Learning Points│How to control the process of dyeing and finishing of colored fabrics

Twilight fabrics are unique in style and have high added value. Due to the long production process and complicated process, in practice, inaccurate or inconsiderate changes in the color of the subsequent process may result in deviation of the finished product from the specified color, or even remedy. The difference between dyed fabrics and dyeing fabrics in dyeing and dyeing industry is not color yarns. The fundamental difference between yarn dyeing and white weaving is that the former dyes and then weaves, while the latter dyes the fabric first. The change of light color after dyeing is very complicated. It has a great relationship with fabric structure, weaving machine technology and finishing technology and color matching pattern. For example, the relationship between colored light and fabric structure, the density and weft density is not the same as the original, shade is not the same, especially in the latitude and longitude color shade difference is greater; weaving machine technology has a great impact on the color, the most obvious The difference is between the sample and the large sample, because the sample has small longitudinal tension and large weft tension, while the large production machine has large warp tension and small weft tension; in addition, it is also related to the position line. There is a difference in the color of the same species that is woven from the back beam and a low back beam. For the finishing process, the mercerization of mercerized and non-mercerized light differs greatly. Generally, after the mercerizing, the shade is darker and redder. The higher the setting temperature is, the higher the setting temperature is, the more reddish and darker the colored light is; The relationship with the color matching pattern, for example, if the customer requests to change the fabric texture or the warp and weft density, it can't control the original yarn color shade, if necessary, it needs to make a pioneer sample and adjust the color light. Therefore, for the understanding of colored light, we must understand the fabric structure design, weaving machine technology, finishing and color molding, etc., can not only stay in the dyeing yarn alignment color.

Yarn dyeing is the first process in yarn-dyed production. It is an important link and modern management should be adopted. First of all, from the proofing process, the current status quo of general management is to receive a sample, first assigned to the proofing workers to proof, and then confirm the prescription of the proofing workers together with the master of yarn processing. This traditional model can no longer adapt to modern management systems. The correct method should be to group together all the process recipes that have been staked out several times (that is, to have a successful one). Divide them into different series according to different colors (such as red, yellow and blue) and different dye production units. Each series is subdivided into serial numbers. These prescriptions are stored on a computer and searched by the code number of the dyed yarn. A variety of colors can be found. At the same time, all yarn samples of these prescriptions are sampled and chromatographed. The advantages of using this management method are:

(1) Passing a lot of times to pass a successful prescription is a more successful prescription, especially its compatibility, physical indicators and operability are more suitable for production.

(2) From the management point of view, using a computer to deal with, more convenient and centralized management.

(3) Save labor and improve efficiency. Between the sample cloth and the other cloth sample, many colors between one color and another color are similar, they may be similar colors or sister colors, but they are distributed to a number of people for proofing, wasting time and labor, and affecting One success rate for lofting.

(4) It is possible to classify various dyes into deep, medium and light colors according to the use of materials. This will not only strengthen the assessment of internal accounting for economic accounting, but also provide certain reference materials for future external processing.

(5) Supervision and control can be strengthened. For example, the assessment of a success rate, the consumption of dyes and other assessments.

2.1 Additives

In order to reduce the errors in proofing and in-cylinder dyeing, it is required to be consistent with dyeing in the dyeing process during the proofing process, that is, it is required to add auxiliaries that are consistent with the large goods in the dyeing bath. Additives and their usage are as follows:

Glacial acetic acid 1g/L

(ie 1g/L to 100mL draw 5mL)

Diffusion agent NND1.5g/L

Levelling agent 10111.5g/L

Dispersing chelating agent ARSK0.3kg/L

Levelling agent CE 4001g/L

Penetrant JFC 0.5g/L

ARSK, CE 400, and JFC were formulated to a concentration of 10%, that is, 100 mL of the original solution was prepared to 1000 mL. The total amount of proofing was calculated as 50 mL. Then, ARSS 0.15 mL, CE 400 0.5 mL, and JFC 0.25 mL were added.

2.2 Specification dyeing process

(1) Disperse dyeing process

60 °C into the dye (added HAc, diffusion agent NNO, levelling agent 1011, dye), heated to 130 °C at 2 °C / min, heat 30min, cooling, remove, wash → dark reduction cleaning → rotten cotton → compared with the original

(2) Shanghai Wande B dye dyeing process

60 °C into the dye (add dye, disperse chelating agent ARSK, leveling agent CE 400, penetrating agent JFC, Yuan Mingfen, insulation 20min, then add soda ash, heat 55min), cooling, remove, wash water → pickling → washing → soap Washing (add soap liquid 100°C×3min) → Wash → Drying 2.3 Control sample bath ratio

Whether the cheese yarn dyeing is consistent with the customer sample request, the sample test is the key. Whether the color and shade are accurate, whether it meets the requirements for sampling, whether the bath ratio is 1:10, whether the process is reasonable, and whether it can play a guiding role for large samples, directly affects the qualification rate of dyeing. In the 1970s, the first generation of small sample machines represented by the connecting rod type had large noise, long dyeing time, and great differences in the process conditions and large sample production. In the 1980s, the RJ 1180 high-temperature and high-pressure dyeing machine was used for dyeing. The bath was relatively large, generally at 1:40, so there was no rule to follow. In the 1990s, represented by domestic SCD2 12 140 type high temperature and high pressure sampler, the machine used high boiling point oil as the heating medium. After entering the 21st century, a sampler heated by a photocell is popular. The dyed sample is uniform in color, and the bath ratio is comparable to that of a large prototype, and the effect is also good.

2.4 Master Device Performance

The sample process conditions should be as close as possible to the large production process. The same dyeing prescription will produce different dyeing depth differences on different equipments. Even the dyeing equipments of two identical models will have different dyeing colors. This requires a full assessment of the various factors that influence the color development of dyes in production. To grasp the performance of the equipment, take appropriate technical measures for color prescriptions and process conditions, and make sure that the dye liquor is properly and fully recycled in the loose tube to ensure the dyeing quality of the cheese. The pressure of the dyeing solution is determined by the pump head, too low to penetrate, too high to increase energy consumption, and to confuse the yarn, depending on various equipment. In addition, there must be a reasonable positive and negative circulation. The density of the dyeing fluid in the bobbin during dyeing decreases with the increase of the bobbin radius. If it is not compensated, it will cause the outer shallow depth. The circulation direction of the dyeing liquor can be designed as: positive circulation (from inside to outside) 1 to 1.5 minutes, reverse circulation (from outside to inside) 2 to 3.5 minutes.

2.5 Winding density

The proper and uniform loose bobbin winding density is very important for the quality of cheese dyeing. The density is appropriate so that the dye liquor penetrates the yarn. The bobbin is too loose. When the yarn meets water, it will deform from the bobbin. The upper and lower ends will collapse or the dyeing liquid will only penetrate between the yarns without penetrating between the fibers. The density of bobbins should be determined according to factors such as different fibers, yarn count, and dyeing process. The density is required to be uniform. If the density is not uniform, the dyeing liquid will flow to places with low resistance and low density, or even a “short circuit” occurs. The yarns in this place will be in contact with the dyeing solution, and the color will be dark; otherwise, they will be shallow and may even appear. White track.

3.1 Selection of dyes

There are many kinds of dyes used in cheese dyeing, and the dyeing properties of different dyes are different. The color is also inconsistent. We must choose dyes with good application properties, good fastness, and can guarantee the appearance of good color varieties to achieve the best level of dyeing Sex.

According to the production experience, we recommend the following dyes for cheese dyeing:

(1) Shanghai Wande B-type dye red B 6BF, blue B 2GTN, yellow B 6GLN, brilliant blue B RV.

(2) Dystar 2R dye (light color) Red 2R, Yellow 2R, Blue 2R.

(3) Yagegan EC type dye red EC, red light black JFWP, R, black navy blue B150%, yellow EC, glaucoma black JFWP, red BF DB 200%, navy EC, brilliant blue RCDEC, yuan BN.

(4) Coswain dye red 3BSN, navy blue B133, black GWF, yellow 3RS, turquoise blue ED G200%, navy blue 2G, navy blue BF, Yuanqing N.

(5) Japan East Cotton Chemicals CF type dye Red CF 3B 150%, Blue CF G150%, Yellow CF 3R150%, Tibetan Green CF B.

(6) Disperse dyes Dahong SR, Yuan H3BL, Zi HFRL, Hongyu S 5BC, Huang SE 5R, Brilliant Blue S BL, Nenhuang SE 4GLN, Cuilan S GL, Dark Blue HGL 150%, Orange S 4RL, Red 3B.

3.2 Selection of fight color dyes

When formulating the dyeing process, choose a colorblocking dye that is compatible. After dyeing with a single dye, the hue and shade after dyeing are relatively stable. Even if the difference occurs, it is only a difference in shade, and it is relatively simple to adjust or repair. The possibility of color changes in the two dyes is large, but it is easier to adjust, and only one of the dyes can be adjusted. The use of three dyes to fight color, especially the use of three primary color dyes for color matching, has increased the possibility of occurrence of color change and has made it difficult to adjust or rework additions. Therefore, the number of dyestuffs should be as few as possible.

(1) Use CF type dyes to dye medium and light colors, use red, yellow, and blue to fight colors. Do not use Navy CF B to fight colors. Use dark red, yellow, and dark green to fight colors when dyeing dark colors.

(2) Dyeing with Cossackin dyes. Generally, light-medium color is used to fight color with navy blue BF. Dark color is used for navy blue BI33 as the main color to fight color. Green does not have to use turquoise blue ED G, but use navy blue 2G.

(3) Dyeing with Shanghai Wande B dyestuff, the red B 6BF is not suitable for cheese dyeing, and it is best to replace it with BF DB 200%.

(4) Dyeing with disperse dyes, light-colored varieties with low temperature type 3B red 3B, yellow SE 5R, blue 2BLN are three primary colors; medium and dark color varieties with high temperature type Ruby S 5BL, orange S 4RL, dark blue HGL are three primary colors; H3BL is a high-temperature blending dye, and it is not suitable to use low-temperature three-primary color matching; dark blue, dark green and dark yellow brown are best used with high-temperature dyes to improve color fastness.

3.3 Additive quality

Many types of additives, if used improperly, will make the dye on the yarn color difference, resulting in inaccurate and unstable color. For example, when disperse blue 2BLN and disperse yellow SE 5R are used to fight green, because disperse yellow SE 5R is more sensitive to pH value, if there is quality problem of glacial acetic acid in the dye bath, or the content is insufficient, the pH value is high, and after dyeing, the color will be high. Causes yellow color and blue light. Other auxiliaries, such as leveling agents, chelating agents, penetrants, and fixing agents, also have batch-to-batch differences in concentration and impurity levels. Therefore, it is required to test each batch of incoming goods and establish a system of dyeing and filing materials.

3.4 Additives

In order to standardize operation and ensure the stability of shade, according to the different nature of various dyes, the amount of Yuanming powder and soda ash shall be separately specified (Table 1 to 5).

Finishing process flow seam → Singe → Desizing → Mercerizing → Drying → Forming → Shrinkage proofing

4.1 Effect of Mercerization on Dyeing Quality

4.1.1 strictly control mercerizing speed

The dyeing combing poplin mercerizing speed is 45-50m/min, and it is determined that it takes 50s from the rolling alkali tank to the first-rinsing alkali area, which is favorable for the penetration of the cotton fiber and plays a good mercerizing effect.

4.1.2 Selecting the appropriate alkali concentration

Theoretically speaking, 130g/L alkali concentration can produce a sheen luster, with the increase of alkali concentration, the gloss is also correspondingly enhanced; but when the alkali concentration exceeds 300g/L, the gloss is reduced instead. Considering comprehensively, the setting of general dyed grey cloth and alkali concentration is shown in Table 6.

4.2 Effect of Shaping on Dyeing Quality

4.2.1 Strictly control the setting temperature and speed

Yarn type of poplin poplin products are generally controlled at 170 °C ~ 185 °C, speed 40m/min or so, will not affect the quality of dyeing.

4.2.2 Mastering Color Correction Techniques

For some batch color, a slight color difference can be solved by shaping. For example, if the whiteness is not enough, polyester whitening agent or cotton whitening agent can be added in the rolling tank; disperse blue-violet can also be added to improve whiteness.

In short, there are many factors that cause inconsistency in sampling and the color difference in batches. It varies depending on the production conditions of each plant. After taking the above measures, the yarn-dyed fabrics produced by our factory can meet the strict production characteristics of small batches, multiple varieties, and color differences. The pass rate and once-success ratio of set-out are significantly increased, the production cycle is shortened, the cost is saved, and the finished products and foreign trade come The color difference is more than 4 levels.

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