An inkjet printing aqueous ink, its preparation method, and composite film soft packaging

Abstract

The present invention belongs to the technical field of inks, and discloses an inkjet printing aqueous ink, a preparation method thereof, and a composite film soft packaging. The raw material components of the inkjet printing aqueous ink include color paste, water-soluble organic solvent, aqueous solid acrylic resin, and deionized water; and the color paste contains color powder and dispersant, and the dispersant is a naphthalene ethylene modified acrylic dispersant. By using the naphthalene ring structure as the core skeleton of the dispersant, the present invention effectively inhibits the desorption phenomenon of the dispersant; at the same time, the molecular design strategy of introducing acrylic functional groups is adopted to make it produce a synergistic effect with the acrylic resin having excellent chain segment flexibility and chemical stability, and the pigment particles are effectively coated and oriented in the resin matrix through intermolecular interaction forces. The prepared aqueous ink not only has good inkjet printing performance and high lifespan, but also has excellent characteristics such as quick drying, good friction resistance, and good weather resistance, and is suitable for composite film soft packaging.

Description

Technical Field

[0001] The present invention belongs to the technical field of inks, and particularly relates to an inkjet printing aqueous ink, a preparation method thereof, and a composite film flexible packaging. Background Art

[0002] With the continuous development of the market economy, the demand for packaging in all walks of life has been 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 not only has bright colors and novel patterns, which is conducive to becoming an important medium for the product promotion and brand establishment of downstream customers, but also has many characteristics such as good flexibility, high transparency, good gas and moisture barrier properties, low cost, and convenient use. This makes composite film flexible packaging applicable to both consumer and institutional products and industrial uses, becoming a very practical packaging form. However, most of the existing inks for composite film flexible packaging are solvent-based inks. When such inks are used for coloring, a large amount of solvent often volatilizes, resulting in poor air quality at the operation site and failing to meet the environmental protection requirements.

[0003] At the same time, the existing inks for composite film flexible packaging are usually gravure inks. Such inks are mainly prepared by mixing pigments, resins, solvents, and additives in a certain proportion, and then refining the pigment particles through a grinding machine to improve the stability and printing quality of the inks. After that, through operations such as stirring, filtering, and performance adjustment, the gravure inks can be made. Gravure inks have a long development history, mature processes, rich colors, and fast drying speeds, and are suitable for high-speed printing. However, the extensive use of organic solvents results in poor environmental protection, and they are flammable and explosive, posing safety hazards. In addition, UV inks are also widely used in composite film flexible packaging. Such inks are mainly prepared by premixing pigments, prepolymers, monomers, photoinitiators, and additives in a certain proportion, and then refining the pigment particles through a grinding machine to improve the stability and printing quality of the inks. Subsequently, through operations such as stirring, filtering, and performance adjustment, the UV inks can be made. UV inks have the advantages of fast curing speed, good water resistance, abrasion resistance, chemical resistance, bright colors, and high saturation, and can provide high-quality printing effects in flexible packaging printing. However, the ink system is a weak solvent system, causing certain environmental pollution, and the energy consumption of ultraviolet lamps is relatively large, and the equipment maintenance cost is also relatively high. Therefore, it is necessary to develop aqueous flexible packaging inks.

[0004] Since water-based inks use water as a solvent component, it is difficult for them to wet and spread on substrates such as plastic films with low surface tension. At the same time, they also face problems such as difficult volatilization and drying. At the same time, due to the high flexibility and wide range of applicable scenarios of composite film soft packaging, the ink is also required to have certain scratch resistance and other capabilities. Inevitably, high adhesives need to be introduced into the water-based ink, which in turn causes the ink to fail to meet the requirements of inkjet printing. In addition, 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 resistance stability of the ink system. Summary of the Invention

[0005] In view of the technical defects such as low cost-effectiveness and insufficient environmental friendliness of existing gravure inks and UV inks, as well as the technical problems existing in traditional water-based inks in terms of drying efficiency, wetting performance, substrate adhesion, etc., and the lack of inkjet adaptability, through molecular structure design and formulation system optimization, the present invention provides an inkjet printing water-based ink, its preparation method, and a composite film soft packaging. The inkjet printing water-based ink has a fast drying speed, strong wettability, high adhesion strength, and the toner particles can be uniformly dispersed in the water-based system, enabling the ink system to exhibit excellent optical properties and weather resistance stability.

[0006] To solve the above technical problems, in the first aspect of the present invention, an inkjet printing water-based ink is provided. 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 a dispersant, and the dispersant is a naphthylethylene-modified acrylic dispersant.

[0007] The preparation process of the naphthylethylene-modified acrylic dispersant is as follows: 2-vinylnaphthalene, acrylic acid, maleic anhydride, and benzoyl peroxide are added to an organic solvent, and the reaction is carried out under a nitrogen atmosphere; after washing the solid reaction product with toluene, it is added to toluene and stirred; then polyethylene glycol and p-toluenesulfonic acid are added, and the reaction is continued; after evaporation and purification, the naphthylethylene-modified acrylic dispersant is obtained.

[0008] Specifically, the inkjet printing aqueous ink of the present invention uses aqueous solid acrylic resin and color paste as the main raw materials, and the color paste uses naphthylethylene-modified acrylic dispersant. By using the naphthalene ring structure as the core skeleton of the dispersant to construct a dispersion system, the electron cloud density characteristics of the naphthalene ring structure can significantly enhance the chemical adsorption stability of the dispersant on the surface of 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 into the dispersant enables it to synergistically interact with the aqueous acrylic solid resin with excellent chain segment flexibility and chemical stability, and effectively coat and orient the arrangement of toner particles in the resin matrix through intermolecular interaction forces. Therefore, the inkjet printing aqueous ink of the present invention can not only ensure the dispersion uniformity of toner during the film-forming process and eliminate the accumulation phenomenon, but also make the ink system exhibit excellent optical properties and weather resistance stability. At the same time, the present invention uses aqueous solid acrylic resin, and through the molecular design of high-density polar functional groups in the resin molecules, the surface bonding strength of the ink on various polymer substrates (including but not limited to BOPP, PET, PE) is significantly improved through interfacial chemical action, thereby enhancing the adhesion between the ink and the substrate.

[0009] 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, isopropyl alcohol, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and dipropylene glycol monobutyl ether.

[0010] In some embodiments of the present invention, the aqueous 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.

[0011] In some embodiments of the present invention, the organic solvent includes dipropylene glycol dimethyl ether.

[0012] In some embodiments of the present invention, the raw materials for preparing the naphthylethylene-modified acrylic dispersant, by weight, include: 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.

[0013] In some embodiments of the present invention, the reaction is carried out at a temperature of 80-90 °C for 4-6 hours.

[0014] In some embodiments of the present invention, the continued reaction is carried out at a temperature of 60-70 °C for 8-12 hours.

[0015] 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.

[0016] In some embodiments of the present invention, the particle size range of the color paste is D 97 Between 0.2 and 0.6 μm.

[0017] In some embodiments of the present invention, the preparation process of the color paste is as follows: after mixing the color powder, deionized water and dispersant, grinding and filtering are carried out to obtain the color paste.

[0018] In some embodiments of the present invention, the color powder is BASF Heliogen Blue K 7090, and its required grinding particle size is D 97 Between 0.22 and 0.23 μm to obtain a cyan color paste.

[0019] In some embodiments of the present invention, the color powder is BASF Paliogen Red K 3580, and its required grinding particle size is D 97 Between 0.26 and 0.27 μm to obtain a magenta color paste.

[0020] In some embodiments of the present invention, the color powder is BASF Paliotol Yellow K 2142, and its required grinding particle size is D 97 Between 0.23 and 0.24 μm to obtain a yellow color paste.

[0021] In some embodiments of the present invention, the color powder is BASF Microlith Black 0066A, and its required grinding particle size is D 97 Between 0.20 and 0.21 μm to obtain a black color paste.

[0022] In some embodiments of the present invention, the color powder is titanium dioxide (DuPont Ti-Pure R760), and its required grinding particle size is D 97 Between 0.50 and 0.60 μm to obtain a white color paste.

[0023] In some embodiments of the present invention, the raw material components of the inkjet printing aqueous ink further include additives, and the additives include at least one of a wetting agent, an antifoaming agent, and a surfactant.

[0024] In some embodiments of the present invention, the raw material components of the inkjet printing aqueous ink include, by weight: 15-30 parts of color paste, 15-25 parts of water-soluble organic solvent, 2-3 parts of aqueous solid acrylic resin, 40-60 parts of deionized water, and 2-5 parts of additives.

[0025] In some embodiments of the present invention, the wetting agent is selected from SURFYNOL 465, and the dosage is 2-3 parts by weight.

[0026] In some embodiments of the present invention, the defoaming agent is selected from at least one of BYK-018, BYK-024 of BYK Chemie and Foamaster MO 2111 AG of BASF, and the dosage is 0.2-0.5 parts by weight.

[0027] In some embodiments of the present invention, the surfactant is selected from polyethylene glycol, and the degrees of polymerization of the polyethylene glycol are 200, 400 or 600 respectively, that is, PEG-200, PEG-400 or PEG-600; the dosage of the surfactant is 0.5-0.8 parts by weight.

[0028] 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).

[0029] 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).

[0030] Specifically, in the present invention, by controlling the aqueous solid acrylic resin and the water-soluble organic solvent within the threshold of 1:10 respectively, and the mass ratio of the water-soluble organic solvent to deionized water below the critical value of 1:2; precise regulation of the surface tension and viscosity of the ink is achieved, which not only ensures the stability of ink droplet formation and no nozzle drying during continuous inkjet printing, but also optimizes the balance between the substrate penetration rate and the drying efficiency by regulating the solvent evaporation gradient, thereby shortening the drying time and improving the smoothness of inkjet printing.

[0031] The second aspect of the present invention provides a method for preparing the above inkjet printing aqueous ink, comprising the following steps:

[0032] First, dissolve the aqueous solid acrylic resin, and then mix the dissolved aqueous solid acrylic resin with other preparation raw materials except the color paste; then add the color paste, continue to mix, and filter to obtain the inkjet printing aqueous ink.

[0033] In some embodiments of the present invention, the mixing method is stirring at a speed of 800-1500 revolutions per minute, stirring for 1-2 hours first, and then continuing to stir at a speed of 800-1500 revolutions per minute for 3-4 hours after adding the color paste.

[0034] In some embodiments of the present invention, the dissolution process of the aqueous solid acrylic resin is as follows: Add the aqueous solid acrylic resin to deionized water, heat and stir; then add ammonia water, ethanolamine and defoamer, and keep warm.

[0035] In some embodiments of the present invention, during the dissolution process of the aqueous solid acrylic resin, the dosage relationship of each raw material, by weight, is: 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 defoamer.

[0036] In some embodiments of the present invention, the heating temperature is 70-90 °C.

[0037] In some embodiments of the present invention, the heat preservation time is 4-6 hours.

[0038] The third aspect of the present invention provides the application of the above inkjet printing aqueous ink.

[0039] In some embodiments of the present invention, the inkjet printing aqueous ink is applied to a composite film soft 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 above inkjet printing aqueous ink.

[0040] The above technical solution of the present invention has at least the following technical effects or advantages compared with the prior art:

[0041] Through molecular structure design and formulation system optimization, the present invention proposes an aqueous inkjet printing ink system with fast drying characteristics, excellent system stability and high printing suitability. Among them: In terms of constructing the dispersion system, by using the naphthalene ring structure as the core skeleton of the dispersant, its high electron cloud density characteristic significantly enhances the chemical adsorption stability of the dispersant on the surface of the toner, effectively inhibiting the desorption phenomenon of the dispersant. At the same time, the molecular design strategy of introducing acrylic functional groups enables it to have a synergistic effect with the acrylic resin with excellent chain segment flexibility and chemical stability, and realizes the effective coating and orientation arrangement of pigment particles in the resin matrix through intermolecular interaction forces.

[0042] The inkjet printing aqueous ink of the present invention not only ensures the uniformity of toner dispersion during the film-forming process and eliminates the stacking phenomenon, but also makes the ink system exhibit excellent optical properties and weather resistance stability. In terms of film-forming and adhesion strengthening, based on the molecular design of high-density polar functional groups in the resin molecule, the surface bonding strength of the ink on various polymer substrates is significantly improved through interfacial chemical action. Detailed embodiments

[0043] The present invention will be specifically described below in conjunction with embodiments to facilitate the understanding of those skilled in the art. It is necessary to specifically point out here that the embodiments are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art, based on the above-mentioned inventive content, make non-essential improvements and adjustments to the present invention, which should still fall within the protection scope of the present invention. At the same time, for the raw materials not detailed below, they are all commercially available products; for the process steps or preparation methods not detailed, they are all process steps or preparation methods known to those skilled in the art.

[0044] Example 1

[0045] A cyan inkjet printing aqueous ink, the raw material components of which by weight include: 23 parts of cyan color paste, 21.7 parts of water-soluble organic solvent (including ethylene glycol, propylene glycol and dipropylene glycol monobutyl ether with a mass ratio of 6:3:1), 2.5 parts of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK-018 defoaming agent from BYK Chemie, 0.5 parts of PEG-200 surfactant, and 50 parts of deionized water.

[0046] The preparation method of the above-mentioned cyan inkjet printing aqueous ink includes the following steps:

[0047] (1) Dissolution of aqueous solid acrylic resin

[0048] Weigh each raw material according to the weight ratio, including 40 parts of Mitsubishi BR116 aqueous 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-018 defoaming agent from BYK Chemie; then put the aqueous solid acrylic resin into deionized water, heat to 80°C and stir at a speed of 800 - 1500 revolutions per minute; then slowly add ammonia water, ethanolamine and defoaming agent in sequence, and keep warm for 5 hours to obtain the dissolved aqueous solid acrylic resin.

[0049] (2) Preparation of dispersant

[0050] In a reaction vessel filled with sufficient dipropylene glycol dimethyl ether, add 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride, and 3 parts of benzoyl peroxide in sequence according to the weight ratio to form a reaction system; then place the reaction system in a nitrogen atmosphere, keep stirring, control the temperature at 90°C, and react for 5 hours; after the reaction, wash the obtained white powder solid with toluene, then add it to sufficient toluene, add 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid while stirring, control the temperature at 70°C, and react for 10 hours; after the reaction, carry out evaporation and purification to obtain a naphthylethylene-modified acrylic dispersant.

[0051] (3) Preparation of cyan color paste:

[0052] Weigh each raw material according to the weight ratio, including 32 parts of BASF Heliogen Blue K 7090 cyan color powder, 58 parts of deionized water, and 10 parts of the dispersant prepared in step (2); then mix the color powder, deionized water, and the dispersant evenly to form a slurry; then grind and filter the slurry to obtain a cyan color paste with a particle size D 97 between 0.22 - 0.23 μm.

[0053] (4) Preparation of ink:

[0054] Weigh each raw material according to the mass ratio of the above cyan inkjet printing aqueous ink, and then sequentially add deionized water, water-soluble organic solvent, wetting agent, defoaming agent, and surfactant to the dissolved aqueous solid acrylic resin prepared in step (1), and stir at a speed of 800 - 1500 revolutions per minute for 1 hour to mix evenly; then add the cyan color paste prepared in step (3), and continue to stir at a speed of 800 - 1500 revolutions per minute for 3 hours, and filter to obtain the cyan inkjet printing aqueous ink of this example.

[0055] Example 2

[0056] A magenta inkjet printing aqueous ink, the raw material components of which are calculated by weight and include: 24 parts of magenta color paste, 22 parts of water-soluble organic solvent (including diethylene glycol, isopropyl alcohol, and triethylene glycol monobutyl ether with a mass ratio of 5:4:1), 2.5 parts of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK - 024 defoaming agent from BYK Chemie, 0.5 parts of PEG - 400 surfactant, and 49.7 parts of deionized water.

[0057] The preparation method of the above magenta inkjet printing aqueous ink includes the following steps:

[0058] (1) Dissolution of aqueous solid acrylic resin

[0059] Weigh each raw material according to the weight ratio, including 40 parts of Mitsubishi BR116 aqueous solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (ammonia content not less than 25 wt%), 1.5 parts of ethanolamine, and 0.5 parts of BYK - 024 defoaming agent from BYK Chemie; then put the aqueous solid acrylic resin into deionized water, heat to 80 °C and stir at a speed of 800 - 1500 revolutions per minute; then slowly add ammonia water, ethanolamine, and defoaming agent in sequence, and keep warm for 5 hours to obtain the dissolved aqueous solid acrylic resin.

[0060] (2) Preparation of dispersant

[0061] In a reaction vessel filled with a sufficient amount of dipropylene glycol dimethyl ether, 64.45 parts by weight of 2-vinylnaphthalene, 15.06 parts by weight of acrylic acid, 20.49 parts by weight of maleic anhydride, and 3 parts by weight of benzoyl peroxide are sequentially added to form a reaction system; then the reaction system is placed in a nitrogen atmosphere, stirred continuously, and the temperature is controlled at 90 °C for 5 hours of reaction; after the reaction is completed, the obtained white powder solid is washed clean with toluene, and then added to a sufficient amount of toluene. While stirring, 40 parts by weight of PEG-400 and 3 parts by weight of p-toluenesulfonic acid are added, and the temperature is controlled at 70 °C for 10 hours of reaction; after the reaction is completed, evaporation and purification are carried out to obtain a naphthylethylene-modified acrylic dispersant.

[0062] (3)Preparation of magenta colorant:

[0063] Weigh each raw material according to the weight ratio, including 27 parts by weight of BASF Paliogen Red K 3580 magenta color powder, 63 parts by weight of deionized water, and 10 parts by weight of the dispersant prepared in step (2); then mix the color powder, deionized water, and the dispersant evenly to form a slurry; then grind and filter the slurry to obtain a magenta colorant with a particle size D 97 between 0.26 - 0.27 μm.

[0064] (4)Preparation of ink:

[0065] Weigh each raw material according to the mass ratio of the above magenta inkjet printing aqueous ink, and then sequentially add deionized water, water-soluble organic solvent, wetting agent, defoaming agent, and surfactant to the dissolved aqueous solid acrylic resin prepared in step (1), and stir at a speed of 800 - 1500 revolutions per minute for 1 hour to mix evenly; then add the magenta colorant prepared in step (3), and continue to stir at a speed of 800 - 1500 revolutions per minute for 3 hours, and filter to obtain the magenta inkjet printing aqueous ink of this example.

[0066] Example 3

[0067] A yellow inkjet printing aqueous ink, the raw material components of which are calculated by weight and include: 20 parts by weight of yellow colorant, 22 parts by weight of water-soluble organic solvent (including ethylene glycol, glycerol, and diethylene glycol monobutyl ether with a mass ratio of 7:2:1), 2.5 parts by weight of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts by weight of SURFYNOL 465 wetting agent, 0.3 parts by weight of BYK-018 defoaming agent of BYK Chemie, 0.5 parts by weight of PEG-200 surfactant, and 52.7 parts by weight of deionized water.

[0068] The preparation method of the above inkjet printing aqueous ink includes the following steps:

[0069] (1)Dissolution of aqueous solid acrylic resin

[0070] Weigh each raw material 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 25 wt%), 1.5 parts of ethanolamine, and 0.5 part of BYK-024 defoamer from BYK Chemie; then put the water-based solid acrylic resin into deionized water, heat it to 80 °C and stir at a speed of 800 - 1500 revolutions per minute; then slowly add ammonia water, ethanolamine, and defoamer in sequence, and keep warm for 5 hours to obtain the dissolved water-based solid acrylic resin.

[0071] (2) Preparation of dispersant

[0072] In a reaction vessel filled with sufficient dipropylene glycol dimethyl ether, add 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride, and 3 parts of benzoyl peroxide in sequence according to the weight ratio to form a reaction system; then place the reaction system in a nitrogen atmosphere, keep stirring, control the temperature at 90 °C, and react for 5 hours; after the reaction, wash the obtained white powder solid with toluene, then add it to sufficient toluene, add 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid while stirring, control the temperature at 70 °C, and react for 10 hours; after the reaction, perform evaporation and purification to obtain naphthylethylene-modified acrylic dispersant.

[0073] (3) Preparation of yellow color paste:

[0074] Weigh each raw material according to the weight ratio, including 25 parts of Paliotol Yellow K 2142 yellow color powder, 65 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 and filter the slurry to obtain a yellow color paste with a particle size D 97 between 0.23 - 0.24 μm.

[0075] (4) Preparation of ink:

[0076] Weigh each raw material according to the mass ratio of the above yellow inkjet printing water-based ink, then add deionized water, water-soluble organic solvent, wetting agent, defoamer, and surfactant to the dissolved water-based solid acrylic resin prepared in step (1) in sequence, stir at a speed of 800 - 1500 revolutions per minute for 1 hour to mix evenly; then add the yellow color paste prepared in step (3), continue to stir at a speed of 800 - 1500 revolutions per minute for 3 hours, and filter to obtain the yellow inkjet printing water-based ink of this example.

[0077] Example 4

[0078] A black inkjet printing aqueous ink, the raw material components of which by weight include: 25 parts of black color paste, 22 parts of water-soluble organic solvent (including ethylene glycol, glycerol and diethylene glycol monobutyl ether with a mass ratio of 7:2:1), 2.5 parts of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK-024 defoamer from BYK Chemie, 0.5 parts of PEG-400 surfactant, and 49.7 parts of deionized water.

[0079] The preparation method of the above black inkjet printing aqueous ink includes the following steps:

[0080] (1) Dissolution of aqueous solid acrylic resin

[0081] Weigh each raw material according to the weight ratio, including 40 parts of Mitsubishi BR116 aqueous 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 from BYK Chemie; then put the aqueous solid acrylic resin into deionized water, heat to 80°C and stir at a speed of 800 - 1500 revolutions per minute; then slowly add ammonia water, ethanolamine and defoamer in sequence, and keep warm for 5 hours to obtain the dissolved aqueous solid acrylic resin.

[0082] (2) Preparation of dispersant

[0083] In a reaction vessel filled with sufficient dipropylene glycol dimethyl ether, add 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride, and 3 parts of benzoyl peroxide in sequence according to the weight ratio to form a reaction system; then place the reaction system in a nitrogen atmosphere, keep stirring, control the temperature at 90°C, and react for 5 hours; after the reaction, wash the obtained white powder solid with toluene, then add it to sufficient toluene, add 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid while stirring, control the temperature at 70°C, and react for 10 hours; after the reaction, perform evaporation and purification to obtain naphthylvinyl-modified acrylic dispersant.

[0084] (3) Preparation of black color paste:

[0085] Weigh each raw material 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 form a slurry; then grind and filter the slurry to obtain a black color paste with a particle size D 97 between 0.20 - 0.21 μm.

[0086] (4) Preparation of ink:

[0087] Weigh each raw material according to the mass relationship of the above-mentioned black inkjet printing aqueous ink. Then, successively add deionized water, water-soluble organic solvent, wetting agent, defoaming agent, and surfactant to the dissolved aqueous solid acrylic resin prepared in step (1), and stir at a speed of 800 - 1500 revolutions per minute for 1 hour to mix evenly; then add the black color paste prepared in step (3), and continue to stir at a speed of 800 - 1500 revolutions per minute for 3 hours. After filtration, the black inkjet printing aqueous ink of this example is obtained.

[0088] Example 5

[0089] A white inkjet printing aqueous ink, the raw material components of which by weight include: 25 parts of white color paste, 17 parts of water-soluble organic solvent (including ethylene glycol, glycerol, and diethylene glycol monobutyl ether with a mass ratio of 7:2:1), 3 parts of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 part of BYK-018 defoaming agent from BYK Chemie, 0.5 part of PEG-400 surfactant, and 52.2 parts of deionized water.

[0090] The preparation method of the above-mentioned white inkjet printing aqueous ink includes the following steps:

[0091] (1) Dissolution of aqueous solid acrylic resin

[0092] Weigh each raw material according to the weight relationship, including 40 parts of Mitsubishi BR116 aqueous solid acrylic resin, 50 parts of deionized water, 8 parts of ammonia water (ammonia content not less than 25 wt%), 1.5 parts of ethanolamine, and 0.5 part of BYK-018 defoaming agent from BYK Chemie; then put the aqueous solid acrylic resin into deionized water, heat to 80 °C and stir at a speed of 800 - 1500 revolutions per minute; then successively and slowly add ammonia water, ethanolamine, and defoaming agent, and keep warm for 5 hours to obtain the dissolved aqueous solid acrylic resin.

[0093] (2) Preparation of dispersant

[0094] In a reaction vessel filled with sufficient dipropylene glycol dimethyl ether, successively add 64.45 parts of 2-vinylnaphthalene, 15.06 parts of acrylic acid, 20.49 parts of maleic anhydride, and 3 parts of benzoyl peroxide according to the weight relationship to form a reaction system; then place the reaction system in a nitrogen atmosphere, keep stirring, control the temperature at 90 °C, and react for 5 hours; after the reaction is completed, wash the obtained white powder solid with toluene, and then add it to sufficient toluene. While stirring, add 40 parts of PEG-400 and 3 parts of p-toluenesulfonic acid, control the temperature at 70 °C, and react for 10 hours; after the reaction is completed, carry out evaporation and purification to obtain the naphthylvinyl-modified acrylic dispersant.

[0095] (3) Preparation of white pigment paste:

[0096] Weigh each raw material 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 the dispersant evenly to form a slurry; then grind and filter the slurry to obtain a white pigment paste with a particle size D 97 between 0.50 - 0.60 μm.

[0097] (4) Preparation of ink:

[0098] Weigh each raw material according to the mass ratio of the above white inkjet printing aqueous ink, and then sequentially add deionized water, water-soluble organic solvent, wetting agent, defoaming agent, and surfactant to the dissolved aqueous solid acrylic resin prepared in step (1), and stir at a speed of 800 - 1500 revolutions per minute for 1 hour to mix evenly; then add the white pigment paste prepared in step (3), and continue to stir at a speed of 800 - 1500 revolutions per minute for 3 hours, and filter to obtain the white inkjet printing aqueous ink of this example.

[0099] Comparative Example 1

[0100] The difference between Comparative Example 1 and Example 5 is only in the raw material components of the white inkjet printing aqueous ink. 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.

[0101] Comparative Example 2

[0102] The difference between Comparative Example 2 and Example 5 is only in the raw material components of the white inkjet printing aqueous ink. The raw material components of the white inkjet printing aqueous ink in Comparative Example 2 include, by weight: 25 parts of white pigment paste, 17 parts of water-soluble organic solvent (including ethylene glycol, glycerol, and diethylene glycol monobutyl ether with a mass ratio of 7:2:1), 5 parts of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK-018 defoaming agent from BYK Chemie, 0.5 parts of PEG-400 surfactant, and 50.2 parts of deionized water.

[0103] Comparative Example 3

[0104] The difference between Comparative Example 3 and Example 5 lies only in the different raw material components of the white inkjet printing aqueous ink. The raw material components of the white inkjet printing aqueous ink in Comparative Example 3 include, by weight: 25 parts of white color paste, 25 parts of water-soluble organic solvent (including ethylene glycol, glycerol, and diethylene glycol monobutyl ether with a mass ratio of 7:2:1), 3 parts of Mitsubishi BR116 aqueous solid acrylic resin, 2 parts of SURFYNOL 465 wetting agent, 0.3 parts of BYK-018 defoamer from BYK Chemie, 0.5 parts of PEG-400 surfactant, and 44.2 parts of deionized water.

[0105] Comparative Example 4

[0106] The difference between Comparative Example 4 and Example 5 lies only in the different raw materials for preparing the white color paste. In Comparative Example 4, an equal amount of the aqueous styrene-acrylic copolymer emulsion dispersant Acronal Proof 1108 AP from BASF, Germany, is used to replace the naphthylstyrene-modified acrylic dispersant prepared in step (2) of Example 5.

[0107] Performance Test

[0108] Perform performance tests on the inkjet printing aqueous ink samples prepared in the above Examples 1-5 and Comparative Examples 1-4. Specifically, use a viscometer to measure the viscosity of the ink, a surface tension meter to measure the surface tension of the ink, an Omec laser particle size analyzer to measure the ink particle size D 50 and D 97 , and use a Mettler FE38 to measure the conductivity of the ink.

[0109] For the drying time, use a 10 μm film applicator to scrape the ink flat on a PET substrate, and then use a stopwatch to record the time required for drying.

[0110] The adhesion fastness is determined with reference to the national standard GB / T 13217.7-2009 "Test Method for Adhesion Fastness of Liquid Ink".

[0111] The process for testing the inkjet printing fluidity is as follows: Continuously print 100 m of the ink with an inkjet printer, and perform a nozzle check without cleaning, and observe the number of ink breakage holes on the status bar.

[0112] The process for testing the sedimentation situation is as follows: Fill a 10 mL test tube with the inkjet printing aqueous ink and let it stand for two months, observe whether there is stratification and sedimentation, record the volume of the supernatant after stratification, and the sedimentation rate = volume of supernatant / (10 mL).

[0113] The lightfastness is determined with reference to the national standard GB1710-79 "Method for Determining Lightfastness of Pigments". Among them, the lightfastness grade is divided into grades 1 to 8, and grade 1 has the worst lightfastness and grade 8 has the best lightfastness.

[0114] The test results are shown in Table 1.

[0115] Table 1:

[0116]

[0117] From the test results in Table 1, it can be seen that in Examples 1 - 5, by adding a certain amount of aqueous solid acrylic resin and dispersing the toner with a specific naphthalene - styrene modified acrylic dispersant, and at the same time controlling the dosage relationship between the resin and the water - soluble organic solvent, as well as between the water - soluble organic solvent and deionized water, the prepared ink - jet printing aqueous ink not only has excellent stability, fast drying speed when printed on the substrate, good adhesion, which can greatly improve the production efficiency and quality of composite film flexible packaging, but also the ink itself shows good printing performance, with relatively appropriate viscosity and surface tension, good effect during the ink - jet printing process, no nozzle clogging, and very few or even no broken holes in the printed pattern; moreover, it has a good service life, with a low sedimentation rate of the ink in two months, and good light - fastness.

[0118] By comparing the performance of the ink - jet printing aqueous inks prepared in Comparative Examples 1 - 4 with that in Example 5, it can be seen that the selection of the resin and the dispersant, as well as the dosage relationship between the resin, the water - soluble organic solvent and deionized water, have great influences on the ink performance and printing quality.

[0119] Among them: In Comparative Example 1, due to the use of styrene - acrylic copolymer resin emulsion, it is impossible to have the high molecular weight of solid acrylic resin, resulting in the ineffective adhesion of the ink filler on the flexible packaging material, easy detachment of the printed image, and poor light - fastness and stability of the ink. At the same time, the resin emulsion is greatly affected by the emulsifier, seriously affecting the ink stability, causing the ink to stratify or precipitate during long - term storage and use, thus affecting the continuity of printing.

[0120] In Comparative Example 2, the content of the aqueous solid acrylic resin is too high, resulting in an increase in the viscosity of the ink, and then a decrease in the fluidity of the ink in the nozzle or the formation of ink droplets, thus causing nozzle clogging, manifested as many broken holes in printing, affecting the production efficiency of flexible packaging. Moreover, too much resin in the ink will slow down the drying speed, resulting in blurred images due to the ink not being dry during high - speed printing in production.

[0121] In Comparative Example 3, the content of the water - soluble organic solvent is too high. On the one hand, it leads to too high viscosity of the ink, affecting the printing fluency of the ink and at the same time slowing down the drying speed of the ink, affecting high - speed printing in production; on the other hand, it causes a decrease in the ink life because too much organic solvent causes the resin component in the ink composition to decompose or swell, etc., damaging its own performance and resulting in a decrease in the ink life.

[0122] Comparative Example 4 uses a dispersant imported from abroad. The main chain of the dispersant adopts a benzene ring structure. Compared with the naphthalene ring structure of the present invention, the basic properties of the prepared ink are comparable, but there are problems of poor long-term stability, as well as poor adhesion and light resistance.

[0123] In summary, by using water-based solid acrylic resin and a specific naphthylstyrene-modified acrylic dispersant as the main raw materials and controlling the dosage relationship between the raw materials, the inkjet printing water-based ink prepared by the present invention not only has good inkjet printing performance and high lifespan, but also has excellent characteristics such as quick drying, good abrasion resistance and weather resistance, which has important progressive significance for the production of the flexible packaging industry.

[0124] For those of ordinary skill in the art to which the present invention pertains, several simple deductions or substitutions can be made without departing from the concept of the present invention without the need for creative labor. Therefore, simple improvements made 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 the preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made thereto shall fall within the protection scope of the present invention.

Claims

1. A composite film soft package, characterized in that, The composite film soft package includes a plastic film and a pattern layer attached to the surface of the plastic film, and the pattern layer is printed with an inkjet printing aqueous ink; The raw material components of the inkjet printing aqueous ink include, by weight: 15-30 parts of color paste, 15-25 parts of water-soluble organic solvent, 2-3 parts of aqueous solid acrylic resin, 40-60 parts of deionized water, and 2-5 parts of additives; the additives include a wetting agent, an antifoaming agent, and a surfactant, and the surfactant is polyethylene glycol; the aqueous solid acrylic resin is Mitsubishi BR116; The mass ratio of the aqueous solid acrylic resin to the water-soluble organic solvent is 1:(5-10), and the mass ratio of the water-soluble organic solvent to the deionized water is 1:(2-4); the color paste contains color powder and a dispersant, and the dispersant is a naphthyl ethylene modified acrylic dispersant; The preparation process of the naphthyl ethylene modified acrylic dispersant is as follows: 2-vinylnaphthalene, acrylic acid, maleic anhydride, and benzoyl peroxide are added to an organic solvent, and the reaction is carried out under a nitrogen atmosphere; then the solid reaction product is washed with toluene and added to toluene, and stirred; then polyethylene glycol and p-toluenesulfonic acid are added, and the reaction is continued; after evaporation and purification, the naphthyl ethylene modified acrylic dispersant is obtained; the raw materials for preparing the naphthyl ethylene 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.

2. The composite film soft package 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.

3. The composite film soft package 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 and 0.6 μm.

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