Why does the fastness of qualified fabrics deteriorate after being shipped to customers?

The thermal migration of disperse dyes is an inherent physical property of disperse dyes. Thermal migration is common regardless of the type of disperse dyes, but the molecular structure is different and the degree of thermal migration is different. During long-term storage and transportation, disperse dye dyes will also undergo thermal migration.

The thermal migration of disperse dyes and sublimation fastness are two different concepts because they are produced by different mechanisms. Sublimation is the vaporization of dyes under the influence of various factors and the transfer of single molecules; thermal migration is the transfer of dyes in solid single molecules or gels.

The impact of thermal migration of disperse dyes:

1. The color light of the dyed object changes;

2. The friction fastness decreases;

3. The fastness to washing and sweat decreases;

4. The fastness to sunlight decreases;

5. The fastness to dry cleaning decreases;

6. It causes staining of other fabrics during ironing, etc.

Causes of thermal migration of disperse dyes:

Thermal migration is a redistribution phenomenon of disperse dyes in a two-phase solution (fiber and auxiliaries). Under high temperature or long-term storage conditions, the dye is dissolved by the auxiliaries remaining in the outer layer of the fiber and moves the dye to the fiber surface.

Fiber residual auxiliaries generally come from:

1. Oils, antistatic agents, etc. added during spinning or weaving;

For reference: Which oils should be removed in polyester pre-treatment degreasing?

2. Various auxiliaries added during dyeing and finishing, such as refining agents, softeners, etc.; non-ionic surfactant residues are more likely to cause thermal migration of dyes;

please note:

1.The sublimation fastness of disperse dyes has no absolute correlation with thermal migration;

2.Disperse dyes with different structures have different thermal migration under the same conditions.

Prevention of thermal migration of disperse dyes:

1. All oils (auxiliaries) added during spinning or weaving should be removed;

2. When formulating the process flow, the auxiliaries used in pre-treatment and dyeing should be washed as clean as possible;

3. When selecting post-treatment auxiliaries, thermal migration should be tested.

4. Detection of thermal migration of fabrics:

Use dimethylformamide (DMF) as a solvent, put the dyed fabric into it at room temperature for 3 minutes, and the dye that migrated to the fiber surface will fall into DMF. The amount of dye shedding can determine the degree of thermal migration of disperse dyes in the fabric.