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Fabric class ---- What is space dyeing? How should fabric dyeing work?

Date:Sep 21, 2020

1. What is space dye

 Space dyeing refers to dyeing two or more different colors on a twisted yarn or fabric.

 

The Space-dyed products are novel and unique, and the style of the fabric woven by the Space-dyed yarn has been fundamentally broken, so it is deeply favored by consumers.

 

The yarns suitable for Space dyeing are: cotton, polyester cotton, acrylic cotton, viscose staple filament, acrylic, rayon, polyester filament, pure plush thread, nylon thread, nylon staple filament and various blended yarns , The dyes that can be used for Space dyeing are: reactive dyes, acid dyes, disperse dyes, paints, etc.

Space dyeing

2. Space dyeing method

 

The space dyeing method can be mechanical space dyeing or original manual space dyeing. Mechanical space dyeing can be divided into direct space dyeing and indirect space dyeing.

 

There are also many equipment for mechanical dyeing, and there are equipment that can dye up to six colors at a time, which is an integrated dyeing and fixing. There are more and more people studying space dyeing technology, and the mechanical materials, auxiliaries and technology of space dyeing are also constantly developing.

 

For a long time, yarn-dyed fabrics have been woven by dyeing yarns and then arranging the yarns in a designed pattern. The woven fabric is neat and regular. Since each yarn has only one color from beginning to end, the style of the woven fabric is monotonous and uninspiring. Therefore, after extensive experimentation, practice, and summary, we have designed as many as Yarn-dyed products woven from six-fold dyed yarns. The colorful and changing styles of the fabrics are named Symphony Yarns.

 

(1). Pure cotton

CJ14.6/14.6 472/314.5 (CJ5.8×2+CJ11.7)/(CJ5.8×2+CJ11.7) 629.5/354

 

(2). Polyester cotton

T/CJ7.3×2/13 464.5/307 T/CJ13/13 472/314.5

 

(3). Low proportion polyester and cotton blended class (CVC)

CJ/T7.3×2/7.3×2 456.5/314.5

 

Process flow:

Warp yarn and weft yarn: cheese yarn → skein → boiled yarn → dyeing → winding

Warp yarn: warping → sizing → drawing-in reed

}→Weaving→Blank inspection→singeing→washing→(mererized)→soft setting→pre-shrinking

 

Weft: ------------------

This kind of magic yarn is a new breakthrough in yarn-dyed fabrics, and using segment-dyed yarns to research and design fabrics will also have a greater breakthrough.

 

3. Direct space dyeing

 

Before space dyeing, the hank yarn undergoes pretreatment such as desizing, scouring, bleaching and bleaching. Pay attention to the amount of alkali. Too much will easily reduce the yarn strength, and too little impurity removal effect is not ideal, which will affect the space dyeing effect and the woven fabric The quality of the noodles. The wool efficiency of the yarn after scouring is not less than 8cm/30min, and the pH is 7-8. Too low wool efficiency will affect the penetration of the color paste and cause poor dyeing; too high will easily cause bleeding and unclear contours, which will affect the pattern after weaving.

 

(1). Coating space dyeing of cotton yarn

 

The paint space has complete dye spectrum, convenient color matching, stable color and light, not easy to penetrate, clear outline, simple process, and the disadvantage is that the hand feel is hard.

 

1.1 Process flow:

 

After scouring, the yarn is spray-printed and dyed and then steamed (100-102℃, 5-10min)-washing-drying-sizing

 

1.2 Process points:

 

Adhesives: Use cross-linked adhesives, such as screen printing adhesives, which have good film-forming feel, high scrubbing fastness, and high temperature non-yellowing. The amount should be determined according to the concentration of the paint in the color paste. Less fastness;

 

Emulsified paste: use oil-water type emulsified paste;

 

Coating: The particle size is between 0.2-0.5um. When the particle size is too large, the hiding power is poor, the abrasion resistance is poor, the color tone is dim, and the shade is reddish; when the particle size is too fine, the vividness decreases, the amount of color is reduced, and the paint color paste is easy Produce agglomeration phenomenon;

 

Urea: Add urea to the color paste, the color paste becomes thinner, the viscosity decreases, the color paste is more stable, not easy to form a film, use as little as possible, otherwise it will reduce the fastness, and cause serious bleeding at the edge of the dye during steaming;

 

Cross-linking agent: adding a cross-linking agent can improve abrasion resistance and scrub fastness, but the dosage should be strictly controlled, too much will affect the feel. The method of space dyeing is similar to that of fabric printing.

 

1.3 Attention points in the process:

 

In order to make the space dyeing part impermeable, the dye is mixed into a color paste, which is sprayed onto the yarn through the space dyeing machine. The temperature during drying is not easy to be too high, and the yarn should be 80% dry when leaving the drying room. The paint stage dyeing process is simple and the dye utilization rate is also high, which is also a good stage dyeing method.

 

2. Reactive dye space dyeing of cotton yarn

 

The reactive dyes have complete chromatograms and excellent dyeing fastness. The dyeing of pure cotton yarns mainly uses KE type reactive dyes. However, it is found in the production that if KE type is used for space dyeing, the washed dyes are easily contaminated, resulting in fast dyeing. It may be that the KE type is a double-reactive base type, and the reaction activity is greater than that of the K type. Unreacted dyes and hydrolyzed dyes are easy to contaminate during washing. For this reason, use K type dyes for printing, which is reasonable in price and convenient to use. A satisfactory fastness can be obtained.

 

2.1 Process flow:

 

After scouring, the yarn is sprayed and dyed and then steamed (100-102℃, 5-10min)-washed-dried-sizing.

 

2.2 The main points of the process are as follows:

 

When steaming, wrap the yarn with dry cloth to prevent bleeding;

 

The use of medium viscosity seaweed pulp is conducive to the color paste spraying from the nozzle and penetrating into the lower yarn. When the pulp is adjusted, 0.25%-0.5% sodium hexametaphosphate can be added to prevent the influence of calcium ions, and at the same time adjust the pH with soda ash =7-8, the whole paste requires no agglomeration;

 

Urea plays the role of wetting and dissolving, because the yarn is directly steamed after being sprayed with dyed slurry without drying. When the amount of urea is large, it will cause serious permeation. You can add some for dark colors, and not for medium and light colors;

 

Baking soda is used as an alkali-releasing agent. When toning, you should wait until the temperature of the paste is lowered to room temperature before adding it, otherwise a large number of bubbles will be generated in the color paste and the stability of the color paste will decrease, which will affect the amount of color and color fastness;

 

The dissolution temperature of the dye does not exceed 90℃, and the dye fastness of reactive dyes is good and the hand feel is good. Therefore, in general, reactive dyes are used more frequently.

 

2.3 Examples of specific space dyeing process:

 

B-type reactive dye direct dyeing process.

The orange segment dyeing process refers to the textile printing method. In order to make the segment dyed part impermeable, the dye is mixed into a color paste, which is printed on the hank through a pad printing method, and then undergoes appropriate post-treatment to fix the dye.

 

(1) Process flow: rolling joint → drying and fixing (115℃, 1.5h) → post-treatment [detergent 1% (owf); 100℃, 5-10min].

 

(2) Duan Dianyuan paste process prescription:

Sodium hexametaphosphate 6 g/L

Soda ash 4 g/L

Sodium alginate 48 g/L

Process conditions:

Gelatinization temperature 60~70 ℃;

Time 3 h

PH value 7~8

Orange segment dyeing pulp process prescription:

Reactive Yellow B-3RD 3.6 g/L

Reactive Red B-4BD 0.52 g/L

Reactive Blue B-GD 0.012 g/L

Urea 50 g/L

Baking soda 15 g/L

Original paste 200 mL

 

2.4 Dyeing process parameters:

 

Color space length 3 cm

Number of stamping 8 times

Keep bottom center distance 16 cm

 

Note: In the entire printing process, drying and fixing is the key, the yarn after knitting must be dried, otherwise the post-processing process will cause coloring, staining, and secondary yarn.

Direct space dyeing

4、Indirect segmentation

 

In recent years, multi-color pile dyeing has been widely used in wool spinning enterprises. This equipment directly dyes pure plush yarn, pure nitrile yarn, wool and nitrile blended yarn, etc. According to the frame length of the skein, the length of the color space and the separation distance can be changed to design a special style and colorful space dyeing pattern. The space dyeing of pure plush yarn is an indirect space dyeing, which is a space dyeing yarn made with anti-discharge technology.

 

(1). Features

The wider the color segment of space dyeing, the greater the consumption of color paste; the darker the color, the greater the amount of dye, which is too wasteful of dye;

 

The thickness of the dyed yarn in the hank space cannot be absolutely uniform, and the color will be different when the thickness is different with the same pressure roller;

 

As the space dyeing width increases, the color difference between the front and back sides also increases, which reduces the quality of space dyed products. These problems can be solved with anti-discharge technology.

 

(2). The principle of anti-discharge technology applied to dyeing of pure plush line:

 

The pure woolen yarn is first dyed with acid dyes in the hank liquid dyeing machine for the background color, and then dyed with a white paste or color paste containing a discharge agent to destroy the background dye, and the white space of the color background is called plucking White; dye the new color segment while destroying the background color, and the color segment of the color background is called color pull. Wool fibers are not resistant to strong alkalis, but have certain resistance to acids. Therefore, acid discharge agents should be used as far as possible to prevent discharge of pure wool yarn.

 

(3). The choice of color discharge dyes for background dyes:

 

The base color dye should be easily damaged by the discharge salt, and it has good dry and wet rubbing and washing fastness; the color discharge dye should not be damaged by the discharge salt with good light fastness.

Indirect segmentation

(4). A simple method to test the resistance of acid dyes to discharge salt in the laboratory:

 

Prepare 100g/L dye discharge salt solution, take 100mL and heat to 100℃, add 1 g/L dye solution drop by drop, observe the damage of the dye. Dyes whose colors disappear quickly can be used as background dyes, and those that do not change for a long time can be used as color discharge dyes. Tested: ①Acid black ATT, ②Acid navy blue GGR, ③Acid yellow 2G, ④Acid brilliant red B, ⑤Acid fuchsine 6B, ⑥Weak acid brilliant red B, ⑦Weak acid brilliant Red 10B, ⑧ weak acid black BR, etc.; can be used as color discharge dyes: ①Pura Yellow GN, ②Acid Rose Red B, ③Acid Blue BGA, etc.

 

(5). Dosage of discharge salt:

 

The darker the background color, the greater the amount of discharge salt; the stronger the ability of the dye to resist the discharge salt, the greater the amount of discharge salt; the greater the amount of discharge salt required for whitening or bright color segments. General In terms of: the dosage of discharge salt is used between 50-100g/l, if necessary, it is determined by the actual production.

 

(6). Process flow:

 

White velvet yarn → washing thread → dyeing the background color (skein flow dyeing machine) → dehydration → thread management → white drawing or color drawing space dyeing (six-color line continuous space dyeing machine: atmospheric spray drawing dyeing pulp; steam The steaming temperature is 100 ℃, and the steaming time is 10 min; rinse with water) → softening → dehydration → drying → moisture regain → finished product. The production process of anti-discharge space dyeing of pure plush thread is exactly the same as that of ordinary pure plush thread.

 

(7). Examples of color plucking of pure plush thread:

 

Take the pure plush thread (46.3tex×4) dyed with safflower and gypsophila on black as an example. Total yarn length 80cm

⑴Black background ⑵Red segment ⑶ Black background

图片1

Raw materials for background dyeing:

 

Acid black ATT 5 kg

Sulfuric acid 5 kg

Yuanming powder 5 kg

Wool yarn 100 kg

The dyeing process is exactly the same as that of pure wool yarn with strong acid dyes.

 

Color discharging paste formula:

 

Acetic acid 1000 ml

Discharge salt 8000 g

Acid Rose Red B 400 g

Penetrant JFC 1000 g

It should be noted that the dye must be added before use after it is cleaned with hot water; the temperature of the color paste should not be too high and should be used up in the shortest possible time, otherwise the color of the color paste may gradually become lighter.

 

Pure plush line segment dyeing equipment: six-color velvet line segment dyeing machine.

The space dyeing operation is basically the same as that of conventional pile space dyeing.

 

(8). Points to note during operation:

 

Shake and straighten the background yarn first, and try to open the skein. The thinner the wool is flat, the better, and feed it into the space dyeing machine one by one, so that there is no overlap, no gaps, continuous blocking and no disconnection between the twist and the twist;

 

Before space dyeing, check whether the steam pressure is stable. After turning on the steam, you must wait for the steam box temperature to reach 100 ℃ before driving;

 

During the production process, do not speed up or slow down arbitrarily, and do not stop at random during dyeing at constant speed and constant temperature, especially in the steamer. The dyeing effect of preventing wool yarn is different. The anti-discharge technology is applied to pure plush line dyeing, which can enrich the variety of patterns dyed with pure plush line, increase sales and improve economic efficiency. The application of this kind of anti-discharge technology has given a new development direction for space dyeing technology.

 

5、Hand-dyeing example

 

1. space dyeing equipment and basic preparation:

 

Using an open dyeing pot, a free-lifting bracket is made on the dyeing pot, so that the rayon can be lifted up and down by hanging on the bracket. The general color of the segment dyed yarn is from light to dark. If there is no white (white space), light color can be used as the base. If there are three colors, first divide the viscose yarn into three according to the length of the skein, and use polyester yarn to divide into three. The segments are tied tightly as a dividing line.

Before dyeing, make the yarn fluffy to prevent the dye from being fully dyed to the yarn during dyeing. Dyeing is divided into spaces. The reactive dyes are easily hydrolyzed at high temperatures and require warm hydration materials. The amount of water is calculated according to the bath ratio. Add water and steam to raise the temperature. The dyeing temperature of general dyes is 60℃, and some dyes need to be dyed at 80℃.

 

2. Process flow:

 

Put 1/3 of the yarn into the dye liquor for dyeing → add sodium sulfate after 20min → add soda ash after 20min → wash with water after 20-30min.

 

3. Points to note during the dyeing process:

 

When the temperature reaches the requirement, moisten one third of the hank yarn and then put it in the dyeing liquor to start dyeing to prevent the dye from moving up;

 

During the dyeing period, make sure that the yarn is swaying constantly to prevent the yarn from blooming. The swaying amplitude should not be too large, otherwise the dye will be dyed on the yarn that does not need to be dyed;

 

The purpose of adding sodium sulfate is to promote the dyeing of the yarn faster. At this time, it also needs to keep shaking. Adding soda ash to keep the color fixed, during this dyeing period, it is necessary to ensure that the yarn shakes regularly, otherwise it may be possible Resulting in yarn discoloration. This kind of dyeing method adopts one-bath method of dyeing and fixing, and it should be washed (rinsed) immediately after dyeing, in order to remove the floating color on the surface. The same is true for the other two-stage dyeing methods. Soaping and washing are carried out after all the yarns are dyed;

 

The fixing time is determined according to the depth of the color, dark colors need to be kept warm for a while, light colors do not need too long, generally 20-30min;

 

If the yarn has white space or floating color contamination in the white space, use 1g/L Sodium Sulphate and 2g/L soda ash to remove the floating color at about 70℃;

 

The dyeing time of space dyeing should not be too long, otherwise it will affect the effect of space dyeing. Because the dyeing time is short, the dye uptake rate is low, the utilization rate of dyeing materials is low, waste and pollution are more serious, so the application of the stage dyeing process is not very frequent. space dyeing of other types of yarn methods is also to be studied.