Causes of clothing yellowing
1.Photo yellowing
Photo yellowing refers to the yellowing of the surface of textile clothing caused by molecular oxidation cracking reaction due to sunlight or ultraviolet light. Photo yellowing is most common in light color clothing, bleaching fabrics and whitening fabrics. After the fabric is exposed to light, the light energy is transferred to the fabric dye, resulting in cracking of dye conjugated bodies and then causing light fading and fabric surface yellowing. Among them, visible light and ultraviolet light are the main factors respectively causing the fading of azo dyes and phthalocyanine dyes.
2.Phenolic yellowing
Phenolic yellowing generally is that NOX and phenolic compounds contact and transfer and cause yellowing of fabric surface. The main reactive substance is usually the antioxidants contained in the packaging material, such as butyl phenol (BHT). After leaving factory, the clothing and footwear will be under a long time of packaging and transportation. So the BHT in the packaging material will react with NOX in the air, which leads to yellowing.
3.Oxidation yellowing
Oxidation yellowing refers to the yellowing caused by the oxidation of fabrics by atmosphere or other substances. Textile garments are usually used reductive dyes or auxiliaries in dyeing and finishing. After they contact with oxidizing gases, there will have oxidation-reduction and cause yellowing.
4.Whitening agent yellowing
Whitening agent yellowing mainly occurs on light color fabrics. When the residual whitening agent on the clothing surface migrates due to long-term storage, it will lead to excessive local whitening agent and clothing yellowing.
5.Softening agent yellowing
The cationic ions in the softening auxiliaries used in the finishing process of clothing will be oxidized when subjected to heat, light and other conditions. That results in yellowing of the softening parts of the fabric.
Although yellowing is divided into the five types mentioned above, in actual use, clothing yellowing phenomenon is usually caused by a variety of reasons.
How to prevent clothing yellowing?
1.In the production process, enterprises should try to minimize the use of whitening agent, lower than the whitening agent yellowing standard.
2.In the setting in finishing process, the temperature should not be too high. High temperature will make the dyes or auxiliaries on the surface of the fabric occur oxidation cracking, and then cause the fabric yellowing.
3.In the process of packaging, storage and transportation, there should use packaging materials with low BHT. And the storage and transportation environment should be kept at normal temperature and ventilated as far as possible to avoid phenolic yellowing.
4.In the case of phenolic yellowing of textile clothing due to packaging, in order to reduce losses, a certain amount of reduction powder can be scattered on the bottom of the packaging and the carton should be sealed for 1 to 2 days, then opened and placed for 6 hours. After the smell goes away, the clothing can be repackaged. So that yellowing can be repaired to the maximum extent.
5.In daily wearing, people should pay attention to maintenance, wash frequently and gently and avoid long time exposure.
Post time: Jun-21-2022