Ink-jet printing water-based ink, preparation method thereof and composite film flexible package

Abstract

The invention belongs to the technical field of ink, and discloses ink-jet printing water-based ink, a preparation method thereof and a composite film flexible package, the ink-jet printing water-based ink comprises the following raw material components: color paste, a water-soluble organic solvent, water-based solid acrylic resin and deionized water; the color paste contains toner and a dispersing agent, and the dispersing agent is a naphthalene ethylene modified acrylic acid dispersing agent. A naphthalene ring structure is used as a core skeleton of the dispersant, so that the desorption phenomenon of the dispersant is effectively inhibited; meanwhile, a molecular design strategy of an acrylic functional group is introduced, so that the acrylic functional group and acrylic resin with excellent chain segment flexibility and chemical stability generate a synergistic effect, and effective coating and directional arrangement of pigment particles in a resin matrix are realized through an intermolecular interaction force. The prepared water-based ink not only has good ink-jet printing performance and long service life, but also has the excellent characteristics of quick drying, friction resistance, good weather resistance and the like, and is suitable for composite film flexible packaging.

Description

Technical Field

[0001] The invention belongs to the technical field of inks, and in particular relates to an inkjet printing water-based ink and a preparation method thereof, and a composite film flexible package. Background Art

[0002] With the continuous development of the market economy, the demand for packaging in all walks of life is also increasing year by year, and more and more attention is paid to the grade and quality of packaging. As a common packaging form, composite film flexible packaging is not only colorful and novel in pattern, which is conducive to becoming an important medium for downstream customers to promote products and establish brands, but also has many characteristics such as good flexibility, high transparency, good air and moisture barrier, low cost, and easy use. This makes composite film flexible packaging not only suitable for consumer and institutional products, but also for industrial use, making it a very practical packaging form. However, the existing inks used for composite film flexible packaging are mostly solvent-based inks. When this type of ink is colored, it is often accompanied by a large amount of solvent volatilization, resulting in poor air quality at the work site and failing to meet environmental protection requirements.

[0003] At the same time, the existing inks for composite film flexible packaging are usually gravure inks. This type of ink mainly mixes pigments, resins, solvents and additives in a certain proportion, and uses a grinder to refine the pigment particles to improve the stability of the ink and printing quality. The gravure ink is then made through stirring, filtering and performance adjustment. The gravure ink has a long history of development and mature technology, rich colors, fast drying speed, and can be suitable for high-speed printing. However, the large-scale use of organic solvents makes it less environmentally friendly, and it is flammable and explosive, posing a safety hazard. In addition, UV ink is also widely used in composite film soft packaging. This type of ink mainly premixes pigments, prepolymers, monomers, photoinitiators and additives in a certain proportion, and refines the pigment particles through a grinder to improve the stability of the ink and the printing quality. After stirring, filtering and performance adjustment, it can be made into UV ink. UV ink has the advantages of fast curing speed, good water resistance, friction resistance and chemical resistance, bright colors, high saturation, etc. It can provide high-quality printing effects in soft packaging printing, but the ink system is a weak solvent system, which has certain environmental pollution, and the energy consumption of ultraviolet lamps is large, and the equipment maintenance cost is also high. Therefore, it is necessary to develop water-based soft packaging ink.

[0004] Since water-based ink uses water as a solvent component, it is difficult to wet and spread on substrates such as plastic films with low surface tension, and it also faces problems such as difficulty in volatilization and drying. At the same time, due to its high flexibility and wide application scenarios, composite film flexible packaging also requires the ink to have certain scratch resistance and other capabilities, which inevitably requires the introduction of high adhesion agents into water-based inks, which in turn causes the ink to be unable to meet the requirements of inkjet printing. In addition, in order to ensure the inkjet printing performance of water-based inks, it is generally required that the viscosity of water-based pigment inks is low and the toner particles in the ink have good dispersibility, thereby improving the optical properties and weather stability of the ink system. Summary of the invention

[0005] The present invention aims at the technical problems such as low cost-effectiveness and insufficient environmental friendliness of existing gravure inks and UV inks, as well as technical defects in drying efficiency, wetting performance, substrate adhesion and the lack of inkjet adaptability of traditional water-based inks. Through molecular structure design and formulation system optimization, the present invention proposes an inkjet printing water-based ink and a preparation method thereof, and a composite film flexible packaging. The inkjet printing water-based ink has the advantages of fast drying speed, strong wettability and high adhesion strength, and the toner particles can be evenly dispersed in the water-based system, so that the ink system exhibits excellent optical properties and weather resistance stability.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides an inkjet printing water-based ink, wherein the raw material components of the inkjet printing water-based ink include color paste, water-soluble organic solvent, water-based solid acrylic resin and deionized water; the color paste contains toner and dispersant, and the dispersant is a naphthalene-ethylene modified acrylic dispersant; The preparation process of the naphthalene ethylene modified acrylic acid dispersant is as follows: 2-vinyl naphthalene, acrylic acid, maleic anhydride and benzoyl peroxide are added into an organic solvent, and reacted under a nitrogen atmosphere; the solid reaction product is washed with toluene, and then added into toluene and stirred; polyethylene glycol and p-toluenesulfonic acid are then added and the reaction is continued; and the naphthalene ethylene modified acrylic acid dispersant is obtained through evaporation and purification.

[0007] Specifically, the inkjet printing water-based ink of the present invention uses water-based solid acrylic resin and color paste as main raw materials, and the color paste adopts naphthalene ethylene modified acrylic dispersant, and constructs a dispersion system by using a naphthalene ring structure as the core skeleton of the dispersant. The electron cloud density characteristics of the naphthalene ring structure can significantly enhance the chemical adsorption stability of the dispersant on the surface of the toner (including inorganic pigments and organic pigments), thereby effectively inhibiting the desorption phenomenon of the dispersant. At the same time, the molecular design strategy of introducing acrylic functional groups in the dispersant is used to make it synergistic with the water-based acrylic solid resin with excellent segment flexibility and chemical stability, and realize the effective coating and directional arrangement of the toner particles in the resin matrix through intermolecular interaction forces. Therefore, the inkjet printing water-based ink of the present invention can not only ensure the uniformity of the dispersion of the toner during the film forming process, eliminate the accumulation phenomenon, but also make the ink system show excellent optical properties and weathering stability. At the same time, the present invention adopts a water-based solid acrylic resin, and utilizes the molecular design of high-density polar functional groups in the resin molecule to significantly improve the surface bonding strength of the ink on a variety of polymer substrates (including but not limited to BOPP, PET, PE) through interfacial chemistry, thereby improving the adhesion between the ink and the substrate.

[0008] In some embodiments of the present invention, the water-soluble organic solvent is selected from at least one of ethylene glycol, diethylene glycol, propylene glycol, glycerol, isopropanol, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and dipropylene glycol monobutyl ether.

[0009] In some embodiments of the present invention, the water-based solid acrylic resin is selected from at least one of Mitsubishi BR116, Hanwha Soluryl-820, BASF Joncryl 678, BASF Joncryl 67, and Hanwha Soluryl-160.

[0010] In some embodiments of the present invention, the organic solvent comprises dipropylene glycol dimethyl ether.

[0011] In some embodiments of the present invention, the raw materials for preparing the naphthalene vinyl modified acrylic dispersant include, by weight: 60-70 parts of 2-vinylnaphthalene, 10-20 parts of acrylic acid, 15-25 parts of maleic anhydride, 2-5 parts of benzoyl peroxide, 35-45 parts of polyethylene glycol, and 2-5 parts of p-toluenesulfonic acid.

[0012] In some embodiments of the present invention, the reaction is carried out at a temperature of 80-90° C. for 4-6 hours.

[0013] In some embodiments of the present invention, the continued reaction is carried out at a temperature of 60-70° C. for 8-12 hours.

[0014] In some embodiments of the present invention, the color paste further contains deionized water. The raw material components of the color paste include, by weight: 28-35 parts of color powder, 8-12 parts of dispersant, and 55-62 parts of deionized water.

[0015] In some embodiments of the present invention, the particle size range of the color paste is D 97 Between 0.2-0.6μm.

[0016] In some embodiments of the present invention, the preparation process of the color paste is: mixing color powder, deionized water and a dispersant, grinding and filtering to obtain the color paste.

[0017] In some embodiments of the present invention, the toner is BASF Heliogen Blue K 7090, and its grinding particle size is required to be D 97 Between 0.22-0.23 μm, a cyan color paste is obtained.

[0018] In some embodiments of the present invention, the toner is BASF Paliogen Red K 3580, and its grinding particle size is required to be D 97 Between 0.26-0.27 μm, a magenta color paste was obtained.

[0019] In some embodiments of the present invention, the toner is BASF Paliotol Yellow K 2142, and its grinding particle size is required to be D 97 Between 0.23-0.24 μm, a yellow color paste is obtained.

[0020] In some embodiments of the present invention, the toner is BASF Microlith Black 0066A, and its grinding particle size is required to be D 97 Between 0.20-0.21 μm, a black color paste is obtained.

[0021] In some embodiments of the present invention, the toner is titanium dioxide (DuPont Ti-Pure R760), and the grinding particle size is required to be D 97 Between 0.50-0.60 μm, a white color paste is obtained.

[0022] In some embodiments of the present invention, the raw material components of the inkjet printing water-based ink further include an auxiliary agent, and the auxiliary agent includes at least one of a wetting agent, a defoaming agent, and a surfactant.

[0023] In some embodiments of the present invention, the raw material components of the inkjet printing water-based ink include, by weight: 15-30 parts of color paste, 15-25 parts of water-soluble organic solvent, 2-3 parts of water-based solid acrylic resin, 40-60 parts of deionized water, and 2-5 parts of additives.

[0024] In some embodiments of the present invention, the wetting agent is selected from SURFYNOL 465, and the amount used is 2-3 parts by weight.

[0025] In some embodiments of the present invention, the defoaming agent is selected from at least one of BYK-018, BYK-024 and BASF Foamaster MO 2111 AG, ​​and the amount used is 0.2-0.5 parts by weight.

[0026] In some embodiments of the present invention, the surfactant is selected from polyethylene glycol, and the degree of polymerization of the polyethylene glycol is 200, 400 or 600, namely PEG-200, PEG-400 or PEG-600; the amount of the surfactant is 0.5-0.8 parts by weight.

[0027] In some embodiments of the present invention, the mass ratio of the aqueous solid acrylic resin to the water-soluble organic solvent is 1:(5-10), preferably 1:(5.7-8.8).

[0028] In some embodiments of the present invention, the mass ratio of the water-soluble organic solvent to deionized water is 1:(2-4), preferably 1:(2.3-3.1).

[0029] Specifically, the present invention controls the mass ratio of aqueous solid acrylic resin and water-soluble organic solvent within a threshold value of 1:10, and the mass ratio of water-soluble organic solvent to deionized water below a critical value of 1:2, respectively; to achieve precise regulation of ink surface tension and viscosity, thereby ensuring the stability of ink droplet formation and non-drying nozzles during continuous inkjet printing, and achieving an optimal balance between substrate penetration rate and drying efficiency by regulating the solvent volatilization gradient, thereby shortening the drying time and improving the smoothness of inkjet printing.

[0030] A second aspect of the present invention provides a method for preparing the above-mentioned inkjet printing aqueous ink, comprising the following steps: Firstly, the aqueous solid acrylic resin is dissolved, and then the dissolved aqueous solid acrylic resin is mixed with other preparation raw materials except the color paste; then the color paste is added, the mixing is continued, and the aqueous ink for inkjet printing is obtained.

[0031] In some embodiments of the present invention, the mixing method is to stir at a speed of 800-1500 rpm for 1-2 hours, and after adding the color paste, continue to stir at a speed of 800-1500 rpm for 3-4 hours.

[0032] In some embodiments of the present invention, the dissolution process of the aqueous solid acrylic resin is: adding the aqueous solid acrylic resin to deionized water, heating and stirring; then adding ammonia water, ethanolamine and a defoaming agent, and keeping the temperature.

[0033] In some embodiments of the present invention, during the dissolution of the aqueous solid acrylic resin, the dosage of each raw material is as follows, by weight: 35-45 parts of aqueous solid acrylic resin, 45-55 parts of deionized water, 6-10 parts of ammonia water, 1-2 parts of ethanolamine, and 0.4-0.6 parts of defoaming agent.

[0034] In some embodiments of the present invention, the heating temperature is 70-90°C.

[0035] In some embodiments of the present invention, the insulation time is 4-6 hours.

[0036] The third aspect of the present invention provides the use of the above-mentioned aqueous ink for inkjet printing.

[0037] In some embodiments of the present invention, the inkjet printing aqueous ink is applied to a composite film flexible package, which includes a plastic film and a pattern layer attached to the surface of the plastic film, and the pattern layer is printed by the inkjet printing aqueous ink.

[0038] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages: The present invention proposes a water-based inkjet printing ink system with fast drying characteristics, excellent system stability and high printing suitability through molecular structure design and formula system optimization. Among them: in terms of dispersion system construction, by adopting a naphthalene ring structure as the core skeleton of the dispersant, its high electron cloud density characteristics significantly enhance the chemical adsorption stability of the dispersant on the surface of the toner, and effectively inhibit the desorption of the dispersant. At the same time, the molecular design strategy of introducing acrylic functional groups is used to produce a synergistic effect with acrylic resins with excellent chain segment flexibility and chemical stability, and the effective coating and directional arrangement of pigment particles in the resin matrix are achieved through intermolecular interaction forces.

[0039] The inkjet printing water-based ink of the present invention not only ensures the uniformity of toner dispersion during film formation and eliminates accumulation, but also enables the ink system to exhibit excellent optical properties and weathering stability. In terms of film formation and adhesion enhancement, the molecular design based on the high-density polar functional groups in the resin molecules significantly improves the surface bonding strength of the ink on various polymer substrates through interfacial chemistry. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with the examples, so that the technical personnel of the relevant technical field can understand the present invention. It is necessary to point out here that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The non-essential improvements and adjustments made to the present invention by the skilled person in the relevant field according to the above invention content should still belong to the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0041] Example 1 A cyan inkjet printing water-based ink, whose raw material components include, by weight: 23 parts of cyan color paste, 21.7 parts of water-soluble organic solvent (including ethylene glycol, propylene glycol and dipropylene glycol monobutyl ether in a mass ratio of 6:3:1), 2.5 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-018 defoaming agent, 0.5 parts of PEG-200 surfactant, and 50 parts of deionized water.

[0042] The method for preparing the cyan inkjet printing aqueous ink comprises the following steps: (1) Dissolution of water-based solid acrylic resin Weigh the raw materials according to the weight ratio, including 40 parts of Mitsubishi BR116 water-based solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (containing not less than 25wt% ammonia), 1.5 parts of ethanolamine, and 0.5 parts of BYK-018 defoamer; then put the water-based solid acrylic resin into deionized water, heat it to 80°C and stir it at a speed of 800-1500 rpm; then slowly add ammonia water, ethanolamine and defoamer in turn, keep warm for 5 hours, and obtain the dissolved water-based solid acrylic resin.

[0043] (2) Preparation of dispersant In a reaction container filled with sufficient amount of dipropylene glycol dimethyl ether, 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride and 3 parts of benzoyl peroxide are added in order by weight to form a reaction system; then the reaction system is placed in a nitrogen atmosphere, kept stirring, the temperature is controlled at 90°C, and the reaction is carried out for 5 hours; after the reaction, the obtained white powder solid is washed with toluene, and then added to sufficient amount of toluene, 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid are added while stirring, the temperature is controlled at 70°C, and the reaction is carried out for 10 hours; after the reaction, it is evaporated and purified to obtain a naphthalene vinyl modified acrylic dispersant.

[0044] (3) Preparation of cyan color paste: Weigh the raw materials according to the weight ratio, including 32 parts of BASF Heliogen Blue K 7090 cyan toner, 58 parts of deionized water, and 10 parts of the dispersant prepared in step (2); then mix the toner, deionized water and dispersant evenly to form a slurry; then grind the slurry and filter it to obtain a particle size D 97 Cyan color paste between 0.22-0.23μm.

[0045] (4) Preparation of ink: Weigh the raw materials according to the mass relationship of the above-mentioned cyan inkjet printing water-based ink, then add deionized water, a water-soluble organic solvent, a wetting agent, a defoaming agent and a surfactant to the dissolved aqueous solid acrylic acid solid resin prepared in step (1) in sequence, stir at a speed of 800-1500 rpm for 1 hour, and mix evenly; then add the cyan color paste prepared in step (3), continue to stir at a speed of 800-1500 rpm for 3 hours, and filter to obtain the cyan inkjet printing water-based ink of this embodiment.

[0046] Example 2 A magenta inkjet printing water-based ink, whose raw material components include, by weight: 24 parts of magenta color paste, 22 parts of water-soluble organic solvent (including diethylene glycol, isopropanol and triethylene glycol monobutyl ether in a mass ratio of 5:4:1), 2.5 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-024 defoaming agent, 0.5 parts of PEG-400 surfactant, and 49.7 parts of deionized water.

[0047] The method for preparing the above-mentioned magenta inkjet printing water-based ink comprises the following steps: (1) Dissolution of water-based solid acrylic resin Weigh the raw materials according to the weight ratio, including 40 parts of Mitsubishi BR116 water-based solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (ammonia content not less than 25wt%), 1.5 parts of ethanolamine, and 0.5 parts of BYK-024 defoamer; then put the water-based solid acrylic resin into deionized water, heat it to 80°C and stir it at a speed of 800-1500 rpm; then slowly add ammonia water, ethanolamine and defoamer in turn, keep warm for 5 hours, and obtain the dissolved water-based solid acrylic resin.

[0048] (2) Preparation of dispersant In a reaction container filled with sufficient amount of dipropylene glycol dimethyl ether, 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride and 3 parts of benzoyl peroxide are added in order by weight to form a reaction system; then the reaction system is placed in a nitrogen atmosphere, kept stirring, the temperature is controlled at 90°C, and the reaction is carried out for 5 hours; after the reaction, the obtained white powder solid is washed with toluene, and then added to sufficient amount of toluene, 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid are added while stirring, the temperature is controlled at 70°C, and the reaction is carried out for 10 hours; after the reaction, it is evaporated and purified to obtain a naphthalene vinyl modified acrylic dispersant.

[0049] (3) Preparation of magenta color paste: Weigh the raw materials according to the weight ratio, including 27 parts of BASF Paliogen Red K 3580 magenta color powder, 63 parts of deionized water, and 10 parts of the dispersant prepared in step (2); then mix the color powder, deionized water and dispersant evenly to form a slurry; then grind the slurry and filter it to obtain a particle size D 97 Magenta color paste between 0.26-0.27μm.

[0050] (4) Preparation of ink: Weigh the raw materials according to the mass relationship of the above-mentioned magenta inkjet printing water-based ink, then add deionized water, a water-soluble organic solvent, a wetting agent, a defoaming agent and a surfactant to the dissolved aqueous solid acrylic acid solid resin prepared in step (1) in sequence, stir at a speed of 800-1500 rpm for 1 hour, and mix them evenly; then add the magenta color paste prepared in step (3), continue to stir at a speed of 800-1500 rpm for 3 hours, and filter to obtain the magenta inkjet printing water-based ink of this embodiment.

[0051] Example 3 A yellow inkjet printing water-based ink, whose raw material components include, by weight: 20 parts of yellow color paste, 22 parts of water-soluble organic solvent (including ethylene glycol, glycerol and diethylene glycol monobutyl ether in a mass ratio of 7:2:1), 2.5 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-018 defoaming agent, 0.5 parts of PEG-200 surfactant, and 52.7 parts of deionized water.

[0052] The method for preparing the above-mentioned inkjet printing water-based ink comprises the following steps: (1) Dissolution of water-based solid acrylic resin Weigh the raw materials according to the weight ratio, including 40 parts of Mitsubishi BR116 water-based solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (ammonia content not less than 25wt%), 1.5 parts of ethanolamine, and 0.5 parts of BYK-024 defoamer; then put the water-based solid acrylic resin into deionized water, heat it to 80°C and stir it at a speed of 800-1500 rpm; then slowly add ammonia water, ethanolamine and defoamer in turn, keep warm for 5 hours, and obtain the dissolved water-based solid acrylic resin.

[0053] (2) Preparation of dispersant In a reaction container filled with sufficient amount of dipropylene glycol dimethyl ether, 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride and 3 parts of benzoyl peroxide are added in order by weight to form a reaction system; then the reaction system is placed in a nitrogen atmosphere, kept stirring, the temperature is controlled at 90°C, and the reaction is carried out for 5 hours; after the reaction, the obtained white powder solid is washed with toluene, and then added to sufficient amount of toluene, 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid are added while stirring, the temperature is controlled at 70°C, and the reaction is carried out for 10 hours; after the reaction, it is evaporated and purified to obtain a naphthalene vinyl modified acrylic dispersant.

[0054] (3) Preparation of yellow color paste: Weigh the raw materials according to the weight ratio, including 25 parts of Paliotol Yellow K 2142 yellow toner, 65 parts of deionized water, and 10 parts of the dispersant prepared in step (2); then mix the toner, deionized water and dispersant evenly to form a slurry; then grind the slurry and filter it to obtain a particle size D 97 Yellow color paste between 0.23-0.24μm.

[0055] (4) Preparation of ink: Weigh the raw materials according to the mass relationship of the yellow inkjet printing water-based ink, then add deionized water, a water-soluble organic solvent, a wetting agent, a defoaming agent and a surfactant to the dissolved water-based solid acrylic acid solid resin prepared in step (1) in sequence, stir at a speed of 800-1500 rpm for 1 hour, and mix evenly; then add the yellow color paste prepared in step (3), continue to stir at a speed of 800-1500 rpm for 3 hours, and filter to obtain the yellow inkjet printing water-based ink of this embodiment.

[0056] Example 4 A black water-based ink for inkjet printing, whose raw material components include, by weight: 25 parts of black color paste, 22 parts of water-soluble organic solvent (including ethylene glycol, glycerol and diethylene glycol monobutyl ether in a mass ratio of 7:2:1), 2.5 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-024 defoaming agent, 0.5 parts of PEG-400 surfactant, and 49.7 parts of deionized water.

[0057] The method for preparing the above-mentioned black inkjet printing aqueous ink comprises the following steps: (1) Dissolution of water-based solid acrylic resin Weigh the raw materials according to the weight ratio, including 40 parts of Mitsubishi BR116 water-based solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (ammonia content not less than 25wt%), 1.5 parts of ethanolamine, and 0.5 parts of BYK-024 defoamer; then put the water-based solid acrylic resin into deionized water, heat it to 80°C and stir it at a speed of 800-1500 rpm; then slowly add ammonia water, ethanolamine and defoamer in turn, keep warm for 5 hours, and obtain the dissolved water-based solid acrylic resin.

[0058] (2) Preparation of dispersant In a reaction container filled with sufficient amount of dipropylene glycol dimethyl ether, 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride and 3 parts of benzoyl peroxide are added in order by weight to form a reaction system; then the reaction system is placed in a nitrogen atmosphere, kept stirring, the temperature is controlled at 90°C, and the reaction is carried out for 5 hours; after the reaction, the obtained white powder solid is washed with toluene, and then added to sufficient amount of toluene, 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid are added while stirring, the temperature is controlled at 70°C, and the reaction is carried out for 10 hours; after the reaction, it is evaporated and purified to obtain a naphthalene vinyl modified acrylic dispersant.

[0059] (3) Preparation of black color paste: Weigh the raw materials according to the weight ratio, including 30 parts of Microlith Black 0066A black color powder, 60 parts of deionized water, and 10 parts of the dispersant prepared in step (2); then mix the color powder, deionized water and dispersant evenly to make a slurry; then grind the slurry and filter it to obtain a particle size D 97 Black color paste between 0.20-0.21μm.

[0060] (4) Preparation of ink: Weigh the raw materials according to the mass relationship of the above-mentioned black inkjet printing water-based ink, then add deionized water, a water-soluble organic solvent, a wetting agent, a defoaming agent and a surfactant to the dissolved water-based solid acrylic acid solid resin prepared in step (1) in sequence, stir at a speed of 800-1500 rpm for 1 hour, and mix them evenly; then add the black color paste prepared in step (3), continue to stir at a speed of 800-1500 rpm for 3 hours, and filter to obtain the black inkjet printing water-based ink of this embodiment.

[0061] Example 5 A white inkjet printing water-based ink, whose raw material components include, by weight: 25 parts of white color paste, 17 parts of water-soluble organic solvent (including ethylene glycol, glycerol and diethylene glycol monobutyl ether in a mass ratio of 7:2:1), 3 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-018 defoaming agent, 0.5 parts of PEG-400 surfactant, and 52.2 parts of deionized water.

[0062] The method for preparing the above-mentioned white inkjet printing aqueous ink comprises the following steps: (1) Dissolution of water-based solid acrylic resin Weigh the raw materials according to the weight ratio, including 40 parts of Mitsubishi BR116 water-based solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (containing not less than 25wt% ammonia), 1.5 parts of ethanolamine, and 0.5 parts of BYK-018 defoamer; then put the water-based solid acrylic resin into deionized water, heat it to 80°C and stir it at a speed of 800-1500 rpm; then slowly add ammonia water, ethanolamine and defoamer in turn, keep warm for 5 hours, and obtain the dissolved water-based solid acrylic resin.

[0063] (2) Preparation of dispersant In a reaction container filled with sufficient amount of dipropylene glycol dimethyl ether, 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride and 3 parts of benzoyl peroxide are added in order by weight to form a reaction system; then the reaction system is placed in a nitrogen atmosphere, kept stirring, the temperature is controlled at 90°C, and the reaction is carried out for 5 hours; after the reaction, the obtained white powder solid is washed with toluene, and then added to sufficient amount of toluene, 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid are added while stirring, the temperature is controlled at 70°C, and the reaction is carried out for 10 hours; after the reaction, it is evaporated and purified to obtain a naphthalene vinyl modified acrylic dispersant.

[0064] (3) Preparation of white color paste: Weigh the raw materials according to the weight ratio, including 45 parts of DuPont Ti-Pure R760 titanium dioxide, 45 parts of deionized water, and 10 parts of the dispersant prepared in step (2); then mix the color powder, deionized water and dispersant evenly to form a slurry; then grind the slurry and filter it to obtain a particle size D 97 White color paste between 0.50-0.60μm.

[0065] (4) Preparation of ink: Weigh the raw materials according to the mass relationship of the above-mentioned white inkjet printing water-based ink, then add deionized water, a water-soluble organic solvent, a wetting agent, a defoaming agent and a surfactant to the dissolved water-based solid acrylic solid resin prepared in step (1) in sequence, stir at a speed of 800-1500 rpm for 1 hour, and mix evenly; then add the white color paste prepared in step (3), continue to stir at a speed of 800-1500 rpm for 3 hours, and filter to obtain the white inkjet printing water-based ink of this embodiment.

[0066] Comparative Example 1 The difference between Comparative Example 1 and Example 5 is that the raw material components of the white inkjet printing aqueous ink are different. Comparative Example 1 uses an equal amount of styrene-acrylic copolymer resin emulsion (Wanhua Chemical Archsol 8016) to replace the Mitsubishi BR116 aqueous solid acrylic resin in Example 5.

[0067] Comparative Example 2 The difference between Comparative Example 2 and Example 5 is only that the raw material components of the white inkjet printing water-based ink are different. The raw material components of the white inkjet printing water-based ink of Comparative Example 2 include, by weight: 25 parts of white color paste, 17 parts of a water-soluble organic solvent (including ethylene glycol, glycerol and diethylene glycol monobutyl ether in a mass ratio of 7:2:1), 5 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-018 defoaming agent, 0.5 parts of PEG-400 surfactant, and 50.2 parts of deionized water.

[0068] Comparative Example 3 The difference between Comparative Example 3 and Example 5 is only that the raw material components of the white inkjet printing water-based ink are different. The raw material components of the white inkjet printing water-based ink of Comparative Example 3 include, by weight: 25 parts of white color paste, 25 parts of a water-soluble organic solvent (including ethylene glycol, glycerol and diethylene glycol monobutyl ether in a mass ratio of 7:2:1), 3 parts of Mitsubishi BR116 water-based solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK Chemical BYK-018 defoaming agent, 0.5 parts of PEG-400 surfactant, and 44.2 parts of deionized water.

[0069] Comparative Example 4 The difference between Comparative Example 4 and Example 5 is that the raw materials for preparing the white color paste are different. Comparative Example 4 uses an equal amount of German BASF's water-based styrene-acrylic acid copolymer emulsion dispersant Acronal Proof 1108 AP to replace the naphthalene ethylene modified acrylic acid dispersant prepared in step (2) of Example 5.

[0070] Performance Testing The performance of the inkjet printing water-based ink samples prepared in the above Examples 1-5 and Comparative Examples 1-4 was tested. Specifically, the viscosity of the ink was measured using a viscometer, the surface tension of the ink was measured using a surface tension meter, and the particle size D of the ink was measured using an OMEC laser particle size analyzer. 50 and D 97 , Mettler FE38 was used to measure the conductivity of ink.

[0071] Drying time: Use a 10 μm film applicator to scrape the ink flat on the PET substrate, and then use a stopwatch to record the time required for drying.

[0072] The adhesion fastness is measured according to the national standard GB / T 13217.7-2009 “Test method for adhesion fastness of liquid ink”.

[0073] The inkjet printing fluency test process is: use the inkjet printer to print the ink continuously for 100m, check the print head without cleaning, and observe the number of broken holes of the ink on the status bar.

[0074] The sedimentation test process is as follows: use a 10 mL test tube filled with inkjet printing water-based ink and let it stand for two months to observe whether there is stratification and sedimentation. Record the volume of the upper clear liquid after stratification. The sedimentation rate = upper clear liquid volume / (10 mL).

[0075] The light fastness is measured with reference to the national standard GB1710-79 "Determination of light fastness of pigments", wherein: the light fastness level is divided into level 1 to level 8, and level 1 has the worst light fastness and level 8 has the best light fastness.

[0076] The test results are shown in Table 1.

[0077] Table 1:

[0078] It can be seen from the test results in Table 1 that in Examples 1-5, by adding a certain amount of aqueous solid acrylic resin and using a specific naphthalene vinyl modified acrylic dispersant to disperse the toner, and controlling the dosage relationship between the resin and the water-soluble organic solvent, and the water-soluble organic solvent and the deionized water, the prepared inkjet printing aqueous ink not only has excellent stability, fast drying speed and good adhesion when printed on the substrate, which can greatly improve the production efficiency and production quality of the composite film flexible packaging, but also the ink itself also shows good printing performance, has a relatively suitable viscosity and surface tension, has a good effect in the inkjet printing process, does not block the nozzle, and has very few or even no broken holes in the printed pattern; and has a good service life, with a low ink sedimentation rate in two months, and has good light resistance.

[0079] By comparing the performance of the inkjet printing water-based ink prepared in Comparative Examples 1-4 with that in Example 5, it can be seen that the selection of resin and dispersant, as well as the dosage relationship between the resin, water-soluble organic solvent and deionizer, have a great influence on the ink performance and printing quality.

[0080] Among them: In Comparative Example 1, due to the use of styrene-acrylic copolymer resin emulsion, the high molecular weight of solid acrylic resin cannot be obtained, resulting in the ink filler being unable to effectively adhere to the flexible packaging material, and the printed image is easy to fall off. At the same time, the light resistance and stability of the ink are also poor, and the resin emulsion is greatly affected by the emulsifier, which seriously affects the stability of the ink, causing the ink to be stratified or precipitated during long-term storage and use, thereby affecting the continuity of printing.

[0081] In Comparative Example 2, the content of aqueous solid acrylic resin is too high, which increases the viscosity of the ink, and further causes the fluidity of the ink in the nozzle to deteriorate or the formation of ink droplets, thereby causing nozzle blockage, which manifests as many broken holes in printing, affecting the production efficiency of flexible packaging. In addition, too much resin in the ink will slow down the drying speed, resulting in blurred images due to the ink not drying during high-speed printing in production.

[0082] The content of water-soluble organic solvent in Comparative Example 3 is too high, which, on the one hand, causes the viscosity of the ink to be too high, affecting the printing smoothness of the ink, and also slows down the drying speed of the ink, affecting the production of high-speed printing; on the other hand, it causes the life of the ink to be reduced. This is because too much organic solvent causes the resin components in the ink components to decompose or swell, etc., which damages its own performance, resulting in a decrease in the life of the ink.

[0083] Comparative Example 4 uses a dispersant imported from abroad, in which the main chain of the dispersant adopts a benzene ring structure. Compared with the naphthalene ring structure of the present invention, the basic performance of the prepared ink is equivalent, but there are problems of poor long-term stability and poor adhesion and light resistance. In summary, the present invention uses water-based solid acrylic resin and a specific naphthalene vinyl modified acrylic dispersant as main raw materials and controls the dosage relationship between the raw materials. The prepared inkjet printing water-based ink not only has good inkjet printing performance and long life, but also has excellent characteristics such as quick drying, good friction resistance and good weather resistance, which is of great progressive significance to the production of the flexible packaging industry.

[0084] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should belong to the protection scope of the present invention.

Claims

1. An inkjet printing water-based ink, characterized in that: The raw material components of the inkjet printing water-based ink include color paste, water-soluble organic solvent, water-based solid acrylic resin and deionized water; the color paste contains toner and dispersant, and the dispersant is a naphthalene-ethylene modified acrylic dispersant; The preparation process of the naphthalene ethylene modified acrylic acid dispersant is as follows: 2-vinyl naphthalene, acrylic acid, maleic anhydride and benzoyl peroxide are added into an organic solvent, and reacted under a nitrogen atmosphere; then the solid reaction product is washed with toluene, and then added into toluene and stirred; polyethylene glycol and p-toluenesulfonic acid are added, and the reaction is continued; and the naphthalene ethylene modified acrylic acid dispersant is obtained through evaporation and purification.

2. The inkjet printing aqueous ink according to claim 1, characterized in that: The raw materials for preparing the naphthalene-ethylene-modified acrylic acid dispersant include, by weight: 60-70 parts of 2-vinylnaphthalene, 10-20 parts of acrylic acid, 15-25 parts of maleic anhydride, 2-5 parts of benzoyl peroxide, 35-45 parts of polyethylene glycol, and 2-5 parts of p-toluenesulfonic acid.

3. The inkjet printing aqueous ink according to claim 1, characterized in that: The reaction is carried out at a temperature of 80-90° C. for 4-6 hours; and / or, the continued reaction is carried out at a temperature of 60-70° C. for 8-12 hours.

4. The inkjet printing water-based ink according to claim 1, characterized in that: The color paste also contains deionized water. The raw material components of the color paste include, by weight: 28-35 parts of color powder, 8-12 parts of dispersant, and 55-62 parts of deionized water; and / or the particle size range of the color paste is D 97 Between 0.2-0.6μm.

5. The inkjet printing aqueous ink according to claim 1, characterized in that: The raw material components of the inkjet printing water-based ink also include auxiliary agents, and the auxiliary agents include at least one of a wetting agent, a defoaming agent, and a surfactant.

6. The inkjet printing aqueous ink according to claim 5, characterized in that: The raw material components of the inkjet printing water-based ink include, by weight: 15-30 parts of color paste, 15-25 parts of water-soluble organic solvent, 2-3 parts of water-based solid acrylic resin, 40-60 parts of deionized water, and 2-5 parts of auxiliary agent.

7. The inkjet printing aqueous ink according to claim 6, characterized in that: The mass ratio of the aqueous solid acrylic resin to the water-soluble organic solvent is 1:(5-10); and / or the mass ratio of the water-soluble organic solvent to deionized water is 1:(2-4).

8. A method for preparing an aqueous ink for inkjet printing according to any one of claims 1 to 7, characterized in that: The following steps are involved: Firstly, the water-based solid acrylic resin is dissolved, and then the dissolved water-based solid acrylic resin is mixed with other preparation raw materials except the color paste; Then, color paste is added, mixing is continued, and filtering is performed to obtain the inkjet printing water-based ink.

9. The method for preparing an aqueous ink for inkjet printing according to claim 8, characterized in that: The dissolving process of the water-based solid acrylic resin is as follows: adding the water-based solid acrylic resin into deionized water, heating and stirring; then adding ammonia water, ethanolamine and a defoaming agent, and keeping the temperature.

10. A composite film flexible package, characterized in that: The composite film flexible package comprises a plastic film and a pattern layer attached to the surface of the plastic film, wherein the pattern layer is printed by the inkjet printing water-based ink according to any one of claims 1 to 7.

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