Abstract
Introduced the classification and causes of common defects in dyeing and finishing production, and analyzed color unevenness one by one from the aspects of color quality, intrinsic quality and other quality aspects. (color flowers, color spots, color stains), color fastness, fiber damage, loss of elasticity, longitude and weft skew, dense road, shrinkage, gram weight and width size, as well as finishing stains, pilling, and crepe Reasons and solutions for dyeing and finishing defects such as printing crepe strips and substandard finishing.
In summary:
Spinning and weaving should be strictly controlled process to avoid dyeing and finishing defects caused by different yarn batch numbers; at the same time, suitable dyes, dyeing and finishing auxiliaries and dyeing equipment should be selected for different fibers and different textile varieties, and appropriate processes and Reduce the number of repairs and avoid the occurrence of contamination defects.
In the dyeing and finishing production of textiles, due to the many front and back links, there are many factors that affect the dyeing and finishing results. In addition to the more frequent color and luster quality defects such as color difference, outside. There are also other quality issues that often arise. Dyeing and cosmetic blemishes can be basically divided into the following three categories according to their phenomena:
a. In terms of color quality: color difference, uneven color (color flowers, color spots, color stains) and color fastness.
b. In terms of internal quality: fiber damage, loss of elasticity, skewed longitude and latitude, sparse paths, shrinkage, gram weight and door width, etc.
c. Other quality aspects: Finishing agent stains, fluffing and pilling, crepe printing and substandard finishing, etc.
1. Causes of dyeing and finishing defects
1.1 Yarn ( The quality of yarn (silk) and gray cloth
The quality of yarn (silk) and gray cloth affects the quality of dyed finished products. This influence has a certain latent nature and is often exposed after dyeing. come out.
And this impact is often overlapped with problems that arise during the dyeing and finishing processes, increasing the complexity of dyeing and finishing defects. It also makes it more difficult to find the causes of defects. Some dyeing and finishing defects caused by yarn (silk) and gray fabric quality problems, such as width size, warp and weft skew, and expansion rate, etc., although they can be slightly adjusted in the finishing process, they cannot Solve the problem fundamentally. Therefore, the source of raw materials should be strictly controlled to ensure that the quality of yarn (silk) and gray cloth reaches the target to avoid the occurrence of defects in subsequent dyeing and finishing processes.
1.2 Dyeing and finishing process
The quality of the dyeing and finishing process is affected by Impact on both hardware and software.
Hardware: The first is the suitability and integrity of hardware such as mechanical equipment and instruments; the second is the inspection and selection of the quality of raw materials such as dyes and auxiliaries.
Software: Mainly reflected in the implementation selection of process prescriptions, production processes, operating procedures, etc.; also reflected in the management level (including technical management, discipline management) and grassroots The overall quality of employees. First of all, we must have a clear understanding of the variety adaptability of dyeing and finishing equipment, because dyeing and finishing machinery is differentiated and specific for different fibers and different types of textiles. It is necessary to understand the fibers that dyeing and finishing machinery can add and its adaptability to woven fabrics. Or knitted fabrics, if it is suitable for knitted fabrics. It is also necessary to distinguish whether it is suitable for warp knitted fabrics, weft knitted fabrics or horizontal knitted fabrics; it should also be understood whether the equipment is limited to a single variety, or a composite type that can be used for several categories of varieties.
For example:
A. The high-speed and high-pressure jet dyeing machine is suitable for dyeing polyester warp knitted fabrics, and is also suitable for dyeing polyester processed filament medium-thick wool-like style woven gray fabrics; however, it is not suitable for polyester filament low-density thin woven fabrics (such as It is also not suitable for the dyeing of polyester viscose, polyester-cotton and other blended fiber fabrics and weft knitted fabrics. Otherwise, it is easy for cracks and seams to appear after dyeing (filament low-density thin woven fabrics) or pilling (polyester-viscose, polyester-cotton blended fiber fabrics) or the fabric’s original elastic characteristics will be lost (weft-knitted fabrics). ).
B. The jigger dyeing machine is suitable for dyeing small batches and multiple varieties of woven fabrics with a wide range of light weight and thickness. But it cannot be used for knitted fabrics with loop structure.
C. The overflow dyeing machine is suitable for weft knitted fabrics, polyester-viscose, polyester-cotton blended fibers and knitted fabrics with high elastic requirements, but it is not suitable for dyeing warp knitted and woven fabrics. Silk woven fabrics should be dyed on jig dyeing machines, but crepe fabrics and silk knitted fabrics, which are both woven from silk, should be dyed on specially designed machines that are significantly different from the overflow dyeing machine used for cotton. Secondly, different dyes are suitable for different fibers, and are suitable for different deep, medium and light colors. Therefore, it is necessary to distinguish between different types of dyes, such as S-type disperse dyes, which are suitable for dyeing with deep and intense colors. E-type dyes are suitable for medium and light color dyeing; BES type among B-type reactive dyes are suitable for medium and light color dyeing, and B-D types are suitable for deep and dense color dyeing. Due to the differences in fiber and fabric varieties, dyes, and dyeing and finishing machinery and equipment discussed above, the selected additives will also be different.
For example:
Semi-filled jet dyeing machines, liquid flow dyeing machines, etc. need to use defoaming agents; while fully-filled Jet dyeing machines, non-nozzle overflow dyeing machines, jigger dyeing machines, rope dyeing machines, etc. do not require defoaming agents. Another example is silicone oil softeners, which are widely used in fabrics and clothing.� is not obvious, so it is easy to be ignored. Although dyes with good hiding properties will be screened during dyeing to control such problems to a certain extent, they cannot fundamentally solve the problem. Generally speaking, gray fabrics with such problems are best arranged to be produced in white. , followed by the production of black or printed fabrics. Dense road refers to the phenomenon that after the fabric is dyed, the cloth surface presents optical illusion properties.
Similarly, sparse and dense road problems are not easily discovered when the blank is blank and are often ignored. The occurrence of sparse paths is due to the loosening of the knitting needle position after the knitting machine has been used for a long time. Irregularities in the arrangement; woven fabrics may be caused by the abnormal beat-up device of the loom. These problems are generally caused by the lack of technical quality of the loom maintenance workers and the lack of strong sense of management responsibility.
Therefore, it is necessary to improve the quality level of grassroots employees and strengthen the supervision of managers to avoid the occurrence of such defects.
4. Analysis of other quality defects
4.1 Compilation There are many types of post-finishing stains
They are as important and influential to textiles as the finishing process after dyeing. Defects in finishing will inevitably occur in process design. In order to shorten the production process and save time, softness, antistatic, waterproof and oil-proof finishing are often carried out together. However, due to the compatibility issues of various additive varieties, it is more likely to cause defects such as spots and stains on the finishing agent. And some finishing defects are irreparable for textiles with multiple colors of yarn and cloth, such as the use of silicone oil softeners to dye loose fibers of cotton fibers, single yarn bobbins and skeins. Finishing is often carried out in dyeing machines. After continuous use for a long time, such softeners will accumulate on the inner walls of the processing equipment and its pipes. After a certain level, the accumulation may suddenly fall onto the fibers, causing silicone oil stains, and fiber silicone oil The removal of stains is very difficult; in addition, people require the effects of finishing aids to be durable. But the better the durability, the more difficult it will be to repair and remove. For example, silicone softeners, fluorine-based three-proof finishing agents, coating agents, etc. are all types with excellent durability and difficult to remove. Therefore, when using such reagents, repairs should be avoided as much as possible, and the use process should be meticulous and standardized.
4.2 Pilling
Fuzzing and pilling are not mercerized. Woolen polyester-cotton blended fabrics, polyester-viscose blended fabrics, and polyester-nitrile blended fabrics are prone to occur. As mentioned in 1.2, improper selection of dyeing machines is one of the causes of such dyeing and finishing defects.
4.3 Crepe printed crepe strips
Large-area crepe printing is loose One of the problems caused by the dip dyeing method is mainly caused by the dyeing mode of the dyeing machine and its equipment characteristics. Anti-wrinkle additives are beneficial to avoid the appearance of wrinkles in liquid jet dyeing machines. The difference in the shrinkage rate of the fabric in boiling water in the dyeing bath caused by the yarn and fabric structure of the gray fabric will also cause the appearance of wrinkle marks and straight wrinkle strips. This is mainly due to the lack of control and prevention in the tight open-width dyeing equipment system. Therefore, the process should be strictly controlled.
4.4 Finishing is not up to standard
Functional finishing such as softness , waterproof and anti-static, etc., if the functional indicators are not reached, the finishing should be carried out again. However, the functional index saturation point of some finishing additives should be experimentally identified, otherwise repeated finishing will have little effect.
Conclusion:
The factors that affect the quality of dyeing and finishing are relatively There are many factors, including fiber, gray cloth, dyes and auxiliaries, as well as the matching of textile varieties and equipment; it also includes factors such as technology, technology, management and the quality of grassroots employees.
Therefore, repairs in dyeing and finishing production cannot be completely avoided; repairs are also an indispensable technology in dyeing and finishing production. However, some defects cannot be repaired once they occur. Repair and return to normal. Especially some hard damages such as fiber brittleness, holes, fabric tissue cracks and seams, pilling, etc.; in addition, certain textile types such as multi-color yarn, multi-color yarn, yarn-dyed and printed varieties. ． For non-damage defects that can be repaired by stripping and re-dying, such as finishing agent stains, discoloration, color matching, staining, etc., it is also not suitable for repairing certain textile and weaving defects; Such as excessively serious warps, rungs, dense roads, gram weight and door width, etc.
It is generally difficult to make fundamental corrections during the dyeing and finishing process. Therefore, a comprehensive prevention-oriented strategy should be adopted in a timely manner wherever problems may occur during the production process. Only in this way can we proactively and truly effectively reduce and avoid quality problems in dyeing and finishing production. </p
