Why has the fastness of fabrics stored in the warehouse deteriorated?

Because the dyestuff on the fabric has undergone heat migration.

What is heat migration?

Heat migration is a phenomenon that occurs when polyester dyed with disperse dyes is treated at high temperatures and the dyes are subjected to heat migration.

I. Effects of heat migration:

1. change in the colour and light of the dyed material;

2、Decrease in rubbing fastness;

3. Decrease in washing and perspiration fastness;

4. Decrease in fastness to sunlight;

5. Decrease in fastness to dry-cleaning;

6. Staining of other fabrics during ironing, etc.

II. Causes of heat migration:

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

Fibre residual auxiliaries are generally derived from:

1, oils, antistatics, etc. added during spinning or weaving

2. various auxiliaries added during dyeing and finishing, such as refiners, softeners etc.; non-ionic surfactant residues are more likely to cause thermal migration of dyestuff;

PS:

1. there is no absolute correlation between the fastness to sublimation of disperse dyes and heat migration;

2. The heat migration of disperse dyes of different structures under the same conditions is different.

III. How to prevent:

1. Oil agents (auxiliaries) added in the spinning or weaving process should be removed;

2, pre-treatment, dyeing additives used in the process development, as far as possible to wash clean;

3, post-treatment auxiliaries selected to test the heat migration.

IV. How to test:

Dimethylformamide (DMF) is used as the solvent, and the dyed fabric is put into it at room temperature for 3min, and the dye that has migrated to the surface of the fibre will fall off into the DMF, the amount of dye falling off can determine the degree of heat migration of the disperse dyes in the fabric.

Edit by Edie

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