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The Types Of Dye-Fixing Agent

The Types Of Dye-Fixing Agent

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1. Reactive dye-fixing agent
Reactive fixing agent is usually introduced reactive group in the fixing agent molecules,the commonly used reactive group here is the epoxy group. This dye-fixing agent will combine some groups in fiber dye molecules and form covalent bond, which is helpful to the fastness. The commonly used reactive dye-fixing agent is as follows:
(1)The reactive cationic resin type fixing agent is usually produced by the reaction of diethylenetriamine , dicyandiamide and the epichlorohydrin (the introduction of epoxy group). It can not only improve the color fastness of direct dyes and acid dyes, but also does not change the color.
(2)Polyether reactive fixing agent, is a kind of non-ionic polyether fixing agent produced by the reaction of polyether and epichlorrohydrin. This agent has a certain solubility in water. It can be cross-linked into macromolecular network structure in itself. Combining with dye, it will form large molecular compounds. the dye and fiber combined together firmly and then improve the wet fastness.
(3)Quaternized reactive fixing agent, is usually product by the reaction of  trimethylamine, diethylenerriamine and epichlorohydrin. It is commonly used as fixing agent, but the color fastness is not very good. However, because of its cationic group and crosslinking with fiber, it can make cellulose fiber modified. It is an effective way to realize the salt free or low salt dyeing and improve the dye uptake rate.

2. Non-reactive dye-fixing agent
The fixing principle is forming film on the surface of fiber and closing water soluble groups. its mainly divided into cationic fixing agent and resin type fixing agent.
(1)By combining the cationic and the anionic group in the dye molecule, it will form into ionic bond and close water-soluble groups, thus the cationic dye-fixing agent will improve wet fastness of fabric. The cationic dye-fixing agent can be divided into:
① Cationic surface activity fixing agent: most of the surfactant have the dye-fixing effect in varying degree. This kind of dye-fixing agent include cetyl pyridinium chloride and Sapamin type cationic surface active agent. But because of it bad soap washing fastness and light fastness, it is seldomly used. And it typical structure is as follows:
②Non-surface-active quaternary ammonium salt, is a king of dye-fixing agent neither belongs to resin nor surfantant, which typically contains two or more than two quaternary amine, which belongs to the polyamine derivatives. Such as, 一N+(CH3)2一CH2CH2一N+(CH3)2一 and the macromolecule condensation compound of polyamine and cyanuric chloride. This kind of fastness will improve the washing fastness and the strength of direct dye. But it have less influence on the light fastness and color. It is seldomly been used at home.

3. Resin dye-fixing agent
This kind of fixing agent is a water soluble resin with stereochemical structure, and it is currently the largest use of agent types, accounting for about 70% to 80% of the total amount. Its representative product is fixing agent Y.
① dichloramineand formaldehyde initial body, its water solution is dye-agent Y, cationic, it will combine with the anionic dye, such as direct dye and acid dye,forming insoluble color lake, covering on the surface of fiber and achieving dye-fixing purpose. Because of its influence on light fastness, add metal salt in the dye fixing agent, the light fastness will be improved. For example, dye-fixing agent M is the resin type dye-fixing agent of copper salt complex.But owing to the copper salt will be stripped by sweat solution from the fiber, it will cause the excess of the heavy metal content on the fabric. There other dis advantage is that the free-formaldehyde released from dye-fixing agent on the fabric. And the quantity is usually above the limit. So at present, people usually choose formaldehyde-free and low-formaldehyde dye-fixing agent.
②The polyamines is the water soluble resin produced by helium taking-off reaction of guanidine classes and polyene polyamine compounds and hydrochloric acid ,urea. It do not contain free formaldehyde. It is cationic and net structure. It can combine with the anionic dye and form macromoleculaarr compound. And it can improve the wet fastness. The using quantity and the fixing condition is similar to dye-agent Y.  This is the quicker developed types in China, mainly used in the fixation of reactive dyes and direct dyes.
③The quaternary ammonium salt polymer is a polymer, homopolymer or copolymer formed from the polymerization of olefins with quaternary amino groups. Through the film property of ploymer resin and cationic group on the polymer chain, achieve the purpose of color fixing. It is water-soluble, especially suitable for reactive dyes. the treated fabric is bright-colored, sun-proof, perspiration resistant, good fastness.and it can protect the reactive dyes from acidic atmosphere, but washing fastness is bad in high temperature.

4. New dye-fixing agent
With the progress of science and technology, the environmental awareness and quality of life have been greatly improved , the requirements on textiles has been increased , this also requires for dyeing auxiliaries to be environmental protection, high efficiency and energy saving, formaldehyde free or low formaldehyde fixing agent has been used in recent years and there are some new type ones emerged.
Sol-gel dye-fixing agent is still in the research stage. Its fixation mechanism is easy because nano colloidal can be modified chemically or physically. Through padding or dipping treatment and after drying, it will form a metal or non-metal oxide film on the surface of textiles, fixing the dye. Thus, it will improve the fastness.
In recent years, polyurethane production technology is developed greatly. and it is environmental protection, it offer the opportunity of high performance synthetic fixing agent. Waterborne polyurethane can improve the dyeing fabric color and it is stain resistance and wear resistance.  The aqueous polyurethane of amine compounds will compound with the negative ion water-soluble dyes like direct dyes, acid dyes and reactive react, reaching the fastness result..

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