This article systematically elaborates on the accuracy and stability of the color and light symbols of the process. It analyzes the factors that affect the color and light from three aspects: making small samples, enlarging samples, and mass production, and puts forward operational precautions based on practice. How to improve the accuracy and stability of the color light of dyed fabrics and adapt to customer requirements is not only related to the economic benefits of the company, but also related to the company’s reputation.
The accuracy and stability of the color light are the soul of dyeing in a dyeing factory.
1. Color proofing
The new color list issued by the business planning department must first be carefully reviewed, including: : The standard samples should be complete, the light source should be clear, the fabric structure specifications should be clear, the dyeing fastness requirements (soaping, rubbing, sunlight, chlorine resistance, dry cleaning, etc.) and post-finishing requirements (soft, waterproof, antibacterial, flame retardant, anti- Ultraviolet rays, etc.) must be accurate, and the sample delivery time must be reasonable. If any problems are found, they must be understood with the business planning department in a timely manner.
Before proofing, the quality of semi-finished products must be determined with the production planning department, such as mercerized cloth or unmercerized cloth, brushed cloth or unsanded cloth, original white cloth or bleached cloth, pre-set cloth or post-set cloth, pre-shrunk cloth Or non-shrunk cloth, etc. The principle is: the cloth used for proofing must be consistent with the cloth used for mass production in the future to unify the process flow and process conditions. Once determined, it should not be changed on the way.
Before proofing, first identify the production method with the production planning department, such as whether it will be liquid jet dyeing or flat vat jig dyeing for large-scale production. Once determined, it should not be changed during the process. Because the proofing conditions of liquid flow dyeing and jig dyeing are different, the dyes and auxiliaries used are also different; if they are changed, the proofing can only be done again, and the proofing prescriptions must not be used interchangeably.
Carefully select dyes based on the customer’s color list requirements for dyeing depth, color brightness and color fastness. For example, if you want to dye a deep color, use dyes with high strength, high darkening properties, and high wet rubbing fastness; if you want to dye light colors, use dyes with high leveling properties and high light fastness; if they are fast to chlorine bleaching, If the fastness to dry cleaning is required, chlorine-resistant dyes should be used; if dry cleaning fastness is required, dyes that are resistant to organic solvents should be used; when dyeing cotton nylon or cotton-polyester interwoven fabrics, especially when dyeing flash white or flash colors, it is necessary to Choose dyes that are less likely to contaminate each other. If it is nylon-cotton or cotton-nylon elastic fabric, when dyeing nylon, disperse dyes and neutral dyes or acid dyes must be well matched to ensure brightness, color fastness and surface uniformity to meet customer requirements. What should be pointed out here is that nylon and spandex have very different color absorption properties (shades and shades) of disperse dyes. Dying nylon with disperse dyes alone has good level dyeing properties, but spandex often appears “different colors” on the cloth surface. The silk “jumps out”, affecting the uniformity and color of the cloth surface.
Before printing the approval sample, the original sample provided by the customer must be re-certified. The original samples provided by customers usually have the following situations:
(1) The tissue specifications of the original samples are different from those specified in the color list. In this case, it is often difficult to match the color of the sample with the original sample due to the different light absorption, reflection and light transmission of the fabric. At this time, you should make a few more samples with different shades and colors for customers to choose from, so as to increase customer recognition rate.
(2) The original sample is not fabric, but printed cardboard. In this case, due to factors such as the smooth surface of the paper pattern, strong gloss, and the fact that the paper pattern is printed with printing paint instead of dye, the color of the dyed sample is generally difficult to match the original sample under the prescribed light source. At this time, we can only print a few more samples with different shades and colors for customers to choose from.
(3) When dyeing cotton-nylon or cotton-polyester interwoven fabrics, if the color depth and color uniformity of the bicomponent fiber in the original sample provided by the customer are poor, there is a two-color phenomenon; at this time, there are usually two This situation: the first is to retain this two-color effect; the second is not to have a two-color effect, but to uniform one color. Therefore, the shades of bicomponent fibers should be evened out (in the original sample, the shades of bicomponent fibers were different, which was due to poor dyeing uniformity). In this case, be sure to ask the customer clearly to avoid the sample not being confirmed.
(4) The original sample has a certain fluorescence under the light source. In this case, be extra careful. There are generally two possibilities: first, the fabric is required to have a fluorescent effect under a specific light source; second, the fabric itself is not required to be fluorescent, but during dyeing, in order to enhance the brightness, a fluorescent whitening agent is added. At this time, the customer’s true requirements must be clarified first, and then samples can be produced according to the requirements.
(5) The original sample is made of silk fabric or acrylic fabric (or acrylic yarn), but the small sample needs to be made of pure cotton, or cotton polyester or cotton nylon. This situation often occurs because the original sample is made of Dyeing with acidic dyes or cationic dyes has very good brightness, so the sample cannot meet the brightness requirements of the original sample. In this case, a similar sample must be made first for customer reference, and the reason must be explained to the customer. If fluorescent whitening agents are added for brightening, the customer’s consent must be obtained.
(6) Customers’ color lists often include “white” color numbers. For example: natural white, ivory white, pearl white, etc., but there is no physical standard sample. In this case, you need to clarify in advance whether the so-called “color light” in the color list refers to original white, bleaching or whitening. If the customer is confused about this and it is difficult to identify it, three samples of original whitening, bleaching and whitening must be taken first to give the customer approval. If it is identified as a whitening sample, yellow light, red light and blue light are generally required.�� method (flat vat dyeing or liquid vat dyeing);
(3) The dye must be selected according to the quality requirements of the customer’s color list;
(4) The dye must be specified by the customer The light source matches the color of the light;
(5) Proofing must be based on the original sample (or first confirmation sample) recognized by the customer.
Under normal circumstances, the color depth of the sample should be controlled within 5%, and the color light should be controlled above level 4. If the texture of the original sample is seriously different from the approved sample, the color and luster can only be matched as best as possible.
(6) The approved sample selected by the customer must be pasted together with the original sample provided by the customer as a basis for color matching for duplicate samples, lofting, and mass production. It should also be noted that the original samples and confirmation samples provided by the customer must be signed by the customer. Because in actual production, it often happens that customers change the standard sample midway, or use another standard sample to accept the large goods, and then deny the original sample previously provided, thus causing disputes about the color and light of the large goods.
2. Setting out for trial production
Replica sample
Before setting out for trial production, you must press Please copy the approved prescription carefully. The following points must be paid attention to when making duplicate samples:
(1) The duplicate samples must use semi-finished fabrics prepared for trial production in the workshop;
(2) Check carefully Duplicate semi-finished fabrics provided by the workshop. For example, whether there is the influence of fluorescent whitening agents; whether the sanding effect and bleaching whiteness are normal. If problems are found, contact the workshop in time and do not blindly copy samples to avoid trial production failure;
(3) Duplicate samples must use the dyeing materials currently used in the workshop. Although the dyeing materials in the proofing room are changed once a week, there are always certain differences in strength, color, moisture content, etc. objectively. This will directly affect the accuracy of setting out;
(4) The copying work must be done by a dedicated person, and it is necessary to arrange for copying by masters who are experienced in proofing and have good sample accuracy. The person who originally made the approved sample should not arrange for duplicate samples. Practice has shown that it is easy to find problems when replacing people and repeating samples, such as inconsistent sampling methods, improper dye compatibility, incorrect use of additives, and improper sampling operations. Problems must be corrected in a timely manner when problems are discovered, and strict precautions must be taken to avoid repeating mistakes or making the same mistake again and again.
(5) The duplicate sample should try its best to match the color, luster and light of the original sample (or approved sample) identified by the customer. If it is a woven or blended fabric, the color of different fiber components must also have good uniformity, otherwise it is not allowed to be put out for trial production.
(6) A review system must be implemented for duplicate samples, that is, the duplicate sample prescriptions prepared for trial production must be reviewed and signed by others to eliminate errors and ensure the last step.
(7) After copying the sample, in addition to affixing the “replica sample” on the production prescription card, a semi-finished cloth sample for the copy sample must also be affixed for setting out. Before dyeing, personnel check whether the quality of the control semi-finished products to be dyed is consistent with the semi-finished products used for duplicate samples to ensure the stability of the lofted color light. </p
