In the process of textile processing, formaldehyde mainly comes from the following three aspects:

(1) Anti wrinkle finishing: formaldehyde containing crosslinking agent is still widely used in anti wrinkle, anti wrinkle and non iron finishing. If not properly used, its concentration will exceed the allowable range.

(2) Improve color fastness: cheap formaldehyde containing auxiliaries are often used for direct dyes and occasionally for post-treatment of reactive dyes. According to the formula used, it is easy to exceed the limit of 20mg / kg in class a products, or even the limit of 75mg / kg in class B products. At present, some cationic auxiliaries with or without formaldehyde are on the market, such as Xili A and B.

(3) Pigment printing: high quality formaldehyde containing crosslinker is widely used in pigment printing process, which means that it is almost impossible to meet the 75mg / kg limit even if it is used carefully. Now there is a very low formaldehyde content of cross-linking agent supply, that is, in the presence of urea reagents and formaldehyde can be used together to achieve the purpose of formaldehyde free paint printing.