Look at the impact of textile quality on printed and dyed products from the perspective of printing and dyeing processing, and discuss some practical problems encountered by surrounding printing and dyeing enterprises in production practice. It aims to strengthen the links between upstream and downstream enterprises and improve the quality of textile final products. The interdependence of product quality between upstream and downstream textile enterprises is becoming more and more important, which requires close collaboration between upstream and downstream textile enterprises in fiber raw materials, spinning, weaving, post-printing and dyeing processing, and clothing. Based on the practice in printing and dyeing enterprises for many years, below we only discuss the impact of textile quality on subsequent printing and dyeing processing from the perspective of printing and dyeing processing, so that colleagues can pay attention to it.
1 Influence of yarns
1. Low-grade cotton
After low-quality cotton is mixed into the yarn for weaving, dyeing defects will occur during the printing and dyeing process, especially when mixed into high-count yarn, which will reduce the quality of the product after being woven into high-end products. grade. Cloth woven from this kind of yarn can be used as sanded or velvet products, and dyeing it in a light color can barely cover it up, but the product grade will not be very high. Dying it in a dark color will affect the color and brightness. Even when making corduroy products, the fullness and natural luster of the down will be affected. Especially if fabrics with different cotton grades are not marked with the same dyeing color, it will cause serious matching differences and mislead technicians to adjust the shade.
2. Dead cotton
Dead cotton is an immature Cotton, even after pre-treatment, is still resistant to dyes and produces white spots on the cloth surface. Dying with light colors can weaken or eliminate their effects. Once dyed with medium to dark colors, these white spots will generally not be accepted by customers. Corduroy products can be reduced by heavy brushing at the front and back, but serious ones cannot be eliminated without improving the bottom board. They can basically be solved by washing with an industrial water washing machine. The appearance of velvet fabrics and plain cloth that do not need to be washed will seriously affect the appearance.
3. Three silk threads
3.1 Snakeskin silk:
It is mainly mixed in during the process of packaging and mixing cotton. It is best to sort it out before spinning. After weaving, it needs to be repaired and sorted out, and it is left after it is sent to the printing and dyeing factory. It’s very troublesome. You can use contact singeing machine and high-temperature baking method to further remove some of the tiny snakeskin silk. It often needs to be repaired after dyeing. If you use high-temperature method, it will often cause discoloration, and it cannot be used on spandex elastic fabrics. High temperature can only rely on manual weaving methods. This method will also leave many small defects on the cloth, which greatly affects the quality of the product.
3.2 Special-shaped yarn:
Printing and dyeing factories are accustomed to one list First shallow and then deep. If special-shaped silk is mixed in, it will be difficult for the human eye to distinguish due to the strong whitening and stone color coverage. Therefore, by the time it is dyed in a dark color, more than half of the problem will be revealed. At this time, the delivery time of the gray fabric has already been adjusted. Being caught off guard can sometimes cause huge losses to the printing and dyeing process.
3.3 Colored yarn:
Has a great impact on medium and light colored products If it is large, it will often cause the entire order to be wiped out. Some colored yarns will be removed before dyeing and finishing. Most of the colored yarns cannot be removed during the printing and dyeing process and can only be repaired manually, so the quality of the cloth is difficult to guarantee.
4. Neps and impurities
Affect end-breaking in air-jet looms The rate and increase of weaving defects will also affect the opening of corduroy fabrics, increase missed cuts and holes, thereby increasing repair marks and repair marks. It will also cause serious small color spots and white spots during dyeing. Nowadays, the improvement of weaving technology requires the utilization rate of cotton yarn grade to increase, and the phenomenon of neps and impurities becomes finer. Common cotton woven fabrics can use contact singeing to remove neps. It is more difficult to process elastic fabrics with spandex filament. Generally, light sanding is used to solve the problem.
5. Oil stained yarn
Made into bleached, light-colored, special For sensitive colors, the oil stains and oily yarn must be washed clean and then sent to the printing and dyeing factory, commonly known as light-colored fabrics. Such gray fabrics should not be made into dark colors, as dark colors will cause repair stains. It is best to choose a degreaser for cleaning oil stains in the weaving factory that can be easily removed during the pre-printing and dyeing process. Therefore, the weaving factory must distinguish dark and light-colored blanks and not mix them up, and the dyeing factory must also distinguish between the dark and light-colored blanks in the production planning and arrangement. Even if the gray fabric with oil stains is washed, it will have no effect on the dyed fabric, and it will still reappear after subsequent finishing such as frost flowers.
6. Warp yarn mixed in
The yarn count is different and the twist is different 1. When warp yarns with different cottons are used, dyeing warp defects are easy to occur. Such as warp stripes, warp yellow and white, etc., elastic fabrics are also prone to defects such as wrinkled strips.
7. Elastic yarn
7.1 Drafting ratio: The drafting ratio should be appropriate, for example, 3 to 4 times for 40D; 3.5 to 4.5 times for 70D. The larger the draft multiple, the better the elasticity. Insufficient draft multiple can easily cause the door width to be over-wide.
7.2 Core-spun yarn is generally used, and the spandex yarn in the twisted yarn is easy to be exposed.
2 The influence of weaving
1. Sizing
1.1 Paraffin: Causes wax filaments and wax spots (well emulsified and dissolved paraffin has less impact) and will cause dye rejection in the back process.
1.2 Silicone oil: The proportion of silicone oil in the slurry is too large, which affects the quality of scouring and bleaching.
1.3 PVA and other chemical pulps: The selection of PVA pulp is not standardized, and some PVA pulps are difficult to remove before printing and dyeing. Affects the feel, coloring and fastness of dyed fabrics.
1.4 Mildew: In rainy seasons, when the air is relatively humid, cotton cloth is susceptible to moisture and mildew. The mildewed cloth will be damaged after printing and dyeing.Damaged fabrics, unless they are very minor, will not be visible on the surface, but the strength will decrease with the degree of mildew. It is best to add some preservatives appropriately when sizing, but if the preservatives are not added properly, if the entire dyeing and finishing process is not handled cleanly, it will also cause environmental problems.
2. Edge organization
The quality of edge organization has great influence on printing and dyeing Processing has a great impact, mainly causing wrinkles, curling, gaps, etc.
2.1 Bad edges and tight edges:
For locking edges The gauze is broken. Tight edges can easily cause gaps during the printing and dyeing process, resulting in wrinkles or even fabric breakage during production.
2.2 Unreasonable preparation of ground tissue and edge tissue
Tightness Improper adjustment causes defects such as curling: especially for stretch fabrics and twill fabrics, it is best to widen the selvedge by 1.5 to 2cm and add appropriate reinforcement ribs. Fabrics with special specifications that are particularly prone to curling can be woven with more than two reinforcing ribs (commonly known as tank edges). The slow and excessive elasticity of the edge tissue can achieve the best anti-rolling effect.
2.3 The structure causes left and right color difference
Such fabrics should be sent to the printing and dyeing factory Frequent adjustments to the left and right color differences due to mixing and turning fabrics on the dyeing line cause serious left and right color differences in the finished product, seriously affecting product quality. This reason may be that the air-flow yarn feeding of the air-jet loom untwists the yarn, causing the yarn twist on the inlet side and the outlet side to be inconsistent, causing different color absorption rates on the two sides, resulting in color difference. It is recommended that weaving mills with such complaints make distinguishing marks on the edges of the cloth. For example, add a piece of colored yarn on the import side. Printing and dyeing factories use the adjustment function of the uniform padding car to solve the problem of edge-turning.
3. Other aspects
3.1 Inconsistent warp tension can easily cause Rain strips and elastic fabrics will cause inconsistent door widths.
3.2 Rusty steel reed on the upper machine can easily cause local sporadic pinholes and small oxidation holes in the printing and dyeing process.
3.3 Due to cost considerations when designing the weight of elastic fabrics, the warp density is added to increase the weight. Sometimes the warp density is too large to affect the weft processing coefficient, causing the door width to exceed Width.
3.4 Edge dye rejection: Because edge tissue is prone to problems, wax is often applied near the edge during weaving to increase slipperiness, which will cause dye rejection defects during low-temperature dyeing. .
3.5 Density grade, yellow and white grade: This reflects the weaving and yarn management level of the weaving factory. After dyeing, obvious dark and light marks are formed, which are more obvious when used in blue, gray, grass green and other colors, and the yellow and brown series are slightly better.
3 Requirements for multi-component fiber fabrics
Blended fabrics The proportion must meet the customer’s requirements. When making the same color, it will not be visible on the surface, but it will be revealed when testing the ingredients. When doing extra dark single dyeing, the color cannot be improved if the content of this component is insufficient. Product design should consider the feasibility of printing and dyeing processing. When superimposing multi-fiber functions, the difficulty of printing and dyeing processing and whether printing and dyeing processing will damage the fiber functionality should be considered. The nylon yarn raw materials used in cotton nylon fabrics must be of the same batch number to avoid inconsistent dyeing shades.
The above situations are limited to common problems encountered by surrounding companies. Since the processing varieties of each printing and dyeing company are different, Production conditions and environments are different, and the requirements for upstream textile companies are also different. This requires upstream and downstream companies to maintain regular communication in order to improve each other and create a win-win situation.
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