Water-free washing process for washing denim and equipment applying water-free washing process

Abstract

The invention discloses a water-free washing process for washing denim and equipment applying the water-free washing process, relates to the field of textile washing treatment, and aims to lighten the color of the denim and realize the washing effect by utilizing a supercritical fluid to excessively attached dye separated out of the denim after dyeing. Compared with water, the supercritical fluid has low viscosity, large density and good flowing, mass transfer and dissolving properties, the solubility of the dye in the supercritical fluid is higher, the dye can be better dissolved, and the use of chemical auxiliaries is reduced; a traditional denim washing process can be replaced, water is not used as a solvent, and no waste water is generated in the whole washing process; moreover, the dye and the supercritical medium after water washing can be separated, recycled and reused through the recycling and filtering device, so that the energy consumption is reduced, the production efficiency is improved, and water-free and green denim manufacturing is realized.

Description

Technical Field

[0001] The invention relates to the field of textile washing water treatment, in particular to a waterless washing process for washing denim fabric and equipment using the same. Background Art

[0002] The dyeing of denim fabrics is mainly based on indigo, which is a non-solid color that cannot be directly dissolved in water or directly dyed with cotton yarn. It can only be dyed by oxidation and then reduction. Therefore, in the process of dyeing, indigo cannot achieve a 100% dyeing rate, which will cause a large amount of floating color on the denim fabric. This part of the floating color is washed away by several clean water tanks before the sizing tank during the sizing process, but there are still many remaining on the yarn, so the finished fabric after weaving and finishing still contains a large amount of floating color. And this part of the floating color needs to be washed through the washing process to prevent the floating color remaining in the denim fabric from staining the wearer's skin or other clothes. In addition, existing consumers also pursue the old effect of denim fabrics, hoping that the denim fabrics can be washed and faded to different degrees, showing a natural worn-in effect, creating different denim styles.

[0003] However, the washing process is also one of the processes that consumes the most water resources. Washing is generally divided into various washing processes such as general washing, enzyme washing, stone washing, sand washing, rinsing, chemical washing, etc. In the production process of denim fabrics, a large amount of water and chemical reagents are generally used in the traditional denim washing process, resulting in large wastewater discharge and serious pollution. Summary of the invention

[0004] The purpose of the present invention is to provide a waterless washing process for washing denim fabrics and equipment using the same, so as to solve the problem that the above-mentioned washing process for denim fabrics consumes a large amount of water and causes serious pollution.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides a waterless washing process for washing water-washed denim fabric, comprising the following steps:

[0007] Step A: Wrap the denim fabric around a washing drum having a plurality of through holes on its side wall to obtain a washing drum with the denim fabric, wherein the plurality of through holes are spaced apart on the side wall of the washing drum, and a first conduit is plugged into one end of the washing drum;

[0008] Step B: installing the washing cylinder with the denim fabric in a supercritical reactor, wherein the supercritical reactor is connected to a second conduit; the first conduit passes through the supercritical reactor;

[0009] Step C: preheating the supercritical reactor and adjusting the gas pressure of the supercritical reactor;

[0010] Step D: introducing a supercritical medium into the first conduit so that the supercritical medium immerses the denim fabric and dissolves the dye on the denim fabric, and discharging the supercritical fluid from the second conduit;

[0011] Step E: decompressing the discharged supercritical medium to recover the dye dissolved from the denim fabric;

[0012] Step F: After the temperature in the supercritical reactor drops to room temperature and the air pressure drops to atmospheric pressure, the denim fabric is taken out from the washing cylinder to obtain washed denim fabric.

[0013] In the waterless washing process for washing denim fabric, between step C and step D, or between step D and step E, step G is further included, and step G includes the following steps: introducing a supercritical medium into the second conduit to immerse the denim fabric in the supercritical medium and dissolve the dye on the denim fabric, and discharging the supercritical fluid from the first conduit, the washing water temperature and washing water time in step G are the same as the washing water temperature and washing water time in step D, and the flow rate flowing into the supercritical reactor, the flow rate flowing out of the supercritical reactor and the gas pressure of the supercritical reactor in step G are the same as the flow rate flowing into the supercritical reactor, the flow rate flowing out of the supercritical reactor and the gas pressure of the supercritical reactor in step D.

[0014] In the waterless washing process for washing water-washed denim fabric, in the step D, the washing water temperature in the supercritical reactor is 32-40° C., and the gas pressure in the supercritical reactor is 8-100 MPa.

[0015] In the waterless washing process for washed denim fabric, the washing time in step D is 1 to 8 hours.

[0016] In the waterless washing process for washed denim fabric, the flow rate of the supercritical medium flowing into the supercritical reactor is 1-40 L / h, and the flow rate of the supercritical fluid flowing out of the supercritical reactor is the same as the flow rate of the supercritical medium flowing into the supercritical reactor.

[0017] The present invention also provides a denim cloth washing equipment, which uses the above-mentioned waterless washing process for washing denim cloth, including a gas storage device, a liquefaction device, a pressurizing device, a supercritical reactor, a pressure reducing device, a filtering and recovering device, a first connecting branch, a second connecting branch, a third connecting branch and a fourth connecting branch;

[0018] The axis of the supercritical reactor is arranged transversely along the X-axis direction, a reaction chamber is arranged in the supercritical reactor, and a water washing cylinder is arranged transversely in the reaction chamber along the X-axis direction; a containing cavity is arranged in the water washing cylinder, a plurality of through holes are arranged at intervals on the side wall of the water washing cylinder, and a first conduit is inserted into one end of the water washing cylinder;

[0019] The supercritical reactor is provided with a first connection port and a second connection port; one end of the first conduit is connected to the first connection port; the other end of the first conduit is connected to the accommodating chamber; the second connection port is provided with a second conduit;

[0020] The gas storage device, the liquefaction device and the boosting device are connected in sequence; the output end of the boosting device is connected to the second conduit through a first connecting branch, and the first connecting branch is provided with a first connecting valve; the first conduit is connected to the input end of the pressure reducing device through a second connecting branch, and the first connecting branch is provided with a second connecting valve;

[0021] One end of the third communication branch is connected to the output end of the supercharging device, the other end of the third communication branch is connected to the first conduit, and the third communication branch is provided with a third communication valve; one end of the fourth communication branch is connected to the second conduit, the other end of the fourth communication branch is connected to the input end of the decompression device, and the fourth communication branch is provided with a fourth communication valve;

[0022] The output end of the pressure reducing device is communicated with the filtering and recovering device.

[0023] The denim cloth washing equipment also includes an auxiliary agent feeding branch, one end of which is connected to the second conduit, and the other end of which is connected to an auxiliary agent feeding branch port, and the auxiliary agent feeding branch is provided with a fifth connecting valve and a one-way valve in sequence.

[0024] In the denim cloth washing equipment, the first connection port and the second connection port are respectively installed with pressure transmitters for monitoring and controlling the pressure in the supercritical reactor, and the pressure transmitter is communicatively connected with the pressurizing device and the decompressing device.

[0025] In the denim washing equipment, the supercritical reactor includes a supercritical reactor body, a heating device and a temperature detection sensor. The heating device is arranged on the periphery of the supercritical reactor body, and the detection end of the temperature detection sensor is arranged in the reaction chamber for detecting the temperature in the reaction chamber.

[0026] In the denim cloth washing equipment, the filtering and recovering device comprises a solid particle filtering device, a breathable membrane filtering device and a liquid filtering device which are connected in sequence.

[0027] A technical solution in the present invention can have the following beneficial effects:

[0028] The present invention utilizes supercritical fluid to precipitate excessive dyes attached to denim after dyeing, lighten the color of denim, and achieve the effect of washing. Compared with water, supercritical fluid has low viscosity, high density, good flow, mass transfer and solubility. Dyes have higher solubility in supercritical fluid, can better dissolve dyes, and reduce the use of chemical additives; it can replace the traditional denim washing process. Since water is not used as a solvent, the entire washing process does not generate wastewater; moreover, the dyes and supercritical medium after washing can be separated, recycled and reused through a recovery and filtration device, reducing energy consumption, improving production efficiency, and realizing waterless and green denim manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of one embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure of a supercritical reactor in one embodiment of the present invention;

[0031] Figure 3 is a schematic structural diagram of a filtering and recovering device in one embodiment of the present invention;

[0032] In the attached figure: gas storage device 1, liquefaction device 2, pressurizing device 3, supercritical reactor 4, pressure reducing device 5, filtering and recovering device 6;

[0033] A water washing cylinder 41, a supercritical reactor body 42, a heating device 43, a temperature detection sensor 44; a solid particle filtering device 61, a breathable membrane filtering device 62, a liquid filtering device 63, a first connecting branch 71, a second connecting branch 72, a third connecting branch 73, a fourth connecting branch 74; an auxiliary agent feeding branch 75;

[0034] The reaction chamber 401 and the second conduit 402 ; the accommodating chamber 410 ; the through hole 411 ; the first conduit 412 ; the first connecting valve 711 ; the second connecting valve 721 ; the third connecting valve 731 ; the fourth connecting valve 741 ; the fifth connecting valve 751 and the one-way valve 752 . DETAILED DESCRIPTION

[0035] The technical scheme of the present invention is further illustrated by specific embodiments below. In order to facilitate understanding of the present invention, the present invention is described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] The present invention provides a waterless washing process for washing water-washed denim fabric, comprising the following steps:

[0039] Step A: Wrap the denim fabric around a washing drum 41 with a plurality of through holes on its side wall to obtain the washing drum 41 with the denim fabric, wherein the side wall of the washing drum 41 is provided with a plurality of through holes 411 at intervals, and a first conduit 412 is plugged into one end of the washing drum 41;

[0040] Step B: installing the washing cylinder 41 with the denim fabric in the supercritical reactor 4, the supercritical reactor 4 is connected with the second conduit 402; the first conduit 412 passes through the supercritical reactor 4;

[0041] Step C: preheating the supercritical reactor 4 and adjusting the gas pressure of the supercritical reactor 4;

[0042] Step D: introducing a supercritical medium into the first conduit 412 to allow the supercritical medium to immerse the denim fabric and dissolve the dye on the denim fabric, and discharging the supercritical fluid from the second conduit 402;

[0043] Step E: decompressing the discharged supercritical medium to recover the dye dissolved from the denim fabric;

[0044] Step F: After the temperature in the supercritical reactor 4 drops to room temperature and the air pressure drops to atmospheric pressure, the denim fabric is taken out from the washing cylinder 41 to obtain washed denim fabric.

[0045] The washing cylinder 41 is provided with a first conduit 412, and the side wall of the washing cylinder 41 is provided with a plurality of through holes 411 at intervals. The supercritical fluid enters the interior of the washing cylinder 41 from the first conduit 412, passes through the denim fabric through the through holes 411, and enters the interior of the supercritical reactor 4; the supercritical fluid can dissolve the dye, so that the dye is removed from the denim fabric, causing the denim fabric to fade; then, the supercritical fluid is discharged from the supercritical reactor 4 from the second conduit 402. In a specific embodiment of the present invention, the washing cylinder 41 is specifically a washing drum.

[0046] When the supercritical reactor 4 reaches the preset temperature and pressure, the supercritical medium is continuously injected into the supercritical reactor 4, and the liquid supercritical medium will enter the supercritical state and become a supercritical fluid to dissolve the dye on the denim fabric. At the same time, the supercritical fluid that has dissolved the dye is discharged. Since new supercritical fluid is continuously added, the concentration of the dye in the supercritical fluid can be reduced to prevent the supercritical fluid from reaching a saturated state. In the above-mentioned washing process, while the supercritical medium is introduced into the first conduit 412, the supercritical fluid is discharged from the second conduit 402. The supercritical fluid continuously flows in and out, which can maximize the solubility of the indigo dye in the supercritical fluid, improve the washing effect, and achieve the purpose of washing denim.

[0047] When the supercritical fluid is decompressed, it exits the supercritical state and becomes a liquid and gas state. The indigo dye cannot be dissolved in the liquid and gas supercritical medium environment, so it is separated from the supercritical medium and discharged with the gaseous supercritical medium. The staff can recover the indigo dye.

[0048] The present invention utilizes supercritical fluid to precipitate excessive dyes attached to denim after dyeing, lighten the color of denim, and achieve the effect of washing. Compared with water, supercritical fluid has low viscosity, high density, good flow, mass transfer and solubility. Dyes have higher solubility in supercritical fluid, can better dissolve dyes, and reduce the use of chemical additives; it can replace the traditional denim washing process. Since water is not used as a solvent, the entire washing process does not generate wastewater; moreover, the dyes and supercritical medium after washing can be separated, recycled and reused through a recovery and filtration device, reducing energy consumption, improving production efficiency, and realizing waterless and green denim manufacturing.

[0049] Preferably, between step C and step D, or between step D and step E, step G is further included, and step G includes the following steps: introducing a supercritical medium into the second conduit 402 to immerse the denim fabric and dissolve the dye on the denim fabric, and discharging the supercritical fluid from the first conduit 412, the washing water temperature and washing time in step G are the same as the washing water temperature and washing time in step D, and the flow rate flowing into the supercritical reactor 4, the flow rate flowing out of the supercritical reactor 4 and the supercritical reactor pressure in step G are the same as the flow rate flowing into the supercritical reactor 4, the flow rate flowing out of the supercritical reactor 4 and the supercritical reactor pressure in step D.

[0050] Before step D, or after step D, a supercritical medium is introduced into the second conduit 402, and then the supercritical fluid is discharged from the first conduit 412, so that the supercritical fluid enters the interior of the supercritical reactor 4 from the second conduit 402, passes through the denim fabric, and then enters the interior of the washing cylinder 41 through the through hole 411, and then is discharged from the supercritical reactor 4 from the first conduit 412. In step D, the supercritical fluid enters the outer layer from the inner layer of the rolled denim fabric, and then is discharged from the supercritical reactor 4; while in the above step, the supercritical fluid enters the inner layer from the outer layer of the rolled denim fabric, and then is discharged from the interior of the washing cylinder 41.

[0051] Through the above steps, the denim fabric can be further washed to form a pressure difference between the inner layer and the outer layer to ensure uniform washing effect of the inner and outer layers, and prevent the problem of excessive layers of the denim fabric roll, which leads to better washing effect of the first layer of the denim fabric that contacts the first layer, resulting in color difference in washing effect between the inner layer and the outer layer of the denim fabric roll, and uneven washing, so that excess dye on the denim fabric can be further separated from the denim fabric.

[0052] In a specific embodiment of the present invention, supercritical carbon dioxide is used for washing water, and carbon dioxide gas in a supercritical state is injected into a supercritical reactor 4 in a purely physical manner, so that the dye on the denim in the supercritical reactor 4 is dissolved; then, the carbon dioxide gas in a supercritical state is discharged from the supercritical reactor 4, and the pressure is reduced, and the carbon dioxide is converted from a supercritical state to a liquid and gaseous state. Since indigo dye cannot be dissolved in a liquid and gaseous carbon dioxide environment, the dye is separated from the carbon dioxide and discharged along with the carbon dioxide gas, and the staff can recover the carbon dioxide gas-liquid mixture mixed with the dye.

[0053] Specifically, in the step D, the temperature of the washing water in the supercritical reactor 4 is 32-40° C., and the gas pressure in the supercritical reactor 4 is 8-100 MPa.

[0054] The purpose of the waterless washing process is to precipitate the excessive pigments attached to the denim after dyeing, so as to lighten the color of the denim and form a washing effect. During the washing process, it is necessary to maximize the solubility of the indigo dye in the supercritical medium. When the temperature is closer to the supercritical critical temperature, the density of supercritical carbon dioxide is greater and the solubility is improved. Therefore, the washing water temperature needs to be controlled at 32-40°C and the air pressure at 8-100MP during the washing process.

[0055] Specifically, in step D, the washing time is 1 to 8 hours.

[0056] The length of washing time can be selected according to the desired degree of distressing of the denim. The longer the washing time, the more the denim will fade. When the denim needs a darker color, choose a shorter washing time. When the denim needs a lighter color, choose a longer washing time. The washing time determines the degree of fading of the denim and affects the style of the denim.

[0057] Specifically, the flow rate of the supercritical medium flowing into the supercritical reactor 4 is 1-40 L / h, and the flow rate of the supercritical fluid flowing out of the supercritical reactor 4 is the same as the flow rate of the supercritical medium flowing into the supercritical reactor 4 .

[0058] Indigo dye is dissolved by supercritical fluid in the supercritical environment of the kettle and enters into carbon dioxide, keeping the flow rate of liquid flowing into the washing water system and the flow rate out the same, controlling the carbon dioxide in the kettle to be in a supercritical fluid state, and achieving the washing effect by continuously adding and discharging the indigo dye.

[0059] When the flow rate of the supercritical fluid is lower than 1 L / h, the solubility of the dye in the supercritical fluid is high, which slows down the dissolution rate of the dye and reduces the washing effect. When the flow rate of the supercritical fluid is lower than 40 L / h, the flow rate of the supercritical fluid is too fast, and the supercritical fluid fails to fully dissolve more dyes, that is, it is discharged from the supercritical reactor 4, which reduces the utilization rate of the supercritical fluid, resulting in the inability to effectively use the supercritical fluid for washing, resulting in a waste of energy consumption.

[0060] The flow rate of the supercritical fluid flowing out of the supercritical reactor 4 is the same as the flow rate of the supercritical medium flowing into the supercritical reactor 4, which can reduce the influence of the pressure change on the supercritical state, thereby avoiding reducing the ability of the supercritical fluid to dissolve the dye.

[0061] Please refer to Figures 1 to 3 The present invention provides a denim cloth washing equipment, which uses the above-mentioned waterless washing process for washing denim cloth, including a gas storage device 1, a liquefaction device 2, a pressurizing device 3, a supercritical reactor 4, a decompression device 5, a filtering and recovering device 6, a first connecting branch 71, a second connecting branch 72, a third connecting branch 73 and a fourth connecting branch 74;

[0062] The axis of the supercritical reactor 4 is arranged transversely along the X-axis direction, and a reaction chamber 401 is arranged in the supercritical reactor 4, and a water washing cylinder 41 is arranged transversely in the reaction chamber 401 along the X-axis direction; a receiving chamber 410 is arranged in the water washing cylinder 41, and a plurality of through holes 411 are distributed at intervals on the side wall of the water washing cylinder 41, and a first conduit 412 is inserted into one end of the water washing cylinder 41;

[0063] The supercritical reactor 4 is provided with a first connection port and a second connection port; one end of the first conduit 412 is connected to the first connection port; the other end of the first conduit 412 is connected to the accommodating chamber 410; the second connection port is provided with a second conduit 402;

[0064] The gas storage device 1, the liquefaction device 2 and the boosting device 3 are connected in sequence; the output end of the boosting device 3 is connected to the second conduit 402 through a first connecting branch 71, and the first connecting branch 71 is provided with a first connecting valve 711; the first conduit 412 is connected to the input end of the pressure reducing device 5 through a second connecting branch 72, and the first connecting branch 71 is provided with a second connecting valve 721;

[0065] One end of the third communication branch 73 is communicated with the output end of the supercharging device 3, and the other end of the third communication branch 73 is communicated with the first conduit 412, and the third communication branch 73 is provided with a third communication valve 731; one end of the fourth communication branch 74 is communicated with the second conduit 402, and the other end of the fourth communication branch 74 is communicated with the input end of the decompression device 5, and the fourth communication branch 74 is provided with a fourth communication valve 741;

[0066] The output end of the pressure reducing device 5 is communicated with the filtering recovery device 6 .

[0067] In a specific embodiment of the present invention, the gas storage device 1 is specifically a carbon dioxide gas cylinder; the boosting device 3 is a boosting pump, and the decompression device 5 is a decompression pump.

[0068] The gas storage device 1 is used to provide a gaseous supercritical medium, and the liquefaction device 2 is used to convert the gaseous supercritical medium into a liquid supercritical medium; the liquid supercritical medium is input into the supercritical reactor 4 through the booster device, and the temperature and gas pressure in the supercritical reactor 4 are adjusted to make the liquid supercritical medium enter a supercritical state to form a supercritical fluid.

[0069] When performing step D, the first connecting valve 711 and the second connecting valve 721 are opened, and the third connecting valve 731 and the fourth connecting valve 741 are closed, and the supercritical medium enters the supercritical reactor 4 through the first connecting branch 71 and the second conduit 402 in sequence, and the supercritical fluid enters the decompression device 5 through the first conduit 412 and the second connecting branch 72 in sequence.

[0070] When performing step G, the third connecting valve 731 and the fourth connecting valve 741 are opened, and the first connecting valve 711 and the second connecting valve 721 are closed, and the supercritical medium enters the supercritical reactor 4 through the third connecting branch 73 and the first conduit 412 in sequence, and the supercritical fluid enters the decompression device 5 through the second conduit 402 and the fourth connecting branch 74 in sequence.

[0071] Through the cooperation of the first connecting branch 71, the second connecting branch 72, the third connecting branch 73 and the fourth connecting branch 74, the operation of introducing the supercritical medium into the second conduit 402 and then discharging the supercritical fluid from the first conduit 412, and the operation of introducing the supercritical medium into the first conduit 412 and then discharging the supercritical fluid from the second conduit 402 are realized.

[0072] The axis of the supercritical reactor 4 is arranged horizontally along the X-axis direction, and the washing cylinder 41 is arranged horizontally in the reaction chamber 401 along the X-axis direction, that is, the supercritical reactor 4 is arranged horizontally. After the denim is dyed and finished, the washing process is a denim with a certain width. The denim is usually wound together through a paper tube or a warp shaft. Usually, a roll of cloth weighs hundreds of kilograms or even several tons. By designing the horizontal supercritical reactor 4 and the washing cylinder 41, it is convenient for the denim to enter and exit the equipment in reality.

[0073] The denim cloth washing equipment is provided with a gas storage device 1, a liquefaction device 2, a pressure-boosting device 3, a supercritical reactor 4, a pressure-reducing device 5 and a filtering and recovering device 6. The supercritical fluid is used to precipitate the excessively attached dyes on the denim cloth after dyeing, and the color of the denim cloth is lightened to achieve the effect of washing. The equipment can replace the traditional denim washing process. Since water is not used as a solvent, the whole washing process does not generate wastewater, and the use of chemical additives is reduced. Moreover, the dyes and supercritical media after washing can be separated, recovered and reused through a recovery and filtering device, thereby reducing energy consumption, improving production efficiency and realizing waterless and green denim manufacturing.

[0074] Optionally, it further includes an auxiliary agent feeding branch 75, one end of which is connected to the second conduit 402, and the other end of which is connected to an auxiliary agent feeding branch port, and the auxiliary agent feeding branch 75 is provided with a fifth connecting valve 751 and a one-way valve 752 in sequence.

[0075] The auxiliary agent feeding branch 75 is used to feed auxiliary agents. By feeding auxiliary agents, the solubility of the dye is increased, the color of the denim is lightened, and the washing effect is achieved. When auxiliary agents need to be fed, the fifth connecting valve 751 is opened, and auxiliary agents are fed into the auxiliary agent feeding branch port. The one-way valve 752 can prevent the supercritical medium from flowing out of the auxiliary agent feeding branch 75 in reverse.

[0076] Preferably, the first connection port and the second connection port are respectively installed with pressure transmitters for monitoring and controlling the pressure in the supercritical reactor 4 , and the pressure transmitters are communicatively connected with the pressurizing device 3 and the decompressing device 5 .

[0077] When the gas pressure in the supercritical reactor 4 is higher than the set value, the supercritical fluid in the supercritical reactor 4 is discharged through the pressure reducing device 5, and the pressure release is quantitatively controlled. At the same time, the input of the supercritical fluid is reduced through the pressure increasing device 3. When the gas pressure in the supercritical reactor 4 is lower than the set value, the input of the supercritical fluid is increased through the pressure increasing device 3, and the output of the supercritical fluid is reduced through the pressure reducing device 5.

[0078] In a preferred embodiment of the present invention, the pressure transmitter can display the pressure and flow rate changes in the supercritical reactor 4 in real time through the Bluetooth module, and at the same time feed back to the boosting device 3 and the pressure reducing device 5 for real-time monitoring and adjustment. The pressure transmitter monitors the boosting device 3 and the pressure reducing device 5 to control the flow rate, so as to achieve the dynamic balance of supercritical carbon dioxide in the supercritical reactor 4.

[0079] Specifically, the supercritical reactor 4 includes a supercritical reactor body 42, a heating device 43 and a temperature detection sensor 44, wherein the heating device 43 is arranged on the periphery of the supercritical reactor body 42, and the detection end of the temperature detection sensor 44 is arranged in the reaction chamber 401 for detecting the temperature in the reaction chamber 401.

[0080] The heating device 43 is specifically one of an oil bath heating device, an electric heating wire device or a ceramic heating plate, and the temperature of the reaction chamber 401 is kept constant by the heating device 43. The temperature detection sensor 44 is used to detect the reaction chamber 401. The staff adjusts the heating temperature of the heating device 43 in time according to the temperature of the reaction chamber 401, so that the temperature of the reaction chamber 401 is maintained at an ideal value.

[0081] Specifically, the filtering and recovering device 6 comprises a solid particle filtering device 61 , a breathable membrane filtering device 62 and a liquid filtering device 63 which are connected in sequence.

[0082] The filtration and recovery system filters and separates the supercritical medium carrying the dye, and performs separation and filtration through the solid particle filter device 61, the breathable membrane filter device 62 and the liquid filter device 63. After the supercritical fluid is depressurized, it exits the supercritical state, causing the dye to precipitate. Through the cooperation of the solid particle filter device 61, the breathable membrane filter device 62 and the liquid filter device 63, the dye can be effectively separated and recovered.

[0083] Example 1

[0084] A waterless washing process for washing denim fabrics comprises the following steps:

[0085] Step A: Wrap the denim fabric around the washing cylinder 41 to obtain the washing cylinder 41 with the denim fabric, wherein the side wall of the washing cylinder 41 is provided with a plurality of through holes 411 at intervals, and a first conduit 412 is plugged into one end of the washing cylinder 41;

[0086] Step B: installing the washing cylinder 41 with the denim fabric in the supercritical reactor 4, the supercritical reactor 4 is connected with the second conduit 402; the first conduit 412 passes through the supercritical reactor 4;

[0087] Step C: preheating the supercritical reactor 4 and adjusting the gas pressure of the supercritical reactor 4; the washing water temperature in the supercritical reactor 4 is 32° C., and the gas pressure in the supercritical reactor 4 is 8 MPa.

[0088] Step D: introducing a supercritical medium into the first conduit 412, so that the supercritical medium immerses the denim fabric and dissolves the dye on the denim fabric, and the supercritical fluid is discharged from the second conduit 402; the washing time is 1 hour; the flow rate of the supercritical medium flowing into the supercritical reactor 4 is 1L / h; the flow rate of the supercritical fluid flowing into the supercritical reactor 4 is 1L / h;

[0089] Step E: decompressing the discharged supercritical medium to recover the dye dissolved from the denim fabric;

[0090] Step F: After the temperature in the supercritical reactor 4 drops to room temperature and the air pressure drops to atmospheric pressure, the denim fabric is taken out from the washing cylinder 41 to obtain washed denim fabric.

[0091] Example 2

[0092] The steps of Example 2 are basically the same as those of Example 1, except that, between Step D and Step E, Step G is further included, and Step G includes the following steps: introducing a supercritical medium into the second conduit 402 to immerse the denim fabric and dissolve the dye on the denim fabric, and discharging the supercritical fluid from the first conduit 412, and the washing water temperature, washing water time, flow rate flowing into the supercritical reactor 4, flow rate flowing out of the supercritical reactor 4 and supercritical reactor pressure in Step G are the same as the washing water temperature, washing water time, flow rate flowing into the supercritical reactor 4, flow rate flowing out of the supercritical reactor 4 and supercritical reactor pressure in Step D.

[0093] Example 3

[0094] The steps of Example 3 are the same as those of Example 2, except that the washing water temperature in the supercritical reactor 4 is 40° C., the gas pressure in the supercritical reactor 4 is 100 MPa, the washing time is 8 hours, the flow rate of the supercritical medium flowing into the supercritical reactor 4 is 40 L / h, and the flow rate of the supercritical fluid flowing into the supercritical reactor 4 is 40 L / h.

[0095] Example 4

[0096] The steps of Example 4 are the same as those of Example 2, except that the washing water temperature in the supercritical reactor 4 is 35° C., the gas pressure in the supercritical reactor 4 is 15 MPa, the washing time is 5 h, the flow rate of the supercritical medium flowing into the supercritical reactor 4 is 25 L / h, and the flow rate of the supercritical fluid flowing into the supercritical reactor 4 is 25 L / h.

[0097] Comparative Example 1

[0098] The indigo dye is attached to the denim fiber using the existing technology, and the steps include:

[0099] The denim fabric is washed in clean water at 40°C with a bath ratio of 1:10, and then soap powder is added to soap wash for 10 minutes at 60°C, and then washed in clean water at 40°C; then softener is added to soften the fabric at 40°C for 10 minutes, and then dehydrated and dried to obtain washed denim fabric.

[0100] The denim fabrics of Examples 1 to 4 and Comparative Example 1 were first tested for K / S values. After the washing process, the washed denim fabrics obtained from Examples 1 to 4 and Comparative Example 1 were tested for K / S values ​​again, and the color fastness to soaping and the color fastness to rubbing were tested. The results are shown in Table 1.

[0101] Test method:

[0102] K / S value: Press the washed denim yarn or fabric on the light hole to make it opaque, and use SF600X colorimeter to measure the K / S value of the washed yarn or fabric at the maximum absorption wavelength. Take 3 different positions of each sample for testing and take the average value.

[0103] The color fastness to washing with soap was tested according to GB / T 3921-2008 “Textiles - Tests for Color Fastness - Color Fastness to Washing with Soap”; the color fastness to rubbing was tested according to GB / T 3920-2008 “Textiles - Tests for Color Fastness - Color Fastness to Rubbing”.

[0104] Table 1 - Test results

[0105] sample K / S value before washing K / S value after washing Color fastness to soap washing Color fastness to rubbing Example 1 25.2 17.6 4 4-5 Example 2 25.5 19.8 4 4-5 Example 3 25.9 18.2 3-4 4 Example 4 25.4 18.6 3 4 Comparative Example 1 25.7 21.4 3 3

[0106] By comparing Examples 1 to 4 with Comparative Example 1, the washing process of the present invention can replace the traditional denim washing process, does not use water and does not generate wastewater, reduces the use of chemical additives, and has basically no difference in appearance from denim fabric washed with ordinary water.

[0107] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific embodiments of the present invention without creative work, and these equivalent variations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A waterless washing process for washed denim fabrics, characterized in that: The following steps are involved: Step A: Wrap the denim fabric around a washing drum having a plurality of through holes on its side wall to obtain a washing drum with the denim fabric, wherein the plurality of through holes are spaced apart on the side wall of the washing drum, and a first conduit is plugged into one end of the washing drum; Step B: installing the washing cylinder with the denim fabric in a supercritical reactor, wherein the supercritical reactor is connected to a second conduit; the first conduit passes through the supercritical reactor; Step C: preheating the supercritical reactor and adjusting the gas pressure of the supercritical reactor; Step D: introducing a supercritical medium into the first conduit so that the supercritical medium immerses the denim fabric and dissolves the dye on the denim fabric, and discharging the supercritical fluid from the second conduit; Step E: decompressing the discharged supercritical medium to recover the dye dissolved from the denim fabric; Step F: After the temperature in the supercritical reactor drops to room temperature and the air pressure drops to atmospheric pressure, the denim fabric is taken out from the washing cylinder to obtain washed denim fabric.

2. The waterless washing process for washed denim fabric according to claim 1, characterized in that: Between step C and step D, or between step D and step E, step G is further included, and step G includes the following steps: introducing a supercritical medium into the second conduit to immerse the denim fabric in the supercritical medium and dissolve the dye on the denim fabric, and discharging the supercritical fluid from the first conduit; the washing water temperature and washing water time in step G are the same as the washing water temperature and washing water time in step D, and the flow rate flowing into the supercritical reactor, the flow rate flowing out of the supercritical reactor and the gas pressure of the supercritical reactor in step G are the same as the flow rate flowing into the supercritical reactor, the flow rate flowing out of the supercritical reactor and the gas pressure of the supercritical reactor in step D.

3. The waterless washing process for washed denim fabric according to claim 1, characterized in that: In the step D, the temperature of the washing water in the supercritical reactor is 32-40° C., and the gas pressure in the supercritical reactor is 8-100 MPa.

4. The waterless washing process for washed denim fabric according to claim 1, characterized in that: In step D, the washing time is 1 to 8 hours.

5. The waterless washing process for washed denim fabric according to claim 1, characterized in that: The flow rate of the supercritical medium flowing into the supercritical reactor is 1-40 L / h, and the flow rate of the supercritical fluid flowing out of the supercritical reactor is the same as the flow rate of the supercritical medium flowing into the supercritical reactor.

6. A denim washing device, characterized in that: The waterless washing process for washing water-washed denim fabrics according to any one of claims 1 to 5 comprises a gas storage device, a liquefaction device, a pressurizing device, a supercritical reactor, a pressure reducing device, a filtering and recovering device, a first connecting branch, a second connecting branch, a third connecting branch and a fourth connecting branch; The axis of the supercritical reactor is arranged transversely along the X-axis direction, a reaction chamber is arranged in the supercritical reactor, and a water washing cylinder is arranged transversely in the reaction chamber along the X-axis direction; a containing cavity is arranged in the water washing cylinder, a plurality of through holes are arranged at intervals on the side wall of the water washing cylinder, and a first conduit is inserted into one end of the water washing cylinder; The supercritical reactor is provided with a first connection port and a second connection port; one end of the first conduit is connected to the first connection port; the other end of the first conduit is connected to the accommodating chamber; the second connection port is provided with a second conduit; The gas storage device, the liquefaction device and the boosting device are connected in sequence; the output end of the boosting device is connected to the second conduit through a first connecting branch, and the first connecting branch is provided with a first connecting valve; the first conduit is connected to the input end of the pressure reducing device through a second connecting branch, and the first connecting branch is provided with a second connecting valve; One end of the third communication branch is connected to the output end of the supercharging device, the other end of the third communication branch is connected to the first conduit, and the third communication branch is provided with a third communication valve; one end of the fourth communication branch is connected to the second conduit, the other end of the fourth communication branch is connected to the input end of the decompression device, and the fourth communication branch is provided with a fourth communication valve; The output end of the pressure reducing device is communicated with the filtering and recovering device.

7. The denim washing equipment according to claim 6, characterized in that: It also includes an auxiliary agent feeding branch, one end of which is connected to the second conduit, and the other end of which is connected to an auxiliary agent feeding branch port. The auxiliary agent feeding branch is provided with a fifth connecting valve and a one-way valve in sequence.

8. The denim washing equipment according to claim 6, characterized in that: The first connection port and the second connection port are respectively equipped with pressure transmitters for monitoring and controlling the pressure in the supercritical reactor. The pressure transmitters are communicatively connected with the pressurizing device and the decompressing device.

9. The denim washing equipment according to claim 6, characterized in that: The supercritical reactor comprises a supercritical reactor body, a heating device and a temperature detection sensor. The heating device is arranged on the periphery of the supercritical reactor body. The detection end of the temperature detection sensor is arranged in the reaction chamber for detecting the temperature in the reaction chamber.

10. The denim washing equipment according to claim 6, characterized in that: The filtering and recovering device comprises a solid particle filtering device, a breathable membrane filtering device and a liquid filtering device which are connected in sequence.

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