Definition of non formaldehyde dye fixing agent

At present, color fixing agent can be divided into cationic fixing agent, resin type fixing agent (containing formaldehyde resin type fixing agent containing polyamine resin type fixing agent) and cross linking reaction type fixing agent.

The mechanism of color fixing agent which can improve the dyeing fastness of dye solution on the fiber is through

(1) the quaternary ammonium salt or tertiary amine salt in color fixing agent molecules, when in acidic medium, relying on a combination of anionic ionic bond strength of cationic and anionic dyes in the structure and form insoluble fiber deposition in the inside and outside the lake;

(2) reactive binding groups in color fixing agent molecules covalently links active group covalent bond in fibers and dyes;

(3) Fabric which is treated by color fixing agent in the drying process, the reactive binding group on the color fixing agent molecules associate group agent cross linking into large molecules in the fiber and fabric surface, to form a layer of protective film with certain strength. Thus the dye will be coated on the fiber, which make the dye is not easy to fall off;

(4) Pro structural groups on the molecules of color fixing agent, which making the combination of hydrogen bond and van Edward forces between dyes and color fixing agent;

(5) Groups in fixing agent molecules such as imino, combining with O, N atoms in the dye molecules, forming coordination bond, and form chelate.

According to the mechanism of color fixing agent, the chemical structure of color fixing agent should be cationic; there must be reactive binding groups which can crosslink by themselves and whose molecular weight is large enough to form a protective film on the drying process. And the structure of groups can contain affinity and dye, also have the precipitation and complexation of metal ions. In addition, non formaldehyde dye fixing agent requires no using of the raw material which having formaldehyde containing in the production. The production process and fixation process should also not produce formaldehyde. And fabrics after color fixing process will not release formaldehyde.

Classification of non formaldehyde dye fixing agent

1. Cationic resin type

Cationic resin type non formaldehyde dye fixing agent, can use two ethylene reaction, three amine and methylol urea to form imidazoline. It is cationic , namely, color fixing agent DFRF-1 (produced by Shanghai Textile Auxiliaries Factory ), strictly speaking, color fixing agent DFRF-1 can be called a non formaldehyde dye fixing agent.

Because they still have to use 2D resin or methylolurea as crosslinking agent, can only be called low formaldehyde dye fixing agent. Make two ethylene three amine condense with dicyandiamide, ammonia and undergo the ring structure of prepared , then achieve color fixing agent SH-96 with imidazoline structure, and also is resin type color fixing agent. The disadvantage is it will have a pale phenomenon. According to current knowledge, to use dicyandiamide as the raw material of the fixing agent will have discoloration phenomenon, so it is necessary to control the amount of usage, in order to reduce the degree of discoloration.

Make dicyandiamide condense with B two aldehyde, which can form a ring structure condensates. In general, it does not release formaldehyde and also has the fixing effect of resin type color fixing agent made of dicyandiamide. It has darker color and usually is brown or light brown solution.