Method for dyeing by using supercritical fluid

Abstract

The invention provides a method for dyeing by using supercritical fluid, and belongs to the technical field of dyeing processes. After the to-be-dyed object is wetted with water, the supercritical carbon dioxide fluid is utilized for pretreatment, the dye adsorption uniformity of the to-be-dyed object is improved, and therefore the dyeing quality is improved, and follow-up dyeing can be conducted under the mild condition; compared with the prior art, the non-toxic dyeing assistant and the recycled supercritical carbon dioxide fluid are adopted, so that the dyeing efficiency and quality are improved, the energy consumption is reduced, and the soaping-resistant color fastness and rubbing-resistant color fastness of the dyed fiber fabric are improved under lower pressure and temperature; due to the fact that the dyeing condition is mild, and the dyed supercritical carbon dioxide fluid contains few impurities, after the dye and the dyeing assistant are supplemented, the new to-be-dyed object is pretreated cooperatively, secondary dyeing can be directly carried out, that is, the supercritical carbon dioxide fluid can be dyed twice, the utilization rate of the supercritical carbon dioxide fluid is increased, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of dyeing processes, and particularly to a method for dyeing using supercritical fluids. Background Art

[0002] Traditional dyeing processes all use water as a carrier. Approximately 80 - 100 L of water is consumed for every 1 Kg of fabric dyed. With the global water resource crisis and the strengthening of environmental protection awareness, how to dye with less or no water has become an important research direction in the dyeing and finishing industry. Therefore, waterless dyeing technology deserves the attention of the entire dyeing and finishing industry. Waterless dyeing, scientifically known as supercritical fluid waterless dyeing technology. In the supercritical state, the supercritical fluid is in a semi-liquid and semi-gaseous state, which enables the supercritical fluid to have both the dissolving ability of a liquid and the diffusion ability of a gas. In the supercritical fluid waterless dyeing process, the supercritical fluid can both dissolve dyes and easily penetrate into the interior of textiles to complete the process of dye dissolution → adsorption → dyeing.

[0003] Currently, the supercritical carbon dioxide dyeing technology is a research hotspot. This technology uses supercritical CO2 as a dyeing medium to dissolve and deliver dyes into the fiber pores, enabling the dyes to be quickly and evenly dyed onto the fabric. After dyeing, CO2 can be fully separated from the dyes, and no washing, drying, and other operation processes are required. The unused dyes can be recycled. However, due to the system state of supercritical carbon dioxide fluid dyeing being at relatively high temperatures and pressures, there is a problem of high energy consumption. At the same time, since the entire system equipment is in a high-pressure sealed state, it is quite difficult to monitor the dyeing quality during the dyeing process. Therefore, developing a supercritical fluid dyeing process that can not only maintain the advantages of rapid dyeing under anhydrous conditions of supercritical fluids but also has relatively mild conditions and easy control of dyeing quality is an urgent expectation of the current printing and dyeing industry. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for dyeing using supercritical fluids. The method provided by the present invention, by using a non-toxic dye assistant and cooperating with supercritical carbon dioxide fluid, realizes improving the dyeing efficiency and quality at relatively lower pressures and temperatures compared to the prior art.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a method for dyeing using supercritical fluids, including the following steps: After wetting the object to be dyed with water, pre-treat it with supercritical carbon dioxide fluid to obtain the pre-treated object to be dyed and the recycled supercritical carbon dioxide fluid; Mix the dye, dye assistant, and the recycled supercritical carbon dioxide fluid, and perform the first dyeing on the pre-treated object to be dyed to obtain the fiber fabric after the first dyeing;

[0007] The dye assistant is composed of decamethylcyclopentasiloxane and a co-solvent.

[0008] Preferably, it includes the following steps:

[0009] After wetting the object to be dyed with water, wind it around a dyeing shaft and put it into a dyeing kettle; inject supercritical carbon dioxide fluid into the storage kettle, use the first circulation pump to make the supercritical carbon dioxide fluid inject into the dyeing kettle, and make the supercritical carbon dioxide fluid circulate between the inner and outer layers of the object to be dyed for pretreatment to obtain a pretreated object to be dyed, and the supercritical carbon dioxide fluid in the dyeing kettle is recycled to the storage kettle through the first circulation pump to obtain recycled supercritical carbon dioxide fluid;

[0010] Inject the mixture of the dye and the dye assistant into the dye kettle, and the dye assistant is composed of decamethylcyclopentasiloxane and a co-solvent;

[0011] Inject the recycled supercritical carbon dioxide fluid in the storage kettle into the dye kettle by using the second circulation pump, and make the supercritical carbon dioxide fluid dissolved with the dye and the dye assistant circulate between the inner and outer layers of the object to be dyed for the first dyeing to obtain a fiber fabric after the first dyeing;

[0012] And the supercritical carbon dioxide fluid after dyeing in the dye kettle is recycled to the dye kettle through the second circulation pump, and after adding the dye and the dye assistant, directly conduct the second dyeing to obtain a fiber fabric after the second dyeing.

[0013] Preferably, the time of the pretreatment is 20 - 40 min, the temperature of the pretreatment is 40 - 60 °C, and the pressure of the pretreatment is 8 - 10 MPa.

[0014] Preferably, the dye is a disperse dye, and the disperse dye includes at least one of disperse red 60, disperse yellow 54, disperse orange 25, disperse blue 56, disperse violet 1, disperse red 356, and disperse blue 366.

[0015] Preferably, the co-solvent includes at least one of absolute ethanol, n-propanol, and butanol.

[0016] Preferably, the volume ratio of decamethylcyclopentasiloxane to the co-solvent in the dye assistant is (3 - 18):2.

[0017] Preferably, the mass ratio of the dye to the dye assistant is (2 - 5):1.

[0018] Preferably, the mass ratio of the dye to the object to be dyed is (0.1 - 10):(400 - 800).

[0019] Preferably, during the first dyeing process, the temperature of the dyeing system is 60 - 90°C, the pressure of the dyeing system is 10 - 18 MPa, and the dyeing time is 60 - 110 min.

[0020] Preferably, after the second dyeing is completed, the following steps are further included: after reducing the pressure and temperature of the dyeing system, separating and recovering the dye, the dye assistant, and carbon dioxide, and taking out the fiber fabric after the second dyeing.

[0021] The present invention provides a method for dyeing using a supercritical fluid, which includes the following steps: after wetting the object to be dyed with water, performing pretreatment using supercritical carbon dioxide fluid to obtain the pretreated object to be dyed and the recovered supercritical carbon dioxide fluid; mixing the dye, the dye assistant, and the recovered supercritical carbon dioxide fluid, and dyeing the pretreated object to be dyed to obtain the dyed fiber fabric; the dye assistant is composed of decamethylcyclopentasiloxane and a co - solvent. After wetting the object to be dyed with water, the present invention performs pretreatment using supercritical carbon dioxide fluid, which improves the adsorption uniformity of the object to be dyed to the dye, thereby improving the dyeing quality and facilitating the subsequent dyeing under mild conditions; by using a non - toxic dye assistant and coordinating with the recovered supercritical carbon dioxide fluid, the dyeing efficiency and quality are improved under relatively lower pressure and temperature compared with the prior art, the energy consumption is reduced, and the soaping fastness and rubbing fastness of the dyed fiber fabric are improved; after dyeing in the dye kettle, the supercritical carbon dioxide fluid is recycled back to the dye kettle through the second circulation pump. Since the dyeing conditions are mild, there are fewer impurities in the supercritical carbon dioxide fluid after dyeing. After adding the dye and the dye assistant, it can directly perform the second dyeing by coordinating with the new object to be dyed, that is, the supercritical carbon dioxide fluid can be used for two dyeings, improving its utilization rate and reducing the energy consumption. Description of the Drawings

[0022] Figure 1 is the flow chart of the method for dyeing using a supercritical fluid in the present invention;

[0023] Figure 2 is the column statistical chart of the K / S values of the fiber fabrics after the first dyeing and the fiber fabrics after the second dyeing obtained in Examples 1 - 5 and Comparative Examples 1 - 3 of the present invention. Detailed Embodiments

[0024] The present invention provides a method for dyeing using a supercritical fluid, which includes the following steps: after wetting the object to be dyed with water, performing pretreatment using supercritical carbon dioxide fluid to obtain the pretreated object to be dyed and the recovered supercritical carbon dioxide fluid; mixing the dye, the dye assistant, and the recovered supercritical carbon dioxide fluid, and performing the first dyeing on the pretreated object to be dyed to obtain the dyed fiber fabric;

[0025] The dyeing auxiliary agent consists of decamethylcyclopentasiloxane and a cosolvent.

[0026] In the present invention, unless otherwise specified, the raw materials used are conventional commercial products in the art, and the dye kettle, dyeing kettle, circulating pump and other devices used are all commonly used equipment in the art.

[0027] In the present invention, the method for dyeing using a supercritical fluid preferably comprises the following steps:

[0028] Wetting the object to be dyed with water, winding it on a dyeing shaft and putting it into a dyeing kettle; injecting supercritical carbon dioxide fluid into the storage kettle, injecting the supercritical carbon dioxide fluid into the dyeing kettle by using a first circulation pump, and circulating the supercritical carbon dioxide fluid between the inner and outer layers of the object to be dyed to perform pretreatment, thereby obtaining a pretreated object to be dyed, and recycling the supercritical carbon dioxide fluid in the dyeing kettle into the storage kettle through the first circulation pump to obtain recycled supercritical carbon dioxide fluid;

[0029] The dye and the dyeing auxiliary are mixed and injected into a dye kettle, wherein the dyeing auxiliary consists of decamethylcyclopentasiloxane and a cosolvent;

[0030] The supercritical carbon dioxide fluid recovered from the storage kettle is injected into the dye kettle through a second circulation pump, and the supercritical carbon dioxide fluid dissolved with the dye and the dyeing auxiliary agent is circulated between the inner and outer layers of the object to be dyed to perform the first dyeing to obtain a dyed fiber fabric;

[0031] The supercritical carbon dioxide fluid after dyeing in the dye kettle is recovered into the dye kettle through a second circulation pump, and the second dyeing is directly performed after adding dye and dyeing auxiliary agent to obtain the fiber fabric after the second dyeing.

[0032] In the present invention, the pretreatment time is preferably 20 to 40 minutes, more preferably 25 to 36 minutes; the pretreatment temperature is preferably 40 to 60°C, more preferably 45 to 58°C; the pretreatment pressure is preferably 8 to 10 MPa, more preferably 8.4 to 9.7 MPa. The present invention wets the dyed object with water and then pretreats it with supercritical carbon dioxide fluid under the above conditions, thereby improving the uniformity of dye adsorption of the pretreated dyed object, improving the dyeing quality, and facilitating subsequent dyeing under mild conditions.

[0033] In the present invention, the dye is preferably a disperse dye; the disperse dye preferably includes at least one of disperse red 60, disperse yellow 54, disperse orange 25, disperse blue 56, disperse violet 1, disperse red 356, and disperse blue 366. The present invention selects the above-mentioned disperse dyes as dyes to improve the solubility, thermal stability and dyeing performance of the dye in supercritical carbon dioxide fluid, thereby improving the efficiency and quality of dyeing.

[0034] In the present invention, the co-solvent preferably includes at least one of absolute ethanol, n-propanol, and butanol. The co-solvent in the present invention is non-toxic, and can significantly improve the solubility of the dye in cooperation with decamethylcyclopentasiloxane, thereby improving the efficiency and quality of dyeing.

[0035] In the present invention, the volume ratio of decamethylcyclopentasiloxane to the co-solvent in the dye assistant is preferably (3 - 18):2, more preferably (5 - 15):2. By controlling the volume ratio of decamethylcyclopentasiloxane to the co-solvent within the above range in the present invention, the solubility of the dye is significantly improved, thereby improving the dyeing efficiency and quality, and enabling supercritical fluid dyeing to be carried out at relatively lower pressures and temperatures compared to the prior art.

[0036] In the present invention, the mass ratio of the dye to the dye assistant is preferably (2 - 5):1, more preferably (2.5 - 4):1. By controlling the mass ratio of the dye to the dye assistant within the above range in the present invention, the solubility of the dye is improved, thereby improving the dyeing efficiency and quality, and enabling supercritical fluid dyeing to be carried out at relatively lower pressures and temperatures compared to the prior art.

[0037] In the present invention, the mass ratio of the dye to the object to be dyed is preferably (0.1 - 10):(400 - 800). By controlling the mass ratio of the dye to the object to be dyed within the above range in the present invention, resources are saved while ensuring the dyeing efficiency and quality.

[0038] In the present invention, during the dyeing process, the temperature of the dyeing system is preferably 60 - 90°C, more preferably 65 - 89°C; the pressure of the dyeing system is preferably 10 - 18 MPa, more preferably 12 - 16 MPa; the dyeing time is preferably 60 - 110 min, more preferably 80 - 100 min. By controlling the temperature and pressure of the dyeing system, as well as the dyeing time within the above ranges in the present invention, energy consumption is reduced, and the dyeing efficiency and quality are improved at relatively lower pressures and temperatures compared to the prior art.

[0039] In the present invention, the amounts of the additional dye and dye assistant are preferably based on the contents of the dye and dye assistant in the supercritical carbon dioxide fluid after dyeing. In the present invention, the mass of the additional dye preferably accounts for 15% - 50% of the mass of the dye used in the first dyeing process; the mass of the additional dye assistant preferably accounts for 5% - 30% of the mass of the dye assistant used in the first dyeing process.

[0040] In the present invention, before the second dyeing, the new object to be dyed is preferably first wetted and pretreated.

[0041] In the present invention, after the second dyeing is completed, it further includes: after reducing the pressure and temperature of the dyeing system, separating and recovering the dye, dye assistant, and carbon dioxide, and taking out the fiber fabric after the second dyeing.

[0042] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] Except as otherwise specified, all experiments were repeated 3 times, and the results were expressed as the average value.

[0044] Example 1

[0045] A method for dyeing using supercritical fluid is as follows:

[0046] The polyester fiber to be dyed is wetted with water, wound on a dyeing shaft and placed in a dyeing kettle; supercritical carbon dioxide fluid is injected into the storage kettle, and the supercritical carbon dioxide fluid is injected into the dyeing kettle by using the first circulation pump, and the supercritical carbon dioxide fluid is circulated between the inner and outer layers of the object to be dyed. Pretreatment is carried out at a controlled system temperature of 45 °C and a pressure of 8.5 MPa for 25 minutes to obtain the pretreated object to be dyed, and the supercritical carbon dioxide fluid in the dyeing kettle is recycled to the storage kettle through the first circulation pump to obtain the recycled supercritical carbon dioxide fluid;

[0047] The dye Disperse Red 60 and the dyeing assistant are mixed and then injected into the dye kettle.

[0048] The dyeing assistant is composed of decamethylcyclopentasiloxane and co-solvent absolute ethanol with a volume ratio of 5:2;

[0049] The mass ratio of the dye to the dyeing assistant is 3:1;

[0050] The mass ratio of the dye to the object to be dyed is 6:400.

[0051] The recycled supercritical carbon dioxide fluid in the storage kettle is injected into the dye kettle by using the second circulation pump, and the supercritical carbon dioxide fluid dissolved with the dye and the dyeing assistant is circulated between the inner and outer layers of the object to be dyed, and the system temperature is controlled at 65 °C and the pressure is 18 MPa for the first circulation dyeing for 60 minutes to obtain the fiber fabric after the first dyeing;

[0052] And the supercritical carbon dioxide fluid after dyeing in the dye kettle is recycled to the dye kettle through the second circulation pump. After adding the added dye and 20% dyeing assistant, the new polyester fiber to be dyed after wetting and pretreatment is directly subjected to the second dyeing at the same temperature, pressure and time. After the second dyeing is completed, the pressure and temperature of the dyeing system are reduced, and the dye, the dyeing assistant and carbon dioxide are separated and recovered to obtain the fiber fabric after the second dyeing;

[0053] The mass of the added dye accounts for 20% of the mass of the dye used in the first dyeing process; the mass of the added dyeing assistant accounts for 10% of the mass of the dyeing assistant used in the first dyeing process.

[0054] Example 2

[0055] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that the dyeing assistant consists of decamethylcyclopentasiloxane and anhydrous ethanol as a co-solvent with a volume ratio of 9:2.

[0056] Example 3

[0057] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that the dyeing assistant consists of decamethylcyclopentasiloxane and anhydrous ethanol as a co-solvent with a volume ratio of 13:2.

[0058] Example 4

[0059] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that the mass ratio of the dye to the object to be dyed is preferably 6:600.

[0060] Example 5

[0061] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that the mass ratio of the dye to the object to be dyed is preferably 6:800.

[0062] Comparative Example 1

[0063] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that decamethylcyclopentasiloxane is not added in both the first dyeing and the second dyeing.

[0064] Comparative Example 2

[0065] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that anhydrous ethanol is not added in both the first dyeing and the second dyeing.

[0066] Comparative Example 3

[0067] Dyeing is carried out according to the method of Example 1. The difference from Example 1 is that during the dyeing process of both the first dyeing and the second dyeing, the system temperature is 100°C, the system pressure is 20 MPa, and the dyeing time is 120 min.

[0068] The K / S values of the first dyed fiber fabrics and the second dyed fiber fabrics obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were measured at a certain wavelength by using a Datacolor SF600X colorimetric spectrometer (Datacolor, USA). The results are shown in Table 1. The columnar statistical chart of the K / S values of the first dyed fiber fabrics and the second dyed fiber fabrics obtained in Examples 1 to 5 and Comparative Examples 1 to 3 of the present invention is as Figure 2 shown.

[0069] The rubbing fastness of the above-mentioned dyed fiber fabrics was detected according to the GBT 3920-1997 standard, and the soaping fastness of the above-mentioned dyed fiber fabrics was detected according to the GBT 3921-2008 standard. The results are shown in Table 1.

[0070] Table 1 Statistical results of the dyeing effects of the dyed fiber fabrics obtained in Examples 1 to 5 and Comparative Examples 1 to 3

[0071]

[0072]

[0073] As can be seen from Table 1 and Figure 2 it can be known that, compared with Comparative Examples 1 and 2, the first dyed fiber fabrics and the second dyed fiber fabrics obtained in Examples 1 to 5 all meet the national standards, with high K / S values, a soaping fastness of 5.0 levels, and a rubbing fastness of 4.5 levels; compared with Comparative Example 3, although Comparative Example 3 increased the temperature and pressure of the dyeing system, the achieved dyeing depth and other effects are equivalent to those of Examples 1 to 5, indicating that the method provided in this application realizes ensuring high dyeing efficiency and quality at relatively lower pressure and temperature compared with the prior art.

[0074] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for dyeing using supercritical fluid, comprising the following steps: After wetting the material to be dyed with water, it is pretreated with supercritical carbon dioxide fluid to obtain the pretreated material to be dyed and the recycled supercritical carbon dioxide fluid; Mix the dye, the dye assistant and the recycled supercritical carbon dioxide fluid, and perform the first dyeing on the pretreated material to be dyed to obtain the fiber fabric after the first dyeing; The dye assistant is composed of decamethylcyclopentasiloxane and a co-solvent.

2. The method according to claim 1, characterized in that, It includes the following steps: After wetting the material to be dyed with water, wind it on a dyeing shaft and put it into a dyeing kettle; inject supercritical carbon dioxide fluid into the storage kettle, use the first circulation pump to make the supercritical carbon dioxide fluid inject into the dyeing kettle, and make the supercritical carbon dioxide fluid circulate between the inner and outer layers of the material to be dyed for pretreatment to obtain the pretreated material to be dyed, and the supercritical carbon dioxide fluid in the dyeing kettle is recycled to the storage kettle through the first circulation pump to obtain the recycled supercritical carbon dioxide fluid; Inject the mixture of the dye and the dye assistant into the dye kettle, and the dye assistant is composed of decamethylcyclopentasiloxane and a co-solvent; Inject the recycled supercritical carbon dioxide fluid in the storage kettle into the dye kettle by using the second circulation pump, and make the supercritical carbon dioxide fluid dissolved with the dye and the dye assistant circulate between the inner and outer layers of the material to be dyed for the first dyeing to obtain the fiber fabric after the first dyeing; And the supercritical carbon dioxide fluid after dyeing in the dye kettle is recycled to the dye kettle through the second circulation pump, and after adding the dye and the dye assistant, the second dyeing is directly carried out to obtain the fiber fabric after the second dyeing.

3. The method according to claim 1 or 2, characterized in that, The time of the pretreatment is 20 - 40 min, the temperature of the pretreatment is 40 - 60 °C, and the pressure of the pretreatment is 8 - 10 MPa.

4. The method according to claim 1 or 2, characterized in that, The dye is a disperse dye, and the disperse dye includes at least one of disperse red 60, disperse yellow 54, disperse orange 25, disperse blue 56, disperse violet 1, disperse red 356, and disperse blue 366.

5. The method according to claim 1 or 2, characterized in that, The co-solvent includes at least one of anhydrous ethanol, n-propanol, and butanol.

6. The method according to claim 1 or 2, characterized in that The volume ratio of decamethylcyclopentasiloxane to the co-solvent in the dye assistant is (3 - 18):

2.

7. The method according to claim 1 or 2, characterized in that The mass ratio of the dye to the dye assistant is (2 - 5):

1.

8. The method according to claim 1 or 2, characterized in that, The mass ratio of the dye to the material to be dyed is (0.1 - 10):(400 - 800).

9. The method according to claim 1 or 2, characterized in that, During the first dyeing process, the temperature of the dyeing system is 60 - 90 °C, the pressure of the dyeing system is 10 - 18 MPa, and the time of the dyeing is 60 - 110 min.

10. The method according to claim 2, characterized in that After the second dyeing is completed, it further includes: after reducing the pressure and temperature of the dyeing system, separating and recycling the dye, the dye assistant and carbon dioxide, and taking out the fiber fabric after the second dyeing.

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