With the development and application of new textile materials, the variety of textile products is becoming increasingly diverse, and clothing processing enterprises have higher quality requirements for printed and dyed products, mainly manifested in the color consistency of dyed products and the various fastness indicators of dyed products. This puts higher demands on technical personnel engaged in color matching and sampling work.

Requirements for color matching and sample making technicians

Color matching and sampling is a skill, and the speed and accuracy of sampling mainly depend on the accumulation of basic information and experience of color matching and sampling technicians.

As a technical personnel engaged in color matching and sampling work, one should master the basic principles and methods of dye matching, the properties of dyeing and chemical materials, and textiles, especially the color characteristics and basic properties of the dyes used (such as color brightness, strength, color fastness, and enhancement). They should also have sufficient understanding of the three primary color mixing effects of dyes, so as to correctly select dyes, quickly and accurately match, sample, and lay out colors, and put them into production.

For a technical personnel engaged in color matching and proofing work, to accumulate basic information and experience in color matching and proofing, they should start from the following aspects.

1. The production of monochrome sample cards

The purpose of making a monochromatic sample card for dyes is to grasp the color characteristics of the dyes used, including color light, force, lifting force, and the variation of color light with dyeing depth during dyeing. For a beginner, they can use a certain concentration gradient to make a series of monochromatic dyeing samples, and find out the pattern of the color of the dye changing with the depth of dyeing, and master the dyeing performance of the dye used.

The production method of dye monochrome sample cards is shown in Table 1

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2. The production of a tower diagram for the three primary colors of dyes in color matching

The purpose of creating a tower diagram of three primary dye color matching is to master the principles and methods of three primary dye color matching. Technical personnel engaged in color matching and sampling work must master the principles and methods of color matching with three primary dyes.

The mixing of colors is a relatively complex problem, but both follow the principles of additive mixing and subtractive mixing. In practical work, as long as you master the basic principles of color matching and strictly distinguish whether specific color mixing is additive or subtractive, you can improve the efficiency and quality of color matching.

In the color matching and sampling of printing and dyeing enterprises, subtractive color mixing is mostly used. The three primary colors of subtraction mixing are: magenta, yellow, and cyan (usually red, yellow, and blue in practical applications).

Comparison between laboratory sampling and workshop mass production

There is a certain gap between sampling in the laboratory and large-scale production in the workshop, and the existence of these gaps will affect the conformity rate of dyeing samples. Taking immersion dyeing as an example, the dyeing similarities and differences between making small samples and large-scale production are shown in Table 2.

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Factors affecting the matching rate of staining samples

In actual production, there are many factors that affect the conformity rate of large and small samples. Through analysis and research, the main aspects can be summarized as follows.

1. Differences in quality of semi-finished products for bleaching and refining

Whether the quality of semi-finished products used for laboratory sampling is consistent with that of semi-finished products produced in the workshop is crucial for the consistency of the size samples. In actual production, due to factors such as different raw material origins and pre-treatment production processes, the quality of semi-finished products may be inconsistent. In addition, it is difficult to match the fabric used for laboratory sampling with the fabric used for workshop production, which can lead to a decrease in the conformity rate of large and small samples.

Therefore, the selection of semi-finished products in the laboratory should adhere to the principle of frequent collection and exchange. In the actual operation process, in order to avoid the impact of semi-finished products on the conformity rate, it is possible to take a sample of the semi-finished products before producing the bulk goods, and prevent the conformity rate from being affected by differences in the quality of the semi-finished products. There are many related discussions on the issue of dyeing without boundaries.

2. Differences in Dyeing and Chemical Materials

The same dye, products produced by different dye enterprises, and even different batches of dyes produced by the same dye enterprise, have significant differences in color and strength.

3. Differences in dyeing process conditions

The difference in dyeing process conditions is also a key factor affecting the matching rate of large and small samples.

3.1 Dyeing bath ratio

The size of the dyeing bath ratio mainly depends on the equipment used for dyeing. The bath ratio of the dyeing sample machine is generally 1:20-1:30; The bath ratio of the jet overflow dyeing machine is generally 1:8-1:15. From this, it can be seen that there is a significant difference in the bath ratio for staining between large and small samples. Production practice has proven that changes in the dyeing bath ratio can have a corresponding impact on the dyeing results (dyeing depth, color light).

3.2 Dyeing temperature

The temperature difference during the dyeing process is also an important factor affecting the sample matching rate of large and small samples. Taking medium temperature reactive dyes as an example, different dyes have their own optimal fixation temperatures, and they have different fixation rates under different fixation temperature conditions.

In actual production, whether it is a small sample dyeing machine or a production jet overflow dyeing machine, there is generally inaccuracy in temperature measurement and control, resulting in a discrepancy between the displayed temperature on the machine and the actual temperature of the dyeing solution, with a general error of 3.8 ℃. This will seriously affect the sample compliance rate of large and small samples.

3.3 Staining time

As is well known, only by achieving an ideal "dyeing balance" can immersion dyeing overcome or reduce color differences, achieve better dyeing reproducibility, and improve the sample matching rate of large and small samples.

However, in actual production, due to differences in the technical level and quality of dyeing operators, their attitudes towards work are different in terms of seriousness and responsibility. During the operation process, there is a high degree of randomness, which cannot guarantee the dyeing time and affects the sample compliance rate of both large and small samples.

afterword 

Through analysis and research, it has been found that only by achieving the following points can the compliance rate of large and small samples be effectively improved.

1. Regular training should be provided to laboratory color matching and sampling technicians and workshop operators to improve their technical level and quality, enhance their quality awareness, ensure the correct implementation of dyeing processes, and avoid the impact of human factors on the matching rate of large and small samples.

2. Try to ensure that the specifications and quality of semi-finished products used for laboratory sampling are consistent with those used for large-scale production in the workshop, to avoid affecting the sample compliance rate due to differences in semi-finished product quality.

3. Ensure that the performance of the laboratory samples is consistent with that of the dyeing and chemical materials used in the workshop production. The purchased dyeing and chemical materials should be tested to ensure their quality, and the quality of the dyeing and chemical materials should not affect the sample compliance rate of the dyeing and chemical samples.

4. Try to ensure that the process conditions for laboratory sampling are the same or similar to those for workshop production. Regular maintenance and upkeep of equipment should be carried out to avoid errors in process conditions caused by equipment reasons that may affect the sample compliance rate of large and small samples. (Source: Learning and Exchange in Printing and Dyeing, dyeing and finishing without boundaries)