Dyeing and finishing process of modal/spandex knitted fabric

[Abstract] Abstract: Modal fiber is a kind of high wet modulus regenerated cellulose fiber with low dry and wet elongation, high wet modulus, high purity, low water content, good alkali stability and good affinity for dyes. . Modal and spandex fabrics can be dyed with reactive dyes. Because they are sensitive to dyeing materials, they are prone to hairiness, abrasion, creases and other defects during dyeing and finishing. Therefore, slow rise and fall temperatures should be adopted during processing. Dyestuffs, Yuanming powder, and soda ash should be added in divided portions. Modal knitwear is very comfortable to wear, but it has the disadvantage of easy surface raising and pilling. It can be finished according to the requirements of Modal products (such as polishing, softening, antistatic, anti-pilling, etc.).

Modal fiber is made from European eucalyptus, and the new generation of regenerated cellulose fiber with high wet modulus made by spinning is a special viscose fiber, which not only has the hygroscopicity of natural fiber, but also has synthetic fiber. Strongly flexible, more importantly, the fiber is clean and non-toxic, and its textile waste can be naturally biodegraded. It has good environmental performance and has been promoted by the textile industry and garment manufacturers as the 21st century. One of the potential green fibers. In addition to some of the characteristics of viscose fiber and cotton fiber, modal fiber also has its unique characteristics. The fabric made of modal fiber has a silky luster, high-quality mercerized cotton style, and the hand feels delicate and soft. Drapability and wearing performance are very good, modal / spandex knitwear also has good elasticity, is the first choice for high-end apparel fabrics. However, in the dyeing and finishing process, Modal knitted fabrics are prone to scratches, creases, unstable width and mass, and the fabric surface is prone to hairiness and pilling. It seriously affects the quality of the fabric and reduces the fabric. Grade. In response to the characteristics of Modal fiber, our company has launched a set of pre-treatment, dyeing and finishing processes through trial and error, so that the performance of modal fiber can be better played.

1 Â Dyeing and finishing process

Blank inspection â†’ seam head â†’ predetermined shape â†’ buckle edge (front side inward) â†’ scouring â†’ polishing â†’ dyeing â†’ soaping â†’ drying â†’ soft finishing.

2 Â Dyeing and finishing process conditions

2.1 Â Predetermined shape

In order to prevent shrinkage under the pre-treatment of hot and humid conditions, reduce the occurrence of fine lines, and set the temperature at 195 Â° C, the vehicle speed is 15 to 20 m / min.

2.2 Â Pretreatment

The modal fiber is finer than the cotton fiber, and the fineness of the 1.3 tex modal fiber is equivalent to the fineness of the cotton of 1.7 to 1.8 dtex, the cross section of the fiber is uniformly circular, and the longitudinal direction has no three-dimensional crimp similar to that of the cotton fiber. As the number of cross-sections of the yarn increases, and the surface of the fiber is smooth, more fiber ends are released from the yarn during wet finishing and taking, which tends to pilling the surface, so it is required in various processes. It is possible to maintain low tension and low speed to reduce friction, thereby reducing the occurrence of fluffing, pilling and hole-breaking. In the actual production process, you must pay attention to the following points:

a The process must be completely dip;

b. The front side of the fabric is folded in half and buckled, so that the front side of the fabric is processed inwardly to reduce the friction between the fabric surfaces;

c. Use a larger bath ratio as much as possible, adjust the bath ratio from 1:10 to 1:12 according to the fabric, and add a softener in the antistatic bath in the bath to reduce the mutual friction between the fabrics;

d. In the process of bleaching, dyeing and finishing, the fabric maintains a gentle state of motion, controls the temperature, avoids the phenomenon of waterfall boiling, and controls the rotation speed of the dyeing machine.

2.2.1 Cooking and bleaching one bath process

Knits of modal and spandex fibers generally do not require bleaching, as long as they are slightly scoured to remove the oil and wax from the spinning and weaving process. If the products used for dyeing bright colors or modal and cotton blends are mostly bleached, in order to save energy and reduce production costs, the bleaching process should be based on the composition ratio of the fabric.

Cooking and bleaching one bath process:

Multifunctional pretreatment agent JINSCOUR ^Â® EX 2g/L

Antistatic bath softener JINSOFT ^Â® 3988 1~1.5g/L

50% H ₂ 0 ₂ 3ï½ž5g/L

NaOH 2ï½ž3g/L

pH value 10.5ï½ž11

Bath ratio 1:15

Temperature 85ï½ž90Â°C

Time 45~60min

The process curve is shown in Figure 1:

Figure 1 boiling and bleaching process curve

2.2.2 scouring process

If the modal/spandex knitted fabric is dyed with dim color, the pretreatment has low requirements on the whiteness of the fabric, and it is only necessary to scouring and remove the spinning oil and wax.

Ordinary scouring process:

Multifunctional pretreatment agent JINSCOUR ^Â® EX 2g/L

Bath ratio 1:10

Temperature 85ï½ž90Â°C

Time 20~30min

The main component of the multi-functional pretreatment agent JINSCOUR ^Â® EX is a nano-dispersion and surfactant compound, white viscous non-/anionic ionic structure, pH 7-8. The product has a unique degreasing ability and fiber protection, low foam, and does not contain APE0. The scouring with a multi-functional pretreatment agent eliminates the need for alkali and avoids the scouring of the alkali to cause damage to the fiber.

Antistatic bath softener JINSOFT ^Â® 3988 is a high molecular polymer, transparent mucilage, non-ionic structure, neutral, can impart good lubricity between fiber and fiber, fiber and mechanical parts, can effectively prevent fabric dyeing and finishing Scuffs, creases, no bubbles generated during the process, good compatibility with other auxiliaries, easy to clean.

2.2.3 Polishing

The modal fiber structure determines the hairiness of the fabric surface. The long-term wet heat treatment makes it easier to expose the fiber yarn tail end, and it is easy to pilling during the taking process. The polishing process utilizes cellulase to remove the fluff on the surface of the fabric, so that the surface of the fabric is smooth and smooth, thereby reducing the phenomenon of raising the ball. The polishing treatment can be carried out before and after dyeing.

Processing process:

Polishing enzyme BPF 0.6%~1.0%

HAc adjusts the pH to 5~6

Temperature 50ï½ž55Â°C

Bath ratio 1:10

Time 30~40min

The process curve is shown in Figure 2.

Figure 2 polishing process curve

After being treated by the above process, the modal/spandex fiber knitted fabric has good whiteness and hair effect, and the fiber is well protected, no crease is generated, and pilling is not easy to be pilling, which ensures the style of the product.

2.3 Â dyeing

Modal fiber is a kind of cellulose fiber, so it has similar dyeing properties to viscose fiber and cotton fiber, and can be dyed with reactive dye and direct dye. However, due to the particularity of Modal fiber, it is sensitive to dye additives, and has strong affinity for reactive dyes. It has high initial dyeing rate and short half-dyeing time. Once the dye is dyed, it is not easy to be dyed, and it is easy to produce color flowers and Color spots. Therefore, pay attention to the following points during dyeing and finishing:

a. Choose dyes with good reproducibility, compatibility and levelness, and medium directness to modal fibers (optional DyStar's Ramazin dye);

b. The dye, Yuanming powder and soda ash should be added in several stages, and the process curve shown in Fig. 3 is adopted;

C. Yuanming powder is easy to agglomerate, so Yuanming powder and soda ash should be slowly added to the dyeing solution to prevent uneven distribution on the fabric;

d. Pay attention to the change of water hardness, if the hardness does not meet the requirements, add a softener;

e. Detecting whether the pH value of the dyeing solution in the range of 10.8 to 11.2 when the reactive dye is dyed;

f After the fabric is boiled and bleached, it is generally necessary to use oxygen scavenging enzyme to remove residual hydrogen peroxide, otherwise it will easily cause color flowers;

g. For dyeing deep colored fabrics, it is necessary to fix the color after soaping.

Modal fiber dyeing process prescription:

Dye x%

Cotton leveling agent JINLEVEL ^{Â® Â} CD 0.5ï½ž1.0g/L

Antistatic bath softener JINSOFT ^{Â® Â} 3988 1~1.5g/L

Yuanming powder 5ï½ž60g/L

Soda ash 5ï½ž20g/L

Bath ratio 1:10ï½ž1:12

Figure 3 dyeing process curve

Cotton leveling agent JINLEVEL ^Â® CD is a special non-anionic surfactant compound with excellent wetting, dispersing, retarding, alkali, salt, hard water, low foam and dye Solubility, effectively preventing color points, color defects, and the like. The modal fabric is dyed by the above process, and the color is uniform, the color is bright, the cloth surface has no creases, less hair, and the hand feels soft and smooth.

2.4 Â Soft finishing

The finishing of the fabric is critical, and the grade of the product depends to a large extent on the quality of the finishing. The cross section of the modal fiber is evenly rounded, and the cohesion between the fibers is worse than that of the cotton fiber. If the conventional amino silicone oil smoothing softener is used for finishing, it tends to reduce the cohesion of the yarn more or less, so that the fabric surface It is easier to pilling. Therefore, the soft process and the softener will determine the feel of the fabric and the style of the product. The biggest drawback of Modal fabrics is the pilling, and the pilling has a certain relationship with static electricity. Therefore, an antistatic agent and an anti-pilling agent can be added for the composite finishing in the finishing process. Modal and spandex fabrics have a full and soft hand, good drapability and luster. In order to further improve the grade of the product, the fabric is soft and smooth. After many trials, the following soft formula can be used to make the fabric very good. The hydrophilicity also gives a special cool feel and a body feel.

Soft process:

Silk fabric finishing agent JINSOFT ^Â® WNS 40g/L

Anti-pilling finishing agent JINSOFT ^Â® 6750 40g/L

Setting temperature 160ï½ž175Â°C

Overfeed 20% to 25%

Speed â€‹â€‹15~20 m/min

3 Â in conclusion

Modal fiber is a kind of regenerated cellulose fiber. It not only has the characteristics of natural fiber, but also has the characteristics of some synthetic fibers. It is non-toxic, non-polluting and degradable. It is a kind of green fiber with its unique performance. The modal fabric after the addition of spandex is prone to scratches, creases, unstable width and gram mass, and the fabric surface is prone to hairiness and pilling. Choosing the right processing technology is the most critical.

a. The modal and spandex fibers are scoured by the multi-functional pretreatment agent JINSCOUR@EX, and the fiber is less damaged. The surface of the fabric is not easy to pilling, and the original characteristics of the fiber can be maintained, and the damage of the modal fiber by the strong alkali pretreatment is avoided.

b. In the pre-treatment and dyeing, the antistatic bath softener JINSOFT ^@ 3988 is added to prevent the fabric from being scratched, hooked, creased and unevenly dyed during the whole process.

c. Add the cotton leveling agent JINLEVEL ^@ CD during the dyeing process to make the dye evenly dispersed. After dyeing, the fabric has uniform color and bright color.

d. The soft silk fabric finishing agent JINSOFT ^@ WNS is used in the softening process to further obtain a good hydrophilicity and fullness, softness and smooth hand feeling, and has an antistatic function, thereby improving the wearing performance of the product.

e. Strengthening and finishing, such as adding anti-pilling pilling agent, etc., to further improve the wearing performance of the fabric.

Â references:

(1) He Liqing, Kang Yuehong: â€œDyeing and Finishing Practice of Modal Knitted Fabricsâ€, Knitting Industry, 2006 (2), 37-38.

(2) Liang Jiaxuan: "Dyeing and Finishing of Modal Fabrics", Knitting Industry, 2003 (4), (56-59)

(3) Peng Zhizhong: "Dyeing and Finishing of Modal/Cotton Elastic Knitted Fabrics", Printing and Dyeing, 2007 (8), 16-17

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