Knitting, bleaching and dyeing of knitted fabrics are generally performed in overflow tanks. During the entire processing process, the fabrics are kept in a rope state. The fibers are constantly bent and deformed in the dyeing machine, and the original hydrogen bonds are continuously destroyed, and new hydrogen bonds are continuously formed. In some cases, the newly formed hydrogen bonds do not fully recover, and chicken paw prints and dead creases are formed on the surface of the fabric. In the single-fabric structure, the tension on both sides of the yarn is asymmetric, and it is difficult for the fabric to recover after a long period of one-way crease. Therefore, fine wrinkles are more likely to occur in various structures such as plain weave, sweater, and single bead. The occurrence of fine wrinkles is also related to yarn count and twist. The younger the yarn, the higher the twist, the greater the reversal of the yarn, and the greater the reflection of fine wrinkles.
The general process of dyeing and finishing is: cloth preparation → sewing head → falling cylinder boiling → dyeing → soaping → fixing color → softening → cylinder discharge → dehydration → shock wave machine or dryer cloth, and the formation of fine wrinkles is mainly In dyeing vats, dehydrators, and stackers, depending on their formation conditions, improvements are mainly made from the following aspects:
1. Preset type
By adjusting the fiber proximity and degree of orientation through a predetermined pattern, the microstructure and morphology of the fabric change during heat setting of the fabric. When the fabric is shaped, the fabric is fully stretched and fixed under high temperature, the fiber shape is fixed, and the occurrence in the dyeing tank is reduced. The chance of change helps reduce creases.
2. Elimination of internal stress before falling cylinder
After the loose cloth is fully relaxed in the stacker, the grey cloth is generally stored in the warehouse, and the relative humidity in the warehouse is low. The cloth is stacked together in a very dry state for a long time, and it is easy to produce indentation. Placed in a place where the humidity of the workshop is relatively strong, the fiber swells when the moisture regains, and the internal stress is partially eliminated.
Through the J-shaped groove to eliminate, loose cloth after allowing it to freely through the J-groove, while pressing or roller roller extrusion, the original hydrogen bond changes, is conducive to the elimination of internal stress;
Through the use of stretched and overheated hot water to reduce creases on fabrics, knitted fabrics are generally cylindrical and can be widened by a cloth guide loop. At the same time, wet steam or overheated water tanks are used to reduce creases. When the cloth is fully wetted, certain penetrants and smoothing agents may be added.
3. Bleaching and dyeing
Pay attention to the amount of dyeing cloth capacity, dyeing should generally be reduced by 10 to 15% in accordance with the provisions of the dyeing cylinder, must not be overloaded operation, when the cloth is too large, the fabric in the storage tank pressure is serious, can not be stretched at the nozzle, very It is easy to form indentations;
Pay attention to the heating and cooling rate, when the heating or cooling rate is too fast, the temperature of the cloth body is likely to be uneven, and when it is concentrated on the fiber, the degree of coldness and heat of the fiber is different, and the shrinkage is uneven, especially when the temperature is decreased, the partial quenching is easy. The form is cured, forming a wrinkle that is difficult to eliminate. Therefore, after the high temperature process, generally to a rate of 1 ~ 1.5/min cooling to 70 °C drainage, or directly after the high temperature process into the cold water overflow until the temperature is reduced and then completely drain;
Lubricants are added to dyeing baths to reduce the friction between fabrics and between fabrics and machinery, thereby reducing the chance of wrinkling. However, the choice of smoothing agent needs to take into account stability, compatibility with processing procedures, etc. to avoid lubricants. Improper selection creates other problems;
Selecting more advanced machinery, increasing the width of the storage tank, and lowering the height of the lifting drum are all beneficial to reduce the pressure on the cloth body. When the air cylinder is selected, the fabric is blown open by the high-pressure gas at the nozzle, and the fiber is obtained under tension. "Relaxation" is conducive to the elimination of internal stress.
4. Dry cloth way
When the fabric is dehydrated and dried, the fabric is dehydrated in the dehydrator with high centrifugal force. When it is too long, it is easy to produce wrinkles that are difficult to eliminate. Many dyeing plants gradually adopt the method of drying the fabric with flat-width water, that is, improve the efficiency of dry cloth. It also helps solve wrinkle problems. After the water is rolled, the cylindrical fabric can be widened by a cloth guide ring and then dried by a shock wave machine. The open fabric can be stretched using a needle chain.
5. Stacking method
The weight of the cloth stacking should not be too large, and the time should not be too long. Especially when the wet cloth is stored, the cloth load per vehicle should not exceed 300 Kg, and the discharge from the cylinder should not exceed 6 hours.
The problem is the result of the entire process. It cannot be solved by the addition of an additive. It is related to fiber, related to the fabric structure, related to the processing technology, and also related to the processing equipment. After the creases appear, it is generally a minor fold. The traces can be fixed by the stereotype machine, and the stubborn cylinders can be washed with water, gradually heated up to 85°C, and then gradually cooled down to 50°C. The process test can be repaired, or steam can be added to the industrial desiccator to retract. Stereotypes, dyeing plants can be repaired according to their equipment and creases.
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