Nanoscale colloidal disperse dye, preparation process and application thereof

Abstract

The application discloses a nanoscale colloidal dispersion dye and a preparation process and application thereof, and relates to the field of printing and dyeing materials.The preparation process comprises the following steps: step (1), preparing a nanoscale colloidal suspension by a reverse solvent precipitation method; step (2), preparing a modified nanoscale colloidal suspension; and step (3), preparing the nanoscale colloidal dispersion dye by freeze drying.The nanoscale colloidal dispersion dye has good dispersibility, a light response effect and the ability to control the release of a dyeing agent, and the inkjet ink prepared from the nanoscale colloidal dispersion dye has the light-controlled release characteristic, and the color development of a pattern after printing can be controlled.

Description

Technical Field

[0001] This invention relates to the field of printing and dyeing materials, specifically to a nanoscale colloidal disperse dye and its preparation process and application. Background Technology

[0002] Disperse dyes are widely used as colorants in sublimation digital printing inkjet inks and textile direct-to-garment inks. However, the production of traditional disperse dyes generates significant pollution, resulting in coarse dye particles and poor dispersibility, leading to suboptimal coloring effects. To address these issues, existing research has developed disperse dye nanocapsules for sublimation digital printing inkjet inks. These nanocapsules use disperse dyes as the core material and styrene monomers, acrylate monomers, and N-(isobutoxymethyl)acrylamide monomers as wall materials, with the addition of hydrophobic agents, initiators, emulsifiers, and other substances, prepared via a free radical polymerization mechanism. The resulting disperse dye nanocapsules are spherical with an average particle size of 60–300 nm, a dye coating weight greater than 2%, a gelation rate less than 0.8%, and exhibit high centrifugal and ionic stability. While this method achieves good dispersion, the preparation process is complex and its functionality is limited. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a nanoscale colloidal disperse dye, its preparation process, and its application. The invention prepares a nanoscale colloidal disperse dye with good dispersibility, photoresponsive properties, and the ability to control dye release. Inkjet inks made from this nanoscale colloidal disperse dye exhibit photocontrolled release characteristics, enabling controllable color development of printed patterns.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] This scheme proposes a method for preparing nanoscale colloidal disperse dyes, including the following steps:

[0006] Step (1): Dissolve 50-80 parts by weight of hydrophobic dye in 150-200 parts by weight of lipophilic solvent to obtain a dye solution; slowly inject the obtained dye solution into 150-200 parts by weight of aqueous solution to obtain a mixture; dialyze the mixture with deionized water to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution with a mass fraction of 0.2%-0.5% stabilizer.

[0007] Step (2): Add 0.3-0.6 parts by weight of amphoteric photoresponsive agent to 80-120 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under ultraviolet light until the reaction is complete to obtain modified nanocolloid suspension;

[0008] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 7.5-9.5, add 3-5 parts by weight of protective agent, stir and disperse, and then freeze dry to obtain nano-colloid disperse dye.

[0009] The preparation method of this scheme has the following characteristics:

[0010] 1. Preparation of nanocrystalline nuclei via antisolvent precipitation. A solvent system is constructed using an lipophilic solvent as the good solvent and deionized water as the antisolvent. Hydrophobic disperse dyes are dissolved in the lipophilic solvent and then injected into an aqueous solution containing a stabilizer. The dye molecules rapidly precipitate using solvent diffusion kinetics, thereby generating 50nm-100nm nanocrystalline nuclei. The stabilizer is an amphiphilic block copolymer; its hydrophobic ends adsorb onto the surface of the dye particles, while its hydrophilic ends move towards the aqueous layer, inhibiting particle aggregation through steric hindrance. After dialysis purification, free stabilizer is removed, resulting in a nanocolloidal suspension. This method for preparing nanocolloidal suspensions offers advantages in terms of energy efficiency and environmental friendliness compared to traditional mechanical ball milling.

[0011] 2. Modification of nanocolloid particles in nanocolloid suspensions using photoresponsive molecules. The hydrophobic ends of amphoteric photoresponsive molecules can adsorb onto the surface of dye particles, while the hydrophilic ends combine with water to form a dynamic coating layer. By irradiating with ultraviolet light, the molecular chains of the hydrophilic ends are altered, causing them to curl up and adhere closely to the particle surface, thereby enhancing the interfacial binding force and endowing the colloidal light-controlled release function.

[0012] Preferably, the hydrophobic dye in step (1) is an anthraquinone derivative dye, such as Disperse Red, Disperse Blue, etc.

[0013] Preferably, the lipophilic solvent in step (1) is DMF or acetone.

[0014] Preferably, the stabilizer mentioned in step (1) is one of polyoxyethylene-polyoxypropylene block copolymer, PVP, or PEG. Polyoxyethylene-polyoxypropylene block copolymer is a mature commercial product, and F-127, F-68, etc. can be selected.

[0015] Preferably, the process of slowly injecting the prepared dye solution into 150-200 parts by weight of aqueous solution in step (1) is as follows: the initial temperature is 10℃-15℃, the temperature is increased to 30℃-40℃ at a rate of 0.01℃ / s-0.03℃ / s, and the temperature is maintained; the gas pressure is 0.95atm-0.98atm; and the injection rate is 0.05-0.2 parts by weight / second.

[0016] The dispersion of nanoscale colloidal particles can be further improved by utilizing the precipitation of saturated carbon dioxide solution. This method controls the gas-liquid interface through carbon dioxide precipitation, creating a template effect. Combined with the presence of a stabilizer, this more effectively promotes the generation and dispersion of uniform nanocrystal nuclei. Since the solubility of saturated carbon dioxide varies with temperature and pressure, and solution disturbance also leads to its precipitation, this method strictly controls the heating rate, gas pressure, and injection rate, ensuring that the precipitated carbon dioxide exists in the mixture in the form of micro- and nano-bubbles.

[0017] Preferably, the amphoteric photoresponsive agent mentioned in step (2) is azobenzene-polyethylene glycol, prepared by the following method:

[0018] Step (2-1): Dissolve 1-2 parts by weight of phenylazobenzoic acid in 20-30 parts by weight of DMF in the dark to obtain solution A;

[0019] Step (2-2): Add 0.5-0.6 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.3-0.5 parts by weight of N-hydroxysuccinimide to solution A, stir and react to generate phenylazobenzoic acid-N-hydroxysuccinimide ester solution, thus obtaining solution B;

[0020] Steps (2-3): Dissolve 5-6 parts by weight of terminally aminated polyethylene glycol in 20-30 parts by weight of DMF to obtain solution C. Then slowly add solution C to solution B and react in an anaerobic environment for 20-30 hours. Adjust the pH to 4-6 to obtain solution D.

[0021] Steps (2-4): DMF in solution D is evaporated, followed by dialyzing with deionized water and freeze-drying to obtain azobenzene-polyethylene glycol.

[0022] The azophenyl group in azobenzene-polyethylene glycol undergoes a cis-trans configurational transition under 360nm-380nm ultraviolet light irradiation, resulting in a change in molecular polarity and disrupting the interaction between the dye and colloidal particles. In this scheme, the use of azobenzene-polyethylene glycol modification enables the nanocolloidal particles to exhibit good photoresponsiveness, achieving photocontrolled dye release. In steps (2-3), pH adjustment is achieved using glacial acetic acid to neutralize unreacted N-hydroxysuccinimide.

[0023] Preferably, in steps (2-3), the terminally aminated polyethylene glycol has an average molecular weight of 2000 Daltons and a PDI < 1.1.

[0024] Preferably, in step (2-4), the temperature at which DMF is evaporated from solution D is 40℃-60℃; the freeze-drying process is to pre-freeze at -50℃--30℃ for 4h-6h, and then freeze-dry at -50℃--30℃ under conditions of 0.1Pa-0.5Pa.

[0025] Preferably, the ultraviolet light source in step (2) is 360nm-370nm.

[0026] Preferably, the protective agent in step (3) is alginate, and the reagent used to adjust the pH is sodium citrate.

[0027] Preferably, the freeze-drying process in step (3) involves pre-freezing at -80°C to -50°C for 4-6 hours, followed by adjusting the air pressure to 0.1Pa to 0.2Pa, and then freeze-drying at -80°C to -50°C.

[0028] This solution also proposes a method for preparing nanoscale colloidal disperse dyes using the above-mentioned method, which can be used to prepare inks.

[0029] The nanoscale colloidal disperse dyes described in this solution can be used to prepare printer inks, direct-to-garment inks for fabrics, digital printing inks, etc.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The nano-colloidal disperse dye prepared by this method has good dispersibility and photoresponsiveness, and can control the release of dye. The inkjet ink made from it has photocontrolled release characteristics, which can realize controllable color development of the printed pattern.

[0032] 2. Compared with traditional mechanical grinding processes, this solution reduces equipment requirements, energy consumption, and simplifies the process. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the embodiments and comparative examples of this scheme, the nitrogen-based benzene-polyethylene glycol used was prepared by the following method:

[0035] Step (2-1): Dissolve 2 parts by weight of phenylazobenzoic acid in 25 parts by weight of DMF in the dark to obtain solution A;

[0036] Step (2-2): Add 0.55 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.5 parts by weight of N-hydroxysuccinimide to solution A, stir and react to generate phenylazobenzoic acid-N-hydroxysuccinimide ester solution, thus obtaining solution B;

[0037] Steps (2-3): Dissolve 6 parts by weight of terminally aminated polyethylene glycol with an average molecular weight of 2000 Daltons and a PDI of 0.8 in 30 parts by weight of DMF to obtain solution C. Then slowly add solution C to solution B and react for 24 hours under nitrogen protection. Adjust the pH to 5.5 to obtain solution D.

[0038] Steps (2-4): DMF in solution D was evaporated at 50°C, followed by dialyzing with deionized water, then pre-freezing at -30°C for 5 hours, and then freeze-drying at -30°C and 0.3 Pa to obtain azobenzene-polyethylene glycol.

[0039] Example 1

[0040] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0041] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.4%; the process of slowly injecting the obtained dye solution into 170 parts by weight of an aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.02℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 0.1 parts by weight / second;

[0042] Step (2): Add 0.5 parts by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0043] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0044] Example 2

[0045] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0046] Step (1): Dissolve 80 parts by weight of Disperse Red 60 in 200 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 200 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.5%; the process of slowly injecting the obtained dye solution into 200 parts by weight of an aqueous phase solution is as follows: the initial temperature is 15℃, the temperature is increased to 40℃ at a rate of 0.03℃ / s and the temperature is maintained; the gas pressure is 0.98 atm; the injection rate is 0.2 parts by weight / second;

[0047] Step (2): Add 0.6 parts by weight of azobenzene-polyethylene glycol to 120 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0048] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 5 parts by weight of alginic acid, stir and disperse, pre-freeze at -50℃ for 6 hours, then adjust the air pressure to 0.2Pa and freeze dry to obtain nano-colloidal disperse dye.

[0049] Example 3

[0050] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0051] Step (1): Dissolve 50 parts by weight of Disperse Red 60 in 150 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 150 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.2%; the process of slowly injecting the obtained dye solution into 150 parts by weight of an aqueous phase solution is as follows: the initial temperature is 10℃, the temperature is increased to 30℃ at a rate of 0.01℃ / s and the temperature is maintained; the gas pressure is 0.98 atm; the injection rate is 0.05 parts by weight / second;

[0052] Step (2): Add 0.3 parts by weight of azobenzene-polyethylene glycol to 80 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0053] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 3 parts by weight of alginic acid, stir and disperse, pre-freeze at -80℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloid disperse dye.

[0054] Comparative Example 1

[0055] The difference from Example 1 is that the aqueous phase is deionized water;

[0056] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0057] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of deionized water to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the water phase is 0.4% by mass of F-127 deionized water; the process of slowly injecting the obtained dye solution into 170 parts by weight of deionized water is as follows: initial temperature 13℃, heating to 35℃ at a rate of 0.02℃ / s and maintaining the temperature; gas pressure 0.96 atm; injection rate 0.1 parts by weight / second;

[0058] Step (2): Add 0.5 parts by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0059] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0060] Comparative Example 2

[0061] The difference from Example 1 is that F-127 is used in excess;

[0062] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0063] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.8%; the process of slowly injecting the obtained dye solution into 170 parts by weight of an aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.02℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 0.1 parts by weight / second;

[0064] Step (2): Add 0.5 parts by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0065] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0066] Comparative Example 3

[0067] The difference from Example 1 is that there are too few F-127s;

[0068] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0069] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.1%; the process of slowly injecting the obtained dye solution into the 170 parts by weight of the aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.02℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 0.1 parts by weight / second;

[0070] Step (2): Add 0.5 parts by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0071] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0072] Comparative Example 4

[0073] The difference from Example 1 is that in step (1), the process of injecting the dye solution into the aqueous phase solution is too violent;

[0074] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0075] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.4%; the process of slowly injecting the obtained dye solution into 170 parts by weight of an aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.5℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 1 part by weight / second;

[0076] Step (2): Add 0.5 parts by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0077] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0078] Comparative Example 5

[0079] The difference from Example 1 is that azobenzene-polyethylene glycol was not added.

[0080] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0081] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.4%; the process of slowly injecting the obtained dye solution into 170 parts by weight of an aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.02℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 0.1 parts by weight / second;

[0082] Step (2): Place 100 parts by weight of the nanocolloid suspension under a 365nm ultraviolet light source for irradiation until the reaction is complete to obtain the modified nanocolloid suspension;

[0083] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0084] Comparative Example 6

[0085] The difference from Example 1 is that an excessive amount of azobenzene-polyethylene glycol was added;

[0086] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0087] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.4%; the process of slowly injecting the obtained dye solution into 170 parts by weight of an aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.02℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 0.1 parts by weight / second;

[0088] Step (2): Add 1 part by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension.

[0089] Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, add 4 parts by weight of alginic acid, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloidal disperse dye.

[0090] Comparative Example 7

[0091] The difference from Example 1 is that alginic acid was not added;

[0092] A method for preparing nanoscale colloidal disperse dyes includes the following steps:

[0093] Step (1): Dissolve 65 parts by weight of Disperse Red 60 in 170 parts by weight of DMF to obtain a dye solution; slowly inject the obtained dye solution into 170 parts by weight of an aqueous phase solution to obtain a mixture; dialyze the mixture with 4 times the volume of deionized water for 16 hours to obtain a nanocolloid suspension; the aqueous phase is a saturated carbonate aqueous solution of F-127 with a mass fraction of 0.4%; the process of slowly injecting the obtained dye solution into 170 parts by weight of an aqueous phase solution is as follows: the initial temperature is 13℃, the temperature is increased to 35℃ at a rate of 0.02℃ / s and the temperature is maintained; the gas pressure is 0.96 atm; the injection rate is 0.1 parts by weight / second;

[0094] Step (2): Add 0.5 parts by weight of azobenzene-polyethylene glycol to 100 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under a 365nm ultraviolet light source until the reaction is complete to obtain modified nanocolloid suspension;

[0095] Step (3): Take 100 parts by weight of the modified nanocolloid suspension, adjust the pH to 8 with sodium citrate, stir and disperse, pre-freeze at -60℃ for 4 hours, then adjust the air pressure to 0.1 Pa, freeze dry at -50℃ to obtain nano-colloid disperse dye.

[0096] Performance testing:

[0097] 1. Average particle size: The average particle size of the nanodyes was determined by dynamic light scattering (DLS);

[0098] 2. Zeta potential: The surface charge of dye particles is measured using a zeta potential meter. The higher the absolute value, the more stable the dispersion system.

[0099] 3. Dispersion uniformity test: The dye is redispersed in water, and the particle distribution uniformity is assessed by turbidity method;

[0100] 4. Inkjet ink characteristic testing: By weight, inkjet ink is prepared using 20 parts of nano-grade colloidal disperse dye, 50 parts of deionized water, 10 parts of glycerol, 6 parts of ethylene glycol, 1 part of surfactant, 0.2 parts of antioxidant, and 0.05 parts of antibacterial agent. The color intensity and uniformity are tested according to ISO 9706 standard, ΔE1, which should be less than 1.5. For light response characteristic testing, the printed pattern is locally irradiated with 365nm ultraviolet light, and the color development sensitivity is tested. The color difference change before and after irradiation is compared using a spectrophotometer, and ΔE2 should be greater than 3.

[0101] The test results are shown in Table 1.

[0102] Table 1

[0103]

[0104] The results above show that the nanoscale colloidal disperse dyes prepared in Examples 1 to 3 have smaller average particle size, better dispersibility, and ΔE1 and ΔE2 compared with the nanoscale colloidal disperse dyes prepared in Comparative Examples 1 to 7.

[0105] The main difference between Comparative Example 1 and Example 1 is that the aqueous phase of Comparative Example 1 is deionized water, which has no microbubble template effect. Therefore, the dye molecules cannot control the nucleation kinetics through carbon dioxide precipitation. At the same time, the F-127 stabilizer has no interfacial directional adsorption effect compared to Example 1, which leads to the particle coarsening to 184.6 nm, the Zeta potential decreases, and directly causes ΔE1 and ΔE2 to deteriorate.

[0106] The difference between Comparative Example 2 and Example 1 is that an excess of F-127 forms micelles in the aqueous phase, competing with dye particles for adsorption, resulting in an uneven coating layer and a coarser average particle size of the nanoscale colloidal particles, ultimately leading to an increase in ΔE1 and a decrease in ΔE2. The difference between Comparative Example 3 and Example 1 is that an insufficient amount of F-127 results in a weak steric hindrance effect, allowing Ostwald curing to dominate and significantly increasing the average particle size of the nanoscale colloidal particles.

[0107] The difference between Comparative Example 4 and Example 1 is that in step (1), the process of injecting the dye solution into the aqueous phase solution is too violent, resulting in excessive local carbon dioxide supersaturation, bubble merging, which makes the solution stability worse, generating multi-sized crystal nuclei and merging through collision, ultimately increasing the average particle size, worsening the dispersibility, and worsening ΔE1 and ΔE2.

[0108] The difference between Comparative Example 5 and Example 1 is that azobenzene-polyethylene glycol was not added, which made the surface charge shielding effect worse than that of Example 1, resulting in the aggregation of nanoscale colloidal particles and the absence of photoresponse characteristics.

[0109] The difference between Comparative Example 6 and Example 1 is that an excessive amount of azobenzene-polyethylene glycol was added, which would hinder the release of dye and cause secondary aggregation due to molecular chain entanglement, resulting in an increase in the average particle size of the nanoscale colloidal particles and a deterioration of ΔE1.

[0110] The difference between Comparative Example 7 and Example 1 is that alginic acid was not added, which causes the nano-sized colloidal particles to collapse and aggregate due to capillary forces, resulting in a surge in the average particle size of the nano-sized colloidal particles.

[0111] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for preparing nanoscale colloidal disperse dyes, characterized in that, Includes the following steps: Step (1): Dissolve 50-80 parts by weight of Disperse Red 60 in 150-200 parts by weight of an oleophilic solvent to obtain a dye solution; slowly inject the obtained dye solution into 150-200 parts by weight of an aqueous phase solution. The process is as follows: the initial temperature is 10℃-15℃, and the temperature is increased to 30℃-40℃ at a rate of 0.01℃ / s-0.03℃ / s and maintained; the gas pressure is 0.95atm-0.98atm; the injection rate is 0.05-0.2 parts by weight / second to obtain a mixture; dialyze the mixture with deionized water to obtain a nanocolloid suspension; the aqueous phase solution is a saturated carbonated aqueous solution of F-127 with a mass fraction of 0.2%-0.5%; Step (2): Add 0.3-0.6 parts by weight of azobenzene-polyethylene glycol to 80-120 parts by weight of nanocolloid suspension, stir and disperse, and then irradiate under ultraviolet light until the reaction is complete to obtain modified nanocolloid suspension; Step (3): Take 100 parts by weight of modified nanocolloid suspension, adjust the pH to 7.5-9.5, add 3-5 parts by weight of alginic acid, stir and disperse, and then freeze dry to obtain nano-colloidal disperse dye.

2. The method for preparing nanoscale colloidal disperse dyes as described in claim 1, characterized in that, The lipophilic solvent mentioned in step (1) is DMF or acetone.

3. The method for preparing nanoscale colloidal disperse dyes as described in claim 1, characterized in that, The ultraviolet light source in step (2) is 360nm-370nm.

4. The method for preparing nanoscale colloidal disperse dyes as described in claim 1, characterized in that, The reagent used to adjust the pH is sodium citrate.

5. The method for preparing nanoscale colloidal disperse dyes as described in claim 1, characterized in that, The freeze-drying process described in step (3) involves pre-freezing at -80℃ to -50℃ for 4-6 hours, then adjusting the air pressure to 0.1 Pa to 0.2 Pa, and freeze-drying at -80℃ to -50℃.

6. A nanoscale colloidal disperse dye prepared by the method for preparing nanoscale colloidal disperse dyes as described in any one of claims 1-5.

7. The nanoscale colloidal disperse dye as described in claim 6 is used in the preparation of inks.

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