Preparation method of printing ink and product thereof

Abstract

The invention provides a preparation method of printing ink and a product thereof. A differentiated resin method is adopted, so that the color mixing resistance of the bottom covering ink and the color ink is improved; titanium dioxide is treated by pentaerythritol, so that the anti-settling stability of the bottom-covering ink is remarkably improved, and the spraying stability is improved; by screening and combining pigments with different hue angles, the hue angle difference delta h degree of the ink combination is reduced, and the color gamut volume is increased; through a mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, the concentration and the stability of the graphene dispersion liquid are improved, and the friction resistance and the stability of the ink are further improved; and behenic acid is adopted for treatment, so that the friction resistance of the ink is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ink, in particular to a preparation method of ink and a product thereof. BACKGROUND

[0002] In the field of inkjet printing technology, especially in industrial high-speed printing applications, the performance of ink directly determines the printing quality and reliability. Currently, water-based ink faces some technical problems that have not been completely solved when dealing with low-absorptive substrates (such as PET film, PVC, and other plastic substrates) and achieving high-precision color reproduction.

[0003] (1) Challenge of color mixing resistance: In the printing process of traditional water-based ink systems, especially when wet-on-wet overprinting is performed, different colors of ink are prone to mixed color bleeding. When the previously printed base coat (such as white ink) has not completely dried, the subsequent overprinted color ink will diffuse and mix with it, resulting in blurred pattern boundaries, color distortion, and difficulty in obtaining sharp images. This problem is particularly prominent in the process of using white ink as a base coat, and then printing color images on top of it. Although the problem can be alleviated to some extent by improving the drying process (such as substrate heating), in single-pass printing systems that pursue extremely high printing speed, the ink drying time is extremely short, and the color mixing problem remains a key factor restricting the printing quality.

[0004] (2) Problem of pigment dispersion stability and jetting reliability: To achieve high hiding power, white ink usually needs to use a high proportion of high-density titanium dioxide pigment. However, these pigment particles are prone to sedimentation and agglomeration in low-viscosity water-based systems, resulting in unstable ink dispersion systems. During printing, the settled pigments can cause nozzle clogging of the printhead, leading to jetting failure, which seriously affects the continuity of production and the service life of the printhead. Although the addition of dispersants and surfactants can maintain stability in the short term, the sedimentation problem will still cause printing defects when the printhead is restarted after a pause (such as several hours).

[0005] (3) Limitation of color gamut expansion and color accuracy: In terms of color reproduction, the traditional four-color ink system has inherent limitations in reproducing certain specific colors. For example, using a single magenta pigment cannot perfectly reproduce both bright and vivid pink and deep and rich burgundy. Optimizing the pigment for producing deep red will appear yellowish or dull when printing light pink, while optimizing the pigment for light pink cannot produce enough color intensity to represent deep red. This contradiction limits the color gamut volume of the entire ink system, especially in the red-magenta-purple region, making it difficult to meet the high requirements of professional image printing for color accuracy and richness.

[0006] (4) The problem of functional additive introduction: In recent years, in order to improve the performance of ink film (such as conductivity, anti-friction), various nanomaterials such as graphene have been added to the ink. However, how to realize the high concentration and high stability dispersion of these nanomaterials in the ink system is a big challenge. The conventional ultrasonic peeling method is inefficient, and the nanosheets obtained by peeling are easy to re-stack and difficult to store for a long time. In addition, the introduction of these nanomaterials often negatively affects the rheological properties (such as increasing the viscosity) and jetting performance of the ink. SUMMARY

[0007] In order to solve the above problems, the first aspect of the present application provides a preparation method of an ink, comprising the following steps: Step S1, polyethylene glycol grafted styrene-maleic anhydride copolymer: disperse styrene-maleic anhydride copolymer, polyethylene glycol and titanium tetraisopropoxide in butanol to carry out grafting reaction to obtain reaction liquid A; add dimethylaminoethanol to the reaction liquid A to carry out neutralization reaction to obtain reaction liquid B; add water to the reaction liquid B and distill to obtain dispersion liquid C; Step S2, pentaerythritol treatment of titanium dioxide: grind and mix titanium dioxide powder, water and pentaerythritol to carry out coordination reaction to obtain reaction liquid D; filter the reaction liquid D, collect the filter cake, and the filter cake is washed and dried to obtain titanium dioxide E; Step S3, behenic acid treatment of titanium dioxide E: grind and disperse titanium dioxide E, water and behenic acid to obtain dispersion liquid F; filter the dispersion liquid F, collect the filter cake, and the filter cake is washed and dried to obtain titanium dioxide G; grind and mix the dispersion liquid C, titanium dioxide G and water to obtain dispersion liquid H; Step S4, preparation of primer ink: disperse the dispersion liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water uniformly to obtain ink I; Step S5, polymerization reaction: disperse lauryl methacrylate, acrylic acid and 2,2'-azobis(2-methylpropanediol dimethyl) in butanol to carry out polymerization reaction to obtain reaction liquid I; add dimethylaminoethanol to the reaction liquid I to carry out neutralization reaction to obtain reaction liquid J; add water to the reaction liquid J and distill to obtain dispersion liquid K; Step S6, preparation of blue phase red pigment dispersion liquid: grind and mix the dispersion liquid K, blue phase red pigment and water to obtain dispersion liquid L; Step S7, preparation of blue phase red ink: disperse the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water uniformly to obtain ink II; Step S8, preparation of yellow phase red pigment dispersion liquid: grind and mix the dispersion liquid K, yellow phase red pigment and water to obtain dispersion liquid M; Step S9, preparing yellow phase red ink: dispersing the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water to obtain ink III; Step S10, preparing graphene dispersion liquid: dispersing natural flake graphite powder in a mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, centrifuging to collect supernatant to obtain graphene dispersion liquid N; Step S11, preparing black ink: dispersing the dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water to obtain ink IV.

[0008] As a preferred technical solution, in step S1, the mass concentration of the dispersion liquid C is 40% to 50%; the mass ratio of the styrene-maleic anhydride copolymer, polyethylene glycol, titanium tetraisopropoxide, and butanol is 100: (150 to 250): (0.5 to 1.5): (150 to 250); the grafting reaction reflux temperature is 105°C to 110°C, and the reaction time is 4h to 5h; the neutralization reaction temperature is 20°C to 30°C; the mass ratio of the reaction liquid A and dimethylaminoethanol is 100: (3 to 7); the mass ratio of the reaction liquid B and water is 100: (80 to 120); the distillation temperature is 95°C to 105°C, and the distillation time is 2h to 4h. Distillation can remove butanol.

[0009] As a preferred technical solution, in step S2, the coordination reaction temperature is 80°C to 90°C, and the time is 2h to 4h; the mass ratio of the titanium dioxide powder, water, and pentaerythritol is 100: (300 to 320): (5 to 8); the washing solution is water; the drying temperature is 100°C to 120°C, and the time is 5h to 7h; the grinding medium is 0.5mm zirconia beads.

[0010] As a preferred technical solution, in step S3, the grinding and dispersing temperature is 90°C to 100°C, and the time is 2h to 4h; the grinding medium is 0.5mm zirconia beads; the mass ratio of the titanium dioxide E, water, and behenic acid is 100: (300 to 320): (3 to 5); the washing solution is water; the drying temperature is 100°C to 120°C, and the time is 5h to 7h; the particle size of the dispersion liquid H is 180nm to 250nm; the grinding medium is 0.5mm zirconia beads; the grinding temperature is 20°C to 30°C; the mass ratio of the dispersion liquid C, titanium dioxide G, and water is 100: (300 to 350): (50 to 100).

[0011] As a preferred technical solution, in step S4, the mass ratio of the dispersion liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water is 100:(10-20):(20-40):(0.5-2):(50-100); the mass fraction of the acrylic emulsion is 35%-45%; the silicone surfactant is polyether-modified hydroxy-functional polydimethylsiloxane, which is sourced from BYK-Chemie GmbH, model BYK-345.

[0012] As a preferred technical solution, in step S5, the mass concentration of the dispersion liquid K is 40%-50%; the mass ratio of lauryl methacrylate, acrylic acid, 2,2'-azobis(2-methylpropionamide dimethyl), and butanol is 100:(15-25):(1-3):(150-250); the polymerization reaction temperature is 105°C-110°C, and the reaction time is 4h-5h; the neutralization reaction temperature is 20°C-30°C; the mass ratio of the reaction liquid I and dimethylaminoethanol is 100:(5-15); the mass ratio of the reaction liquid J and water is 100:(50-150); the distillation temperature is 95°C-105°C, and the distillation time is 2h-4h.

[0013] As a preferred technical solution, in step S6, the particle size of the dispersion liquid L is 150nm-200nm; the grinding medium is 0.5mm zirconium oxide beads; the grinding temperature is 20°C-30°C; the mass ratio of the dispersion liquid K, blue phase red pigment, and water is 100:(150-180):(500-600); the blue phase red pigment is Pigment Red 122. The blue phase red pigment is quinacridone magenta.

[0014] As a preferred technical solution, in step S7, the mass ratio of the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water is 100:(90-110):(130-140):(3-4):(200-250); the mass fraction of the acrylic emulsion is 35%-45%; the silicone surfactant is polyether-modified hydroxy-functional polydimethylsiloxane, which is sourced from BYK-Chemie GmbH, model BYK-345.

[0015] As a preferred technical solution, in step S8, the particle size of the dispersion M is 150nm-200nm; the grinding medium is 0.5mm zirconium oxide beads; the grinding temperature is 20℃-30℃; the mass ratio of the dispersion K, the yellow phase red pigment, and water is 100:(150-180):(500-600); the yellow phase red pigment is Pigment Red 209; the hue angle difference between the blue phase red pigment and the yellow phase red pigment is less than 10°; the yellow phase red pigment is naphthol AS red.

[0016] As a preferred technical solution, in step S9, the mass ratio of the dispersion M, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water is 100:(90-110):(130-140):(3-4):(330-350); the mass fraction of the acrylic emulsion is 35%-45%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345.

[0017] As a preferred technical solution, in step S10, the volume ratio of N-methyl-2-pyrrolidone and n-octylbenzene is (5-6):1; the mass ratio of graphite powder and mixed solvent is (1-2):100; the dispersion method is ultrasonic crushing, the ultrasonic crushing power is 600W, the temperature is 40℃, and the time is 6 hours; the centrifugal speed is 10000 rpm, and the centrifugal time is 30 minutes.

[0018] As a preferred technical solution, in step S11, the mass ratio of the dispersion N, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water is 100:(90-110):(130-140):(3-4):(330-350); the mass fraction of the acrylic emulsion is 35%-45%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345.

[0019] The second aspect of the present application provides an ink, which is prepared by any one of the aforementioned methods.

[0020] The third aspect of the present application provides a method for improving the color mixing resistance of an ink, which adopts the preparation method of the aforementioned ink.

[0021] The fourth aspect of the present application provides a method for improving the jetting stability of an ink, which adopts the preparation method of the aforementioned ink.

[0022] In a fifth aspect, the present application provides a method for improving the color gamut volume of ink, which uses the above-mentioned method for preparing ink.

[0023] In a sixth aspect, the present application provides a method for improving the anti-friction performance of ink, which uses the above-mentioned method for preparing ink.

[0024] Through the above technical solutions, the present application has the following technical effects: (1) The method of using different resins improves the anti-color mixing performance of the base ink and the color ink.

[0025] (2) By treating titanium dioxide with pentaerythritol, the anti-settling stability of the base ink is significantly improved, and the jetting stability is improved.

[0026] (3) By selecting and combining pigments with different hue angles, the hue angle difference |Δh°| of the ink combination is reduced, and the color gamut volume is improved.

[0027] (4) By using the mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, the concentration, stability and single-layer graphene yield of the graphene dispersion liquid are improved, and the anti-friction performance and stability of the ink are improved.

[0028] (5) By accurately controlling the resistivity of the ink, the ink is vaporized into bubbles by Joule effect, and the ink droplets are driven to be jetted.

[0029] (6) The anti-friction performance of the ink is improved by using behenic acid treatment. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the applicant explains and analyzes through specific comparative examples and examples.

[0031] Example 1

[0032] Step S1, polyethylene glycol grafted styrene-maleic anhydride copolymer: disperse styrene-maleic anhydride copolymer, polyethylene glycol and titanium isopropylate in butanol to carry out grafting reaction to obtain reaction liquid A; add dimethylaminoethanol to the reaction liquid A to carry out neutralization reaction to obtain reaction liquid B; add water to the reaction liquid B and distill to obtain dispersion liquid C; the mass concentration of the dispersion liquid C is 50%; The mass ratio of the styrene-maleic anhydride copolymer, polyethylene glycol, titanium isopropylate and butanol is 100:150:0.5:150; the reflux temperature of the grafting reaction is 110°C, and the reaction time is 5h; the neutralization reaction temperature is 30°C; the mass ratio of the reaction liquid A and dimethylaminoethanol is 100:3; the mass ratio of the reaction liquid B and water is 100:80; the distillation temperature is 105°C, and the distillation time is 4h; Step S2, pentaerythritol treatment of titanium dioxide: titanium dioxide powder, water, pentaerythritol are mixed by grinding to carry out coordination reaction to obtain reaction liquid D; the reaction liquid D is filtered, and the filter cake is collected; the filter cake is washed and dried to obtain titanium dioxide E; the coordination reaction temperature is 90℃, and the time is 4h; the mass ratio of the titanium dioxide powder, water, pentaerythritol is 100:300:5; the washing solution is water; the drying temperature is 120℃, and the time is 7h; the grinding medium is 0.5mm zirconium oxide beads; Step S3, behenic acid treatment of titanium dioxide E: titanium dioxide E, water, behenic acid are dispersed by grinding to obtain dispersion liquid F; the dispersion liquid F is filtered, and the filter cake is collected; the filter cake is washed and dried to obtain titanium dioxide G; the grinding and dispersing temperature is 100℃, and the time is 4h; the grinding medium is 0.5mm zirconium oxide beads; the mass ratio of the titanium dioxide E, water, behenic acid is 100:300:3; the washing solution is water; the drying temperature is 120℃, and the time is 7h; The dispersion liquid C, titanium dioxide G, water are mixed by grinding to obtain dispersion liquid H; the particle size of the dispersion liquid H is 250nm; the grinding medium is 0.5mm zirconium oxide beads; the grinding temperature is 30℃; the mass ratio of the dispersion liquid C, titanium dioxide G, water is 100:300:50; Step S4, preparation of base hiding ink: the dispersion liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water are uniformly dispersed to obtain ink I; the mass ratio of the dispersion liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water is 100:10:20:0.5:50; the mass fraction of the acrylic emulsion is 45%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S5, polymerization reaction: lauryl methacrylate, acrylic acid, 2,2'-azobis(2-methylpropanediol dimethyl) are dispersed in butanol to carry out polymerization reaction to obtain reaction liquid I; dimethylaminoethanol is added to the reaction liquid I to carry out neutralization reaction to obtain reaction liquid J; water is added to the reaction liquid J to obtain dispersion liquid K by distillation; the mass concentration of the dispersion liquid K is 50%; The mass ratio of the lauryl methacrylate, acrylic acid, 2,2'-azobis(2-methylpropanediol dimethyl), butanol is 100:15:1:150; the polymerization reaction temperature is 110℃, and the reaction time is 5h; the neutralization reaction temperature is 30℃; the mass ratio of the reaction liquid I and dimethylaminoethanol is 100:5; the mass ratio of the reaction liquid J and water is 100:50; the distillation temperature is 105℃, and the distillation time is 4h; Step S6, preparing a blue phase red pigment dispersion liquid: dispersing the dispersion liquid K, the blue phase red pigment and water to obtain a dispersion liquid L; the particle size of the dispersion liquid L is 200 nm; the grinding medium is 0.5 mm zirconium oxide beads; the grinding temperature is 30℃; the mass ratio of the dispersion liquid K, the blue phase red pigment and water is 100:150:500; the blue phase red pigment is Pigment Red 122; Step S7, preparing a blue phase red ink: uniformly dispersing the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water to obtain an ink II; the mass ratio of the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water is 100:90:130:3:200; the mass fraction of the acrylic emulsion is 45%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S8, preparing a yellow phase red pigment dispersion liquid: dispersing the dispersion liquid K, the yellow phase red pigment and water to obtain a dispersion liquid M; the particle size of the dispersion liquid M is 200 nm; the grinding medium is 0.5 mm zirconium oxide beads; the grinding temperature is 30℃; the mass ratio of the dispersion liquid K, the yellow phase red pigment and water is 100:150:500; the yellow phase red pigment is Pigment Red 209; Step S9, preparing a yellow phase red ink: uniformly dispersing the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water to obtain an ink III; the mass ratio of the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water is 100:90:130:3:330; the mass fraction of the acrylic emulsion is 45%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S10, preparing a graphene dispersion liquid: dispersing natural flake graphite powder in a mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, and centrifuging to collect the supernatant to obtain a graphene dispersion liquid N; the volume ratio of N-methyl-2-pyrrolidone and n-octylbenzene is 5:1; the mass ratio of graphite powder to mixed solvent is 1:100; the dispersion method is ultrasonic crushing, the ultrasonic crushing power is 600 W, the temperature is 40℃, and the time is 6 hours; the centrifugal speed is 10000 rpm, and the centrifugal time is 30 minutes; Step S11, preparing black ink: dispersing the dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water to obtain ink IV; the mass ratio of the dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water is 100:90:130:3:330; the mass fraction of the acrylic emulsion is 45%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model number BYK-345.

[0033] Example 2

[0034] Step S1, grafting styrene-maleic anhydride copolymer with polyethylene glycol: dispersing styrene-maleic anhydride copolymer, polyethylene glycol and tetraisopropyl titanate in butanol to carry out grafting reaction to obtain reaction liquid A; adding dimethylaminoethanol to reaction liquid A to carry out neutralization reaction to obtain reaction liquid B; adding water to reaction liquid B to obtain dispersion liquid C through distillation; the mass concentration of the dispersion liquid C is 45%; the mass ratio of the styrene-maleic anhydride copolymer, polyethylene glycol, tetraisopropyl titanate and butanol is 100:200:1:200; the reflux temperature of the grafting reaction is 106℃, and the reaction time is 4.5h; the neutralization reaction temperature is 25℃; the mass ratio of the reaction liquid A and dimethylaminoethanol is 100:5; the mass ratio of the reaction liquid B and water is 100:100; the distillation temperature is 100℃, and the distillation time is 3h; Step S2, treating titanium dioxide with pentaerythritol: grinding and mixing titanium dioxide powder, water and pentaerythritol to carry out coordination reaction to obtain reaction liquid D; filtering reaction liquid D to collect filter cake, which is washed and dried to obtain titanium dioxide E; the coordination reaction temperature is 85℃, and the time is 3h; the mass ratio of the titanium dioxide powder, water and pentaerythritol is 100:310:7; the washing solution is water; the drying temperature is 110℃, and the time is 6h; the grinding medium is 0.5mm zirconium oxide beads; Step S3, treating titanium dioxide E with behenic acid: grinding and dispersing titanium dioxide E, water and behenic acid to obtain dispersion liquid F; filtering dispersion liquid F to collect filter cake, which is washed and dried to obtain titanium dioxide G; the grinding and dispersing temperature is 95℃, and the time is 3h; the grinding medium is 0.5mm zirconium oxide beads; the mass ratio of the titanium dioxide E, water and behenic acid is 100:310:4; the washing solution is water; the drying temperature is 110℃, and the time is 6h; Disperse liquid C, titanium dioxide G, water are ground to obtain dispersion liquid H; the particle size of the dispersion liquid H is 200 nm; the grinding medium is 0.5 mm zirconium oxide beads; the grinding temperature is 25℃; the mass ratio of the dispersion liquid C, titanium dioxide G, water is 100:320:80; Step S4, base hiding ink preparation: disperse liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water uniformly to obtain ink I; the mass ratio of the disperse liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water is 100:15:30:1:70; the mass fraction of the acrylic emulsion is 40%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S5, polymerization reaction: disperse lauryl methacrylate, acrylic acid, 2,2'-azobis(2-methylpropanoic acid dimethyl ester) in butanol to carry out polymerization reaction to obtain reaction liquid I; add dimethylaminoethanol to the reaction liquid I to carry out neutralization reaction to obtain reaction liquid J; add water to the reaction liquid J to obtain dispersion liquid K through distillation; the mass concentration of the dispersion liquid K is 45%; The mass ratio of the lauryl methacrylate, acrylic acid, 2,2'-azobis(2-methylpropanoic acid dimethyl ester), butanol is 100:20:2:200; the polymerization reaction temperature is 108℃, and the reaction time is 4.5 h; the neutralization reaction temperature is 25℃; the mass ratio of the reaction liquid I and dimethylaminoethanol is 100:10; the mass ratio of the reaction liquid J and water is 100:100; the distillation temperature is 100℃, and the distillation time is 3 h; Step S6, preparation of blue phase red pigment dispersion liquid: grind and mix the dispersion liquid K, blue phase red pigment, water to obtain dispersion liquid L; the particle size of the dispersion liquid L is 170 nm; the grinding medium is 0.5 mm zirconium oxide beads; the grinding temperature is 25℃; the mass ratio of the dispersion liquid K, blue phase red pigment, water is 100:160:550; the blue phase red pigment is Pigment Red 122; Step S7, preparation of blue phase red ink: disperse the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water uniformly to obtain ink II; the mass ratio of the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water is 100:100:135:3.5:220; the mass fraction of the acrylic emulsion is 40%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S8, preparing yellow phase red pigment dispersion liquid: dispersing liquid K, yellow phase red pigment, water to obtain dispersion liquid M; the particle size of the dispersion liquid M is 180 nm; the grinding medium is 0.5 mm zirconium oxide beads; the grinding temperature is 25℃; the mass ratio of the dispersion liquid K, yellow phase red pigment, water is 100:160:550; the yellow phase red pigment is Pigment Red 209; Step S9, preparing yellow phase red ink: dispersing the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water to obtain ink III; the mass ratio of the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water is 100:100:135:3.5:340; the mass fraction of the acrylic emulsion is 40%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S10, preparing graphene dispersion liquid: dispersing natural flake graphite powder in a mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, centrifuging to collect the supernatant to obtain graphene dispersion liquid N; the volume ratio of N-methyl-2-pyrrolidone and n-octylbenzene is 5.5:1; the mass ratio of graphite powder to mixed solvent is 1.5:100; the dispersion method is ultrasonic crushing, the ultrasonic crushing power is 600W, the temperature is 40℃, and the time is 6 hours; the centrifugal speed is 10000 rpm, and the centrifugal time is 30 minutes; Step S11, preparing black ink: dispersing the dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water to obtain ink IV; the mass ratio of the dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant, water is 100:100:135:3.5:340; the mass fraction of the acrylic emulsion is 40%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345.

[0035] Example 3

[0036] Step S1, polyethylene glycol grafting styrene-maleic anhydride copolymer: dispersing styrene-maleic anhydride copolymer, polyethylene glycol, titanium tetraisopropoxide in butanol to carry out grafting reaction to obtain reaction liquid A; adding dimethylaminoethanol to reaction liquid A to carry out neutralization reaction to obtain reaction liquid B; adding water to reaction liquid B and distilling to obtain dispersion liquid C; the mass concentration of the dispersion liquid C is 40%; The mass ratio of the styrene-maleic anhydride copolymer, polyethylene glycol, titanium tetraisopropoxide and butanol is 100:250:1.5:250; the grafting reaction reflux temperature is 105℃, and the reaction time is 4h; the neutralization reaction temperature is 20℃; the mass ratio of the reaction liquid A and dimethylaminoethanol is 100:7; the mass ratio of the reaction liquid B and water is 100:120; the distillation temperature is 95℃, and the distillation time is 2h; Step S2, pentaerythritol treatment of titanium dioxide: grinding and mixing titanium dioxide powder, water and pentaerythritol to carry out coordination reaction to obtain reaction liquid D; filtering the reaction liquid D, collecting the filter cake, and washing and drying the filter cake to obtain titanium dioxide E; the coordination reaction temperature is 80℃, and the time is 2h; the mass ratio of the titanium dioxide powder, water and pentaerythritol is 100:320:8; the washing solution is water; the drying temperature is 100℃, and the time is 5h; the grinding medium is 0.5mm zirconium oxide beads; Step S3, behenic acid treatment of titanium dioxide E: grinding and dispersing titanium dioxide E, water and behenic acid to obtain dispersion liquid F; filtering the dispersion liquid F, collecting the filter cake, and washing and drying the filter cake to obtain titanium dioxide G; the grinding and dispersing temperature is 90℃, and the time is 2h; the grinding medium is 0.5mm zirconium oxide beads; the mass ratio of the titanium dioxide E, water and behenic acid is 100:320:5; the washing solution is water; the drying temperature is 100℃, and the time is 5h; Grinding and mixing the dispersion liquid C, titanium dioxide G and water to obtain dispersion liquid H; the particle size of the dispersion liquid H is 180nm; the grinding medium is 0.5mm zirconium oxide beads; the grinding temperature is 20℃; the mass ratio of the dispersion liquid C, titanium dioxide G and water is 100:350:100; Step S4, preparation of base hiding ink: uniformly dispersing the dispersion liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water to obtain ink I; the mass ratio of the dispersion liquid H, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water is 100:20:40:2:100; the mass fraction of the acrylic emulsion is 35%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S5, polymerization reaction: dispersing lauryl methacrylate, acrylic acid and 2,2'-azobis(2-methylpropanediol dimethyl) in butanol to carry out polymerization reaction to obtain reaction liquid I; adding dimethylaminoethanol to the reaction liquid I to carry out neutralization reaction to obtain reaction liquid J; adding water to the reaction liquid J to obtain dispersion liquid K by distillation; the mass concentration of the dispersion liquid K is 40%; The mass ratio of the lauryl methacrylate, the acrylic acid, 2,2'-azobis(2-methylpropanediol dimethyl ester), butanol is 100:25:3:250; the polymerization reaction temperature is 105℃, and the reaction time is 4h; the neutralization reaction temperature is 20℃; the mass ratio of the reaction liquid I and dimethylaminoethanol is 100:15; the mass ratio of the reaction liquid J and water is 100:150; the distillation temperature is 95℃, and the distillation time is 2h; Step S6, preparing a blue phase red pigment dispersion liquid: grinding and mixing the dispersion liquid K, the blue phase red pigment, and water to obtain a dispersion liquid L; the particle size of the dispersion liquid L is 150nm; the grinding medium is 0.5mm zirconium oxide beads; the grinding temperature is 20℃; the mass ratio of the dispersion liquid K, the blue phase red pigment, and water is 100:180:600; the blue phase red pigment is Pigment Red 122; Step S7, preparing a blue phase red ink: uniformly dispersing the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water to obtain ink II; the mass ratio of the dispersion liquid L, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water is 100:110:140:4:250; the mass fraction of the acrylic emulsion is 35%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S8, preparing a yellow phase red pigment dispersion liquid: grinding and mixing the dispersion liquid K, the yellow phase red pigment, and water to obtain a dispersion liquid M; the particle size of the dispersion liquid M is 150nm; the grinding medium is 0.5mm zirconium oxide beads; the grinding temperature is 20℃; the mass ratio of the dispersion liquid K, the yellow phase red pigment, and water is 100:180:600; the yellow phase red pigment is Pigment Red 209; Step S9, preparing a yellow phase red ink: uniformly dispersing the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water to obtain ink III; the mass ratio of the dispersion liquid M, 1,2-hexanediol, acrylic emulsion, silicone surfactant, and water is 100:110:140:4:350; the mass fraction of the acrylic emulsion is 35%; the silicone surfactant is polyether modified hydroxyl functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345; Step S10, preparing graphene dispersion liquid: dispersing natural flake graphite powder in a mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, collecting supernatant by centrifugation to obtain graphene dispersion liquid N; the volume ratio of N-methyl-2-pyrrolidone and n-octylbenzene is 6:1; the mass ratio of graphite powder and mixed solvent is 2:100; the dispersion method is ultrasonic crushing, the ultrasonic crushing power is 600 W, the temperature is 40°C, and the time is 6 hours; the centrifugal speed is 10000 rpm, and the centrifugal time is 30 minutes; Step S11, preparing black ink: uniformly dispersing dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water to obtain ink IV; the mass ratio of dispersion liquid N, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water is 100:110:140:4:350; the mass fraction of the acrylic emulsion is 35%; the silicone surfactant is polyether modified hydroxy functional polydimethylsiloxane, which is from BYK-Chemie GmbH, model BYK-345.

[0037] Comparative Example 1

[0038] In step S6, step S8, dispersion liquid C is used instead of dispersion liquid K, that is, ink I, ink II and ink III are all prepared using dispersion liquid C. Other steps and parameters are consistent with example 1.

[0039] Comparative Example 2

[0040] In step S3, dispersion liquid K is used instead of dispersion liquid C, that is, ink I, ink II and ink III are all prepared using dispersion liquid K. Other steps and parameters are consistent with example 1.

[0041] Test Example 1, anti-color mixing effect evaluation method: 1. Test method Print on low-absorbing substrate (PET film) and heat the substrate (40-80°C). First print a layer of base ink (white) to cover the entire area. When the base ink (ink I) is not completely dry, immediately print another ink (ink II and ink III) fine pattern (5pt text) on top. The printing speed is set to 10 m² / h, 8 m² / h, 6 m² / h, 4 m² / h respectively.

[0042] This test method simulates the industrial printing environment and creates the most likely conditions for color mixing: wet-on-wet printing, non-absorbing substrate (ink cannot penetrate, only flows horizontally), high-speed printing (very short drying time).

[0043] 2. Evaluation criteria

[0044] The print samples were examined by the evaluator with a magnifying glass. The quantitative grading criteria were as follows: A+: No color mixing phenomenon was observed at the very high printing speed of 10 m2 / h.

[0045] A: No color mixing at the speed of 8 m2 / h.

[0046] B: No color mixing at the speed of 6 m2 / h.

[0047] C: No color mixing at the speed of 4 m2 / h.

[0048] D: Color mixing was still observed at the speed of 4 m2 / h.

[0049] 3. Test results

[0050] The test results are shown in the table below. The use of different resins for the base ink and the color ink improves the color mixing resistance.

[0051] The color ink uses a resin containing long alkyl chains to provide hydrophobicity; the base white ink uses a resin of polyethylene glycol grafted styrene-maleic anhydride copolymer to provide hydrophilicity and flexibility. The PEG segments on the grafts act like hydrated "hairs" to provide strong steric stabilization and hydrophilic surfaces to the resin. Due to the huge chemical difference between the two resins, even when the two inks are in the state of overprinting before complete drying, the dispersed resin repels each other, effectively preventing the migration and mixing of pigment particles, and suppressing the color mixing phenomenon.

[0052] Table 1: Evaluation results of color mixing resistance

[0053] Comparative Example 3

[0054] Titanium dioxide without pentaerythritol treatment in step S2, i.e. in step S3, using ordinary titanium dioxide instead of pentaerythritol-treated titanium dioxide, and other steps and parameters being the same as in Example 1.

[0055] Test Example 2, evaluation of sedimentation resistance and jetting stability: Evaluation method of sedimentation resistance and jetting stability: Fill the ink (Ink I) into the print head (use Kyocera KJ4A nozzle, and use 200 nozzles at the same time), confirm that all nozzles are normally jetted, and then let the device stand for 2 hours without protection (without cap). Then test the nozzles again, and count the percentage of blocked nozzles.

[0056] The test results are shown in the following table. The treatment of titanium dioxide with pentaerythritol can significantly improve the anti-settling stability of the undercoat ink and improve the jetting stability. Pentaerythritol is a four-membered alcohol, and its molecular structure is symmetrical and contains four equivalent primary hydroxyl groups. The surface of titanium dioxide is rich in hydrated hydroxyl groups (Ti-OH), which are amphoteric and can act as both an acid and a base, allowing them to strongly complex with the hydroxyl groups of polyols. Under heating conditions, one or more hydroxyl groups (-OH) in the pentaerythritol molecule will lose a proton (H+) ), and the titanium atoms on the surface of TiO2 can provide empty orbitals to accept lone pair electrons from the hydroxyl groups of pentaerythritol, thereby forming coordinate bonds. This reaction is not simply physical adsorption, but rather tends to form a chemical anchor. This chemical force is much stronger than physical adsorption, allowing the pentaerythritol molecules to be stably coated on the surface of the pigment and not easily detached during subsequent processing or storage, thereby providing long-term dispersion stability. The abundant hydroxyl groups of pentaerythritol will also form a wide network of hydrogen bonds with the Ti-OH groups on the surface of TiO2. Although this force is weaker than the coordinate bond, the number is large, which is crucial for the initial adsorption and approach, and creates conditions for subsequent stronger chemical bonding. The improvement of anti-settling performance reduces the proportion of nozzle blockage and improves the jetting stability.

[0057] Table 2: Evaluation results of ink I jetting stability

[0058] Comparative Example 4

[0059] In step S8, step S9, Pigment Red 122 pigment is used instead of Pigment Red 209 pigment, that is, Pigment Red 122 pigment is used in steps S6-S9, and other steps and parameters are consistent with Example 1.

[0060] Comparative Example 5

[0061] In step S6, step S7, Pigment Red 209 pigment is used instead of Pigment Red 122 pigment, that is, Pigment Red 209 pigment is used in steps S5-S8, and other steps and parameters are consistent with Example 1.

[0062] In test example 3, the hue angle (h°) of ink II and ink III was measured respectively.

[0063] 1. Printing device

[0064] Using a 3M™ Printer 2500UV inkjet printer, create a 100% dot gain color patch file in RIP software 3M™ Scotchprint® Graphic Maker. Print the color patch on a 3M™ Controltac™ Plus IJ180C-10 vinyl standard substrate, area 2 cm x 2 cm.

[0065] 2. Specific measurement method and procedure

[0066] Use an X-Rite 528 Spectrodensitometer spectrophotometer.

[0067] Select light source D50 (simulated daylight), field of view 2°, measurement mode SCI (specular included) mode.

[0068] Place the instrument measurement port close and perpendicular to the surface of the printed color patch, trigger the measurement, and record the displayed L, a, b values after the instrument readings are stable. Measure at least 3 times at different locations on the same color patch and take the average.

[0069] 3. Data processing

[0070] After obtaining the average a and b values, calculate the hue angle: h° = arctan(b / a).

[0071] Test Example 4, Color Gamut Volume Measurement Method: 1. Print Standard Color Target Use a professional RIP (Raster Image Processor) software (3M™ Scotchprint® Graphic Maker Software). Print the standard color target file. The color target file contains color patches made of C, Y, K, W, (Ink II), (Ink III) combined in different proportions. Print the color target file through the designated inkjet printer (3M™ Printer 2500UV) on the standard substrate (3M™ Controltac™ Plus IJ180C-10 vinyl). Keep the printing conditions completely consistent to ensure the comparability of the results.

[0072] 2. Color Measurement

[0073] Use a professional spectrophotometer (X-Rite 528 Spectrodensitometer). Measure the CIE Lab values of each printed color patch under standard light source (D50), generating a measurement file containing all the Lab data of the color patches.

[0074] 3. Calculate the Gamut Volume (G)

[0075] Using professional color analysis software (Gamut Works by Monaco), the measurement file obtained in the previous step is imported into the software. The software connects all the measured color points in the CIE Lab color space to form a closed, irregular polyhedron. The volume of the space enclosed by the polyhedron is the Gamut Volume (G). Based on the Delaunay triangulation and convex hull algorithm, the discrete point cloud is converted into a three-dimensional volume. The volume unit is cubic CIELAB unit, expressed as (ΔE)³.

[0076] The test results are shown in the table below. By screening different hue angle pigments and reducing the hue angle difference |Δh°| of the ink combination, the Gamut Volume is improved.

[0077] The combination of Ink II (blue phase red pigment) and Ink III (yellow phase red pigment) can significantly improve the Gamut Volume. By using two different pigments with complementary hue characteristics, different areas in the color space are optimized, thus achieving a color range that cannot be achieved by a single pigment. Specifically, Ink II (PR122) has a smaller hue angle and performs well in the low-lightness high-saturation area (deep red, magenta), which can expand the coverage of the color space in the fourth quadrant of the a-b quadrant, producing purer and deeper red and magenta. Ink III (PR209) has a larger hue angle (e.g. about +5°) and performs well in the high-lightness low-saturation area (bright pink, light red), which can expand the coverage of the color space in the first quadrant, producing brighter and more vibrant pink. When these two inks are integrated into the same ink set and driven by a professional color management engine, the system can intelligently select or mix these two inks according to the needs of the target color. This means that when deep red needs to be reproduced, Ink II can be used mainly; when bright pink needs to be reproduced, Ink III can be used mainly; and for intermediate tones between the two, different proportions of mixing can be used to achieve the most saturated and vibrant effect. This "division of labor" strategy collectively broadens the entire color boundary of the red region, ultimately making the color range (i.e. Gamut Volume) that the entire ink system can present larger than that of an ink using a single pigment.

[0078] Table 3: Hue angle, Gamut Volume measurement results

[0079] Comparative Example 6

[0080] In step S10, N-methyl-2-pyrrolidone is used instead of the mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene; other steps and parameters are consistent with Example 1.

[0081] Comparative Example 7

[0082] Step S10, using n-octylbenzene instead of N-methyl-2-pyrrolidone and n-octylbenzene mixed solvent; other steps and parameters are consistent with example 1.

[0083] Detection example 5, graphene concentration measurement method: 1. Separate the unexfoliated graphite and stably dispersed graphene by high-speed centrifugation (10000 rpm, 30 minutes); 2. The graphene concentration in the dispersion is determined by the filtration-weighing method, and the specific method is as follows: Accurately take the uniform graphene dispersion after centrifugal purification, the volume is (V mL). The mass of a dry PTFE (polytetrafluoroethylene) filter membrane with a specific pore size (100 nm) is weighed (5 times) (M g), and the average value is recorded. ),

[0084] Place the sample in a vacuum filtration device for filtration. Use chloroform and diethyl ether to wash thoroughly to remove the stabilizer molecules and residual original solvent adsorbed on the surface of graphene.

[0085] Dry the filter membrane with sediment in an oven to remove the washing solvent.

[0086] Weigh the total mass of "filter membrane + graphene" after drying (M g), and record the average value (5 times). ),

[0087] The graphene concentration (C) is calculated by the following formula: C (μg / mL) = [ (M - M0) (μg) ] / [V (mL) ] -

[0088] Detection example 6, determine the anti-friction performance of ink IV according to GB / T 7706-2008.

[0089] The test results are shown in the table below. The mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene can improve the concentration, stability and single-layer graphene yield of the graphene dispersion, and further improve the anti-friction performance and stability of the ink.

[0090] The n-octylbenzene molecule quickly inserts between the torn graphite layers and adsorbs on the newly generated graphene surface due to the strong π-π interaction between its benzene ring and the graphene basal plane, and the extended octyl long chain produces steric hindrance, effectively preventing the re-stacking of graphene sheets, improving the stability and concentration of the dispersion. After centrifugation, the large particles that have not been exfoliated or re-aggregated are removed by sedimentation, and the supernatant is a uniform dispersion. The ability to withstand high-speed centrifugation without large-scale sedimentation or stratification is direct evidence of the good kinetic stability of the dispersion.​

[0091] The uniformly distributed graphene sheets as nano-reinforced phase can effectively hinder the propagation of micro-cracks - the cracks will deflect, branch and pin when encountering high-strength graphene sheets, consume energy, thereby delaying the wear and damage of the material; at the same time, the extremely high mechanical strength and hardness of graphene directly bear part of the friction load, reducing the direct damage of friction to the relatively soft resin matrix, which macroscopically shows the improvement of the anti-friction performance of the ink film.

[0092] Table 4: Graphene concentration and anti-friction performance measurement results

[0093] Example 4

[0094] The ink resistivity is adjusted to 0.001 Ω·m using deionized water or sodium chloride; other steps and parameters are consistent with Example 1.

[0095] Example 5

[0096] The ink resistivity is adjusted to 0.01 Ω·m using deionized water or sodium chloride; other steps and parameters are consistent with Example 1.

[0097] Comparative Example 8

[0098] The ink resistivity is adjusted to 0.0001 Ω·m using deionized water or sodium chloride; other steps and parameters are consistent with Example 1.

[0099] Comparative Example 9

[0100] The ink resistivity is adjusted to 0.1 Ω·m using deionized water or sodium chloride; other steps and parameters are consistent with Example 1.

[0101] In Example 7, the inkjet printing test method is as follows: An electrode is arranged at the bottom of the ink chamber (first electrode) and the side wall (second electrode), respectively, a voltage is applied to the ink, the working voltage is set to 50V, the pulse is 5 microseconds, the ink itself is instantaneously heated and vaporized by using the Joule effect, generating steam bubbles, the pressure of the expanding bubbles can drive the ink droplets to be ejected. Instead of the heating resistance of the traditional thermal bubble printing head to heat the ink.

[0102] An ink droplet observation instrument is used to evaluate the flight characteristics of the ejected ink droplets.

[0103] The test results are shown in the following table. By precisely regulating the ink resistivity, it can pass a large enough current at a safe low voltage, so as to use the Joule effect to make the ink itself heat up instantly, generate steam bubbles, and the pressure of the expanding bubbles can drive the ink droplets to be ejected. After ejection, the negative pressure generated by the collapse of the bubbles replenishes new ink by capillary force, completing a spray cycle. The whole process does not require mechanical moving parts and heating components, and is efficient and long-lasting. If the resistivity is too high, a very high voltage is required to drive enough current to produce heat, which is not economical and not safe. If the resistivity is too low, the current is too large, the heat is dispersed and the circuit may be damaged.

[0104] Table 5: Inkjet printing test results

[0105] Example 6

[0106] In step S3, behenic acid is used instead of stearic acid to treat titanium dioxide E; other steps and parameters are consistent with example 1.

[0107] Comparative example 10

[0108] Titanium dioxide E treated with behenic acid without step S3, i.e. directly using titanium dioxide E to prepare dispersion liquid H; other steps and parameters are consistent with example 1.

[0109] In test example 8, the ink abrasion resistance was measured according to GB / T 7706-2008.

[0110] The test results are shown in the following table. Behenic acid treatment can significantly improve the abrasion resistance of the ink. Behenic acid is a long-chain saturated fatty acid, which can quickly cool and form a solid film layer after being sprayed onto the medium surface in a high-temperature molten state while dissolving and evaporating. Its high solidification point and molecular rigidity significantly enhance the wear resistance of the ink film. The melting point of behenic acid is significantly higher than that of stearic acid, and the ink film composed of behenic acid has higher hardness and stronger mechanical strength at room temperature. When the ink droplets impact the printing substrate, they quickly solidify, and the crystalline structure formed by behenic acid molecules is more dense and stable, and the long carbon chain provides stronger intermolecular forces, effectively resisting the destruction of external friction and preventing the printed content from being easily scratched or blurred.

[0111] In addition, compared with stearic acid, behenic acid has a longer carbon chain, higher molecular weight, higher boiling point / decomposition temperature, and higher thermal stability, which can improve the thermal stability of the ink.

[0112] Table 6: Measurement results of abrasion resistance of behenic acid treatment

Claims

1. A method for preparing an ink, characterized in that, Includes the following steps: Step S1, Polyethylene glycol grafted styrene-maleic anhydride copolymer: Styrene-maleic anhydride copolymer, polyethylene glycol, and tetraisopropyl titanate are dispersed in butanol and grafted to obtain reaction solution A; dimethylaminoethanol is added to reaction solution A for neutralization reaction to obtain reaction solution B; water is added to reaction solution B and distilled to obtain dispersion C; Step S2, Pentaerythritol treatment of titanium dioxide: Titanium dioxide powder, water and pentaerythritol are ground and mixed, and a coordination reaction is carried out to obtain reaction solution D; reaction solution D is filtered, filter cake is collected, and the filter cake is washed and dried to obtain titanium dioxide E; Step S3, behenic acid treatment of titanium dioxide E: Titanium dioxide E, water and behenic acid are ground and dispersed to obtain dispersion F; dispersion F is filtered, filter cake is collected, and the filter cake is washed and dried to obtain titanium dioxide G; dispersion C, titanium dioxide G and water are ground and mixed to obtain dispersion H; Step S4, Preparation of masking ink: Dispersion H, 1,2-hexanediol, acrylic emulsion, silicone surfactant and water are dispersed evenly to obtain ink I; Step S5, Polymerization reaction: Lauryl methacrylate, acrylic acid, and 2,2'-azobis(2-methylpropionate) are dispersed in butanol and polymerized to obtain reaction solution I; dimethylaminoethanol is added to reaction solution I for neutralization reaction to obtain reaction solution J; water is added to reaction solution J and distilled to obtain dispersion K; Step S6, prepare blue-red pigment dispersion: grind and mix dispersion K, blue-red pigment, and water to obtain dispersion L; Step S7, prepare blue-red ink: Disperse dispersion L, 1,2-hexanediol, acrylic emulsion, organosilicon surfactant and water evenly to obtain ink II; Step S8, prepare yellow-red pigment dispersion: grind and mix dispersion K, yellow-red pigment, and water to obtain dispersion M; Step S9, prepare yellow-red ink: Dispersion M, 1,2-hexanediol, acrylic emulsion, organosilicon surfactant and water are evenly dispersed to obtain ink III; Step S10, preparing graphene dispersion: Disperse natural flake graphite powder in a mixed solvent of N-methyl-2-pyrrolidone and n-octylbenzene, collect the supernatant by centrifugation, and obtain graphene dispersion N; Step S11, prepare black ink: Dispersion liquid N, 1,2-hexanediol, acrylic emulsion, organosilicon surfactant and water are dispersed evenly to obtain ink IV.

2. An ink, characterized in that, The ink is prepared by the preparation method described in claim 1.

3. A method for improving the color mixing resistance of ink, characterized in that, The method described herein employs the preparation method as described in claim 1.

4. A method for improving ink jetting stability, characterized in that, The method described herein employs the preparation method as described in claim 1.

5. A method for improving the color gamut volume of ink, characterized in that, The method described herein employs the preparation method as described in claim 1.

6. A method for improving the anti-friction properties of ink, characterized in that, The method described herein employs the preparation method as described in claim 1.

Images