Compound reducing agent and reduction dyeing method

Abstract

The invention discloses a compound reducing agent with a stable chemical potential and not containing sodium hydrosulfite. The compound reducing agent is prepared from, by weight, 30-75% of thiourea dioxide, 60-20% of reducing sugar and 10-5% of one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid in a chemical potential control agent. By using the compound reducingagent, the dyeing process combining the pretreatment with the dyeing procedure is achieved, the treatment time is reduced, the production efficiency is improved, the dyed finished product is dyed uniformly, and the strength and hand feeling are improved.

Description

technical field [0001] The invention relates to the field of dyeing, in particular to a composite reducing agent and a vat dyeing method. Background technique [0002] Dyeing methods are generally divided into disperse dyeing, acid dyeing, reactive dyeing and other dyeing methods according to different dyes. The above dyeing methods mostly have the following problems: (1) Polyester is dyed with disperse dyes, and the light fastness is poor; after dyeing, reduction cleaning is required, and the color fastness of deep and thick colors is poor, and fades and grays after washing; When dyeing dyes, most of them need to use high-temperature process, and the cost of energy consumption is relatively high; disperse dyes are also prone to heat condensation, which is easy to cause defects such as color flowers and stains; There is a problem that it cannot meet the needs of consumers; the level dyeing property of nylon dyed with reactive dyes is poor, and high-temperature dyeing can ea...

AI Technical Summary

Problems solved by technology

The above dyeing methods mostly have the following problems: (1) Polyester is dyed with disperse dyes, and the light fastness is poor; after dyeing, reduction cleaning is required, and the color fastness of deep and thick colors is poor, and fades and grays after washing; When dyeing dyes, most of them need to use high-temperature process, and the cost of energy consumption is relatively high; disperse dyes are also prone to heat condensation, which is easy to cause defects such as color flowers and stains; There is a problem that it cannot meet the needs of consumers; the level dyeing property of nylon dyed with reactive dyes is poor, and high-temperature dyeing can easily cause the fabric to feel hard and even reduce the tear strength, especially 10-30D light and thin nylon. The strength damage is relatively large; (3) When reactive dyes are dyed in dark colors, the soaping fastness of the dyed finished product is generally poor, and it is easy to fade, lighten, and become old after repeated washing; the fabrics dyed with reactive dyes are not resistant to rinsing, if 84 disinfectant is added to the laundry It will cause partial decolorization and affect the appearance of wearing; (4) the dyeing process of acid or reactive dyes is longer, and the operation control is more difficult

Leucoic acid is difficult to process and is relatively seldom used; suspension dyeing is more commonly used, but the dye suspension is insoluble in water, and the dye molecule particles in the dye solution are large, it is difficult to fully enter the fiber, and the binding force with the fiber is weak, so The optimum level of fastness that should be achieved cannot be guaranteed; the leuco dyeing method is to convert the vat dye into the sodium salt of the leuco by pre-reduction, which is absorbed by the fiber in the dye bath, and then oxidized to form a water-insoluble dye The color lake is fixed on the fiber, which can give full play to the advantages of vat dyes

[0005] However, the existing leuco dyeing method still has the following disadvantages: the initial dyeing is faster, and it is easy to dye flowers; the amount of caustic soda and reducing agent is still high, which is easy to cause fiber damage

Some factories add softeners and antistatic agents to solve the above problems, which brings difficulties in subsequent dyeing and finishing

[0009] The dyeing of vat dyes generally adopts the suspension pad dyeing method in the pad dyeing process, and the leuco dyeing method cannot be widely used in the pad dyeing process. The main reason is that the reducing agent decomposes too fast in the leuco state, is not stable enough and the fabric Easy to dye flowers

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