EDE, Netherlands — January 3, 2020 — Polyester accounts for more than 50 percent of the global textile fiber market — no matter the end use. That’s a lot of polyester needing to be prewashed, dyed and finished, packed and distributed to customers all around the world. The dyehouse manager might confirm that pressure is on to deliver high quality products while speeding up their processes. Generally, dyeing polyester takes up to 200 minutes including reduction clearing. Can you speed up, and still reach high quality while saving out on energy, valuable process time and water? Tanatex Chemicals sees opportunities to do this in several ways, but the most effective way is probably to reduce polyester dyeing time. When done right, this measure can reduce energy usage by 30 percent.
The eternal fight against time
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-percent polyester responds to dyeing processes differently compared to a blend of polyester or 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. It resulted in a dyeing time of around 200-220 minutes. First, machines are preheated 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.
Stop relying on rules of thumb
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,” said Harald Gruenewald, business development manager of Classical Textiles at TANATEX Chemicals. “Which machines and dyestuff do you use? What type of auxiliaries do you add? Do you work with blends or with 100-percent polyester?” The answers to these questions help to 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,” Gruenewald explained. “Our 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 colors start to migrate to the fabric around 90 degrees. At 130 degrees, color migration is in full swing, meaning you need to slow down just a little bit to get to evenly spread colors.
“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 realize that lab research pays off,” Gruenewald said. “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 and 21 hours per week and around 56 to 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,” Gruenewald said. “You’ll be surprised what twenty minutes can do for your business and carbon footprint.”
Posted February 19, 2020
Source: TANATEX Chemicals