In production, we often encounter polyester or polyester-containing fabrics after dyeing. , the color and light are normal but the color and light do not match after the next process of finishing, resulting in discoloration or local spots, strips of color flowers and a decrease in fastness. Such problems are minor and can be repaired through re-repair, but serious ones are Even after repair, it is difficult to meet the requirements, which will have a certain impact and loss on the normal production, delivery time, quality and efficiency of the factory. The following is a brief explanation of its causes and preventive measures for the reference of peers.
Cause analysis
Polyester warp Thermal migration phenomenon after disperse dye dyeing is the key to the above problems. Thermal migration is a ubiquitous property of disperse dyes. It means that part of the dye passes through the fiber under the action of dry heat or hot and humid air during post-finishing and high-temperature setting. Capillaries migrate from the inside of the fiber to the surface of the fiber, causing the accumulation and redistribution of dye on the surface of the fiber. The presence of additives and surfactants, including residues on the cloth, will aggravate the occurrence, because this thermal migration is mainly related to the dye itself. It is related to the structure, and the thermal migration of disperse dyes with different structures are also different, and they are also very different from each other. Therefore, when post-finishing and high-temperature setting, especially when using silicone oil and antistatic, they contain a certain amount of surface Active agents, and when these additives are unevenly adsorbed on the cloth surface, including uneven PH on the cloth surface, a series of problems such as the above-mentioned so-called color flowers, discoloration, and decrease in fastness such as friction, washing, and staining will occur. This phenomenon often manifests itself as one or several coexistences, which brings insurmountable hidden dangers and hazards to the dyeing quality.
Preventive measures
1. First, choose materials with low thermal migration and similar disperse dyes. Because these dyes have larger molecular weight structures and greater affinity with polyester fibers, they are difficult to migrate from the inside of the fiber to the surface. For example, Longsheng’s LXF type, BASF’s XF type, DyStar’s Dainix XF/SF type and Annochi’s MS series all have good thermal migration fastness.
2. When selecting color matching dyes, try to use the same type or high-temperature dyes, because different types of dyes have different thermal migration ratios and different sublimation fastnesses. The sublimation fastness of the type is higher. Although the thermal migration fastness of the dye is not consistent with the sublimation fastness, the high-temperature dye has less sublimation of the dye under higher temperature setting, and the stability of the corresponding color light is also better.
3. The finishing process adopts a gentler process. The darker the color, the more the dye will migrate. The higher the temperature, the greater the impact on migration. In order to ensure the setting effect In this case, a temperature of 150°C or lower can be used depending on the variety. This avoids or reduces dye migration.
4. Choose the finishing softener and try to use emulsifier-free hydrophilic silicone oil or self-emulsifying Block silicone oil, and this type of silicone oil has good stability, low discoloration and yellowing, and can have a good preventive effect on dye migration.
5. Strengthen the restoration and cleaning after dyeing, especially for dark colors. The floating color must be fully cleaned to ensure For its own fastness, try to use acidic cleaning. If you use alkaline insurance powder process, it must be neutralized, because some dyes are more sensitive to PH, and some will turn blue and purple after high-temperature finishing when PH>6. And some of this discoloration is irreversible and cannot even be repaired.
Summary
In short, through the above measures and reasonable pre-treatment and dyeing processes, I believe that a series of quality problems such as color flowers, color changes and decrease in fastness after finishing and styling can be controlled within Within the scope of our requirements. </p
