The role of color fixative in improving the color fastness of socks to sweat stains

The role of color fixative in improving the color fastness of socks to sweat stains

I. Introduction
In textile production, color fastness is one of the important indicators to measure product quality. Especially for socks worn close to the body, color fastness to sweat stains is even more critical. As a commonly used auxiliary agent, color fixative can significantly improve the color fastness to sweat stains of socks, thereby extending the service life of the product and improving consumer satisfaction.

2. Basic principles of color fixative
Ionic bond bonding
The cationic groups (such as quaternary ammonium salts or tertiary amine salts) in the color fixative molecules can form ionic bonds with the anionic groups in the dye molecules, so that the dye and the color fixative are combined into insoluble color blocks, thereby improving the adhesion of the dye to the fiber.
Film-forming properties
The color fixative forms a protective film on the fiber surface, wrapping the dye inside the fiber to prevent the dye from falling off due to sweat or friction. This film-forming property can effectively improve the color fastness to sweat stains.
Cross-linking reaction
The reactive groups in the color fixative molecules can undergo cross-linking reactions with the dye and cellulose molecules to enhance the binding force between the dye and the fiber, thereby improving color fastness.

3. Factors affecting color fastness to sweat stains
Floating color problem
When there is floating color of dyes that are not stably bound to the fiber on the surface of socks, the acid-base environment in the sweat will promote the migration of dyes and cause staining.
Auxiliary agent residue
If the auxiliaries added during dyeing and post-treatment are not fully removed, they may cause dye migration under high temperature or sweat, affecting the color fastness to sweat stains.
The influence of retarder
Although the retarder used in the dyeing process can dye evenly, it will weaken the binding force between the dye and the fiber, thereby reducing the color fastness to sweat stains.
pH value and temperature
The pH value and temperature of sweat have a significant effect on the color fastness to sweat stains. Constant pH value and temperature are important conditions to ensure the accuracy of test results.

4. The application of color fixatives in improving color fastness to sweat stains
Choosing suitable color fixatives
Different types of color fixatives are suitable for different fibers and dyes. For example, quaternary ammonium salt polyamide color fixatives have a significant effect on improving the sweat fastness of acid dyes.
Optimize the color fixing process
Immersion method: immerse the socks in the color fixing agent solution and maintain a certain temperature and time to ensure that the color fixing agent fully penetrates into the fiber.
Padding method: The color fixing agent is evenly distributed on the fiber surface by rolling the liquid to improve the color fixing effect.
Combined with other additives
The color fixing agent can be used in combination with a wet friction enhancer or adhesive to simultaneously improve the color fastness to sweat and the fastness to friction. For example, the polymerization of acrylic monomers can significantly improve the color fastness to sweat and the fastness to wet friction.

5. Environmental protection of color fixing agents
With the improvement of environmental protection requirements, formaldehyde-free color fixing agents have gradually become the mainstream. This type of color fixing agent can not only effectively improve color fastness, but also avoid harm to the environment and human health.

6. Practical application cases
Improvement of color fastness to sweat of nylon socks
By using quaternary ammonium salt polyamide color fixing agents (such as SF-30A), the color fastness to sweat of nylon socks is significantly improved, and the wet friction fastness is also improved.
Optimization of color fastness to sweat of cotton socks
The use of formaldehyde-free color fixative to treat cotton socks not only improves the color fastness to sweat, but also maintains the softness and color brightness of the fabric.

7. Conclusion
Color fixative plays an important role in improving the color fastness of socks to sweat. By rationally selecting color fixatives, optimizing processes and combining with other auxiliaries, the color fastness of socks can be significantly improved to meet consumers' demand for high-quality textiles. At the same time, the application of environmentally friendly color fixatives also provides a new direction for the sustainable development of the textile industry.