CN111335047A

CN111335047A - Novel one-bath dyeable vat dye and dyeing method thereof

Info

Publication number: CN111335047A
Application number: CN202010265545.0A
Authority: CN
Inventors: 周长文; 李瑞卿; 张淑桃; 王伟
Original assignee: Foshan Changran Technology Co ltd
Current assignee: Foshan Changran Technology Co ltd
Priority date: 2020-04-07
Filing date: 2020-04-07
Publication date: 2020-06-26

Abstract

The invention discloses a novel one-bath dyeable vat dye and a dyeing method thereof. The vat dye comprises 15-35 wt% of dye matrix, 5-15 wt% of composite reducing agent, 5-20 wt% of alkali, 1-3 wt% of dispersing agent, 0-5 wt% of surfactant and 30-60 wt% of water. The novel one-bath dyeable vat dye is used for dyeing, the shortening of the dyeing process and the novel dyeing process combining the pretreatment and the dyeing process are realized, the treatment time is reduced, the production efficiency is improved, the dyeing of the dyed finished product is uniform, and the strength and the hand feeling are improved.

Description

Novel one-bath dyeable vat dye and dyeing method thereof

Technical Field

The invention relates to the field of textile dyeing, in particular to a novel one-bath dyeable vat dye and a dyeing method thereof.

Background

Dyeing methods are generally classified into disperse dye dyeing, acid dye dyeing, reactive dye dyeing, vat dye dyeing and the like according to the difference of dyes. The polyester is dyed by adopting disperse dyes, so that the light fastness is poor; reduction cleaning is needed after dyeing, the color fastness of deep color is poor, and the color fades and becomes grey after cleaning; most of disperse dyes need to adopt a high-temperature process during dyeing, so that the energy consumption cost is high; the disperse dye is also easy to generate thermal coagulation, and easily causes defects such as color spots, color spots and the like; when the acid dye is used for dyeing nylon, the light fastness and the soaping fastness of a finished product have the problem that the requirements of consumers cannot be met; the level-dyeing property of reactive dye dyed nylon is poor, the hand feeling of the fabric is hard and even the tearing strength is reduced easily due to high-temperature dyeing, and particularly the strength damage of 10-30D light and thin nylon is large; when the reactive dye is dyed with dark color, the soaping fastness of a dyed finished product is generally poor, and the dyed finished product is easy to fade, lighten, age and the like after being washed for many times; the fabric dyed by the reactive dye is not resistant to rinsing, and if 84 disinfectant is added during washing, local decolorization is caused, so that the wearing attractiveness is affected; the dyeing process of the acid or reactive dye is longer, and the operation control difficulty is increased.

While the vat dye dyed products have excellent color fastness and stability against chemical treatment. In terms of color fastness, most varieties of the dye are very excellent in light fastness, and especially the fastness to (chlorine) bleaching and the fastness to chlorine water are inaccessible to dyeing by other dyes; in addition, the performance of strong alkali, strong acid and oxidation reducing agent resistance is also excellent; the advantages determine that the vat dyes can be widely applied to dyeing of various uniforms, women and children clothes and frock textiles, particularly dresses of caregivers and clothes of medical care personnel needing to work in outdoor severe environment for a long time, and the like. Along with the increasing improvement of the living standard of people, the richness requirements on the colors and patterns of the textiles are also continuously improved, and the dyeing (such as yarn and loose fiber dyeing) before weaving the textiles is also adopted more and more; the dyeing method before weaving has higher requirements on the selection of dyes and processes, and the requirements that the color cannot be destructively influenced in the subsequent dyeing and finishing (such as strong alkali mercerization and the like) processing can be met, and the requirements can be met to the maximum extent by reducing the dyes.

The vat dyes are dyed by methods such as leuco acids, suspensions, leuco bodies and the like. The processing and treatment of the leuco acid are difficult and less; suspension dyeing is common, but the dye suspension is insoluble in water, dye molecules in dye liquor are large in particle size, cannot enter the fiber fully, and the bonding force with the fiber is weak, so that the optimal fastness level which is reasonably reached cannot be ensured; the leuco dyeing method is to convert vat dye into sodium salt of leuco, which is adsorbed by fiber in dye bath and oxidized to form water insoluble dye lake fixed on fiber.

However, the existing leuco body dyeing method still has the following defects: the initial dyeing is fast and the dyeing is easy; the dosage of the caustic soda and the reducing agent is still high, and the fiber damage is easy to cause. At present, most of factories adopt sodium hydrosulfite as a reducing agent, and the sodium hydrosulfite is decomposed too fast, so that the decomposition rate and factors influencing the decomposition are more, the reduction potential value change range is large, and the color is difficult to control. In actual operation, sodium hydrosulfite needs to be added for many times, so that the consumption of sodium hydrosulfite is large, waste is caused, and the environment is polluted.

In the prior art, commercial vat dyes exist in an oxidation state, and the dye in the oxidation state has poor water solubility and unstable dye liquor; since its dyeing mechanism is roughly summarized as oxidized dye-converted to reduced state by the action of a reducing agent-dyed-converted to oxidized state-fixed; the existing reduction dyeing process has longer working procedures, if the reduction dye matrix is directly prepared into a stable reduction state, namely a reduction dye leuco sodium salt system, the process flow of a printing and dyeing mill can be shortened, the production cost is reduced, better dyeing color light and color fastness can be obtained, and the value of developing a novel one-bath dyeable reduction dye and a dyeing method is the same.

The dyeing of the conventional fabric generally comprises the steps of pretreatment, desizing, refining and the like, and then enters the dyeing step. Desizing and refining are mainly to remove oil added in the spinning and weaving processes, oil stains, dust and the like which are stained in storage and transportation; the desizing and refining are generally carried out by treating the slurry under alkaline conditions at a high temperature of 80 ℃ or higher (generally 95 ℃ in a factory) for 30 minutes or more, or by treating the slurry with an oxidizing agent and an alkali. After pretreatment, dyeing can be carried out after the pretreatment and the full cleaning. Has the problems of more production processes, high water consumption, high energy consumption, low productivity and the like. The dyeing process of dip dyeing needs to be gradually heated from low temperature to a high temperature area, the dyeing is carried out for more than 30 minutes, after liquid drainage, the dyeing is carried out for a plurality of times of hot washing, cold water washing, reduction washing, and finally the dyeing is taken out of a vat. Generally, the nylon dyeing high-temperature area is 98 ℃, the polyester dyeing high-temperature area is more than 120 ℃, and the high temperature can damage the strength of the fiber and consume more energy. Acid is needed to neutralize the raw cotton loose fibers and yarns during pretreatment boiling and bleaching, and under the violent action of caustic soda and hydrogen peroxide, the surfaces of the cotton fibers are too clean, so that the hand feeling of the cotton fibers is hardened, broken ends are increased during spinning, and the strength of a woven product is reduced. The softening agent and the antistatic agent are added in a factory to solve the problems, the subsequent dyeing and finishing processing is difficult, the process is complex, the wastewater discharge and the water and electricity consumption are increased, and the energy conservation and the environmental protection are not facilitated.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention provides a novel one-bath dyeable vat dye which does not contain sodium hydrosulfite, has stable chemical potential and stable system, and a preparation method of the dye.

The invention also provides a one-bath dyeing method adopting the vat dye, which integrates pretreatment and dyeing procedures into a whole, reduces the procedures and improves the production efficiency; the refining and dyeing temperature can be controlled below 80 ℃, and the fiber strength is protected, and meanwhile, the obvious effects of energy conservation and consumption reduction are achieved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a novel one-bath dyeable vat dye comprises a vat dye matrix, a composite reducing agent, alkali, a high-efficiency dispersing agent and a surfactant.

Furthermore, the vat dye is a composite system formed by reaction and compounding of a vat dye matrix, a composite reducing agent, alkali, a high-efficiency dispersing agent and a surfactant, and an object to be dyed is directly dyed and fixed in a dye solution prepared from the vat dye matrix, the composite reducing agent, the alkali, the high-efficiency dispersing agent and the surfactant without a longer process flow of dyeing, reduction and oxidation fixation of the traditional vat dye suspension.

Wherein, the dye matrix is from the existing vat dye and the suitable variety is selected; composite reducing agent, including selected reducing agent and chemical potential control agent; the alkali is a substance which has buffer performance, can provide relatively stable alkalinity and is well compatible with other components of the dye liquor; the high-efficiency dispersant can ensure that the aqueous dye keeps stable in the using and storing processes; through the synergistic effect of the different components, the novel one-bath dyeable vat dye system is stable, the chemical potential is very stable, the composite reducing agent in the dye is slowly decomposed, the over-reduction reaction with the dye can be reduced, and the excellent dyeing effect, the stable quality and the lower processing cost are obtained.

The composite reducing agent comprises 30-75 wt% of thiourea dioxide, 20-60 wt% of reducing sugar and 5-10 wt% of chemical potential control agent; the chemical potential control agent is at least one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid.

The alkali is one or the combination of caustic soda, sodium carbonate or disodium hydrogen phosphate, and is selected according to the fiber characteristics of different objects to be dyed. For example, when dyeing terylene and nylon, the fiber is easy to be damaged under the action of alkali, and combined alkali is needed; when the cotton fiber is dyed, caustic soda can be adopted due to strong alkali resistance of the cotton fiber, and the caustic soda is used for carrying out Candida utilis treatment on the cotton fiber, so that the dye uptake is improved.

The dispersant is a product commonly used in the field; the surfactant is selected from surfactants with wetting, penetrating and defoaming effects.

Further, the novel one-bath dyeable vat dye also comprises water, wherein the vat dye matrix is 15-35 wt%, the composite reducing agent is 5-15 wt%, the alkali is 5-20 wt%, the dispersing agent is 1-3 wt%, the surfactant is 0-5 wt%, and the water is 30-60 wt%.

The invention also provides a preparation method of the novel one-bath dyeable vat dye, which comprises the following steps: (1) firstly, adding 50 wt% of water in a container, starting a stirrer for stirring, heating to 30-60 ℃, and then pouring a certain amount of dispersing agent, surfactant and alkali; (2) adding vat dye matrix while stirring, and stirring for 20-30 min; (3) adding water, cooling to 50 deg.C, adding a certain amount of composite reducing agent, stirring for 45min, and adding cold water to 100 wt%; the prepared vat dye is leuco sodium salt dye liquor in a microcolloid state, and the dye liquor still presents a microcolloid state after being diluted by 10 times and 20 times, so that the binding force with fibers is good.

In addition, the invention also provides a one-bath dyeing method adopting the vat dye, which comprises the following steps: putting the object to be dyed which is not pretreated into a dyeing device;

adding the leuco sodium salt dye liquor or the diluent thereof for refining and dyeing.

And after the refining and dyeing, washing with water, soaping and discharging from a vat.

Further, the refining and dyeing step is divided into two steps, wherein the temperature is increased to 60-80 ℃ in the first step, and the temperature is kept for 20-30 minutes; and secondly, heating to 65-90 ℃, supplementing and adding the composite reducing agent and the required accelerating agent according to the requirement, and keeping the temperature for 30-60 minutes. And in the high-temperature refining and dyeing process of the second step, an accelerating agent can be added according to the requirement, so that the fiber dye-uptake rate of the dye is improved, the dye-uptake rate is accelerated, the dye content in the residual liquid is reduced, and a dyeing finished product with higher dyeing depth is obtained, wherein the accelerating agent is at least one of sodium chloride and sodium sulfate. In the high-temperature refining and dyeing process of the second step, the composite reducing agent is supplemented again to control the oxidation-reduction potential of the dyeing solution in a stable range, so that the dyeing effect is ensured.

Furthermore, the temperature rising rate of the first step of the refining and dyeing is 1-3 ℃/min, and the temperature rising rate of the second step is 0.5-1.5 ℃/min.

Further, the material to be dyed without pretreatment is a terylene or nylon or cellulose fiber product.

Further, when the material to be dyed without pretreatment is a terylene or nylon or cellulose fiber product, the bath ratio is 1:10-1: 50.

Further, after the object to be dyed which is not pretreated is placed in the dyeing device, before the dye liquor is added, the method also comprises the step of circularly operating the object to be dyed in the dyeing device, so that the object to be dyed uniformly permeates. When the object to be dyed which is not pretreated is terylene or nylon, the dyeing device can adopt an overflow dyeing machine or a rope dyeing machine, the object to be dyed is added into the dyeing device, and after cold water is added, the rope object to be dyed is circularly operated in the machine under the action of a cloth supporting roller and a nozzle of the dyeing machine, so that the rope object to be dyed is fully soaked. When the objects to be dyed which are not pretreated are cotton loose fibers, the dyeing device can adopt a hanging frame type loose fiber dyeing machine, cold water is added into a cylinder and circulated from the inside to the outside of a central column, and the uniform permeation of the cotton loose fibers at normal temperature is ensured. When the non-pretreated object to be dyed is cotton or other cellulose fiber yarns, the dyeing device can adopt a hanging frame type loose fiber dyeing machine or a cheese dyeing machine, cold water is added into a cylinder, and the cold water is circulated from the inside to the outside of a central column, so that the object to be dyed can be ensured to be uniformly permeated at normal temperature.

Compared with the prior art, the invention has the following beneficial effects:

1) the one-bath dyeable vat dye has stable system and stable chemical potential, and the composite reducing agent in the dye is slowly decomposed, so that the over-reduction reaction with the dye can be reduced.

2) The vat dye leuco dye liquor in a micro-colloid state is prepared by the vat dye matrix, the composite reducing agent, the alkali, the dispersing agent and the surfactant to form a stable reduction system, so that the fabric can be properly pretreated, grease and stains on the surface of the fiber are removed, the gradual permeation and adsorption of the dye are completed, the pretreatment and dyeing are integrated, the energy is saved, the consumption is reduced, and the production efficiency is improved. The novel one-bath dyeable vat dye dyeing method can dye at 60-90 ℃, and the dyed object keeps good color fastness and soft hand feeling.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments will be briefly described as follows:

FIG. 1 is a comparison of the coloration of cotton loose fibers in water after soaking in 95 ℃ hot water for 30 minutes in a finished product dyed by the reduction dyeing method (A) and the reactive dyeing method (B) of the present invention, respectively;

FIG. 2 is a diagram of a finished vat dye dyeing product of a conventional vat dyeing method (using sodium hydrosulfite as a reducing agent);

FIG. 3 is a comparison of a finished product dyed by pad dyeing with a leuco dye liquor (A in the figure) and a finished product dyed by a conventional suspension pad dyeing method (B in the figure) by using the vat dye of the invention;

FIG. 4 is a comparison graph of a high-concentration leuco sodium salt dye solution prepared from the vat dye of the present invention after being diluted 20 times (A in the figure) and a low-concentration normal leuco dye solution (B in the figure) after being dyed respectively;

FIG. 5 is a comparison chart of the dyeing products of pad dyeing process by leuco dyeing method using sodium hydrosulfite and the composite reducing agent of the invention with the same concentration.

Detailed Description

The technical solutions of the present invention are further described in detail below with reference to the drawings and the specific embodiments, but the following examples are only for clearly illustrating the technical solutions of the present invention and are not intended to limit the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the terms used herein in the specification of the present invention are for the purpose of describing particular embodiments only and are not intended to limit the present invention.

Example 1

In this example, four representative dyes are selected from the one-bath dyeable vat dyes of the present invention, and the respective composition is disclosed, which is a standard composition, but of course, some proportions may be adjusted according to specific customer or process requirements. The composite reducing agent is 30-75 wt% of thiourea dioxide, 20-60 wt% of reducing sugar and 5-10 wt% of chemical potential control agent, and the chemical potential control agent is at least one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid, and the following steps are performed. Storage stability tests were carried out on each dye. Since representative indexes embodying the stability of the novel one-bath dyeable vat dye are oxidation-reduction potential and pH value, the two indexes were intensively tested. The novel one-bath dyeable vat dye compositions and the specific test results are shown in tables 1 and 2.

TABLE 1 ingredient Table of novel one-bath dyeable vat dyes

TABLE 2 storage stability (oxidation-reduction potential and pH value) of novel one-bath dyeable vat dyes

As can be seen from the above table, the reduction potential and pH of the leuco dye liquor system of the novel one-bath dyeable vat dye decays slowly during the test period until the desired higher level of the system is maintained after two months; meanwhile, the part with the reduced numerical value can meet the requirement of a specific dyeing process by adding the composite reducing agent and other auxiliary agents during actual use.

Example 2

This example is a comparison experiment of the stability of the reduction potential values of the one-bath dyeable vat dye (using a composite reducing agent) and the vat dye leuco method (using sodium hydrosulfite as a reducing agent) in the same alkaline environment.

The higher the concentration of the mother liquor, the stronger the reducibility thereof. Preparing high-concentration mother liquor of the composite reducing agent and the sodium hydrosulfite with the same concentration, preparing 40g/L of alkali, 50g/L of mother liquor 1 of the composite reducing agent, and preparing 40g/L of alkali and 50g/L of mother liquor 2 of the sodium hydrosulfite.

The two mother liquors were diluted 5-fold and 10-fold respectively, and the variation of the reduction potential values of the mother liquor and the diluted solution was measured and observed. And (3) measuring the reduction potential value of the prepared mother liquor, measuring the reduction potential value of the mother liquor after the mother liquor is diluted by 5 times for 15 minutes, diluting the two mother liquors by 10 times after 5 hours, and measuring the potential values after 30 minutes. The specific components and the measurement results are shown in Table 3.

TABLE 3 two values of mother liquor potential

	Mother liquor 1	Mother liquor diluted by 5 times	Mother liquor 1 diluted 10 times
				Alkali (g/L)	40	8	4
Compound reducing agent (g/L)	50	10	5
				Electric potential (mv)	-975	-914	-821
pH	13.38	13.40	13.19
					Mother liquor 2	Mother liquor 2 diluted 5 times	Mother liquor 2 diluted 10 times
Alkali (g/L)	40	8	4
				Sodium hydrosulfite (g/L)	50	10	5
Electric potential (mv)	-1003	-666	-213
				pH	13.45	13.01	12.82

Through the reducibility comparison experiment of the composite reducing agent and the sodium hydrosulfite with the same concentration, the reduction potential value of the diluted high-concentration mother liquor of the composite reducing agent is not obviously attenuated, the reduction stability is strong, and the dye can be dyed favorably. The sodium hydrosulfite is decomposed too fast, and the reduction potential value is attenuated too fast, so that the dyeing requirement cannot be well met; namely, compared with the conventional leuco dye system which adopts sodium hydrosulfite as a reducing agent, the leuco dye system of the novel one-bath dyeable vat dye has more stable reduction potential value.

Example 3

And (3) carrying out potential stability test on the novel one-bath dyeable vat dye under different concentrations of reducing agent.

Dye solutions of 20g/L, 25g/L, 30g/L, 40g/L and 50g/L composite reducing agents are respectively prepared, and the change of reducibility of the prepared dye solutions is respectively measured at room temperature after the dye solutions are placed for 1 hour and 20 hours under different alkalities. See tables 4 and 5 for details.

TABLE 4 dye liquor standing for 1 hour to determine the value

TABLE 5 dye liquor standing for 20 hours to determine the value

According to data, the composite reducing agent adopted by the one-bath dyeable vat dye solution is stable in a high-concentration area and has small potential fluctuation. The sodium salt state of the leuco body can be stably generated when the alkali concentration is more than 30g/L and the composite reducing agent is more than 20 g/L. The composite reducing agent with the same concentration has the advantages of small change of the reductive potential value and strong stability after being placed for 1 hour and 20 hours in the same alkaline environment. More precise combinations and amounts can be used depending on the properties of the particular dye.

Example 4

In this example, the cotton loose fibers for the colored spun yarns were dyed by the dip dyeing process using the novel one-bath dyeable vat dye of the present invention. The specific process comprises the following steps:

preparing a high-concentration dye solution, which comprises the following specific steps: firstly, adding 50 wt% of water in a container, starting a stirrer for stirring, heating to 30-60 ℃, and then pouring caustic soda, a dispersing agent and a surfactant; adding dye matrix while stirring, and stirring for 20-30 min; adding water, cooling to 50 ℃, adding the composite reducing agent, stirring for 45min, and adding cold water to 100 wt% of the solution for later use. The leuco sodium salt dye liquor is in a microcolloid state. The specific ingredients are shown in table 6, the composite reducing agent is 30-75 wt% of thiourea dioxide, 20-60 wt% of reducing sugar and 5-10 wt% of chemical potential control agent, and the chemical potential control agent is at least one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid; the amount of the dispersant and the surfactant is selected and added between 1-3 wt% and 0-5 wt% of the dye according to the dyeing effect.

TABLE 6 formulation

	3GL yellow	F3B Red	Caustic soda	Composite reducing agent
					Concentration (g/L)	5	60	50	40

And after unpacking the raw cotton, hoisting the loose fibers into a dyeing device, wherein the dyeing device can adopt a hanging frame type loose fiber dyeing machine. Adding cold water into the dyeing machine, circulating for 10-20 minutes from the inside to the outside of the central column, and ensuring uniform permeation at normal temperature.

Diluting the prepared leuco body sodium salt dye liquor mother liquor by 20 times, adding the diluted leuco body sodium salt dye liquor mother liquor into a dyeing machine, and keeping the leuco body sodium salt dye liquor which is diluted by 20 times in a microcolloidal state.

Refining and dyeing are divided into two steps, in the first step, the prepared dye solution is added, the temperature is raised to 60 ℃ at the speed of 1.5 ℃/min, and the temperature is kept for 20-30 minutes; and secondly, heating to 80 ℃ at the speed of 1 ℃/min, adding an accelerating agent sodium chloride or supplementing a proper amount of a composite reducing agent according to needs, and preserving the temperature for 30-40 minutes.

Washing with water for 30min or oxidizing with oxidant, soaping at 85 deg.C for 20 min, washing with cold water, and taking out.

The conventional dyeing of the loose cotton fiber needs desizing and refining of pretreatment, and the dyeing process can be carried out only after the pretreatment solution is discharged from a cylinder body and then the cylinder body is fully washed. In the embodiment, the novel one-bath dyeable vat dye and the auxiliary agent are adopted, so that the optimization of the dip dyeing process of the cotton loose fibers is realized. The novel process combines the pretreatment and dyeing procedures, obviously shortens the process flow, reduces the treatment time and improves the production efficiency.

Because the pretreatment boiling-off and bleaching of the cotton loose fibers are carried out at a high temperature of more than 95 ℃ for a long time, the caustic soda and hydrogen peroxide treatment is too violent, the washing times are more, and the grease and the wax on the cotton fibers are removed too cleanly, so that the hand feel of the dyed cotton fibers becomes hard; meanwhile, the elasticity of the fiber is poor, the length is shortened, and the spinning and weaving process is easy to cause more neps and high end breakage rate. Although the softening agent and the antistatic agent can be added for improvement, the subsequent dyeing and finishing processing difficulty of the fabric is increased. In the process of the embodiment, the pretreatment and the dyeing are combined into one, so that the working procedure time is shortened, the refining and dyeing temperature is controlled below 80 ℃, the damage to the cotton fiber is reduced, and the strength and the hand feeling of the cotton fiber are improved; the fiber strength is protected, and meanwhile, the waste water discharge and the water and electricity consumption are reduced due to the shortening of the working procedure and the proper reduction of the temperature, so that the fiber strength and the fiber strength have obvious energy-saving and consumption-reducing effects.

As shown in fig. 1, a in fig. 1 is a diagram illustrating the effect of the finished product of the cotton loose fiber of the present embodiment after being soaked in 95 degree hot water for 30 minutes. The cotton loose fibers of the embodiment are uniformly colored without a white core phenomenon. The dyed finished product has no decolorization phenomenon after being soaked in hot water at 95 ℃ for 30 minutes. In FIG. 1, B is the dyed product of the cotton fiber dyed by the reactive dyeing method with the same depth of reactive dyeing, and the dyed product has obvious decolorization after being soaked in hot water at 95 ℃ for 30 minutes.

Example 5

The embodiment is a dyeing process of nylon fabrics, and the novel one-bath dyeable vat dye liquor is adopted to dye by a dip dyeing process. In the embodiment, rope dyeing equipment or a normal-pressure overflow dyeing machine is adopted, and the bath ratio is 1:10-1: 50. The specific process comprises the following steps:

preparing a high-concentration dye solution, which comprises the following specific steps: firstly, adding 50 wt% of water in a container, starting a stirrer, heating to 30-60 ℃, and then pouring combined alkali (10-60 wt% of caustic soda, 40-90 wt% of soda ash), a dispersing agent and a surfactant; adding dye matrix while stirring, and stirring for 20-30 min; adding water, cooling to 50 ℃, adding the composite reducing agent, stirring for 45min, and adding cold water to 100 wt% of the solution for later use. The specific ingredients are shown in table 7, the composite reducing agent is 30-75 wt% of thiourea dioxide, 20-60 wt% of reducing sugar and 5-10 wt% of chemical potential control agent, and the chemical potential control agent is at least one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid; the amount of the dispersant and the surfactant is selected and added between 1-3 wt% and 0-5 wt% of the dye according to the dyeing effect.

TABLE 7 formulation

	Vane dye RSN blue	Combined alkali	Composite reducing agent
				Concentration (g/L)	100	60	40

The method comprises the following specific steps:

putting the rope-shaped fabric into a normal-pressure overflow dyeing machine;

cold water is injected into the machine, and the rope-shaped fabric circulates in the machine for 5-15 minutes, namely the rope-shaped fabric circulates in the machine under the action of a cloth supporting roller and a nozzle of a normal-pressure overflow dyeing machine;

diluting the prepared high-concentration dye solution by 20 times, adding the diluted high-concentration dye solution into a dyeing machine, and keeping the diluted leuco body sodium salt dye solution in a microcolloidal state;

refining and dyeing: heating to 60-75 deg.c at 1.5 deg.c/min, maintaining for 20 min, and refining the chemical fiber with oil stain, dust and other impurity at 60-75 deg.c. The combined alkali is consumed while oil stains and other companion substances are gradually removed, the dye liquor gradually diffuses from the surface layer to the core layer, the slow dyeing effect is achieved, and the phenomenon that dyeing is caused by too fast dyeing (nylon is dyed too fast initially, the dyeing saturation value is very low, and the color fastness is poor) is reduced.

Continuously refining and dyeing, heating to 75 ℃ at the speed of 1 ℃/min, adding an accelerating agent or a matched composite reducing agent according to the requirement, and keeping the temperature for 30 minutes. In the treatment process of 60-75 ℃, the composite reducing agent produces refining effect on the nylon fiber under the alkaline condition. The full adsorption and dye-uptake of the leuco sodium salt are simultaneously completed in the refining process.

And discharging liquid after dyeing is finished, washing for two times by cold water for 20 minutes, washing for one time by hot water at 80 ℃, soaping for 15 minutes at 85 ℃, fully washing, and taking out of the vat.

In this embodiment, the rope dyeing machine puts the pretreatment desizing, refining and dyeing processes of nylon into the dyeing solution for synchronous treatment; the existing dip dyeing process is that after the fabric is pretreated in a machine, the pretreated solution is discharged, the pretreated reactant is washed with water, and after the water is drained and cleaned for many times, the dyeing solution is added for dyeing treatment, namely, the two processes of pretreatment and dyeing are divided, and cannot be carried out simultaneously.

The method realizes the combination of the original pretreatment and dyeing procedures into one procedure, completes the adsorption of dyeing while performing the pretreatment, slows down the completion of the dyeing process after the initial dyeing, obviously shortens the process flow, reduces the treatment time and the use of chemical auxiliaries, improves the production efficiency and saves the cost; reduce the friction on the surface of the fiber and improve the cloth cover effect. The temperature of dyeing and pretreatment is reduced from the high temperature of more than 98 ℃ in the prior art to the temperature of less than 80 ℃, and the fiber strength is protected and simultaneously the effects of energy conservation and consumption reduction are obvious.

The dyed product of this example: the dark blue nylon has uniform color, 4-grade dry rubbing fastness and 4-5-grade wet rubbing fastness according to the GB/T3920-2008 standard, and excellent dyeing performance.

Example 6

On the basis of the embodiment 5, the traditional vat dye is changed into the vat dye which uses the sodium hydrosulfite with the same concentration as the reducing agent, the process steps of the embodiment 5 are adopted, the leuco sodium salt dye solution is firstly prepared, the combined alkali is added in the process of heating up cold water, the dye is added under the stirring state at the temperature of below 80 ℃, the sodium hydrosulfite is added after 15 minutes, and the dye solution is changed into the viscous state. In order to improve the contrast effect, the all-cotton semi-finished product which is easier to dye is selected and is thrown into a dye vat according to the embodiment 5, the temperature is raised, the all-cotton fabric is only stained after being taken out of the vat, the dye loses the dyeing ability, as shown in figure 2, the sodium hydrosulfite is used as a reducing agent, the process of the embodiment 5 is adopted, the dyed product is lightly colored, and the effect of combining the original pretreatment and dyeing processes into one process cannot be realized.

Because the conventional reduction dyeing process is limited by the sodium hydrosulfite, the conventional reduction dyeing process cannot normally dye nylon and raw cotton loose fibers. The advantage of excellent light fastness and rinse fastness of the vat dye cannot be exerted.

Example 7

This example is an example of the application of a new one-bath dyeable vat dye liquor to a pad dyeing process.

In this embodiment, a pad dyeing process is performed by using a cotton and linen or rayon woven fabric as an example. A pad dyeing machine is adopted.

The specific process comprises the following steps:

preparing a leuco sodium salt dye solution with high concentration, which comprises the following steps: firstly, adding 50 wt% of water in a container, starting a stirrer, heating to 30-60 ℃, and then pouring caustic soda, a dispersing agent and a surfactant; adding dye matrix while stirring, and stirring for 20-30 min; adding water, cooling to 50 ℃, adding the composite reducing agent, stirring for 45min, and adding cold water to 100 wt% of the solution for later use. The specific ingredients are shown in table 8, the composite reducing agent is 30-75 wt% of thiourea dioxide, 20-60 wt% of reducing sugar and 5-10 wt% of chemical potential control agent, and the chemical potential control agent is at least one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid; the amount of the dispersant and the surfactant is selected and added between 1-3 wt% and 0-5 wt% of the dye according to the dyeing effect, and the following steps are carried out.

TABLE 8 formulation

	Dye VB blue	Caustic soda	Composite reducing agent
				Concentration (g/L)	100	60	60

The method comprises the following specific steps: feeding cloth; padding in a tank added with a penetrant, and then padding in a tank added with a high-concentration leuco sodium salt dye solution diluted by 20 times, ventilating and oxidizing, washing with water, neutralizing with acid, soaping, washing with water, drying and discharging.

The number of the dyeing tanks added with the penetrant can be set to be 1-4, and the temperature is set to be 20-85 ℃. The dyeing tank for adding the leuco sodium salt dye solution can be set to be 1-6, and the temperature can be set to be 30-95 ℃. 1-4 dyeing tanks can be respectively selected and arranged for water washing, acid neutralization and soap boiling, and the temperature can be 20-95 ℃.

In the embodiment, the novel one-bath dyeable vat dye solution disclosed by the invention is adopted, so that the vat dye leuco dyeing method is applied to pad dyeing. As shown in FIG. 3, A in FIG. 3 is an effect chart of the dyed product of the present example, and B in FIG. 3 is an effect chart of the dyed product dyed in suspension with the same concentration of the dyeing liquid. As can be seen from the figure, the finished product dyed by the leuco pad dyeing method of the embodiment is more deeply dyed, so that the cost of the dye for dyeing can be reduced by adopting the leuco pad dyeing method of the embodiment under the condition of dyeing the same depth; aiming at the frock, the women and children dress and the medical fabric, better rinsing fastness can be obtained, and the wearability is improved. The dyeing process is short, the process temperature is reduced, and energy conservation and consumption reduction are realized.

According to GB/T3920-2008, the fastness detection parameters of the dyed product obtained by pad dyeing of the leuco dye and the dyed product obtained by pad dyeing of the suspension are as follows:

TABLE 9 fastness parameters of the dyed products

	Leuco pad dyeing (FIG. 3A)	Pad dyeing of suspension (fig. 3B)
			Colour fastness to dry rubbing	4 stage	4 stage
Color fastness to wet rubbing	Grade 3-4	4 stage

The embodiment adopts the fastness of the finished dyeing product pad-dyed by the novel one-bath dyeable vat dye, wherein the dry rubbing fastness reaches 4 grades, the wet rubbing fastness reaches 3-4 grades, and if the finished dyeing product is dyed with the same depth, the color fastness is higher and the dyeing performance is excellent.

Example 8

FIG. 4 is a graph showing the effect of a pad dyeing process using a novel one-bath dyeable vat dye liquor. Wherein, B is an effect picture of low-concentration 3g/l normal leuco dye liquor after pad dyeing; a is an effect picture of 3g/l dye liquor obtained by diluting the prepared high-concentration leuco sodium salt and then padding the dye liquor. The composite reducing agent and other technological conditions are all carried out in the same state.

The low-concentration 3g/l normal leuco dye liquor is prepared by adopting the following formula:

TABLE 10 Normal dye liquor composition

	Dye indigo	Combined alkali	Composite reducing agent
				Concentration (g/L)	3	3	3

The high-concentration leuco sodium salt is prepared by adopting the following formula:

TABLE 11 composition of the high-strength dyebaths

	Dye indigo	Combined alkali	Composite reducing agent
				Concentration (g/L)	60	60	60

The preparation method of the high-concentration dye solution comprises the following steps: firstly, adding 50 wt% of water in a container, starting a stirrer, heating to 30-60 ℃, and then pouring combined alkali (10-60 wt% of caustic soda, 40-90 wt% of soda ash), a dispersing agent and a surfactant; adding dye matrix while stirring, and stirring for 20-30 min; adding water, cooling to 50 ℃, adding the composite reducing agent, stirring for 45min, and adding cold water to 100 wt% of the solution. After the preparation of the high-concentration dye solution is finished, diluting by 20 times, wherein the concentration of the diluted dye solution and the concentration of the normally prepared low-concentration dye solution are both 3 g/l.

From fig. 4, it can be seen that the dyeing depth of the dyed product obtained by diluting the dye solution prepared by the method for preparing a high-concentration dye solution is obviously much deeper than that of the dyed product obtained by dyeing the dye solution prepared by the normal method and having the same concentration. Because the high-concentration dye liquor still forms a microcolloid state after being diluted by 20 times and has negative ion property, the vat dye is combined with the fiber by Van der Waals force, the binding force is strong, the dyeing property is strong, and the color fastness is high.

As can be seen from Table 12, the leuco sodium salt dye liquor prepared by the preparation method described in the patent has high fastness and excellent dyeing performance after being diluted.

TABLE 12 dyeing fastness parameters

Example 9

FIG. 5 is a comparison chart of dyeing products of pad dyeing process by using novel one-bath dyeable vat dye liquor (composite reducing agent) and a conventional vat dye leuco method (adopting sodium hydrosulfite as a reducing agent). Leuco body mother liquor prepared from the composite reducing agent and sodium hydrosulfite with the same concentration is respectively subjected to pad dyeing after standing for 0.5 hour, 1 hour, 2 hours and 3 hours. As can be seen from FIG. 5, the leuco dye liquor prepared from the novel one-bath dyeable vat dye still keeps good coloring effect for a long time, and the leuco dye liquor of the novel one-bath dyeable vat dye of the embodiment has good stability and excellent dyeing fastness through the pad dyeing process.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.

Claims

1. A novel one-bath dyeable vat dye is characterized by comprising a vat dye matrix, a composite reducing agent, alkali, a high-efficiency dispersing agent and a surfactant.

2. The novel one-bath dyeable vat dye according to claim 1, wherein the vat dye is a complex system formed by reaction and combination of a vat dye matrix, a complex reducing agent, alkali, a high-efficiency dispersing agent and a surfactant, and a to-be-dyed object is directly dyed and fixed in a dye solution prepared from the vat dye matrix, the complex reducing agent, the alkali, the high-efficiency dispersing agent and the surfactant without a long process flow of dyeing-reduction-oxidation fixing of the conventional vat dye suspension dyeing.

3. The novel one-bath dyeable vat dye as claimed in claim 1, wherein the composite reducing agent comprises 30-75 wt% of thiourea dioxide, 20-60 wt% of reducing sugar and 5-10 wt% of chemical potential control agent; the chemical potential control agent is at least one of sodium nitrite, acrylamide, furfural, cyclohexanone and trichloroacetic acid.

4. A novel one-bath dyeable vat dye according to claim 1, wherein said alkali is one or a combination of caustic soda, disodium hydrogen phosphate, soda ash; the dispersant is a product commonly used in the field; the surfactant is selected from surfactants with wetting, penetrating and defoaming effects.

5. A novel one-bath dyeable vat dye according to claim 1, wherein said vat dye further comprises water; 15-35 wt% of vat dye matrix, 5-15 wt% of composite reducing agent, 5-20 wt% of alkali, 1-3 wt% of dispersing agent, 0-5 wt% of surfactant and 30-60 wt% of water.

6. A process for the preparation of the novel one-bath dyeable vat dye of any one of claims 1 to 5, comprising the steps of: (1) firstly, adding 50 wt% of water in a container, starting a stirrer for stirring, heating to 30-60 ℃, and then pouring a certain amount of dispersing agent, surfactant and alkali; (2) adding vat dye matrix while stirring, and stirring for 20-30 min; (3) adding water, cooling to 50 deg.C, adding a certain amount of composite reducing agent, stirring for 45min, and adding cold water to 100 wt%; the prepared vat dye is leuco sodium salt dye liquor in a microcolloid state.

7. A novel one-bath dyeable vat dye dyeing method is characterized by comprising the following steps:

putting the object to be dyed which is not pretreated into a dyeing device;

adding the leuco sodium salt dye liquor or the dilution thereof prepared by the method in claim 6 to carry out the refining dyeing.

8. The method for dyeing by using the novel one-bath dyeable vat dye according to claim 7, wherein the step of the scouring dyeing is divided into two steps, wherein in the first step, the temperature is raised to 60-80 ℃, and the temperature is kept for 20-30 minutes; secondly, heating to 65-90 ℃, supplementing and adding the composite reducing agent and the required accelerating agent according to the requirement, and keeping the temperature for 30-60 minutes; the accelerant is at least one of sodium chloride and sodium sulfate.

9. The method for dyeing with the novel one-bath dyeable vat dye according to claim 8, wherein the temperature rise rate of the first temperature rise is 1 ℃ to 3 ℃/min; the temperature rise rate of the second temperature rise is 0.5-1.5 ℃/min.

10. The method for dyeing by using the novel one-bath dyeable vat dye according to claim 7, wherein the to-be-dyed object without pretreatment is a terylene or nylon or cellulose fiber product.

11. The method for dyeing with the novel one-bath dyeable vat dye according to claim 10, wherein the bath ratio is from 1:10 to 1: 50.

12. The method for dyeing with one-bath dyeable vat dye according to claim 7, wherein after the material to be dyed is put into the dyeing apparatus without pretreatment and before the dye liquor is added, the method further comprises a step of circulating the material to be dyed so that the material to be dyed is uniformly permeated.