Why solution dyeing is ‘dope’

Why solution dyeing is ‘dope’

We go into the mountains to find somewhere wild. A place where honesty speaks louder than bravado, and where boasts falls on deaf ears. Producing garments might seem a million miles from the mountains, but we are trying to bring the same honesty we portray in the mountains to our actions back in the office. That means writing about the things our industry does badly. Just because these discussions aren’t easy doesn’t mean they’re not important. Pressure us, pressure your retailers, force something good to happen.

Sustainability discussions are everywhere. Carbon dioxide emissions are measured and deliberated over, water use is analysed, and workers’ rights are increasingly under the media spotlight. But chemistry is completely forgotten about. Chemistry isn’t just Bunsen burners, test tubes, and blowing stuff up: why is your fleece orange, why does your jacket bead water, and why can your t-shirt resist odour? There’s a lot of chemistry in your average outdoor product, and a lot of it isn’t exactly sustainable. Dyeing is one of the dirtiest industries there is and no one ever talks about it.

The problems with dyeing

Dyeing is what colours your garment. There are thousands of different dyes and dozens of different dyeing processes, chosen depending on the fibre you are colouring and what the intended use is, but many if not all of the most commonly-used dyeing processes have serious environmental downsides, from huge uses of energy, water, acids, alkalis, and bleaches, to releasing toxic wastewater, and the environmental impact of the dyes themselves. Dyeing is often exceptionally inefficient, with sometimes less than 10% of the dyestuff actually ending up on the garment being dyed. Where might the remaining 90% go? A fifth of the world’s industrial pollution is due to textile dyeing. 

Traditional textile dyeing method

Solution dyeing

But, alternative dyeing technologies do exist. One of these is solution dyeing, also known as dope dyeing or spin dyeing. Conventional dyeing colours fibres once they have been extruded. With most conventional dyeing processes, undyed fibres are put in a big trough of dyestuff and additives and are coloured as they sit in it. The process is woefully inefficient and hasn’t changed significantly in decades. In solution dyeing, the dye is added to the polymer solution from which the fibres are made, so when the fibres are extruded they come out coloured. This is much more efficient and completely bypasses a step of processing. It significantly reduces water use in the dyeing process, it reduces energy use and subsequent greenhouse gas emissions, and vastly reduces the amount of dyestuff and fixing agents required. It also makes for a more durable colour: think of a piece of granite as being solution dyed and so the same colour throughout its bulk, whereas conventional dyeing is like a block of limestone covered in lichen where the outside of the rock is coloured but the inside of the rock is not. 

Solution dyeing

Why isn’t dope dyeing used more widely? The biggest reasons are scale and the difficulty in high quality dope dyeing. 

Scale

Solution dyeing requires enormous quantities of fibre to all be dyed the same colour. Not enough fibre to make 100 or 1000 garments, but in excess of 10,000 garments, all in the exact same colour. For many brands - ourselves included - this is not a reasonable quantity of fibre to purchase as they simply don’t sell sufficient products. But sometimes sales volumes are sufficient to enable solution dyeing, and one such example is in our purchasing of Gore-Tex Pro. We are one of the world’s leading Gore-Tex Pro brands and the backer on all of our Gore-Tex Pro garments is the same: it’s the same colour, the same fibre, and the same weave. As a result, our Gore-Tex Pro backers can be dope-dyed. It’s a small start, and with more coherent planning between all stages in a supply chain we hope to increase our ability to buy dope-dyed fabrics in future. Gore estimate a 47% reduction in environmental impact due to water use and a 2% reduction in CO2 output by switching to a dope-dyed backer. That’s a huge water saving and a useful CO2 saving.

Solution dyeing isn’t easy

The textile industry has been using traditional dyeing methods for years and has a good understanding of the various trials and tribulations in making even and consistent dyeing of fabrics. Dope dyeing isn’t all that new, but its relatively small influence means there is less widespread expertise in producing high quality dope-dyed fabrics. This, combined with machinery and industrial limitations limits its growth. For dye house owners it is a brave step to replace all their machinery and methods with new ones. That’s why it is important that we as both an industry and as consumers push for improvements to our dyeing methods and drive change. 

The inside of a dye house might seem a long way from the mountains, but the impact of textile dyeing, and indeed textile wet processing and finishing in general, can be felt around the globe. It’s an issue that’s easy to forget about because it’s a complex subject which can’t be neatly packaged for consumers. But aren’t the difficult and complex climbs the ones which matter the most? 

  

 

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