Polyester dyeing should not take longer than 150 minutes – but few people know
Polyester accounts for more than 50% of the global textile fibre market – no matter the end use. That’s a lot of polyester needing to be pre-washed, dyed and finished, packed and distributed to customers all around the world. This puts pressure on dyehouses, that need to deliver high quality products while speeding up their processes. But quality takes time. For example, dyeing polyester takes up to 200 minutes including reduction clearing. In these 3+ hours, a lot of energy and valuable process time goes to waste and machines can’t be used for other batches, holding back dyehouse performance. It’s time to put on our innovation hats and find out which opportunities there are to solve this problem. In this blog, we’ll get you up to speed- literally.
The two faces of polyester
Polyester is on the rise. It’s the most commonly used material in textile products, either in pure form or as part of a blend. Luckily, there’s enough polyester to serve the growing world population (because unlike cellulosic fibres, we can make it ourselves), but that’s not the issue here. Customers, both brands and end-users, require textile products to be delivered as fast as possible, but they also want them to be produced sustainably. Then there’s the influence of governments, setting up incentives to motivate dyehouses to make their production processes more sustainable. This focus on sustainable textiles is good news to our planet and our (future) offspring; however today, it puts even more pressure on dyehouses. As a dyehouse manager, you need to get to high quality faster while saving out on energy, valuable process time and water. There are several ways to do this, but the most effective way is probably to reduce polyester dyeing time. When done right, this measure can reduce energy usage by 30%. That’s good news!
The eternal fight against time
The not-so-good news is that the dyeing process of polyester depends on so many variables that it’s impossible to create a one-size-fits-all recipe to speed up dyeing time. Machine type, water quality, dyestuff, auxiliaries, dyeing method, end-use: they all have an impact. Then there’s the influence of the polyester type itself, and the many blends it’s used in. You’ll understand that 100% polyester responds to dyeing processes differently compared to a blend of polyester and, let’s say, cotton. This is why many dyehouse managers and technical engineers came up with rules of thumb to make sure absolutely nothing goes wrong, no matter the variables. Very understandable, but it did result in a rather long dyeing time of around 200 – 220 minutes. First, machines are pre-heated to 40 degrees, where after the polyester product is added and temperature rises one degree per minute. Then, the polyester stays in the machine for another 40-50 minutes. All this time, the clock keeps ticking.
It’s safe to say that, in order to speed up polyester dyeing time, we need to let go of rules of thumb. “Instead, focus on your specific situation,” says Harald Gruenewald, business development manager of Classical Textiles at Tanatex. “Which machines and dyestuff do you use? What type of auxiliaries do you add? Do you work with blends or with 100% polyester?” The answers to these questions help you find the perfect balance between speed and quality, which is different for every dyehouse. “To get to this balance, you can’t go around the lab,” explains Harald. “Here, lab technicians measure how much time you can save in which phase of the dyeing process.” The first part of the heating process, for example, is a relatively safe part as colours will only start to migrate to the fabric around 90 degrees. At 130 degrees, colour migration is in full swing, meaning you need to slow down just a little bit to get to evenly spread colours.
“Twenty minutes doesn’t sound like a lot- but it is!”
“If you know exactly how much time you can save out per dyeing cycle and you try it out in real life, you’ll soon realise that lab research pays off,” says Harald. “Let’s say you find out that you can save twenty or thirty minutes per dyed batch, and you do six batches per day on one dyeing machine. This means you’ll save 120 to 180 minutes per day on one machine, which is between 14 – 21 hours per week and around 56 – 84 hours a month. Think about it: 84 hours less energy and water usage! Not to mention the increase of capacity that this time reduction brings you. “So, go to the lab and find out how many minutes you can save per cycle,” says Harald. “You’ll be surprised what twenty minutes can do for your business and carbon footprint.”
Do you want to learn more about dyeing done perfectly? Then we may have something for you. In the white paper below, you’ll read all about ways to speed up dyeing time while improving quality. Sounds too good to be true? Download the document for free and see for yourself!