How to prevent yellowing of all cotton composite fabric? The fluorescent whitening agent on the market has high and low temperature resistance performance of two kinds, low temperature type can only withstand <130-140 degrees Celsius, high temperature tolerance >200 degrees celsius.
If the fabric is yellowing after dyeing and finishing, this problem is due to the fact that the treatment aids are not resistant to high temperature, especially the fluorescent whitening agent / softener.
In the cotton / polyester blended fabric with fluorescent whitening agents must be considered in setting the temperature set at 180-185 degrees, so the temperature is not adaptable to low temperature type fluorescent whitening agent, is called yellow.
In addition, if the so-called yellowing is occurred after the completion of dyeing and finishing of the fabric storage, it may be in the dyeing and finishing process, cleaning is not sufficient, there are remnants of dyeing and finishing chemicals.
Since the questioner did not explicitly explain the yellow change at that stage of operation.
In the same way, the choice of softeners, if not considered, can also cause yellowing.