What is the function of the fixing agent used to improve the wet processing fastness?

(1) Generate insoluble lakes on the fabric and block the soluble groups, so that the dye on the fabric is not easy to dissolve and fall off when exposed to water, so as to achieve the purpose of improving the wet processing fastness. However, after the fixing agent is fixed, it is easy to change the shade of the dyed material or cause the light fastness to decrease.

(2) A mesh film is formed on the fabric to prevent the dye from falling off.

(3) The reactive groups in the fixing agent molecules are cross-linked with the reactive groups on the dye molecules and the hydroxyl groups on the cellulose molecules to improve the fixing effect of the dye on the fiber.

(4) Utilize the molecular attraction between the fixing agent and the fiber to increase the fixing strength of the fixing agent, thereby improving the color fastness.

Generally speaking, a good fixing agent should have the following properties:

It has a strong fixing ability, which can significantly improve the related color fastness of the fabric; 

The dye has a wide adaptability, and the dye structure has little effect on the fixing effect; 

It has a strong affinity with the fiber and has a high exhaustion rate in the fixing bath; 

After the fabric is fixed by the fixing agent, it will not cause color change; 

While improving the related color fastness (such as washing fastness), other color fastness (such as light fastness) should not be reduced; 

The feel of the fabric does not cause the strength of the fabric to decrease.