CN110172843B

CN110172843B - Cold pad-batch dyeing method for nylon fibers

Info

Publication number: CN110172843B
Application number: CN201910493698.8A
Authority: CN
Inventors: 徐卫林; 夏良君; 王阿明; 周思婕; 付专; 蒋慧敏; 王运利
Original assignee: Wuhan Textile University
Current assignee: Wuhan Textile University
Priority date: 2019-06-06
Filing date: 2019-06-06
Publication date: 2022-02-08
Anticipated expiration: 2039-06-06
Also published as: CN110172843A

Abstract

The invention discloses a cold pad-batch dyeing method of nylon fiber, which comprises the steps of firstly carrying out pre-alkali liquor treatment on the nylon fiber, then dissolving reactive dye in a mixed solvent consisting of a first organic solvent, a second organic solvent and water to prepare a dye solution, carrying out low-temperature pad dyeing treatment, and finally, rolling, stacking, washing and drying to obtain a finished product. The invention achieves the purposes of salt-free, low-alkali and low-temperature dyeing by changing the dyeing process and adopting a reasonable dyeing process, wherein the first organic solvent is preferably tetrachloroethylene or trichloroethylene, the polar solvent has good solubility to the reactive dye, the dip-dyeing temperature can be reduced, the dye-uptake is improved, the dyeing defect is reduced, the dyeing time is greatly shortened, the energy consumption and the pollution to the environment are reduced, and the color fixing rate of the dyed nylon fiber is obviously improved.

Description

Cold pad-batch dyeing method for nylon fibers

Technical Field

The invention belongs to the technical field of textile material printing and dyeing, and particularly relates to a cold pad-batch dyeing method for nylon fibers.

Background

The chemical structure of the nylon fiber is polyamide, the molecular chain contains repeated amide groups, and the chain end contains amino and carboxyl. The nylon fiber has the advantages of good wear resistance, good elasticity, good moisture absorption, light weight and the like, and is commonly used for preparing textile fiber fabrics. When nylon fibers are used as textile fabrics, they are usually dyed with acid dyes, reactive dyes or disperse dyes. Because the content of the terminal amino groups used for dyeing in the nylon fiber is low, only medium-depth color can be obtained by using the acid dye, and the wet fastness is not ideal. Dyeing with disperse dyes is usually carried out at elevated temperatures above 120 ℃ and the wet fastness of the dyed fabrics is not high. The reactive dye has the advantages of complete chromatogram, bright color, good fastness and the like, but because the molecule of the reactive dye contains an anionic group, the reactive dye and negative charges on cotton fibers generate electrostatic repulsion during dyeing, so that the dye uptake and the color fixing rate are low; in addition, in the dyeing process, the reactive dye not only reacts with the fiber, but also reacts with water in a dye bath in a hydrolysis reaction, and the hydrolyzed dye can not react with the fiber basically any more, so that the utilization rate of the dye is reduced, and the dye content in the residual liquid is up to 30-40%. In order to improve the utilization rate of the dye, a large amount of inorganic salt is required to be added in the dyeing process of the reactive dye to overcome the charge repulsion effect, so that the dye uptake rate is improved. The inorganic salt used in a large amount in the printing and dyeing process causes serious environmental pollution, causes the destruction of ecological environment and water resource, makes the soil around rivers and lakes salinized, and the inorganic salt in the wastewater is not easy to treat and can not be biodegraded.

The current approaches to salt-free or low-salt dyeing of reactive dyes include: the method comprises the following steps of development of salt-free and low-salt reactive dyes, fiber modification, application of substitute salt, development of salt-free dyeing auxiliary agents and optimization of dyeing processes.

The dyeing process of nylon 66 knitted fabrics dyed by the reactive dye is researched in the active dye dyed nylon 66 fabric dyeing process discussion, which is published in the journal dye and dyeing, published in 2005, 10, 42, 5 th volume, and the name, although the color yield of the fabrics dyed by the method is higher, the temperature is required to be raised for dyeing at 95 ℃, and the energy consumption is increased.

The patent with the publication number of CN103498348B adopts a method of dyeing a textile to be dyed with alkali liquor in a dye solution formed by mixing a high proportion of alcohol organic solvent, a small amount of water and dye, shortens the dyeing time of reactive dye, realizes salt-free dyeing, and reduces the dosage of alkali agent, but mainly aims at cotton textiles, and needs to be heated for dyeing, and the color fixing rate of reactive dye dyeing is not high enough.

The patent with the publication number of CN103015231B is to dip the textile twice in the accelerating agent solution twice, and then to dye the padded textile in the dye solution mixed by the organic solvent and the water, the method avoids the solid accelerating agent from being dissolved in the organic solvent and separated out in a large amount in the dyeing process, which improves the utilization rate of the dye, but the dyeing process needs to use neutral electrolyte and needs to be heated for dyeing.

The above prior art also has the following disadvantages: (1) the dyeing process needs heating and dyeing, and the energy consumption is high; (2) dyeing auxiliaries such as leveling agents or accelerating agents are required in the dyeing process, so that the dyeing auxiliaries are not beneficial to recycling, and the cost is increased; (3) the fixation of reactive dyes is still not high enough.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a cold pad-batch dyeing method for nylon fibers, which comprises the steps of firstly carrying out pre-alkali liquor treatment on the nylon fibers, then dissolving active dye in a mixed solvent consisting of a first organic solvent, a second organic solvent and water to prepare a dye solution, carrying out pad dyeing treatment at room temperature, and finally carrying out rolling, stacking and washing and drying at room temperature.

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

a cold pad-batch dyeing method of nylon fibers is characterized by comprising the following steps:

s1, preparing alkali liquor: mixing an alkaline agent and water, and uniformly stirring to prepare an alkaline solution with the concentration of 5-30 g/L;

s2, alkaline liquor padding: soaking the nylon fiber to be dyed into the alkali liquor prepared in the step S1, and carrying out padding treatment to prepare the nylon fiber pretreated by the alkali liquor;

s3, preparing a dye solution: respectively weighing a first organic solvent, a second organic solvent and water according to a certain volume ratio, mixing to obtain a mixed solvent, weighing a certain mass of reactive dye, adding the reactive dye into the mixed solvent, and preparing into a dye solution with the concentration of 5-60 g/L;

s4, padding a dye solution: soaking the nylon fiber pretreated by the alkali liquor in the step S2 into the dye liquor prepared in the step S3, and carrying out padding treatment;

s5, rolling and stacking: rolling the nylon fiber padded with the dye liquor in the step S4 on a rolling machine, and then wrapping and stacking; the rotating speed of the rolling machine is 5-10 r/min, the stacking temperature is 25-40 ℃, and the stacking time is 5-24 hours;

s6, washing and drying: and (4) soaping, hot water washing and cold water washing the nylon fiber treated in the step S5 in sequence, and finally drying to obtain a finished product.

Further, in the step S2, the nylon fiber is dipped in alkali liquor at a temperature of 20-35 ℃.

Further, in the step S4, the nylon fiber is dipped in the dye solution at a temperature of 20-35 ℃.

Further, in step S3, the first organic solvent is tetrachloroethylene or trichloroethylene.

Further, in step S3, the second organic solvent is any one of ethanol, ethylene glycol, propylene glycol, isopropanol, acetone, or diethoxyethanol.

Preferably, the second organic solvent is one of ethanol, ethylene glycol or isopropanol.

Further, in step S3, the volume fraction ratio of the first organic solvent, the second organic solvent, and water is 30% to 50%: 45% -55%: 5 to 15 percent.

Further, in steps S2 and S4, the padding is one of one-dipping one-rolling, two-dipping one-rolling, or two-dipping two-rolling.

Preferably, the padding is a two-dip two-pad treatment.

Further, in step S2, the alkali liquor bath ratio is 1: 20-50, the rolling residual ratio is 120% -160%, and the time of each immersion is 3-20 min.

Further, in step S4, the nylon fiber dip-dyeing bath ratio is 1: 10-50, the dip-dyeing time is 3-30 min each time, and the padding rate is 120-160%.

Further, the nylon fiber is one of nylon 6, nylon 66 or nylon 56.

The salt-free high-fixation-rate dyeing method of the reactive dye for nylon fibers provided by the invention is technically characterized in that: the invention achieves the purposes of salt-free, low-alkali and low-temperature dyeing by changing the dyeing process and adopting a reasonable dyeing process. Firstly, carrying out alkali liquor pretreatment on nylon fibers to enable an alkali agent to be adsorbed inside and on the surfaces of the fibers, and then placing the nylon fibers with the alkali liquor into a dye liquor consisting of a first organic solvent, a second organic solvent, a small amount of water and reactive dyes in a high proportion to carry out pad dyeing treatment. According to the adsorption kinetics and thermodynamics of the reactive dye on the nylon fiber, after the nylon fiber carrying the alkali liquor is placed in the dye liquor, the dye liquor formed by the first organic solvent, the second organic solvent and a small amount of water and the reactive dye has very good wettability, so that the dye is transferred to the interior of the fiber within a very short time, and when the dye enters the interior of the fiber, the dye and the end groups of the molecular chain of the fiber are subjected to covalent bonding reaction under the action of the alkali agent and are fixed in the fiber; the fixed dye can cause concentration difference between the inside and the outside of the fiber, so that the dye can be further continuously diffused into the fiber; the continuous dyeing and continuous color fixing cycle greatly shortens the dip dyeing time. In addition, the alkali agent is always adsorbed on the surface of the fiber, so the color fixing efficiency is high, the level dyeing property is good, and the color fixing alkali agent is not needed to be added in the later period, thereby greatly reducing the dosage of the alkali agent. The problems of long dyeing time, difficult dissolution of a color fixing agent in an organic solvent and high dyeing temperature of the traditional dip dyeing process are solved, the dip dyeing time is greatly shortened, and the purposes of salt-free, low-alkali and low-temperature dyeing of nylon fibers are realized.

Advantageous effects

Compared with the prior art, the cold pad-batch dyeing method for the nylon fiber provided by the invention has the following beneficial effects:

(1) the invention carries out pre-alkali liquor treatment on nylon fiber, then dissolves active dye in a mixed solvent consisting of a first organic solvent, a second organic solvent and water to prepare dye liquor, and carries out pad dyeing treatment at normal temperature, thereby realizing the purposes of no salt, low alkali and normal temperature pad dyeing in the dyeing process, greatly shortening dyeing time, reducing energy consumption and pollution to the environment, having the color fixing rate of more than 95 percent and having good dry and wet fastness.

(2) The invention uses the mixed solution of the first organic solvent, the second organic solvent and water with high proportion to dissolve the reactive dye, overcomes the defect of single organic solvent in fiber dyeing, has small surface tension of the organic solvent, can obviously shorten dyeing time, has good level-dyeing property, can be recycled, reduces effective bath ratio and reduces the water consumption.

(3) The first organic solvent is preferably tetrachloroethylene or trichloroethylene, and the polar solvent has good solubility to the reactive dye, can reduce the dip-dyeing temperature, improve the dye uptake and reduce the dyeing defects.

(4) According to the invention, the adsorption capacity of the nylon fiber alkali agent is improved through high alkali liquor residual ratio, so that the covalent bonding reaction efficiency of the reactive dye and the nylon fiber is improved; and the dye liquor residue rate is high, and the padding and the rolling and stacking treatment are carried out, so that the dye uptake and the color fixing rate are further improved.

(5) The dyeing process of the invention does not need to add dyeing auxiliaries such as leveling agent, accelerating agent or penetrating agent, etc., thus reducing the production cost and simplifying the dyeing process.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

A cold pad-batch dyeing method of nylon fibers comprises the following steps:

s2, alkaline liquor padding: soaking the nylon fiber to be dyed into the alkali liquor prepared in the step S1, and carrying out padding treatment to prepare the nylon fiber pretreated by the alkali liquor; the dipping temperature is 20-35 ℃, the dipping time is 3-20 min, the bath ratio is 1: 20-50, and the rolling residual rate is 120-160%;

s3, preparing a dye solution: 30-50% by volume fraction: 45% -55%: 5% -15%, respectively weighing a first organic solvent, a second organic solvent and water, mixing to obtain a mixed solvent, weighing a certain mass of reactive dye, adding the reactive dye into the mixed solvent, and preparing into a dye solution with the concentration of 5-60 g/L;

s4, padding a dye solution: soaking the nylon fiber pretreated by the alkali liquor in the step S2 into the dye liquor prepared in the step S3, and carrying out padding treatment; the dip-dyeing temperature is 20-35 ℃, the bath ratio is 1: 10-50, the dip-dyeing time is 3-30 min each time, and the padding rate is 120-160%;

s5, rolling and stacking: rolling the nylon fiber padded with the dye liquor in the step S4 on a rolling machine, and then wrapping and stacking; the rotating speed of the rolling machine is 5-10 r/min, the stacking temperature is 25-35 ℃, and the stacking time is 5-24 hours;

Example 1

A cold pad-batch dyeing method of nylon 56 fibers comprises the following steps:

s1, preparing alkali liquor: mixing sodium carbonate and water, and stirring uniformly to prepare an alkali liquor with the concentration of 15 g/L;

s2, alkaline liquor padding: soaking the nylon 56 fiber to be dyed into the alkali liquor prepared in the step S1, and performing two-soaking and two-rolling treatment to prepare the nylon 56 fiber pretreated by the alkali liquor; the dipping temperature is 25 ℃, the dipping time is 5min, the bath ratio is 1:40, and the rolling allowance rate is 150%;

s3, preparing a dye solution: according to the volume fraction ratio of 40%: 50%: 10 percent, respectively weighing tetrachloroethylene, ethanol and water, mixing to obtain a mixed solvent, weighing a certain mass of active red 195, adding into the mixed solvent, and preparing into a dye solution with the concentration of 10 g/L;

s4, padding a dye solution: soaking the nylon 56 fiber pretreated by the alkali liquor in the step S2 into the dye liquor prepared in the step S3, and carrying out two-soaking and two-rolling treatment; the dip dyeing temperature is 25 ℃, the bath ratio is 1:20, the dip dyeing time is 5min each time, and the padding rate is 150%;

s5, rolling and stacking: rolling the nylon 56 fiber padded with the dye liquor in the step S4 on a rolling machine, and then wrapping and stacking; the rotating speed of the rolling machine is 5-10 r/min, the stacking temperature is 30 ℃, and the stacking time is 8 hours;

s6, washing and drying: and (4) soaping, hot water washing and cold water washing the nylon 56 fiber treated in the step S5 in sequence, and finally drying to obtain a finished product.

Examples 2 to 8

Examples 2 to 8 are different from example 1 in that the alkali agent, the first organic solvent and the second organic solvent are as shown in table 1, and the others are the same as in example 1.

TABLE 1 alkaline agent, first organic solvent and second organic solvent of examples 2 to 8

Examples	Alkaline agent	A first organic solvent	A second organic solvent
				2	Sodium carbonate	Tetrachloroethylene	Ethylene glycol
3	Sodium carbonate	Tetrachloroethylene	Isopropanol (I-propanol)
				4	Sodium carbonate	Tetrachloroethylene	Diethoxyethanol
5	Sodium carbonate	Trichloroethylene	Ethanol
				6	Sodium hydroxide	Tetrachloroethylene	Ethanol
7	Sodium bicarbonate	Tetrachloroethylene	Ethanol
				8	Sodium bicarbonate	Trichloroethylene	Acetone (II)

Examples 9 to 20

Examples 9 to 20 are different from example 1 in that the conditions for alkali preparation and padding in steps S1 and S2 are as shown in Table 2, and the other steps are the same as example 1.

TABLE 2 examples 9-20 conditions for lye preparation and padding in Steps S1 and S2

Examples	Alkali liquor concentration (g/L)	Of the padding type	Bath ratio	Impregnation temperature (. degree.C.)	Soaking time (min)	Percentage of reduction (%)
							9	5	Two dipping and two rolling	1:40	25	5	150
10	30	Two dipping and two rolling	1:40	25	5	150
							11	15	One dipping and one rolling	1:40	25	5	150
12	15	Two-dipping and one-rolling	1:40	25	5	150
							13	15	Two dipping and two rolling	1:20	25	5	150
14	15	Two dipping and two rolling	1:50	25	5	150
							15	15	Two dipping and two rolling	1:40	20	5	150
16	15	Two dipping and two rolling	1:40	35	5	150
							17	15	Two dipping and two rolling	1:40	25	3	150
18	15	Two dipping and two rolling	1:40	20	20	150
							19	15	Two dipping and two rolling	1:40	20	5	120
20	15	Two dipping and two rolling	1:40	20	5	160

Examples 21 to 26

Examples 21 to 26 are different from example 1 in that the dye liquor preparation conditions in step S3 are as shown in table 3, and the other points are the same as those in example 1.

TABLE 3 preparation conditions of dye liquors of examples 21 to 26

Examples	Volume fraction ratio of solvent	Dye liquor concentration (g/L)
			21	30％:55％:15％	10
22	50％:45％:5％	10
			23	40％:55％:5％	10
24	40％:50％:10％	5
			25	40％:50％:10％	30
26	40％:50％:10％	60

Examples 27 to 32

Examples 27 to 32 are different from example 1 in that the padding bath conditions in step S4 are as shown in table 4, and the other points are the same as in example 1.

TABLE 4 examples 27-32 padding dye liquor conditions

Examples	Of the padding type	Bath ratio	Dip dyeing temperature/. degree.C	Dip dyeing time/min	Percent reduction of rolling mill
						27	One dipping and one rolling	1:20	25	5	150
28	Two-dipping and one-rolling	1:20	25	5	150
						29	Two dipping and two rolling	1:10	35	10	140
30	Two dipping and two rolling	1:30	20	20	130
						31	Two dipping and two rolling	1:50	30	30	120
32	Two dipping and two rolling	1:35	30	3	160
						33	Two dipping and two rolling	1:20	35	3	160

Examples 34 to 37

Examples 34 to 37 are different from example 1 in that the winding and stacking conditions in step S5 are as shown in table 5, and the other points are the same as those in example 1.

TABLE 5 examples 34 to 37 Rolling and piling conditions

Examples	Stacking temperature (. degree. C.)	Stacking time (h)
			34	25	15
35	35	10
			36	30	5
37	30	24

Example 38

Example 38 was compared to example 1, except that the reactive dye was reactive red 120, which was otherwise the same as example 1.

Example 39

Example 39 is compared to example 1 except that the reactive dye is reactive blue 250, which is otherwise the same as example 1.

Example 40

Example 40 is different from example 1 in that the nylon fiber is nylon 6 fiber, and the other is the same as example 1.

EXAMPLE 41

Example 41 is different from example 1 in that the nylon fiber is nylon 66 fiber, and the other is the same as example 1.

Comparative example 1

Comparative example 1 was dyed by one-bath process, which is different from example 1 in that steps S1 and S2 were not included, and in step S3, the ratio of volume fractions was 40%: 50%: 10 percent, preparing a mixed solvent of tetrachloroethylene, ethanol and water, and adding sodium carbonate and activated red 195 into the mixed solvent to prepare a dye solution, wherein the concentration of the sodium carbonate is 15g/L, the concentration of the activated red 195 is 10g/L, and the other conditions are the same as those in the example 1.

Comparative example 2

Comparative example 2 dyeing by post-alkali fixation process, compared with example 1, except that steps S1 and S2 are omitted, after step S4 dyeing, the fiber is dipped in 25 ℃ sodium carbonate solution for two-dip and two-roll treatment, the dipping time is 5min, the sodium carbonate concentration is 15g/L, the bath ratio is 1:40, the rolling residual ratio is 150%, then rolling and stacking are carried out, and the other steps are the same as the examples.

The dyeing effect of the nylon fiber is judged by testing the K/S value and the fixation rate before and after soaping the nylon fibers of the examples 1 to 41 and the comparative examples 1 to 2, and the test results are as follows:

TABLE 6K/S values and fixation ratios of examples 1, 38 to 41 and comparative examples 1 to 2

Sample (I)	K/S before soaping	K/S after soaping	Fixation ratio (%)
				Example 1	18.06	17.80	98.6
Example 38	18.01	17.76	98.2
				Example 39	17.89	17.57	97.9
Example 40	18.02	17.76	98.3
				EXAMPLE 41	18.03	17.75	98.2
Comparative example 1	10.78	9.61	89.1
				Comparative example 2	5.38	5.15	95.7

Table 6 shows the K/S values and the fixation rates before and after soaping in examples 1, 37 to 40, and comparative examples 1 to 2, and it can be seen that the cold pad-batch dyeing method provided by the present invention can realize low-temperature dyeing of nylon fibers 56, 66, and 6 with a plurality of reactive dyes, and the K/S values before and after soaping are all above 17.00, and the fixation rates are all above 97.5%; compared with the comparative example 1, the one-bath dyeing method is adopted, the K/S value is obviously reduced, and the color fixing rate is 89.1%; comparative example 2 adopts post-alkali fixation, the K/S values before and after soaping are lower than 6.00, and the influence of the fixation rate is not large, which shows that the pre-alkali cold pad-batch dyeing method provided by the invention has the best dyeing effect.

TABLE 7K/S values and fixation ratios of examples 2 to 8

Examples	K/S before soaping	K/S after soaping	Fixation ratio (%)
				2	18.01	17.75	98.4
3	17.95	17.72	98.1
				4	17.88	17.68	97.4
5	17.99	17.74	97.8
				6	18.02	17.76	98.0
7	17.85	17.71	97.6
				8	17.81	17.66	97.2

Table 7 shows the K/S values and the color fixing ratios of examples 2 to 8, and it can be seen that when the first organic solvent in the dye solution is tetrachloroethylene and the second organic solvent is an alcohol organic solvent, the dye-uptake effect of the nylon fiber is better, and when the alkaline agent is sodium bicarbonate, the color fixing ratio is slightly reduced. Therefore, sodium carbonate is preferably used as the alkali agent.

TABLE 8K/S values and fixation values for examples 9 to 20

Examples	K/S before soaping	K/S after soaping	Fixation ratio (%)
				9	16.85	15.84	95.2
10	17.83	17.68	97.2
				11	17.26	17.02	96.6
12	17.58	17.32	96.9
				13	17.12	16.86	96.4
14	17.98	17.72	97.3
				15	18.01	17.75	97.4
16	18.03	17.77	97.6
				17	18.02	17.79	97.7
18	18.05	17.82	98.0
				19	17.75	17.51	96.8
20	17.95	17.60	96.9

Table 8 shows the results of the K/S values and the fixation rates of the samples obtained in examples 9-20, and it can be seen that the alkali liquor concentration, the bath ratio and the padding type have a large influence on the dyeing effect of nylon fibers, and that the K/S values and the fixation rates before and after soaping are significantly reduced when the alkali liquor concentration is low, because the alkali liquor adsorption amount of the fibers is reduced and the alkali catalysis effect is weakened when the alkali liquor concentration is low, the fixation rate is reduced; the K/S value and the fixation rate before and after soaping increase with the increase of the alkali liquor concentration and then slightly decrease. When the first dipping and the first rolling are adopted, the K/S value and the fixation rate before and after soaping are also obviously reduced, and the dyeing effect is optimal when the second dipping and the second rolling are adopted, because the dipping and rolling times are properly increased, the alkali liquor absorption capacity of the fiber can be improved, the covalent bond binding capacity of the reactive dye and the hydroxyl on the cellulose is further improved during the dipping and dyeing, and the fixation rate and the K/S value are promoted to be increased. When the concentration of the alkali liquor is the same, the color fixing rate and the K/S value are increased and then reduced along with the increase of the bath ratio, which is probably because the contact efficiency of the fibers and the alkali liquor is reduced when the bath ratio is too low, so that the absorption rate of the alkali liquor is reduced; when the bath ratio is too large, the dyeing effect is slightly poor, and the waste of alkali liquor is caused. The fixation rate and the K/S value change are not large within the range of the impregnation temperature and the impregnation time limited by the invention. When the residue ratio is too high or too low, the improvement of the color fixing rate is not facilitated, probably because when the residue ratio is too low, the alkali adsorption amount of the fiber is reduced, and the catalytic effect is reduced; when the spent rolling rate is too high, the water and the adsorbed alkali amount are too high, so that the hydrolysis of the reactive dye is aggravated, the fiber structure can be damaged to a certain degree, and the fixation rate is reduced.

TABLE 9K/S values and fixation degrees for examples 21 to 26

Examples	K/S before soaping	K/S after soaping	Fixation ratio (%)
				21	17.25	16.89	97.2
22	18.02	17.73	97.6
				23	17.76	17.45	97.5
24	15.85	15.52	96.8
				25	18.01	17.77	97.8
26	18.02	17.78	95.8

Table 9 shows the K/S values and the fixation rates of examples 21-26, and it can be seen that when the water content in the dye liquor increases, the K/S values and the fixation rates decrease, and with the increase of the dye liquor concentration, the fixation rates increase first and then decrease, and the fixation rates are the largest when the dye liquor concentration is 10g/L, because when the fiber is dyed to reach saturation, even if the dye liquor concentration is increased, the dye cannot be combined with the fiber, which results in the decrease of the fixation rates and the waste of the dye.

TABLE 10K/S values and fixation ratios for examples 27 to 37

Examples	K/S before soaping	K/S after soaping	Fixation ratio (%)
				27	16.78	16.52	96.2
28	17.12	16.81	97.1
				29	17.89	17.62	97.8
30	17.45	17.13	97.3
				31	16.66	16.41	96.4
32	17.75	17.43	97.5
				33	17.85	17.61	97.6
34	18.01	17.75	98.1
				35	18.04	17.79	98.3
36	17.89	17.58	97.6
				37	18.05	17.76	98.2

Table 10 results of K/S value and fixation rate tests of examples 27 to 37 show that the dye-uptake effect is the best when padding the dye liquor by adopting two-dip and two-pad, the dye-uptake effect is firstly increased and then decreased with the increase of the bath ratio of the dye liquor, and the fixation rate and the K/S value are the largest when the bath ratio is 1: 20. Within the dip dyeing temperature and the stacking temperature range defined by the invention, the color fixing rate and the K/S value are not changed greatly, the stacking time is prolonged, the dyeing effect is slightly increased, and the stacking time is preferably 8 hours in comprehensive consideration of the dyeing effect and the production efficiency.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A cold pad-batch dyeing method of nylon fibers is characterized by comprising the following steps:

s2, alkaline liquor padding: soaking the nylon fiber to be dyed into the alkali liquor prepared in the step S1, and carrying out padding treatment with the rolling residual rate of 120-160% to obtain the nylon fiber pretreated by the alkali liquor;

s3, preparing a dye solution: 30-50% by volume fraction: 45% -55%: 5% -15%, respectively measuring a first organic solvent, a second organic solvent and water, mixing to obtain a mixed solvent, weighing a certain mass of reactive dye, adding the reactive dye into the mixed solvent, and preparing into a dye solution with the concentration of 5-60 g/L; the first organic solvent is one of tetrachloroethylene or trichloroethylene; the second organic solvent is one of ethanol, ethylene glycol, propylene glycol, isopropanol, acetone or diethoxyethanol;

s4, padding a dye solution: soaking the nylon fiber pretreated by the alkali liquor in the step S2 into the dye liquor prepared in the step S3, and carrying out padding treatment, wherein the padding rate is 120-160%; the dip-dyeing temperature of the nylon fiber in a dyeing solution is 20-35 ℃;

2. The method for cold pad-batch dyeing of nylon fiber according to claim 1, wherein the nylon fiber is dipped in the alkali solution at 20-35 ℃ in step S2.

3. The method of claim 1, wherein in step S1, the alkali agent is one of sodium carbonate, sodium bicarbonate, sodium hydroxide or substituted alkali.

4. The method for cold pad-batch dyeing of nylon fiber according to claim 1, wherein the padding is one of one-dip-one-pad, two-dip-one-pad, or two-dip-two-pad in steps S2 and S4.

5. The cold pad-batch dyeing method for nylon fiber according to claim 1 or 4, wherein in step S2, the alkali bath ratio is 1: 20-50, and each immersion time is 3-20 min.

6. The cold pad-batch dyeing method of nylon fiber according to claim 1, wherein in step S4, the dip-dyeing bath ratio of nylon fiber is 1: 10-50, and each dip-dyeing time is 3-30 min.

7. The method of claim 1, wherein the nylon fiber is one of nylon 6, nylon 66, or nylon 56.