Su Hua, Li Huamei, Qi Jin (Taixing Jinji Dye Co., Ltd., Taixing, Jiangsu 225404, China)
Abstract: Reactive Turquoise KN-G is prone to color point, pigmentation and color flowering during dyeing and darkening. Appropriate and appropriate leveling agent is added during commercial dyeing processing, and scientific dyeing can be used to avoid the above problems and improve the color fastness.
Key words: reactive dyes; dyeing; leveling agent; retarding active cuilan dyes with copper phthalocyanine structure as precursors, bright color, low cost, good dyeing performance, unique for color matching with other color reactive dyes The status is widely used in cellulose fiber dyeing. However, due to its molecular structure, the molecular structure is circular, the molecular weight is large, the directness is high, the diffusibility is poor, and it is difficult to penetrate into the interior of the cellulose fiber, which is easy to cause uneven dyeing; in particular, dye agglomeration occurs after the addition of soda ash, and color points are easily generated. Color spots, color flower phenomenon, more floating colors, poor color fastness and other issues [1 ~ 2]. By adding a leveling agent, sodium sulfate and an alkali agent can be correctly used in the dyeing process, and a suitable chelating dispersing agent, soaping agent, fixing agent, etc. can be selected to solve the problem of color point, color spot and color flowering during dyeing. Improve the color fastness.
1 Â·Test part 1. 1 Test reagent and dyeing material active Cuilan KN-G, Taixing Jinji Dye Co., Ltd.; Sodium sulfate, soda ash, all industrial products; Leveling agent JY-21, Jiangyin Auxiliary Chemical Co., Ltd. .
1. 2 test instrument translational room temperature dyeing machine, Jingjiang Dyeing Machine Manufacturing Co., Ltd.; ALC-110. 4 electronic balance, Shanghai Ruisai Scientific Instrument Co., Ltd.; SF600 color measuring instrument, Datacolor Company of the United States; Y572B friction fastness meter, Changzhou Second Textile Machinery Factory.
1. 3 Test 1. 3. 1 Alkali-resistant salt stability test Take the active Cuilan KN-G at a concentration of 10g / L, and add the calculated amount of leveling agent JY-21 (0, 0.5, 1 respectively 0, 1. 5, 2. 0g / L). Prepare the active Cuilan KN-G solution, add 60g / L sodium sulfate and 20 g / L soda ash at 50 Â° C with stirring. Immediately after the addition, use the glass rod to draw the above solution and slowly infiltrate the filter paper to see it. There is no obvious coagulation of the dye in the center of the filter paper.
1. 3. 2 dyeing leveling test performance of leveling agent Commonly used test content: leveling experiment, dyeing rate experiment, the influence of dyeing time on dye uptake rate, the effect of fixing temperature on dyeing intensity and shade Wait.
Take 2% (by fabric quality) of active Cuilan KN-G and different amounts of leveling agent (0, 0.5, 1.0, 1.5, 2. 0g / L, respectively) and 60g / L The sodium sulfate was added to the dyeing tank at a bath ratio of 1:20, and the cloth sample was placed therein and shaken. The dyeing tank was placed in a translational dyeing machine, and the temperature was slowly raised from normal temperature to 60 Â° C, and the color was absorbed at 60 Â° C for 30 min. Then, a quantitative amount of 20 g / L soda ash was added to the temperature to 80 Â° C, and the color was fixed for 60 min. The swatches were washed several times with 50 Â° C water, neutralized with acetic acid for 10 min, then boiled with 2 g / L soap at 95 Â° C for 15 min, rinsed 3 times with 50 Â° C water, and rinsed with cold water for 10 min. Dry the washed cloth sample and measure the K/S value (K is the color material absorption coefficient, S is the color material scattering coefficient) or convert the intensity by the SF600 colorimeter, according to the dyeing condition, K/S value or Strength and various properties to determine the levelness of dyeing.
(1) The effect of different levels of leveling agent on the dyeing condition is expressed by K/S value and tested by SF600 colorimeter.
(2) Using the leveling agent JY-21 dosage of 1.5 g / L as an example, the effect of dyeing time on the dyeing results was tested at 80 Â° C, expressed as K/S value, see Table 1.
(3) According to the above dyeing conditions, the amount of the leveling agent is 0. 5, 1. 0, 1. 5, 2. 0g / L according to the dyeing conditions of the above-mentioned dyeing agent JY-21 Dyeing, measuring the color, intensity and various fastness of the product, see Table 2.
(4) The amount of the leveling agent is 1. 5g / L, according to the above dyeing process formula, but the fixing temperature is 60 Â° C, 80 Â° C conditions, the product dyeing strength and various fastness, see Table 3.
2. Results and discussion 2. 1 Principle of the test The molecular structure of the active Cuilan KN-G dye is ring-shaped and relatively large, the water solubility is poor, and the diffusion performance is poor. The solubility in the dye solution at 60 Â° C is good. However, under the condition of fixation, with the addition of soda ash, the degree of aggregation of the dye increases sharply, and salting out and coagulation occurs, resulting in a decrease in the water solubility of the dye. At the initial stage of dyeing, the dyeing rate is fast, resulting in uneven color, color point and color flower. Therefore, in order to solve these problems, it is first necessary to improve the diffusion performance of the dye in the fiber and control the dyeing rate at the initial stage of dyeing. The leveling agent is added to the dyeing to dissolve, disperse and delay dyeing. Especially when a large amount of electrolyte is present in the dyebath, the dye molecules remain stable and do not cause salting out aggregation, thereby obtaining a good leveling effect and a high color fastness.
2. 2 Stability of alkali-resistant salt The speckle method was used to test the presence or absence of obvious agglomeration of dye on the filter paper. The test results of alkali-resistant salt stability are shown in Table 4.
It can be seen from Table 4 that the dye is precipitated after adding sodium sulfate and soda ash for 8 minutes without adding the leveling agent JY-21. The solubility of active Cuilan KN-G can reach 150g / L at 50 Â°C water temperature, mainly because the dissolution of active Cuilan KN-G mainly depends on the soluble sulfonic acid group in the dye molecule and the ester of Î²-ethylsulfone sulfate. The solubility of the Î²-ethylsulfone sulfate group is higher than that of the sulfonic acid group. The solubility of the active turquoise is determined by the ionization degree of the sodium ion on the soluble group. The higher the ionization degree, the higher the solubility. it is good. When sodium sulfate is added, the sodium ion in sodium sulfate inhibits the ionization of the dye. The attraction between the dye molecules is greater than the repulsive force between the molecules. The sodium sulfate exceeds 60g / L, the electrolyte in the dye solution is excessive, and the ionization balance is broken. The active turquoise will change from the dissolved state to the non-dissolved state, causing salting out phenomenon, and the dye will agglomerate, but the dye will not precipitate in about 1h; however, the hydrolysis of ethylsulfone sulfate in the dye is enhanced after the addition of soda ash, water soluble The large ethyl sulfone sulfate is hydrolyzed to a vinyl sulfone group, causing a rapid decrease in the solubility of the dye. In addition, the presence of sodium sulfate causes the dye to be salted out and agglomerates, resulting in the precipitation of the dye. Therefore, after the soda ash is added during the fixing process, the dye is easily precipitated due to the absence of the leveling agent, and the precipitated dye adheres to the surface of the fiber, and does not react well with the hydroxyl group on the cellulose fiber to form a stable covalent bond. When the dyeing is finished, the dye is peeled off from the surface of the fiber when it is washed and soaped, resulting in color spots, stains and tinge on the surface of the fiber, resulting in uneven dyeing.
It can be seen from Table 4 that the dyeing time of the dye solution with different amounts of leveling agent JY-21 is extended from 10 min to a maximum of 2 h. According to the requirements of the market and dyeing applications, the amount of leveling agent is controlled to 15% to 20%, and the commercial dye is stirred under the conditions of sodium sulfate 60g / L and soda ash 20g / L for more than 1h, and the aqueous solution is free from dye precipitation. The method can be tested before sampling before dyeing, and then subjected to dyeing leveling test and magnifying sample, which can reduce the loss of large production.
2. 3 Leveling of dyeing 2.3.1 Effect of the amount of leveling agent on the dyeing condition The effect of different leveling leveling agent on the dyeing condition is represented by K/S value, tested by SF600 colorimeter. The test results are shown in Table 5.
It can be seen from Table 5 that as the mass concentration of the leveling agent increases, the color depth of the surface of the fabric (the K/S value becomes smaller) gradually becomes shallower, indicating that the mass concentration of the leveling agent in the dyeing system increases, and the dyeing is slow. The effect becomes more and more obvious, which is beneficial to uniformly dyeing the dye onto the fabric, and reducing or avoiding the occurrence of color spots, color spots and smudges.
2. 3. 2 Effect of dyeing time on dyeing condition According to Table 1, the effect of dyeing time on the dyeing condition: K/S is not much different when the dyeing agent is added for initial dyeing, indicating that the dyeing agent changes slowly after adding the leveling agent. The K/S value of the leveling agent does not change rapidly, indicating that the sample without the leveling agent is dyed at a high speed, and it is easy to produce color points, spots, and flowers. After the leveling agent is added, the dyeing speed becomes slower. It is good for solving the problem of color flower and color point.
2. 3. 3 The effect of leveling agent on the intensity and fastness of dyeing color light According to the data in Table 2, it can be seen that the color change of the dye after adding the leveling agent is not large, and the leveling agent is added with a little darker color; The strength decreases slightly with increasing level of leveling agent. Adding dyeing agent has improved soaping and rubbing fastness: The color fastness of soaping is increased by half grade, the color fastness of soaping is improved by 1 to 2 grade; the dry rubbing fastness is improved by half grade, wet rubbing fastness Increase the level of 1 to 2. This is mainly because the dyeing liquid in the fixing stage changes from neutral to alkaline, the dye will be colored instantaneously, the adsorption balance is broken, and the dye in the dyeing solution will quickly react covalently with the fiber, resulting in uneven coloration and poor dye permeability. The compound with heavy color, soaping and rubbing does not form a covalently healthy compound, which easily falls off from the surface of the fiber, resulting in poor color fastness. After adding the leveling agent, the above disadvantages are basically overcome, and the fastness performance is improved.
2. 3. 4 The effect of fixing temperature on dyeing strength and fastness According to the data in Table 3, it can be seen that: using leveling agent to fix color at 80 Â° C and 60 Â° C, the color light is basically unchanged, but 80 Â° C solid The color strength is increased by 14%, and other soaping fastness and rubbing fastness are also improved by one level. The general KN type reactive dye has a fixing temperature of 60 Â° C, but the active Cuilan KN-G has a special structure, a large molecular weight, high directness, poor diffusibility, and difficulty in penetrating into the fiber, resulting in uneven dyeing. In order to overcome the above disadvantages, the diffusion of the molecule can be increased by increasing the fixing temperature, and at the same time, the cellulose is sufficiently expanded, so that the dye can chemically react with the hydroxyl group on the cellulose molecule to form a covalent bond, and the dye thus formed - The covalent price of cellulose is relatively strong, and the dyeing strength, soaping fastness and rubbing fastness are correspondingly improved.
According to the above experimental situation, it can be seen that the addition of the leveling agent can solubilize, disperse and retard the dye, so that the dye can reduce the hydrolysis of the dye even in the high electrolyte and high pH. Coagulation, the color absorption rate tends to be gentle, the dye color is slow, especially in the fixing stage, the dyeing effect is better, so that the color point, the color spot and the color flower phenomenon can be overcome and reduced.
The level of leveling agent is large, the effect will be better, but the excessive amount will cause the dyeing strength to decrease, and the color light will also change, resulting in dark shade. According to the change of dyeing intensity and leveling effect, the time of alkali salt stability is small, the effect is not obvious; the dosage is large, the dyeing intensity will be greatly reduced, and the color light is not guaranteed. The amount of the leveling agent is preferably controlled at 1.5 to 2 g / L. The leveling effect is good, the dyeing strength can be ensured, the color light changes little, and the floating color dye on the cellulose surface is relatively small, so that the soaping fastness and the rubbing fastness are improved.
3 Â·Conclusion The appropriate amount of active leveling agent JY-21 can be added to the active Cuilan KN-G to improve the solubility, alkali resistance and dispersion of the dye. Especially in the fixing stage, the effect is more obvious and the retarding effect is good. The soaping fastness and rubbing fastness of the dye can be greatly improved. The level of leveling agent should be kept at about 1.5 ~ 2g / L. The cotton fiber pretreatment should be cleaned, the correct material should be prepared during the dyeing process, the amount of sodium sulfate should be 60g / L, and then added at 80 Â° C with 20g / L soda ash. Fixing, after washing, it should be fully washed and soaped, and the temperature and acidity and alkalinity should be controlled after finishing. Only in this way can the dyeing quality be ensured, and the production of color spots, stains and color flowers can be eliminated, and the leveling effect can be achieved.
References  Chen Xuan. Production Practice of Reactive Blue-KN-G Dyeing of Cotton Knitted Fabrics[J]. Dyeing and Printing, 2001, 36( 3) : 26-27.
ç¼ªæ¯“é•‡. Dyeing Characteristics and Dyeing Process of Reactive Turquoise Blue G[J]. Dyeing and Printing, 2005, 31( 2O) : 10-14.
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