Low-viscosity emulsion ink composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of ink, and particularly relates to a low-viscosity emulsified ink composition as well as a preparation method and application thereof. The nano carbon black ink is prepared from the following components: 3 to 10 percent of nano carbon black pigment, 5 to 15 percent of solvent type dye, 0.1 to 5 percent of wetting dispersant, 1 to 5 percent of nonionic fluorine modified emulsifier, 0.1 to 3 percent of pH regulator, 0.5 to 5 percent of lubricant, 5 to 25 percent of humectant, 0.1 to 1.0 percent of antibacterial preservative, 10 to 50 percent of organic solvent and the balance of distilled water, the nonionic fluorine modified emulsifier is a polyurethane polymer containing a fluorocarbon chain CnF2n + 1 structure, and n is less than or equal to 6 and is a natural number. The prepared ink is stable in system, strong in covering performance, bright in color, excellent in light resistance and water resistance, environmentally friendly, low in viscosity and suitable for products such as direct-liquid type ball-point pens and ink-jet printers with the requirement for low viscosity of ink in the market.

Description

Technical Field

[0001] The present invention belongs to the technical field of inks, and in particular relates to a low-viscosity emulsified ink composition, a preparation method and an application thereof. Background Art

[0002] Traditional writing or machine inks are primarily classified into two categories: oil-based and water-based. These two types of inks have distinct differences: Oil-based inks offer advantages in terms of stability, smoothness, and color vividness, but they often use large amounts of volatile organic solvents, which pose potential health risks. Water-based inks, while using water as a solvent, significantly improve their environmental friendliness, but they can also lead to drawbacks such as ink buildup and line breakage. In response to this, a new type of ink—emulsion ink—has emerged in recent years. This partially replaces the organic solvent with water, creating an oil-in-water or oil-in-water emulsion system. This not only reduces the use of organic solvents, making it more environmentally friendly, but also combines most of the advantages of both traditional water-based and oil-based inks.

[0003] The emulsion ink system is a thermodynamically unstable system with relatively poor storage stability. To address the technical difficulties of poor emulsion ink stability, existing disclosed emulsion ink preparation methods generally use macromolecular resin emulsifiers, supplemented by thickening and suspending agents, to stabilize the emulsion ink system. Although these formulations solve the storage stability problem of the emulsion ink, the use of macromolecular resins and thickening and suspending agents causes the viscosity of the emulsion ink to reach hundreds to thousands of centipoises at room temperature. Emulsion inks of this viscosity can meet the requirements of general gel pens and printers, but if used in inkjet printers, the nozzles will be clogged and the ink will not be sprayed smoothly. Moreover, since the water guide core and pen tip of a direct liquid ballpoint pen are thin, inks of this viscosity cannot flow smoothly in the pen, resulting in line breakage or even inability to write. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-viscosity emulsion ink composition and its preparation method and application, so as to overcome the shortcomings of the existing technology. The prepared ink system is stable, has strong covering power, bright color, excellent light resistance and water resistance, is environmentally friendly, and has low viscosity. It can be applied to direct liquid ballpoint pens, inkjet printers and other products on the market that require low viscosity ink.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] In a first aspect, the present invention provides a low-viscosity emulsion ink composition, which is composed of the following components, by mass percentage: 3-10% nano carbon black pigment, 5-15% solvent-based dye, 0.1-5% wetting dispersant, 1-5% non-ionic fluorine-modified emulsifier, 0.1-3% pH adjuster, 0.5-5% lubricant, 5-25% humectant, 0.1-1.0% bactericidal preservative, 10-50% organic solvent, and the balance is distilled water;

[0007] The nonionic fluorine-modified emulsifier is a fluorine-containing carbon chain C n F 2n+1 A polyurethane polymer with a structure wherein n≤6 and n is a natural number.

[0008] In some other embodiments, the composition is composed of the following components, calculated by mass percentage: 5-10% nano carbon black pigment, 5-10% solvent-based dye, 0.1-3% wetting dispersant, 2-5% non-ionic fluorine-modified emulsifier, 0.1-2% pH adjuster, 0.5-3% lubricant, 5-20% moisturizer, 0.1-0.5% bactericidal preservative, 15-50% organic solvent, and the balance is distilled water.

[0009] In some other embodiments, the pH value of the low viscosity emulsion ink composition is in the range of 7-9; at 25°C and a shear rate of 384s -1 The viscosity is 3-10mPa·s; the tension is 25.8-27.3mN / m.

[0010] In some other embodiments, the preparation method of the nonionic fluorine-modified emulsifier comprises the following steps:

[0011] (1) mixing isophorone diisocyanate and a catalyst to prepare a mixed solution; adding dropwise a fluoroalcohol acetone solution to the mixed solution to react and prepare an intermediate;

[0012] (2) The intermediate obtained in (1) is added dropwise to polyethylene glycol to react, and the solvent is removed in vacuo to obtain a nonionic fluorine-modified emulsifier.

[0013] In some other embodiments, in step (1), the amount of the catalyst added is 2-15% of the amount of isophorone diisocyanate added;

[0014] The dropping is carried out under normal pressure and the dropping temperature is 55-65°C;

[0015] The reaction time is 7-10h;

[0016] The concentration of the acetone solution of fluoroalcohol is 30-70%;

[0017] The molar ratio of the fluoroalcohol to isophorone diisocyanate is (0.9-1.1):1;

[0018] The catalyst is one or more of bismuth isooctanoate, bismuth laurate, bisdimethyltin and tetrabutyltin;

[0019] The fluoroalcohol is one or more of pentafluoropropanol, hexafluoroisopropanol, perfluorobutyl ethyl alcohol and trifluoroethanol.

[0020] In some other embodiments, in step (2), the molar ratio of polyethylene glycol to isophorone diisocyanate is (0.9-1.1):1;

[0021] The dropping is carried out under normal pressure and the dropping temperature is 60°C;

[0022] The reaction time is 8h;

[0023] The polyethylene glycol is one or more of PEG200, PEG400 and PEG600.

[0024] In some other embodiments, the solvent-based dye is one or more of Runba D45, Runba D55-V, BASF X51, BASF X55, Wenzhou Aotelai 929 Black, and Wenzhou Aotelai 959 Black;

[0025] The wetting and dispersing agent is one or more of Dow X405, Dow CF-10, Wanzhao 190 and Digo 760W dispersants;

[0026] The pH regulator is one or more of triethanolamine, monoethanolamine and isopropanolamine;

[0027] The lubricant is one or more of phosphate ester, oleic acid, polyvinyl alcohol and silicone resin;

[0028] The moisturizing agent is one or more of glycerol, ethylene glycol, hydroxyethyl urea, diethylene glycol and sorbitol;

[0029] The bactericidal preservative is one or more of methylisothiazolinone, chloroisothiazolinone and methyl parahydroxybenzoate;

[0030] The organic solvent is one or more of n-methylpyrrolidone, dimethylformamide, dimethylacetamide, ethyl carbitol, dimethyl sulfoxide, ethanol and isopropanol;

[0031] In a second aspect, the present invention provides a method for preparing a low-viscosity emulsion ink, using the low-viscosity emulsion ink composition described in the first aspect, comprising the following steps:

[0032] (1) mixing the nano carbon black pigment and the water-soluble wetting dispersant uniformly, and preparing a phase A solution after soaking;

[0033] (2) dissolving the solvent-based dye in an organic solvent, adding a nonionic fluorine-modified emulsifier, and stirring uniformly to prepare a phase B solution;

[0034] (3) After mixing the phase A solution, the phase B solution, the pH regulator, the lubricant, the moisturizer, and the bactericidal preservative, the mixture is emulsified and then ball-milled to obtain a low-viscosity emulsified ink.

[0035] In some other embodiments, the soaking time is greater than 24 hours;

[0036] The emulsification speed is 2000-3000 rpm, and the emulsification time is 20-30 min;

[0037] The ball milling speed is 400-600 rpm;

[0038] The particle size D90 of the low-viscosity emulsion ink is 150-200 nm.

[0039] In a third aspect, the present invention provides use of the low-viscosity emulsified ink composition described in the first aspect in a direct liquid ballpoint pen and an inkjet printer.

[0040] Beneficial effects of the present invention:

[0041] (1) The nonionic fluorine-modified emulsifier used in the present invention is a polyurethane polymer containing a short fluorine-carbon chain structure, and its unique fluorine structure imparts high surface activity, high thermal stability, and high chemical stability. In the preparation method of the nonionic fluorine-modified emulsifier, the PEG used is a PEG with a small molecular weight (PEG200, 400 or 600), which can reduce the impact on the viscosity of the system while ensuring the emulsification effect, and the added amount is 0.9-1.1 times the molar amount of IPDI, which can not only ensure the end-capping of the NCO group and improve the storage stability, but also reduce the adverse effects of unreacted PEG on the emulsified ink system.

[0042] (2) The solvent-based dye used in the present invention is an alcohol-soluble dye. This type of dye is easier to emulsify in water, and the resulting emulsified ink is more stable and has a lower viscosity. The wetting and dispersing agent can not only wet and disperse the nano-carbon black pigment, but also synergize with the non-ionic fluorine-modified emulsifier to improve the emulsification uniformity and stability of the emulsified ink. The pH regulator adjusts the pH of the emulsified ink to 7-9, ensuring the stability of the emulsified ink itself without damaging the pen tip, nozzle and other components. The organic solvent is a hydrophilic solvent that can both dissolve the dye and synergize with the emulsified ink.

[0043] (3) The ink system prepared by the present invention is stable, has strong covering power, bright color, excellent light resistance and water resistance, is environmentally friendly, and has low viscosity. It can be applied to products on the market that require low viscosity ink, such as direct liquid ballpoint pens and inkjet printers. DETAILED DESCRIPTION

[0044] Those skilled in the art will appreciate that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the examples were performed under conventional conditions or manufacturer's recommended conditions. Components used without manufacturer's indication are commercially available conventional products.

[0045] Example 1

[0046] (1) Preparation of nonionic fluorine-modified emulsifier

[0047] a: 20 mmol of isophorone diisocyanate (IPDI) and 0.1 g of bismuth isooctanoate were thoroughly stirred to obtain a uniform mixture. 18 mmol of pentafluoropropanol (30%) dissolved in acetone was added dropwise to the mixture at 55°C through a constant pressure funnel while stirring. The mixture was reacted for 7 hours to obtain an intermediate.

[0048] b: At 60°C, the intermediate obtained in step a was added dropwise to 22 mmol PEG200 via a constant pressure funnel. The mixture was stirred for 8 h and the solvent was removed in vacuo to obtain a nonionic fluorine-modified emulsifier F1.

[0049] (2) In this embodiment, the low-viscosity emulsion ink composition is composed of the following components, calculated in percentage by mass, as shown in Table 1 below:

[0050] Table 1 Formula of low viscosity emulsion ink composition

[0051]

[0052] (3) A method for preparing a low-viscosity emulsion ink, comprising the following steps:

[0053] a: Mix the nano carbon black pigment and the water-soluble wetting and dispersing agent evenly and soak for more than 24 hours to prepare phase A;

[0054] b: Dissolve the alcohol-soluble dye (Runba D45) in an organic solvent (dimethylformamide), add a non-ionic fluorine-modified emulsifier (F1), and stir evenly to prepare phase B;

[0055] c: Add phase A solution and phase B solution, pH adjuster, lubricant, moisturizer, and bactericidal preservative into an emulsifier, emulsify at 2000 rpm for 30 minutes, and then grind in a planetary ball mill at 500 rpm until the particle size in the solution reaches D90 = 150-200 nm, thus obtaining a low-viscosity emulsified ink.

[0056] Example 2

[0057] Different from Example 1, the formula of the medium-low viscosity emulsion ink composition (2) is composed of the following components in percentage by mass, as shown in Table 2 below:

[0058] Table 2 Formula of low viscosity emulsion ink composition

[0059]

[0060]

[0061] The rest of the preparation process is consistent with that in Example 1.

[0062] Example 3

[0063] (1) Preparation of nonionic fluorine-modified emulsifier

[0064] a: 20 mmol of isophorone diisocyanate (IPDI) and 0.6 g of dimethyltin were thoroughly stirred to obtain a uniform mixture. 20 mmol of hexafluoroisopropanol dissolved in acetone to a concentration of 50% was added dropwise to the mixture at 60°C through a constant pressure funnel while stirring. The mixture was reacted for 8 hours to obtain an intermediate.

[0065] b: At 60°C, the intermediate obtained in step a was added dropwise to 20 mmol PEG400 via a constant pressure funnel. The mixture was stirred for 8 h and the solvent was removed in vacuo to obtain a nonionic fluorine-modified emulsifier F2.

[0066] (2) The formula of the low-viscosity emulsion ink composition, in terms of mass percentage, consists of the following components, as shown in Table 3 below:

[0067] Table 3 Formula of low viscosity emulsion ink composition

[0068]

[0069] Its preparation method is consistent with that of Example 1.

[0070] Example 4

[0071] Different from Example 3, the formula of the medium-low viscosity emulsion ink composition (2) is composed of the following components in percentage by mass, as shown in Table 4 below:

[0072] Table 4 Formula of low viscosity emulsion ink composition

[0073]

[0074]

[0075] Its preparation method is consistent with that of Example 1.

[0076] Example 5

[0077] (1) Preparation of nonionic fluorine-modified emulsifier:

[0078] a: 20 mmol of isophorone diisocyanate (IPDI) and 0.36 g of bismuth laurate were thoroughly stirred to obtain a uniform mixture. 22 mmol of perfluorobutyl ethyl alcohol dissolved in 70% acetone was added dropwise to the mixture at 65°C through a constant pressure funnel while stirring. The mixture was reacted for 10 hours to obtain an intermediate.

[0079] b: At 60°C, the intermediate obtained in step a was added dropwise to 18 mmol PEG600 via a constant pressure funnel. The mixture was stirred for 8 h and the solvent was removed in vacuo to obtain a nonionic fluorine-modified emulsifier F3.

[0080] (2) The formula of the medium-low viscosity emulsion ink composition is composed of the following components in percentage by mass, as shown in Table 5 below:

[0081] Table 5 Formula of low viscosity emulsion ink composition

[0082]

[0083] Its preparation method is consistent with that of Example 1.

[0084] Example 6

[0085] Different from Example 5, the formula of the medium-low viscosity emulsion ink composition (2) is composed of the following components in percentage by mass, as shown in Table 6 below:

[0086] Its preparation method is consistent with that of Example 1.

[0087] Table 6 Formula of low viscosity emulsion ink composition

[0088]

[0089] Comparative Example 1

[0090] The difference from Example 1 is that in the formula of the medium-low viscosity emulsified ink composition (2), polyacrylate is used to replace the non-ionic fluorine-modified emulsifier F1, and the other components and preparation method are consistent with Example 1.

[0091] Comparative Example 2

[0092] The difference from Example 1 is that in the formula of the medium-low viscosity emulsified ink composition (2), octylphenol polyoxyethylene ether is used to replace the non-ionic fluorine-modified emulsifier F1, and the other components and preparation method are consistent with Example 1.

[0093] Comparative Example 3

[0094] The difference from Example 1 is that in the formula of (2) the medium-low viscosity emulsified ink composition, Tween 80 is used to replace the non-ionic fluorine-modified emulsifier F1, and the other components and preparation method are the same as those in Example 1.

[0095] Comparative Example 4

[0096] Commercially available Snow direct liquid rollerball pen ink

[0097] Comparative Example 5

[0098] HP HP45 water-based ink replacement on the market

[0099] Performance testing:

[0100] 1. Viscosity test

[0101] Using Brookfield DV2T viscometer, the shear rate is 384s at 25°C. -1 The viscosity value at .

[0102] 2. pH test

[0103] Use Shanghai Yueping pen-type pH meter. At 25°C, immerse the pH meter probe below the ink level, test while shaking, and read the value when it stabilizes.

[0104] 3. Waterproof performance test

[0105] Fill a straight-liquid ballpoint pen with ink and write on A4 paper. After the writing is completely dry, immerse it in room temperature water for 24 hours and observe whether there is any smudging or ink dispersion.

[0106] 4. Thermal storage stability test

[0107] The ink was stored at 60°C for 10 days, and the D90 ink particle size was tested using a laser particle size analyzer. The greater the change in D90, the worse the thermal storage stability.

[0108] 5. Hat removal performance test

[0109] Take 20 ink cartridges with normal initial spraying (the initial spraying refers to the number of sprayed characters being greater than 10, and the handwriting being complete and clear), remove the caps and place them horizontally in a test environment with an ambient temperature of 20-25°C and a relative humidity of 50-60% for 1, 5, 10, 15, and 20 days. Take 4 ink cartridges at each time point. The 4 ink cartridges are qualified if the handwriting is normal for the first spraying, until one fails. The previous time point is the number of days the ink cartridge has been uncapped and sprayed, which is used as an evaluation indicator of the uncapping performance. The longer the number of days the ink cartridge has been uncapped, the better the moisturizing performance of the ink.

[0110] The conventional indicators of the inks of Examples 1-6 and Comparative Examples 1-5 were tested, and the test results are shown in Table 7 below:

[0111] Table 7 Test results of conventional indicators of ink

[0112]

[0113] As can be seen from Table 7, the viscosity of the emulsified inks prepared in Examples 1-6 is significantly lower than that in Comparative Examples 1-3, and the thermal storage stability is significantly better than that in Comparative Examples 1-3, and is similar to that of commercially available Comparative Examples 4-5. The reason for this may be that the nonionic fluorine-modified emulsifier has a unique fluorine structure, and its high surface activity can emulsify the water-oil two-phase molecules more evenly and effectively. In addition, its short fluorocarbon chain structure and low molecular weight polyethylene glycol structure have a lubricating effect between the water-oil two-phase molecules, reducing the intermolecular viscosity. Its high thermal stability can ensure that the emulsion system does not break or agglomerate after thermal storage.

[0114] The waterproof performance of the emulsion ink prepared in Examples 1-6 is better than that of Comparative Example 4. This is because the colorants used in the emulsion inks of Examples 1-6 are nano carbon black pigments and solvent-based dyes, both of which are water-insoluble colorants, so they have good waterproof performance, while the ink in Comparative Example 4 contains water-soluble dyes, so it has poor waterproof performance.

[0115] The decapping performance of the emulsified ink prepared in Examples 1-6 is better than that of Comparative Example 5. This is because the emulsified ink in Examples 1-6 contains an organic solvent that is difficult to volatilize and has good hygroscopicity, so its moisturizing property is stronger than that of ordinary water-based ink on the market, thus ensuring that the cap can be removed for a longer time without drying the nozzle.

[0116] In summary, the emulsified ink of the present invention can be successfully applied to products such as direct liquid ballpoint pens and inkjet printers that require low ink viscosity, further broadening the application range of the emulsified ink.

[0117] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A low-viscosity emulsion ink composition, characterized in that: The invention is composed of the following components by mass percentage: 3-10% of nano carbon black pigment, 5-15% of solvent-based dye, 0.1-5% of wetting and dispersing agent, 1-5% of non-ionic fluorine-modified emulsifier, 0.1-3% of pH regulator, 0.5-5% of lubricant, 5-25% of moisturizing agent, 0.1-1.0% of bactericidal preservative, 10-50% of organic solvent, and the balance is distilled water; The nonionic fluorine-modified emulsifier is a fluorine-containing carbon chain C n F 2n+1 A polyurethane polymer with a structure wherein n≤6 and n is a natural number.

2. The low-viscosity emulsion ink composition according to claim 1, characterized in that The invention is composed of the following components by mass percentage: 5-10% of nano carbon black pigment, 5-10% of solvent-based dye, 0.1-3% of wetting and dispersing agent, 2-5% of non-ionic fluorine-modified emulsifier, 0.1-2% of pH regulator, 0.5-3% of lubricant, 5-20% of moisturizing agent, 0.1-0.5% of bactericidal preservative, 15-50% of organic solvent, and the balance is distilled water.

3. The low-viscosity emulsion ink composition according to claim 1 or 2, characterized in that: The pH value of the low-viscosity emulsion ink composition is in the range of 7-9; at 25°C and a shear rate of 384s -1 The viscosity is 3-10mPa·s; the tension is 25.8-27.3mN / m.

4. The low-viscosity emulsion ink composition according to claim 1, characterized in that The preparation method of the nonionic fluorine-modified emulsifier comprises the following steps: (1) mixing isophorone diisocyanate and a catalyst to prepare a mixed solution; adding dropwise a fluoroalcohol acetone solution to the mixed solution to react and prepare an intermediate; (2) The intermediate obtained in (1) is added dropwise to polyethylene glycol to react, and the solvent is removed in vacuo to obtain a nonionic fluorine-modified emulsifier.

5. The low-viscosity emulsion ink composition according to claim 4, characterized in that: In step (1), the amount of the catalyst added is 2-15 wt% of the amount of isophorone diisocyanate added; The dropping is carried out under normal pressure and the dropping temperature is 55-65°C; The reaction time is 7-10h; The concentration of the acetone solution of the fluoroalcohol is 30-70wt%; The molar ratio of the fluoroalcohol to isophorone diisocyanate is (0.9-1.1):1; The catalyst is one or more of bismuth isooctanoate, bismuth laurate, bisdimethyltin and tetrabutyltin; The fluoroalcohol is one or more of pentafluoropropanol, hexafluoroisopropanol, perfluorobutyl ethyl alcohol and trifluoroethanol.

6. The low-viscosity emulsion ink composition according to claim 4, characterized in that: In step (2), the molar ratio of the polyethylene glycol to isophorone diisocyanate is (0.9-1.1):1; The dropping is carried out under normal pressure and the dropping temperature is 60°C; The reaction time is 8h; The polyethylene glycol is one or more of PEG200, PEG400 and PEG600.

7. The low-viscosity emulsion ink composition according to claim 1 or 2, characterized in that: The solvent-based dye is one or more of Runba D45, Runba D55-V, BASF X51, BASF X55, Wenzhou Aotelai 929 Black and Wenzhou Aotelai 959 Black; The wetting and dispersing agent is one or more of polyoxyethylene ether, alkylphenol oxide and polyacrylate ammonium salt; The pH regulator is one or more of triethanolamine, monoethanolamine and isopropanolamine; The lubricant is one or more of phosphate ester, oleic acid, polyvinyl alcohol and silicone resin; The moisturizing agent is one or more of glycerol, ethylene glycol, hydroxyethyl urea, diethylene glycol and sorbitol; The bactericidal preservative is one or more of methylisothiazolinone, chloroisothiazolinone and methyl parahydroxybenzoate; The organic solvent is one or more of n-methylpyrrolidone, dimethylformamide, dimethylacetamide, ethyl carbitol, dimethyl sulfoxide, ethanol and isopropanol; Preferably, the wetting and dispersing agent is one or more of Dow X405, Dow CF-10, Wanzhao 190 and Digo 760W dispersants.

8. A method for preparing a low-viscosity emulsion ink, characterized in that: The low-viscosity emulsion ink composition according to any one of claims 1 to 7 comprises the following steps: (1) mixing the nano carbon black pigment and the water-soluble wetting dispersant uniformly, and preparing a phase A solution after soaking; (2) dissolving the solvent-based dye in an organic solvent, adding a nonionic fluorine-modified emulsifier, and stirring uniformly to prepare a phase B solution; (3) After mixing the phase A solution, the phase B solution, the pH regulator, the lubricant, the moisturizer, and the bactericidal preservative, the mixture is emulsified and then ball-milled to obtain a low-viscosity emulsified ink.

9. The method for preparing a low-viscosity emulsion ink according to claim 8, wherein: The soaking time is greater than 24 hours; The emulsification speed is 2000-3000 rpm, and the emulsification time is 20-30 min; The ball milling speed is 400-600 rpm; The particle size D90 of the low-viscosity emulsion ink is 150-200 nm.

10. Use of the low-viscosity emulsion ink composition according to any one of claims 1 to 7 in a direct liquid ballpoint pen and an inkjet printer.

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