In textile printing processing, the selection and application of printing auxiliaries directly affect the color performance, feel and durability of the finished product. From grey cloth pretreatment to printing fixation, and then to post-finishing, different processes need to match specific auxiliary systems. This article will systematically analyze the scientific application of printing auxiliaries in the complete production process to help practitioners optimize the process and improve product stability.

1. Pretreatment stage: Laying the foundation for printing

Pretreatment is the key guarantee for printing quality, mainly involving desizing, refining and bleaching. This stage requires the use of:

Penetrant: Improve the wettability of grey cloth and ensure uniform penetration of subsequent chemicals (such as anionic sulfonates).

Chelating agent: Soften water quality to prevent metal ions from combining with dyes to cause color spots (use environmentally friendly organic chelating agents).

Oxygen bleaching stabilizer: Control the decomposition rate of hydrogen peroxide during bleaching to avoid fiber damage.

Common problems: If the pretreatment is not sufficient, it is easy to cause color spots and uneven penetration after printing.

2. Printing process: synergistic enhancement of auxiliaries

During the printing stage, special auxiliaries need to be matched according to the dye type (active, dispersed, acidic, etc.):

Thickener: Construct a dye transfer system to affect the clarity of printing (compounding sodium alginate with synthetic thickeners can balance cost and performance).

Urea: As a hygroscopic agent in reactive dye printing, it promotes dye dissolution and fiber swelling.

Resistant salt: Prevents premature reduction of dyes, especially important for vat dye printing.

Case description: A factory uses a composite thickener in cotton fabric printing, which reduces the blocking rate by 40% and significantly improves the clarity of pattern contours.

3. Finishing stage: function and feel regulation

Finishing auxiliaries determine the performance of fabrics:

Color fixative: Cationic polymers can improve the wet friction fastness of reactive dyes (pay attention to pH adaptability).

Softener: Silicone oil products can improve the feel, but excessive use may affect hydrophilicity.

UV resistant auxiliaries: Suitable for outdoor textiles, extending color durability by absorbing or reflecting ultraviolet rays.

Note: The addition of finishing auxiliaries needs to consider the compatibility with the previous process. For example, silicone softeners may affect the lamination effect of the coating.

4. Environmental protection and process optimization trends

As regulations become stricter, the industry is transforming towards low COD and APEO-free auxiliaries:

Biological enzyme desizing agent: replaces traditional alkali desizing and reduces the wastewater treatment load.

Water-based acrylic thickener: reduces VOC emissions and complies with EU REACH standards.

The application of printing auxiliaries is a systematic project throughout the entire printing and dyeing process, and needs to be scientifically proportioned according to fabric characteristics, dye types and environmental protection requirements. It is recommended that companies optimize the combination of auxiliaries through small tests and regularly test the key indicators of finished products (such as color fastness, formaldehyde content, etc.) to achieve a balance between quality and efficiency.