Supreme Cashmere Series Fabrics, representing high-end textile raw materials, relies on a multi-dimensional technological approach to ensure color durability in its dyeing process. From raw material pretreatment to dye selection and finishing processes, each step requires precise control to address the challenge posed by the unique scaly structure of cashmere fibers to dye adsorption.
Raw material pretreatment is fundamental to color durability. The surface of cashmere fibers is covered with a ring-shaped scaly layer. While this structure gives it a soft feel, it also easily leads to uneven dye adsorption. To address this issue, some companies employ a cashmere bleaching process. This involves forming a chelate with the pigment using metal salts (such as copper salts), which is then oxidized and dissolved under the action of hydrogen peroxide, turning the fiber color to light brown. A subsequent alkaline reducing agent treatment restores the white color. This process not only improves the whiteness of the raw material but also enhances subsequent dye adsorption by removing surface impurities. For unbleached raw materials, low-temperature enzymatic treatment or oxidative pre-reduction treatment is used to decompose surface proteins and remove skin-like deposits, allowing the dye liquor to penetrate the fiber more easily.
The choice of dye directly affects color stability. Supreme Cashmere Series Fabrics prioritizes environmentally friendly reactive dyes. The active groups in their molecular structure form covalent bonds with the amino and carboxyl groups of cashmere fibers, achieving a chemical bond between the dye and the fiber. This bonding method is more stable than the ionic bonds of traditional acid dyes, effectively resisting external forces such as washing and friction, and reducing the risk of fading. Simultaneously, reactive dyes are applied near the isoelectric point of cashmere (pH 4.5-5.5), preventing colorfastness degradation caused by acid and alkali damage, ensuring long-lasting color.
Low-temperature dyeing is a key technology for improving colorfastness. At high temperatures, cashmere fibers are prone to uneven dye adsorption due to scale layer shrinkage, while traditional high-temperature dyeing (above 90℃) accelerates fiber aging and affects color stability. Supreme Cashmere Series Fabrics uses low-temperature dyeing accelerators (such as the domestic surfactant WLD) to reduce the surface tension of the dye bath, promoting dye molecule depolymerization and accelerating penetration into the fiber. This process can lower the dyeing temperature by 5-10℃, reducing fiber damage while allowing the dye to form a more uniform distribution within the fiber, thereby improving color uniformity and durability.
Controlling process parameters during dyeing is equally important. Optimizing the liquor ratio (the ratio of dye liquor to fiber weight) ensures sufficient dye contact with the fiber, preventing color variations due to excessively high local concentrations. Precise matching of dyeing time and temperature ensures full dye fixation, reducing residual dye. For example, using a segmented heating process, first holding at 80℃ for 10 minutes to allow initial dye adsorption, then raising the temperature to 90℃ and holding for 50-90 minutes to complete fixation, can significantly improve color fastness. Furthermore, multiple washes with clean water (3-5 times/batch) after dyeing remove residual dye, further consolidating color stability.
Post-dyeing processes provide double protection for color durability. On one hand, treatment with environmentally friendly detergents and softeners cleans the fiber surface while forming a protective film, reducing the erosion of the dye by external factors. On the other hand, anti-pilling finishing technology reduces the risk of pilling due to fiber friction by increasing yarn twist and weaving density, preventing color fading caused by lint shedding. For example, after high-density knitting (115-130 rows/100m² in the longitudinal direction and 90-100 stitches/m in the transverse direction) and anti-pilling finishing, the fabric's anti-pilling fastness can reach 4-4.5, effectively extending color retention time.
Environmental protection and sustainability are consistently prioritized. Supreme Cashmere series fabrics strictly adheres to green standards in its dyeing process, selecting biodegradable surfactants and avoiding the use of non-degradable substances such as ABS, which are banned in the EU. In wastewater treatment, a heat recovery system is used to preheat tap water, reducing energy consumption and wastewater discharge. These measures not only meet environmental requirements but also reduce the risk of color fading due to chemical residues at the source.
Supreme Cashmere series fabrics has built a complete color durability guarantee system through optimized raw material pretreatment, selection of environmentally friendly dyes, low-temperature dyeing technology, precise control of process parameters, enhanced finishing, and environmentally friendly production processes. This system not only meets the stringent requirements of the high-end market for color stability, but also promotes the upgrading of cashmere dyeing technology towards a green and sustainable direction, setting a technological benchmark for the industry.
