Nylon warp dyeing cloth dyed with acid dyes often appear inside and outside the problem of color , the use of high-temperature fabric of the predetermined shape (190 °C , 20 ~ 30 S) , the selected roll density 0 . 33 kg / m3, a set flow rate 220 m3 / h, added to the dyebath leveler M, with an organic acid-release control of pH and the like VS dyeing process optimization, can effectively control tricot dyed nylon layer is poor, the results are satisfactory dyeing.
Reel beam dyeing machine, also known dyeing machine, the dyeing autoclave, covered with a hollow shaft through apertures, sub-cylinder (barrel ingredients), a circulation pump, heat exchanger, high temperature high pressure dyeing machine by the other components of the truck axle. In the dyeing process , the fabric is wound on a perforated shaft, and the fabric roll is clamped by the iron frame to fix the two ends of the fabric roll . The high-Yang Cheng and large-flow professional pump is used to make the dyeing liquid positive (from the shaft). (inward) or in the reverse direction (from the outside of the cloth to the inside of the warp beam) to forcibly penetrate the fabric layer . Because the cloth is not stretched , it is very suitable for light and thin , easily creased nylon warp knitting cloth dyeing . The advantages of the high temperature and high pressure beam dyeing machine are that the fabric has good dimensional stability , is not easy to wrinkle , and has a flat cloth surface . However, warp dyed nylon warp knitted fabrics are prone to problems such as dyeing , layer difference , water ripple , poor reproducibility of dyeing , etc. I have resolved nylon warp knitted fabrics by optimizing the parameters of the cloth density , pump flow, and dyeing process. These quality issues are practiced and analyzed by khaki staining.
1 Dyeing process and optimization
1.1 Dyeing process line
Fabric: nylon warp knitted fabric (78% nylon + 22% lycra, l70 g/m2), width l60cm.
Dyes: Acidic NHF-S series (DyStar).
Auxiliaries: Organic acid VS (Huntsman textile dyeing), Acid levelling agent M (Clariant), Fixing N.
Dyeing process curve (slightly).
1.2 High temperature shape
The high-temperature preset shape can reduce or eliminate the tension unevenness produced in the spinning drafting and weaving processes of the nylon fiber, and provides a precondition for the uniform warping of the nylon warp knitted fabric to the warp beam. At the same time, it can avoid excessive shrinkage of nylon fiber fabrics, and even the occurrence of water leakage and curling on both ends . But the temperature is too high, resulting in loss of gray fabric predetermined elastic force, destruction of colored nylon performance, it should be reasonably controlled conditions according to a predetermined shape and specifications of the finished elastic fabric requirements. Select the predetermined temperature to l90 °C, time 20 ~ 30 S is appropriate.
1.3 Dyeing process optimization
Dye uptake refers to the process of dye transfer from the dye house to the fiber and to fiber transfection. First, the dye solution first enters the fiber's diffusion boundary layer. After the dye reaches the fiber in the diffusion boundary layer, the dye molecules are quickly removed. Adsorption on the fiber surface, dye molecules and the fiber surface hydrogen bonding , van der Waals force or Coulomb attraction , the dye adsorption on the fiber surface , the formation of a dye concentration in the fiber inside and outside the difference , and thus spread to the fiber inside and fixed in the fiber, dyeing process It is the result of a large number of molecular movements.
Nylon fabric dyed with acid dyes during the dyeing process is too fast, easy to dye , a serious layer. Especially sensitive colors such as khaki are the most difficult to control. In this experiment, as an evaluation index Khaki, one-way outflow of the selected dyeing method.
1.3.1 Effect of Rolling Density on Chromatic Aberration of Inner and Outer Layers and Its Optimization
When warp beam dyeing, the density of the fabric is too small, the fabric is easy to slip, the outer layer of dyeing liquid leaks when dyeing, and the left and right color difference and dyeing occur in the outer layer; the overwound density of the fabric is too large, resulting in uneven dye penetration the difference between the inner and outer color layer is increased, and the actual production prone wave pattern.
Coiling density is too low, the inner and outer fabric layers chromatic aberration is increased; cloth increased density, is not conducive to the diffusion of dye molecules, the outer layer is dyed. The optimum winding density is 0.33kg/m3.
1.3.2 Influence of traffic on the color difference between inner and outer layers and its optimization
Due to the uniaxial outflow of this test beam dyeing machine, it is determined that the dye molecules are first adsorbed on the surface of the inner layer fabric. The amount of adsorption of the dye molecules in the inner layer of the warp beam per unit time is greater than that of the dye molecules in the outer layer of the beam. The size of the dye directly affects the penetration of the dye liquor. Dyeing flow rate (ie, pump power) is too small, the dye solution cannot penetrate the fabric on the warp beam, and large dyeing or gradual coloration occurs on the cloth surface; increasing the dyeing flow (ie increasing the pumping power) can be achieved to a certain degree. this reduction in the difference, to speed up the movement of dye molecules, facilitate the diffusion of dye molecules, so as to achieve the effect of narrowing the inner and outer color layer; however, the main pumping power is too large, wasteful power resources first, followed after when dyeing liquid ejection port, due to the injection pressure will cause large channeling cloth. Therefore, when the main pump is selected, the above phenomenon must be taken into consideration, the efficiency of the main pump is referred to the highest, and the energy consumption is minimized.
The dyeing flow increases , and the color difference between the inner and outer layers decreases . However, if the flow rate is too large , it will cause energy waste and be easy to pick and shift . The optimum dyeing flow rate is 240 m3/h.
1.3.3 Dyeing temperature optimization
Dyeing temperature rise may be increased dye molecules in the dye bath and the kinetic energy of the fibers, to reduce agglomeration of dye molecules in dye bath, while fibers causes expansion, favor dye molecules into the interior of the fiber, permeable to achieve uniform dyeing.
As the dyeing temperature rises, the dye uptake rate increases, and the dye uptake rate is approximately balanced above 95°C. Thus determined dyeing temperature was 95 deg.] C; the same time, slow heating rate likewise be dyed slowing the rate of dyeing acid dyes on nylon.
1.3.4 Levelling agent application
The affinity between acid dyes and nylon fibers is high, and the dye uptake rate is also high, but the dyes lack mobility on the fibers. When the warp beam is unidirectionally out - flow dyed, the dyeing liquid is filtered through the fabric layers , and the outer layer is more in pressure difference. small, the less the relative amount of dye, flowers and easily lead to color difference layer, which is more apparent when the color sensitive dyed khaki and the like. Suitable leveling agent selected to reduce the amount of force between dyestuff and fibers, reducing the rate of dyeing dye increased mobility on the fibers a dye, the main means of overcoming these flaws. Our practice has shown that the khaki color leveling agent M is suitable for 2 g/L.
1.3.5 Effect of pH
The pH value is an important parameter of the acid-dyed nylon fiber. The pH value of the bath affects the dyeing rate and the dyeing rate. The dyeing process is related to the reproducibility of dyeing at each stage. Neutral dye, the zwitterionic structure nylon (+ H3 N-PA-C00- ) exists, carboxyl protonated ions under acidic conditions, all of the amino group present in the form of -NH3 + ions at the isoelectric point, but only a carboxyl group in part -C00 - present in the form of ions. When the isoelectric point of the dye, the dye ionically mainly fixed on the end group fibers, nylon fibers in an acidic medium can be formed in -NH3 +. The stronger the acidity is, the lower the pH is, and the more -NH3+ is formed, the faster and more the dyeing of the anionic acid dye is, and it is easy to produce too fast and dye the flowers.
Isoelectric pH value of about 6 nylon fiber or the like, to select the beginning of dye dye bath a pH of 6 to 7.5, can be improved levelness and stability differential cylinder, releasing an organic acid selected VS with increasing temperature gradually release Acid, which slowly slides the pH of the dye solution from neutral to acid, slows down the rate of nylon dyeing on acid dyes , and effectively avoids dyeing unevenness and dye uptake at all stages of stable dyeing. First dye strict control of pH and the dye bath during dyeing to move gradually slide acidic, the pH may be controlled entirely within a small error range. The actual production proven: Comparison with the organic dye releasing acetic acid VS conventional, better performance level difference.
2 Optimize the process to produce dyeing results
Trace the finished product dyeing effect using the optimized process for large production .
2.1 Left and right color difference performance
Datacolor color measuring system with nylon tricot finished beam dyeing color large-scale production is measured, the data show that large-scale production of the outer layer of the finished product, the middle, left, right inner template is less than the color difference â–³ E O.Model And Model Mixed Fabric
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