How to control the dyeing and finishing process of colored fabrics
The colored fabric has unique style and Higher added value. Due to its long production process and complicated technology, inaccuracies in sample alignment often occur in actual production, or color changes in subsequent processes cannot be considered, resulting in finished products that deviate from the specified color and cannot even be remedied. Colored yarn matching is not like color matching of colored fabrics in the printing and dyeing industry. The fundamental difference between yarn-dyed and white weaving is that the former is dyed first and then weaved, while the latter is weaved first and then dyed. The color change after first dyeing and then weaving is particularly complicated. It is closely related to the fabric structure, weaving machine process, finishing process and color matching pattern. For example, the relationship between the color finish and the fabric structure is that the warp and weft densities are different from the original, and the color finish is also different, especially the different warp and weft varieties. The color finish difference is even greater; the weaving machine process also has a great influence on the color finish. Large, the obvious difference is the color difference between the small sample and the large sample, because the small sample has small warp tension and large weft tension, while the cloth machine during large-scale production has large warp tension and small weft tension; in addition, the and position lines are also Relevantly, the color of the same variety woven with a high back beam and a low back beam will be completely different. Regarding the post-finishing process, there is a big difference in color between silk-finished and non-silk-finished products of the same variety. Generally, the color after silk-finishing is darker and redder; it is related to the post-finishing setting temperature. The higher the setting temperature, the better the color finish. Redder and darker; it is also related to the color matching pattern. For example, if the customer requires to change the fabric structure or warp and weft density of the sample, the color finish cannot be compared with the original spinning yarn. If necessary, a pioneer sample must be made to adjust the color finish. . Therefore, to understand the color finish, one must understand the fabric structure design, weaving machine process, post-finishing and color matching patterns, etc., and cannot just stop at aligning the color finish in the dyeing workshop.
1 The impact of sample management on coloring quality
In the yarn-dyed production process, yarn dyeing is the first step and an important link, and modern management should be adopted. First of all, from the perspective of the proofing procedure, the current common management status is that when a piece of sample is received, the proofer is first assigned to proofing, and then the proofer’s prescription and yarn sample are submitted to the process supervisor for confirmation. This traditional model can no longer adapt to the modern governance system. The correct method should be to collect all the process recipes that have passed several times of stakeout (that is, the recipes that have been successfully staked out once), and divide them into several series according to different colors (such as red, yellow, blue) and different dye production units. , each series is divided into a number of serial numbers, these prescriptions are stored in the computer, and a certain color can be found through the code search of the colored yarn. At the same time, all the yarn samples of these prescriptions are included in the sample and compiled into a chromatogram. The advantages of adopting this governance approach are:
(1) The prescriptions that pass several times of placement and are successful once are all relatively successful prescriptions, especially their compatibility, various physical indicators and operability are more suitable for production.
(2) From a management perspective, computer processing is more convenient for centralized management.
(3) Save labor and improve efficiency. There are many similarities between one piece of fabric and another piece of fabric, and one color and another color. They can also be similar colors or sister colors, but assigning them to several people for proofing is a waste of time and labor, and affects The first-time success rate of staking.
(4) Various dyes can be divided into dark, medium and light colors according to the amount of materials used. This can not only strengthen the economic accounting assessment of internal management, but also provide certain reference materials for future external arrangements. .
(5) Supervision and manipulation can be strengthened. For example, the assessment of the first-time success rate, the assessment of the consumption of dyes, etc.
2 The impact of the formulation process on the coloring quality
2.1 Auxiliary dosage
In order to reduce the error between proofing and dyeing in the vat, it is absolutely required that the coloring in the vat be consistent with the coloring in the vat during the proofing process, that is, it is required to add the same additives as the bulk products in the dye bath. Auxiliaries and their dosage are as follows:
Glacial acetic acid 1g/L
(i.e. dissolve 1g/L to 100mL and draw 5mL)
Diffusion agent NND1.5g/L
Leveling agent 10111.5g/L
Dispersing chelating agent ARSK0.3kg/L
Leveling agent CE 4001g/L
Penetrating agent JFC 0.5g/L
Make ARSK, CE 400, and JFC to a concentration of 10%. Immediately reduce the original solution from 100mL to 1000mL for later use. If the total sample volume is calculated as 50mL, you need to add 10% concentration of ARSK 0.15mL, CE
4000.5mL, JFC0.25mL.
2.2 Standardize the coloring process
(1) Disperse dyesThe number should be as low as possible.
(1) Use CF type dyes to dye medium and light colors. Use red, yellow, and blue to match colors. Do not use navy blue CF B to match colors. When dyeing dark colors, use red, yellow, and navy blue to match colors. .
(2) Use Kehuasu dye for coloring. Generally, navy blue BF is used for light and medium colors, and navy blue BI33 is used as the main color for dark colors. Green does not need to use emerald blue ED G. And use Navy Blue 2G.
(3) Use Shanghai Wonder B-type dye for coloring. Its red B 6BF is not suitable for package coloring. It is better to use Yagesu Red BF DB200% instead.
(4) Use disperse dyes for coloring. The light-colored varieties use low-temperature type 3B red 3B, yellow SE 5R, and blue 2BLN as the three primary colors; the medium-dark varieties use high-temperature type ruby S.
5BL, orange S 4RL, dark blue HGL are three primary colors; Yuan H3BL is a high-temperature mixed dye, and it is not suitable to use low-temperature three-primary color combinations; dark blue, dark green and dark yellow-brown varieties are best to use high-temperature dyes to improve dyeing fastness .
3.3 Additive quality
There are many kinds of auxiliaries. If used improperly, the color of the dye on the yarn will be different, resulting in inaccurate and unstable color. For example, when using Disperse Blue 2BLN and Disperse Yellow SE 5R to dye green, the Disperse Yellow SE
5R is more sensitive to pH value. If there is a quality problem with glacial acetic acid in the dye bath, or the content is insufficient, causing the pH value to be too high, the color will be less yellowish and bluish after coloring. Other auxiliaries, such as leveling agents, chelating agents, penetrants and fixing agents, also have batch differences in concentration and impurity levels. Therefore, each batch of incoming goods is required to be tested, and a dye and chemical material file for the website system is established.
3.4 Auxiliary dosage
In order to standardize operations and ensure color stability, the dosage of Yuanming powder and soda ash is specified according to the different properties of various dyes (Tables 1 to 5)
4 The impact of post-finishing process on coloring quality
Post-finishing process: seam turning → singeing → desizing → silk finishing → drying → shaping → shrink prevention → code inspection
4.1 The impact of silk finishing on coloring quality
4.1.1 Strictly control the finishing speed
The finishing speed of the yarn-dyed combed poplin silk is 45~50m/min. It has been measured that it takes 50 seconds from the alkali rolling tank to the alkali washing place, which is conducive to the penetration of cotton fibers and plays a better role. Good silk works well.
4.1.2 Select the appropriate alkali concentration
Theoretically speaking, 130g/L alkali concentration can produce perfect silk luster. As the alkali concentration increases, the perfect luster will also increase accordingly; when the alkali concentration exceeds 300g/L, the perfect luster will On the contrary, it has declined. Comprehensive consideration, the general yarn-dyed natural color cotton fabric and alkali concentration settings are shown in Table 6
4.2 Effect of shaping on color quality
4.2.1 Strictly control the setting temperature and vehicle speed
The setting temperature of products such as yarn-dyed poplin is generally controlled at 170℃~185℃, and the vehicle speed is about 40m/min, which will not affect the coloring quality.
4.2.2 Master color correction skills
Some slight color differences in batches can be solved by shaping. If the whiteness is not enough, you can add polyester whitening agent or cotton plus whitening agent in the rolling water tank; you can also add dispersed blue and purple to Improve whiteness.
5 Conclusion
In short, there are many factors causing inaccurate placement and batch color differences, which vary due to different production conditions of each factory. After taking the above measures, the yarn-dyed fabrics produced by our factory can meet the production characteristics of small batches, multiple varieties, and strict color differences. The lofting pass rate and first-time success rate have been significantly improved, the production cycle has been shortened, and the cost has been saved. Finished products and foreign trade The color differences of the samples are all above level 4.
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