An improved dyeing process for reactive dyeing of all-cotton knitted fabrics with short wet steaming

Abstract

The present invention provides an improved short wet steaming dyeing process for reactive dyes on all-cotton knitted fabrics, which is characterized in that the steps include: S1, padding the dye liquor and auxiliaries; S2, quickly drying with a drying cylinder, adding a double-row drying cylinder and a temperature and humidity detection system, and installing a C-type steam adjustable heating device on the outer layer of the drying cylinder to control the final liquor pickup of the dyed fabric at 30±5%; S3, quickly steaming; S4, cold water washing, washing at room temperature through 2 water washing tanks; S5, hot water washing; S6, soaping; S7, high-temperature water washing; S8, acid washing. It solves the curling phenomenon of knitted fabrics, reduces the liquor pickup of the fabric surface, reduces steam consumption, controls the pre-drying degree of both sides of the fabric surface, reduces the dye migration during the dyeing process of knitted fabrics, alleviates dye hydrolysis, and improves the dye uptake rate and fixation rate.

Description

Technical Field

[0001] The present invention relates to the technical field of cotton fabric dyeing, and particularly relates to an improved dyeing process for short wet steaming of reactive dyes on all-cotton knitted fabrics. Background Art

[0002] The wet steaming process has the advantages of short process flow, good reproducibility, bright color, saving of dyes and chemicals, and less environmental pollution. Researchers found at the initial stage of R & D that after the fabric was impregnated with the dye liquor and then directly wet steamed without pre-drying, there was no dye migration caused by pre-drying, and the color of the dyed fabric was uniform. However, during wet steaming, the fixation degree of reactive dyes was significantly limited, and the loss of dyes was as high as 30 - 50% [See: Yu Chengbing, Tao Kaixin, Hou Qi'ao, etc. Optimization of wet steaming dyeing process for cotton knitted fabrics by response surface central composite design method [J]. Advanced Textile Technology, 2019, 27(03): 73 - 77; Li Ke, Xu Zhizhong, Feng Haijian. Reactive dye wet short steaming dyeing of pure cotton fabrics [J]. Dyeing & Finishing, 2016, 42(20): 24 - 27.]. Based on this, improvements were made. An electric infrared heater installed at the entrance of the reaction box was used to heat the wet fabric impregnated with the dye liquor, so that the fabric was quickly heated and dehumidified. The heat carrier in the reaction steaming box with a temperature and humidity monitoring device was a mixed gas of dry hot air and a small amount of steam. The steam content of the circulating air in the hot air was monitored by a dry and wet bulb thermometer to adjust the reaction temperature (dry bulb) and relative humidity. This process was simple, efficient, energy-saving and easy to control, with a high fixation rate, and had the advantages of sufficient penetration, uniform and bright color, etc. [Xie Yongxin, Gao Zhaochang, Li Liang. Wet short steaming process of reactive dyes [J]. Light and Textile Industry and Technology, 2012, 41(02): 6 - 7. Lv Chuanyou, Chen Koufu, Chen Yuan. Transformation of the old machine's reactive wet short steaming process [J]. Dyeing & Finishing, 2002(10): 29 - 30, 54.]. Now, the heat carrier used in the wet steaming dyeing process is a large amount of dry hot air infiltrating a small amount of saturated steam. When the saturated steam is mixed with the dry hot air, it adiabatically expands. For the saturated steam, the temperature increases while the pressure decreases. Therefore, the mixed heat carrier is unsaturated superheated steam, which is beneficial to fabric drying. It not only provides heat, but also forms a dynamic balance with the evaporation of the moisture on the fabric during condensation on the fabric. The vapor-phase steam condenses on the fabric, easily penetrates the fabric, makes the fabric fully expand, helps the dye molecules occupy the appropriate positions in the cellulose macromolecules, and reacts with the cellulose hydroxyl groups, which is beneficial to the fixation of the dyes [Shu Dawu. Reactive dye wet short steaming dyeing of cellulose fabrics based on atmospheric pressure saturated steam medium [D]. Tianjin Polytechnic University, 2019.].

[0003] Chinese Patent CN215713975U, a new type of short - process dyeing machine wet - steaming and color - fixing device, completes the wet - steaming of fabrics by setting up a wet - steaming mechanism, enabling the upper and lower end faces of the fabric to contact high - temperature steam simultaneously, improving the heating efficiency of the fabric. By setting up a rotating mechanism to drive the steam pipe to rotate, it effectively avoids the situation of excessive local heating of the fabric, further makes the fabric heat evenly, and improves the color - fixing rate.

[0004] Chinese Patent CN208104767U, a high - elastic warp - knitted fabric wet - short - steaming dyeing device, can press the fabric tightly through connecting rods, pressing rods, connecting columns and springs. By cooperating with the loading plate, the first motor, the driving rod, the driving column, the first mounting plate and the pressing plate, it can press the fabric periodically. When pressing, the solution in the fabric precipitates, and when released, the solution enters the fabric. The periodic reciprocating pressing makes the fabric dye evenly and has good quality.

[0005] Chinese Patent CN114855475A, a cotton / nylon / lyocell fabric reactive dye wet - short - steaming clean pad - dyeing process, adopts two - dip two - pad, which can shorten the dyeing process of the three - component cotton / nylon / lyocell fabric, reduce migration and time consumption, reduce costs and chemical consumption, save energy consumption, reduce pollution, reduce energy consumption and carbon emissions, and has good penetration and levelness, high color yield and color fastness.

[0006] Compared with the rope - dyeing process, the existing short - wet - steaming process has greatly reduced energy consumption, but there is still room for improvement. Especially, the high liquor - pick - up rate of the fabric before steam - heating will accelerate the hydrolysis of dyes, and more steam is required for heating. At the same time, the knitted fabric in pad - dyeing will have serious curling under the action of tension. Summary of the Invention

[0007] Aiming at the problems of curling of knitted fabrics, hydrolysis of dyes, energy consumption, etc. existing in the existing short - wet - steaming technology, a wet - short - steaming dyeing process for knitted fabrics is proposed. On the basis of the general short - wet - steaming process, a drying cylinder drying part is installed before steam - heating after padding the dye. The knitted fabric will curl under the action of tension, and the presence of the drying cylinder makes the fabric fit the drying cylinder and move forward, reducing the curling phenomenon. A temperature and humidity detection device is installed in the drying cylinder drying part to accurately detect the liquor - pick - up rate and temperature of the fabric surface, and maintain the final liquor - pick - up rate of the fabric surface at 30±5%, reducing the hydrolysis of dyes during steam - heating and color - fixing. The drying cylinder is improved, and a C - type steam adjustable heating device is installed on the outer layer to adjust the water evaporation rate on both sides of the fabric surface to be the same, which can avoid the migration phenomenon while ensuring the dye uptake rate. At the same time, the lower liquor - pick - up rate saves energy for the subsequent steam - heating process, and the less water content weakens the heat loss, reducing the time and energy consumption of steam - heating.

[0008] By adding a double-row drying cylinder and a temperature and humidity detection system before steam heating, the drying cylinder is improved. A C-type steam adjustable heating device is installed on the outer layer to solve the curling phenomenon of knitted fabrics, reduce the liquid-carrying rate of the cloth surface, reduce steam consumption, control the pre-drying degree of both sides of the cloth surface, reduce the dye migration during the dyeing process of knitted fabrics, alleviate dye hydrolysis, and improve the dye uptake rate and fixation rate. Through single-factor variable experiments, this patent improves process conditions such as the dosage of salt and alkali, the temperature of the drying cylinder, the liquid-carrying rate, and the steam heating time, and improves the dye uptake rate and fixation rate while solving the above-mentioned disadvantages.

[0009] The present invention provides an improved short wet steaming dyeing process for all-cotton knitted fabrics with reactive dyes, which is characterized in that the steps include: S1, padding the dye liquor and auxiliaries; S2, quickly drying with a drying cylinder, adding a double-row drying cylinder and a temperature and humidity detection system, installing a C-type steam adjustable heating device on the outer layer of the drying cylinder, with a temperature of 50-100 °C, so that the final liquid-carrying rate of the dyed cloth is controlled at 30±5%; S3, quickly steam heating; S4, cold water washing, washing at room temperature, passing through 2 water washing tanks; S5, hot water washing; S6, soaping; S7, high-temperature water washing; S8, acid washing.

[0010] Further, in step S1, the dye liquor includes: 0-70 g / L of dye, 1.0-5.0 g / L of penetrant, 1.0-5.0 g / L of anti-migration agent; the formula of the auxiliaries includes: 20-40 g / L of soda ash, 20-60 g / L of sodium sulfate; the liquor ratio is 70-80%.

[0011] The drying cylinder is a steam drying cylinder in a dyeing factory, and its surface is treated with Teflon to prevent color staining.

[0012] Further, in step S3, saturated steam is used for quick steam heating, wherein the temperature of the steaming box is 102 °C and the steam heating time is 1-2 min.

[0013] Further, S4, cold water washing, washing at room temperature, passing through 2 water washing tanks; S5, hot water washing, washing with 80 °C hot water, passing through 1 water washing tank; S6, soaping, using soap liquor, soaping at 98 °C, passing through 1 soaping tank; S7, high-temperature water washing, the water washing temperature is 80 °C, passing through 1 water washing tank; then rinsing with warm water, passing through 1 water washing tank; S8, acid washing, using 1 g / L acetic acid solution, acid washing at room temperature, passing through 1 acid washing tank, and then rinsing with normal temperature clear water, passing through 1 water washing tank.

[0014] The beneficial effects of the present invention:

[0015] (1) Adjust the traditional short wet steaming process, add a double-row drying cylinder step and temperature and humidity detection before steam heating, improve the drying cylinder, install a C-type steam adjustable heating device on the outer layer, while reducing dye migration, solve the curling problem of knitted fabrics;

[0016] (2) Use the improved drying cylinder to adjust the liquid content rate of the fabric before steaming to 30±5%, and adjust the moisture evaporation rate on both sides of the fabric to be consistent. On the one hand, it reduces the hydrolysis of dyes during the steaming and fixation process, improves the dye uptake rate, and on the other hand, it saves the steaming time and energy consumption.

[0017] (3) Adjust the dyeing process conditions such as the amount of salt and alkali used in pad dyeing, the steaming temperature, and the time.

[0018] Through small sample simulation tests, after adopting the process of this patent in the present invention, the fabric is evenly dyed, no obvious migration phenomenon appears, the dye uptake rate is significantly improved, the curling phenomenon is greatly reduced, the dyeing time is shortened, and the energy consumption in dyeing is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of a short wet steaming dyeing device (ordinary drying cylinder) for knitted fabric reactive dyes.

[0021] Figure 2 It is a schematic diagram of the short wet steaming dyeing device for knitted fabric reactive dyes of the present invention.

[0022] Figure 3 Shown are qualified products with basically no shrinkage and curling (Longsheng reactive navy C-2GLN, front (left), back (right)).

[0023] Figure 4 Shown are unqualified products with slight shrinkage and curling and serious color difference between the front and back (Longsheng reactive navy C-2GLN, front (left), back (right)).

[0024] Figure 5 Shown are unqualified products with serious shrinkage and curling and serious color difference between the front and back (Longsheng reactive navy C-2GLN, front (left), back (right)).

[0025] In the figure: ① Dyeing trough; ② Dye vat; ③ Auxiliary agent vat; ④ Dyeing trough fabric guide roller; ⑤ Drying chamber fabric guide roller;

[0026] ⑥ Drying cylinder; ⑦ Fan; ⑧ Drying chamber; ⑨ Unidirectional moisture exhaust pipe; ⑩ Steaming chamber fabric guide mesh roller; Steaming chamber;

[0027] Steamer; Fabric delivery roller; Protective cover (with cloth surface temperature and humidity detector); C-type steam drying cylinder. Specific implementation manner

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment 1

[0030] An improved short wet steaming dyeing process for reactive dyes of all-cotton knitted fabrics, characterized in that it includes the following processes: S1. Padding the dye liquor, the dyeing bath is 50L, the padding temperature is 20°C, and the liquor pickup rate is 70%. A high liquor supply device is used to supply dyes and auxiliaries. The formula of the dye liquor includes: 10g / L of Longsheng reactive navy blue C-2GLN dye, 2.0g / L of penetrant, and 2.0g / L of anti-migration agent; the formula of the auxiliaries includes: 40g / L of soda ash and 30g / L of sodium sulfate; S2. Quick drying with a drying cylinder, using the drying cylinder of the present invention, with a C-type steam adjustable heating device installed on the outer layer (as Figure 2 shown), the temperature and speed of the drying cylinder are adjusted by a temperature and humidity detection device, the temperature of the drying cylinder is 90°C, and the final liquor content of the dyed cloth is controlled at 30±5%; S3. Quick steam steaming, using saturated steam for quick steam steaming, wherein the temperature of the steaming box is 102°C and the steam steaming time is 2min (120s); S4. Cold water washing, washing at room temperature, passing through 2 water washing tanks; S5. Hot water washing, washing with 80°C hot water, passing through 1 water washing tank; S6. Soaping, using soaping liquor, soaping at 98°C, passing through 1 soaping tank; S7. High-temperature water washing, the water washing temperature is 80°C, passing through 1 water washing tank; then rinsing with warm water, passing through 1 water washing tank; S8. Acid washing, using 1g / L acetic acid solution, acid washing at room temperature, passing through 1 acid washing tank, and then rinsing with normal temperature clear water, passing through 1 water washing tank.

[0031] Under the dyeing conditions of Embodiment 1, the dosages of sodium sulfate and soda ash, the temperature of the drying cylinder, the liquor content after drying, and the steam steaming time were respectively adjusted to obtain the test results of the following Embodiments 1-6 and Comparative Examples 1-2, as shown in Table 1.

[0032] The front and back color difference, edge-to-edge color difference, K / S value, and fixation rate are tested according to the standard test methods in the art. The shrinkage and curling situation is visually evaluated by technicians. As shown in the appendix Figure 3 is a qualified product with basically no shrinkage and curling. The appendix Figure 4 is an unqualified product with slight shrinkage and curling but serious front and back color difference of the cloth. The appendix Figure 5It is a non-conforming product with serious shrinkage and curling of the edges and serious color difference between the front and back sides of the cloth.

[0033] Table 1 Test results of Examples 1-6 and Comparative Examples 1-2

[0034]

[0035]

[0036] It can be seen from the comparison of the above-mentioned examples and comparative examples that in this application, by installing a double-row drying cylinder and a temperature and humidity detection system before steam heating, improving the drying cylinder, and installing a C-type steam adjustable heating device on the outer layer, the curling phenomenon of knitted fabrics can be solved, the liquid-carrying rate of the cloth surface can be reduced, steam consumption can be reduced, the pre-drying degree of both sides of the cloth can be controlled, the dye migration during the dyeing process of knitted fabrics can be reduced, the dye hydrolysis can be alleviated, and the dye uptake rate and color fixation rate can be improved. In the prior art, drying with a drying cylinder will result in non-conforming products with slight shrinkage and curling of the cloth surface but serious color difference between the front and back sides of the cloth, while using hot air drying will result in non-conforming products with serious shrinkage and curling of the edges and serious color difference between the front and back sides of the cloth.

[0037] For purposes of illustration, the foregoing description uses specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to those skilled in the art that the described embodiments can be practiced without specific details. Accordingly, the foregoing description of the specific embodiments described herein is presented for purposes of illustration and description. These descriptions are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to those of ordinary skill in the art that many modifications and variations are possible in light of the above teachings. Additionally, when used herein to refer to the position of components, the terms above and below, or their synonyms, do not necessarily refer to an absolute position relative to an external reference, but rather to a relative position with respect to the reference drawings of the components.

[0038] In addition, the foregoing drawings and description include many concepts and features that can be combined in various ways to achieve various beneficial effects and advantages. Accordingly, features, components, elements, and / or concepts from various different drawings can be combined to produce embodiments or implementations that may not be shown or described in this specification. Additionally, not all features, components, elements, and / or concepts shown in a particular drawing or description need to be present in any specific embodiment and / or implementation. It should be understood that such embodiments and / or implementations fall within the scope of this specification.

Claims

1. An improved dyeing process of reactive dyes for all-cotton knitted fabrics by short wet steaming, characterized in that, The steps include: S1. Padding with the dye liquor and auxiliaries. Among them, the dye liquor includes: 0 - 70 g / L of dye, 1.0 - 5.0 g / L of penetrant, 1.0 - 5.0 g / L of anti-migration agent; the formula of the auxiliaries includes: 20 - 40 g / L of soda ash, 20 - 60 g / L of sodium sulfate; the padding percentage is 70 - 80%; S2. Quick drying with drying cylinders. Add double rows of drying cylinders and a temperature and humidity detection system. Install a C-type steam adjustable heating device on the outer layer of the drying cylinders, with a temperature of 50 - 100 °C, so that the final liquor ratio of the dyed cloth is controlled within 30 ± 5%; S3. Quick steaming with saturated steam. Among them, the temperature of the steaming box is 102 °C, and the steaming time is 1 - 2 min; S4. Cold water washing, washing at room temperature, passing through 2 water washing tanks; S5. Hot water washing; S6. Soaping; S7. High-temperature water washing; S8. Acid washing.

2. The dyeing process according to claim 1, characterized in that, The drying cylinders are steam drying cylinders in the dyeing factory, and the surfaces are treated with Teflon to prevent color staining.

3. The dyeing process according to claim 1, characterized in that, S4. Cold water washing, washing at room temperature, passing through 2 water washing tanks; S5. Hot water washing, washing with 80 °C hot water, passing through 1 water washing tank; S6. Soaping, using soaping liquor, soaping at 98 °C, passing through 1 soaping tank; S7. High-temperature water washing, the water washing temperature is 80 °C, passing through 1 water washing tank; then rinsing with warm water, passing through 1 water washing tank; S8. Acid washing, using 1 g / L acetic acid solution, acid washing at room temperature, passing through 1 acid washing tank, then rinsing with normal-temperature clear water, passing through 1 water washing tank.

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