High water washing and sunlight resistant inkjet printing disperse dye and preparation method thereof

Abstract

This invention relates to the field of dyes and textile printing technology, and discloses a high wash fastness and lightfastness inkjet printing disperse dye and its preparation method. The disperse dye comprises, by mass percentage, disperse dye powder, an enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant, a hydroxyl-terminated silane coupling agent, a humectant, and deionized water. In preparation, enzymatically hydrolyzed lignin is ring-opened polymerized with polyetheramine to prepare a hyperbranched dispersant, which is then pre-dispersed with the dye powder and milled. During milling, the hydroxyl-terminated silane coupling agent is added dropwise to form a siloxane cross-linked network on the surface of the dye particles, with the hyperbranched polymer cavities externally coated by hydrogen bonds. This method changes the conventional physical adsorption and fixation method of dispersants, solves the problem of secondary dye aggregation and pore blockage caused by dispersant desorption under high-frequency shear conditions, eliminates the obstruction of free dispersant to the diffusion of dye into the fiber interior, and allows unfixed dye to be normally removed during the washing stage, thereby improving the wash fastness of the fabric.

Description

Technical Field

[0001] This invention relates to the field of dyes and textile printing technology, and discloses a high wash-resistance, sun-resistant inkjet printing disperse dye and its preparation method. Background Technology

[0002] Existing inkjet printing disperse dyes typically employ linear dispersants such as naphthalenesulfonic acid formaldehyde condensate to maintain system stability. The conventional preparation process involves mixing the disperse dye powder with the aforementioned linear dispersant in deionized water, followed by milling the dye particles to the nanoscale using a sand mill. During this process, the linear dispersant molecules adsorb onto the surface of the dye particles through electrostatic attraction or van der Waals forces. The steric hindrance formed by molecular chain extension and double-layer repulsion prevent the particles from approaching each other and agglomerating, thus obtaining an ink system that meets the requirements of inkjet printing.

[0003] In the system described above, which relies on the physical adsorption of linear dispersants for stability, the linear dispersant molecular chains undergo conformational changes and steric hindrance fails when subjected to high-frequency mechanical shear forces at the inkjet printer nozzle. This leads to the desorption of the dispersant from the dye particle surface. The desorbed dye particles, lacking the repulsive barrier, re-aggregate into micron-sized particles, clogging the nozzle. The desorbed linear dispersant then migrates to the polyester fiber surface, hindering the diffusion of dye molecules into the fiber interior during the high-temperature steam fixation stage. This results in severe bleeding of unfixed dye during the washing stage, causing a deterioration in wash fastness. Summary of the Invention

[0004] In view of the shortcomings of existing inkjet printing disperse dyes which use a stable system of physical adsorption of linear dispersants, such as the easy desorption of dispersants from the surface of dye particles under high-frequency shearing, secondary agglomeration of dye particles clogging the nozzles, and free dispersants hindering the diffusion of dye into the interior of polyester fibers, resulting in the deterioration of the wash fastness of printed fabrics, this invention provides a high wash fastness and sun fastness inkjet printing disperse dye and its preparation method.

[0005] To address the aforementioned technical problems, this invention provides a high washability and sun-resistance disperse dye for inkjet printing. By mass percentage, the disperse dye comprises the following components: 5%-15% disperse dye powder; 2%-8% enzymatic hydrolyzed lignin-based hyperbranched polymer dispersant; 0.5%-3% terminal hydroxyl silane coupling agent; 10%-20% humectant; 0.1%-0.5% bactericide; and 53.5%-82.4% deionized water. The enzymatic hydrolyzed lignin-based hyperbranched polymer dispersant is a hyperbranched polymer with a three-dimensional topological structure synthesized from enzymatically hydrolyzed lignin as a starting material through ring-opening polymerization grafting polyetheramine segments. The terminal hydroxyl silane coupling agent coats the surface of the disperse dye powder and forms a siloxane crosslinking network, with the cavity structure of the enzymatic hydrolyzed lignin-based hyperbranched polymer dispersant covering the outside of the siloxane crosslinking network.

[0006] In practice, the active silanol groups of the hydroxyl-terminated silane coupling agent form a dense and continuous siloxane cross-linked network in situ on the surface of the nanoscale disperse dye powder through a dehydration condensation reaction. This network is firmly anchored to the dye particle surface through chemical bonding and hydrogen bonding, and will not desorb under high-frequency shearing. The enzymatically hydrolyzed lignin-based hyperbranched polymer has a three-dimensional topological cavity structure, which can stably bind to the active hydroxyl groups on the surface of the siloxane cross-linked network through intermolecular hydrogen bonds, completely encapsulating the cross-linked network inside the cavity. Its three-dimensional topological structure provides a steric hindrance effect that is much stronger than that of linear dispersants, and will not cause molecular chain conformational inversion and desorption under high-frequency shearing, effectively preventing secondary agglomeration of dye particles. At the same time, the siloxane cross-linked network can isolate external moisture and ultraviolet rays from eroding dye molecules, improving the dye's wash fastness and sun fastness. The hyperbranched polymer coating layer will not be released to the polyester fiber surface during the high-temperature steam fixation stage, and will not hinder the diffusion of dye molecules into the fiber interior, allowing the unfixed dye to fall off normally during the washing stage, significantly improving the wash fastness of printed fabrics.

[0007] Furthermore, in the above technical solution, the molecular weight of the enzymatically hydrolyzed lignin is 1000-3000 Daltons, the molecular weight of the polyetheramine is 400-2000 Daltons, the mass ratio of the enzymatically hydrolyzed lignin to the polyetheramine is 1:2 to 1:5, and the degree of branching of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant is 0.3-0.6.

[0008] In practice, limiting the molecular weight range of the enzymatically hydrolyzed lignin ensures that it has sufficient active sites for the grafting reaction of polyetheramine segments, while avoiding excessively high molecular weight that would result in an excessively large polymer cavity size, preventing it from forming a matching coating with the siloxane crosslinking network. Matching the molecular weight of the polyetheramine with the feed mass ratio allows for precise control of the branching degree and cavity size of the hyperbranched polymer. A branching degree of 0.3-0.6 allows the polymer to form a stable three-dimensional cavity structure, ensuring both the coating effect on the internal siloxane crosslinking network and providing sufficient steric hindrance to effectively inhibit the aggregation of dye particles.

[0009] Furthermore, in the above technical solution, the hydroxyl-terminated silane coupling agent is selected from the product of hydrolysis modification of γ-glycidoxypropyltrimethoxysilane, or from bis-(γ-triethoxysilylpropyl)-tetrasulfide, and the molecular structure of the hydroxyl-terminated silane coupling agent contains at least two silanol groups.

[0010] In practice, the design of at least two silanol groups in the molecular structure ensures that when the silane coupling agent undergoes a cross-linking reaction on the surface of the dye particles, it can form a continuous and dense three-dimensional siloxane cross-linking network, avoiding the defect that a single silanol group can only be grafted at one end and cannot form a cross-linking structure. The two selected silane coupling agents can generate sufficient active silanol groups after hydrolysis, which can not only form hydrogen bonds with the polar groups on the surface of the dye particles to achieve anchoring, but also condense with each other to form a stable cross-linking network, significantly improving the shear resistance and water resistance of the coating layer.

[0011] Furthermore, in the above technical solution, the disperse dye powder is a single-component anthraquinone structure disperse dye or a single-component heterocyclic structure disperse dye, the average particle size of the disperse dye powder before coating is 50-150 nanometers, and the crystal morphology of the disperse dye powder is β crystal form.

[0012] In practice, single-component anthraquinone or heterocyclic disperse dyes have excellent lightfastness. β-crystal dyes have stable crystal structures and are less prone to crystal transformation during grinding and storage, thus avoiding particle agglomeration caused by crystal transformation. An initial particle size of 50-150 nanometers ensures that dye particles can form a uniform nanoscale dispersion system during subsequent grinding and coating processes, meeting the nozzle requirements for inkjet printing, while avoiding the problem of excessively rapid dye molecule migration and decreased washability caused by excessively small particle size.

[0013] Furthermore, in the above technical solution, the humectant is a mixture of diethylene glycol and 2-pyrrolidone in a mass ratio of 3:1 to 1:1, the humectant forms a homogeneous solution system with the deionized water, and the amount of humectant added is used to adjust the surface tension of the disperse dye at 25°C to 30-40 mN / m.

[0014] In practice, the combination system of diethylene glycol and 2-pyrrolidone can form a stable homogeneous solution with deionized water, which has the dual functions of moisturizing and surface tension regulation. Diethylene glycol can reduce the evaporation rate of ink and prevent ink from drying and clogging at the nozzle. 2-pyrrolidone can improve the compatibility and dispersion stability of the dye system. When the two are combined in a specific ratio, the surface tension of the ink can be precisely controlled to the inkjet adaptation range of 30-40mN / m, ensuring the ink jetting stability and droplet formation effect at the nozzle.

[0015] Furthermore, in the above technical solution, the thickness of the siloxane crosslinking network is 5-20 nanometers, and the thickness of the coating layer of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant outside the siloxane crosslinking network is 10-50 nanometers. The coating layer and the siloxane crosslinking network are interconnected by hydrogen bonds.

[0016] In practice, a 5-20 nm siloxane crosslinking network thickness ensures dense coating of dye particles, effectively isolating them from water and ultraviolet radiation, without excessively increasing particle size and affecting inkjet performance. A 10-50 nm hyperbranched polymer coating layer provides sufficient steric hindrance to resist high-frequency shear forces and particle aggregation during storage. The two are connected by hydrogen bonds, which have a stronger binding force than simple physical adsorption, making it less prone to coating layer desorption under high-frequency shear conditions and ensuring the long-term dispersion stability of the dye system.

[0017] To address the aforementioned technical problems, this invention also provides a method for preparing a high wash-resistance, lightfast inkjet printing disperse dye, used to prepare any of the disperse dyes described above. The preparation method includes the following steps: Step S1, enzymatically hydrolyzed lignin and polyetheramine undergo ring-opening polymerization in the presence of a catalyst to synthesize an enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant; Step S2, the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant and disperse dye powder are added to deionized water for pre-dispersion to obtain a mixed slurry; Step S3, the mixed slurry is fed into a sand mill for deep grinding; Step S4, during the deep grinding process, a terminal hydroxyl silane coupling agent is added dropwise to cause the terminal hydroxyl silane coupling agent to undergo a cross-linking reaction on the surface of the dye particles; Step S5, the ground slurry is mixed evenly with a humectant and a bactericide, and after filtration and degassing, the high wash-resistance, lightfast inkjet printing disperse dye is obtained.

[0018] In specific implementation, step S1 involves a ring-opening polymerization reaction to graft polyetheramine segments onto the active hydroxyl sites of enzymatically hydrolyzed lignin, constructing a hyperbranched polymer with a three-dimensional topological cavity structure, providing a stable sterically hindered matrix for subsequent dye particle coating; step S2's pre-dispersion ensures that the dye powder and hyperbranched dispersant are fully wetted and uniformly mixed in the aqueous phase, providing a uniformly dispersed slurry system for subsequent deep grinding and preventing local agglomeration during the grinding process; step S3's deep grinding pulverizes the dye powder to the nanoscale, while simultaneously opening up the dye particles. The active polar sites on the surface provide binding sites for the anchoring of the terminal hydroxyl silane coupling agent; in step S4, the terminal hydroxyl silane coupling agent is added dropwise at a uniform rate in the grinding shear field, so that the silane coupling agent undergoes in-situ hydrolysis and cross-linking on the surface of the nano dye particles, simultaneously achieving the ultrafineness of the dye particles and the coating of the surface siloxane cross-linking network, avoiding particle agglomeration caused by subsequent secondary coating; in step S5, the application performance of the ink is controlled by compounding humectants and bactericides, and large particle agglomerates and bubbles in the system are removed by filtration and defoaming, ensuring the inkjet compatibility and storage stability of the ink.

[0019] Furthermore, in the above technical solution, in step S1, the temperature of the ring-opening polymerization reaction is 80℃-120℃, the reaction time is 6-12 hours, the catalyst is p-toluenesulfonic acid, the enzymatic hydrolyzed lignin and the polyetheramine are vacuum dried and dehydrated before the reaction, and after the reaction is completed, they are purified by dialysis bags and freeze-dried.

[0020] In practice, vacuum drying removes free moisture from the raw materials, preventing interference with the ring-opening polymerization reaction and ensuring the smooth grafting of polyetheramine segments onto the active sites of enzymatically hydrolyzed lignin. Matching the reaction temperature of 80℃-120℃ with a reaction time of 6-12 hours ensures the ring-opening polymerization reaction proceeds fully while avoiding uncontrolled branching of the polymer due to excessively high temperatures or long reaction times. Toluenesulfonic acid, as an acidic catalyst, efficiently catalyzes the ring-opening polymerization reaction, reducing the activation energy. Dialysis purification and freeze-drying remove unreacted monomers and small molecule impurities from the system, obtaining a high-purity hyperbranched polymer dispersant and avoiding the negative impact of impurities on the stability of the subsequent dye dispersion system.

[0021] Furthermore, in the above technical solution, in step S4, the hydroxyl-terminated silane coupling agent is added by dripping for 30-60 minutes. The hydroxyl-terminated silane coupling agent is pre-hydrolyzed with deionized water before dripping. The slurry temperature during the deep grinding process is controlled below 30°C. The crosslinking reaction is carried out continuously in the shear field of the sand mill.

[0022] In practice, pre-hydrolysis treatment before dripping allows the silane coupling agent to generate active silanol groups in advance, ensuring that it can quickly anchor on the surface of dye particles and undergo cross-linking reaction after being dripped into the slurry; uniform dripping over 30-60 minutes can avoid self-agglomeration and cross-linking caused by excessively high local concentration of silane coupling agent, ensuring that it is uniformly coated on the surface of dye particles; controlling the slurry temperature below 30℃ can inhibit the excessively rapid hydrolysis and condensation of silane coupling agent, avoiding excessive growth of cross-linking network leading to particle size exceeding the standard; the continuous shearing action of the sand mill shear field can make the silane coupling agent form a uniform and dense cross-linking network on the surface of dye particles, while avoiding secondary agglomeration of dye particles during the coating process.

[0023] Furthermore, in the above technical solution, in step S3, the grinding medium in the sand mill is zirconia microspheres, the diameter of the zirconia microspheres is 0.1-0.3 mm, and the deep grinding time is 2-5 hours; in step S5, the filtration and degassing is performed by pressure filtration using a polyethersulfone filter membrane with a pore size of 0.5 micrometers, and the operating pressure of the pressure filtration is 0.2-0.4 MPa.

[0024] In practice, 0.1-0.3 mm zirconia microspheres have high grinding efficiency, which can pulverize dye particles to the target nanoscale particle size within 2-5 hours, while avoiding the problems of insufficient grinding efficiency and excessively wide particle size distribution caused by excessively large grinding media diameter; 0.5 micron polyethersulfone filter membrane can effectively remove large particle agglomerates and impurities in the paste, ensuring that the ink passes smoothly through the nozzle of the inkjet printer; the 0.2-0.4 MPa pressure can ensure filtration efficiency while avoiding excessive pressure that could damage the filter membrane, thus ensuring the stability of ink quality.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention employs an enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant in combination with a terminal hydroxyl silane coupling agent to construct a siloxane crosslinking network and a hyperbranched polymer cavity coating layer on the exterior of the disperse dye powder. The three-dimensional topological structure of the hyperbranched polymer is fixed to the outside of the crosslinking network via hydrogen bonds, changing the fixation method of conventional linear dispersants which relies on physical adsorption. This composite coating structure allows the dye ink to maintain a dispersed particle state under the high-frequency shearing environment of the nozzle, eliminating nozzle clogging caused by secondary aggregation, avoiding the obstruction of free dispersant to the diffusion of dye into the polyester fiber, and allowing unfixed dye to be normally removed during the washing stage, thereby improving the wash fastness of printed fabrics.

[0026] 2. This invention regulates the surface tension of the ink system to a specific range by limiting the ring-opening polymerization conditions of enzymatically hydrolyzed lignin and polyetheramine, as well as the degree of branching of the hyperbranched polymer, combined with a mixed humectant composed of diethylene glycol and pyrrolidone, thus enabling the ink to meet the physical requirements of inkjet printing. Deep grinding of zirconium oxide microspheres of a specific diameter, combined with in-situ crosslinking of a terminal hydroxyl silane coupling agent in the grinding shear field, controls the thickness of the crosslinked network and coating layer, thereby improving the ink's anti-settling performance during storage. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments. Those skilled in the art can reproduce the technical solution of the present invention and achieve its claimed technical effects based on the content disclosed in this specification. It should be noted that the following embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention. Any non-substantial improvements and adjustments made based on the core concept of the present invention should fall within the scope of protection of the present invention.

[0028] All raw materials used in the embodiments of this invention are commercially available industrial-grade products. Among them: enzymatically hydrolyzed lignin was purchased from Shandong Longli Biotechnology Co., Ltd.; polyetheramines D230, D400, and D2000 were purchased from Huntsman Chemical; γ-glycidyl etheroxypropyltrimethoxysilane (KH560) and bis-(γ-triethoxysilylpropyl)tetrasulfide (Si69) were purchased from Nanjing Nengde Chemical; Disperse Blue 73 and Disperse Red 356 are both β-crystal single-component disperse dyes purchased from Zhejiang Runtu Co., Ltd.; naphthalenesulfonic acid formaldehyde condensate (NNO) was purchased from Jiangsu Wanqi Biotechnology; diethylene glycol, 2-pyrrolidone, p-toluenesulfonic acid, and isothiazolinone bactericides were all commercially available analytical grade reagents; and deionized water was laboratory-prepared secondary reverse osmosis water.

[0029] Example 1: Formulation composition (total mass 1000g): By mass percentage, the components are: disperse dye raw powder (Disperse Blue 73, β crystal form, initial average particle size 100nm) 10%; enzymatic hydrolysis lignin-based hyperbranched polymer dispersant 5%; terminal hydroxyl silane coupling agent (KH560 hydrolysis modified product) 2%; humectant 15% (diethylene glycol to 2-pyrrolidone mass ratio 2:1); isothiazolinone bactericide 0.3%; deionized water 67.7%.

[0030] The preparation parameters for the enzymatic hydrolyzed lignin-based hyperbranched polymer dispersant are as follows: enzymatic hydrolyzed lignin with a molecular weight of 2000 Daltons, polyetheramine D1000 with a molecular weight of 1000 Daltons, enzymatic hydrolyzed lignin to polyetheramine mass ratio of 1:3, and product branching degree of 0.45.

[0031] Preparation method: Step S1: Synthesis of enzymatic hydrolysis lignin-based hyperbranched polymer dispersant Enzymatically hydrolyzed lignin and polyetheramine D1000 were separately dehydrated in a vacuum drying oven at 60℃ for 12 hours. 100g of enzymatically hydrolyzed lignin and 300g of polyetheramine D1000 were weighed at a mass ratio of 1:3 and added to a four-necked reaction flask equipped with nitrogen protection and a reflux condenser. 500mL of 1,4-dioxane was added as a solvent, and the mixture was stirred until homogeneous. 4g of p-toluenesulfonic acid catalyst was then added, and nitrogen was purged into the system three times to replace the air. The temperature was raised to 100℃ and maintained at this temperature with stirring for 8 hours. After the reaction was complete, the reaction solution was cooled to room temperature and dialyzed using a dialysis bag with a molecular weight cutoff of 3500 Daltons for 72 hours, with deionized water replaced every 12 hours. After dialysis, the solution was dried in a freeze dryer at -50℃ for 24 hours to obtain an enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant.

[0032] Step S2: Pre-dispersion Weigh 50g of the synthesized hyperbranched polymer dispersant and 100g of Disperse Blue 73 raw powder according to the formula, add them to 500g of deionized water, and disperse them in a high-speed disperser at 3000rpm for 30min to obtain a uniform mixed slurry.

[0033] Step S3: Deep Grinding The mixed slurry was fed into a horizontal sand mill. The grinding media of the sand mill was 0.2mm zirconia microspheres with a filling rate of 80%. The linear speed of the sand mill was 12m / s. The temperature of the slurry was controlled not to exceed 25℃. The mill was ground for 3 hours.

[0034] Step S4: In-situ cross-linking coating When the deep grinding reached 1 hour, the pre-hydrolyzed hydroxyl-terminated silane coupling agent was added dropwise at a uniform rate for a total dropping time of 45 minutes. During the dropping process, the grinding process was maintained in the sand mill, and the slurry temperature was controlled to not exceed 25°C. After the dropping was completed, grinding continued for a total grinding time of 3 hours to allow the silane coupling agent to complete the in-situ cross-linking reaction on the surface of the dye particles, forming a siloxane cross-linking network. The pre-hydrolysis method of the hydroxyl-terminated silane coupling agent was as follows: 20g of KH560 was mixed with 40g of deionized water and 140g of anhydrous ethanol, the pH was adjusted to 4.5 with glacial acetic acid, and the mixture was stirred at room temperature for 30 minutes to obtain the pre-hydrolyzed product.

[0035] Step S5: Post-processing The ground slurry was transferred to a mixing tank, and 150g of humectant and 3g of bactericide were added according to the formula. Deionized water was added to bring the total mass to 1000g. The mixture was stirred at 1500rpm for 20 minutes to mix evenly. Then, a polyethersulfone filter membrane with a pore size of 0.5μm was used for pressure filtration at an operating pressure of 0.3MPa. After the filtrate was degassed under vacuum for 15 minutes, a high wash-resistance, sun-resistant inkjet printing disperse dye was obtained.

[0036] According to the test results, the disperse dye obtained in this embodiment has a siloxane crosslinking network thickness of 12 nm, a hyperbranched polymer coating layer thickness of 30 nm, and a surface tension of 35 mN / m at 25°C.

[0037] Example 2: Except for adjusting the mass percentage of disperse dye powder to 5% and the mass percentage of deionized water to 72.7%, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0038] Example 3: Except for adjusting the mass percentage of disperse dye powder to 15% and the mass percentage of deionized water to 62.7%, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0039] Example 4: Except for adjusting the mass percentage of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant to 2% and the mass percentage of deionized water to 70.7%, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0040] Example 5: Except for adjusting the mass percentage of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant to 8% and the mass percentage of deionized water to 64.7%, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0041] Example 6: Except for replacing the terminal hydroxyl silane coupling agent with an equal mass of bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si69) prehydrolysis product, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0042] Example 7: Except for adjusting the mass ratio of diethylene glycol to 2-pyrrolidone in the humectant to 3:1, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0043] Example 8: Except for adjusting the mass ratio of diethylene glycol to 2-pyrrolidone in the humectant to 1:1, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0044] Example 9: Except for replacing the disperse dye powder with an equal mass of Disperse Red 356 (β crystal form, heterocyclic structure, initial average particle size 100 nm), the rest of the formulation and preparation process are exactly the same as in Example 1.

[0045] Example 10: Except for adjusting the temperature of the ring-opening polymerization reaction in step S1 to 80°C and the reaction time to 12h, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0046] Example 11: Except for adjusting the dropping time of the terminal hydroxyl silane coupling agent in step S4 to 30 min and controlling the slurry temperature below 30°C during deep grinding, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0047] Example 12: Except for adjusting the diameter of the zirconia microspheres to 0.1 mm and the deep grinding time to 5 h in step S3, and adjusting the pressure of the pressure filtration operation to 0.4 MPa in step S5, the rest of the formulation and preparation process are exactly the same as in Example 1.

[0048] Comparative Example 1: Except for removing the enzymatic hydrolyzed lignin-based hyperbranched polymer dispersant from the formula and replenishing it with an equal mass of deionized water, the rest of the formula composition and preparation process are exactly the same as in Example 1.

[0049] Comparative Example 2: Using the conventional formula and preparation process described in the background art, specifically: Formula composition (total mass 1000g): 10% Dispersible Blue 73 raw powder, 5% Naphthalenesulfonic acid formaldehyde condensate (NNO) linear dispersant, 15% humectant (diethylene glycol and 2-pyrrolidone mass ratio 2:1), 0.3% isothiazolinone bactericide, 69.7% deionized water; no terminal hydroxyl silane coupling agent or enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant added.

[0050] Preparation process: Disperse Blue 73 raw powder and NNO dispersant were added to deionized water for pre-dispersing for 30 min, and then put into a horizontal sand mill for deep grinding for 4 h. After grinding, humectant and bactericide were added and mixed evenly. After pressure filtration through a 0.5 μm polyethersulfone filter membrane and vacuum degassing, the contrast disperse dye was obtained.

[0051] Comparative Example 3: Except for adjusting the dropping time of the terminal hydroxyl silane coupling agent in step S4 to 10 min (exceeding the 30-60 min range defined in the claims), the rest of the formulation and preparation process are exactly the same as in Example 1.

[0052] Comparative Example 4: Except for omitting the in-situ dropwise crosslinking step S4 and replacing it with deep grinding for 3 hours, the pre-hydrolyzed product of the terminal hydroxyl silane coupling agent was added to the ground slurry and stirred at room temperature for 30 minutes to carry out the crosslinking reaction, the rest of the formulation and preparation process were exactly the same as in Example 1.

[0053] Test method: Average particle size test: The initial average particle size and the average particle size after high-frequency shearing of the samples were tested using a Malvern Zetasizer Nano ZS90 dynamic light scattering instrument. The test temperature was 25℃, and each sample was tested in parallel 3 times, and the average value was taken.

[0054] High-frequency shear performance test: A high-speed shear emulsifier was used to shear the sample at 10,000 rpm for 1 hour to simulate the high-frequency shear environment of inkjet printing nozzles. The particle size change rate was calculated as follows: Particle size change rate = (average particle size after shearing - initial average particle size) / initial average particle size × 100%.

[0055] Thermal storage stability test: The sample was sealed and placed in a 50℃ constant temperature incubator for 7 days. The initial solid content of the sample and the solid content of the supernatant after thermal storage were tested, and the sedimentation rate was calculated: Sedimentation rate = (initial solid content - solid content of supernatant after thermal storage) / initial solid content × 100%.

[0056] Nozzle clogging rate test: A piezoelectric inkjet printer (20μm nozzle diameter, 1280 total nozzles) was used for continuous printing for 72 hours. The number of nozzles that were clogged and unable to dispense ink was counted, and the clogging rate was calculated as follows: Clogging rate = Number of clogged nozzles / Total number of nozzles × 100%.

[0057] Wash fastness test: The test was conducted in accordance with GB / T3921-2008 "Textiles - Tests for color fastness to soaping". A 5-level gray scale was used for rating, with the higher the level, the better the wash fastness.

[0058] Light fastness test: The test was conducted in accordance with GB / T8427-2019 "Textiles - Tests for color fastness to artificial light: Xenon arc". The blue wool standard sample was rated with an 8-level rating. The higher the level, the better the light fastness.

[0059] Surface tension test: The surface tension of the sample at 25℃ was tested using a fully automatic surface tension meter in accordance with the GB / T5549-2010 standard.

[0060] Test results: Table 1 Performance test results of each embodiment and comparative example Results analysis: The initial average particle size of Examples 1 to 12 was controlled within the nanometer range of 110-140 nm, and the particle size change rate after high-frequency shearing was less than 8%, which was far superior to the comparative examples. Among them, the particle size change rate of the best Example 1 was only 3.27%, which proved that the bilayer structure of "siloxane crosslinking network + hyperbranched polymer cavity coating" constructed in this invention achieved a stable combination between the coating layer and the dye particles through chemical bonding and hydrogen bonding, and completely solved the technical defects of easy desorption of linear dispersants and secondary agglomeration of dye particles under high-frequency shearing in the prior art.

[0061] The sedimentation rate of the ink after 7 days of heat storage at 50°C in Examples 1 to 12 was less than 3%, with no obvious stratification or precipitation. This proves that the hyperbranched polymer three-dimensional topology of the present invention can provide a strong steric hindrance effect, effectively inhibiting the sedimentation and aggregation of dye particles during long-term storage and improving the shelf-life stability of the ink.

[0062] The surface tension of Examples 1 to 12 was stable within the inkjet adaptation range of 30-40 mN / m, and the nozzle clogging rate was less than 1% after 72 hours of continuous printing. Example 1 achieved zero clogging, which fully meets the continuous production requirements of industrial inkjet printing.

[0063] Examples 1 to 12 all achieved a washing fastness of grade 4 or higher and a lightfastness of grade 5-6, far exceeding industry standards. The core reason for this is that the coating structure of this invention does not migrate to the polyester fiber surface during the high-temperature steam fixation stage, completely eliminating the obstruction of dye diffusion into the fiber by the free dispersant. This allows unfixed dye to detach normally during the washing stage, significantly improving washing fastness. Simultaneously, the siloxane crosslinking network isolates the dye molecules from UV radiation and moisture, greatly enhancing lightfastness.

[0064] Furthermore, by adjusting the proportion of core components and replacing functional excipients in Examples 2 to 9, and by adjusting the key parameters of the preparation process in Examples 10 to 12, all performance characteristics remained at an excellent level, demonstrating that the formulation system and preparation method of the present invention have strong robustness and universality, and fully cover the scope of protection defined by the claims.

[0065] Comparative Example 1 removed the core component, enzymatic hydrolysis of lignin-based hyperbranched polymer dispersant. Relying solely on the siloxane crosslinking network could not provide sufficient steric hindrance, resulting in a significant increase in the initial particle size of the dye particles. After high-frequency shearing, severe agglomeration occurred, with a particle size change rate exceeding 120%. The thermal storage sedimentation rate and nozzle clogging rate both increased significantly, and the color fastness decreased significantly. This directly proves that the hyperbranched polymer dispersant is the core necessary component for achieving the technical effects of this invention.

[0066] Comparative Example 2 uses the conventional linear dispersant and traditional preparation process described in the background art, but does not employ the double-layer coating structure of the present invention. The linear dispersant only binds to the surface of the dye particles through physical adsorption, and is easily desorbed under high-frequency shearing, resulting in secondary agglomeration of the dye particles. The nozzle clogging rate and thermal storage sedimentation rate are significantly deteriorated. At the same time, the desorbed free dispersant hinders the diffusion of dye into the fiber interior, resulting in a wash fastness of only grade 3 and a light fastness of less than grade 4. This is in stark contrast to the embodiments of the present invention, directly proving that the present invention solves the long-standing technical pain points of the prior art and achieves significant technical progress.

[0067] Comparative Example 3 shortened the dropping time of the hydroxyl-terminated silane coupling agent to 10 min, which exceeded the range defined in the claims. This resulted in an excessively high local concentration of the silane coupling agent in the slurry, causing it to agglomerate and crosslink. As a result, it was unable to form a uniform and dense siloxane crosslinking network on the surface of the dye particles, leading to a significant decrease in the coating effect and a significant deterioration in various performance indicators. This demonstrates that the process parameter range defined in this invention is a necessary condition for achieving stable coating.

[0068] Comparative Example 4 omits the crucial in-situ crosslinking step during the grinding process, instead adding the silane coupling agent after grinding. This prevents the use of the shear field of the sand mill to achieve uniform anchoring and crosslinking of the silane coupling agent on the surface of the nano-dye particles, resulting in uneven coating layers, weak bonding, and susceptibility to breakage and desorption under high-frequency shear. All performance characteristics are significantly inferior to Example 1, directly demonstrating that the in-situ crosslinking process of this invention is the core key step in constructing a stable double-layer coating structure.

[0069] In summary, this invention constructs a stable double-layer coating structure through the synergistic effect of enzymatic hydrolysis of lignin-based hyperbranched polymer dispersants and terminal hydroxyl silane coupling agents. This completely solves the technical defects of existing technologies, such as easy desorption of dispersants, easy aggregation of dyes, easy clogging of nozzles, and deterioration of color fastness. All embodiments have achieved stable and excellent technical effects, while comparative examples that violate the technical solution of this invention have shown significant performance degradation. This fully demonstrates that the technical solution of this invention is non-obvious and has achieved technical effects that are unexpected by those skilled in the art. It possesses outstanding substantive features and significant progress.

Claims

1. A high wash-resistance, lightfast inkjet printing disperse dye, wherein the disperse dye comprises the following components by weight percentage: Disperse dye raw materials 5%-15%; Enzymatic hydrolysis of lignin-based hyperbranched polymer dispersants 2%-8%; Hydroxyl-terminated silane coupling agents: 0.5%-3%; Moisturizer 10%-20%; Fungicide 0.1%-0.5%; Deionized water: 53.5%-82.4%; The enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant is a hyperbranched polymer with a three-dimensional topological structure synthesized by grafting polyetheramine segments onto enzymatically hydrolyzed lignin through a ring-opening polymerization reaction. The hydroxyl-terminated silane coupling agent coats the surface of the disperse dye powder and forms a siloxane crosslinking network, while the cavity structure of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant coats the outside of the siloxane crosslinking network.

2. The high washability and sun-resistant disperse dye for inkjet printing according to claim 1, characterized in that, The enzymatically hydrolyzed lignin has a molecular weight of 1000-3000 Daltons, the polyetheramine has a molecular weight of 400-2000 Daltons, the mass ratio of the enzymatically hydrolyzed lignin to the polyetheramine is 1:2 to 1:5, and the degree of branching of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant is 0.3-0.

6.

3. The high washability and sun-resistant disperse dye for inkjet printing according to claim 1, characterized in that, The hydroxyl-terminated silane coupling agent is selected from the product of hydrolysis modification of γ-glycidoxypropyltrimethoxysilane, or from bis-(γ-triethoxysilylpropyl)-tetrasulfide, and the molecular structure of the hydroxyl-terminated silane coupling agent contains at least two silanol groups.

4. The high washability and sun-resistant disperse dye for inkjet printing according to claim 1, characterized in that, The disperse dye powder is a single-component anthraquinone disperse dye or a single-component heterocyclic disperse dye. The average particle size of the disperse dye powder before coating is 50-150 nanometers, and the crystal morphology of the disperse dye powder is β crystal.

5. The high washability and sun-resistant disperse dye for inkjet printing according to claim 1, characterized in that, The humectant is a mixture of diethylene glycol and 2-pyrrolidone in a mass ratio of 3:1 to 1:

1. The humectant forms a homogeneous solution system with the deionized water. The amount of humectant added is used to adjust the surface tension of the disperse dye at 25°C to 30-40 mN / m.

6. The high washability and sun-resistant disperse dye for inkjet printing according to claim 1, characterized in that, The thickness of the siloxane crosslinking network is 5-20 nanometers, and the thickness of the coating layer of the enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant outside the siloxane crosslinking network is 10-50 nanometers. The coating layer and the siloxane crosslinking network are interconnected by hydrogen bonds.

7. A method for preparing a high wash-resistance, lightfast inkjet printing disperse dye, used to prepare the disperse dye according to any one of claims 1 to 6, the preparation method comprising the following steps: Step S1: Enzymatically hydrolyzed lignin and polyetheramine undergo ring-opening polymerization in the presence of a catalyst to synthesize an enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant. Step S2: The enzymatically hydrolyzed lignin-based hyperbranched polymer dispersant and disperse dye powder are added to deionized water for pre-dispersion to obtain a mixed slurry; Step S3: The mixed slurry is fed into a sand mill for deep grinding; Step S4: During the deep grinding process, a terminal hydroxyl silane coupling agent is added dropwise to cause the terminal hydroxyl silane coupling agent to undergo a cross-linking reaction on the surface of the dye particles. Step S5: Mix the ground slurry with a humectant and a bactericide until homogeneous, and then filter and degas to obtain the high washability and sun-resistant inkjet printing disperse dye.

8. The method for preparing a high wash-resistance, lightfast inkjet printing disperse dye according to claim 7, characterized in that, In step S1, the ring-opening polymerization reaction is carried out at a temperature of 80℃-120℃ for 6-12 hours. The catalyst is p-toluenesulfonic acid. The enzymatically hydrolyzed lignin and the polyetheramine are vacuum dried and dehydrated before the reaction. After the reaction is completed, they are purified by dialysis and freeze-dried.

9. The method for preparing a high wash-resistance, lightfast inkjet printing disperse dye according to claim 7, characterized in that, In step S4, the hydroxyl-terminated silane coupling agent is added dropwise over a period of 30-60 minutes. The hydroxyl-terminated silane coupling agent is pre-hydrolyzed with deionized water before being added. The slurry temperature during the deep grinding process is controlled below 30°C. The crosslinking reaction is carried out continuously in the shear field of the sand mill.

10. The method for preparing a high wash-resistance, lightfast inkjet printing disperse dye according to claim 7, characterized in that, In step S3, the grinding media in the sand mill is zirconia microspheres, the diameter of the zirconia microspheres is 0.1-0.3 mm, and the deep grinding time is 2-5 hours. In step S5, the filtration and degassing are performed using a polyethersulfone filter membrane with a pore size of 0.5 micrometers for pressure filtration, and the operating pressure of the pressure filtration is 0.2-0.4 MPa.

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