Application of Defoaming Agent in Dyeing and Finishing Production
During the production and processing of knitted fabric printing and dyeing, foaming causes the fabric to float on the water surface, and in severe cases, cloth blocking occurs (overflow jet dyeing machine). At this time, people often hope to use low-foaming surfactants to meet the needs of various fast and efficient processes, so defoamers become the preferred auxiliary agents for technicians.
Defoamers use organic compounds such as alcohols, ethers, and silicone oils to immerse surfactant foam and extend in all directions, making the foam thinner and destroying the directional molecular adsorption layer formed on the gas-liquid surface until the foam breaks. In the past, many printing and dyeing companies did not understand the dosage and performance of defoamers when using defoamers during operation, so they found that the surface of the fabric was stained with irregular oily substances when the grey fabric came out of the cylinder after only a few cylinders. When encountering this phenomenon for the first time, it is unclear where so many oily substances come from, because this oily substance is very bright on the surface of the fabric, and it penetrates into the fabric when touched by hand, and there are traces of stains when it is taken out, and it cannot be removed cleanly. After searching for the cause from many aspects, it was analyzed that the oil was caused by the demulsification of the defoamer. Once the fabric is stained by this dirt, it is difficult to remove it. After many experiments, it is known that the greater the amount of defoamer used, the more serious this phenomenon is. It is more obvious on chemical fiber fabrics such as polyester-cotton and pure polyester (while this phenomenon does not occur on machines without defoamers). Combined with the scum and dirt produced by metal ions or impurities in fibers, auxiliaries, and dyes, irregular color spots, color blocks, and oil stains adhere to the fabric. Therefore, while eliminating foam, it also brings many unfavorable factors and negative effects, and even causes economic losses.
