Weak solvent ink for inkjet printer and preparation method thereof

Abstract

The present application discloses a weak solvent ink for inkjet printers and a preparation method thereof, relating to the field of printing ink technology. A modified matrix resin is prepared by free radical polymerization of 4-hydroxystyrene and hydroxyethyl methacrylate; and the modified matrix resin is fully mixed with a solvent, modified barium carbonate, a pigment, a dispersant, a wetting agent, a defoamer, an antibacterial agent, and a pH regulator to prepare a weak solvent ink for inkjet printers. The ink has excellent antioxidant properties and excellent stability without the need for additional antioxidants. Furthermore, the ink evaporates and dries quickly after spraying, and the solvent used is environmentally friendly and harmless, reducing VOC emissions, and has broad application prospects.

Description

Technical Field

[0001] The present application relates to the technical field of printing inks, and in particular to a weak solvent ink for an inkjet printer and a preparation method thereof. Background Art

[0002] In the field of modern printing technology, inkjet printers, with their precise image reproduction capabilities and diverse application scenarios, serve a wide range of industries, including office, advertising, decoration, packaging, and textile printing and dyeing. Among them, eco-solvent inks, with their unique advantages, are gradually becoming one of the mainstream printing consumables.

[0003] However, traditional inkjet printing inks face severe oxidation challenges when facing outdoor applications or long-term storage needs. Whether it is outdoor advertising signs, car body stickers, or long-term preservation of artwork printing, oxidation will cause the ink color to fade, corrode the nozzle, and reduce print quality. To address this problem, the conventional practice is to add antioxidants to the ink. Although antioxidants can slow down the oxidation process to a certain extent, they also bring a series of disadvantages. On the one hand, the additional addition of antioxidants increases the complexity of the ink composition, and the compatibility of different antioxidants with other components in the ink system is difficult to guarantee, which can easily lead to ink stability problems such as precipitation, stratification, and even nozzle clogging. On the other hand, some antioxidants themselves have certain volatility or toxicity. As the ink is used, it will cause potential harm to the environment and the health of operators, which is contrary to the current development concept of green environmental protection and safe production.

[0004] Chinese patent application publication number CN 111662591A discloses a method for preparing a highly weather-resistant, weak-solvent inkjet ink for outdoor use. The ink comprises the following components by weight: 5-10 parts functional solid resin, 5-10 parts silicone solid resin, 5-10 parts organic pigment, 60-80 parts high-flash-point, environmentally friendly weak solvent, 0.1-2 parts UV absorber, 0.1-2 parts surfactant, 0.5-1 part dispersant, and 0.1-2 parts antioxidant. The ink not only exhibits excellent outdoor performance and weather resistance, resisting fading and shedding after prolonged outdoor use and resisting the effects of UV light, but also contains no toxic solvents such as benzene, toluene, xylene, and cyclohexanone, overcoming the drawback of most existing solvent-based inks, which tend to emit a significant amount of distinctive odor.

[0005] However, the above technical solution still requires the additional addition of antioxidants, and the stability of the ink still has a lot of room for improvement. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this application provides a weak-solvent ink for inkjet printers and a preparation method thereof. A modified base resin is prepared by free radical polymerization of 4-hydroxystyrene and hydroxyethyl methacrylate. This modified base resin is then thoroughly mixed with a solvent, modified barium carbonate, a pigment, a dispersant, a wetting agent, a defoamer, an antibacterial agent, and a pH adjuster to produce a weak-solvent ink for inkjet printers. This ink exhibits excellent antioxidant properties without the need for the addition of antioxidants and exhibits excellent stability, promising broad application prospects.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a weak solvent ink for an inkjet printer, comprising a modified base resin, a solvent, modified barium carbonate, a pigment, a dispersant, a wetting agent, a defoaming agent, an antibacterial agent and a pH regulator; the modified base resin is obtained by free radical polymerization of 4-hydroxystyrene and hydroxyethyl methacrylate.

[0009] In a second aspect, the present application provides a method for preparing eco-solvent ink for an inkjet printer, comprising the following steps:

[0010] Ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and initiator were added to a reactor protected by nitrogen;

[0011] The material in the reactor undergoes a free radical polymerization reaction at a first temperature for a first time, and a modified matrix resin is obtained after discharging the material;

[0012] adding the modified base resin to the solvent and stirring at a second temperature for a second time to obtain a resin solution;

[0013] mixing the pigment and the dispersant, adding the mixture to the resin solution, and stirring the mixture at the first speed for a third time;

[0014] Adding modified barium carbonate, a wetting agent, a defoaming agent, an antibacterial agent, and a pH regulator to the resin solution to adjust the pH to a predetermined range;

[0015] The resin solution was stirred at the first rotation speed for a fourth time, and filtered through a 0.5 μm filter element to obtain a weak solvent ink for an inkjet printer.

[0016] Beneficial technical effects:

[0017] The present application prepares a modified matrix resin having phenolic hydroxyl groups and hydroxyl groups connected to the main molecular chain by free radical polymerization of 4-hydroxystyrene and hydroxyethyl methacrylate. The phenolic hydroxyl group can provide hydrogen atoms to combine with free radicals such as peroxyl radicals ROO· and alkoxyl radicals RO· produced in the ink or the environment, converting them into stable non-radical products. At the same time, the stable phenoloxyl radicals generated by themselves interrupt the oxidation chain reaction. Therefore, it is not necessary to add antioxidants to prevent the oxidation and deterioration of the ink components, giving the ink a strong antioxidant capacity. At the same time, it avoids the compatibility of the added antioxidant with other components in the ink system that is difficult to ensure, resulting in sedimentation, stratification or volatilization, and other problems, thereby enhancing the stability of the ink. Moreover, the addition of modified barium carbonate can buffer the acidic components in the ink system, further enhancing the stability and antioxidant properties of the ink. In addition, the resin polymer chains generated by polymerization will form a physical cross-linked network after film formation, blocking oxygen and moisture penetration, delaying the photo-oxidative aging of the ink, and further improving the antioxidant properties of the ink. In addition, the presence of hydroxyl groups can cause hydrogen bonds or covalent bonds to form between the ink and the surface of the specific substrate (such as paper) on which it is sprayed, thereby enhancing the adhesion of the ink to the surface of the specific substrate (such as paper); on the other hand, the polarity of the hydroxyl group can also enhance the compatibility between the modified matrix resin and the solvent used in this application, further enhancing the stability of the ink, and making it easier for the solvent molecules to escape from the resin network, thereby accelerating the rate of evaporation and drying of the ink after spraying; and the solvent used in this application is environmentally friendly and harmless, reducing VOCs emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the chemical reaction for preparing the modified matrix resin.

[0019] Figure 2 It is a schematic diagram of the process of preparing weak solvent ink for inkjet printers.

[0020] Figure 3 This is a physical picture of the prepared weak solvent ink for inkjet printer. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions, and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the following examples. However, this should not be construed as limiting the scope of this application to the following examples. Without departing from the above-mentioned method concepts of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0022] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to be limiting of the application.

[0023] As used in this application, the singular forms "for," "a," "any," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0024] In addition, if the terms "first" and "second" appear in this application, they are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0025] In the first aspect, the present application provides an inkjet printer weak solvent ink, comprising a modified base resin, a solvent, modified barium carbonate, a pigment, a dispersant, a wetting agent, a defoaming agent, an antibacterial agent and a pH regulator; the modified base resin is obtained by free radical polymerization of 4-hydroxystyrene and hydroxyethyl methacrylate, the reaction being as follows Figure 1 shown.

[0026] In one possible implementation, the structure of the modified base resin includes:

[0027] Here, n is an integer between 10 and 50.

[0028] In one possible implementation, the mass ratio of the modified base resin, solvent, modified barium carbonate, pigment, dispersant, wetting agent, defoaming agent, antibacterial agent and pH regulator is (20-35): (40-50): (10-20): (8-15): (1-2): (0.5-1): (0.5-1): (0.5-1): (1-3).

[0029] In one possible implementation, the method for preparing the modified barium carbonate includes:

[0030] At 60-80°C, add the carbonate solution dropwise into the barium salt solution while stirring, and add the titanate solution at the same time, controlling the dropping rate to maintain the pH at 8-10;

[0031] Continue stirring for 30 to 60 minutes, filter out the solid, and wash the solid with deionized water and anhydrous ethanol two to three times.

[0032] The cleaned solid is vacuum dried at 60-80° C. for 4-8 hours, and pulverized through a 200-mesh sieve to obtain modified barium carbonate.

[0033] In a possible implementation, the titanate coupling agent is used in an amount of 0.5 to 1.5% by mass of the barium salt solution; the titanate coupling agent includes at least one of titanate coupling agent TC-2, titanate coupling agent TC-27, and titanate coupling agent TC-114.

[0034] In a possible implementation, the solvent includes at least one of diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, diethylene glycol tetramethyl ether, and methyl tert-butyl ether.

[0035] In a possible implementation, the pigment includes any one of carbon black, titanium dioxide, phthalocyanine blue, quinacridone red, and benzimidazolone yellow.

[0036] In a possible implementation, the dispersant includes any one of BYK-163, EFKA-4010, and tributyl phosphate.

[0037] In a possible implementation, the wetting agent includes any one of BYK-346, BYK-348, and Capstone FS-3100.

[0038] In a possible implementation, the defoaming agent includes any one of dimethyl silicone oil and polyoxyethylene polyoxypropylene glycerol ether.

[0039] In a possible implementation, the antibacterial agent includes any one of 2-n-octyl-4-isothiazoline-3-one and 1,2-benzisothiazolin-3-one.

[0040] In a possible implementation, the pH adjuster includes any one of N,N-dimethylethylamine, triethanolamine, and 2-amino-2-methyl-1-propanol.

[0041] In a second aspect, the present application provides a method for preparing a weak solvent ink for an inkjet printer, such as Figure 2 As shown, the following steps are included:

[0042] Ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and initiator were added to a reactor protected by nitrogen;

[0043] The material in the reactor undergoes a free radical polymerization reaction at a first temperature for a first time, and a modified matrix resin is obtained after discharging the material;

[0044] adding the modified base resin to the solvent and stirring at a second temperature for a second time to obtain a resin solution;

[0045] mixing the pigment and the dispersant, adding the mixture to the resin solution, and stirring the mixture at the first speed for a third time;

[0046] Adding modified barium carbonate, a wetting agent, a defoaming agent, an antibacterial agent, and a pH regulator to the resin solution to adjust the pH to a predetermined range;

[0047] The resin solution was stirred at the first speed for a fourth time, and filtered through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink, such as Figure 3shown.

[0048] In a possible implementation, the mass ratio of the ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and initiator is (60-70): (10-20): (15-25): (0.5-1).

[0049] In a possible implementation, the initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and lauroyl peroxide.

[0050] In one possible implementation, the first temperature is 70-80°C, the second temperature is 50-60°C; the first time is 6-8 hours, the second time is 1-2 hours, the third time is 0.5-1 hour, and the fourth time is 10-20 minutes; the first rotation speed is 800-1200 rpm; and the predetermined pH range is 8-9.

[0051] The following will describe in detail an inkjet printer eco-solvent ink and a preparation method thereof provided by the present application in combination with different embodiments.

[0052] Example 1:

[0053] like Figure 2 As shown, a method for preparing a weak solvent ink for an inkjet printer comprises the following steps:

[0054] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisobutyronitrile into a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisobutyronitrile is 65:15:19:1.

[0055] 2. Carry out free radical polymerization at 75°C for 7 hours to obtain a modified matrix resin;

[0056] 3. Add the modified base resin to diethylene glycol methyl ethyl ether and stir at 55°C for 1.5 hours to obtain a resin solution;

[0057] 4. Mix carbon black and BYK-163 and add them to the resin solution. Stir at 1000 rpm for 0.5 h.

[0058] 5. Add modified barium carbonate, BYK-346, dimethyl silicone oil, 2-n-octyl-4-isothiazoline-3-one and triethanolamine to the resin solution and adjust the pH to 8.5;

[0059] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0060] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol methyl ethyl ether, modified barium carbonate, carbon black, BYK-163, BYK-346, dimethyl silicone oil, 2-n-octyl-4-isothiazoline-3-one and triethanolamine is 25:48:10:11:1.5:0.8:0.6:0.5:2.6.

[0061] Example 2:

[0062] like Figure 2 As shown, a method for preparing a weak solvent ink for an inkjet printer comprises the following steps:

[0063] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and lauroyl peroxide into a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and lauroyl peroxide is 70:12:17.5:0.5.

[0064] 2. Carry out free radical polymerization at 80°C for 6 hours to obtain a modified matrix resin;

[0065] 3. Add the modified base resin to diethylene glycol tetramethyl ether and stir at 60°C for 2 hours to obtain a resin solution;

[0066] 4. Mix titanium dioxide and EFKA-4010 and add them to the resin solution, stirring at 1200 rpm for 1 hour;

[0067] 5. Add modified barium carbonate, BYK-348, polyoxyethylene polyoxypropylene glycerol ether, 1,2-benzisothiazolin-3-one and N,N-dimethylethylamine to the resin solution and adjust the pH to 8.8;

[0068] 6. Continue stirring the resin solution at 1200 rpm for 10 min, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0069] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol tetramethyl ether, modified barium carbonate, titanium dioxide, EFKA-4010, BYK-348, polyoxyethylene polyoxypropylene glycerol ether, 1,2-benzisothiazolin-3-one and N,N-dimethylethylamine is 30:40:12:13:2:0.5:0.5:0.5:1.5.

[0070] Example 3:

[0071] like Figure 2 As shown, a method for preparing a weak solvent ink for an inkjet printer comprises the following steps:

[0072] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisoheptanonitrile to a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisoheptanonitrile is 62:15:22:1.

[0073] 2. Carry out free radical polymerization at 70°C for 8 hours to obtain a modified matrix resin;

[0074] 3. Add the modified base resin to methyl tert-butyl ether and stir at 50°C for 1 hour to obtain a resin solution;

[0075] 4. Mix quinacridone red and tributyl phosphate and add them to the resin solution. Stir at 800 rpm for 0.75 h.

[0076] 5. Add modified barium carbonate, Capstone FS-3100, polyoxyethylene polyoxypropylene glycerol ether, 2-n-octyl-4-isothiazoline-3-one and 2-amino-2-methyl-1-propanol to the resin solution and adjust the pH to 9;

[0077] 6. Continue stirring the resin solution at 800 rpm for 20 min, and filter it through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0078] In the above steps 3 to 6, the mass ratio of the modified base resin, methyl tert-butyl ether, modified barium carbonate, quinacridone red, tributyl phosphate, Capstone FS-3100, polyoxyethylene polyoxypropylene glycerol ether, 2-n-octyl-4-isothiazoline-3-one and 2-amino-2-methyl-1-propanol is 25:45:15:9:1:0.8:0.7:0.5:3.

[0079] Example 4:

[0080] like Figure 2 As shown, a method for preparing a weak solvent ink for an inkjet printer comprises the following steps:

[0081] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisobutyronitrile into a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisobutyronitrile is 66:12:21:1.

[0082] 2. Carry out free radical polymerization at 78°C for 7.5 hours to obtain a modified matrix resin;

[0083] 3. Add the modified base resin to diethylene glycol diethyl ether and stir at 55°C for 1 hour to obtain a resin solution;

[0084] 4. Mix benzimidazolone yellow and BYK-163, add them to the resin solution, and stir at 1000 rpm for 0.5 h;

[0085] 5. Add modified barium carbonate, BYK-346, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and triethanolamine to the resin solution and adjust the pH to 8.3;

[0086] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0087] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol diethyl ether, modified barium carbonate, benzimidazolone yellow, BYK-163, BYK-346, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and triethanolamine is 24:46:14:12:1:0.5:0.5:0.5:1.5.

[0088] Example 5:

[0089] like Figure 2 As shown, a method for preparing a weak solvent ink for an inkjet printer comprises the following steps:

[0090] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and lauroyl peroxide into a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and lauroyl peroxide is 60:14.2:25:0.8;

[0091] 2. Carry out free radical polymerization at 72°C for 7 hours to obtain a modified matrix resin;

[0092] 3. Add the modified base resin to diethylene glycol methyl ethyl ether and stir at 58°C for 1.5 hours to obtain a resin solution;

[0093] 4. Mix phthalocyanine blue and EFKA-4010 and add them to the resin solution. Stir at 900 rpm for 1 hour.

[0094] 5. Add modified barium carbonate, BYK-348, polyoxyethylene polyoxypropylene glycerol ether, 2-n-octyl-4-isothiazoline-3-one and N,N-dimethylethylamine to the resin solution and adjust the pH to 8.3;

[0095] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0096] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol methyl ethyl ether, modified barium carbonate, phthalocyanine blue, EFKA-4010, BYK-348, polyoxyethylene polyoxypropylene glycerol ether, 2-n-octyl-4-isothiazoline-3-one and N,N-dimethylethylamine is 25:44:15:11:1.5:0.7:0.6:0.5:1.7.

[0097] Example 6:

[0098] like Figure 2 As shown, a method for preparing a weak solvent ink for an inkjet printer comprises the following steps:

[0099] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisoheptanonitrile to a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisoheptanonitrile is 63:17:19.5:0.5.

[0100] 2. Carry out free radical polymerization at 76°C for 6.5 hours to obtain a modified matrix resin;

[0101] 3. Add the modified base resin to diethylene glycol tetramethyl ether and stir at 53°C for 1.2 hours to obtain a resin solution;

[0102] 4. Mix titanium dioxide and tributyl phosphate and add them to the resin solution, stirring at 1100 rpm for 0.8 h;

[0103] 5. Add modified barium carbonate, Capstone FS-3100, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and 2-amino-2-methyl-1-propanol to the resin solution and adjust the pH to 8.7;

[0104] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0105] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol tetramethyl ether, modified barium carbonate, titanium dioxide, tributyl phosphate, Capstone FS-3100, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and 2-amino-2-methyl-1-propanol is 26:48:11:10:1.5:0.6:0.4:0.5:2.

[0106] Comparative Example 1:

[0107] A method for preparing eco-solvent ink for an inkjet printer comprises the following steps:

[0108] 1. Add ethanol, styrene, hydroxyethyl methacrylate and azobisisobutyronitrile into a nitrogen-protected reactor. The mass ratio of ethanol, styrene, hydroxyethyl methacrylate and azobisisobutyronitrile is 65:15:19:1.

[0109] 2. Carry out free radical polymerization at 75°C for 7 hours to obtain a modified matrix resin;

[0110] 3. Add the modified base resin to diethylene glycol methyl ethyl ether and stir at 55°C for 1.5 hours to obtain a resin solution;

[0111] 4. Mix carbon black and BYK-163 and add them to the resin solution. Stir at 1000 rpm for 0.5 h.

[0112] 5. Add modified barium carbonate, BYK-346, dimethyl silicone oil, 2-n-octyl-4-isothiazoline-3-one and triethanolamine to the resin solution and adjust the pH to 8.5;

[0113] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0114] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol methyl ethyl ether, modified barium carbonate, carbon black, BYK-163, BYK-346, dimethyl silicone oil, 2-n-octyl-4-isothiazoline-3-one and triethanolamine is 25:48:10:11:1.5:0.8:0.6:0.5:2.6.

[0115] Comparative Example 2:

[0116] A method for preparing eco-solvent ink for an inkjet printer comprises the following steps:

[0117] 1. Add ethanol, 4-hydroxystyrene, ethyl methacrylate and azobis(isoheptanonitrile) into a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, ethyl methacrylate and azobis(isoheptanonitrile) is 62:15:22:1.

[0118] 2. Carry out free radical polymerization at 70°C for 8 hours to obtain a modified matrix resin;

[0119] 3. Add the modified base resin to methyl tert-butyl ether and stir at 50°C for 1 hour to obtain a resin solution;

[0120] 4. Mix quinacridone red and tributyl phosphate and add them to the resin solution. Stir at 800 rpm for 0.75 h.

[0121] 5. Add modified barium carbonate, Capstone FS-3100, polyoxyethylene polyoxypropylene glycerol ether, 2-n-octyl-4-isothiazoline-3-one and 2-amino-2-methyl-1-propanol to the resin solution and adjust the pH to 9;

[0122] 6. Continue stirring the resin solution at 800 rpm for 20 min, and filter it through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0123] In the above steps 3 to 6, the mass ratio of the modified base resin, methyl tert-butyl ether, modified barium carbonate, quinacridone red, tributyl phosphate, Capstone FS-3100, polyoxyethylene polyoxypropylene glycerol ether, 2-n-octyl-4-isothiazoline-3-one and 2-amino-2-methyl-1-propanol is 25:45:15:9:1:0.8:0.7:0.5:3.

[0124] Comparative Example 3:

[0125] A method for preparing eco-solvent ink for an inkjet printer comprises the following steps:

[0126] 1. Add ethanol, styrene, ethyl methacrylate and azobis(2-isoheptanonitrile) into a nitrogen-protected reactor. The mass ratio of ethanol, styrene, ethyl methacrylate and azobis(2-isoheptanonitrile) is 63:17:19.5:0.5.

[0127] 2. Carry out free radical polymerization at 76°C for 6.5 hours to obtain a modified matrix resin;

[0128] 3. Add the modified base resin to diethylene glycol tetramethyl ether and stir at 53°C for 1.2 hours to obtain a resin solution;

[0129] 4. Mix titanium dioxide and tributyl phosphate and add them to the resin solution, stirring at 1100 rpm for 0.8 h;

[0130] 5. Add modified barium carbonate, Capstone FS-3100, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and 2-amino-2-methyl-1-propanol to the resin solution and adjust the pH to 8.7;

[0131] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0132] In the above steps 3 to 6, the mass ratio of the modified base resin, diethylene glycol tetramethyl ether, modified barium carbonate, titanium dioxide, tributyl phosphate, Capstone FS-3100, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and 2-amino-2-methyl-1-propanol is 26:48:11:10:1.5:0.6:0.4:0.5:2.

[0133] Comparative Example 4: (without adding barium carbonate)

[0134] A method for preparing eco-solvent ink for an inkjet printer comprises the following steps:

[0135] 1. Add ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisobutyronitrile into a nitrogen-protected reactor. The mass ratio of ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and azobisisobutyronitrile is 66:12:21:1.

[0136] 2. Carry out free radical polymerization at 78°C for 7.5 hours to obtain a modified matrix resin;

[0137] 3. Add the modified base resin to diethylene glycol diethyl ether and stir at 55°C for 1 hour to obtain a resin solution;

[0138] 4. Mix benzimidazolone yellow and BYK-163, add them to the resin solution, and stir at 1000 rpm for 0.5 h;

[0139] 5. Add BYK-346, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and triethanolamine to the resin solution and adjust the pH to 8.3;

[0140] 6. Continue stirring the resin solution at 1000 rpm for 15 minutes, and filter through a 0.5 μm filter element to obtain an inkjet printer eco-solvent ink.

[0141] In steps 3 to 6 above, the mass ratio of the modified base resin, diethylene glycol diethyl ether, benzimidazolone yellow, BYK-163, BYK-346, dimethyl silicone oil, 1,2-benzisothiazolin-3-one and triethanolamine is 34:50:12:1:0.5:0.5:0.5:1.5.

[0142] The redox potential of the weak solvent ink prepared in the present application was tested by an electrochemical workstation, and the oxidation resistance of the weak solvent ink prepared was reflected by the magnitude of the redox potential.

[0143] Referring to QB / T 5489-2020, the absorbance of the weak solvent ink prepared in this application was tested before and after centrifugation (3000 rpm / min, 10 min) by the sedimentation stability test method, and its specific absorbance was calculated. The value of the specific absorbance reflects its stability.

[0144] Table 1 Test results of the weak solvent inks for inkjet printers prepared in the examples and comparative examples

[0145]

[0146]

[0147] As shown in Table 1, the redox potential and specific absorbance of Examples 1-6 are better than those of Comparative Examples 1-3.

[0148] The reason is that in Examples 1 to 6, 4-hydroxystyrene and hydroxyethyl methacrylate are subjected to free radical polymerization to prepare a modified matrix resin with phenolic hydroxyl groups and hydroxyl groups connected to the molecular backbone. The phenolic hydroxyl groups can provide hydrogen atoms to combine with free radicals such as peroxyl radicals ROO· and alkoxyl radicals RO· generated in the ink or the environment, converting them into stable non-radical products. At the same time, the stable phenoloxyl radicals generated by the resin interrupt the oxidation chain reaction. Therefore, the ink components can be prevented from oxidative deterioration without the addition of antioxidants, giving the ink strong antioxidant capacity. At the same time, the compatibility of added antioxidants with other components in the ink system, which may lead to sedimentation, stratification, or volatilization, is avoided, thereby enhancing the stability of the ink. Moreover, the addition of modified barium carbonate can buffer the acidic components in the ink system, further enhancing the stability and antioxidant properties of the ink. In addition, the resin polymer chains generated by polymerization form a physical cross-linked network after film formation, blocking the penetration of oxygen and moisture, delaying the photo-oxidative aging of the ink, and further improving the antioxidant properties of the ink. In addition, the presence of hydroxyl groups can cause hydrogen bonds or covalent bonds between the ink and the surface of the specific substrate (such as paper) on which it is sprayed, which on the one hand enhances the adhesion of the ink to the surface of the specific substrate (such as paper); on the other hand, the polarity of the hydroxyl group can also enhance the compatibility between the modified base resin and the solvent used in this application, further enhancing the stability of the ink.

[0149] In Comparative Example 1, 4-hydroxystyrene was not polymerized with hydroxyethyl methacrylate. Instead, phenolic hydroxyl group-free styrene was used. This made it difficult to provide hydrogen atoms to combine with free radicals generated in the ink or the environment, significantly reducing the ink's antioxidant properties. Furthermore, the relatively poor polarity of the benzene ring, which does not contain phenolic hydroxyl groups, resulted in poor compatibility between the resin and the solvent, and consequently reduced ink stability. In Comparative Example 2, hydroxyethyl methacrylate was not polymerized with 4-hydroxystyrene. Instead, hydroxyl-free ethyl methacrylate was used. Consequently, compatibility between the resin and the solvent decreased, film-forming properties were weakened, and the antioxidant properties of the ink were also reduced. Comparative Example 3 used phenolic hydroxyl group-free styrene and hydroxyl-free ethyl methacrylate. For the same reasons as in Comparative Examples 1 and 2, the final ink exhibited the worst antioxidant properties and stability. Furthermore, no modified barium carbonate was added to Comparative Example 4, making it difficult to buffer the acidic components in the ink system. Consequently, the final ink's stability and antioxidant properties were also poor.

[0150] The above results show and describe the basic principles and main features of this application as well as the advantages of this application.

[0151] Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in the present application is defined by the equivalents of the appended claims.

Claims

1. A weak solvent ink for an inkjet printer, characterized in that: The invention comprises a modified base resin, a solvent, modified barium carbonate, a pigment, a dispersant, a wetting agent, a defoaming agent, an antibacterial agent and a pH regulator; the modified base resin is obtained by free radical polymerization of 4-hydroxystyrene and hydroxyethyl methacrylate; The structure of the modified matrix resin includes: ; Wherein, n is an integer between 10 and 50; The preparation method of the modified barium carbonate comprises: At 60-80°C, add the carbonate solution dropwise into the barium salt solution while stirring, and add the titanate coupling agent at the same time, controlling the dripping rate to maintain the pH at 8-10; Continue stirring for 30-60 minutes, filter out the solid, and wash the solid two to three times with deionized water and anhydrous ethanol. The cleaned solid is vacuum dried at 60-80°C for 4-8 hours, and pulverized through a 200-mesh sieve to obtain modified barium carbonate.

2. The eco-solvent ink for inkjet printer according to claim 1, characterized in that: The mass ratio of the modified base resin, solvent, modified barium carbonate, pigment, dispersant, wetting agent, defoaming agent, antibacterial agent and pH regulator is (20-35): (40-50): (10-20): (8-15): (1-2): (0.5-1): (0.5-1): (0.5-1): (1-3).

3. The eco-solvent ink for inkjet printer according to claim 1, characterized in that: The solvent includes at least one of diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, diethylene glycol tetramethyl ether, and methyl tert-butyl ether.

4. The eco-solvent ink for inkjet printer according to claim 1, characterized in that: The pigment includes any one of carbon black, titanium dioxide, phthalocyanine blue, quinacridone red and benzimidazolone yellow.

5. The eco-solvent ink for inkjet printer according to claim 1, characterized in that: The pH adjuster includes any one of N,N-dimethylethylamine, triethanolamine and 2-amino-2-methyl-1-propanol.

6. The method for preparing a weak solvent ink for an inkjet printer according to any one of claims 1 to 5, characterized in that: The following steps are involved: Ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and initiator were added to a reactor protected by nitrogen; The material in the reactor undergoes a free radical polymerization reaction at a first temperature for a first time, and a modified matrix resin is obtained after discharging the material; adding the modified base resin to the solvent and stirring at a second temperature for a second time to obtain a resin solution; mixing the pigment and the dispersant, adding the mixture to the resin solution, and stirring the mixture at the first speed for a third time; Adding modified barium carbonate, a wetting agent, a defoaming agent, an antibacterial agent, and a pH regulator to the resin solution to adjust the pH to a predetermined range; The resin solution was stirred at the first rotation speed for a fourth time, and filtered through a 0.5 μm filter element to obtain a weak solvent ink for an inkjet printer.

7. The method for preparing a weak solvent ink for an inkjet printer according to claim 6, wherein: The mass ratio of the ethanol, 4-hydroxystyrene, hydroxyethyl methacrylate and initiator is (60-70): (10-20): (15-25): (0.5-1).

8. The method for preparing eco-solvent ink for inkjet printer according to claim 6, characterized in that: The initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile and lauroyl peroxide.

9. The method for preparing eco-solvent ink for inkjet printer according to claim 6, characterized in that: The first temperature is 70~80℃, the second temperature is 50~60℃; the first time is 6~8h, the second time is 1~2h, the third time is 0.5~1h, and the fourth time is 10~20min; the first speed is 800~1200rpm; and the predetermined pH range is 8~9.

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