Pigment yellow 74 self-dispersing color paste and preparation method thereof

Abstract

The invention relates to the technical field of pigment dispersion, in particular to pigment yellow 74 self-dispersing color paste and a preparation method thereof. The preparation method of the pigment yellow 74 self-dispersing color paste provided by the invention comprises the steps of hydrolysis of pigment yellow 155 and preparation of the pigment yellow 74 self-dispersing color paste. The pigment yellow 155 hydrolysate is mainly used as a dispersing agent and a crystallization inhibitor of the pigment yellow 74, the dispersity of the pigment yellow 74 is remarkably improved, the agglomeration phenomenon is reduced, the stability of the pigment yellow 74 self-dispersing color paste is improved, the coloring performance and the stability are superior to those of traditional grinding color paste, and the application range in an ink formula is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of pigment dispersion, in particular to a self-dispersing pigment yellow 74 color paste and a preparation method thereof. Background Art

[0002] Pigment Yellow 74 is an organic pigment widely used in coatings, inks, plastics and other fields, with excellent tinting strength and light resistance. However, Pigment Yellow 74 has the problem of poor dispersibility in actual application and is prone to agglomeration, resulting in relatively poor coloring effect and stability. To solve this problem, the traditional method is to use dispersants to improve the dispersibility of pigments, but these dispersants often have problems such as high cost and environmental unfriendliness, and the dispersion effect still needs to be improved. For example, it may cause larger particle size and less bright color. In addition, some dispersants use surfactants with low surface tension, which will make the surface tension of the color paste too low, thereby limiting its application range in ink formulations.

[0003] U.S. Patent No. 5,024,698A mainly discloses a method for modifying Pigment Yellow 74 by using an azomethine coupling component to improve its application performance in water-based inks and NC inks, such as reducing viscosity and improving gloss. This method achieves improved pigment performance by introducing an azomethine coupling agent during the pigment synthesis process. However, this method requires a diazo coupling reaction at low temperatures, which has a complex process flow and high requirements for production equipment and production licenses, making it unfavorable for actual industrial production applications. At the same time, the process also produces a large amount of wastewater, increasing the burden of environmental protection treatment. Similarly, U.S. Patent No. 20040163569 discloses a method of using p-aminobenzenesulfonic acid or p-aminobenzoic acid to replace part of p-nitroaniline o-methyl ether, and preparing a water-soluble modified pigment through a diazo reaction coupling scheme, and using it as a dispersant to prepare a self-dispersing color paste. However, the modifications involved in the above methods need to be carried out during the synthesis of Pigment Yellow 74, which requires a low-temperature diazo coupling reaction. The process is complex and the process flow is long. It exceeds the equipment and production license requirements of ink manufacturers, is not conducive to actual production applications, and will generate a large amount of wastewater, which is not conducive to environmental protection.

[0004] Therefore, there is an urgent need to develop an efficient, environmentally friendly, stable and high surface tension self-dispersible pigment yellow 74 paste, which is of great significance for promoting the application of pigment yellow 74 in coatings, inks, plastics and other fields. Summary of the Invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing a self-dispersible pigment yellow 74 paste, comprising:

[0006] S1. Hydrolysis of Pigment Yellow 155: Mix Pigment Yellow 155 and an alkaline aqueous solution, stir and react for 1-3 hours to obtain a Pigment Yellow 155 hydrolyzate solution, then filter out unreacted Pigment Yellow 155, adjust the pH of the reaction solution to 6-7, obtain a Pigment Yellow 155 hydrolyzate precipitate, wash with water, and dry to constant weight to obtain Pigment Yellow 155 hydrolyzate;

[0007] S2. Preparation of Pigment Yellow 74 Self-Dispersible Color Paste: Mix Pigment Yellow 74 and Pigment Yellow 155 hydrolyzate with a dispersant, add water and stir evenly, then disperse at high speed, grind, desalt, purify and concentrate to obtain Pigment Yellow 74 Self-Dispersible Color Paste.

[0008] As an practicable example, the reaction temperature in step S1 is 70-100°C.

[0009] As an implementable case, the alkaline aqueous solution includes a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution.

[0010] Furthermore, the molar concentration of the sodium hydroxide aqueous solution is 1-4 mol / L.

[0011] As an implementable case, the mass ratio of the hydrolyzate of Pigment Yellow 74 and Pigment Yellow 155 is 1:(0.1-0.15).

[0012] Pigment Yellow 74 itself has excellent tinting strength and lightfastness, but Pigment Yellow 74 has problems such as poor dispersibility and easy agglomeration, which affect its coloring effect and stability. Therefore, an effective dispersant is needed to improve its performance. Pigment Yellow 155 and Pigment Yellow 74 are different types of azo pigments. Pigment Yellow 74 is a monoazo pigment, while Pigment Yellow 155 is a disazo raw material. Their chemical structures have certain similarities and compatibility, so the hydrolyzate of Pigment Yellow 155 can interact well with Pigment Yellow 74. Through the hydrolysis reaction, Pigment Yellow 155 can produce a hydrolyzate with dispersibility. The hydrolyzate can adsorb on the surface of Pigment Yellow 74 particles, providing steric hindrance and electrostatic repulsion, thereby effectively improving the dispersibility of Pigment Yellow 74. Moreover, using Pigment Yellow 155 hydrolyzate as a dispersant has a relatively simple production process and can reduce production costs. At the same time, it avoids the problems that traditional dispersants may bring such as environmental unfriendliness and poor dispersion effect, and improves the overall performance of the color paste, giving it higher surface tension, better stability and tinting strength.

[0013] As an implementable case, the acid value of the dispersant is 180-210 mgKOH / g and the molecular weight is 8000-12000.

[0014] Furthermore, the dispersant has an acid value of 200 mgKOH / g, a molecular weight of 9200, a brand name of JONCRYLHPD 196, and is supplied by BASF of Germany.

[0015] The present invention selects a dispersant with an acid value of 180-210 mgKOH / g and a molecular weight of 8,000-12,000, particularly JONCRYL HPD 196. This is primarily due to the high acid value and abundance of acidic functional groups in its molecular structure, which form strong electrostatic repulsion and hydrogen bonding with polar groups or active sites on the surfaces of Pigment Yellow 74 and Pigment Yellow 155. This allows for effective adsorption onto the pigment particle surfaces, providing excellent dispersion stability. Furthermore, JONCRYL HPD 196 has a moderate molecular weight. In the aqueous system of the self-dispersing colorant, adsorption onto the pigment particle surfaces of the pigment particles charges the pigment particles, increasing electrostatic repulsion between the particles, preventing aggregation and sedimentation, and ensuring the long-term stability of the colorant. In addition, the adsorption layer of its molecular chain on the pigment surface can also play a steric hindrance role, further enhancing the dispersion stability of the pigment particles, reducing the sedimentation and flocculation of the pigment particles during storage and use, and ensuring the consistency of the performance of the self-dispersing colorant.

[0016] As an implementable case, the mass ratio of the dispersant to Pigment Yellow 74 is (0.5-1):(30-40).

[0017] As an implementable case, the high-speed dispersion speed is 600-1000 rpm and the time is 1-3 hours.

[0018] As an practicable case, the grinding time is 10-12 hours.

[0019] A second aspect of the present invention provides a Pigment Yellow 74 self-dispersible color paste prepared by the method for preparing the Pigment Yellow 74 self-dispersible color paste.

[0020] Beneficial effects

[0021] (1) The present invention mainly utilizes the hydrolyzate of Pigment Yellow 155 as a dispersant and crystallization inhibitor, which significantly improves the dispersibility of Pigment Yellow 74, reduces agglomeration, and enhances the stability of the self-dispersing color paste.

[0022] (2) Compared with the traditional low-temperature diazo coupling reaction for preparing color paste, the preparation method provided in the present invention is simpler, does not require complex equipment, is suitable for actual production applications, and avoids the wastewater problem generated in the traditional modification process, which is more in line with environmental protection requirements.

[0023] (3) The present invention selects a specific dispersant with an acid value of 180-210 mgKOH / g and a molecular weight of 8000-12000, which can further improve the stability and coloring performance of the self-dispersing color paste.

[0024] (IV) The self-dispersing pigment yellow 74 prepared by the present invention has a high surface tension of up to 50 mN / m, which is superior to traditional grinding paste and broadens the scope of application in ink formulations.

[0025] (5) The self-dispersible pigment yellow 74 prepared by the present invention has excellent coloring properties, with higher color density, more vivid colors, and high color yield efficiency, significantly saving ink costs and improving print clarity. Furthermore, the self-dispersible pigment paste exhibits good filterability, uniform dispersion, and a short filterability test time, resulting in fine particles and excellent dispersion. After aging at 60°C for 7 days, the self-dispersible pigment paste maintains stable viscosity, conductivity, and filterability, with no precipitation or stratification, making it suitable for long-term storage and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the coloring effect of the Pigment Yellow 74 self-dispersible color paste in Example 1.

[0027] Figure 2 Schematic diagram of the coloring effect of Pigment Yellow 74 ground paste in Comparative Example 1. DETAILED DESCRIPTION

[0028] The raw material information involved in Examples 1-5 of the present invention and Comparative Example 1 is as described in Table 1. If not mentioned in the table, it is a common commercially available product.

[0029] Table 1

[0030] supplier model Pigment Yellow 155 Clariant Chemicals (China) Co., Ltd. Graphtol Yellow 3GP Joncryl HPD 196 dispersant BASF of Germany Joncryl HPD 196 Joncryl HPD 96 dispersant BASF of Germany Joncryl HPD 96 DX778 dispersant Nanjing Yihua High-tech Technology Co., Ltd. DX778 DX517 wetting agent Nanjing Yihua High-tech Technology Co., Ltd. DX517 FX2907 defoaming agent Nanjing Yihua High-tech Technology Co., Ltd. FX2907 Pigment Yellow 74 Zhejiang Shengda Xiangwei Chemical Co., Ltd. Permanent Yellow 5GX

[0031] Example 1

[0032] The first aspect of this example provides a method for preparing a self-dispersible pigment yellow 74 paste, specifically comprising:

[0033] S1. Hydrolysis of Pigment Yellow 155: 100 g of Pigment Yellow 155 and 60 g of a 2.5 mol / L sodium hydroxide aqueous solution were mixed and reacted at 70° C. with stirring for 3 h to obtain a Pigment Yellow 155 hydrolyzate solution. The Pigment Yellow 155 hydrolyzate solution was centrifuged to remove unreacted Pigment Yellow 155 solids. The reaction solution was then neutralized with dilute hydrochloric acid to a pH of 6.5 to obtain a Pigment Yellow 155 hydrolyzate precipitate. The Pigment Yellow 155 hydrolyzate precipitate was washed with deionized water and dried to constant weight to obtain Pigment Yellow 155 hydrolyzate.

[0034] S2. Preparation of Pigment Yellow 74 Self-Dispersible Color Paste: 30 g of Pigment Yellow 74, 3 g of Pigment Yellow 155 hydrolyzate, and 0.5 g of dispersant Joncryl HPD 196 were mixed, and 166.5 mL of deionized water was added and stirred evenly. The mixture was then dispersed in a high-speed disperser at 800 rpm for 1 hour, and then ground in a grinder for 12 hours. The mixture was desalted, purified, and concentrated to obtain Pigment Yellow 74 Self-Dispersible Color Paste.

[0035] In a second aspect of this example, a self-dispersible pigment yellow 74 color paste is provided, which is prepared by the above-mentioned method for preparing the self-dispersible pigment yellow 74 color paste.

[0036] The coloring effect diagram of the pigment yellow 74 self-dispersible color paste prepared in this example is as follows Figure 1 shown.

[0037] Example 2

[0038] The first aspect of this example provides a method for preparing a self-dispersible pigment yellow 74 paste, specifically comprising:

[0039] S1. Hydrolysis of Pigment Yellow 155: 100 g of Pigment Yellow 155 and 75 g of a 2.5 mol / L aqueous sodium hydroxide solution were mixed, and the mixture was stirred and reacted at 100° C. for 5 h to obtain a Pigment Yellow 155 hydrolyzate solution. The hydrolyzate solution was centrifuged to remove unreacted Pigment Yellow 155 solids, and the reaction solution was neutralized with dilute hydrochloric acid to pH 7 to obtain a Pigment Yellow 155 hydrolyzate precipitate. The Pigment Yellow 155 hydrolyzate precipitate was washed with deionized water and dried to constant weight to obtain Pigment Yellow 155 hydrolyzate;

[0040] S2. Preparation of Pigment Yellow 74 Self-Dispersible Color Paste: 30 g of Pigment Yellow 74, 4.5 g of Pigment Yellow 155 hydrolyzate, and 1 g of dispersant Joncryl HPD 196 were mixed, and 164.5 mL of deionized water was added and stirred evenly. The mixture was then dispersed in a high-speed disperser at 800 rpm for 1 hour, and then ground in a grinder for 10 hours. The mixture was desalted, purified, and concentrated to obtain Pigment Yellow 74 Self-Dispersible Color Paste.

[0041] In a second aspect of this example, a self-dispersible pigment yellow 74 color paste is provided, which is prepared by the above-mentioned method for preparing the self-dispersible pigment yellow 74 color paste.

[0042] Example 3

[0043] The first aspect of this example provides a method for preparing a self-dispersible pigment yellow 74 paste, specifically comprising:

[0044] S1. Hydrolysis of Pigment Yellow 155: 100 g of Pigment Yellow 155 and 75 g of a 2.5 mol / L aqueous sodium hydroxide solution were mixed, and the mixture was stirred and reacted at 100° C. for 5 h to obtain a Pigment Yellow 155 hydrolyzate solution. The hydrolyzate solution was centrifuged to remove unreacted Pigment Yellow 155 solids, and the reaction solution was neutralized with dilute hydrochloric acid to pH 7 to obtain a Pigment Yellow 155 hydrolyzate precipitate. The Pigment Yellow 155 hydrolyzate precipitate was washed with deionized water and dried to constant weight to obtain Pigment Yellow 155 hydrolyzate;

[0045] S2. Preparation of Pigment Yellow 74 Self-Dispersible Color Paste: 30g of Pigment Yellow 74, 2g of Pigment Yellow 155 hydrolyzate, and 0.5g of Joncoyl HPD 196 dispersant were mixed and uniformly stirred with 168.5mL of deionized water. The mixture was then dispersed in a high-speed disperser at 800 rpm for 1 hour and then ground in a grinder for 8 hours. The viscosity of the material increased, clogging the grinder and preventing further grinding. The experiment failed.

[0046] Example 4

[0047] The first aspect of this example provides a method for preparing a self-dispersible pigment yellow 74 paste, specifically comprising:

[0048] S1. Hydrolysis of Pigment Yellow 155: 100 g of Pigment Yellow 155 and 75 g of a 2.5 mol / L aqueous sodium hydroxide solution were mixed, and the mixture was stirred and reacted at 100° C. for 5 h to obtain a Pigment Yellow 155 hydrolyzate solution. The hydrolyzate solution was centrifuged to remove unreacted Pigment Yellow 155 solids, and the reaction solution was neutralized with dilute hydrochloric acid to pH 7 to obtain a Pigment Yellow 155 hydrolyzate precipitate. The Pigment Yellow 155 hydrolyzate precipitate was washed with deionized water and dried to constant weight to obtain Pigment Yellow 155 hydrolyzate;

[0049] S2. Preparation of Pigment Yellow 74 Self-Dispersible Color Paste: 30g of Pigment Yellow 74, 2g of Pigment Yellow 155 hydrolyzate, and 1g of Joncoyl HPD 196 dispersant were mixed and uniformly stirred with 168mL of deionized water. The mixture was then dispersed in a high-speed disperser at 800rpm for 1 hour and then ground in a grinder for 10 hours. The viscosity of the material increased, clogging the grinder and preventing further grinding. The experiment failed.

[0050] Example 5

[0051] The first aspect of this example provides a method for preparing a self-dispersible pigment yellow 74 paste, specifically comprising:

[0052] S1. Hydrolysis of Pigment Yellow 155: 100 g of Pigment Yellow 155 and 75 g of a 2.5 mol / L aqueous sodium hydroxide solution were mixed, and the mixture was stirred and reacted at 100° C. for 5 h to obtain a Pigment Yellow 155 hydrolyzate solution. The hydrolyzate solution was centrifuged to remove unreacted Pigment Yellow 155 solids, and the reaction solution was neutralized with dilute hydrochloric acid to pH 7 to obtain a Pigment Yellow 155 hydrolyzate precipitate. The Pigment Yellow 155 hydrolyzate precipitate was washed with deionized water and dried to constant weight to obtain Pigment Yellow 155 hydrolyzate;

[0053] S2. Preparation of Pigment Yellow 74 Self-Dispersible Color Paste: 30g of Pigment Yellow 74, 3g of Pigment Yellow 155 hydrolyzate, and 0.5g of Joncoyl HPD 96 dispersant were mixed and uniformly stirred with 164mL of deionized water. The mixture was then dispersed in a high-speed disperser at 800rpm for 1 hour and then ground in a grinder for 7 hours. The viscosity of the material increased, clogging the grinder and preventing further grinding. The experiment failed.

[0054] Comparative Example 1

[0055] The first aspect of this example provides a method for preparing a pigment yellow 74 grinding paste, specifically comprising:

[0056] Mix 20.5 g of DX778 dispersant, 0.3 g of DX517 wetting agent, 0.4 g of FX2907 defoamer, and 30 g of Pigment Yellow 74, add 148.8 mL of deionized water, stir evenly, disperse in a high-speed disperser at 800 rpm for 60 min, and then grind in a grinder for 15 h to obtain Pigment Yellow 74 ground color paste.

[0057] In a second aspect of this example, a Pigment Yellow 74 mill base is provided, which is prepared by the above-mentioned method for preparing the Pigment Yellow 74 mill base.

[0058] The coloring effect diagram of the pigment yellow 74 ground paste prepared in this example is as follows Figure 2 shown.

[0059] Performance Testing

[0060] The following performance tests were performed on the Pigment Yellow 74 self-dispersible color pastes prepared in Example 1 and Example 2 and the Pigment Yellow 74 grinding color paste prepared in Comparative Example 1.

[0061] 1. Color density test method: 3 drops of each of the color pastes of Examples 1-2 and Comparative Example 1 were placed on the surface of A4 paper, and the paper was evenly scraped downward with a glass rod. After drying, the color density was tested with a color densitometer. The experimental results are shown in Table 2.

[0062] 2. Filterability Test Method: Filter 200g of Pigment Yellow 74 paste through a 0.45μm PP film under a vacuum of 0.09MPa. Record the filtration time. A filter less than 40s is considered acceptable. See Table 3 for detailed test results. The presence of few impurities on the filter paper indicates that the paste is evenly dispersed, contains few solid particles, and has good dispersibility and filterability.

[0063] 3. Aging Test Method: Place Pigment Yellow 74 paste in a 60°C oven for 7 days. Then remove and allow to cool to room temperature (25°C). Test standard parameters, including viscosity at 25°C, conductivity, surface tension, and filterability. There should be no precipitation or delamination. The filterability test should be completed within 40 seconds. See Table 3 for detailed test results.

[0064] Table 2

[0065]

[0066] Table 3

[0067] Example 1 Example 2 Comparative Example 1 Color density 1.197 1.138 0.957 L* 73.55 69.78 72.95 a* -7.01 -5.25 -5.19 b* 82.66 78.98 72.57

[0068] Among them, L* represents brightness or lightness. The lower the L value, the darker and darker the color.

[0069] a* represents the color's position on the red-green axis. A positive a value indicates a color leaning toward red, while a negative a value indicates a color leaning toward green.

[0070] b* represents the color's position on the yellow-blue axis. A positive b value indicates a yellowish color, while a negative b value indicates a blueish color.

[0071] As can be seen from the experimental results in Tables 2 and 3, the conductivity of the self-dispersible pigment pastes prepared in Examples 1-2 of the present invention is lower than that in Comparative Example 1. This indicates that the self-dispersible pigment pastes in Examples 1-2 have lower viscosity and conductivity than the ground pigment pastes, higher surface tension, and are more suitable and convenient for use in ink applications. Furthermore, the self-dispersible pigment pastes in Examples 1-2 exhibit excellent filterability stability after aging, a higher and more vivid color density than the ground pigment pastes, high color yield efficiency, greater ink conservation, and clearer, more expressive printing.

Claims

1. A self-dispersing paste of Pigment Yellow 74, characterized in that: include: S1. Mix Pigment Yellow 155 and an alkaline aqueous solution, stir and react for 1-3 hours to obtain a Pigment Yellow 155 hydrolyzate solution, then filter out the unreacted Pigment Yellow 155, adjust the pH of the reaction solution to 6-7, obtain a Pigment Yellow 155 hydrolyzate precipitate, wash with water, and dry to constant weight to obtain Pigment Yellow 155 hydrolyzate; S2. Mix the hydrolyzate of Pigment Yellow 74 and Pigment Yellow 155 with a dispersant, add water and stir evenly, then disperse at high speed, grind, desalt, purify and concentrate to obtain a self-dispersible color paste of Pigment Yellow 74.

2. The self-dispersible color paste of Pigment Yellow 74 according to claim 1, characterized in that The reaction temperature in step S1 is 70-100°C.

3. The self-dispersing color paste of Pigment Yellow 74 according to claim 1, characterized in that The alkaline aqueous solution includes a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution.

4. The self-dispersible color paste of Pigment Yellow 74 according to claim 3, characterized in that The molar concentration of the sodium hydroxide aqueous solution is 1-4 mol / L.

5. The self-dispersible color paste of Pigment Yellow 74 according to claim 1, characterized in that The mass ratio of the pigment yellow 74 to the pigment yellow 155 hydrolyzate in step S2 is 1:(0.1-0.15).

6. The self-dispersible color paste of Pigment Yellow 74 according to claim 1, characterized in that The acid value of the dispersant is 180-210 mgKOH / g and the molecular weight is 8000-12000.

7. The self-dispersible color paste of Pigment Yellow 74 according to claim 1, characterized in that The mass ratio of the dispersant to Pigment Yellow 74 in step S2 is (0.5-1):(30-40).

8. The self-dispersible color paste of Pigment Yellow 74 according to claim 1, characterized in that The stirring speed of the high-speed dispersion is 600-1000 rpm, and the time is 1-3 hours.

9. The self-dispersible color paste of Pigment Yellow 74 according to claim 8, characterized in that The grinding time is 10-12 hours.

10. A Pigment Yellow 74 self-dispersible color paste prepared according to the method for preparing the Pigment Yellow 74 self-dispersible color paste according to any one of claims 1 to 9.

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