Polyester yarn

polyester POY filament AAA GRADE 100% polyester yarn

What is the reason for the color fixing spots in dyeing

What is a solid stain?

When nylon is dyed with acid dyes, there are different degrees of viscous agglomerates attached to the surface of the fabric in the process of fixation. After setting, dark spots (blocks) are formed on the fabric surface, which are difficult to remove, called fixation spots.

Fixation spot is a common problem in nylon dyeing, which occurs more frequently in dry season and wet season. At the same time, it is also related to the fixing agent used. In most cases, the better the fixing effect, the higher the probability of spots.

What are the causes of solid spots?

1. High total hardness of water quality

In the process of dyeing and fixation, due to the high total hardness of water or too many unidentified impurities, insoluble precipitates formed by combining with the fixing agent adhere to the cloth surface

2. Residual weak cationic auxiliary on cloth surface

Acid fixing agent is generally a high molecular weight aromatic sulfonic acid condensate, which is anionic type. It will react with the residual cationic levelling agent on the cloth surface to produce agglomerates and form color fixing spots.

3. Improper operation

When the acid fixing agent is mixed with high concentration acid, it is easy to agglutinate and produce precipitate, and it will adhere to the cloth surface to form the color fixing spot when fixing the color; when the high concentration fixing agent is mixed, it will feed the material before it is completely dissolved, and it is also easy to form the color fixing spot.