Surface modified pre-dispersed pigment and modification method

Abstract

The invention discloses a surface modified pre-dispersed pigment and a modification method. Comprising the following steps: step 1, stirring and mixing a copper phthalocyanine pigment, lauryl sodium sulfate and deionized water to obtain a pigment dispersion liquid; 2, styrene, the modified monomer, n-hexadecane, 2, 2 '-azobisisobutyronitrile and lauryl sodium sulfate are mixed, and a monomer microemulsion is obtained; and 3, adding the monomer microemulsion into the pigment dispersion liquid, carrying out ultrasonic stirring, and carrying out heating reaction to obtain the pre-dispersed pigment. The preparation method has the beneficial effects that corresponding polystyrene is synthesized through a free radical polymerization reaction and uniformly coats the surfaces of pigment particles to form a protective layer, so that direct contact among the pigment particles is effectively reduced, aggregation is prevented, and good dispersity of the pigment in water is kept; meanwhile, monomers synthesized by polystyrene are correspondingly modified, so that the stability and antibacterial ability of the pigment are further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical dyes, and specifically relates to surface-modified pre-dispersed pigments and modification methods. Background Art

[0002] As an advanced form of pigments, pre-dispersed pigments have significant advantages. By pre-dispersing pigment particles in a carrier, it can effectively improve the dispersion efficiency of pigments, reduce grinding and stirring time, thereby reducing production costs. In addition, pre-dispersed pigments can quickly and evenly blend into the matrix material during use, significantly improving the coloring performance and gloss performance of pigments, while reducing pigment agglomeration and enhancing the appearance quality of products.

[0003] However, the pre-dispersed pigments in the prior art still have some deficiencies. Although the pre-dispersion process can improve the initial dispersion state of pigments, under long-term storage or complex processing conditions, pigment particles are prone to re-aggregation, resulting in a decrease in dispersion stability. In addition, traditional pre-dispersed pigments have poor antibacterial properties and are difficult to meet the requirements of fields with high hygiene requirements such as food packaging and medical and health. At the same time, the adaptability of pre-dispersed pigments in different media is limited. Especially in polar or non-polar solvent systems, the dispersion of pigments may be affected by surface tension differences. In addition, in multiple freeze-thaw cycles or high-low temperature alternating environments, the size of pigment particles is prone to change, further exacerbating the aggregation phenomenon, thus affecting their long-term use stability.

[0004] Therefore, to solve the above problems, the present invention provides a surface-modified pre-dispersed pigment and a modification method. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a surface-modified pre-dispersed pigment and a modification method.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A modification method for surface-modified pre-dispersed pigments includes the following steps:

[0008] Step 1: Stir and mix copper phthalocyanine pigment, sodium dodecyl sulfate, and deionized water, homogenize for 15 - 20 min, and then perform ultrasonic treatment to obtain a pigment dispersion liquid;

[0009] Step 2: Mix styrene, modified monomer, n-hexadecane, 2,2'-azobisisobutyronitrile, and sodium dodecyl sulfate, then transfer it to deionized water, stir for 1 - 2 h for pre-emulsification, and then perform ultrasonic treatment for 3 - 5 min to obtain a monomer microemulsion;

[0010] Step 3: Add the monomer microemulsion to the pigment dispersion, stir ultrasonically for 10 - 20 min, then heat up to 70 - 80 °C, and react for 12 - 13 h under a protective atmosphere to obtain the pre-dispersed pigment.

[0011] Preferably, the mass ratio of the pigment dispersion to the monomer microemulsion is 4:(1 - 1.5).

[0012] Preferably, the pigment dispersion comprises the following components: by weight, 50 - 80 parts of copper phthalocyanine pigment, 5 - 7 parts of sodium dodecyl sulfate, and 400 - 450 parts of deionized water;

[0013] The monomer microemulsion comprises the following components: by weight, 15 - 18 parts of styrene, 6 - 8 parts of modified monomer, 0.6 - 0.8 parts of n-hexadecane, 0.3 - 0.5 parts of 2,2'-azobisisobutyronitrile, 1 - 2 parts of sodium dodecyl sulfate, and 100 - 120 parts of deionized water.

[0014] Preferably, the preparation process of the modified monomer is as follows:

[0015] S1: Mix p-nitrobenzaldehyde, 4-bromomethyl-5H-furan-2-one, diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate, and dichloromethane, stir for 30 - 40 min, add the catalyst L-proline, react at room temperature for 12 - 13 h, after purification, mix with ammonium chloride, methanol, iron powder, and deionized water, stir ultrasonically for 10 - 20 min, heat up to 80 - 90 °C, react for 3 - 4 h, rotary evaporate to remove the solvent, cool, filter, wash, and dry to obtain intermediate A;

[0016] S2: Mix 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, ethyl chloroacetate, acetonitrile, and potassium carbonate, heat up to 80 - 90 °C, react for 7 - 8 h, cool to room temperature, add N-bromosuccinimide and p-toluenesulfonic acid, stir evenly, then heat up to 60 - 80 °C, react for 15 - 20 min to obtain intermediate B;

[0017] S3: Mix anthranilic acid, phenyl isocyanate, acetone, and triethylamine, react at room temperature for 1 - 2 h, after purification, add to ethanol with intermediate B, react at room temperature for 4 - 5 h, filter, wash, and dry, then transfer to a mixed solvent of methanol and dichloromethane, add sodium hydroxide solution, react for 1 - 2 h, adjust the pH to 3 - 4, and perform post-treatment to obtain intermediate C;

[0018] S4: Mix intermediate A, intermediate C, and dimethylformamide, add dicyclohexylcarbodiimide, heat up to 70 - 80 °C, react for 4 - 5 h, cool to room temperature, and perform post-treatment to obtain the modified monomer.

[0019] In the scheme, 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester can combine with the aldehyde group in p-nitrobenzaldehyde to form a stable imine intermediate, which can further undergo a reductive alkylation reaction with 4-bromomethyl-5H-furan-2-one, and in the presence of iron powder and ammonium chloride, the nitro group contained in it is further reduced to an amino group, thereby obtaining intermediate A. The specific reaction process is shown below:

[0020]

[0021] In the scheme, potassium carbonate provides an alkaline environment, and the phenolic hydroxyl group in 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone is deprotonated in acetonitrile to generate a highly nucleophilic phenoloxy anion, which then attacks the chlorine atom in ethyl chloroacetate to form a new ether bond through an SN2 reaction; then N-bromosuccinimide (NBS) decomposes under heating conditions to generate a bromine radical (Br·), which captures the hydrogen atom on the α-carbon of the acetyl group through a free radical chain reaction, thereby obtaining an intermediate B; the specific reaction process is shown below:

[0022]

[0023] In the scheme, the amino group of anthranilic acid attacks the carbon atom of phenyl isocyanate to form an unstable intermediate, and then a molecule of water is removed by intramolecular cyclization to form a skeleton. The specific reaction process is as follows:

[0024]

[0025] The thiol group in the skeleton acts as a nucleophile to attack the bromine carbon atom of intermediate B to undergo an SN2 reaction to form a thioether bond; then, under alkaline conditions, the ester group contained is hydrolyzed; the specific reaction process is as follows:

[0026]

[0027] In the scheme, the amino group contained in the intermediate A acts as a nucleophilic agent to attack the activated carboxylic acid to form a new amide bond, thereby finally obtaining a modified monomer; the structure of the modified monomer is shown below:

[0028]

[0029] Preferably, the raw materials of intermediate A include the following components: by weight, 2-3 parts of p-nitrobenzaldehyde, 0.5-1 part of 4-bromomethyl-5H-furan-2-one, 1-2 parts of diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate, 40-50 parts of dichloromethane, 0.1-0.2 part of L-proline, 1-2 parts of ammonium chloride, 60-70 parts of methanol, 0.3-0.5 part of iron powder, and 10-12 parts of deionized water.

[0030] Preferably, the raw materials of intermediate B include the following components: by weight, 10-12 parts of 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, 8-10 parts of ethyl chloroacetate, 60-80 parts of acetonitrile, 0.1-0.2 part of potassium carbonate, 2-3 parts of N-bromosuccinimide, and 0.1-0.2 part of p-toluenesulfonic acid.

[0031] Preferably, the raw materials of intermediate C include the following components: by weight, 12-15 parts of anthranilic acid, 10-12 parts of phenyl isocyanate, 60-70 parts of acetone, 0.1-0.2 part of triethylamine, 8-10 parts of intermediate B, 40-50 parts of ethanol, 8-10 parts of a mixed solvent of methanol and dichloromethane, and 4-5 parts of sodium hydroxide solution.

[0032] Preferably, the raw materials of the modified monomer include the following components: by weight, 6-8 parts of intermediate A, 10-12 parts of intermediate C, 70-80 parts of dimethylformamide, and 0.1-0.2 part of dicyclohexylcarbodiimide.

[0033] Advantages of the present invention:

[0034] In the present invention, the corresponding polystyrene is synthesized by free radical polymerization reaction, which uniformly coats the surface of pigment particles to form a protective layer, effectively reducing the direct contact between pigment particles, thereby preventing aggregation and maintaining good dispersibility of the pigment in water; meanwhile, the monomers for synthesizing polystyrene are correspondingly modified to further improve the stability and antibacterial ability of the pigment. Specifically as follows:

[0035] First: The density of polystyrene is much lower than that of copper phthalocyanine pigment; through coating, the density of the formed core-shell structure is reduced, so that the sedimentation rate of the pigment in water slows down, thereby improving its dispersibility and stability during the dyeing process; moreover, the surface of polystyrene carries a certain charge, forming an electrostatic repulsive force between pigment particles, further preventing particle aggregation and improving dispersibility;

[0036] Second: In the solution, the modified monomer used for synthesizing polystyrene contains a large number of conjugated systems, and the CuPc molecule also has an aromatic ring structure, enabling the two to have a π-π interaction, further enhancing the binding force; this interaction makes the adsorption of the monomer on the surface of CuPc more stable, and the coating effect is further improved;

[0037] Third: In the solution, the synthesized modified monomer uses a quinazolinone ring as the backbone, introducing antibacterial structures such as halogen groups and butenolide, effectively improving the antibacterial ability of the material; at the same time, the aromaticity and conjugated system of the quinazolinone ring enable the synthesized polystyrene to remain stable in various environments, expanding the application scenarios of the material. Specific Embodiments

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0039] Example 1: A method for surface-modifying and pre-dispersing pigments, comprising the following steps:

[0040] Step 1: Stir and mix 50 parts of copper phthalocyanine pigment, 5 parts of sodium dodecyl sulfate, and 400 parts of deionized water, homogenize for 15 min, and then perform ultrasonic treatment to obtain a pigment dispersion;

[0041] Step 2: Mix 15 parts of styrene, 6 parts of modified monomer, 0.6 part of n-hexadecane, 0.3 part of 2,2'-azobisisobutyronitrile, and 1 part of sodium dodecyl sulfate, then transfer to 100 parts of deionized water, stir for 1 h for pre-emulsification, and then perform ultrasonic treatment for 3 min to obtain a monomer microemulsion;

[0042] Step 3: Add the monomer microemulsion to the pigment dispersion (the mass ratio of the pigment dispersion to the monomer microemulsion is 4:1), stir ultrasonically for 10 min, then raise the temperature to 70 °C, and react for 12 h under a protective atmosphere to obtain pre-dispersed pigment;

[0043] Among them, the preparation process of the modified monomer is:

[0044] S1: Mix 2 parts of p-nitrobenzaldehyde, 0.5 part of 4-bromomethyl-5H-furan-2-one, 1 part of diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate, and 40 parts of dichloromethane, stir for 30 min, add 0.1 part of L-proline as a catalyst, react at room temperature for 12 h, after purification, mix with 1 part of ammonium chloride, 60 parts of methanol, 0.3 part of iron powder, and 10 parts of deionized water, stir ultrasonically for 10 min, heat up to 80 °C, react for 3 h, remove the solvent by rotary evaporation, filter, wash, and dry after cooling to obtain intermediate A;

[0045] S2: Mix 10 parts of 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, 8 parts of ethyl chloroacetate, 60 parts of acetonitrile, and 0.1 part of potassium carbonate, heat up to 80 °C, react for 7 h, cool to room temperature, add 2 parts of N-bromosuccinimide and 0.1 part of p-toluenesulfonic acid, stir evenly and then heat up to 60 °C, react for 15 min to obtain intermediate B;

[0046] S3: Mix 12 parts of anthranilic acid, 10 parts of phenyl isocyanate, 60 parts of acetone, and 0.1 part of triethylamine, react at room temperature for 1 h, after purification, add 8 parts of intermediate B to 40 parts of ethanol, react at room temperature for 4 h, filter, wash, and dry, then transfer to a mixed solvent of 8 parts of methanol and dichloromethane, add 4 parts of sodium hydroxide solution (2 mol / L, solvent is methanol), react for 1 h, adjust the pH to 3, and perform post-treatment to obtain intermediate C;

[0047] S4: Mix 6 parts of intermediate A, 10 parts of intermediate C, and 70 parts of dimethylformamide, add 0.1 part of dicyclohexylcarbodiimide, heat up to 70 °C, react for 4 h, cool to room temperature, and perform post-treatment to obtain the modified monomer.

[0048] Example 2: The method for modifying the surface-modified pre-dispersed pigment includes the following steps:

[0049] Step 1: Stir and mix 80 parts of copper phthalocyanine pigment, 7 parts of sodium dodecyl sulfate, and 450 parts of deionized water, homogenize for 20 min, and then perform ultrasonic treatment to obtain a pigment dispersion;

[0050] Step 2: Mix 18 parts of styrene, 8 parts of the modified monomer, 0.8 part of n-hexadecane, 0.5 part of 2,2'-azobisisobutyronitrile, and 2 parts of sodium dodecyl sulfate, then transfer to 120 parts of deionized water, stir for 2 h for pre-emulsification, and then perform ultrasonic treatment for 5 min to obtain a monomer microemulsion;

[0051] Step 3: Add the monomer microemulsion to the pigment dispersion (the mass ratio of the pigment dispersion to the monomer microemulsion is 4:1.5), stir ultrasonically for 20 min, then heat up to 80 °C, and react for 13 h under a protective atmosphere to obtain the pre-dispersed pigment;

[0052] Among them, the preparation process of the modified monomer is as follows:

[0053] S1: Mix 3 parts of p-nitrobenzaldehyde, 1 part of 4-bromomethyl-5H-furan-2-one, 2 parts of diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate, and 50 parts of dichloromethane, stir for 40 min, add 0.2 part of L-proline as a catalyst, react at room temperature for 13 h, after purification, mix with 2 parts of ammonium chloride, 70 parts of methanol, 0.5 part of iron powder, and 12 parts of deionized water, stir ultrasonically for 20 min, heat up to 90 °C, react for 4 h, evaporate the solvent by rotary evaporation, filter, wash, and dry after cooling to obtain intermediate A;

[0054] S2: Mix 12 parts of 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, 10 parts of ethyl chloroacetate, 80 parts of acetonitrile, and 0.2 part of potassium carbonate, heat up to 90 °C, react for 8 h, cool to room temperature, add 3 parts of N-bromosuccinimide and 0.2 part of p-toluenesulfonic acid, stir evenly and then heat up to 80 °C, react for 20 min to obtain intermediate B;

[0055] S3: Mix 15 parts of anthranilic acid, 12 parts of phenyl isocyanate, 70 parts of acetone, and 0.2 part of triethylamine, react at room temperature for 2 h, after purification, add 10 parts of intermediate B to 50 parts of ethanol, react at room temperature for 5 h, filter, wash, and dry, then transfer to a mixed solvent of 10 parts of methanol and dichloromethane, add 5 parts of sodium hydroxide solution (2 mol / L, solvent is methanol), react for 2 h, adjust the pH to 4, and perform post-treatment to obtain intermediate C;

[0056] S4: Mix 8 parts of intermediate A, 12 parts of intermediate C, and 80 parts of dimethylformamide, add 0.2 part of dicyclohexylcarbodiimide, heat up to 80 °C, react for 5 h, cool to room temperature, and perform post-treatment to obtain the modified monomer.

[0057] Example 3: The method for modifying a surface-modified pre-dispersed pigment includes the following steps:

[0058] Step 1: Stir and mix 65 parts of copper phthalocyanine pigment, 6 parts of sodium dodecyl sulfate, and 425 parts of deionized water, homogenize for 17.5 min, and then perform ultrasonic treatment to obtain a pigment dispersion;

[0059] Step 2: Mix 16.5 parts of styrene, 7 parts of the modified monomer, 0.7 part of n-hexadecane, 0.4 part of 2,2'-azobisisobutyronitrile, and 1.5 parts of sodium dodecyl sulfate, then transfer to 110 parts of deionized water, stir for 1.5 h for pre-emulsification, and then perform ultrasonic treatment for 4 min to obtain a monomer microemulsion;

[0060] Step 3: Add the monomer microemulsion to the pigment dispersion (the mass ratio of the pigment dispersion to the monomer microemulsion is 4:1.25), stir ultrasonically for 15 min, then heat up to 75 °C, and react for 12.5 h under a protective atmosphere to obtain the pre-dispersed pigment;

[0061] Among them, the preparation process of the modified monomer is as follows:

[0062] S1: Mix 2.5 parts of p-nitrobenzaldehyde, 0.75 part of 4-bromomethyl-5H-furan-2-one, 1.5 parts of diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate, and 45 parts of dichloromethane, stir for 35 min, add 0.15 part of the catalyst L-proline, react at room temperature for 12.5 h, after purification, mix with 1.5 parts of ammonium chloride, 65 parts of methanol, 0.4 part of iron powder, and 11 parts of deionized water, stir ultrasonically for 15 min, heat up to 85 °C, react for 3.5 h, remove the solvent by rotary evaporation, filter, wash, and dry after cooling to obtain intermediate A;

[0063] S2: Mix 11 parts of 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, 9 parts of ethyl chloroacetate, 70 parts of acetonitrile, and 0.15 part of potassium carbonate, heat up to 85 °C, react for 7.5 h, cool to room temperature, add 2.5 parts of N-bromosuccinimide and 0.15 part of p-toluenesulfonic acid, stir evenly and then heat up to 70 °C, react for 17.5 min to obtain intermediate B;

[0064] S3: Mix 13.5 parts of anthranilic acid, 11 parts of phenyl isocyanate, 65 parts of acetone, and 0.15 part of triethylamine, react at room temperature for 1.5 h, after purification, add 9 parts of intermediate B to 45 parts of ethanol, react at room temperature for 4.5 h, filter, wash, and dry, then transfer to a mixed solvent of 9 parts of methanol and dichloromethane, add 4.5 parts of sodium hydroxide solution (2 mol / L, solvent is methanol), react for 1.5 h, adjust the pH to 3.5, and perform post-treatment to obtain intermediate C;

[0065] S4: Mix 7 parts of intermediate A, 11 parts of intermediate C, and 75 parts of dimethylformamide, add 0.15 part of dicyclohexylcarbodiimide, heat up to 75 °C, react for 4.5 h, cool to room temperature, and perform post-treatment to obtain the modified monomer.

[0066] Comparative Example 1: Without adding the modified monomer, coat the copper phthalocyanine pigment, and the rest is the same as in Example 3, specifically as follows:

[0067] Step 1: Stir and mix 65 parts of copper phthalocyanine pigment, 6 parts of sodium dodecyl sulfate, and 425 parts of deionized water, homogenize for 17.5 min, and then perform ultrasonic treatment to obtain the pigment dispersion;

[0068] Step 2: 16.5 parts of styrene, 0.7 parts of n-hexadecane, 0.4 parts of 2,2'-azobisisobutyronitrile, and 1.5 parts of sodium dodecyl sulfate were mixed, and then transferred to 110 parts of deionized water, stirred for 1.5 hours for pre-emulsification, and then ultrasonically treated for 4 minutes to obtain a monomer microemulsion;

[0069] Step 3: Add the monomer microemulsion to the pigment dispersion (the mass ratio of the pigment dispersion to the monomer microemulsion is 4:1.25), ultrasonically stir for 15 minutes, then heat to 75°C, react for 12.5 hours under a protective atmosphere to obtain a pre-dispersed pigment.

[0070] Comparative Example 2: Copper phthalocyanine is not coated, as follows:

[0071] 5 parts of copper phthalocyanine pigment were added to 44.5 parts of deionized water containing 0.5 parts of sodium dodecyl sulfate (SDS); the mixture was homogenized using a mechanical disperser at a speed of 20,000 rpm for 15 minutes, and after ultrasonic treatment, a pre-dispersed pigment was obtained.

[0072] The mixture was immediately stirred at 2000 rpm for 2 h.

[0073] Detection test: (1) The pre-dispersed pigment obtained in the embodiment and the comparative example was centrifuged at 4000rpm for 30 minutes. After centrifugation, 0.05mL of the supernatant in the centrifuge tube was taken and diluted with deionized water. The absorbance of the dilution at the maximum absorption wavelength was measured using a UV-visible spectrometer, and the relative absorbance was calculated; (2) The pre-dispersed pigment obtained in the embodiment and the comparative example was sealed in a glass bottle, placed in a -10°C freezer for 24 hours, and then heated at 60°C for 24 hours to complete a freeze-thaw cycle. The freeze-thaw cycle was repeated 5 times. Before and after the cycle, the average particle size of the particles in the dispersion was measured, and the size change rate was calculated; (3) The pre-dispersed pigment obtained in the embodiment and the comparative example was fully mixed with the bacterial solution, cultured for 48 hours, and the antibacterial rate was measured; the obtained data are shown in the following table:

[0074]

[0075] Conclusion: Through the surface modification of pre-dispersed pigments and its modification method, the present invention significantly improves the dispersibility, stability and antibacterial properties of pigments. From the experimental data, after centrifugation in Examples 1 to 3, the relative absorbance is between 88.4% and 90.1%, much higher than 70% and 65% in Comparative Examples 1 and 2, indicating that the modified pigments have better stability and dispersibility in water. In terms of the size change rate, the size change rate in the examples is between 25.4% and 26.7%, while the size change rates in Comparative Examples 1 and 2 are 60.7% and 65.6% respectively, indicating that the particle size of the modified pigments changes less after multiple freeze-thaw cycles and has higher stability. In the antibacterial performance test, the antibacterial rates of the examples against Escherichia coli all reach over 99.8%, while the antibacterial rates in Comparative Examples 1 and 2 are 91.7% and 88.8% respectively, which shows that the introduction of the modified monomer significantly enhances the antibacterial ability of the pigments. In summary, the surface-modified pre-dispersed pigments and their modification method of the present invention have significant advantages in improving the dispersibility, stability and antibacterial properties of pigments.

[0076] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0077] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A surface modified pre-dispersed pigment modification method, characterized in that: The following steps are involved: Step 1: Mix copper phthalocyanine pigment, sodium dodecyl sulfate and deionized water, homogenize for 15-20 minutes, and then ultrasonically treat to obtain a pigment dispersion; Step 2: Styrene, modified monomer, n-hexadecane, 2,2'-azobisisobutyronitrile and sodium dodecyl sulfate are mixed, then transferred into deionized water, stirred for 1-2 hours for pre-emulsification, and then ultrasonically treated for 3-5 minutes to obtain a monomer microemulsion; Step 3: Add the monomer microemulsion to the pigment dispersion, stir ultrasonically for 10-20 minutes, then heat to 70-80°C, react for 12-13 hours under a protective atmosphere to obtain a pre-dispersed pigment.

2. The surface modified pre-dispersed pigment modification method according to claim 1, characterized in that: The mass ratio of the pigment dispersion to the monomer microemulsion is 4:(1-1.5).

3. The surface modified pre-dispersed pigment modification method according to claim 1, characterized in that: The pigment dispersion comprises the following components: by weight, 50-80 parts of copper phthalocyanine pigment, 5-7 parts of sodium lauryl sulfate, and 400-450 parts of deionized water; The monomer microemulsion comprises the following components: by weight, 15-18 parts of styrene, 6-8 parts of modified monomers, 0.6-0.8 parts of n-hexadecane, 0.3-0.5 parts of 2,2'-azobisisobutyronitrile, 1-2 parts of sodium dodecyl sulfate, and 100-120 parts of deionized water.

4. The surface modified pre-dispersed pigment modification method according to claim 1, characterized in that: The preparation process of the modified monomer is: S1: p-nitrobenzaldehyde, 4-bromomethyl-5H-furan-2-one, 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester and dichloromethane were mixed and stirred for 30-40 minutes, and a catalyst L-proline was added. The mixture was reacted at room temperature for 12-13 hours. After purification, the mixture was mixed with ammonium chloride, methanol, iron powder and deionized water, and ultrasonically stirred for 10-20 minutes. The mixture was heated to 80-90°C and reacted for 3-4 hours. The solvent was removed by rotary evaporation. After cooling, the mixture was filtered, washed and dried to obtain intermediate A. S2: Mix 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, ethyl chloroacetate, acetonitrile and potassium carbonate, heat to 80-90°C, react for 7-8h, cool to room temperature, add N-bromosuccinimide and p-toluenesulfonic acid, stir evenly, heat to 60-80°C, react for 15-20min, and obtain intermediate B; S3: anthranilic acid, phenyl isocyanate, acetone and triethylamine are mixed and reacted at room temperature for 1-2 hours. After purification, they are added to ethanol with intermediate B and reacted at room temperature for 4-5 hours. After filtering, washing and drying, they are transferred to a mixed solvent of methanol and dichloromethane, sodium hydroxide solution is added, and the reaction is carried out for 1-2 hours. The pH is adjusted to 3-4, and post-processed to obtain intermediate C; S4: Intermediate A, intermediate C and dimethylformamide are mixed, dicyclohexylcarbodiimide is added, the temperature is raised to 70-80° C., the reaction is performed for 4-5 hours, the mixture is cooled to room temperature, and the modified monomer is obtained by post-treatment.

5. The surface modified pre-dispersed pigment modification method according to claim 4, characterized in that: The intermediate A raw material comprises the following components: by weight, 2-3 parts of p-nitrobenzaldehyde, 0.5-1 parts of 4-bromomethyl-5H-furan-2-one, 1-2 parts of 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester, 40-50 parts of dichloromethane, 0.1-0.2 parts of L-proline, 1-2 parts of ammonium chloride, 60-70 parts of methanol, 0.3-0.5 parts of iron powder, and 10-12 parts of deionized water.

6. The surface modified pre-dispersed pigment modification method according to claim 4, characterized in that: The intermediate B raw material includes the following components: by weight, 10-12 parts of 1-[2-(allyloxy)-6-hydroxyphenyl]-1-ethanone, 8-10 parts of ethyl chloroacetate, 60-80 parts of acetonitrile, 0.1-0.2 parts of potassium carbonate, 2-3 parts of N-bromosuccinimide, and 0.1-0.2 parts of p-toluenesulfonic acid.

7. The surface modified pre-dispersed pigment modification method according to claim 4, characterized in that: The intermediate C raw material comprises the following components: by weight, 12-15 parts of anthranilic acid, 10-12 parts of phenyl isocyanate, 60-70 parts of acetone, 0.1-0.2 parts of triethylamine, 8-10 parts of intermediate B, 40-50 parts of ethanol, 8-10 parts of a mixed solvent of methanol and dichloromethane, and 4-5 parts of a sodium hydroxide solution.

8. The surface modified pre-dispersed pigment modification method according to claim 4, characterized in that: The modified monomer raw material comprises the following components: by weight, 6-8 parts of intermediate A, 10-12 parts of intermediate C, 70-80 parts of dimethylformamide, and 0.1-0.2 parts of dicyclohexylcarbodiimide.

9. The pre-dispersed pigment obtained by the surface-modified pre-dispersed pigment modification method according to any one of claims 1 to 8.

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