Terylene short-process alkaline dyeing method based on non-aqueous medium system

Abstract

The invention discloses a polyester short-process alkaline dyeing method based on a non-aqueous medium system, and belongs to the technical field of dyeing processes. The method comprises the following steps: (1) mixing a disperse dye and a non-aqueous medium, adding a NaOH aqueous solution, and uniformly mixing to obtain a disperse dye liquor; and (2) putting the polyester fabric into the disperse dye liquor, firstly heating, keeping the temperature for a period of time, then cooling, finally taking out the polyester fabric, soaping, washing with water, and drying to finally obtain the dyed polyester fabric. According to the method, the K / S value of the polyester fabric obtained by keeping the temperature for 30 min under the condition that the NaOH concentration is 2 g / L can reach the K / S value which can be obtained through traditional dyeing processing, and NaOH in the dye liquor has little influence on hydrolysis of disperse dye in a non-aqueous medium system and has a certain alkali decrement effect on the polyester fabric, so that the dyed polyester fabric is better in performance.

Description

Technical Field

[0001] The invention relates to a short-process alkaline dyeing method for polyester based on a non-aqueous medium system, and belongs to the technical field of dyeing technology. Background Art

[0002] The process of dyeing polyester with disperse dyes is currently mostly based on the traditional polyester water bath dyeing method, and its process flow generally includes pretreatment, dyeing, reduction cleaning and finishing of polyester fabrics. Among them, the pretreatment of polyester fabrics and the reduction cleaning after dyeing are both treated in an alkaline environment, while the dyeing step is carried out under weak acid conditions (pH value is 4.5-6), which leads to a process of pH value changing before and after disperse dyeing of polyester. This requires a large amount of acid, water and alkali to adjust the pH value change, resulting in high water consumption, high pollution and high emissions, which has become an important problem restricting the sustainable development of the textile printing and dyeing industry. At the same time, the dyeing in the traditional method is carried out under high temperature and high pressure conditions, and the oligomers inside the polyester fiber will gradually precipitate outward, causing color spots on the surface of the fabric, and combining with the dye to form crystals and adhere to the equipment wall, increasing maintenance costs and reducing heat transfer efficiency. The alkaline dyeing of polyester can solve the above problems very well, so in recent years, the alkaline dyeing of polyester has also become a research hotspot for scholars at home and abroad.

[0003] However, polyester alkaline dyeing requires disperse dyes to have high alkali resistance and high oxidation resistance, and most disperse dyes contain easily hydrolyzed groups such as cyano, ester, and amide groups, and there is a general problem that alkali resistance is not high, and there are fewer varieties of disperse dyes with alkali resistance, incomplete chromatograms, and poor dyeing reproducibility. At the same time, the process of polyester alkaline dyeing is carried out in a water bath system. Because nucleophilic reagents (hydroxyl groups) are evenly distributed in continuous phase water, the easily hydrolyzed sites in the disperse dye structure are easily besieged by nucleophilic reagents in the form of "water-in-oil", and the hydrolysis probability is large, resulting in poor dyeing quality. Therefore, it is necessary to improve the process for polyester alkaline dyeing to provide a novel polyester alkaline dyeing method that is economical, environmentally friendly, and has good dyeing effect.

[0004] Patent CN 107419553 A in the prior art reports a non-aqueous medium dyeing method, which uses reactive dyes to complete dyeing and fixing of cellulose fibers to obtain cellulose fiber dyeing products. However, this technology is a reactive dyeing process containing reactive groups, and the role of the alkali agent in the dyeing system is to provide a suitable pH value for the covalent bond between the reactive groups in the reactive dyes and the cellulose fibers. The disperse dyeing polyester process is completely different from the process reported above, and the role of the alkali agent in the process is also completely different. Therefore, the above report cannot be used to guide the improvement of the disperse dyeing polyester process. Summary of the invention

[0005] [Technical issues]

[0006] At present, the pH value in the pretreatment, dyeing and reduction cleaning processes of the traditional polyester water-bath dyeing method is constantly changing, requiring a large amount of acid, water and alkali to adjust the changes in pH value, resulting in high water consumption, high pollution and high emissions. Although polyester alkaline dyeing can shorten the process flow and reduce pollution, the cyanide, ester and amide groups in disperse dyes are easily hydrolyzed, resulting in poor dyeing reproducibility and poor dyeing quality, which limits the development of polyester alkaline short-process dyeing technology.

[0007] [Technical solution]

[0008] In order to solve the above problems, the present invention utilizes a recyclable non-aqueous medium dyeing system, which can reduce the amount of water used in the whole process on the one hand, and on the other hand, in the non-aqueous medium system, disperse dyes are dispersed in the silicon-based non-aqueous medium in a single molecule dissolved or aggregated state, and the nucleophilic reagent happens to be only dissolved in the aqueous phase that is incompatible with the non-polar medium. The hydrolysis of the disperse dye only occurs at the liquid (non-aqueous medium)-liquid (water) interface, so the probability of the disperse dye's easily hydrolyzed group being attacked will be greatly reduced, and the disperse dye is not easily hydrolyzed, thereby improving the quality of alkaline dyeing. Therefore, based on the non-aqueous medium dyeing system, the present invention utilizes disperse dyes to dye polyester fabrics under alkaline conditions instead of acidic conditions, explores a polyester short-process alkaline dyeing method based on a non-aqueous medium system, and obtains the NaOH concentration and dyeing time when the dyeing quality is optimal under the non-aqueous medium system, and analyzes the hydrolysis mechanism of the alkaline agent NaOH on disperse red dyes and polyester fabrics under both non-aqueous medium and water bath systems.

[0009] The first object of the present invention is to provide a method for short-process polyester alkaline dyeing, the method comprising the following steps:

[0010] (1) mixing disperse dyes and non-aqueous medium, and then adding NaOH aqueous solution to mix evenly to obtain disperse dye dye solution;

[0011] (2) placing the polyester fabric in a disperse dye solution, then heating it up and keeping it warm for a period of time and then cooling it down, and finally taking out the polyester fabric, soaping it, washing it with water, and drying it, to finally obtain the polyester dyed fabric.

[0012] In one embodiment of the present invention, the disperse dyes in step (1) include Disperse Red 73, CI Disperse Red 177, CI Disperse Red 145, CI Disperse Red 179, CI Disperse Yellow 163, and CI Disperse Orange 61.

[0013] In one embodiment of the present invention, the non-aqueous medium in step (1) comprises decamethylcyclopentasiloxane (D5), white oil or liquid paraffin.

[0014] In one embodiment of the present invention, the concentration of disperse dye in the disperse dye solution in step (1) is 0.3-1%, owf.

[0015] In one embodiment of the present invention, the concentration of NaOH in the disperse dye solution in step (1) is 1.75-2.25 g / L.

[0016] In one embodiment of the present invention, the amount of water in the disperse dye liquor in step (1) is 50%, owf.

[0017] In one embodiment of the present invention, owf refers to the weight ratio of material to fabric.

[0018] In one embodiment of the present invention, the polyester fabric in step (2) comprises 100% knitted or woven polyester fabric.

[0019] In one embodiment of the present invention, the bath ratio of the disperse dye solution to the polyester fabric in step (2) is 15 to 30:1.

[0020] In one embodiment of the present invention, the temperature in step (2) is increased to 70-90°C at a rate of 3-10°C / min, and then increased to 120-150°C at a rate of 1-5°C / min.

[0021] In one embodiment of the present invention, the insulation time in step (2) is 25 to 35 minutes.

[0022] In one embodiment of the present invention, the temperature is lowered in step (2) to 70-90°C at a rate of 3-10°C / min.

[0023] In one embodiment of the present invention, the soap washing in step (2) is performed at 90-95° C. for 10-20 min.

[0024] The second object of the present invention is to provide a polyester dyed fabric prepared according to the above method.

[0025] [Beneficial Effects]

[0026] 1. Reduce time and increase efficiency: The present invention uses a non-aqueous medium system to perform alkaline dyeing treatment on polyester fabric. The K / S value of the polyester fabric obtained by keeping warm for 30 minutes at a NaOH concentration of 2g / L can reach the K / S value that can be obtained by traditional dyeing processing, and the NaOH in the dye solution has little effect on the hydrolysis of disperse dyes in the non-aqueous medium system, and has a certain alkali reduction effect on the polyester fabric, so that the dyed polyester fabric has better performance.

[0027] 2. Energy saving and environmental protection: The present invention can greatly reduce the use of water by designing a polyester short-process alkaline dyeing method based on a non-aqueous medium system, and also eliminates the reduction cleaning step in the traditional polyester water bath dyeing method, and directly obtains a polyester dyed fabric with excellent dyeing effect. The entire process consumes less energy and saves resources, and is an energy-saving and environmentally friendly dyeing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The effect of different NaOH concentrations on the K / S value of polyester dyed fabrics in both non-aqueous medium and water bath systems;

[0029] Figure 2 The effect of different NaOH concentrations on the levelness of polyester dyed fabrics in a non-aqueous medium system;

[0030] Figure 3 The effect of different time on K / S value and levelness of polyester dyed fabric under 2g / L NaOH concentration in non-aqueous medium system;

[0031] Figure 4 It is the influence of different conditions on the weight loss rate of polyester fabrics under different dyeing medium systems. DETAILED DESCRIPTION

[0032] Test Method

[0033] 1. Test of K / S value and level dyeing property: Using Datacolor 800 colorimeter, under light source D65, using 10° standard observer, measure four different positions of the sample in the spectral range of 380-700nm to obtain the average value of K / S value. Each sample is measured at nine different points, and then the average K / S value is calculated. The deviation S of the K / S value of each point on the fabric from its average value is used to indicate the level dyeing property of the fabric. The smaller the deviation, the smaller the fluctuation of the data, and the better the level dyeing property of the sample. This is used to evaluate the changes of polyester fabrics after dyeing under different treatment conditions.

[0034] 2. Determination of weight loss rate: In order to determine the weight change of polyester fabric before and after dyeing, the polyester fabric before and after dyeing was weighed after being balanced in a dryer for 24 hours, and the weight loss rate of the polyester fabric was calculated according to the following formula (1).

[0035]

[0036] Where: W0 is the weight of the fabric before dyeing, W1 is the weight of the fabric after dyeing.

[0037] 3. Color fastness to washing with soap: The color fastness to washing with soap of the dyed sample is determined according to the method of GB / T 3921-2008 "Textiles - Color fastness - Color fastness to washing with soap". The textile sample is sewn together with two pieces of standard adjacent fabrics, placed in soap solution, mechanically agitated at 95°C for 30 minutes, and then washed and dried. The original sample is used as a reference sample, and the color change of the sample and the staining of the adjacent fabric are evaluated using a gray sample card or instrument.

[0038] 4. Color fastness to rubbing: The color fastness to rubbing of the dyed sample is measured according to the method of GB / T 3920-2008 "Textiles - Tests for Color Fastness - Color Fastness to Rubbing". The test is carried out using the YS71 dyeing rubbing color fastness instrument produced by Laizhou Yuanmao Instrument Co., Ltd.

[0039] Source of raw materials

[0040] Polyester fabric: 100% polyester woven fabric, specification: 3.5D x 65mm, purchased from Zhejiang Lvyu Textile Co., Ltd.;

[0041] Disperse Red 73: It belongs to disperse dye (filter cake), purchased from Zhejiang Longsheng Dye Chemical Co., Ltd., and its structural formula is as follows:

[0042]

[0043] Example 1

[0044] A new method for short-process alkaline dyeing of polyester in a non-aqueous medium system, the specific steps are as follows:

[0045] (1) Decamethylcyclopentasiloxane (D5) was used as a dyeing medium to prepare a CI Disperse Red 73 dye solution with a dye concentration of 0.5% (owf), wherein the bath ratio was 20:1, and the NaOH concentrations in the dye solution were 0 g / L, 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, and 3.0 g / L, respectively, wherein L was the total volume of the dye solution; the dye solution contained water to dissolve NaOH, and the percentage of water to fabric weight represented the moisture content, which was 50%.

[0046] (2) 1.0 g of polyester fabric was placed in the dye solution, the temperature was raised to 80 °C at a rate of 6 °C / min, then raised from 80 °C to 140 °C at a rate of 3 °C / min, kept at that temperature for 60 min, cooled to 80 °C at a rate of 6 °C / min, and washed with water for 10 min (bath ratio 1:30).

[0047] (3) After washing, the fabric was placed in a 60°C oven and dried for 30 min, and its K / S value and level dyeing properties were tested.

[0048] Example 2

[0049] (1) Disperse Red 73 dye solution with a dye concentration of 0.5% (owf) was prepared with water as the dyeing medium, wherein the bath ratio was 20:1, and the NaOH concentrations in the dye solution were 0 g / L, 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, and 3.0 g / L, respectively, where L was the total volume of the dye solution, and the concentration of the dispersant NNO was 1.0% (owf).

[0050] (2) 1.0 g of polyester fabric was placed in the dye solution, the temperature was raised to 80 °C at a rate of 6 °C / min, then raised from 80 °C to 140 °C at a rate of 3 °C / min, kept at that temperature for 60 min, cooled to 80 °C at a rate of 6 °C / min, and washed with water for 10 min (bath ratio 1:30).

[0051] (3) After washing, the fabric was placed in a 60°C oven and dried for 30 min, and its K / S value was tested.

[0052] The test results of Example 1 and Example 2 are as follows Figure 1 and Figure 2 As shown, from Figure 1 It can be seen that compared with the traditional water medium system in Example 1 and Example 2, at the same alkali agent dosage, the K / S value of the dyed fabric obtained by the non-aqueous medium system using decamethylcyclopentasiloxane as the solvent is higher, and it increases slightly with the increase of the alkali solution concentration, while the K / S value of the dyed fabric in the water bath system decreases sharply. Figure 2 It can be seen that in the non-aqueous medium system, the alkali concentration has little effect on the dyeing levelness of the fabric, and the levelness is less than 0.5, indicating that the dyed fabric has good levelness. At the same time, considering that in order to better remove oligomers in polyester fibers, the alkali concentration is selected to be 2.0g / L.

[0053] Example 3

[0054] (1) Decamethylcyclopentasiloxane (D5) was used as a dyeing medium to prepare a CI Disperse Red 73 dye solution with a dye concentration of 0.5% (owf), wherein the bath ratio was 20:1, the NaOH concentration in the dye solution was 2.0 g / L, wherein L was the total volume of the dye solution; the dye solution contained water to dissolve the NaOH, and the percentage of water to the weight of the fabric represented the moisture content, which was 50%.

[0055] (2) 1.0 g of polyester fabric was placed in the dye solution, the temperature was raised to 80 °C at a rate of 6 °C / min, then raised from 80 °C to 140 °C at a rate of 3 °C / min, the holding time was changed (0, 10, 20, 30, 40, 50, 60, 70, 80, 90 min), the temperature was lowered to 80 °C at a rate of 6 °C / min, and washed with water for 10 min (bath ratio 1:30).

[0056] (3) After washing, the dyed fabrics with different holding times were placed in a 60°C oven and dried for 30 min, and their K / S values, level dyeing properties, and weight loss rates were tested.

[0057] Test Results Figure 3 As shown, it can be seen that the K / S value and levelness of dyed fabrics in non-aqueous medium systems change over time. As the holding time increases from 0 to 30 minutes, the K / S value of the dyed fabric continues to increase, and the levelness continues to improve. This is mainly due to the removal of polyester oligomers and the etching of the polyester surface by the alkali agent during the dyeing process, which reduces the obstacles for disperse dyes to enter the interior of the polyester fiber. At the same time, the etching effect increases the contact area between the dye and the surface of the polyester fiber, increasing the rate at which disperse red 73 enters the interior of the polyester fiber. After the holding time exceeds 30 minutes, the K / S value of the dyed fabric shows a slightly downward trend. This is mainly because the dye undergoes a small amount of hydrolysis after being treated for too long under alkaline conditions. Therefore, 30 minutes is selected as the optimal holding time in the dyeing process.

[0058] Comparative Example 1

[0059] In order to explore the effects of NaOH on the weight loss rate of polyester fabric and the hydrolysis of disperse dyes based on non-aqueous medium system and water bath system, polyester fabric was treated under different dyeing conditions.

[0060] (1) The dyeing conditions are: adding dye in a non-aqueous medium system, not adding dye in a non-aqueous medium system, adding dye in a water bath system, and not adding dye in a water bath system; CI Disperse Red 73 dye solution with a dye concentration of 0.5% (owf) is selected, wherein the bath ratio is 20:1, and the NaOH concentration in the dye solution is 2.0 g / L, wherein L is the total volume of the dye solution; water is contained in the non-aqueous medium system to dissolve NaOH, and the percentage of water to the weight of the fabric represents the moisture content, and the moisture content is 50%; a dispersant NNO is added in the water medium system with a concentration of 1.0% (owf).

[0061] (2) 1.0 g of polyester fabric was placed in the dye solution, the temperature was raised to 80 °C at a rate of 6 °C / min, then raised from 80 °C to 140 °C at a rate of 3 °C / min, kept at this temperature for 30 min, cooled to 80 °C at a rate of 6 °C / min, and washed with water for 10 min (bath ratio 1:30).

[0062] (3) After washing, the fabric was placed in a 60°C oven and dried for 30 minutes, and the weight loss rate of the fabric was tested.

[0063] The weight loss rate test of Example 3 and the test results of Example 4 are as follows: Figure 4As shown, it can be seen that the weight loss rate of polyester fabric in the non-aqueous medium system is higher than that in the water bath system. At the same time, the weight loss rate of polyester fabric with and without dye in the non-aqueous medium system is only 0.36%, indicating that the alkali agent in the dyeing system mainly acts on the hydrolysis of the polyester fabric macromolecular chain. In the case of adding dye in the water bath system, the weight loss rate of polyester fabric is 32.7% lower than that of fabric without dye. This also shows that the water hydrolysis and the hydrolysis of disperse dyes act on polyester at the same time during the water bath dyeing process. Finally, due to the large amount of hydrolysis of disperse dyes in the traditional water bath system, the dyeing depth and quality are greatly reduced. Therefore, the probability of dye hydrolysis in the non-aqueous medium alkaline dyeing system is very small, and the system is suitable for polyester alkaline dyeing. At the same time, after the alkali reduction treatment of polyester fiber, the surface will be uneven, eliminating the aurora of polyester silk fabric, and the luster becomes soft. Therefore, the use of non-aqueous medium system for alkaline dyeing of polyester fabric can achieve the requirements of energy saving and environmental protection, which is in line with the sustainable development of the industry.

[0064] Comparative Example 2

[0065] Compare the effects of non-aqueous medium system and traditional water bath system on color fastness of dyed polyester fabrics.

[0066] (1) a dye solution of CI Disperse Red 73 with a dye concentration of 0.5% (owf) in a non-aqueous medium system, wherein the bath ratio is 20:1, and the NaOH concentration in the dye solution is 2.0 g / L, wherein L is the total volume of the dye solution; water is contained in the non-aqueous medium system to dissolve the NaOH, and the percentage of water to the weight of the fabric represents the moisture content, and the moisture content is 50%;

[0067] The dye concentration of CI Disperse Red 73 in the water bath system is 0.5% (owf), wherein the bath ratio is 20:1, the NaOH concentration in the dye solution is 2.0 g / L, wherein L is the total volume of the dye solution, and the dispersant NNO concentration is 1.0% (owf).

[0068] (2) 1.0 g of polyester fabric was placed in the dye solution, and the temperature was raised to 80 °C at a rate of 6 °C / min, and then raised from 80 °C to 140 °C at a rate of 3 °C / min. The temperature was kept for 30 min in a non-aqueous medium system and for 60 min in a water bath system. The temperature was then lowered to 80 °C at a rate of 6 °C / min and washed with water for 10 min (bath ratio 1:30).

[0069] (3) After washing, the fabric was placed in a 60°C oven and dried for 30 min, and its color fastness to washing and color fastness to rubbing were tested.

[0070] The results are shown in Table 1 below. It can be seen that there is no obvious difference in color fastness to soaping and rubbing between the polyester fabrics obtained after dyeing with the non-aqueous medium system and the aqueous medium system, but the insulation time of the non-aqueous medium system is significantly shortened by half, and the time is shorter. At the same time, no additional dispersant needs to be added during the dyeing process, and the dyeing medium can be reused, which reflects the advantages of the non-aqueous medium system.

[0071] Table 1

[0072]

[0073] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A short-process polyester alkaline dyeing method, characterized in that: The method comprises the following steps: (1) mixing disperse dye and non-aqueous medium, and then adding NaOH aqueous solution to mix evenly to obtain disperse dye dye solution; the concentration of NaOH in the disperse dye dye solution is 1.75-2.25 g / L; (2) placing the polyester fabric in a disperse dye solution, then heating it up and keeping it warm for 25 to 35 minutes and then cooling it down, and finally taking out the polyester fabric, soaping it, washing it with water, and drying it to finally obtain a polyester dyed fabric.

2. The method according to claim 1, characterized in that The disperse dyes in step (1) include CI Disperse Red 73, CI Disperse Red 177, CI Disperse Red 145, CI Disperse Red 179, CI Disperse Yellow 163, and CI Disperse Orange 61.

3. The method according to claim 1, characterized in that In step (1), the non-aqueous medium includes decamethylcyclopentasiloxane, white oil or liquid paraffin.

4. The method according to claim 1, characterized in that The concentration of the disperse dye in the disperse dye solution in step (1) is 0.3-1%, owf.

5. The method according to claim 1, characterized in that The amount of water in the disperse dye liquor in step (1) is 50%, owf.

6. The method according to claim 1, characterized in that In step (2), the bath ratio of the disperse dye solution to the polyester fabric is 15 to 30:

1.

7. The method according to claim 1, characterized in that In step (2), the temperature is increased to 70-90°C at a rate of 3-10°C / min, and then increased to 120-150°C at a rate of 1-5°C / min.

8. The method according to claim 1, characterized in that In step (2), the temperature is lowered to 70-90° C. at a rate of 3-10° C. / min.

9. The method according to claim 1, characterized in that In step (2), soap washing is performed at 90 to 95° C. for 10 to 20 minutes.

10. A dyed polyester fabric prepared according to the method according to any one of claims 1 to 9.

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