Dyeing method for leuco body pad dyeing

Abstract

The invention discloses a dyeing method for leuco body pad dyeing. The dyeing method includes the following steps of padding, oxidizing and washing, wherein the padding technology includes of paddingin a dye vat with a penetrating agent and padding in a dye vat with leuco body sodium salt dye liquor, the leuco body sodium salt dye liquor is prepared from a composite reducing agent and dye, and the composite reducing agent includes one or more of thiourea dioxide, reducing sugar, a chemical potential control agent, sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid. By the adoption of the composite reducing agent, a leuco body reducing method is applied and implemented in pad dyeing, and an obtained dyed product is deep in color and high in fastness.

Description

technical field [0001] The invention relates to the field of dyeing, in particular to a leuco-padding dyeing method. Background technique [0002] Dyeing methods are generally divided into dyeing methods such as disperse dyeing, acid dyeing and reactive dyeing 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 dyeing of reactive dyed nylon is poor, and high-temperature dyeing can easily cause the fabric to feel hard and even r...

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 dyeing of reactive dyed nylon is poor, and high-temperature dyeing can easily cause the fabric to feel hard and even reduce the tear strength, especially 10D-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

Leuco 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 molecular 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 still has the following disadvantages: because the initial dyeing is fast and easy to dye flowers; the consumption of caustic soda and reducing agent is still high, which easily causes fiber damage

[0008] The dyeing of vat dyes generally adopts the suspension pad dyeing method. The main reason is that the reducing agent decomposes too fast in the leuco state, is not stable enough, and the fabric is easy to be dyed.

As a result, the leuco dyeing method cannot be widely used in the pad dyeing process

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