Preparation method and application of water-based fine dot ink

Abstract

The present invention belongs to the technical field of water-based ink, and specifically relates to a preparation method and application of a water-based fine dot ink. The preparation method comprises: (1) filling a filler in a reaction tube, introducing HF gas and water vapor for modification treatment to obtain a modified filler; (2) preparing 15-35wt% of water-based acrylic resin, 8-20wt% of pigment, 10-30wt% of modified filler, 10-25wt% of cosolvent, 1-5wt% of polyethylene wax, 0.05-0.15wt% of neutralizer, and water supplemented to 100wt% for standby use; (3) mixing and dispersing water-based acrylic resin, modified filler, cosolvent, polyethylene wax, neutralizer and water, and grinding to a fineness of less than 15μm. The water-based ink of the present invention has excellent ink transfer, glossiness and water resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based inks, and in particular relates to a preparation method of a water-based fine dot ink and application thereof. Background Art

[0002] Water-based ink does not contain toxic and harmful organic solvents, and will not cause harm to the health of production personnel and the surrounding environment. It has excellent environmental protection. Among them, the main component of water-based ink is connecting resin, such as water-based acrylic resin. The ink containing water-based acrylic resin is acrylic ester water-based ink, and its main components are acrylic resin, pigment and water. It not only has the advantages of environmental protection, health and safety of water-based ink, but also has good adhesion and fluidity. It is suitable for printing on the surface of various non-absorbent materials and has good fluidity and adhesion. However, compared with oil-based ink, it has the problem of poor gloss, which limits its application. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem that acrylic ester water-based ink in the prior art has poor gloss and cannot balance initial drying and gloss well, and to provide a preparation method and application of water-based fine dot ink. The ink has a good balance of initial drying and gloss.

[0004] A first aspect of the present invention provides a method for preparing a water-based fine dot ink, the method comprising:

[0005] (1) loading a filler into a reaction tube, introducing HF gas and water vapor to perform a modification treatment to obtain a modified filler;

[0006] (2) preparing 15-35wt% of water-based acrylic resin, 8-20wt% of pigment, 10-30wt% of modified filler, 10-25wt% of cosolvent, 1-5wt% of polyethylene wax, 0.05-0.15wt% of neutralizer, and water to 100wt% for standby use;

[0007] (3) The water-based acrylic resin, the modified filler, the cosolvent, the polyethylene wax, the neutralizer and water are mixed and dispersed, and then ground to a fineness of less than 15 μm.

[0008] In the present invention, the inventors unexpectedly found that in the system of the present invention, the use of modified fillers can better increase the gloss of the ink film, which may be because the modified fillers have better fluidity in the system.

[0009] Furthermore, the filler is selected from at least one of calcium carbonate, kaolin, montmorillonite and bentonite.

[0010] Furthermore, the filler is calcium carbonate and kaolin, and the weight ratio thereof is 1:(4-5).

[0011] Furthermore, the average particle size of the calcium carbonate is 2-3 microns.

[0012] The calcium carbonate in the present invention can be obtained commercially, for example, OMYA CARB 2 from Switzerland.

[0013] Furthermore, the average particle size of the kaolin is 0.1-0.3 microns.

[0014] The kaolin used in the present invention can be obtained from the market, for example, kaolin of model ASP G92 from BASF.

[0015] Furthermore, in step (1), the space velocity of HF gas is 200-500h-1, and the space velocity of water vapor is 50-100h-1. -1 The preferred HF gas space velocity is 300-350h -1 , the space velocity of water vapor is 80-100h -1 .

[0016] Furthermore, in step (1), the modification treatment conditions are: temperature of 200-250° C. and time of 60-80 minutes.

[0017] Furthermore, in step (2), 22-28 wt% of aqueous acrylic resin emulsion, 12-15 wt% of pigment, 15-20 wt% of modified filler, 15-16 wt% of cosolvent, 2-4 wt% of polyethylene wax, 0.08-0.12 wt% of neutralizer are prepared, and water is added to 100 wt% for standby use.

[0018] Furthermore, the raw materials for preparing the water-based acrylic resin are: a monomer mixture, sodium bicarbonate, a polymeric emulsifier DNS-86, ammonium persulfate, and water; the monomer mixture is a combination of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide, and the weight ratio of the methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is preferably 1:(1-1.5):(0.2-0.4):(0.05-0.1), preferably 1:(1.2-1.3):(0.23-0.25):(0.06-0.07).

[0019] Furthermore, the weight of the sodium bicarbonate is 0.07-0.08% of the weight of the monomer mixture.

[0020] Furthermore, the weight of the polymeric emulsifier DNS-86 is 1-3% of the weight of the monomer mixture, preferably 2-2.5%.

[0021] Furthermore, the weight of the ammonium persulfate is 0.1-0.5% of the weight of the monomer mixture, preferably 0.2-0.25%.

[0022] Furthermore, the weight of the water is 100-150% of the weight of the monomer mixture.

[0023] Furthermore, the preparation method of the water-based acrylic resin comprises: mixing water, a polymeric emulsifier DNS-86, 1 / 10 weight of a monomer mixture, and sodium bicarbonate, heating to 78±2° C., adding 1 / 3 weight of ammonium persulfate, heating to 82±2° C. for reaction for 0.5 hour, and then starting to drip the remaining monomer mixture, dripping the remaining monomer mixture at a controlled uniform speed, and completing the dripping in three hours, adding 1 / 3 weight of ammonium persulfate when the monomer mixture is dripped for one hour and two hours, respectively, and completing the dripping of ammonium persulfate twice within 1 hour, heating the monomer mixture to 88±2° C. after completion of dripping, keeping the temperature for 2 hours, and then naturally cooling to room temperature, using 90% ammonia water to neutralize the emulsion to a pH value of 6.5, filtering with a 100-mesh filter, and discharging to obtain a water-based acrylic resin.

[0024] Water-based ink uses water-based resin as a binder. In the present invention, the inventors have found through extensive research that the use of a specific monomer mixture of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide in the present invention, while controlling the ratio between the monomers, allows the ink to have an excellent printing dot effect. This may be because N,N-methylenebisacrylamide can produce a cross-linking effect, which makes the viscosity of the ink present a balanced and stable state, resulting in smooth transfer, no expansion of dots, and strong adhesion.

[0025] The specific type of pigment can be selected according to needs, and pigments commonly used in the ink field can be selected according to needs. Four-color printing can use four inks to mix an infinite variety of colors. Further, the pigment is selected from carbon black, 15:3 phthalocyanine blue, PY155 yellow or PR122 purple peach.

[0026] The main solvent of the water-based ink in the present invention is water, which can solve the problem that the organic solvents used before are harmful to the environment and human body. However, the surface tension of water is too large, which will affect the drying speed and water resistance of the ink. In order to improve this defect, a co-solvent is generally added to dissolve the resin to connect the pigment and the additive, giving the ink better water resistance and easy dissolution ability for the resin. However, the inventors of the present invention have found through research that in the system of the present invention, the use of water-alcohol co-solvents alone does not significantly improve the gloss of the ink film.

[0027] In order to better increase the glossiness of the ink film, further, the co-solvent is an alcohol co-solvent and an ionic liquid.

[0028] The inventors of the present invention have found through research that the use of alcohol co-solvents and ionic liquids as co-solvents in the system of the present invention can better improve the glossiness of the ink film. At the same time, by controlling the amount of co-solvents added in the ink components, the drying speed of the ink can also be improved. This may be because ionic liquids can dissolve in water and alcohol co-solvents. The dissolution system formed by the three makes the resin, and the system can better dissolve the resin, make the drying moderate, form a continuous and smooth ink film, and increase the glossiness of the ink film. At the same time, there are a large number of hydrogen bonds in the interaction form system of alcohol co-solvents and ionic liquids. The components of the system are interconnected due to the action of hydrogen bonds to form a three-dimensional network structure. After the ink is filmed, the ink film structure is more stable, and the water resistance of the ink is better improved.

[0029] Furthermore, the weight ratio of the co-solvent is an alcohol co-solvent to the ionic liquid is (1-5):1, for example, 1:1, 1.6:1, 2:1, 3:1, 4:1, 5:1, preferably (1.6-3):1.

[0030] In the present invention, by controlling the amount of alcohol cosolvent and ionic liquid, the effects of drying speed, good glossiness and balanced water resistance can be better achieved.

[0031] Further, the ionic liquid is selected from 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt (CAS No. 174899-82-2) and / or 1-butyl-3-methylimidazolium tetrafluoroborate (CAS No. 174501-65-6).

[0032] Furthermore, the alcohol co-solvent is selected from at least one of isopropanol, ethanol and methanol.

[0033] Furthermore, the alcohol solvent is selected from alcohol.

[0034] In the present invention, in order to better increase environmental protection, the alcohol is selected from edible alcohol, which is ordinary-grade edible alcohol with an ethanol content of 95% vol.

[0035] Polyethylene wax in ink can improve the flow phase of ink, improve the dispersibility of pigments and fillers, etc. The polyethylene wax in the present invention can be any polyethylene wax powder on the market, and its model can be 3620 wax powder.

[0036] The neutralizer can change the water solubility of the resin to a certain extent and affect the viscosity of the emulsion. Further, the neutralizer is selected from at least one of diethylamine, triethylamine, monoethanolamine, diethanolamine and triethanolamine, preferably monoethanolamine.

[0037] Furthermore, in step (3), the mixing and dispersing conditions are: a dispersing speed of 2000-3000 rpm and a dispersing time of 2-3 hours.

[0038] The second aspect of the present invention provides the use of the water-based fine dot ink prepared by the preparation method described in the first aspect of the present invention in securities, stamps or food packaging.

[0039] Compared with the prior art, the present invention has at least the following beneficial effects:

[0040] 1. When the existing water-based acrylic resin is used in ink, it can make the ink film strong, but its ink transferability and glossiness are poor. The present invention can increase the ink transferability and glossiness of the ink film through the synergistic effect between the specific components;

[0041] 2. The volatile organic compounds (VOCs) of the water-based ink of the present invention are less than 1.5;

[0042] 3. The water-based ink of the present invention can be used to print four-color halftone stamps. The transition of the stamp printing dots is very smooth, and the halftone ink can be completely transferred without the problem of poor transfer. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] Embodiment 1 of the present invention provides a method for preparing a water-based fine dot ink, the preparation method comprising:

[0046] (1) loading a filler into a reaction tube, introducing HF gas and water vapor to perform a modification treatment to obtain a modified filler;

[0047] (2) preparing 28 wt% of water-based acrylic resin emulsion, 12 wt% of pigment, 15 wt% of modified filler, 16 wt% of cosolvent, 2 wt% of polyethylene wax, 0.12 wt% of neutralizer, and water to 100 wt% for standby use;

[0048] (3) mixing and dispersing water-based acrylic resin, modified filler, cosolvent, polyethylene wax, neutralizer and water, and grinding the mixture to a fineness of less than 15 μm;

[0049] In step (1):

[0050] The fillers are calcium carbonate and kaolin, with a weight ratio of 1:4; the average particle size of calcium carbonate is 2.2 microns, and the model is Swiss OMYACARB 2; the average particle size of kaolin is 0.2 microns, and the model is ASP G92 kaolin from BASF; the space velocity of HF gas is 300h -1 , the space velocity of water vapor is 100h -1 The modification conditions are: temperature 230°C, time 60 minutes

[0051] In step (2):

[0052] The raw materials for preparing the water-based acrylic resin are: a monomer mixture, sodium bicarbonate, a polymeric emulsifier DNS-86, ammonium persulfate, and water; the monomer mixture is a combination of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide; the weight ratio of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is 1:1.2:0.23:0.07;

[0053] The weight of sodium bicarbonate is 0.07% of the weight of the monomer mixture; the weight of the polymeric emulsifier DNS-86 is 2.5% of the weight of the monomer mixture; the weight of ammonium persulfate is 0.25% of the weight of the monomer mixture; the weight of water is 100% of the weight of the monomer mixture;

[0054] The preparation method of water-based acrylic resin comprises: mixing water, polymeric emulsifier DNS-86, 1 / 10 weight of monomer mixture and sodium bicarbonate, heating to 78°C, adding 1 / 3 weight of ammonium persulfate, heating to 82°C for reaction for 0.5 hour, then dripping the remaining monomer mixture, controlling the dripping of the remaining monomer mixture at a uniform speed and completing the dripping in three hours, respectively adding 1 / 3 weight of ammonium persulfate when the monomer mixture is dripped for one hour and two hours, and the two drippings of ammonium persulfate are completed within one hour, heating the monomer mixture to 88°C after the dripping is completed, keeping the temperature for 2 hours, then cooling naturally to room temperature, neutralizing the emulsion with 90% ammonia water to a pH value of 6.5, filtering with a 100-mesh filter, and discharging to obtain water-based acrylic resin;

[0055] The pigment is carbon black; the cosolvent is an alcohol cosolvent and an ionic liquid; the weight ratio of the alcohol cosolvent to the ionic liquid is 2:1; the ionic liquid is 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonyl imide salt (CAS No. 174899-82-2); the alcohol cosolvent is edible alcohol, and the ethanol content is 95% vol; the polyethylene wax is 3620 wax powder; the neutralizer is monoethanolamine;

[0056] In step (3):

[0057] The mixing and dispersing conditions are: a dispersing speed of 2500 rpm and a dispersing time of 2 hours.

[0058] Example 2

[0059] Embodiment 2 of the present invention provides a method for preparing a water-based fine dot ink, the preparation method comprising:

[0060] (1) loading a filler into a reaction tube, introducing HF gas and water vapor to perform a modification treatment to obtain a modified filler;

[0061] (2) preparing 22 wt% of water-based acrylic resin emulsion, 15 wt% of pigment, 20 wt% of modified filler, 15 wt% of cosolvent, 4 wt% of polyethylene wax, 0.08 wt% of neutralizer, and water to 100 wt% for standby use;

[0062] (3) The water-based acrylic resin, the modified filler, the cosolvent, the polyethylene wax, the neutralizer and water are mixed and dispersed, and then ground to a fineness of less than 15 μm.

[0063] In step (1):

[0064] The filler is calcium carbonate and kaolin, with a weight ratio of 1:5; the average particle size of calcium carbonate is 2.2 microns, and the model is Swiss OMYACARB 2; the average particle size of kaolin is 0.2 microns, and the model is ASP G92 kaolin from BASF; the space velocity of HF gas is 350h -1 , the space velocity of water vapor is 80h -1 ; The modification treatment conditions are: temperature 250°C, time 80 minutes;

[0065] In step (2):

[0066] The raw materials for preparing the water-based acrylic resin are: a monomer mixture, sodium bicarbonate, a polymeric emulsifier DNS-86, ammonium persulfate, and water; the monomer mixture is a combination of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide; the weight ratio of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is 1:1.3:0.25:0.06; the weight of sodium bicarbonate is 0.08% of the weight of the monomer mixture; the weight of the polymeric emulsifier DNS-86 is 2% of the weight of the monomer mixture; the weight of ammonium persulfate is 0.2% of the weight of the monomer mixture; and the weight of water is 150% of the weight of the monomer mixture;

[0067] The preparation method of water-based acrylic resin comprises: mixing water, polymeric emulsifier DNS-86, 1 / 10 weight of monomer mixture and sodium bicarbonate, heating to 78°C, adding 1 / 3 weight of ammonium persulfate, heating to 82°C for reaction for 0.5 hour, then dripping the remaining monomer mixture, controlling the dripping of the remaining monomer mixture at a uniform speed and completing the dripping in three hours, respectively adding 1 / 3 weight of ammonium persulfate when the monomer mixture is dripped for one hour and two hours, and the two drippings of ammonium persulfate are completed within one hour, heating the monomer mixture to 88°C after the dripping is completed, keeping the temperature for 2 hours, then cooling naturally to room temperature, neutralizing the emulsion with 90% ammonia water to a pH value of 6.5, filtering with a 100-mesh filter, and discharging to obtain water-based acrylic resin;

[0068] The pigment is 15:3 phthalocyanine blue; the cosolvent is an alcohol cosolvent and an ionic liquid; the weight ratio of the alcohol cosolvent to the ionic liquid is 3:1; the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate (CAS No. 174501-65-6); the alcohol cosolvent is edible alcohol, and the ethanol content is 95% vol; the polyethylene wax is 3620 wax powder; and the neutralizer is monoethanolamine;

[0069] In step (3):

[0070] The mixing and dispersing conditions are: a dispersing speed of 3000 rpm and a dispersing time of 2 hours.

[0071] Example 3

[0072] Embodiment 1 of the present invention provides a method for preparing a water-based fine dot ink, the preparation method comprising:

[0073] (1) loading a filler into a reaction tube, introducing HF gas and water vapor to perform a modification treatment to obtain a modified filler;

[0074] (2) preparing 25 wt% of water-based acrylic resin emulsion, 15 wt% of pigment, 15 wt% of modified filler, 15 wt% of cosolvent, 3 wt% of polyethylene wax, 0.1 wt% of neutralizer, and water to 100 wt% for standby use;

[0075] (3) The water-based acrylic resin, the modified filler, the cosolvent, the polyethylene wax, the neutralizer and water are mixed and dispersed, and then ground to a fineness of less than 15 μm.

[0076] In step (1):

[0077] The filler is calcium carbonate and kaolin, with a weight ratio of 1:4.5; the average particle size of calcium carbonate is 2.2 microns, and the model is Swiss OMYACARB 2; the average particle size of kaolin is 0.2 microns, and the model is BASF's ASPG92 kaolin; the space velocity of HF gas is 320h-1 , the space velocity of water vapor is 85h -1 ; The modification treatment conditions are: temperature 230°C, time 65 minutes;

[0078] In step (2):

[0079] The raw materials for preparing the water-based acrylic resin are: a monomer mixture, sodium bicarbonate, a polymeric emulsifier DNS-86, ammonium persulfate, and water; the monomer mixture is a combination of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide; the weight ratio of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is 1:1.25:0.24:0.06; the weight of sodium bicarbonate is 0.08% of the weight of the monomer mixture; the weight of the polymeric emulsifier DNS-86 is 2.3% of the weight of the monomer mixture; the weight of ammonium persulfate is 0.24% of the weight of the monomer mixture; and the weight of water is 120% of the weight of the monomer mixture;

[0080] The preparation method of water-based acrylic resin comprises: mixing water, polymeric emulsifier DNS-86, 1 / 10 weight of monomer mixture and sodium bicarbonate, heating to 78°C, adding 1 / 3 weight of ammonium persulfate, heating to 82°C for reaction for 0.5 hour, then dripping the remaining monomer mixture, controlling the dripping of the remaining monomer mixture at a uniform speed and completing the dripping in three hours, respectively adding 1 / 3 weight of ammonium persulfate when the monomer mixture is dripped for one hour and two hours, and the two drippings of ammonium persulfate are completed within one hour, heating the monomer mixture to 88°C after the dripping is completed, keeping the temperature for 2 hours, then cooling naturally to room temperature, neutralizing the emulsion with 90% ammonia water to a pH value of 6.5, filtering with a 100-mesh filter, and discharging to obtain water-based acrylic resin;

[0081] The pigment is PY155 yellow; the cosolvent is an alcohol cosolvent and an ionic liquid; the weight ratio of the alcohol cosolvent to the ionic liquid is 1.67:1; the ionic liquid is 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt (CAS No. 174899-82-2); the alcohol cosolvent is edible alcohol, and the ethanol content is 95% vol; the polyethylene wax is 3620 wax powder; the neutralizer is monoethanolamine;

[0082] In step (3):

[0083] The mixing and dispersing conditions are as follows: a dispersing speed of 2500 rpm and a dispersing time of 2.5 hours.

[0084] Comparative Example 1

[0085] Comparative Example 1 provides a method for preparing a water-based ink, which is similar to Example 3, except that the co-solvent is an alcohol co-solvent and there is no ionic liquid.

[0086] Comparative Example 2

[0087] Comparative Example 2 provides a method for preparing a water-based ink, which is similar to Example 3, except that the weight ratio of the alcohol cosolvent to the ionic liquid is 0.8:1.

[0088] Comparative Example 3

[0089] Comparative Example 3 provides a method for preparing a water-based ink, which is similar to Example 3, except that: in step (2), 25wt% of water-based acrylic resin emulsion, 15wt% of pigment, 15wt% of modified filler, 30wt% of cosolvent, 3wt% of polyethylene wax, 0.1wt% of neutralizer are prepared, and water is added to 100wt% for use.

[0090] Comparative Example 4

[0091] Comparative Example 4 provides a method for preparing a water-based ink, which is similar to Example 3, except that the modified filler is replaced with a filler with a weight ratio of 1:4.5.

[0092] Comparative Example 5

[0093] Comparative Example 5 provides a method for preparing a water-based ink, which is similar to Example 3, except that the filler is kaolin and no calcium carbonate is present.

[0094] Comparative Example 6

[0095] Comparative Example 6 provides a method for preparing a water-based ink, which is similar to Example 3, except that the filler is calcium carbonate and kaolin.

[0096] Comparative Example 7

[0097] Comparative Example 7 provides a method for preparing a water-based ink, which is similar to Example 3, except that the monomer mixture is a combination of methyl methacrylate, acrylic acid, and butyl acrylate; the weight ratio of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is 1:1.25:0.24.

[0098] Comparative Example 8

[0099] Comparative Example 8 provides a method for preparing a water-based ink, which is similar to Example 3, except that the weight ratio of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is 1:1.25:0.24:0.3.

[0100] Performance Testing

[0101] The inks prepared in the examples and comparative examples were tested for their performance:

[0102] 1. Initial drying: measured in accordance with GB / T 13217.5-2008.

[0103] 2. Gloss: Measured using Linshang LS192 gloss meter according to the method in GB / T 13217.2-2009.

[0104] 3. Water resistance: According to the international standard ISO2836 Printing technology. Printed products and printing inks - Determination of water resistance.

[0105] 4. Testing of printing dot effect: The water-based ink prepared in the embodiment and the comparative example was respectively subjected to gravure printing, and the printing conditions included: plate depth 30-70 microns; printing speed: 6500 sheets / hour; paper: 90g offset paper, and the printed samples were tested after being completely dried. The dot effects of 3%, 10%, 80% and 90% were observed and analyzed using a 30-100 times magnifying glass. The dot effects without missing dots, diffusion, connected dots and hollows were qualified, and the presence of one or more of the missing dots, diffusion, connected dots and hollows was unqualified.

[0106] The test results are shown in Table 1.

[0107] Table 1: Performance Test

[0108]

[0109]

[0110]

[0111] From the results in Table 1, it can be seen that the water-based ink of the present invention has excellent ink transferability, glossiness and water resistance.

[0112] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a water-based fine dot ink, characterized in that: The preparation method comprises: (1) The filler is loaded into a reaction tube, and HF gas and water vapor are introduced to perform a modification treatment to obtain a modified filler; (2) Prepare 15-35wt% water-based acrylic resin, 8-20wt% pigment, 10-30wt% modified filler, 10-25wt% cosolvent, 1-5wt% polyethylene wax, 0.05-0.15wt% neutralizer, and water to 100wt% for standby use; (3) Mix and disperse the water-based acrylic resin, modified filler, cosolvent, polyethylene wax, neutralizer and water, and grind them to a fineness of less than 15 μm; The cosolvent is composed of an alcohol cosolvent and an ionic liquid in a weight ratio of (1-5):1; The ionic liquid is selected from 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonyl imide salt and / or 1-butyl-3-methylimidazolium tetrafluoroborate; The alcohol co-solvent is selected from at least one of isopropanol, ethanol and methanol; The filler is composed of calcium carbonate and kaolin in a weight ratio of 1: (4-5); The raw materials for preparing the water-based acrylic resin are: a monomer mixture, sodium bicarbonate, a polymeric emulsifier DNS-86, ammonium persulfate, and water; the monomer mixture is a combination of methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide, and the weight ratio of the methyl methacrylate, acrylic acid, butyl acrylate, and N,N-methylenebisacrylamide is 1: (1-1.5): (0.2-0.4): (0.05-0.1).

2. The preparation method according to claim 1, characterized in that: In step (1), the space velocity of HF gas is 200-500h -1 , the space velocity of water vapor is 50-100 h -1 The modification treatment conditions are: temperature 200-250°C, time 60-80 minutes.

3. The preparation method according to claim 1, characterized in that: The weight of the sodium bicarbonate is 0.07-0.08% of the weight of the monomer mixture; The weight of the polymeric emulsifier DNS-86 is 1-3% of the weight of the monomer mixture; The weight of the ammonium persulfate is 0.1-0.5% of the weight of the monomer mixture; The weight of the water is 100-150% of the weight of the monomer mixture.

4. The preparation method according to claim 1, characterized in that: The preparation method of the water-based acrylic resin comprises: mixing water, a polymeric emulsifier DNS-86, 1 / 10 weight of a monomer mixture and sodium bicarbonate and heating to 78±2° C., adding 1 / 3 weight of ammonium persulfate, heating to 82±2° C. for reaction for 0.5 hour, and then dripping the remaining monomer mixture, dripping the remaining monomer mixture at a controlled uniform speed and completing the dripping in three hours, respectively adding 1 / 3 weight of ammonium persulfate when the monomer mixture is dripped for one hour and two hours, and the two drippings of ammonium persulfate are completed within one hour, heating the monomer mixture to 88±2° C. after the dripping is completed, keeping the temperature for 2 hours, and then cooling naturally to room temperature, neutralizing the emulsion with 90% ammonia water to a pH value of 6.5, filtering with a 100-mesh filter, and discharging to obtain the water-based acrylic resin.

5. The preparation method according to claim 1, characterized in that: The pigment is selected from carbon black, 15:3 phthalocyanine blue, PY155 yellow or PR122 purple peach; The neutralizing agent is selected from at least one of diethylamine, triethylamine, monoethanolamine, diethanolamine and triethanolamine.

6. The preparation method according to claim 1, characterized in that: In step (3), the mixing and dispersing conditions are: a dispersing speed of 2000-3000 rpm and a dispersing time of 2-3 hours.

7. Use of the water-based fine dot ink prepared by the preparation method according to any one of claims 1 to 6 in securities, stamps or food packaging.

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