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Growing Trends of Knitted Fabric Dyeing and Finishing Process

Growing Trends of Knitted Fabric Dyeing and Finishing Process

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China has been joining WT0 for six years, and the textile quota has been cancelled, the main obstacle of the current export of textile clothing is technical barriers such as green and environmental protection. In order to strengthen the protection of human health and environment and reduce the harm of chemicals, the European Union has introduced the REACH regulation, which makes the world textile trade competition fiercer. Our knitting dyeing and finishing industry will be unable to continue if it is to stay in the low labor cost advantage and price advantage, to accelerate the improvement level of science and technology is urgent, we should relying on technology, research on new technology, to improve product technical content and added value continuously through innovation, enhancing the grade of the product and its competitiveness in the international market.

Cleaning production is the principle of dyeing and finishing process design
The state environmental protection administration made it clear that by 2010, all printing and dyeing enterprises in China should adopt environment-friendly raw materials and implement cleaner production. The process of knitting dyeing and finishing must meet the requirements of cleaner production, and make clean production the principle of the design of dyeing and finishing technology is the inevitable trend of dyeing and finishing process. Knitting dyeing and finishing enterprise should pass the certification of the IS014000 and establish the guarantee system of enterprises environmental protection, to improve environmental control ability of the product quality, create conditions to apply for the "environmental protection and ecological" label of Oek0-Tex standard series, in order to increase consumers' trust of our products and competitiveness in the international market, bring long-term benefits for the enterprises.

To conduct clean production of dyeing and finishing process design, should improve the utilization rate of resources at first, reduce the generation of pollutants and emissions, water saving, energy saving, use less or no toxic dyes, auxiliaries and use less waste or no waste technology. To achieve energy conservation, emission reduction and choose to use efficient equipment and perfect management system from the source of the process design, therefore to produce environmental friendly a knitting products.

Knitting dyeing and finishing technology should grow in the direction of one-off success
Modern control technology based with computers has been widely used in knitting dyeing and finishing apparatus, equipment, production and management, from the laboratory, computer color matching, the dyeing machine computer process control, etc.
In order to reduce the time of delivery, dyeing and finishing process design of small batch and multi-variety should be one-off success in order to reduce the cost and enhance the competitiveness of the product. The process test of the laboratory must be refined, all the technological parameters, the accuracy and reproducibility of small sample tests should be measured. An accurate process can be achieved after small, medium and large sample test, a one-off success can be achieved according to process production.


Pretreatment technology process grows to short process, high speed, high efficiency and clean production direction

(1) Application of enzyme
Using pectin, hydrogen peroxide to remove enzymes and cellulase in the pretreatment process, reduce water consumption, save energy, and reduce the burden of waste water treatment.

(2) High temperature speed drift
As mentioned before, non-caustic rapid oxygen bleaching process is a kind of clean production process. This process use rapid oxygen bleaching agent and hydrogen peroxide only, keep warm at ll0 ℃ in high temperature overflow machine about l5 ~ 20 mins.

When the dosage of oxygen bleaching agent is 2.5~3 g/L, PH value can stabilize at 10.5 ~ 10, make H202 linear decomposition by the increase of temperature and the extension of time, the decomposition rate can thus reach more than 85%. Rapid oxygen bleaching agent have function as scouring, emulsification, degreasing, integrate detergent washing, adjust pH value, etc. it can replace caustic soda, penetrating agent, stabilizer, degreaser and several other auxiliaries fundamentally in oxygen bleaching process. Compared with caustic soda process, this process has less fiber weightlessness, the fabric is soft (can reduce 1/3-1/2 softener dosage) and easy to clean after bleaching, just wash once with warm water is enough, the sewage of bleached water has a PH value less than 9, COD value is half less than caustic soda process, which is easy for wastewater treatment and has a good reproducibility.

(3) Continuously evaporating knitted fabric
Continuous oxygen bleaching based on cylinder open width and slitting open width, compared with overflow machine oxygen bleaching, the bleaching quality has been greatly improved, cloth is bright and clean, no sanding, no fine wrinkles, water consumption is 1:10, per ton fabric's water consumption is 1-0. 8, it has high production efficiency. Continuous pretreatment of slitting open width can matching the open-width mercerizing, open-width tie-dye, open-width reactive dyes printing, to realize the high grade knitting fabric production line.

The mercerizing process of the open width knitted fabric
High quality knitted fabrics such as high - level yarn products, usually need to go through the mercerization. Some domestic bleaching and dyeing house with strong economic strength should develop open-width knitted fabric mercerizing, the color of knitted fabric processed by open-width mercerizing dyeing is gorgeous, cloth cover is luster, with more size stability and low shrinkage, it can save 30%-40% dyes and can matching open width scouring and bleaching, open-width dyeing, open-width printing, the process route is more reasonable.

Airflow dyeing technology promotion
Airflow dyeing machine is using the principle of aerodynamics, using pressure air to optimize the dyeing effect of overflow dyeing machine, this can make the dyed cotton's bath ratio to l: 4, compared with the conventional dyeing, reduce about 50% water consumption.Due to the small bath ratio, it can reduce the dosage of 10% or l5 % dye material, reduce 30% steam consumption; Besides, the fabric has low tension, this reduces creases, uneven dye and improves the fabric's hand feeling at the same time.

The dyeing quality can be improved by airflow dyeing technology, a one-off successful dyeing is achievable. The technology of airflow dyeing has been continuously improved. For example, intelligent injection system is adopted to simplify dyeing procedures and significantly reduced the dyeing time. The whole function vertical equipment cylinder is set up, the cleaning water can be programmed according to the requirement, and the automatic cleaning filtration system is configured. The storage tank is changed into variable load storage tank, and each tube can be completely independently controlled, which is worth spreading.

Open width knitted fabric cold pad-batch dyeing process
Knitted fabric open-width cold pad-batch dyeing process technology is advancing day after day, it adapt to the small batch with many varieties’ production and does not need to add salt, saving dyes, auxiliaries, water, steam, less energy consumption, reducing the drawbacks, such as fabric wrinkle, grinding, etc.

After open-width pretreatment of cellulose fiber fabric, firstly, padding the reactive dyes by uniform padder, and send it to the stacking system by feed preparation unit roller, coiling with constant tension in the whole piling project, so as to avoid any squeeze on the knitted fabric, after fabric rolled up to a predetermined time, then wash it in the drum type open width washing machine.

The open width cold pile dyeing equipment is equipped with the optimized anti-rolling edge device. Open width processed knitted fabric does not bring any wrinkle on the fabric. Dyes and auxiliaries are added in different proportions, and the amount of liquid can be reproduced to maintain the dynamic balance and high accuracy. Using a PLC error compensation roller to adjust the rolling pressure effect, make the process control be datamation, bring down the fabric tension. Special temperature control system can measure the temperature online to guarantee the constant reproducing temperature. In this way, the dyeing process parameters can be controlled to ensure the one-off dyeing success. At present, there is only one factory in Guangdong province that has introduced the open width knitting fabric dyeing equipment and has put it into production.

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