What are the factors that affect the dyeing effect of overflow dyeing machine?

1. Dye-related factors:
Dye selection: Different dyes have different affinity and dyeing rates for different fibers. For example, reactive dyes are suitable for cotton fibers, and disperse dyes are often used for polyester fibers. If the dye is not selected properly, it may lead to problems such as weak dyeing and inaccurate color.
Dye quality: Indicators such as dye purity, particle size, and dispersibility will affect the dyeing effect. Low-purity dyes may contain impurities, affecting the purity of the color; dyes with uneven particle size or poor dispersibility are prone to precipitation or agglomeration in the dye solution, causing uneven dyeing.
Dye compatibility: When dyeing multiple colors or color matching, the compatibility between different dyes is very important. If the compatibility between dyes is not good, problems such as mutual reaction, precipitation, or color change may occur, affecting the dyeing effect.
2. Process parameter factors:
Temperature: Temperature is one of the key factors affecting the dyeing effect. For different dyes and fibers, there is a suitable dyeing temperature range. If the temperature is too low, the dye uptake rate is low and the dyeing is not sufficient; if the temperature is too high, it may cause dye decomposition, fiber damage or color change17. For example, the heating rate of disperse dyes below 90℃ can be faster, but above 90℃, especially when close to 130℃, the temperature needs to be slowly raised to avoid uneven dyeing.
Time: The length of dyeing time will also affect the dyeing effect. If the time is too short, the dye will not have time to fully dye the fiber, and the color will be light and uneven; if the time is too long, it may cause excessive dyeing, fiber damage or energy waste.
Bath ratio: Bath ratio refers to the weight ratio of fabric to dye liquor. If the bath ratio is too small, the dye liquor concentration is high, which is easy to cause uneven dyeing; if the bath ratio is too large, the dye concentration is low, the dye uptake rate is low, and the dye liquor and energy are wasted. Generally speaking, different fabrics and dyeing processes require the selection of appropriate bath ratios.
pH value: The pH value of the dye liquor has an important influence on the dyeing performance of the dye and the properties of the fiber. For example, for reactive dyes, they can only react with fibers to achieve dyeing under alkaline conditions, but too high or too low alkalinity will affect the dyeing effect.
Heating/cooling speed: If the heating and cooling speeds are too fast, the shrinkage rate of the fiber will change dramatically, resulting in problems such as folding and color flowers, especially for thermoplastic fibers such as nylon. Once folding is formed, it will be irreversible.
3. Equipment-related factors:
Nozzle: The shape, size and installation position of the nozzle will affect the spraying effect of the dye liquid and the running state of the fabric. A suitable nozzle can spray the dye liquid evenly onto the fabric to ensure uniform dyeing; if the nozzle diameter is not suitable or the installation is not firm, it may cause problems such as uneven dye liquid spraying, fabric jamming or entanglement.
Circulation system: The performance of the circulation system directly affects the circulation speed and uniformity of the dye liquid. A good circulation system can make the dye liquid flow fully in the dye tank, ensure that all parts of the fabric can be exposed to uniform dye liquid, and improve dyeing uniformity; if the circulation system fails or the flow is insufficient, it will cause uneven dyeing.
Equipment sealing: If the overflow dyeing machine is not well sealed, it may cause dye leakage, temperature instability and other problems, affecting the dyeing effect.
4. Fabric factors:
Fabric material: Fabrics of different materials have different adsorption capacity and dyeing properties for dyes. For example, natural fibers such as cotton and linen have a higher affinity for dyes and are easy to dye; synthetic fibers such as polyester and nylon have a lower affinity for dyes and need to choose suitable dyes and dyeing processes.
Fabric structure: The fabric structure, such as plain, twill, satin, etc., as well as factors such as fabric density and thickness, will affect the penetration and diffusion rate of dye in the fabric, thereby affecting the dyeing effect. Generally speaking, loose fabrics are easy to dye, while tight fabrics are more difficult to dye.
Fabric pretreatment: Fabric pretreatment, such as desizing, scouring, bleaching, etc., will affect the surface properties and dyeing properties of the fabric. If the pretreatment is not thorough, impurities and slurry on the surface of the fabric will affect the dyeing of the dye, resulting in uneven dyeing or poor color fastness.
5. Auxiliary factors:
Leveling agent: Leveling agent can improve the uniform distribution of dyes on fabrics and prevent color flowers and color differences during the dyeing process. Different leveling agents have different leveling effects on different dyes and fibers. It is necessary to select the appropriate leveling agent and dosage according to the specific situation.
Defoaming agent: During the dyeing process, the dye liquid is prone to foaming. If there is too much foam, it will affect the circulation of the dye liquid and the dyeing effect of the fabric, and even cause the dye liquid to overflow. Therefore, it is necessary to add an appropriate amount of defoaming agent to eliminate the foam.
Color fixing agent: Color fixing agent can improve the color fixing rate of dyes on fabrics and enhance color fastness. The type and dosage of color fixing agent need to be selected according to the nature of the dye and the requirements of the fabric.
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