Method for dyes screening used in supercritical carbon dioxide dyeing and system thereof

Abstract

A method for screening dyes for supercritical carbon dioxide dyeing is provided, comprising: contacting a test dye with carbon dioxide at a predetermined pressure and temperature to achieve phase equilibrium and form a mixture; removing the mixture at a constant flow rate under a quantitative gas flow; introducing the mixture into a solvent to displace the test dye into the solvent, forming a solution containing the test dye; detecting the absorbance of the solution and calculating the solubility of the test dye by comparing it with a pre-established concentration calibration curve of the test dye; and establishing a correlation between the solubility of the test dye and the dyeing strength value obtained by the test dye on the fabric, as a basis for screening whether the test dye meets the requirements for supercritical carbon dioxide dyeing. A screening system is also provided to achieve rapid prediction of dyeability before fabric dyeing.

Claims

1. A method for screening dyes for supercritical carbon dioxide dyeing, comprising the following steps: performing a supercritical carbon dioxide solubility test, contacting a test dye with carbon dioxide at a predetermined pressure and a predetermined temperature, causing the test dye to dissolve and reach phase equilibrium, forming a mixture containing the test dye and the carbon dioxide; draining the mixture at a predetermined flow rate while maintaining a certain amount of gas; introducing the mixture into a solvent for displacement, causing the test dye to transfer into the solvent, forming a solution containing the test dye; detecting the absorbance of the solution, and calculating the solubility of the test dye using a pre-established test dye concentration calibration curve; and establishing a correlation between the solubility of the test dye and a dyeing strength value (K / S) obtained by the test dye on a fabric, as a screening criterion for whether the test dye meets the requirements for supercritical carbon dioxide dyeing.

2. The screening method as described in claim 1, wherein the screening criterion includes that the solubility of the dye used for supercritical carbon dioxide staining is greater than or equal to 1 × 10⁻⁶ moles of dye / moles of carbon dioxide.

3. The screening method as described in claim 1, wherein the screening criteria further include that the dye used for supercritical carbon dioxide staining has a continuous methylene signal in the range of chemical shift from 0.80 ppm to 1.80 ppm in nuclear magnetic resonance spectroscopy analysis, and that the number of carbon atoms in the long-chain alkyl substituents is from 2 to 20.

4. The screening method as described in claim 1, wherein in the step of performing the supercritical carbon dioxide solubility test, the predetermined pressure is 15 MPa to 30 MPa and the predetermined temperature is 100°C to 120°C.

5. The screening method as described in claim 1, wherein in the step of maintaining the quantitative gas conditions, the preset flow rate is from 0.5 mL / min to 5.0 mL / min.

6. The screening method as claimed in claim 1, wherein in the step of introducing the fluid of the mixture into the solvent for displacement, the solvent comprises ethanol, isopropanol, acetone, tetrahydrofuran, dimethyl sulfoxide, or any combination thereof.

7. The screening method as described in claim 1, wherein the step of detecting the absorbance of the solution includes detecting the absorbance of the solution by spectrophotometry.

8. The screening method as described in claim 1, wherein in the step of detecting the absorbance of the solution, the test dye concentration check curve is formed by a plurality of concentrations and a plurality of corresponding absorbances of the test dye obtained in the solvent.

9. The screening method as described in claim 8, wherein the solubility of the test dye is calculated based on the concentration of the test dye trapped in the solvent, combined with an outflow rate and an outflow time.

10. The screening method as described in claim 1, wherein in the step of establishing the solubility of the dye to be tested, the dyeing strength value is obtained by dyeing the fabric with the dye to be tested under a specific supercritical dyeing condition.

11. The screening method as described in claim 10, wherein the specific supercritical staining conditions are 25 MPa, 100°C to 120°C and 60 minutes.

12. The screening method as described in claim 1, wherein the fabric comprises polypropylene, polyethylene terephthalate, polyethylene, or a combination thereof.

13. A system for screening dyes for supercritical carbon dioxide dyeing, comprising: a control module configured to contact a test dye with carbon dioxide at a predetermined pressure and a predetermined temperature, thereby achieving dissolution equilibrium of the test dye under supercritical carbon dioxide conditions through constant pressure equilibrium, and forming a mixture comprising the test dye and the carbon dioxide; a displacement module configured to discharge the fluid of the mixture through constant-rate flow and introduce a solvent for displacement, forming a solution comprising the test dye; a parameter calculation module configured to calculate the solubility of the test dye and the dyeing strength value (K / S) obtained by the test dye on the fabric to obtain a control relationship; and a screening module configured to use the control relationship as a screening criterion for whether the test dye meets the requirements for dyeing with supercritical carbon dioxide.

14. The system as claimed in claim 13, wherein the control module comprises: a boosting module configured to boost the carbon dioxide to the predetermined pressure; and a temperature control module configured to contact the carbon dioxide, which has been boosted to the predetermined pressure, with the dye to be tested at the predetermined temperature.

15. The system as claimed in claim 14, wherein the boosting module includes a high-pressure pump; and the temperature control module includes a heater and a dyeing vat, wherein the heater is disposed between and connected to the high-pressure pump and the dyeing vat to allow the dye to be tested and the carbon dioxide to reach a dissolution equilibrium in the dyeing vat and form the mixture.

16. The system of claim 15, wherein the displacement module comprises: a back pressure regulating valve configured to discharge fluid of the mixture by a constant flow rate; and a dye collection bottle, wherein one end of the back pressure regulating valve is in communication with the dye vat and the other end of the back pressure regulating valve is in communication with the dye collection bottle to introduce the mixture into the solvent for displacement, forming the solution containing the dye to be tested.

17. The system as claimed in claim 14, wherein the control module further includes an environmental module configured to supply the carbon dioxide to the booster module, wherein the carbon dioxide is liquid carbon dioxide.

18. The system as described in claim 13, wherein the screening criteria further include that the dye has a continuous methylene signal in the range of chemical shift from 0.80 ppm to 1.80 ppm in nuclear magnetic resonance spectroscopy analysis, and that the long-chain alkyl substituents have 2 to 20 carbon atoms.

19. The system as claimed in claim 13, wherein the parameter calculation module is further configured to detect an absorbance of the solution and calculate the solubility of the dye to be tested against a pre-established calibration curve for the concentration of the dye to be tested.

20. The system as claimed in claim 19, wherein the solubility of the test dye is calculated based on the concentration of the test dye trapped in the solvent, combined with an outflow rate and an outflow time.

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