Fibre Reactive Dyes Work?
Fibre reactive dyes only work on what is known as “Cellulosic fabrics”, that basically means fabrics of a plant based origin. This includes such fabrics as hemp, cotton, linen, rayon and Tencel. The dyes can also be used on wool and some synthetics if a weak acid is introduced.
The reactive dye undergoes a chemical reaction when introduced to the fabric. This reaction physically bonds the dye atoms together with the fabric atoms so that they share an electron. This is known as “covalent bonding”.
This chemical bonding is the reason that fibre reactive dyed items are so bright and vibrant, and why they have such incredible colour-fastness. Fibre reactive dyes are known for providing long lasting colour, after years of use (with proper care) the colour will remain as rich and bright as when it was first dyed.
Are Fibre Reactive Dyes Eco-Friendly?
There are three systems of dyeing. Totally synthetic, natural and reactive. Reactive uses 90% less chemicals than fully synthetic dyeing.
All Fibre reactives – Our Dylon dyes – are free from heavy metals, chemical mordants and AZO’s (nasty compounds found in a lot of dyes). As such, these fibre reactive dyes are classified as “low impact”.
That doesn’t mean that they’re all-natural and 100% safe. They do contain hazardous compounds such as sodium carbonate, but in small enough amounts that the environmental impact is negligible. That being said, from a human health point of view do not breathe the dry powder, do not get it in your eyes or on your skin, or you’ll be in for a bad time.
So they’re not environmentally friendly? Well, let’s say they’re the most eco-friendly choice for small scale dyeing, to get the best colour-richness and colour-fastness possible. There’s a bit of a trade-off between functionality, practicality and the environmental impact. Of course if it’s 100% eco-friendliness you’re looking for, then you should not use any dye at all. Natural, undyed and unbleached fibres are the way to go. But, if you want a bit of colour in your life, and you want your dye to be as effective, long-lasting and low-impact as possible, then fibre reactive dyes are for you.
The chemical used in most fibre reactive dyes is soda ash (sodium carbonate), commonly found in laundry detergents. This is used in such small amounts that it makes a minimal environmental impact. When used in your home washing machine or hand-dyeing, the wastewater is easily broken down into non-harmful molecules by microbes in the wastewater treatment plants, and in the soil. Because of the “covalent bonding” process, most of the dye is absorbed into the fabric, meaning there is less runoff.
Salt is another ingredient used, but when diluted with waste water and drain water it is not an issue.
Fibre Reactive Dyes vs Traditional Dyes
Some traditional dyeing processes such as direct dyes, acid dyes and vat dyes have a tremendous negative environmental impact. These techniques also have negative health effects for workers that are handling them, some dyes contain, or break down into cancer causing substances like benzidine.
Traditional fabric dyes are an especially big problem in the countries where large amounts of clothing is manufactured. Indeed, across the globe, fabric dye plants are one of the most polluting technologies that exist. According to the World Bank, estimates from China say that 17-20% of all industrial water pollution is due to fabric dyes and treatments. It’s estimated that 90% of local groundwater is polluted and that 72 harmful chemicals found in the water supply result solely from fabric dyeing.
In Indonesia it has been reported that hundreds of textile factories are dumping chemicals and waste into the Citarum River, a source of drinking water for 35 million people. This pollution is linked to skin diseases, increased cancer rates and inhibited childhood mental development. For every one pound of clothing produced, 1 pound of chemicals is broken down and illegally enters the local waterways, harming wildlife and contaminating the drinking water of the local population.
Oeko-Tex 100 certified low impact fibre reactive dyes are not toxic to humans or the environment. Due to the “covalent bonding” process which occurs, the majority of the dye absorbs into the fabric, so that there’s far less runoff/waste elements than traditional direct dyes. Low impact dyeing also requires far less water as there are no nasty chemicals to flush out of the garment. It’s also possible for the water to be recycled through filtration processes, to be reused on future batches.
Fibre Reactive Dyes vs Natural Dyes
Natural dyes from plant based origins are clearly the best environmental choice, right? Well, it might not be as clear as you think. Natural dyes have several drawbacks.
A large mass of materials are required to create natural dyes, so that the material may be condensed down to a form where the pigment is strong enough to effectively dye fabrics. All of this plant material requires somewhere to grow. Phil Patterson of Colour Connections (a UK textile consultancy firm) estimates that 13 acres of land are required to dye one acre of cotton with natural dyes. Keep in mind these crops also require water, pesticides and fertilisers which can also be harmful to the environment. If you wanted to ‘grow’ the dye used in denim, a plant called woad, you would need to plant the entire land-mass of India!
Natural dyes are weaker, and not as vibrant or long-lasting as fibre reactive dyes. It would take several kilograms of natural dye to provide the same richness and vibrancy as one teaspoon of fibre reactive dye. The colour would also fade much faster.
Natural plant dyes can only be naturally fixed to the fabric on dark colours, brown, grey or black. For the lighter colours, a heavy metal ‘fixer’ would be required, rendering it non-eco-friendly – alternatively the garment must be dry cleaned, once again, not eco-friendly.
When clothes fade, consumers are more likely to get rid of the garment and purchase something new. Fibre reactive dye forms a bond with the fabric, so that the colour stays absolutely as rich as the day it was dyed. With fibre reactive dyes you can wear your clothing over and over again, so you’re more likely to keep it for longer.
Natural dyes are an excellent alternative to conventional dyes due to their non-toxic nature. Unfortunately the impact of using natural dyes at an industrial scale is simply not sustainable. This makes natural dyes a great choice for home dyeing and smaller batches, but not large scale production.
Oeko-Tex Standard 100 Certification
Dyes certified with Oeko-Tex Standard 100 are classified as “low impact”. If a product contains the “Standard 100” label, it means that the product has been independently tested for harmful substances, and is therefore harmless in human ecological terms.
To qualify for Oeko-Tex Standard 100, fibre reactive dyes must have at least a 70% rate of absorption. So at least 70% of the material is absorbed, leaving only 30% waste product. They are tested for all harmful substances according to an extensive criteria catalogue taking into account regulated and non-regulated substances.
Fibre Reactive Dyes at The Hemp Shop
We dye all clothes with eco-friendly fibre-reactive dyes. These dyes are a good example of how superior quality materials are often more ecological. These dyes are both the best quality and most environmentally-sound man made dyes available.
Because the bonding of the dye and the fibre is so strong and complete, very little residual dye comes out into the waste water when they are dyed or later into the wash water when they are used by the customer. The Swiss laboratories of Bezema developed these dyes, always keeping high environmental standards in mind. They contain no heavy metals or other known toxic substances, and they meet all European Union criteria for being an eco-friendly pigment.
Many years ago, The Hemp Shop was able to start using these dyes full-scale after working for several years to develop an effective system for dyeing with fibre-reactives. It is significantly more difficult and expensive to dye with reactive than with conventional direct dyes, but the benefits both in terms of quality and ecology make it well worthwhile. When we first started using the Dylon dyes, our boss was told by Dylon, that if a Goldfish could actually survive being tumbled around in a washing machine, that the Dylon dye inside the water in that machine, would not harm it at all.
In summary, fibre reactive dyes such as our Dylon fabric dyes do not contribute to environmental pollution, and don’t require huge amounts of land to produce. Making them a great choice for those that want to balance vivid long-lasting colours with the minimum of environmental impact.