Effect of pH value on sock quality during dyeing

Effect of pH value on sock quality during dyeing

Dyeing is crucial in the production process of socks, and the pH value during dyeing has a profound impact on the quality of socks in many aspects.

1. Effect of pH value on dye uptake
Differences in dye uptake characteristics of dyes at different pH values: Various dyes have their appropriate pH value range. Taking reactive dyes as an example, cotton fibers are usually best dyed under weak alkaline conditions. If the pH value is too high or too low, the dye uptake rate may decrease. For example, when the pH value is too high, the reactive groups in the reactive dyes may have a weakened ability to react with the hydroxyl groups in the cellulose fibers, making it difficult for the dyes to firmly attach to the fibers, reducing the dye uptake rate and insufficient color saturation.
Impact on dyeing uniformity: The instability of pH value can also lead to uneven dyeing. During the dyeing process, if the pH value fluctuates, the dissociation state and aggregation degree of the dye in the dye solution will change, thereby affecting the chance of dye molecules combining with fibers. For example, when dyeing polyester fibers with disperse dyes, if the pH value changes and causes the dye to aggregate, the dye will be unevenly adsorbed and diffused on the fiber surface, which will eventually lead to uneven color depth of the socks, color spots, and other problems, which seriously affect the appearance and quality of the product.

2. The influence of pH value on fiber performance
Change the chemical structure of the fiber: Different fibers have different chemical stability and reactivity at a specific pH value. For cotton fibers, they are relatively stable under acidic conditions, while under strong alkaline conditions, cellulose will dissolve or degrade, resulting in a decrease in fiber strength and weakening of strength, affecting the durability of the socks.
Affect the feel and gloss of the fiber: pH value will also affect the surface structure and morphology of the fiber, thereby changing the feel and gloss of the fiber. If the pH value is not adjusted to the appropriate range after dyeing, the fiber surface may become rough, the feel will be hard and astringent, the gloss will become darker, and the wearing comfort and beauty of the socks will be reduced.

3. The influence of pH value on color fastness
Water washing color fastness: The appropriate pH value helps to improve the water washing color fastness of dyed socks. When the pH value is too high or too low, it may destroy the chemical bond between the dye and the fiber, making the dye more likely to fall off the fiber. For example, under acidic conditions, the hydrolysis reaction of some dyes will accelerate, resulting in reduced color fastness to washing. Under alkaline conditions, some dyes may undergo redox reactions, which also affect their fastness on the fiber.
Color fastness to rubbing: pH value will also affect the color fastness to rubbing of socks. If the pH value is not suitable after dyeing, the adhesion between the fiber and the dye will be weakened, and the dye particles will fall off more easily during friction, causing the socks to fade easily during wearing and washing, affecting the wearing life and appearance quality.

4. Impact of pH value on the environment
Wastewater treatment: Too high or too low pH value during the dyeing process will increase the difficulty of wastewater treatment. Too high pH value will make the wastewater highly alkaline, causing corrosion and damage to wastewater treatment equipment and biological treatment systems; while too low pH value will make the wastewater highly acidic, which will also have an adverse effect on wastewater treatment facilities. In addition, excessive pH may inhibit the activity of microorganisms, affect the biodegradation effect of wastewater, and increase the cost and difficulty of wastewater treatment.
Environmental protection and sustainability: From the perspective of environmental protection and sustainable development, controlling the pH value in the dyeing process within a reasonable range, reducing the amount of acid and alkali, and reducing the pH value of wastewater are of great significance for reducing environmental pollution and waste of resources.

5. How to control the pH value in the dyeing process
Reasonable selection of dyes and auxiliaries: According to the fiber type and color requirements of the socks, select suitable dyes and auxiliaries, and understand their performance characteristics under different pH values. For example, for acid dyes, dyeing can be carried out under weak acid conditions; for direct dyes, dyeing can be carried out under neutral or weak alkaline conditions.
Accurate pH adjustment: During the dyeing process, use accurate pH adjusters, such as acetic acid, sodium carbonate, etc., according to the requirements of dyes and auxiliaries, adjust the pH value of the dye liquor to the optimal range and keep it stable. At the same time, the pH value of the dye liquor should be monitored regularly and adjusted in time.
Strengthen washing and post-treatment: After dyeing, sufficient washing should be carried out to remove the residual dyes, auxiliaries and chemicals on the fiber surface. At the same time, appropriate post-treatment processes, such as neutralization treatment and softening treatment, can be used to further adjust the pH value of the socks to improve their color fastness and wearing comfort.

6. Actual case analysis
Take a socks manufacturer as an example. During a production process, due to improper pH control during dyeing, a batch of socks had uneven colors, and the color fastness to washing and the color fastness to rubbing did not meet the standard requirements. After analyzing and adjusting the dyeing process, the pH value of the dye solution was strictly controlled within the appropriate range. After re-production, the color of the socks was bright and uniform, and all color fastness indicators met the requirements, and the product quality was significantly improved.

In summary, the pH value during the dyeing process has a vital impact on the quality of socks. As an international wholesale buyer, when selecting socks suppliers and product quality assessment, full attention should be paid to the pH value control during the dyeing process to ensure the purchase of high-quality and environmentally friendly socks.