Water-based nano pigment ink for ink-jet printing and preparation method of water-based nano pigment ink

Abstract

The invention provides water-based nano pigment ink for ink-jet printing and a preparation method of the water-based nano pigment ink. Belongs to the technical field of ink-jet ink. The synergist disclosed by the invention has excellent chemical stability and thermal stability, has no pollution to the ecological environment when being used at a low dosage, and is harmless to human, livestock and aquatic animals. The synergist is added into the ink, so that the ink has excellent performances in the aspects of coloring strength, printing smoothness, rubbing fastness and storage stability, and the technical problems of lower color density, low printing smoothness, low storage stability, low rubbing fastness and easiness in blockage of a spray head of the ink in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of inkjet inks, and in particular to a water-based nano pigment ink for inkjet printing and a preparation method thereof. Background Art

[0002] Inkjet printing is a way of recording text or images by spraying ink droplets directly from a very fine nozzle onto a recording medium to make it adhere. Inkjet printing technology has the characteristics of on-demand design and instant printing, which can meet people's increasing personalized needs. Compared with dye ink, water-based pigment ink has the following advantages: 1. Good versatility, can be directly printed on various substrates such as paper, film, aluminum foil, fabric, leather, etc. It is widely used in digital printing, digital printing, digital imaging, office documents, outdoor inkjet printing, surface decoration and other fields; 2. Simple process, no pollution, no need for complex pre-treatment and post-treatment processes, can be directly inkjet printed on fabrics, and then only simple baking treatment is required; 3. Good light fastness and not easy to decompose.

[0003] The color development, printing smoothness and storage stability of ink are important indicators for evaluating ink. For fabrics, friction fastness is also the focus of the industry. Since the colorant of pigment ink is a solid particle, the pigment particles used for inkjet printing need to reach the nanometer level in order to avoid clogging during printing. In order to make the nanoscale pigment dispersed in water stably for a long time, dispersants are often added to the pigment paste and ink. On the other hand, the formula of water-based pigment ink usually contains pigment paste, water-soluble organic solvent, water-based resin, surfactant, bactericide, pH regulator, viscosity regulator and chelating agent, etc. Existing water-based pigment inks also have the disadvantages of poor compatibility between dispersants and solvents and resins, poor storage stability, low color density of printed images, uneven printed color blocks, and unsmooth printing. In addition, for inkjet printing, improving friction fastness is also the direction of technological innovation in the industry, and a certain amount of curing agent needs to be added to many inks.

[0004] Patent CN109337445A mentions that a digital printing coating ink is added with 5-10% dispersant, which has good washing fastness, simple printing process, and less printing and dyeing wastewater discharge. There is no description of the ink's color development, printing smoothness, and storage stability. Patent CN111021093A provides a cross-linked environmentally friendly textile coating ink. The patent tests the ink's printing smoothness and fastness, but does not characterize the ink's color development. CN110591448 and CN112778837A mention that adding a high molecular weight block polymer dispersant containing pigment affinity groups to the ink formula can improve the ink's printing smoothness and long-term storage stability, but there is no more detailed introduction to other properties of the ink.

[0005] The existing technology cannot fully meet the requirements of digital inkjet printing in actual use, especially the black ink which is used in large quantities in the market, and has high requirements on blackness and friction fastness, so it is necessary to improve it. Summary of the invention

[0006] The object of the present invention is to provide an aqueous nano-pigment ink for inkjet printing and a preparation method thereof, so as to solve the technical problems in the prior art that the ink has low color density, low printing fluency and storage stability, low friction fastness and easy clogging of the nozzle.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a water-based nano pigment ink for inkjet printing, which is composed of the following components in parts by weight: 10 to 40 parts of pigment paste, 0.5 to 20 parts of synergist, 5 to 35 parts of water-soluble organic solvent, 1 to 30 parts of water-based resin, 0.1 to 10 parts of surfactant, 0.05 to 1 part of bactericide, and 10 to 80 parts of water;

[0009] The structure of the synergist is as follows:

[0010]

[0011] Wherein, n=0-10, n is an integer, R1-R7 are independently H, C1-C 18 Alkyl and C1~C 18 One of the alkoxy groups;

[0012] Q1-Q5 independently include one of H, -OM, -SM, -COOM, -PO3M2 and -SO3M, wherein at least one of Q1-Q5 is -COOM, -PO3M2 or -SO3M;

[0013] M includes H, monovalent metal cations, equivalents of multivalent cations, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcoholamine.

[0014] Further, the pigment paste includes a paste prepared using a dispersant and a grinding resin or a self-dispersing paste prepared by a surface modification method;

[0015] The pigment includes carbon black.

[0016] Furthermore, the water-soluble organic solvent includes one or more of polyols, polyol alkyl ethers and nitrogen-containing compounds.

[0017] Furthermore, the water-based resin includes one or more of acrylic resin, fluorene resin, polyurethane resin, polyolefin resin, rosin-modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer and ethylene-vinyl acetate resin.

[0018] Furthermore, the surfactant includes one or more of acetylenic glycols, silicones and fluorine-containing surfactants.

[0019] Furthermore, the fungicide includes one or more of sodium benzoate, sodium pentachlorophenol, sodium pyrithione, sodium sorbate, sodium dehydroacetate, PROXEL CRL, BND, GXL, XL-2 and TN.

[0020] The present invention also provides a method for preparing aqueous nano pigment ink for inkjet printing, comprising the following steps:

[0021] Step 1): water, a synergist, a water-soluble organic solvent, a surfactant and a bactericide are mixed, and then a water-based resin and a pigment paste are added in sequence and stirred to obtain a rough ink;

[0022] Step 2) aging, filtering and defoaming the crude ink to obtain water-based nano-pigment ink for inkjet printing.

[0023] Furthermore, in step 1), the mixing is carried out under stirring, and the stirring time is 5 to 20 minutes;

[0024] When adding water-based resin and pigment paste, they need to be stirred separately, and the stirring time is 20 to 80 minutes.

[0025] Furthermore, in step 2), the aging temperature is 16 to 35° C., and the aging time is 15 to 36 hours.

[0026] Beneficial effects of the present invention:

[0027] The present invention adds a synergist with good high temperature stability and chemical stability to the ink, which is well compatible with various components in the ink, and the prepared ink prints smoothly and can be stably stored for a long time. The synergist can form hydrogen bonds with the pigment, has a dispersing and stabilizing effect on the pigment, can inhibit the diffusion of the ink into the substrate, effectively increase the degree of ink interception on the surface of the substrate, and improve the color development. Especially for digital printing, since the fabric does not need to be pre-treated by dipping, roller coating, spraying or inkjet coating and drying during printing, the process is simplified, thereby improving the printing efficiency, and the fabric can be prevented from feeling worse and hardening after printing. The water-based nano-pigment ink for inkjet printing provided by the present invention is safe and environmentally friendly, can reduce the erosion of the nozzle, and extend the service life of the nozzle. DETAILED DESCRIPTION

[0028] The present invention provides a water-based nano pigment ink for inkjet printing, which is composed of the following components in parts by weight: 10 to 40 parts of pigment paste, 0.5 to 20 parts of synergist, 5 to 35 parts of water-soluble organic solvent, 1 to 30 parts of water-based resin, 0.1 to 10 parts of surfactant, 0.05 to 1 part of bactericide, and 10 to 80 parts of water;

[0029] The structure of the synergist is as follows:

[0030]

[0031] Wherein, n=0-10, n is an integer, R1-R7 independently include H, C1-C 18 Alkyl and C1~C 18 One of the alkoxy groups;

[0032] Q1-Q5 independently include one of H, -OM, -SM, -COOM, -PO3M2 and -SO3M, wherein at least one of Q1-Q5 is -COOM, -PO3M2 or -SO3M;

[0033] M includes H, monovalent metal cations, equivalents of multivalent cations, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcoholamine.

[0034] In the present invention, the pigment paste is preferably 15 to 35 parts, more preferably 20 to 30 parts, calculated by weight; the synergist is preferably 1 to 15 parts, more preferably 2 to 10 parts; the water-soluble organic solvent is preferably 10 to 30 parts, more preferably 15 to 25 parts; the aqueous resin is preferably 5 to 25 parts, more preferably 10 to 20 parts; the surfactant is preferably 0.3 to 5 parts, more preferably 0.5 to 3 parts; the bactericide is preferably 0.1 to 0.8 parts, more preferably 0.2 to 0.5 parts; the water is preferably 15 to 60 parts, more preferably 20 to 50 parts.

[0035] In the structure of the synergist of the present invention, n is preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and more preferably 1, 2, 3, 4; R1 to R7 are independently preferably H, C1 to C 12 and C1~C 12 alkoxy, more preferably H, C1-C6 and C1-C6 alkoxy; Q1-Q5 are independently preferably -COOM, -PO3M2 or -SO3M, more preferably -PO3M2; M is preferably H, monovalent metal cation, Ca 2+ Mg2+ , Ba 2+ 、Al 3+ NH4 + , methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine salt or triisopropanolamine, more preferably H, monovalent metal cations, Ca 2+ Mg 2+ , Ba 2+ 、Al 3+ or NH4 + .

[0036] In the present invention, the pH value of the synergist is 8-10, preferably 8.5-9.5, and more preferably 9.

[0037] In the present invention, the pigment paste includes a paste prepared using a dispersant and a grinding resin or a self-dispersible paste prepared by a surface modification method, preferably a self-dispersible paste prepared by a surface modification method;

[0038] The pigment includes carbon black.

[0039] In the present invention, the carbon black is pigment black 7, preferably one or more of channel black, furnace black and lamp black.

[0040] In the present invention, the water-soluble organic solvent includes one or more of polyols, polyol alkyl ethers and nitrogen-containing compounds, preferably polyols, polyol alkyl ethers and nitrogen-containing compounds.

[0041] In the present invention, the polyol includes ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, 3-methyl-1,3,5-pentanetriol or trimethylolpropane, preferably ethylene glycol, diethylene glycol, polyethylene glycol or propylene glycol, further preferably diethylene glycol, polyethylene glycol or propylene glycol. The polyol in the organic solvent plays the role of moisturizing and adjusting viscosity. It can keep the formula stable in the ink, reduce water volatilization, ensure smooth spraying and prevent clogging.

[0042] In the present invention, the polyol ether includes ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, triethylene glycol monoisobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether or triethylene glycol monobutyl ether, preferably ethylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether or triethylene glycol monobutyl ether. The polyol ethers are preferably ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether or triethylene glycol monoisobutyl ether, and are further preferably ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether or diethylene glycol monoethyl ether. The polyol ethers can increase the permeability of the ink in the substrate, which is beneficial to the wetting and spreading of the ink on the surface of the substrate.

[0043] In the present invention, the nitrogen-containing compound includes formamide, N-methylformamide, N,N-dimethylformamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethylpyrrolidone, 1,3-dimethylimidazolidinone or ε-caprolactam, preferably formamide, N-methylformamide, N,N-dimethylformamide, 2-pyrrolidone or N-methyl-2-pyrrolidone, further preferably formamide, N-methylformamide or N,N-dimethylformamide. The nitrogen-containing compound can improve the compatibility of the ink and ensure the smoothness of printing.

[0044] In the present invention, the water-based resin includes one or more of acrylic resin, fluorene resin, polyurethane resin, polyolefin resin, rosin-modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer and ethylene-vinyl acetate resin, preferably one or more of acrylic resin, fluorene resin, polyurethane resin, polyolefin resin and rosin-modified resin, further preferably one or more of acrylic resin, fluorene resin and polyurethane resin, more preferably polyurethane resin.

[0045] In the present invention, the surfactant includes one or more of acetylenic diols, silicones and fluorine-containing surfactants, preferably acetylenic diols or silicones, and more preferably acetylenic diols;

[0046] In the present invention, the acetylene glycol surfactant includes Surfynol 104, Surfynol 104E, Surfynol 104H, Surfynol 104A, Surfynol 104B, Surfynol 104DPM, Surfynol 104PA, Surfynol 104PG-50, Surfynol 104S, Surfynol 420, Surfynol 440, Surfynol 465 or Surfynol 485, preferably Surfynol 104, Surfynol 104E, Surfynol 104H, Surfynol 104A or Surfynol 104B, and more preferably Surfynol 104, Surfynol 104E or Surfynol 104H.

[0047] In the present invention, the silicone surfactant includes BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346 or BYK-348, preferably BYK-306, BYK-307, BYK-333 or BYK-341, and more preferably BYK-306 or BYK-307;

[0048] The fluorinated surfactant is preferably BYK-340;

[0049] The fungicide includes one or more of sodium benzoate, sodium pentachlorophenol, sodium pyrithione, sodium sorbate, sodium dehydroacetate, PROXEL CRL, BND, GXL, XL-2 and TN, preferably one or more of sodium pyrithione, sodium sorbate, sodium dehydroacetate, PROXEL CRL and BND, further preferably one or more of sodium dehydroacetate, PROXEL CRL and BND, and more preferably PROXEL CRL.

[0050] In the present invention, the water includes deionized water or water irradiated or sterilized by ultraviolet rays, preferably deionized water.

[0051] The present invention also provides a method for preparing aqueous nano pigment ink for inkjet printing, comprising the following steps:

[0052] Step 1): water, a synergist, a water-soluble organic solvent, a surfactant and a bactericide are mixed, and then a water-based resin and a pigment paste are added in sequence and stirred to obtain a rough ink;

[0053] Step 2) aging, filtering and defoaming the crude ink to obtain water-based nano-pigment ink for inkjet printing.

[0054] In the present invention, in step 1), the mixing is carried out under stirring, and the stirring time is 5 to 20 minutes, preferably 10 to 15 minutes, and more preferably 12 minutes;

[0055] When the water-based resin and the pigment paste are added, they need to be stirred separately, and the stirring time is independently 20 to 80 minutes, preferably 30 to 50 minutes, and more preferably 40 minutes.

[0056] In the present invention, in step 2), the aging temperature is 16 to 35°C, preferably 20 to 30°C, and more preferably 25°C; the aging time is 15 to 36h, preferably 20 to 30°C, and more preferably 25°C.

[0057] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0058] The present invention provides a synergist, the structure of the synergist is as follows:

[0059]

[0060] Wherein, n=0-10, n is an integer, R1-R7 are independently H, C1-C 18 Alkyl and C1~C 18 One of the alkoxy groups;

[0061] Q1-Q5 independently include one of H, -OM, -SM, -COOM, -PO3M2 and -SO3M, wherein at least one of Q1-Q5 is -COOM, -PO3M2 or -SO3M;

[0062] M includes H, monovalent metal cations, equivalents of multivalent cations, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcoholamine.

[0063] In the present invention, the ink preferably comprises the following components:

[0064] Pigment paste: self-dispersible carbon black paste, 15wt%, homemade;

[0065] ZXJ: synergist, homemade;

[0066] BYK-190: dispersant;

[0067] GLY: glycerol;

[0068] 1,2-HD: 1,2-hexanediol;

[0069] TEGmBE: triethylene glycol monobutyl ether;

[0070] NMP: N-methylpyrrolidone;

[0071] 101: Water-based resin, homemade;

[0072] 104E: Surfynol 104E, surfactant;

[0073] XL-2: Proxel XL-2, fungicide.

[0074] Example 1

[0075] 15 mL of water and 6.1 g of ethylenediamine were mixed and dissolved, and phosphorous acid was added at 30° C. to react. The reaction was exothermic. When the temperature dropped to 40° C., 33.3 g of formaldehyde solution was added dropwise thereto. The temperature was then raised to 100° C. to react for 2 h, and then cooled to room temperature to obtain an aqueous solution of ethylenediaminetetramethylenephosphonic acid (EDTMP). The pH of the aqueous solution of ethylenediaminetetramethylenephosphonic acid was adjusted to 9 using a 30% mass concentration of sodium hydroxide aqueous solution, and water was added to adjust to obtain a 30 wt % EDTMPS solution, which was recorded as enhancer A.

[0076] The structural formula of ethylenediaminetetramethylenephosphonic acid is:

[0077] Example 2

[0078] Different from Example 1, in this example, a potassium hydroxide aqueous solution with a mass concentration of 30% is used to adjust the pH of the ethylenediaminetetramethylenephosphonic acid aqueous solution, and finally an EDTMPP solution is obtained, which is recorded as synergist B.

[0079] Example 3

[0080] Different from Example 1, in this example, an ammonia solution with a mass concentration of 25% is used to adjust the pH of the ethylenediaminetetramethylenephosphonic acid aqueous solution, and finally an EDTMPA solution is obtained, which is recorded as synergist C.

[0081] Example 4

[0082] Different from Example 1, in this example, a triethanolamine aqueous solution with a mass concentration of 50% is used to adjust the pH of the ethylenediaminetetramethylenephosphonic acid aqueous solution, and finally an EDTMPTE solution is obtained, which is recorded as synergist D.

[0083] Example 5

[0084] Different from Example 1, in this example, a triisopropanolamine aqueous solution with a mass concentration of 50% is used to adjust the pH of the ethylenediaminetetramethylenephosphonic acid aqueous solution, and finally an EDTMPTIP solution is obtained, which is recorded as synergist E.

[0085] Example 6

[0086] Different from Example 1, in this example, the amine aqueous solution is composed of 50 mL of water and 10.4 g of diethylenetriamine, and the amount of phosphorous acid added is 41.7 g to obtain a diethylenetriamine penta (methylenephosphonic acid) aqueous solution. The pH of the diethylenetriamine penta (methylenephosphonic acid) aqueous solution is adjusted to 9 using a 30% mass concentration of sodium hydroxide aqueous solution, and water is added to adjust, and finally a DTPMPS solution is obtained, which is recorded as synergist F.

[0087] The structural formula of diethylenetriaminepenta(methylenephosphonic acid) is:

[0088] Example 7

[0089] Different from Example 6, in this example, a potassium hydroxide aqueous solution with a mass concentration of 30% is used to adjust the pH of the diethylenetriaminepenta(methylenephosphonic acid) aqueous solution, and finally a DTPMPP solution is obtained, which is recorded as synergist G.

[0090] Example 8

[0091] Different from Example 6, in this example, an aqueous ammonia solution with a mass concentration of 25% is used to adjust the pH of the diethylenetriaminepenta(methylenephosphonic acid) aqueous solution, and finally a DTPMPA solution is obtained, which is recorded as synergist H.

[0092] Example 9

[0093] Different from Example 6, in this example, a triethanolamine aqueous solution with a mass concentration of 50% is used to adjust the pH of the diethylenetriamine penta(methylenephosphonic acid) aqueous solution, and finally a DTPMPTE solution is obtained, which is recorded as synergist I.

[0094] Example 10

[0095] Different from Example 6, in this example, a triisopropanolamine aqueous solution with a mass concentration of 50% was used to adjust the pH of the diethylenetriaminepenta(methylenephosphonic acid) aqueous solution, and finally a DTPMPTIP solution was obtained, which was recorded as synergist J.

[0096] Embodiment 11

[0097] 28.37g of monochloroacetic acid was added to the reaction bottle, and 22mL of distilled water was added and stirred to dissolve. 30g of 40wt% NaOH solution was added dropwise at 15℃, and the addition was completed in 1.5h; then 5.16g of diethylenetriamine was added dropwise under stirring, and the temperature was controlled at 20℃ during the addition; then 12g of 40% NaOH aqueous solution was added dropwise, and the reaction was carried out at 40℃ for 11h; the reaction solution was cooled to 8℃. 26mL of concentrated hydrochloric acid was added dropwise under stirring, the pH value was adjusted to 1.6, and it was left overnight. The crystals were filtered out, and the crystals were washed with 40mL of ice water, and vacuum dried to obtain about 13g of crude product. After decolorization and filtration with distilled water, a colorless transparent liquid was obtained, namely diethylenetriaminepentaacetic acid (DTPA) solution. The pH of the diethylenetriaminepentaacetic acid aqueous solution was adjusted to 9 with a mass concentration of 30% sodium hydroxide aqueous solution, and water was added to adjust, and finally a DTPAS solution with a mass concentration of 30% was obtained, which was recorded as synergist K.

[0098] The structural formula of diethylenetriaminepentaacetic acid is:

[0099] Example 12

[0100] Different from Example 11, in this example, a potassium hydroxide aqueous solution with a mass concentration of 30% is used to adjust the pH of the diethylenetriaminepentaacetic acid aqueous solution, and finally a DTPAP solution with a mass concentration of 30% is obtained, which is recorded as synergist L.

[0101] Embodiment 13

[0102] Different from Example 1, in this example, an ammonia solution with a mass concentration of 25% is used to adjust the pH of the diethylenetriaminepentaacetic acid aqueous solution, and finally a DTPAA solution with a mass concentration of 30% is obtained, which is recorded as synergist M.

[0103] Embodiment 14

[0104] Different from Example 1, in this example, a triethanolamine aqueous solution with a mass concentration of 50% is used to adjust the pH of the diethylenetriaminepentaacetic acid aqueous solution, and finally a DTPATE solution with a mass concentration of 30% is obtained, which is recorded as synergist N.

[0105] Embodiment 15

[0106] Different from Example 1, in this example, a triisopropanolamine aqueous solution with a mass concentration of 50% is used to adjust the pH of the diethylenetriaminepentaacetic acid aqueous solution, and finally a DTPATIP solution with a mass concentration of 30% is obtained, which is recorded as synergist O.

[0107] Example 16

[0108] Add 105g of β-hydroxyethylethylenediamine to a three-necked flask equipped with a stirrer, a thermometer, a dropping funnel and an ice-salt bath, and drip 100g of concentrated sulfuric acid under stirring. The temperature is adjusted at 10°C with an ice-salt bath during the dripping process. After the dripping is completed, remove the ice-salt bath, add toluene, and remove the water in the reaction flask by vacuum distillation to obtain the intermediate ethylenediamine ethanol sulfate. Cool to room temperature, add sodium carbonate solution, until no gas is released, add a saturated solution of sodium sulfite (151g) for sulfonation, reflux reaction at 110°C for 30 hours, then vacuum distill to remove part of the water, cool to 92°C, hot filter, remove sodium sulfate and sodium sulfite crystals, and obtain the crude product of ethylenediamine ethyl sulfonic acid sodium salt. After cooling crystallization, acidification, and recrystallization purification, the fine product of ethylenediamine ethyl sulfonic acid is obtained. The pH of ethylenediamine ethyl sulfonic acid was adjusted to 9 using a sodium hydroxide aqueous solution with a mass concentration of 30%, and water was added to adjust, and finally a sodium salt solution of ethylenediamine ethyl sulfonic acid with a mass concentration of 30% was obtained, which was recorded as synergist P.

[0109] The structural formula of ethylenediamine ethyl sulfonic acid is:

[0110] Embodiment 17

[0111] Different from Example 16, in this example, a potassium hydroxide aqueous solution with a mass concentration of 30% is used to adjust the pH of ethylenediamine ethyl sulfonic acid to 9, and water is added to adjust, and finally an ethylenediamine ethyl sulfonic acid potassium salt solution is obtained, which is recorded as enhancer Q.

[0112] Embodiment 18

[0113] Different from Example 16, in this example, an aqueous ammonia solution with a mass concentration of 25% is used to adjust the pH of ethylenediamine ethyl sulfonic acid to 9, and water is added to adjust, and finally an ethylenediamine ethyl sulfonic acid ammonium salt solution is obtained, which is recorded as enhancer R.

[0114] Embodiment 19

[0115] Different from Example 16, in this example, a 50% mass concentration of triethanolamine aqueous solution is used to adjust the pH of the diethylenetriamine penta (methylenephosphonic acid) aqueous solution to 9, and water is added to adjust, and finally a triethanolamine salt solution of ethylenediamine ethylsulfonic acid is obtained, which is recorded as enhancer S.

[0116] Embodiment 20

[0117] Different from Example 16, in this example, a triisopropanolamine aqueous solution with a mass concentration of 50% is used to adjust the pH of ethylenediamine ethyl sulfonic acid to 9, and water is added to adjust, and finally a triisopropanolamine salt solution of ethylenediamine ethyl sulfonic acid is obtained, which is recorded as enhancer T.

[0118] Embodiment 21

[0119] Take 3 parts of enhancer A, 10 parts of glycerol, 2 parts of 1,2-hexanediol, 3 parts of triethylene glycol monobutyl ether, 5 parts of N-methylpyrrolidone, 1 part of Surfynol 104E, 0.2 parts of Proxel XL-2 and 40.8 parts of water, mix them, then add 15 parts of 101 resin and stir for 30 minutes, then add 20 parts of self-dispersible carbon black slurry and continue stirring for 60 minutes to obtain a rough ink; the obtained rough ink is aged at 25°C for 24 hours, and then filtered and defoamed in sequence to obtain a water-based nano pigment ink for inkjet printing.

[0120] Embodiments 22 to 40

[0121] Different from Example 21, in Examples 22 to 40, the synergist A is replaced by synergists B to T respectively.

[0122] Comparative Example 1

[0123] The difference from Example 21 is that the synergist A is replaced by the dispersant BYK-190.

[0124] Embodiment 41

[0125] Take 5 parts of enhancer A, 10 parts of glycerol, 2 parts of 1,2-hexanediol, 3 parts of triethylene glycol monobutyl ether, 5 parts of N-methylpyrrolidone, 1 part of Surfynol 104E, 0.2 parts of Proxel XL-2 and 20.8 parts of water, mix them, then add 20 parts of 101 resin and stir for 30 minutes, then add 33 parts of self-dispersed carbon black slurry and continue stirring for 60 minutes to obtain a crude ink; the obtained crude ink is aged at 25°C for 24 hours, and then filtered and defoamed in sequence to obtain a water-based nano pigment ink for inkjet printing.

[0126] Embodiments 42 to 60

[0127] Different from Example 41, in Examples 42 to 60, the synergist A is replaced with synergists B to T respectively.

[0128] Comparative Example 2

[0129] The difference from Example 41 is that the synergist A is replaced by the dispersant BYK-190.

[0130] The inks obtained in Examples 21 to 60 and Comparative Examples 1 to 2 were tested, and the testing method was as follows:

[0131] 1) Color development evaluation

[0132] The inks obtained in Examples 21 to 60 and Comparative Examples 1 to 2 were used to print solid color blocks of 180 mm*270 mm on ordinary printing paper, and the color density OD of the color block was measured using a spectrophotometer (purchased from X-Rite (Shanghai) Color Technology Co., Ltd.).

[0133] The evaluation criteria are as follows:

[0134] A: OD value is above 1.40;

[0135] B: OD value is above 1.30 and less than 1.40;

[0136] C: OD value is less than 1.30.

[0137] 2) Printing Fluency

[0138] The inks obtained in Examples 21 to 60 and Comparative Examples 1 to 2 were used to print solid color blocks of 180 mm*270 mm on ordinary printing paper, and 15 sheets were printed continuously. Then, test strips were printed and the test results were observed.

[0139] The evaluation criteria are as follows:

[0140] A: Ink breaks are less than 3;

[0141] B: ink breaks are greater than 3 and less than 10;

[0142] C: There are more than 10 ink breaks or the printed lines are disordered.

[0143] 3) Evaluation of rubbing fastness

[0144] The inks obtained in Examples 21 to 60 and Comparative Examples 1 to 2 were respectively printed on fine cotton cloth, baked at 170° C. for 60 seconds, cooled to room temperature, and tested according to the method of “GB / T 3920-2008 Textiles - Color Fastness - Tests for Color Fastness to Rubbing”.

[0145] Evaluation criteria:

[0146] A: The friction fastness is above level 3;

[0147] B: Friction fastness is above level 2;

[0148] C: The rubbing fastness is below level 2.

[0149] 4) Ink storage stability

[0150] The temperature of the inks obtained in Examples 21 to 60 and Comparative Examples 1 to 2 was adjusted to 25° C., and the static viscosity was measured at a shear rate of 50 (l / s) using a DV-2T viscometer produced by Bruker.

[0151] Evaluation criteria:

[0152] A: Viscosity change is less than 10%;

[0153] B: Viscosity change is greater than 10% but not more than 20%;

[0154] C: Viscosity change is greater than 20%.

[0155] The test results of various properties of the inks obtained in the examples and comparative examples are shown in Table 1 and Table 2.

[0156] Table 1 Test results of various properties of inks obtained in Examples 21 to 40 and Comparative Example 1

[0157]

[0158]

[0159] Table 2 Test results of various properties of inks obtained in Examples 41 to 60 and Comparative Example 2

[0160]

[0161]

[0162] As can be seen from Table 1 and Table 2, the water-based pigment ink provided by the present invention performs well in terms of coloring strength, printing smoothness, rubbing fastness and storage stability. In Comparative Examples 1 and 2, dispersant BYK-190 is used instead of synergist, which is inferior to the embodiments of the present invention in terms of color development, printing smoothness and wet rubbing fastness. In particular, after increasing the ratio of pigment paste in the ink, although the color development of the ink in Comparative Example 2 is improved, its printing smoothness, rubbing fastness and storage stability are all reduced.

[0163] As can be seen from the above embodiments, the present invention provides a water-based nano pigment ink for inkjet printing and a preparation method thereof. The synergist of the present invention can dissociate into multiple pairs of anions and cations in water, can form a complex with the pigment through hydrogen bonds, and has a dispersing and stabilizing effect on the pigment. It can inhibit the diffusion of ink into the interior of the substrate, effectively reduce the penetration of the ink into the substrate, and improve the color development. The complex formed by the synergist and the pigment has a good curing effect on the substrate and can enhance the friction resistance of the recorded object. The synergist has good compatibility with other components in the ink, can inhibit the growth of microorganisms in the ink, and is conducive to the long-term stable storage of the ink. In addition, the synergist of the present invention has excellent chemical stability and thermal stability, and is not easy to decompose in strong acid and alkali media. Its toxicity is very small, has no carcinogenic and teratogenic effects, and is harmless to humans, livestock and aquatic animals when used in low doses, and does not pollute the ecological environment. The water-based pigment ink of the present invention is excellent in coloring strength, printing fluency, rubbing fastness and storage stability, and solves the technical problems of low color density, low printing fluency and storage stability, low rubbing fastness and easy clogging of the nozzle in the prior art.

[0164] The above is only 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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A water-based nano-pigment ink for inkjet printing, characterized in that: The invention is composed of the following components in parts by weight: 10 to 40 parts of pigment paste, 0.5 to 20 parts of synergist, 5 to 35 parts of water-soluble organic solvent, 1 to 30 parts of water-based resin, 0.1 to 10 parts of surfactant, 0.05 to 1 part of bactericide, and 10 to 80 parts of water; The structure of the synergist is as follows: Wherein, n=0-10, n is an integer, R1-R7 are independently H, C1-C 18 Alkyl and C1~C 18 One of the alkoxy groups; Q1-Q5 independently include one of H, -OM, -SM, -COOM, -PO3M2 and -SO3M, wherein at least one of Q1-Q5 is -COOM, -PO3M2 or -SO3M; M includes H, monovalent metal cations, equivalents of multivalent cations, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcoholamine.

2. The aqueous nano pigment ink for inkjet printing according to claim 1, characterized in that: The pigment paste includes a paste prepared using a dispersant and a grinding resin or a self-dispersing paste prepared by a surface modification method; The pigment includes carbon black.

3. A water-based nano pigment ink for inkjet printing according to claim 1 or 2, characterized in that: The water-soluble organic solvent includes one or more of polyols, polyol alkyl ethers and nitrogen-containing compounds.

4. The aqueous nano pigment ink for inkjet printing according to claim 3, characterized in that: The water-based resin includes one or more of acrylic resin, fluorene resin, polyurethane resin, polyolefin resin, rosin-modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer and ethylene-vinyl acetate resin.

5. The aqueous nano pigment ink for inkjet printing according to claim 1, 2 or 4, characterized in that: The surfactant includes one or more of acetylenic glycols, silicones and fluorine-containing surfactants.

6. The aqueous nano pigment ink for inkjet printing according to claim 5, characterized in that: The bactericide includes one or more of sodium benzoate, sodium pentachlorophenol, sodium pyrithione, sodium sorbate, sodium dehydroacetate, PROXEL CRL, BND, GXL, XL-2 and TN.

7. The method for preparing a water-based nano-pigment ink for inkjet printing according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1): water, a synergist, a water-soluble organic solvent, a surfactant and a bactericide are mixed, and then a water-based resin and a pigment paste are added in sequence and stirred to obtain a rough ink; Step 2) aging, filtering and defoaming the crude ink to obtain water-based nano-pigment ink for inkjet printing.

8. The method for preparing a water-based nano-pigment ink for inkjet printing according to claim 7, characterized in that: In step 1), the mixing is carried out under stirring, and the stirring time is 5 to 20 minutes; When adding water-based resin and pigment paste, they need to be stirred separately, and the stirring time is 20 to 80 minutes.

9. The method for preparing aqueous nano pigment ink for inkjet printing according to claim 8, characterized in that: In step 2), the aging temperature is 16 to 35° C., and the aging time is 15 to 36 hours.

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