Method for dyeing cellulosic fibers by using reactive dye liquid ammonia

Abstract

The invention relates to the technical field of liquid ammonia dyeing, and discloses a method for dyeing cellulose fibers by using reactive dye liquid ammonia. The method comprises the following steps: (1) at-34 DEG C to-75 DEG C, firstly preparing a mixed solution of liquid ammonia and ethyl acetate, and then mixing the mixed solution with a reactive dye to form a dye liquor; (2) putting cellulose fibers into the dye liquor for dyeing; and (3) taking out the dyed cellulose fibers, and carrying out solid-liquid separation and drying. The method is short in process, chemical auxiliaries do not need to be additionally added, the dyeing medium is easy to recycle, and meanwhile the cellulose fibers dyed through the method are high in dye-uptake rate, good in leveling property and high in fixation rate.

Description

Technical Field

[0001] The invention relates to the technical field of liquid ammonia dyeing, and in particular to a method for dyeing cellulose fibers with reactive dye liquid ammonia. Background Art

[0002] Liquid ammonia dyeing is a waterless dyeing technology that uses liquid ammonia as a dyeing medium instead of water as a medium in traditional dyeing. This dyeing technology can shorten the dyeing time, does not require the addition of chemical additives, does not require the dyeing temperature to be regulated, and can simultaneously achieve dyeing and mercerization finishing of cellulose fibers. In addition, liquid ammonia is easy to recycle and reuse. However, there are some technical problems in liquid ammonia dyeing, such as low dye uptake during dyeing, low fixation rate after drying and uneven dyeing. In order to solve these problems, ramie fibers are modified by cationic modification, and then dyed with liquid ammonia to a certain extent, which can improve the dye uptake of active dyes in liquid ammonia dyeing. However, this method requires the fiber to be pre-treated with cationic modification. Therefore, seeking a liquid ammonia dyeing technology that does not require cationic pretreatment to achieve the effect of effectively improving the dye uptake in liquid ammonia dyeing is an important task to promote the industrial production of liquid ammonia dyeing. Summary of the invention

[0003] The purpose of the present invention is to overcome the problems of low dye uptake and fixation rate and poor level dyeing property of liquid ammonia dyed cellulose fibers in the prior art, and to provide a method for dyeing cellulose fibers with liquid ammonia of reactive dyes. The method has a short process, does not require the addition of additional chemical auxiliaries, and the dyeing medium is easy to recycle. At the same time, the cellulose fibers dyed by the method have a high dye uptake, good level dyeing property and a high fixation rate.

[0004] In order to achieve the above object, the present invention provides a method for dyeing cellulose fibers with reactive dyes and liquid ammonia, the method comprising the following steps:

[0005] (1) preparing a mixture of liquid ammonia and ethyl acetate at a temperature of -34°C to -75°C, and then mixing the mixture with a reactive dye to form a dye solution;

[0006] (2) placing the cellulose fibers in the dye solution for dyeing;

[0007] (3) The dyed cellulose fibers are taken out, and then solid-liquid separation and drying are performed.

[0008] Preferably, in step (1), the volume content of ethyl acetate in the mixed solution is 20 to 60%.

[0009] Preferably, in step (1), the volume content of ethyl acetate in the mixed solution is 25-45%.

[0010] Preferably, the weight ratio of the cellulose fiber to the reactive dye is 100:0.1-10.

[0011] Preferably, the ratio of the volume of the mixed solution to the weight of the cellulose fibers is 10-35 mL: 1 g.

[0012] Preferably, in step (1), the reactive dye is selected from one or more of reactive red 195, reactive yellow 145 and reactive blue 194.

[0013] Preferably, in step (2), the cellulose fiber is selected from one or more of ramie fiber, cotton fiber and viscose fiber.

[0014] Preferably, in step (2), the dyeing is carried out under stirring.

[0015] Preferably, in step (2), the dyeing time is 20 to 240 s, preferably 90 to 180 s.

[0016] Preferably, the drying conditions include: a temperature of 80 to 180° C. and a time of 2 to 30 minutes.

[0017] Compared with the prior art, the method for dyeing cellulose fibers with reactive dyes using liquid ammonia of the present invention improves the dyeing rate and fixation rate of cellulose fibers dyed with reactive dyes by adding ethyl acetate to traditional liquid ammonia dyeing, and has good level dyeing properties; and the method has a short process, does not require the addition of additional chemical additives, and the dyeing medium is easy to recycle. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0019] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0020] The present invention provides a method for dyeing cellulose fibers with reactive dye liquid ammonia, the method comprising the following steps:

[0021] (1) preparing a mixture of liquid ammonia and ethyl acetate at a temperature of -34°C to -75°C, and then mixing the mixture with a reactive dye to form a dye solution;

[0022] (2) placing the cellulose fibers in the dye solution for dyeing;

[0023] (3) The dyed cellulose fibers are taken out, and then solid-liquid separation and drying are performed.

[0024] By using the above method to dye cellulose fibers with reactive dyes, the dyeing rate and fixation rate of the cellulose fibers dyed with the reactive dyes can be improved, and the level dyeing property is good. This is mainly because the addition of ethyl acetate accelerates the adsorption of the reactive dye in liquid ammonia by the cellulose fibers, and the desorption of the reactive dye after dyeing is inhibited due to the covering of the cellulose fibers by ethyl acetate, thereby improving the dyeing rate of the reactive dye on the cellulose fibers. After fixation, the cellulose fibers have a high fixation rate and good level dyeing property. In addition, the method has a short process, does not require the addition of additional chemical additives, and the dyeing medium liquid ammonia and ethyl acetate are easy to recycle, which is green and environmentally friendly.

[0025] In a preferred embodiment, in order to improve the dye uptake, fixation rate and level dyeing property of cellulose fibers, in step (1), the volume content of ethyl acetate in the mixed solution is 20-60%; preferably, the volume content of ethyl acetate in the mixed solution is 25-45%; specifically, the volume content of ethyl acetate in the mixed solution can be 25%, 30%, 35%, 40% or 45%.

[0026] In the present invention, the weight ratio of the cellulose fiber to the reactive dye is controlled by the color requirements of the dyed cellulose fiber; in a preferred embodiment, in order to further improve the dyeing rate and levelness of the cellulose fiber, the weight ratio of the cellulose fiber to the reactive dye is 100:0.1-10; preferably, the weight ratio of the cellulose fiber to the reactive dye is 100:1-4.

[0027] In a preferred embodiment, in order to further improve the dye uptake and levelness of the cellulose fibers, the ratio of the volume of the mixed liquid to the weight of the cellulose fibers is 10-35 mL:1 g; preferably, the ratio of the volume of the mixed liquid to the weight of the cellulose fibers is 15-20 mL:1 g.

[0028] In the present invention, there is no special requirement for the reactive dye, and any reactive dye commonly used in the art can be used. In a preferred embodiment, the reactive dye is selected from one or more of reactive red 195, reactive yellow 145 and reactive blue 194.

[0029] In the present invention, there are no special requirements for the cellulose fibers and the form of the cellulose fibers. Any cellulose fiber commonly used in the art can be used. In a preferred embodiment, the cellulose fibers are selected from one or more of ramie fibers, cotton fibers and viscose fibers; specifically, the cellulose fibers can be ramie loose fibers, ramie yarn, cotton yarn or viscose yarn.

[0030] In the present invention, in step (2), the dyeing is carried out at a temperature of -34°C to -75°C; in a preferred embodiment, in order to reduce energy consumption during the dyeing process and reduce the volatilization of liquid ammonia, the dyeing is carried out at a temperature of -34°C to -40°C.

[0031] In a preferred embodiment, in order to improve the level dyeing property of the cellulose fibers, in step (2), the dyeing is carried out under stirring.

[0032] In a preferred embodiment, in order to improve the dye uptake rate of cellulose fibers, in step (2), the dyeing time is 20 to 240 seconds, preferably 90 to 180 seconds.

[0033] In the present invention, in step (3), a centrifugal dehydrator is used to remove the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed cellulose fibers, and then drying is performed. The drying provides energy so that the active dye can react with the cellulose fibers to achieve color fixation.

[0034] In a preferred embodiment, in order to improve the color fixation rate of the cellulose fibers, the drying conditions include: a temperature of 80 to 180° C. and a drying time of 2 to 30 minutes.

[0035] The following examples further illustrate the method for dyeing cellulose fibers with liquid ammonia using reactive dyes of the present invention. The examples are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0036] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0037] Example 1

[0038] (1) at a temperature of -40°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 30%, and then 40 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0039] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 180 seconds;

[0040] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0041] Example 2

[0042] (1) at a temperature of -40°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 30%, and then 40 mL of the mixture is mixed with 0.06 g of reactive blue 194 dye to form a dye solution;

[0043] (2) placing 2 g of cotton yarn in the dye solution at a temperature of -40°C and stirring and dyeing for 90 seconds;

[0044] (3) The dyed cotton yarn is taken out and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed cotton yarn is removed by a centrifugal dehydrator, and then dried at 90°C for 15 minutes.

[0045] Example 3

[0046] (1) at a temperature of -40°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 60%, and then 40 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0047] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 180 seconds;

[0048] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0049] Example 4

[0050] (1) at a temperature of -75°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 20%, and then 40 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0051] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -75°C and stirring and dyeing for 180 seconds;

[0052] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0053] Example 5

[0054] (1) at a temperature of -35°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 30%, and then 60 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0055] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -35°C and stirring and dyeing for 180 seconds;

[0056] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0057] Example 6

[0058] (1) at a temperature of -40°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 10%, and then 40 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0059] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 180 seconds;

[0060] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0061] Example 7

[0062] (1) at a temperature of -40°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 30%, and then 40 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0063] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 10 seconds;

[0064] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0065] Example 8

[0066] (1) at a temperature of -40°C, a mixture of liquid ammonia and ethyl acetate is prepared, wherein the volume content of ethyl acetate in the mixture is 30%, and then 80 mL of the mixture is mixed with 0.06 g of reactive red 195 dye to form a dye solution;

[0067] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 180 seconds;

[0068] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, ethyl acetate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0069] Comparative Example 1

[0070] (1) At a temperature of -40°C, 40 mL of liquid ammonia and 0.06 g of Reactive Red 195 dye were mixed to form a dye solution;

[0071] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 180 seconds;

[0072] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0073] Comparative Example 2

[0074] (1) at a temperature of -40°C, a mixture of liquid ammonia and methyl formate was prepared, wherein the volume content of methyl formate in the mixture was 30%, and then 40 mL of the mixture was mixed with 0.06 g of Reactive Red 195 dye to form a dye solution;

[0075] (2) placing 2 g of ramie loose fiber in the dye solution at a temperature of -40°C and stirring and dyeing for 180 seconds;

[0076] (3) The dyed ramie loose fibers are taken out, and the residual liquid (liquid ammonia, methyl formate and dye) on the dyed ramie loose fibers is removed by a centrifugal dehydrator, and then the fibers are dried at 90° C. for 15 minutes.

[0077] Comparative Example 3

[0078] (1) At a temperature of -40°C, 40 mL of liquid ammonia and 0.06 g of reactive blue 194 dye were mixed to form a dye solution;

[0079] (2) placing 2 g of cotton yarn in the dye solution at a temperature of -40°C and stirring and dyeing for 90 seconds;

[0080] (3) The dyed cotton yarn is taken out, and the residual liquid (liquid ammonia and dye) on the dyed cotton yarn is removed by a centrifugal dehydrator, and then dried at 90°C for 15 minutes.

[0081] Comparative Example 4

[0082] (1) at a temperature of -40°C, a mixture of liquid ammonia and methyl formate is prepared, wherein the volume content of methyl formate in the mixture is 30%, and then 40 mL of the mixture is mixed with 0.06 g of reactive blue 194 dye to form a dye solution;

[0083] (2) placing 2 g of cotton yarn in the dye solution at a temperature of -40°C and stirring and dyeing for 90 seconds;

[0084] (3) The dyed cotton yarn is taken out and the residual liquid (liquid ammonia, methyl formate and dye) on the dyed cotton yarn is removed by a centrifugal dehydrator, and then dried at 90°C for 15 minutes.

[0085] Test Case

[0086] The K / S values ​​of the dyed fabrics of the embodiment and the comparative example were tested, and the level dyeing effect of the fabrics was observed. The results are shown in Table 1.

[0087] Table 1

[0088] serial number K / S value Level dyeing Example 1 9.42 good Example 2 12.64 good Example 3 6.52 good Example 4 6.81 good Example 5 7.43 good Example 6 5.77 good Example 7 6.63 good Example 8 6.26 good Comparative Example 1 4.98 Poor Comparative Example 2 5.21 Poor Comparative Example 3 6.46 Poor Comparative Example 4 7.02 Poor

[0089] It can be seen from the results in Table 1 that dyeing cellulose fibers using the method of the present invention can improve the dye uptake and fixation rate of cellulose fibers, and at the same time, the levelness of dyeing is good.

[0090] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for dyeing cellulose fibers with reactive dye liquid ammonia, characterized in that: The method comprises the following steps: (1) preparing a mixture of liquid ammonia and ethyl acetate at a temperature of -34°C to -75°C, and then mixing the mixture with a reactive dye to form a dye solution; (2) placing the cellulose fibers in the dye solution for dyeing; (3) The dyed cellulose fibers are taken out, and then solid-liquid separation and drying are performed.

2. The method according to claim 1, characterized in that In step (1), the volume content of ethyl acetate in the mixed solution is 20-60%.

3. The method according to claim 1 or 2, characterized in that: In step (1), the volume content of ethyl acetate in the mixed solution is 25-45%.

4. The method according to claim 3, characterized in that The weight ratio of the cellulose fiber to the reactive dye is 100:0.1-10.

5. The method according to claim 1 or 4, characterized in that: The ratio of the volume of the mixed solution to the weight of the cellulose fibers is 10-35 mL: 1 g.

6. The method according to claim 5, characterized in that In step (1), the reactive dye is selected from one or more of reactive red 195, reactive yellow 145 and reactive blue 194.

7. The method according to claim 1 or 6, characterized in that: In step (2), the cellulose fiber is selected from one or more of ramie fiber, cotton fiber and viscose fiber.

8. The method according to claim 7, characterized in that In step (2), the dyeing is carried out under stirring.

9. The method according to claim 1 or 8, characterized in that: In step (2), the dyeing time is 20 to 240 seconds, preferably 90 to 180 seconds.

10. The method according to claim 9, characterized in that The drying conditions include: a temperature of 80 to 180° C. and a time of 2 to 30 minutes.