Dispersive wet sizing digital printing paste composition for Single Pass digital printing machine and preparation method thereof

Abstract

The invention discloses a disperse wet sizing digital printing paste composition for a Single Pass digital printing machine. The disperse wet sizing digital printing paste composition comprises hydroxyethyl starch, a dispersing agent, a gellan gum thickening agent, an ethyl hydroxyethyl cellulose thickening agent, a humectant, a pH regulator, a defoaming agent and a preservative. A preparation method of a disperse wet sizing digital printing paste composition for a Single Pass digital printing machine comprises the following steps: sequentially adding hydroxyethyl starch, a dispersing agent, a gellan gum thickening agent, an ethyl hydroxyethyl cellulose thickening agent, a humectant, a pH regulator, a defoaming agent and a preservative into a stirring kettle, and uniformly stirring under the stirring condition at the speed of 350-550r / min to obtain the disperse wet sizing digital printing paste composition for the Single Pass digital printing machine. The stirring time is 40-50 minutes, so as to obtain the final digital printing paste composition. The sizing agent has excellent ink locking capacity, efficient sizing effect and strong fabric adhesive force, has remarkable advantages in the aspects of color yield and definition, can effectively improve the digital printing quality, and meets the requirements of the textile printing and dyeing industry for sizing of high-quality digital printing fabric.

Description

Technical Field

[0001] The present invention relates to digital printing technology in the field of textile printing and dyeing, and specifically relates to a disperse wet sizing digital printing paste composition for a Single Pass digital printing machine and a preparation method thereof. Background Art

[0002] In the current booming situation of the textile printing and dyeing industry, the Single Pass digital printing machine has gradually become the mainstream printing equipment in the industry with its high production efficiency and high-precision printing results. However, when traditional printing pastes are adapted to the Single Pass digital printing machine, there are many technical bottlenecks to be solved. From the perspective of fabric color uniformity, traditional pastes are prone to cause the ink to migrate horizontally and vertically on the fabric surface after sizing the fabric, which directly leads to uneven color and low color yield of the printed finished product, seriously affecting the appearance quality and market competitiveness of the product. In the sizing link of digital printing, due to the poor thixotropic performance of traditional pastes, it is impossible to accurately control the transfer and spreading of the ink on the fabric surface, making the clarity and fineness of the printed pattern greatly reduced, and it is difficult to meet the current consumers' demand for high-quality printed products. Summary of the Invention

[0003] The present invention is to solve the technical problem of providing a high-performance disperse wet sizing digital printing paste technology that can fully adapt to the working characteristics of the Single Pass digital printing machine and has excellent ink locking ability, high-efficiency sizing effect and strong fabric adhesion.

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

[0005] A disperse wet sizing digital printing paste composition for a Single Pass digital printing machine, comprising:

[0006] Hydroxyethyl starch, the weight percentage of which accounts for 71.4%-86.7% of the composition;

[0007] Dispersant, the weight percentage of which accounts for 2-4% of the composition;

[0008] Gellan gum thickener, the weight percentage of which accounts for 3-8% of the composition;

[0009] Ethyl hydroxyethyl cellulose thickener, the weight percentage of which accounts for 5-10% of the composition;

[0010] Humectant, the weight percentage of which accounts for 3-6% of the composition;

[0011] pH regulator, the weight percentage of which accounts for 0.1-0.2% of the composition;

[0012] Defoamer, with a weight percentage of 0.1 - 0.2% of the composition;

[0013] Preservative, with a weight percentage of 0.1 - 0.2% of the composition.

[0014] The preparation method of the hydroxyethyl starch includes the following steps:

[0015] S1, alkalization reaction process: Using cassava starch as the basic raw material, dispersing it in an organic solvent ethanol solution, adding sodium hydroxide to form an alkaline suspension; turning on the stirring function, stirring at a constant speed of 50 - 100 r / min, and at the same time slowly heating the reaction system to 45°C by means of jacket heating, reacting for 1 hour to fully swell the starch granules and enhance the reaction activity;

[0016] S2, etherification reaction process: Increasing the stirring speed to 100 - 150 r / min and stirring at a constant speed, and at the same time slowly heating the reaction system to 50°C by means of jacket heating. After the temperature is stable, slowly introducing ethylene oxide in a constant-pressure dropping manner within the range of the molar ratio of ethylene oxide to starch of 0.1 - 0.3:1. During the reaction process, controlling the reaction temperature between 45 - 55°C and the pressure at 0.2 - 0.4 MPa, and the reaction time lasting for 4 - 6 hours to ensure the full progress of the etherification reaction;

[0017] S3, neutralization and washing process: After the etherification reaction is completed, slowly dropping an appropriate amount of hydrochloric acid solution into the reaction system to adjust the pH value of the system to 6 - 7 to terminate the reaction process. Subsequently, effectively separating the reaction product from the reaction solution through solid-liquid separation technologies such as centrifugal separation or vacuum filtration, and washing the obtained solid product with acetone to remove residual ethylene oxide, salts, and low-molecular by-products;

[0018] S4, drying and pulverization treatment: Feeding the washed product into a drying equipment for drying treatment. During spray drying, controlling the inlet air temperature at 180 - 220°C and the outlet air temperature at 80 - 100°C; during vacuum drying, controlling the drying temperature at 60 - 80°C and the vacuum degree at -0.08 to -0.1 MPa to reduce the moisture content of the product to below 10%. The dried product is pulverized by means of air flow pulverization or mechanical pulverization to make its particle size reach the required particle size distribution, and finally hydroxyethyl starch is obtained.

[0019] In the S4 step, the washed product is fed into a drying equipment for drying treatment, and spray drying or vacuum drying is selected for the drying treatment.

[0020] The dispersant is a polymer dispersant.

[0021] The polymer dispersant is a polyether-modified acrylate copolymer.

[0022] The humectant is sorbitol or propylene glycol.

[0023] The pH regulator is sodium dihydrogen phosphate or sodium citrate.

[0024] The defoamer is a polydimethylsiloxane defoamer.

[0025] The preservative is a Kathon preservative.

[0026] A preparation method of a disperse wet-sizing digital printing paste composition for a Single Pass digital printing machine is as follows: hydroxyethyl starch, a dispersant, a gellan gum thickener, an ethyl hydroxyethyl cellulose thickener, a humectant, a pH regulator, a defoamer, and a preservative are sequentially added to a stirring kettle and stirred evenly under the stirring condition at a speed of 350 - 550 revolutions per minute for 40 - 50 minutes to obtain the final digital printing paste composition, wherein the weight percentage of hydroxyethyl starch in the composition is 71.4% - 86.7%, the weight percentage of the dispersant in the composition is 2 - 4%, the weight percentage of the gellan gum thickener in the composition is 3 - 8%, the weight percentage of the ethyl hydroxyethyl cellulose thickener in the composition is 5 - 10%, the weight percentage of the humectant in the composition is 3 - 6%, the weight percentage of the pH regulator in the composition is 0.1 - 0.2%, the weight percentage of the defoamer in the composition is 0.1 - 0.2%; and the weight percentage of the preservative in the composition is 0.1 - 0.2%.

[0027] The technical effects that can be achieved by the present invention are as follows: A disperse wet-sizing digital printing paste composition for a Single Pass digital printing machine of the present invention includes hydroxyethyl starch, a dispersant, a gellan gum thickener, an ethyl hydroxyethyl cellulose thickener, a humectant, a pH regulator, a defoamer, and a preservative. Each component plays an indispensable synergistic role in the paste system, jointly ensuring the excellent performance of the paste, enabling the paste to have excellent ink-locking ability, efficient sizing effect, and strong fabric adhesion, having significant advantages in color yield and clarity, being able to effectively improve the quality of digital printing, and meeting the requirements of the textile printing and dyeing industry for sizing high-quality digital printing fabrics. Detailed Embodiments

[0028] The following further elaborates on the present invention in conjunction with...

[0029] A disperse wet-sizing digital printing paste composition for a Single Pass digital printing machine includes:

[0030] Hydroxyethyl starch, the weight percentage of which in the composition is 71.4% - 86.7%;

[0031] A dispersant, the weight percentage of which in the composition is 2 - 4%;

[0032] Gellan gum thickener, with a weight percentage of 3 - 8% of the composition;

[0033] Ethyl hydroxyethyl cellulose thickener, with a weight percentage of 5 - 10% of the composition;

[0034] Humectant, with a weight percentage of 3 - 6% of the composition;

[0035] pH regulator, with a weight percentage of 0.1 - 0.2% of the composition;

[0036] Defoamer, with a weight percentage of 0.1 - 0.2% of the composition;

[0037] Preservative, with a weight percentage of 0.1 - 0.2% of the composition.

[0038] The preparation method of hydroxyethyl starch therein includes the following steps:

[0039] S1, alkalization reaction process: Using cassava starch as the basic raw material, dispersing it in an organic solvent ethanol solution, adding sodium hydroxide to form an alkaline suspension; turning on the stirring function, stirring at a constant speed of 50 - 100 r / min, and at the same time slowly heating the reaction system to 45°C by means of jacket heating, reacting for 1 hour to fully swell the starch granules and enhance the reaction activity;

[0040] S2, etherification reaction process: Increasing the stirring speed to 100 - 150 r / min and stirring at a constant speed, and at the same time slowly heating the reaction system to 50°C by means of jacket heating. After the temperature is stable, slowly introducing ethylene oxide in a constant-pressure dropping manner according to the molar ratio of ethylene oxide to starch within the range of 0.1 - 0.3:1. During the reaction process, controlling the reaction temperature between 45 - 55°C, maintaining the pressure at 0.2 - 0.4 MPa, and the reaction time lasting for 4 - 6 hours to ensure the full progress of the etherification reaction;

[0041] S3, neutralization and washing process: After the etherification reaction is completed, slowly dropping an appropriate amount of hydrochloric acid solution into the reaction system to adjust the pH value of the system to 6 - 7 to terminate the reaction process. Subsequently, effectively separating the reaction product from the reaction solution through solid-liquid separation techniques such as centrifugal separation or vacuum filtration, and washing the obtained solid product with acetone to remove residual ethylene oxide, salts and low-molecular by-products;

[0042] S4, Drying and Grinding Process: Feed the washed product into a drying equipment for drying. During spray drying, control the inlet air temperature at 180 - 220°C and the outlet air temperature at 80 - 100°C; during vacuum drying, control the drying temperature at 60 - 80°C and the vacuum degree at -0.08 to -0.1 MPa to reduce the moisture content of the product to less than 10%. The dried product is ground by means of pneumatic grinding or mechanical grinding to achieve the required particle size distribution, and finally hydroxyethyl starch is obtained.

[0043] Specifically, in step S4, feed the washed product into a drying equipment for drying, and the drying process selects spray drying or vacuum drying.

[0044] The dispersant is a polymer dispersant.

[0045] The polymer dispersant is a polyether-modified acrylate copolymer.

[0046] The humectant is sorbitol or propylene glycol.

[0047] The pH regulator is sodium dihydrogen phosphate or sodium citrate.

[0048] The defoamer is a polydimethylsiloxane defoamer.

[0049] The preservative is a Kathon preservative.

[0050] A preparation method of a disperse wet sizing digital printing paste composition for a Single Pass digital printer. Add hydroxyethyl starch, dispersant, gellan gum thickener, ethyl hydroxyethyl cellulose thickener, humectant, pH regulator, defoamer and preservative into a stirring kettle in sequence, and stir evenly under the stirring condition of 350 - 550 revolutions per minute for 40 - 50 minutes to obtain the final digital printing paste composition, wherein the weight percentage of hydroxyethyl starch in the composition is 71.4% - 86.7%, the weight percentage of the dispersant in the composition is 2 - 4%, the weight percentage of the gellan gum thickener in the composition is 3 - 8%, the weight percentage of the ethyl hydroxyethyl cellulose thickener in the composition is 5 - 10%, the weight percentage of the humectant in the composition is 3 - 6%, the weight percentage of the pH regulator in the composition is 0.1 - 0.2%, the weight percentage of the defoamer in the composition is 0.1 - 0.2%; the weight percentage of the preservative in the composition is 0.1 - 0.2%.

[0051] Dispersant: A high molecular polymer dispersant with a special molecular structure design is used, such as a polyether-modified acrylate copolymer. The dispersant molecule chain contains both an anchoring group that is dye-philic and a hydrophilic polyether segment. It can form a firm adsorption layer on the surface of dye particles and, through the dual effects of steric hindrance and electrostatic repulsion, evenly and stably disperse the dye particles in the slurry system, effectively inhibiting the agglomeration and precipitation of dyes, and significantly improving the stability of the ink spreading on the fabric surface.

[0052] Thickener: Gellan gum and ethyl hydroxyethyl cellulose are selected for compounding as the thickener system. Gellan gum can form a high-strength gel network structure at low concentrations, endowing the slurry with good thixotropic properties, making it have a higher viscosity in the static state and improving the ink-locking ability of the slurry; ethyl hydroxyethyl cellulose, with its good film-forming property and water retention property, can enhance the adhesion between the slurry and the fabric and maintain the moisture content of the printed fabric during the printing process to ensure the uniform transfer of the ink. The two work synergistically to provide the slurry with more appropriate thixotropic properties, greatly improving the clarity and fineness of the printed pattern.

[0053] Humectant: Sorbitol or propylene glycol is used as the humectant. Sorbitol has extremely strong hygroscopicity and can absorb and retain the moisture in the environment during the printing process to prevent the slurry from drying out due to excessive evaporation of moisture; propylene glycol not only has good moisture retention performance but also can effectively reduce the surface tension of the slurry, improve the fluidity and permeability of the slurry, enabling the ink to penetrate deeper into the fabric fibers, thereby improving the quality and color fastness of the printing.

[0054] pH regulator: Sodium dihydrogen phosphate or sodium citrate is used as the pH regulator to accurately adjust the pH value of the slurry to between 6.5 and 7.5. Within this pH range, the chemical stability of the slurry system is the best, which can effectively inhibit the hydrolysis and color change reactions of dyes and ensure the full play of the synergistic effects among various components.

[0055] Defoamer: An organosilicon defoamer with an ultra-low surface tension is selected, such as a polydimethylsiloxane defoamer. This defoamer can quickly spread to the surface of the foam, reduce the surface tension of the foam film, cause it to break and disappear, thus effectively avoiding printing defects such as pores and color spots caused by the generation of foam during the preparation and printing of the slurry.

[0056] Preservative: A highly efficient and broad-spectrum isothiazolinone preservative is used, such as Kathon preservative. This preservative can react chemically with biological macromolecules such as proteins and enzymes in microbial cells to disrupt their normal physiological and metabolic functions, thereby effectively inhibiting the growth and reproduction of microorganisms such as bacteria, molds, and yeasts, extending the storage period of the slurry, and ensuring the quality stability of the slurry during storage and use.

[0057] The digital printing slurry composition obtained by the above-mentioned ratio and preparation method has the following advantages:

[0058] 1. Excellent ink locking ability: Through the synergistic effect of hydroxyethyl starch and high molecular polymer dispersant, a stable adsorption layer and steric barrier can be formed on the surface of dye particles, effectively inhibiting the agglomeration and precipitation of dyes, ensuring that the ink is evenly spread on the fabric surface during the digital printing process, thereby achieving uniform printing color.

[0059] 2. Excellent sizing effect: The thickener system of gellan gum and ethyl hydroxyethyl cellulose can provide the slurry with ideal thixotropic properties, so that it can accurately control the transfer and spreading of ink during the printing process, achieve accurate ink locking and stable sizing, significantly improve the clarity and fineness of the printed pattern, and meet the requirements of high-precision digital printing.

[0060] 3. Super strong adhesion: The hydroxyethyl starch prepared by the above method has good film-forming and adhesion properties, and the penetration of the moisturizer on the fabric fibers can enhance the bonding force between the slurry and the fabric, so that the printed pattern can still maintain good stability in harsh environments such as washing and friction, and is not easy to fade or fall off, which greatly improves the washing fastness and wear resistance of the printed products and extends the service life of the products.

[0061] 4. Good storage stability: The addition of isothiazolinone preservatives can effectively inhibit the growth and reproduction of microorganisms, prevent the slurry from mildew, corruption and other quality problems during storage, extend the storage period of the slurry, ensure the quality stability of the slurry during storage and use, and reduce production costs and resource waste.

[0062] 5. Environmental protection: The slurry composition of the present invention does not contain harmful substances, such as formaldehyde, heavy metals, etc., and complies with relevant national environmental protection standards and regulatory requirements. It will not cause pollution to the environment during production and use, and is conducive to promoting the sustainable development of the textile printing and dyeing industry.

[0063] Example 1

[0064] Slurry formula:

[0065] Hydroxyethyl starch: 86.7%

[0066] Polyether modified acrylate copolymer (dispersant): 2%

[0067] Gellan gum (thickener): 3%

[0068] Ethyl hydroxyethyl cellulose (thickener): 5%

[0069] Sorbitol (humectant): 3%

[0070] Sodium dihydrogen phosphate (pH regulator): 0.1%

[0071] Polydimethylsiloxane defoamer (defoamer): 0.1%

[0072] Kathon preservative (preservative): 0.1%

[0073] Preparation steps:

[0074] Add the hydroxyethyl starch, polyether-modified acrylate copolymer, gellan gum, ethyl hydroxyethyl cellulose, sorbitol, sodium dihydrogen phosphate, polydimethylsiloxane defoamer, and Kathon preservative in the above ratios to a stirring kettle in sequence, and stir evenly under the stirring condition of 350 revolutions per minute for 40 minutes to obtain the final digital printing paste composition.

[0075] Printing application:

[0076] Dilute the prepared digital printing paste composition with water at a ratio of 1:20 to make a paste, and then perform sizing treatment on the fabric. Use a Single Pass digital printer to perform digital printing on the sized polyester fabric.

[0077] Color evaluation: Use a Datacolor 650 colorimeter to measure the color of the printed fabric according to the CIELAB color space standard.

[0078] Clarity evaluation: Observe the printed pattern through a high-resolution microscope, and use image analysis software to quantitatively analyze the sharpness of the pattern edge and the integrity of the lines.

[0079] Test items Test data K / S value 12.5 ΔE*ab 1.8 Clarity Above 93%

[0080] The measurement results show that in this Example 1, the K / S value (color depth) of the fabric reaches 12.5, indicating a high color yield, good color vividness and saturation, the deviation ΔE*ab from the target color is less than 2.0, and the color accuracy is high; the clarity of the printed pattern reaches 93%, and the fine textures and lines in the pattern are clear and continuous, without phenomena such as blurring and broken lines, meeting the printing requirements of complex patterns.

[0081] Example 2

[0082] Slurry formula:

[0083] Hydroxyethyl starch: 80.6%

[0084] Polyether-modified acrylate copolymer (dispersant): 3%

[0085] Gellan gum (thickener): 5%

[0086] Ethyl hydroxyethyl cellulose (thickener): 7%

[0087] Propylene glycol (humectant): 4%

[0088] Sodium citrate (pH regulator): 0.14%

[0089] Polydimethylsiloxane defoamer (defoamer): 0.13%

[0090] Kathon preservative (preservative): 0.13%

[0091] Preparation steps:

[0092] Add the hydroxyethyl starch, polyether-modified acrylate copolymer, gellan gum, ethyl hydroxyethyl cellulose, propylene glycol, sodium citrate, polydimethylsiloxane defoamer, and Kathon preservative in the above ratios to the stirring kettle in sequence, and stir evenly under the stirring condition of 450 revolutions per minute for 45 minutes to obtain the final digital printing paste composition.

[0093] Printing application:

[0094] Dilute the prepared composition with water at a ratio of 1:20 to make a paste, and apply the pasted slurry to the fabric for sizing. Then, use a Single Pass digital printer to perform digital printing on the sized polyester fabric.

[0095] Color evaluation: Use a Datacolor 650 colorimeter to measure the color of the printed fabric according to the CIELAB color space standard.

[0096] Clarity evaluation: Observe the printed pattern through a high-resolution microscope, and use image analysis software to quantitatively analyze the sharpness of the pattern edge and the integrity of the lines.

[0097] Test items Test data K / S value 11.8 ΔE*ab 1.7 Clarity Above 95%

[0098] The measurement results show that in this Example 2, the K / S value (color depth) of the fabric reaches 11.8, indicating a high color yield, good color vividness and saturation, the deviation ΔE*ab from the target color is less than 2.0, and the color accuracy is high. The edge of the printed pattern is sharp, the line width is uniform, the clarity reaches more than 95%, the pattern details are clearly distinguishable, and it can meet the requirements of high-precision printing.

[0099] Example 3

[0100] Slurry formula:

[0101] Hydroxyethyl starch: 71.4%

[0102] Polyether-modified acrylate copolymer (dispersant): 4%

[0103] Gellan gum (thickener): 8%

[0104] Ethyl hydroxyethyl cellulose (thickener): 10%

[0105] Sorbitol (humectant): 6%

[0106] Sodium citrate (pH regulator): 0.2%

[0107] Polydimethylsiloxane defoamer (defoamer): 0.2%

[0108] Kathon preservative (preservative): 0.2%

[0109] Preparation steps:

[0110] Add the hydroxyethyl starch, polyether-modified acrylate copolymer, gellan gum, ethyl hydroxyethyl cellulose, sorbitol, sodium citrate, polydimethylsiloxane defoamer, and Kathon preservative in the above ratios into a stirring kettle in sequence, and stir evenly under the stirring condition of 550 revolutions per minute for 50 minutes to obtain the final digital printing paste composition.

[0111] Printing application:

[0112] Slurry the prepared composition with water in a ratio of 1:20, perform sizing treatment on the fabric after forming a paste, and perform digital printing on the sized polyester fabric with a Single Pass digital printer.

[0113] Color evaluation: Use a Datacolor 650 colorimeter to measure the color of the printed fabric according to the CIELAB color space standard.

[0114] Clarity evaluation: Observe the printed pattern through a high-resolution microscope, and quantitatively analyze the sharpness of the pattern edge and the integrity of the lines using image analysis software.

[0115] Test items Test data K / S value 11.5 ΔE*ab 1.5 Clarity Above 98%

[0116] The measurement results show that in this Example 3, the K / S value (color depth) of the fabric reaches 11.5, indicating a high color yield, good color vividness and saturation, the deviation ΔE*ab from the target color is less than 2.0, reaching 1.5, with higher color accuracy. The printed pattern has strong layering and three-dimensional sense, the clarity reaches more than 98%, and the pattern details are close to the original physical DPI of the nozzle, which can meet the requirements of ultra-fine line printing.

[0117] Comparative example:

[0118] Using a printing paste with traditional sodium alginate as the main body, it is prepared by conventional methods and used for printing polyester fabrics on a Single Pass digital printer.

[0119] Color evaluation: Measured using the same Datacolor 650 colorimeter, the K / S value of the fabric is only 8.0, the color is significantly lighter, the deviation ΔE*ab from the target color is greater than 5.0, the color accuracy is poor, and there is an obvious color difference.

[0120] Clarity evaluation: Observed through a microscope, the edges of the printed pattern are blurred, the lines are uneven in thickness and broken. Evaluated using image analysis software, the clarity is only 70%, and the pattern details are severely lost, unable to meet the requirements of high-quality printing.

[0121] Conclusion: Through the comparison of the examples and comparative examples, it can be clearly seen that the disperse wet sizing digital printing paste composition of the present invention for Single Pass digital printers has significant advantages in terms of color development and clarity, can effectively improve the printing quality, and meet the needs of the textile printing and dyeing industry for high-quality printing pastes.

Claims

1. A disperse wet sizing digital printing paste composition for a Single Pass digital printing machine, characterized in that, Comprising: Hydroxyethyl starch, which accounts for 71.4% - 86.7% by weight of the composition; Dispersant, which accounts for 2 - 4% by weight of the composition; Gellan gum thickener, which accounts for 3 - 8% by weight of the composition; Ethyl hydroxyethyl cellulose thickener, which accounts for 5 - 10% by weight of the composition; Humectant, which accounts for 3 - 6% by weight of the composition; pH regulator, which accounts for 0.1 - 0.2% by weight of the composition; Defoamer, which accounts for 0.1 - 0.2% by weight of the composition; Preservative, which accounts for 0.1 - 0.2% by weight of the composition.

2. The disperse wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that, The preparation method of the hydroxyethyl starch comprises the following steps: S1, alkalization reaction process: Using cassava starch as the basic raw material, dispersing it in an organic solvent ethanol solution, adding sodium hydroxide to form an alkaline suspension; turning on the stirring function, stirring at a constant speed of 50 - 100 r / min, and at the same time slowly heating the reaction system to 45°C by means of jacket heating, reacting for 1 hour to fully swell the starch granules and enhance the reaction activity; S2, etherification reaction process: Increasing the stirring speed to 100 - 150 r / min for uniform stirring, and at the same time slowly heating the reaction system to 50°C by means of jacket heating. After the temperature is stable, slowly introducing ethylene oxide in a constant-pressure dropping manner within the range of the molar ratio of ethylene oxide to starch of 0.1 - 0.3:

1. During the reaction process, controlling the reaction temperature between 45 - 55°C, maintaining the pressure at 0.2 - 0.4 MPa, and the reaction time lasting for 4 - 6 hours to ensure the full progress of the etherification reaction; S3, neutralization and washing process: After the etherification reaction is completed, slowly dropping an appropriate amount of hydrochloric acid solution into the reaction system to adjust the pH value of the system to 6 - 7 to terminate the reaction process. Subsequently, effectively separating the reaction product from the reaction solution through solid-liquid separation technologies such as centrifugal separation or vacuum filtration, and washing the obtained solid product with acetone to remove residual ethylene oxide, salts, and low-molecular by-products; S4, drying and pulverization treatment: Feeding the washed product into a drying device for drying treatment. During spray drying, controlling the inlet air temperature at 180 - 220°C and the outlet air temperature at 80 - 100°C; during vacuum drying, controlling the drying temperature at 60 - 80°C and the vacuum degree at -0.08 to -0.1 MPa to reduce the moisture content of the product to less than 10%. The dried product is pulverized by means of air flow pulverization or mechanical pulverization to make its particle size reach the required particle size distribution, and finally hydroxyethyl starch is obtained.

3. The disperse wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 2, wherein: In the step S4, the washed product is fed into a drying device for drying treatment, and spray drying or vacuum drying is selected for the drying treatment.

4. The disperse wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The dispersant is a polymer dispersant.

5. A disperse wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 4, characterized in that: The polymer dispersant is a polyether-modified acrylate copolymer.

6. The disperse wet-sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The humectant is sorbitol or propylene glycol.

7. A disperse wet sizing digital printing paste composition for a Single Pass digital printer according to claim 1, characterized in that: The pH regulator is sodium dihydrogen phosphate or sodium citrate.

8. The disperse wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The defoamer is a polydimethylsiloxane defoamer.

9. A disperse wet sizing digital printing paste composition for a Single Pass digital printing machine according to claim 1, characterized in that: The preservative is a Kathon preservative.

10. A method for preparing a disperse wet sizing digital printing paste composition for a Single Pass digital printing machine, characterized in that: Hydroxyethyl starch, a dispersant, gellan gum thickener, ethyl hydroxyethyl cellulose thickener, humectant, pH regulator, defoamer and preservative are added to a stirring kettle in sequence, and stirred evenly under the stirring condition at a speed of 350 - 550 revolutions per minute for 40 - 50 minutes to obtain the final digital printing paste composition, wherein the weight percentage of hydroxyethyl starch accounts for 71.4% - 86.7% of the composition, the weight percentage of the dispersant accounts for 2 - 4% of the composition, the weight percentage of the gellan gum thickener accounts for 3 - 8% of the composition, the weight percentage of the ethyl hydroxyethyl cellulose thickener accounts for 5 - 10% of the composition, the weight percentage of the humectant accounts for 3 - 6% of the composition, the weight percentage of the pH regulator accounts for 0.1 - 0.2% of the composition, the weight percentage of the defoamer accounts for 0.1 - 0.2% of the composition; the weight percentage of the preservative accounts for 0.1 - 0.2% of the composition.