The traditional dyeing method for acrylic fiber is to dye the finished silk or fabric using conventional rolling dyeing and high-temperature steaming methods. This dyeing method is expensive and difficult to treat wastewater
Big. As a new environmental protection dyeing technology, gel dyeing technology is simpler than traditional dyeing technology, with lower dyeing cost, energy saving and simple production sewage treatment.
Technological principle of gel dyeing process gel dyeing fiber refers to dyeing of wet spinning fiber before structure densification.
The fiber without drying and densification has low orientation of macromolecules, which makes the fiber structure very loose. The fiber is still in the initial swelling state. The fiber structure is similar to the expanded gel with minimal intermolecular bonding. There are a lot of micropores in the fiber. At this time, the measured specific surface area of the fiber is 100~200 times of the specific surface area of the fiber after drying and densification. At this point, the fiber theoretically has a super high dye uptake rate.
In the process of gel dyeing, the porosity of the unstructured densified fiber and the particularity of the maximum specific surface area resulting from it can make enough dyes penetrate into the core layer of the fiber. The process of gel dyeing is that the positively charged cationic dye chromophore combines with the negatively charged sulfonic acid radical group on the dyeing site of the rubber filament and remains inside the fiber micropores. When dried and densified, the micropores of the fibers close, allowing the color to physically solidify and remain on the fibers, thereby greatly improving the color fastness of the finished fibers to meet the high specification requirements of enterprises for fibers.
The process can choose to dye at the position before hot stretching after washing or before drying and densification after hot stretching. After washing and before hot stretching, perform gel dyeing, and the linear speed of the tow is 30~40m/min. Under the premise of the same dye concentration and dye time, the configuration of the dye bath can be relatively smaller to reduce equipment investment.
When the wire speed of the filament bundle reaches 200m/min or above after hot stretching, the fiber has already been stretched six times, and the diameter of the single fiber becomes thinner, making it easier for the dye to penetrate into the core layer. However, at such high operating speeds, meeting the dye loading conditions requires relatively high costs in terms of dyeing equipment configuration, as well as a large production land area. The current gel dyeing process mostly adopts gel dyeing treatment after washing and before hot drawing, which can also achieve satisfactory results.
Its advantage is that the traveling speed of the fiber bundle before hot drawing is 5-7 times slower than that after hot drawing. At this time, bath dyeing is used. Under the condition of constant dyeing time, the length of the dyeing bath can be relatively shorter, which saves space and reduces equipment investment. The pilot plant of Daqing Petrochemical Company's acrylic fiber plant adopts the water washing dyeing process.
Experimental conditions equipment and dyeing system gel dyeing fiber research the energy of the test wave will change with the change of angle, and the energy will reach the maximum in the direction perpendicular to the emission plane.
An environment-friendly dyeing technology of acrylic fiber, namely acrylic gel fiber dyeing technology, is introduced and analyzed.
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