Exploring the technique of color light

2.2 Pioneer pilot production

(1) Do not try to produce without prescription. 

(2) Prior to the mass production of the new color number in the workshop, Pilot Pilot must produce a cylinder in advance. It is absolutely impossible to invest in trial production and put into production (actually it is not put into production directly without trial production), so as to avoid overshadowing, coloring, or dyeing because of shade or color.

(3) Before the trial production and prescription, the color and color of the production sample provided by the proofing house and the original sample provided by the customer shall be carefully checked. If there is any difference, the prescription dosage shall be adjusted beforehand when necessary. To ensure successful pilot production. 

(4) The color light check should pay attention to three points when setting up trial production in the workshop:

1 When the original sample and confirmation sample are all available, the shade of the trial sample should be strictly controlled between the two, and should not exceed the range.

2 There are original samples and no confirmation samples (generally, the samples need not be confirmed by the customer, and the trial production is performed directly), or only when the samples are confirmed without the original samples (usually samples provided by the factory and confirmed by the customer). With the original or approved sample as the standard, the color difference should be controlled at level 4 or higher.

3 Before the cylinder is out of the new color number, a representative color sample should be cut out to imitate the large goods for finishing tests such as soft, waterproof or baking. Because the finishing after dyeing has a considerable effect on the color shade of the fabric. Improper choice of additives (such as soft yellowing agent, etc.) or improper implementation of the process conditions (such as baking temperature is too high, baking time is too long, etc.), the impact of the more obvious shade. Especially in cotton/polyester/polyester/viscose weaving fabrics, when polyester dyes dark and cotton (viscous) dyes light and pale, in the finishing process above 130°C, finishing agents (especially silicone oil softener) may cause dyeing on the surface of the fibers. The disperse dyes in the interior of the polyester fiber migrate to the surface of the polyester fiber in large quantities, causing serious contamination of the cotton fiber or viscose fiber, thereby causing a significant change in color on the fabric surface. If you ignore this point, it will inevitably lead to the result of "the appearance of the cylinder and the deviation of the finished product."

2.3 Cotton brocade or Cotton-cotton-polyester flash-colored weft-elastic cross-fabric (latitude and longitude) has a significant influence on the flashover effect of the cloth surface (even if the color of the latitude and longitude are completely consistent). Therefore, in addition to the stereotyped tenter (which should be wider than the finished width), it must be noted that during the dyeing process, different dyeing equipment (jelly dyeing machines, flow machines) have different effects on the weft and weft density of the fabric. The difference in flash color of the cloth after dyeing is different. Therefore, when staking out the color, in addition to the color depth of the latitude and longitude is consistent with the standard, the sample fabric should be expanded to the finished fabric size to check the overall flash color effect of the fabric. It is important to emphasize here that the overall flash effect of the fabric should prevail, and there are certain differences between the latitude and longitude colors.

2.4 When setting out pilot production to adjust shades, some people like to color the dyes other than prescriptions or even different types of dyes. Such as the reactive dye red M3BE, yellow M 3RE, blue M2GE staining, when the blue-green light is less than the active yellow and reactive blue to adjust, but to the active turquoise blue to color, even with the direct turquoise blue to color This is not allowed. Because such a prescription cannot be used as a criterion for large-scale production; such a cloth, under the prescribed light source, tends to increase the tendency of jumping lights.

2.5 When trial production is in color, if the color of the dyeing sample is too dark, too dark or too red, beyond the allowable range of color toning, it is necessary to use the soda (caustic soda) method, the hydrogen peroxide method or the insurance powder method to handle color reduction and color correction, even if The addition of color is successful, and this kind of sample cannot be used as a criterion for large-scale production. This is because it is difficult to fuse the shades of fabric dyes that have undergone subtractive coloration with the normal color shades of fabrics. Therefore, it is necessary to make appropriate corrections to the dyeing prescription on the basis of trial production of the first cylinder and try another cylinder. Otherwise, after mass production, the color is hardly similar to the first cylinder.
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3 big production

3.1 Sample cloth after trial production must be confirmed and signed by the customer before it can be put into production in batches. Because of the color and color of the trial production samples, it is impossible to reach 5 levels compared with the original sample (or confirmation sample) provided by the customer. There are always some gaps. In actual production, it often happens that the factory believes that the trial production sample is within the customer's requirements, and uses this as a standard batch production. The final customer thinks that there is still a gap between shade, color, and requirements, and rejects the goods, resulting in mass rework. Rehabilitation.

3.2 Samples that have been confirmed and signed by the customer shall be affixed to the customer's original sample and confirmed samples. After a large production, the cylinder sample should be strictly controlled between the pilot production sample and the original sample. It should be noted that after every large cylinder production cylinder sample, must rely on the first cylinder test sample, avoid the second cylinder by The practice of the first cylinder and the third cylinder is based on the second cylinder so as to avoid "coloring out" of color light due to cumulative error. It should also be pointed out that the eyes of the coloring crew must be uniform. Unifying vision is the key to reducing cylinder differences and stabilizing shades. For this reason, it is necessary to carry out uniform training on a regular or irregular basis.

3.3 The old color number produced has to be put into production one week later. Pilot must produce one cylinder in advance and must not be put into batch production. Because after a period of time, often due to the semi-finished or dye differences, resulting in shade changes.

3.4 Dyeing prescriptions for flat cylinders and fluid flow cylinders are not universal. To change the dyeing method, trial production must be re-proofed. Production practices have shown that dyeing prescriptions are used in tandem with one another, which inevitably leads to failure of dyeing.

3.5 For the same color number on the same color sheet, it is necessary to set the tank to production. Because of different operators, the operation methods are different. Even if the same dyeing equipment is used, there are differences in the dyeing results. Therefore, the same color number, only the fixed-cylinder production, can obtain the most stable dyeing effect.

3.6 The same color number in the same color sheet must be processed in the same process and dyed in the same process. If the process is changed halfway, it must cause deviation of the dyeing result and affect the stability of the finished shade. Therefore, when the current treatment process or dyeing process must be changed, Pioneer tests must be done.

3.7 The grey fabrics of different manufacturers do not have the same dyeing results even if the specifications are the same. It is mainly due to the different physical and chemical properties of the fiber components. Especially for cotton/cotton fabrics or nylon/cotton fabrics, the difference in dyeing results is greater when the nylon silk grades, batch numbers, and even varieties (nylon 6, nylon 66) used are different. Therefore, the same color number in the same color sheet must be produced with the same fabric number of the same textile mill. Never change the gray cloth in the middle. If it is necessary to replace it, be sure to do pioneer testing.

3.8 Color cloth dyeing is a common thing in dyeing factories. Whether it is dyeing directly with dyeing or dyeing after color reduction or stripping, trial production must be re-proofed. Absolutely it is not possible to directly change the color (including changing the color). Because of this, it is difficult to meet the customer's export requirements. .

3.9 Before dyeing and feeding, it is necessary to cut a piece of semi-finished product to be dyed first, and compare it with the semi-finished product for proofing (especially the dyeing of pale or bright color or bright color). If it is found that the fabric to be dyed is too yellow or too dark, the production prescription must be adjusted in advance. When necessary, even re-bleaching remediation must not be carried out blindly.

3.10 When coloring after coloring, the sample cloth must be representative.

The production practice shows that within 1m of the tip of the cloth, it usually contains more impurities and the quality of semi-finished products is poor. Therefore, the shade and depth of the dyeing are generally not representative. Pre-stained hair products, with 1m or less on both sides of the joints between the heads, have poor sanding effect, the depth of dyeing is generally significantly shallower, and the shading is not normal. (The thicker and denser the fabrics, the deeper the color is, and vice versa. shallow). Therefore, when color-cutting samples, it is necessary to cut samples other than 1m on both sides of the sewing head, no matter whether it is a sanding product or other product. Other products, generally can be trimmed in two small samples of color; sanding products, you must cut the left and right 3 sample color. Abrasive cloths often have differences in the degree of buffing between batches and batches, between head and tail, especially between the left, right, and right. If you cut a piece of color from the cloth, you will often be misled by the lack of representativeness. 

If two-pipe or four-pipe spray machines are used for dyeing, there will always be some differences in the actual production due to the amount of cloth to be fed, the level of the dye liquor, and the speed of operation. Therefore, there is more or less "pipe difference" (shade or shade) between pipes and pipes. Therefore, after the dyeing, each tube should be cut at the same time, if the difference is obvious, we must take the necessary remedial measures.

3.11 When coloring after dyeing, if the color shade or depth is within the allowable range of color toning, it should be adjusted according to the color standard (including direct feed adjustment and feed adjustment after simple color reduction); if shaded or shaded exceeds the color adjustment allowable Range, it is necessary to timely re-proof the cylinder (need to subtract color or stripping, to handle after the cylinder). Can not blindly adjust in the tank, otherwise, even if the shade is adjusted in place, it will be too long in the cylinder, resulting in degradation of quality.

The practice of 3.12 dyeing shows that the consistency of the dye quality and the accuracy of the measurement are the basic guarantees of stable dye shade. For this purpose, first, a set of standard samples should be established for commonly used dyes. Usually, a wax seal is used to protect it from moisture. When new dyes enter the factory, parallel dyeing tests must be done with standard samples. Only qualified shaders can be used. Avoid using standard products or use them without comparative tests. Second, the measurement must be accurate, we must use electronic weighing. Less than 1kg, use a 0.2g electronic scale, if you dye a particularly light color, if necessary, preparation of dyeing liquid. Less than 5 kg, the use of electronic scale weighing 2g or less, the old pallet scale can not be used. This is very important for stabilizing shades.

3.13 After dyeing cloth drying, can not be directly after finishing, such as soft finishing, waterproof finishing, etc., we must add a semi-finished product inspection, mainly check the quality of the cloth surface is qualified, in particular, shade, depth is within the allowable range of standard samples. Qualified people can only perform finishing afterwards. Otherwise, they will cause troubles for rework and rehabilitate, and even cause no restoration or alteration.

3.14 Common finishing aids, such as softeners, water repellents, anti-ultraviolet agents, antibacterial agents, etc., their own degree of yellowing after heating, chemical interaction between cationic and anionic dyes, conjunctiva on the surface of fibers, and Changes in the light absorption of the fabric, as well as the influence of its own pH on the color of the dye, will change the color of the dyed fabric to varying degrees. Therefore, it is necessary to carefully choose additives, once the brand is identified, should not be replaced frequently, so as not to affect the stability of colored cloth color.

3.15 Washing after dyeing is critical to the stability of dyed shades.

(1) Dyes attached to the surface of fibers (including dye stains on different fibers) are sensitive to heat, light, and post-finishing chemicals, the acidity and alkalinity of the environment, and temperature, humidity, etc., and are susceptible to changes in shade.

(2) The fabric is not clear, with acidity or alkalinity, it will also have a significant effect on the dyeing of fabric dyes. 
If it is dyed with reactive dyes, the water is not clear after dyeing, or the fabric is acid and alkaline, and drying under high temperature and high humidity conditions, especially the contact drying of drying cylinders, will significantly aggravate the hydrolysis of dyes, thus making dyes Severe migration occurs on the fiber surface. This will not only change the color of fabric, but also cause a serious decrease in the degree of cleanliness and color fastness of the fabric. 

In the case of cotton/cotton fabrics or cotton/polyester fabrics, when the nylon or polyester fibers are dyed dark with disperse dyes, if the water is not clear after dyeing, there will be more floating colors and stains on the fibers. Once organic solvent is encountered (washing of oil stains) Such as alcohol, acetone, benzene, DMF, carbon tetrachloride, etc., will occur extraction. That is, the organic solvent dissolves the floating color and stain on the fiber, and after the organic solvent volatilizes, it forms a stain and a color circle on the cloth. Even when doing dry cleaning in organic solvent gas, a significant change in color shade can occur.