A water-saving polyester-cotton dyeing process

Abstract

The present invention discloses a water-saving polyester-cotton dyeing process, which dyes polyester-cotton blended fabrics using a non-aqueous medium, employs a disperse accelerating agent with a specific structure, and performs alkali pretreatment on the polyester-cotton blended fabrics, and cooperates with a two-stage heating dyeing process, thereby improving the levelness, dye uptake rate and color depth of the fabrics, reducing the staining of disperse dyes on cotton; in addition, the process flow provided by the present invention is short, greatly reduces water consumption, improves the utilization rate of dyes, and is suitable for industrial application.

Description

Technical Field

[0001] The invention belongs to the field of polyester-cotton printing and dyeing, and in particular relates to a water-saving polyester-cotton dyeing process. Background Art

[0002] Polyester / cotton blended fabrics not only maintain the stiffness and wear resistance of polyester, but also have the moisture absorption and breathability of cotton fabrics, and occupy an important position in the textile market. Polyester / cotton blended fabrics are mostly dyed with disperse dyes and reactive dyes, and the dyeing process is mainly two-bath method and one-bath method. These dyeing processes all use water as the dyeing medium. The main problems are that dyeing is time-consuming, production efficiency is low, water, electricity, steam and other energy consumption is large, and reduction cleaning is required. In addition, a large amount of dispersants, soap detergents, etc. are used, which produces wastewater with high chromaticity values, increasing the difficulty of sewage treatment.

[0003] The world has been developing dyeing processes around the issue of water conservation in printing and dyeing. Among them, organic solvent dyeing technology has attracted widespread attention due to its low equipment requirements, low cost, and high liquid waste recovery rate. At present, the most studied and commercially applied organic solvents are dimethylcyclopentasiloxane (D5) and liquid paraffin. However, the following problems still exist when dyeing polyester or cotton fabrics with disperse dyes or reactive dyes using the above non-aqueous media: the polarity of the non-aqueous medium is low, resulting in low solubility of polar reactive dyes, which causes the dye to quickly dye onto the surface of cotton fibers after cotton is dyed, easily causing color spots and blocks; the solubility of disperse dyes in non-polar media is greater than that in PET, resulting in low dyeing rate of polyester.

[0004] In the prior art, there are many reports on dyeing polyester with disperse dyes in non-aqueous media, and dyeing cotton fibers with reactive dyes in non-aqueous media, but there are few studies on dyeing polyester-cotton blended fabrics in non-aqueous media using a one-bath method. The reason is that disperse dyes easily stain cotton fibers.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a water-saving polyester-cotton dyeing process. The technical scheme is to use non-aqueous medium liquid paraffin as the dispersed phase of the dye solution, dye cotton with reactive dyes, dye polyester with disperse dyes, and complete the dyeing of polyester-cotton with a one-bath and one-step process, thereby greatly reducing water consumption; in addition, the present invention adds a specific auxiliary agent, which has a good dispersing effect on the reactive dye in the low-temperature cotton dyeing stage, enters into the polyester fiber in the high-temperature polyester dyeing stage to swell the polyester fiber, thereby improving the dyeing rate of the disperse dye, and the obtained polyester-cotton blended fabric has a higher color depth.

[0007] The present invention is achieved through the following technical solutions:

[0008] A water-saving polyester-cotton dyeing process, the formula and process are as follows:

[0009] Dye solution formula: reactive dye 1-2% (owf), disperse dye 1-2% (owf), disperse dye accelerator 1-2% (owf), the dispersion medium is decamethylcyclopentasiloxane (D5) or liquid paraffin, and the bath ratio is (1:30) to (1:40).

[0010] Process flow:

[0011] (1) Fabric alkali treatment: The fabric is immersed in an aqueous solution with a temperature of 40-60°C and an alkali concentration of 40-60 g / L, with a bath ratio of 10-20:1, to obtain an alkali-treated fabric with a padding liquid rate of 80% to 120%.

[0012] (2) Reactive dye pretreatment: The reactive dye, dispersing accelerator and non-aqueous medium are mixed in proportion and then ball milled.

[0013] The amount of the active dye and the dispersed dye accelerator is added according to the formula, and the total mass of the active dye and the dispersed dye accelerator, the volume of the non-aqueous medium, and the mass ratio of the zirconium oxide beads are 1g:2-4mL:30g.

[0014] Ball milling conditions: 30-45 Hz, ball milling for 0.5-1 h, using 1-2 mm zirconia beads for ball milling.

[0015] (3) Prepare dye solution.

[0016] (4) Immerse the fabric in a dye bath, raise the temperature to 60-80°C at a rate of 4-6°C / min, keep the temperature for 20-40 min, then raise the temperature to 120-140°C at a rate of 2°C / min, keep the temperature for 30-50 min, and then cool the temperature to 40°C to complete dyeing; rinse with a non-aqueous medium, soap, wash with water, and dry to obtain a dyed fabric.

[0017] The dispersed dye accelerator has the following general formula:

[0018]

[0019] In the formula, R 1 is an alkyl group with 1 to 3 carbon atoms; R 2 , R 3 Selected from H, O(CH 2 ) n CH 3 At least one of the following, wherein n is an integer from 4 to 11.

[0020] In some embodiments of the present invention, the alkali solution is selected from one of sodium carbonate solution, sodium hydroxide solution, and potassium hydroxide solution. The function of the alkali solution is to react with the cotton fiber to deprotonate the hydroxyl group of the cotton fiber and obtain reaction activity.

[0021] In some embodiments of the present invention, the disperse dye can be selected from azo disperse dyes and anthraquinone disperse dyes.

[0022] In some embodiments of the present invention, the reactive dye can be selected from one of triazine type reactive dyes and vinyl sulfone type reactive dyes.

[0023] D5 has a boiling point of about 210℃. It is a colorless, odorless, volatile liquid that is insoluble in water but soluble in most organic solvents. It is a good carrier for dye delivery and heat conduction. Liquid paraffin is mainly a mixture of normal alkanes of C9 to C16. It is transparent, colorless, odorless, and not volatile. It has stable properties and low prices. It has great development potential as a dyeing medium. Using non-aqueous media as the dispersion medium of dyes can reduce water consumption and avoid hydrolysis of active dyes under high temperature alkaline conditions during polyester-cotton one-bath dyeing.

[0024] The present invention performs a pre-alkali treatment on the fabric to improve the polarity of the cotton fiber surface, reduce the adsorption of disperse dyes, and reduce the amount of staining; at the same time, a two-stage heating method is used to dye the reactive dyes at a low temperature stage. As the dyeing rate of the cotton fabric increases, the electrostatic repulsion between the reactive dyes and the disperse dyes avoids the adsorption of the disperse dyes at a subsequent high temperature stage, thereby further reducing the amount of staining.

[0025] The dispersible dyeing accelerator provided by the present invention has a phthalimide structure and a long-chain alkyl structure. On the one hand, the conjugated structure and polarity of the phthalimide can form a II-II stacking effect and a dipole force with the reactive dye, and the non-polarity of the alkyl structure has good compatibility with the dispersion medium, so that the dispersible dyeing accelerator can well disperse the reactive dye, avoid the reactive dye from aggregating and the dyeing rate from being too fast, thereby improving the level dyeing property of the cotton fiber; on the other hand, as the reactive dye is dyed, the dispersible dyeing accelerator that loses the interaction force and is freely dispersed moves to the inside of the polyester fiber at a high temperature, and because the phthalimide structure is similar to polyester and is compatible, the polyester fiber can be plasticized and swollen, thereby facilitating the adsorption and diffusion of the dispersed dye in the polyester fiber and improving the dyeing rate.

[0026] The present invention has the following advantages and beneficial effects:

[0027] The present invention utilizes a non-aqueous medium to dye a polyester-cotton blended fabric, adopts a dispersed dyeing accelerator with a specific structure, performs alkali pretreatment on the polyester-cotton blended fabric, and uses a two-stage heating dyeing process, thereby improving the levelness, dyeing rate and color depth of the fabric, and reducing the staining of disperse dyes on cotton; on the other hand, the process flow provided by the present invention is short, and water consumption is greatly reduced, and the utilization rate of the dye is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 XRD curve of test example 3

[0029] Figure 2 DSC curve of test example 3 DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0031] The raw materials used in the specific implementation are described as follows: dyes were purchased from Zhejiang Longsheng Group Co., Ltd.; polyester-cotton blended fabric (65 / 35), cotton cloth (127.2 g / m 2 , yarn count 40S×40S, yarn density 146×287), polyester (150D×150D) was purchased from Suzhou Fantesi Textile Co., Ltd.; dispersant NNO was purchased from Yunzhe New Materials Technology Co., Ltd.; liquid paraffin was purchased from Zhejiang Tengyu New Materials Technology Co., Ltd.; D5 was purchased from Jiangxi Lanxing Xinghuo Silicone Co., Ltd.

[0032] Example 1

[0033] A water-saving polyester-cotton dyeing process, the formula and process are as follows:

[0034] Dye solution formula: Reactive Red 1952% (owf), Disperse Red 1772% (owf), Disperse Dye Accelerator 2% (owf), Dispersing Medium Liquid Paraffin, Bath Ratio 1:40.

[0035] Process flow:

[0036] (1) Fabric alkali treatment: The fabric was padded in an aqueous solution of sodium carbonate at a temperature of 50°C and a concentration of 50 g / L, with a bath ratio of 20:1, to obtain an alkali-treated fabric with a padding liquid rate of 100%.

[0037] (2) Reactive dye pretreatment: The reactive dye, dispersing accelerator and non-aqueous medium are mixed in proportion and then ball milled.

[0038] The amounts of the active dye and the dispersed dye accelerator are added according to the formula, and the total mass of the active dye and the dispersed dye accelerator, the volume of the non-aqueous medium, and the mass ratio of the zirconium oxide beads are 1g:3mL:30g.

[0039] Ball milling conditions: 40 Hz, ball milling for 0.5 h, using 1-2 mm zirconia beads for ball milling.

[0040] (3) Preparation of dye solution

[0041] (4) The fabric was immersed in the dye bath, heated to 70°C at 5°C / min and kept warm for 30 min, then heated to 130°C at 2°C / min and kept warm for 40 min, and then cooled to 40°C. The dyeing was completed; the fabric was washed with liquid paraffin (60°C, bath ratio 1:40, 15 min), soap washed (Na 2 CO 3 3g / L, soap flakes 3g / L, bath ratio 1:100, temperature 90°C, time 10min), washed with water (60°C, bath ratio 1:100, 20min), washed with water (30°C, bath ratio 1:50, 15min), and dried (80°C) to obtain the dyed fabric.

[0042] The dispersed dye accelerator has the following molecular structure:

[0043]

[0044] Preparation method: weigh 5,6-dihydroxy-2-methylisoindole-1,3-dione, 1-bromooctane, and catalyst tetrabutylammonium bromide into a reactor, add N,N-dimethylformamide (DMF) and stir until the raw materials are completely dissolved, heat to 100°C and react for 10 hours, pour the milky white turbid liquid into water to precipitate to obtain a crude product. Wash with deionized water 5 times to remove tetrabutylammonium bromide and solvent DMF to obtain 5,6-dioctyloxy-2-methylisoindole-1,3-dione. The molar ratio of 5,6-dihydroxy-2-methylisoindole-1,3-dione to 1-bromooctane is 1:2.2, and the mass of tetrabutylammonium bromide is 5% of the mass of 5,6-dihydroxy-2-methylisoindole-1,3-dione.

[0045] 1 H-NMR (400Mz, CDCl 3 ): 0.85(t, 6H, CH 3 ), 1.26~1.42(m,20H,CH 2 ), 1.85 (m, 4H, CH 2 ), 3.14(s, 3H, CH 3 ), 4.22(t,4H,OCH 2 ), 7.54 (s, 2H, Ar-H).

[0046] In Examples 2 to 5, the dispersed dyeing accelerator having the molecular structure in Table 1 is used to replace the dispersed dyeing accelerator in Example 1 to dye the polyester-cotton fabric. The preparation method of Formulas I-2 to I-5 is the same as that of Example 1, except that 5,6-dihydroxy-2-methylisoindole-1,3-dione and 1-bromooctane are replaced by different reactions.

[0047] Table 1

[0048]

[0049]

[0050] Example 6

[0051] The difference from Example 1 is that D5 is used instead of liquid paraffin as the dispersion medium of the dye solution.

[0052] Example 7

[0053] The difference from Example 1 is that the added amount of the dispersed dyeing accelerator is 1% (owf).

[0054] Example 8

[0055] The difference from Example 1 is that the liquid carrying rate in step (1) is 80%.

[0056] Example 9

[0057] The difference from Example 1 is that the liquid carrying rate in step (1) is 120%.

[0058] Example 10

[0059] A water-saving polyester-cotton dyeing process, the formula and process are as follows:

[0060] Dye solution formula: CI Reactive Blue 192% (owf), CI Disperse Blue 3672% (owf), dispersed dye accelerator (I-1) 2% (owf), dispersing medium liquid paraffin, bath ratio is 1:30.

[0061] Process flow:

[0062] (1) Fabric alkali treatment: The fabric was padded in an aqueous solution of sodium carbonate at a temperature of 40°C and a concentration of 60 g / L, with a bath ratio of 20:1, to obtain an alkali-treated fabric with a padding liquid rate of 100%.

[0063] (2) Reactive dye pretreatment: The reactive dye, dispersing accelerator and non-aqueous medium are mixed in proportion and then ball milled.

[0064] The amounts of the active dye and the dispersed dye accelerator are added according to the formula, and the total mass of the active dye and the dispersed dye accelerator, the volume of the non-aqueous medium, and the mass ratio of the zirconium oxide beads are 1g:2mL:30g.

[0065] Ball milling conditions: 40 Hz, ball milling for 0.5 h, using 1-2 mm zirconia beads for ball milling.

[0066] (3) Preparation of dye solution

[0067] (4) The fabric was immersed in the dye bath, heated to 60°C at 4°C / min and kept warm for 40 min, then heated to 140°C at 2°C / min and kept warm for 30 min, then cooled to 40°C, and the dyeing was completed; the fabric was washed with liquid paraffin (60°C, bath ratio 1:40, 15 min), soap washed (Na 2 CO 3 3g / L, soap flakes 3g / L, bath ratio 1:100, temperature 90°C, time 10min), washed with water (60°C, bath ratio 1:100, 20min), washed with water (30°C, bath ratio 1:50, 15min), and dried (80°C) to obtain the dyed fabric.

[0068] Embodiment 11

[0069] A water-saving polyester-cotton dyeing process, the formula and process are as follows:

[0070] Dye solution formula: CI Reactive Yellow 1451% (owf), CI Disperse Yellow 1141% (owf), dispersed dye accelerator (I-1) 1% (owf), dispersing medium liquid paraffin, bath ratio is 1:40.

[0071] Process flow:

[0072] (1) Fabric alkali treatment: The fabric was padded in an aqueous solution of sodium carbonate at a temperature of 60°C and a concentration of 40 g / L, with a bath ratio of 20:1, to obtain an alkali-treated fabric with a padding liquid rate of 100%.

[0073] (2) Reactive dye pretreatment: The reactive dye, dispersing accelerator and non-aqueous medium are mixed in proportion and then ball milled.

[0074] The amounts of the active dye and the dispersed dye accelerator are added according to the formula, and the total mass of the active dye and the dispersed dye accelerator, the volume of the non-aqueous medium, and the mass ratio of the zirconium oxide beads are 1g:4mL:30g.

[0075] Ball milling conditions: 40 Hz, ball milling for 0.5 h, using 1-2 mm zirconia beads for ball milling.

[0076] (3) Preparation of dye solution

[0077] (4) The fabric was immersed in the dye bath, heated to 80°C at 6°C / min and kept warm for 20 min, then heated to 120°C at 2°C / min and kept warm for 50 min, then cooled to 40°C, and the dyeing was completed; the fabric was washed with liquid paraffin (60°C, bath ratio 1:40, 15 min), soap washed (Na 2 CO 33g / L, soap flakes 3g / L, bath ratio 1:100, temperature 90°C, time 10min), washed with water (60°C, bath ratio 1:100, 20min), washed with water (30°C, bath ratio 1:50, 15min), and dried (80°C) to obtain the dyed fabric.

[0078] Comparative Example 1

[0079] The difference from Example 1 is that the dye solution formula is: reactive red 1952% (owf), disperse red 1772% (owf), dispersant NNO 2% (owf), dispersion medium liquid paraffin, and the bath ratio is 1:40.

[0080] Comparative Example 2

[0081] The difference from Example 1 is that the dye solution formula is: Reactive Red 1952% (owf), Disperse Red 1772% (owf), N-methylphthalimide 2% (owf), the dispersion medium is liquid paraffin, and the bath ratio is 1:40.

[0082] Comparative Example 3

[0083] The difference from Example 1 is that the dye solution formula is: reactive red 1952% (owf), disperse red 1772% (owf), N-methylphthalimide 2% (owf), dispersant NNO 2% (owf), dispersion medium liquid paraffin, and the bath ratio is 1:40.

[0084] Comparative Example 4

[0085] Dye solution formula: Reactive Red 1952% (owf), Disperse Red 1772% (owf), Disperse Accelerator 2% (owf), Soda Ash 3% (owf), Water 10% (owf), Dispersing Medium Liquid Paraffin, Bath Ratio is 1:40.

[0086] The process is as follows:

[0087] (1) Reactive dye pretreatment: The reactive dye, dispersible dye accelerator and non-aqueous medium are mixed in proportion and then ball milled.

[0088] The amounts of the active dye and the dispersed dye accelerator are added according to the formula, and the total mass of the active dye and the dispersed dye accelerator, the volume of the non-aqueous medium, and the mass ratio of the zirconium oxide beads are 1g:3mL:30g.

[0089] Ball milling conditions: 40 Hz, ball milling for 0.5 h, using 1-2 mm zirconia beads for ball milling.

[0090] (2) Prepare dye solution: mix disperse dye and dispersion medium.

[0091] (3) The fabric was immersed in a dye bath, heated to 70°C at 5°C / min and kept warm for 30 min, then alkali was added, then heated to 130°C at 2°C / min and kept warm for 40 min, then cooled to 40°C at 5°C / min, soda ash, reactive dyes and water were added, and heated to 60°C at 2°C / min and kept warm for 30 min, then cooled to 40°C to end the dyeing; then washed with liquid paraffin (60°C, bath ratio 1:40, 15 min), soap washed (Na 2 CO 3 3g / L, soap flakes 3g / L, bath ratio 1:100, temperature 90°C, time 10min), washed with water (60°C, bath ratio 1:100, 20min), washed with water (30°C, bath ratio 1:50, 15min), and dried (80°C) to obtain the dyed fabric.

[0092] Test Example 1 Determination of relative staining rate

[0093] The simulated polyester-cotton fabric (mass ratio of polyester to cotton is 65:35) was dyed with disperse dyes, and then the dyed fabric was stripped and the concentration of the stripping solution was measured to calculate the relative staining rate, as follows:

[0094] (1) Prepare disperse dye solutions of different gradients using DMSO, test the absorbance using a UV spectrophotometer, and draw a standard curve corresponding to the concentration and absorbance value.

[0095] (2) Dyeing: First, the cotton is pretreated and then placed in a dye bath together with the polyester. The dye bath formula is: CI Disperse Red 602% (owf), dispersing accelerator, dispersing medium liquid paraffin, and the bath ratio is 1:40; dyeing process: heating to 70°C at 5°C / min and keeping warm for 10 minutes, then heating to 130°C at 2°C / min and keeping warm for 40 minutes, and then cooling to 40°C to complete dyeing; washing twice with liquid paraffin (60°C, bath ratio 1:40, 15 minutes) and drying (80°C, 1 hour) to obtain the dyed fabric.

[0096] (3) Color stripping: The dyed polyester and cotton samples were placed in DMSO at 130°C and boiled for 30 min, with a bath ratio of 1:300. This was repeated twice and the color stripping solutions were combined to obtain the color stripping solutions of polyester and cotton, respectively.

[0097] (4) The absorbance of the stripping solution of the two fabrics was tested by ultraviolet spectrophotometer. The concentration was obtained according to the standard curve. The amount of staining on cotton fabric and the amount of dyeing on polyester were calculated according to the volume of the stripping solution. The relative staining rate = the amount of staining on cotton fabric / the amount of dyeing on polyester.

[0098] Table 2: Relative staining test results

[0099]

[0100]

[0101] As can be seen from the table, the pretreatment process of cotton fabric and the dispersing accelerator have an impact on the relative staining rate of cotton fabric in polyester-cotton fabric. Specifically, on the one hand, the surface polarity of cotton fabric after alkali treatment is enhanced, making it difficult for disperse dyes with lower polarity to adhere to its surface, resulting in a lower amount of staining; on the other hand, the phthalimide structure of the dispersing accelerator is similar to and compatible with the polyester segment of polyester, promoting the swelling of polyester, which is beneficial for the dye to enter the interior of the fiber for recrystallization, thereby improving the dyeing rate and reducing the relative staining rate. Compared with N-methylphthalimide, the dispersing accelerators I-1 and I-5 of the present invention have better dyeing accelerator effects, so the relative staining rate of the resulting fabric is slightly lower. The reason is that after the hydrophobic alkyl group is introduced into the molecule, the similar compatibility of the alkyl group and liquid paraffin promotes the swelling of the dispersed relative fiber. In addition, from the perspective of various variables,

[0102] The higher the temperature, concentration and liquid volume of the sodium carbonate solution, the more favorable it is for the cotton fiber to form a polar environment, resulting in a decrease in the staining rate; the more the amount of dispersed dye accelerator used, the lower the relative staining rate.

[0103] Test Example 2 Level Dyeing Determination

[0104] Cotton fabrics were dyed with non-aqueous medium reactive dyes, and the effect of dispersed dye accelerators on the levelness of cotton fabrics was determined as follows:

[0105] (1) Pretreatment of cotton fabrics;

[0106] (2) mixing the reactive dye and the dispersed dye accelerator by ball milling, the conditions are the same as those in step (2) of Example 1;

[0107] (3) Dyeing of cotton fabric, dye bath formula: reactive red 1952% (owf), dispersed dye accelerator, dispersing medium is liquid paraffin, bath ratio is 1:40; dyeing process: heating to 70°C at 5°C / min and keeping warm for 30min, then heating to 130°C at 2°C / min and keeping warm for 30min, then cooling to 40°C, dyeing is completed; washing with liquid paraffin (60°C, bath ratio 1:40, 15min), soap washing (Na 2 CO 3 3g / L, soap flakes 3g / L, bath ratio 1:100, temperature 90°C, time 10min), washed with water (60°C, bath ratio 1:100, 20min), washed with water (30°C, bath ratio 1:50, 15min), and dried (80°C) to obtain the dyed fabric.

[0108] (4) The apparent color depth K / S value was tested using a Datacolor 650 colorimeter. The D65 light source and 10° viewing angle were selected to measure the K / S value at the maximum absorption wavelength of the dyed fabric. Ten points were randomly selected for each sample and the average value was calculated. The average value is taken as the K / S value of the fabric, and the standard deviation Sr is used to evaluate the levelness of dyeing. The calculation formula of the standard deviation Sr is as follows, n = 10:

[0109]

[0110] Table 3: Levelness test results

[0111]

[0112] From the data in the table, it can be seen that the pretreatment process and the dispersion accelerator have an effect on the levelness of cotton fabrics. Specifically, the ultra-small bath ratio alkaline environment formed by the cotton fabric after alkali treatment provides the reaction conditions between the dye and the fiber, so that the dye adsorbed and dyed can react with the negative ions of the cotton fabric on the fiber surface by covalent bonding, so the pretreatment process has an important influence on the dyeing rate and dyeing rate, and the dyeing rate affects the levelness of the fabric; the dispersion accelerator has an important influence on the dispersibility of the reactive dyes. On the one hand, the reactive dyes are polar and tend to aggregate in non-polar liquid paraffin, resulting in color spots and blocks after dyeing; on the other hand, the polarity difference causes the reactive dyes to be quickly dyed to the surface of the cotton fabric, and the dyeing rate is too fast, resulting in low levelness. The dispersion accelerator provided by the present invention has a good dispersing effect on the reactive dyes, so the obtained cotton fabric has good levelness. The higher the temperature and concentration of the sodium carbonate solution, the more conducive it is for the cotton fiber to form a polar dye bath, resulting in faster dyeing speed and poor level dyeing; although a higher liquid carryover rate is conducive to the formation of a polar dye bath for cotton fibers, resulting in faster dyeing speed and poor level dyeing, at the same time, the dye is better dispersed in the polar phase, which is conducive to level dyeing. Therefore, under the action of these two factors, the level dyeing of the fabric is best at a liquid carryover rate of 100%; the more the dispersing accelerator is used, the better the dispersibility of the reactive dye is, which is more conducive to level dyeing.

[0113] Test Example 3 Plasticity Determination

[0114] The plasticization of polyester fiber by non-aqueous medium containing dispersion promoter is tested as follows:

[0115] (1) Swelling test: The polyester was placed in D5 or liquid paraffin containing a dispersion accelerator at a concentration of 1 wt%, and heat-treated at 130°C for 1 h. After being taken out, it was dried at 80°C for 6 h to obtain a sample.

[0116] (2) Plasticity was evaluated from the following dimensions: ① Swelling degree: A NiKon E200 optical microscope was used to observe and measure the diameter of the fiber before and after swelling. Ten fibers were selected for each group of samples, and 10 test sections were selected for each fiber. Each test section was measured 10 times, and then the average diameter of a certain sample was calculated, swelling degree = (average diameter of the fiber after swelling - average diameter of the untreated fiber) / average diameter of the untreated fiber; ② DSC: A NETZSCH 204C differential scanning calorimeter was used to measure the glass transition temperature Tg of the fiber before and after swelling, with a heating rate of 10°C / min and a nitrogen atmosphere; ③ XRD: An X′Pert3 Powder X-ray diffractometer was used to determine the crystallinity of the fiber, with a test voltage of 40 kV, a scanning speed of 10° / min, and a test range of 10 to 50°.

[0117] The results of swelling degree and glass transition temperature Tg are listed in Table 4, and the DSC curve and XRD curve are shown in the attached Figure 1 and 2 .

[0118] Table 4: Plasticity test results

[0119]

[0120] From the data in the table, it can be seen that the Tg of polyester fibers treated with D5 or liquid paraffin solution containing a dispersing dye accelerator is reduced, indicating that the solution has a plasticizing effect on the fiber, and the increased mobility of the fiber macromolecular chain segments increases the loose and unfixed area of ​​the fiber structure, which increases the diffusion capacity of the dye in the fiber, accelerates the dyeing rate and increases the dyeing rate. From the perspective of various variables, the more alkyl segments there are and the longer they are, the stronger the plasticizing and swelling effect on the fiber is. This is because the alkyl segments are similarly soluble in liquid paraffin, so they act as a bridge to promote the plasticization of the liquid paraffin on the fiber.

[0121] from Figure 2 From the above, the untreated polyester fiber has characteristic diffraction peaks at 2θ=17.5°, 22.6° and 25.4°, and the positions of the diffraction peaks correspond to the three polyester fiber diffraction crystal planes (010), (110) and (100). The polyester fiber swelled in the liquid paraffin solution containing the dispersing accelerator also has characteristic diffraction peaks at the above three positions, indicating that the medium treatment has not affected the crystal structure of the polyester fiber.

[0122] Test Example 4 K / S value determination

[0123] The apparent color depth K / S value of the blended fabrics obtained in the examples and comparative examples was tested using a Datacolor 650 colorimeter. The D65 light source and 10° viewing angle were selected to measure the K / S value at the maximum absorption wavelength of the dyed fabric. Ten points were randomly selected for each sample for measurement, and then the average value was calculated.

[0124] Test Example 5: Color fastness test

[0125] Test the color fastness of dyed fabrics to washing with soap according to GB / T 3921-2008 "Textiles - Tests for color fastness - Color fastness to washing with soap";

[0126] Test the color fastness to rubbing of dyed fabrics according to GB / T 3920-2008 "Textiles - Tests for color fastness - Color fastness to rubbing";

[0127] The color fastness of dyes to sunlight is tested in accordance with GB / T 8427-2008 Textiles - Tests for color fastness to artificial light: Xenon arc fading lamp.

[0128] Table 5: K / S value and color fastness test results

[0129]

[0130]

[0131] The above contents are further detailed descriptions of the present invention in combination with specific preferred technical solutions, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For professionals and technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A water-saving polyester-cotton dyeing process, characterized in that: The following steps are involved: (1) Alkali treatment of polyester-cotton blended fabric: The polyester-cotton blended fabric is immersed in an alkali solution to obtain an alkali-treated fabric; (2) preparing a dye solution: firstly, mixing a reactive dye, a disperse dye accelerator and a portion of a non-aqueous medium in proportion and then ball milling to obtain a mixture; then mixing with a disperse dye and the remaining non-aqueous medium to obtain a dye solution; the non-aqueous medium is decamethylcyclopentasiloxane D5 or liquid paraffin; The dispersed dye accelerator has the following molecular structure: In the formula, R1 is an alkyl group with 1 to 3 carbon atoms; R2 is H or O(CH2) n CH3, wherein n is an integer from 4 to 11; R3 is O(CH2) n CH3, wherein n is an integer from 4 to 11; (3) Immerse the fabric in the dye bath, heat it to 60-80°C and keep it warm for 20-40 minutes, then heat it to 120-140°C and keep it warm for 30-50 minutes, then cool it down to 40°C, and the dyeing is completed; The dyed fabric is obtained after non-aqueous medium rinsing, soaping, water washing and drying.

2. A water-saving polyester-cotton dyeing process according to claim 1, characterized in that: The alkali solution described in step (1) is selected from one of sodium carbonate solution, sodium hydroxide solution and potassium hydroxide solution.

3. A water-saving polyester-cotton dyeing process according to claim 1 or 2, characterized in that: The concentration of the alkali solution in step (1) is 40-60 g / L.

4. A water-saving polyester-cotton dyeing process according to claim 3, characterized in that: The temperature of the alkali solution is 40-60°C.

5. A water-saving polyester-cotton dyeing process according to claim 1 or 4, characterized in that: The liquid carrying rate of the padding is 80% to 120%.

6. A water-saving polyester-cotton dyeing process according to claim 1, characterized in that: The ball milling conditions in step (2) are: a frequency of 30 to 45 Hz, a ball milling time of 0.5 to 1 h, and 1 to 2 mm zirconia beads are used for ball milling.

7. A water-saving polyester-cotton dyeing process according to claim 6, characterized in that: In step (2), the total mass of the reactive dye and the dispersed dye accelerator, the volume of the non-aqueous medium, and the mass ratio of the zirconium oxide beads are 1 g: 2-4 mL: 30 g.

8. The water-saving polyester-cotton dyeing process according to claim 1, characterized in that: The dye solution formula is: 1-2% owf of reactive dye, 1-2% owf of disperse dye, 1-2% owf of disperse dye accelerator, and the bath ratio is (1:30)-(1:40).

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