Reasons for the yellowing of spandex fabrics

1. Since the molecular chain of spandex contains a large number of reactive groups such as amino groups, it is easy to turn yellow during high temperature setting or storage, which affects the quality of finished products, especially fluorescent whitening fabrics and light-colored fabrics.

2. In order to improve the running performance of spandex during spinning, silicone oil lubricants and other auxiliaries are used in the weaving process. These additives naturally degrade over time causing the fibers to yellow.

3. Spandex is not resistant to ultraviolet rays, and it is easy to yellow after long-term sunlight exposure, but it will not cause immediate loss of strength. Polyether spandex is more prone to yellowing than polyester spandex. When spandex is subjected to dry heat treatment, if the time is too long or the temperature is too high, it will also cause yellowing and loss of strength and elasticity. caused by oxidation. Certain nitrogen oxides, sulfur oxides, aldehydes and flue gas in the atmosphere will also cause the spandex to yellow, which will affect the appearance of the finished product. Certain unsaturated oils, unsaturated fatty acids and certain fatty substances in skin secretions have an extraction effect on certain stabilizers in spandex yarn, which will increase the sensitivity of spandex to photo-oxidation, and make spandex more prone to yellowing after sun exposure.

4. If it comes into contact with chemicals containing effective chlorine, the spandex will also turn yellow, so it is best to cover it with polyethylene film during storage.

5. In addition, spandex itself is not easy to color, that is, conventional dyes cannot make spandex color, so after the fabric is dyed, if the reduction and cleaning are not sufficient, the so-called yellowing phenomenon will also occur.