Water-based nano pigment ink for inkjet printing and preparation method thereof

Abstract

The present application provides a kind of water-based nano pigment ink for ink-jet printing and its preparation method.Belongs to ink-jet ink technical field.The synergist of the present application has excellent chemical stability and thermal stability, and low-dose use has no pollution to ecological environment, and is harmless to human and livestock, aquatic animals. Adding the above synergist in the ink can make the ink excellent in coloring intensity, printing fluency, rubbing fastness and storage stability, solve the technical problems of low color density, low printing fluency and storage stability, low rubbing fastness and easy to block the nozzle in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of inkjet ink technology, and particularly relates to a water-based nano pigment ink for inkjet printing and a preparation method thereof. BACKGROUND

[0002] Inkjet printing is a recording method that ink droplets are directly sprayed from very fine nozzles onto a recording medium, and then the ink droplets are attached to obtain text or images. Inkjet printing technology has the characteristics of on-demand design and instant printing, and can meet the increasing personalized needs of people. Compared with dye ink, water-based pigment ink has the following advantages: 1. Good versatility, which can be directly printed on various paper, film, aluminum foil, fabric, leather and other substrates, and is widely used in digital printing, digital printing, digital image, office documents, outdoor spray drawing, surface decoration and other fields; 2. Simple process, no pollution, no need for complex pretreatment and post-treatment process, can directly inkjet printing on fabric, and then only needs simple baking treatment; 3. Good light fastness and not easy to decompose.

[0003] The color developing property, printing fluency and storage stability of ink are important indicators for evaluating the ink. For fabrics, the rubbing 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 to prevent clogging during printing. In order to make the nano-scale pigment stably dispersed in water for a long time, a dispersing agent is often added to the pigment paste and ink. On the other hand, the water-based pigment ink formula usually contains pigment paste, water-soluble organic solvent, water-based resin, surfactant, bactericide, pH adjuster, viscosity adjuster and chelating agent, etc. The existing water-based pigment ink also has the disadvantages of poor compatibility of dispersing agent with solvent and resin, poor storage stability, low color density of printed image, uneven printing color block, and poor printing fluency. In addition, for inkjet printing, improving the rubbing 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 5-10% of a dispersing agent is added to a digital printing coating ink, which has good washing fastness, simple printing process and less printing wastewater discharge. The color developing property, printing fluency and storage stability of the ink are not mentioned. Patent CN111021093A provides a cross-linked environmentally friendly textile coating ink. The printing fluency and fastness of the ink are tested in the patent, but the color developing property of the ink is not characterized. CN110591448 and CN112778837A mention that a high molecular weight block polymer dispersant containing a pigment affinity group is added to the ink formula, which can improve the printing fluency and long-term storage stability of the ink, but the other properties of the ink are not introduced in more detail.

[0005] The prior art cannot fully meet the requirements of digital inkjet printing in practical use, especially the black ink which has a large amount in the market, and the blackness and rubbing fastness are required to be higher, so it is necessary to improve. SUMMARY

[0006] The present application aims to provide a water-based nano pigment ink for inkjet printing and a preparation method thereof, which is used to solve the technical problems of low color density, low printing fluency and storage stability, low rubbing fastness and easy clogging of the inkjet head in the prior art.

[0007] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0008] The present application provides a water-based nano pigment ink for inkjet printing, which is composed of components including the following mass fractions: pigment color paste 10-40 parts, synergist 0.5-20 parts, water-soluble organic solvent 5-35 parts, water-based resin 1-30 parts, surfactant 0.1-10 parts, bactericide 0.05-1 part, and water 10-80 parts.

[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 alkoxy;

[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 cation, equivalent of polyvalent cation, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcohol amine.

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

[0015] The pigment includes carbon black.

[0016] Further, the water-soluble organic solvent includes one or several of polyhydric alcohol, polyhydric alcohol alkyl ether and nitrogen-containing compound.

[0017] Further, the water-based resin comprises 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] Further, the surfactant comprises one or more of acetylene diol, organosilicon and fluorine-containing surfactant.

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

[0020] The application also provides a preparation method of the water-based nano pigment ink for inkjet printing, comprising the following steps:

[0021] Step 1): mixing water, synergist, water-soluble organic solvent, surfactant and bactericide, and then sequentially adding water-based resin and pigment color paste and stirring to obtain crude ink;

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

[0023] Further, in step 1), the mixing is carried out under stirring, and the stirring time is 5-20 min.

[0024] The water-based resin and the pigment color paste need to be added respectively under stirring, and the stirring time is independently 20-80 min.

[0025] Further, in step 2), the aging temperature is 16-35℃, and the aging time is 15-36 h.

[0026] The application has the following beneficial effects:

[0027] The application adds the synergist with good high-temperature stability and chemical stability into the ink, which is well compatible with various components in the ink, the prepared ink is smooth in printing and can be stored stably for a long time. The synergist can form hydrogen bond with the pigment, has dispersion and stabilization effects on the pigment, can inhibit the diffusion of the ink into the substrate, effectively increases the retention degree of the ink on the substrate surface and improves the color development. Especially for digital printing, since the fabric does not need to be pre-processed by immersion coating, roller coating, spraying or inkjet coating and drying method, the process is simplified, the printing efficiency is improved, and the fabric after printing can avoid poor hand feeling and hardness. DETAILED DESCRIPTION

[0028] The present application provides a kind of water-based nano pigment ink for ink-jet printing, by comprising the components of the following mass fraction: pigment paste 10-40 parts, synergist 0.5-20 parts, water-soluble organic solvent 5-35 parts, water-based resin 1-30 parts, surfactant 0.1-10 parts, bactericide 0.05-1 part, water 10-80 parts;

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

[0030]

[0031] Wherein, n=0-10, n is integer, R1-R7 independently include one of H, C1-C 18 Alkyl and C1-C 18 Alkoxy;

[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 cation, equivalent of polyvalent cation, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcohol amine.

[0034] In the present application, the pigment paste is preferably 15-35 parts, further preferably 20-30 parts, by mass fraction; the synergist is preferably 1-15 parts, further preferably 2-10 parts; the water-soluble organic solvent is preferably 10-30 parts, further preferably 15-25 parts; the water-based resin is preferably 5-25 parts, further preferably 10-20 parts; the surfactant is preferably 0.3-5 parts, further preferably 0.5-3 parts; the bactericide is preferably 0.1-0.8 parts, further preferably 0.2-0.5 parts; the water is preferably 15-60 parts, further preferably 20-50 parts.

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

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

[0037] In the present application, 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, preferably a self-dispersing paste prepared by a surface modification method;

[0038] The pigment includes carbon black.

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

[0040] In the present application, the water-soluble organic solvent includes one or more of a polyol, a polyol alkyl ether and a nitrogen-containing compound, preferably a polyol, a polyol alkyl ether and a nitrogen-containing compound.

[0041] In the present application, the polyol includes ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 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 a role of moisturizing and adjusting viscosity, can maintain formula stability in the ink, reduce water evaporation, ensure smooth ejection, and prevent blockage.

[0042] In the present application, 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, 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, further preferably ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether or diethylene glycol monoethyl ether. The polyol ether can increase the permeability of the ink in the substrate, and is beneficial to the wetting and spreading of the ink on the surface of the substrate.

[0043] In the present application, the nitrogen-containing compound includes formamide, N-methyl formamide, N,N-dimethyl formamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl pyrrolidone, 1,3-dimethyl imidazolidinone or ε-caprolactam, preferably formamide, N-methyl formamide, N,N-dimethyl formamide, 2-pyrrolidone or N-methyl-2-pyrrolidone, further preferably formamide, N-methyl formamide or N,N-dimethyl formamide. The nitrogen-containing compound can improve the compatibility of the ink and ensure the smoothness of printing.

[0044] In the present application, 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, chlorovinyl resin, chlorovinyl-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 application, the surfactant includes one or more of acetylenic diol, organosilicon and fluorine-containing surfactant, preferably acetylenic diol or organosilicon, further preferably acetylenic diol;

[0046] In the present application, the acetylenic diol 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, further preferably Surfynol 104, Surfynol 104E or Surfynol 104H.

[0047] In the present application, 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, further preferably BYK-306 or BYK-307;

[0048] The fluorine-containing surfactant is preferably BYK-340;

[0049] 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, 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, more preferably PROXEL CRL.

[0050] In the present application, the water includes deionized water or water after ultraviolet irradiation or sterilization, preferably deionized water.

[0051] The present application also provides a preparation method of the aqueous nano-pigment ink for inkjet printing, including the following steps:

[0052] Step 1): mixing water, synergist, water-soluble organic solvent, surfactant and bactericide, and then sequentially adding aqueous resin and pigment color paste and stirring to obtain crude ink;

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

[0054] In the present application, in step 1), the mixing is carried out under stirring, the stirring time is 5-20 min, preferably 10-15 min, further preferably 12 min;

[0055] The stirring is respectively carried out when the water-based resin and the pigment color paste are added, and the stirring time is independently 20-80 min, preferably 30-50 min, further preferably 40 min.

[0056] In the present application, in step 2), the aging temperature is 16-35℃, preferably 20-30℃, further preferably 25℃; the aging time is 15-36 h, preferably 20-30℃, further preferably 25℃.

[0057] The technical solutions provided by the present application are described in detail below in combination with examples, but they cannot be understood as limitations to the protection scope of the present application.

[0058] The present application provides a synergist, and 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 alkoxy;

[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 cation, equivalent of polyvalent cation, NH4 + , secondary ammonium ion, tertiary ammonium ion, quaternary ammonium ion, primary amine, secondary amine, tertiary amine or alcohol amine.

[0063] In the present application, the formula of the ink is preferably composed of the following components:

[0064] Pigment color paste: self-dispersed carbon black paste, 15wt%, self-made;

[0065] ZXJ: synergist, self-made;

[0066] BYK-190: dispersant;

[0067] GLY: glycerol;

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

[0069] TEGmBE: triethylene glycol monobutyl ether;

[0070] NMP: N-methyl pyrrolidone;

[0071] 101: aqueous resin, self-made;

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

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

[0074] Example 1

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

[0076] The structural formula of ethylenediaminetetramethylene phosphonic acid is:

[0077] Example 2

[0078] Different from Example 1, in this embodiment, a 30% potassium hydroxide aqueous solution was used to adjust the pH of the ethylenediaminetetramethylene phosphonic acid aqueous solution, and finally an EDTMPP solution was obtained, which was recorded as synergist B.

[0079] Example 3

[0080] Different from Example 1, in this embodiment, a 25% ammonia aqueous solution was used to adjust the pH of the ethylenediaminetetramethylene phosphonic acid aqueous solution, and finally an EDTMPA solution was obtained, which was recorded as synergist C.

[0081] Example 4

[0082] Different from Example 1, in this embodiment, a 50% triethanolamine aqueous solution was used to adjust the pH of the ethylenediaminetetramethylene phosphonic acid aqueous solution, and finally an EDTMPTIP solution was obtained, which was recorded as synergist D.

[0083] Example 5

[0084] Different from Example 1, in this embodiment, a 50% triisopropanolamine aqueous solution was used to adjust the pH of the ethylenediaminetetramethylene phosphonic acid aqueous solution, and finally an EDTMPTIP solution was obtained, which was recorded as synergist E.

[0085] Example 6

[0086] Different from example 1, in this example, the amine aqueous solution is composed of 50 mL water and 10.4 g diethylene triamine, the amount of phosphorous acid added is 41.7 g, and an aqueous solution of diethylene triamine penta(methylene phosphonic acid) (DTPMP) is obtained. The pH of the aqueous solution of diethylene triamine penta(methylene phosphonic acid) is adjusted to 9 using an aqueous solution of sodium hydroxide with a mass concentration of 30%, and water is added for adjustment, and finally a DTPMPS solution is obtained, which is recorded as synergist F.

[0087] The structural formula of diethylene triamine penta(methylene phosphonic acid) is as follows:

[0088] Example 7

[0089] Different from example 6, in this example, an aqueous solution of potassium hydroxide with a mass concentration of 30% is used to adjust the pH of the aqueous solution of diethylene triamine penta(methylene phosphonic acid), 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 solution of ammonia with a mass concentration of 25% is used to adjust the pH of the aqueous solution of diethylene triamine penta(methylene phosphonic acid), and finally a DTPMPA solution is obtained, which is recorded as synergist H.

[0092] Example 9

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

[0094] Example 10

[0095] Different from example 6, in this example, an aqueous solution of triisopropanolamine with a mass concentration of 50% is used to adjust the pH of the aqueous solution of diethylene triamine penta(methylene phosphonic acid), and finally a DTPMPTIP solution is obtained, which is recorded as synergist J.

[0096] Example 11

[0097] Into a reaction bottle, 28.37 g of monochloroacetic acid was added and dissolved in 22 mL of distilled water. 30 g of 40 wt% NaOH solution was added dropwise at 15 °C for 1.5 h. Then 5.16 g of diethylenetriamine was added dropwise under stirring, and the temperature was controlled at 20 °C during the dropwise addition. Subsequently, 12 g of 40% NaOH aqueous solution was added dropwise, and the reaction was continued at 40 °C for 11 h. The reaction solution was cooled to 8 °C. 26 mL of concentrated hydrochloric acid was added dropwise under stirring to adjust the pH value to 1.6, and the solution was left overnight. The crystals were filtered, washed with 40 mL of ice water, and dried under vacuum to obtain about 13 g of a crude product. The crude product was filtered after decolorization with distilled water to obtain a colorless transparent liquid, i.e., a diethylenetriamine pentaacetic acid (DTPA) solution. The pH value of the DTPA aqueous solution was adjusted to 9 using a 30% sodium hydroxide aqueous solution, and the final DTPA solution was obtained by adjusting the mass concentration to 30%. The final DTPA solution was recorded as synergist K.

[0098] The structural formula of diethylenetriamine pentaacetic acid is as follows:

[0099] Example 12

[0100] In this example, the pH value of the DTPA aqueous solution was adjusted using a 30% potassium hydroxide aqueous solution, and the final DTPA solution was obtained by adjusting the mass concentration to 30%. The final DTPA solution was recorded as synergist L.

[0101] Example 13

[0102] In this example, the pH value of the DTPA aqueous solution was adjusted using a 25% ammonia aqueous solution, and the final DTPA solution was obtained by adjusting the mass concentration to 30%. The final DTPA solution was recorded as synergist M.

[0103] Example 14

[0104] In this example, the pH value of the DTPA aqueous solution was adjusted using a 50% triethanolamine aqueous solution, and the final DTPA solution was obtained by adjusting the mass concentration to 30%. The final DTPA solution was recorded as synergist N.

[0105] Example 15

[0106] In this example, the pH value of the DTPA aqueous solution was adjusted using a 50% triisopropanolamine aqueous solution, and the final DTPA solution was obtained by adjusting the mass concentration to 30%. The final DTPA solution was recorded as synergist O.

[0107] Example 16

[0108] β-hydroxyethyl ethylenediamine 105 g was added into a three-necked flask equipped with a stirrer, thermometer, dropping funnel and ice-salt bath, and 100 g of concentrated sulfuric acid was added dropwise under stirring, the temperature was controlled at 10°C by ice-salt bath during the dropping process. After the dropping was completed, the ice-salt bath was removed, and toluene was added. Water in the reaction flask was removed by distillation under reduced pressure to obtain the intermediate ethylenediamine ethanol sulfate. After cooling to room temperature, sodium carbonate solution was added until no gas was released. Then, saturated sodium sulfite solution (151 g) was added for sulfonation. The reaction was refluxed at 110°C for 30 hours, and then part of the water was removed by distillation under reduced pressure. After cooling to 92°C, the mixture was filtered while hot. After the sodium sulfate and sodium sulfite crystals were removed, the crude ethylenediamine ethyl sulfonate sodium salt was obtained. After further cooling and crystallization, acidification and recrystallization, the fine ethylenediamine ethyl sulfonate was obtained. The pH of the ethylenediamine ethyl sulfonate was adjusted to 9 using 30% sodium hydroxide aqueous solution, and water was added to obtain a 30% ethylenediamine ethyl sulfonate sodium salt solution, which was recorded as synergist P.

[0109] The structural formula of ethylenediamine ethyl sulfonate is as follows:

[0110] Example 17

[0111] In this example, the pH of the ethylenediamine ethyl sulfonate was adjusted to 9 using 30% potassium hydroxide aqueous solution, and water was added to obtain a potassium ethylenediamine ethyl sulfonate solution, which was recorded as synergist Q.

[0112] Example 18

[0113] In this example, the pH of the ethylenediamine ethyl sulfonate was adjusted to 9 using 25% ammonia aqueous solution, and water was added to obtain an ammonium ethylenediamine ethyl sulfonate solution, which was recorded as synergist R.

[0114] Example 19

[0115] In this example, the pH of the diethylenetriamine pentamethylene phosphonic acid aqueous solution was adjusted to 9 using 50% triethanolamine aqueous solution, and water was added to obtain a triethanolamine ethylenediamine ethyl sulfonate solution, which was recorded as synergist S.

[0116] Example 20

[0117] In this example, the pH of the ethylenediamine ethyl sulfonate was adjusted to 9 using 50% triisopropanolamine aqueous solution, and water was added to obtain a triisopropanolamine ethylenediamine ethyl sulfonate solution, which was recorded as synergist T.

[0118] Example 21

[0119] Take 3 parts of synergist A, 10 parts of glycerol, 2 parts of 1,2-hexanediol, 3 parts of triethylene glycol monobutyl ether, 5 parts of N-methyl pyrrolidone, 1 part of Surfynol 104E, 0.2 parts of Proxel XL-2 and 40.8 parts of water, then add 15 parts of 101 resin and stir for 30 min, then add 20 parts of self-dispersed carbon black paste and continue to stir for 60 min to obtain a crude ink; the obtained crude ink is aged at 25℃ for 24h, then sequentially filtered and defoamed to obtain a water-based nano pigment ink for inkjet printing.

[0120] Examples 22-40

[0121] Different from Example 21, Examples 22-40 replace synergist A with synergists B-T, respectively.

[0122] Comparative Example 1

[0123] Different from Example 21, the synergist A is replaced with dispersant BYK-190.

[0124] Example 41

[0125] Take 5 parts of synergist A, 10 parts of glycerol, 2 parts of 1,2-hexanediol, 3 parts of triethylene glycol monobutyl ether, 5 parts of N-methyl pyrrolidone, 1 part of Surfynol 104E, 0.2 parts of Proxel XL-2 and 20.8 parts of water, then add 20 parts of 101 resin and stir for 30 min, then add 33 parts of self-dispersed carbon black paste and continue to stir for 60 min to obtain a crude ink; the obtained crude ink is aged at 25℃ for 24h, then sequentially filtered and defoamed to obtain a water-based nano pigment ink for inkjet printing.

[0126] Examples 42-60

[0127] Different from Example 41, Examples 42-60 replace synergist A with synergists B-T, respectively.

[0128] Comparative Example 2

[0129] Different from Example 41, the synergist A is replaced with dispersant BYK-190.

[0130] The inks obtained in Examples 21-60 and Comparative Examples 1-2 are tested, and the testing method is as follows:

[0131] 1) Evaluation of color development

[0132] The inks obtained in Examples 21-60 and Comparative Examples 1-2 are printed on ordinary printing paper to form 180mm*270mm solid color blocks, respectively, and the color density OD of the color blocks is measured by a spectrophotometer (purchased from Aicello (Shanghai) Color Technology Co., Ltd.).

[0133] Evaluation criteria are as follows:

[0134] A: OD value is 1.40 or more;

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

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

[0137] 2) Print fluidity

[0138] The inks obtained in Examples 21 to 60 and Comparative Examples 1 and 2 were printed on ordinary printing paper to form 180 mm * 270 mm solid color patches, 15 pieces were continuously printed, and then test strips were printed, and the test was observed.

[0139] Evaluation criteria are as follows:

[0140] A: Ink breakage is less than 3;

[0141] B: Ink breakage is more than 3 and less than 10;

[0142] C: Ink breakage is more than 10, 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 and 2 were printed on cotton cloth, high-temperature baked at 170°C for 60s, and then cooled to room temperature, and tested according to the method of GB / T 3920-2008 Textiles - Color fastness test - Rubbing fastness.

[0145] Evaluation criteria are as follows:

[0146] A: Rubbing fastness is 3 or more;

[0147] B: Rubbing fastness is 2 or more;

[0148] C: Rubbing fastness is less than 2.

[0149] 4) Ink storage stability

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

[0151] Evaluation criteria are as follows:

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

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

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

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

[0156] The test results of the properties of the inks obtained in Examples 21-40 and Comparative Example 1 are shown in Table 1.

[0157]

[0158]

[0159] The test results of the properties of the inks obtained in Examples 41-60 and Comparative Example 2 are shown in Table 2.

[0160]

[0161]

[0162] As can be seen from Tables 1 and 2, the water-based pigment ink provided by the present application has excellent performance in color strength, printing fluency, rubbing fastness and storage stability. In Comparative Examples 1 and 2, the dispersant BYK-190 is used instead of the synergist, which has a gap in color development, printing fluency and wet rubbing fastness compared with the examples of the present application. Especially, after increasing the ratio of pigment paste in the ink, the ink in Comparative Example 2 has improved color development, but the printing fluency, rubbing fastness and storage stability are all reduced.

[0163] As can be seen from the above examples, the present application provides a water-based nano pigment ink for inkjet printing and a preparation method thereof. The synergist of the present application can be dissociated into multiple pairs of cations and anions in water, and can form a complex with the pigment through hydrogen bonds, which has a dispersing and stabilizing effect on the pigment. It can inhibit the diffusion of the ink into 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, which can improve the rubbing resistance of the recording material. The synergist has good compatibility with other components in the ink, which can inhibit the growth of microorganisms in the ink, and is conducive to long-term stable storage of the ink. In addition, the synergist has excellent chemical stability and thermal stability, and is not easy to decompose in strong acid and strong base media. It has very low toxicity, no carcinogenic and teratogenic effect, low dose use is harmless to humans, animals and aquatic animals, and has no pollution to the ecological environment. The water-based pigment ink of the present application has excellent performance in color 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 inkjet head in the prior art.

[0164] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

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 mass: 10-40 parts of pigment paste, 0.5-20 parts of synergist, 5-35 parts of water-soluble organic solvent, 1-30 parts of water-based resin, 0.1-10 parts of surfactant, 0.05-1 parts of fungicide, and 10-80 parts of water; The structure of the synergist is as follows: ； Wherein, n=0-10, n is an integer, R1-R7 are independently one of H, C1-C18 alkyl and C1-C18 alkoxy; Q1 to Q5 independently include one of H, -OM, -SM, -COOM, -PO3M2 and -SO3M, wherein at least one of Q1 to Q5 is -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 water-based 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. The aqueous 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 water-based 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 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 diols, organic silicons and fluorine-containing surfactants.

6. The water-based nano-pigment ink for inkjet printing according to claim 5, characterized in that: 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.

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): Mix water, synergist, water-soluble organic solvent, surfactant and fungicide, then add water-based resin and pigment paste in sequence and stir to obtain rough ink; Step 2) aging, filtering, and defoaming the crude ink to obtain a 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 for 5 to 20 minutes; When adding water-based resin and pigment paste, they need to be stirred separately, and the stirring time is 20~80 minutes.

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

Images