Analysis of the causes:
Pre-treatment oil spots are mainly expressed as oily, nearly transparent dot-like spots produced during the pre-treatment process.
The general cause is the large amount of chemical fiber oil on the fabric, and the spandex oil containing dimethyl silicone oil on the spandex fabric. After these oils were washed off in the pre-treatment process, they failed to obtain sufficient emulsification and dispersion, resulting in agglomeration back to the fabric. Especially low-grade chemical fiber fabrics use inferior chemical fiber oil or increase the amount of oiling agent, which is prone to oil spots.
For chemical fiber oil and simethicone spandex oil, choose an emulsified degreaser with excellent dispersibility to the oil, which can be used in combination with the degreaser, and can be used alone for fabrics that are not heavy.