Water-based ink with barrier properties and process for its preparation

Abstract

The application discloses a water-based ink with barrier property and a preparation process thereof, and relates to the technical field of water-based ink. The water-based ink comprises the following components: modified acrylic resin, pigment, montmorillonite, polyester dispersant, acetylenic diol wetting agent, organic silicon composite defoaming agent, low-viscosity modified siloxane leveling agent, aziridine crosslinking agent, and the rest is deionized water; wherein the modified acrylic resin is grafted with perfluorobutyl, glycidyl ether oxy and hydroxyl on a molecular chain, the particle size of the montmorillonite is less than 500 nm, and the diameter-thickness ratio is greater than 50. The preparation process comprises the following steps: nanoclay pre-activation and pigment dispersion, reactive dispersion and resin grafting, low-temperature grinding and directional curing. In the ink formula, the modified acrylic resin is matched with a high-activity aziridine crosslinking agent and a sheet-shaped nanoclay filler, synergistic effect is achieved through specific formula proportion, the comprehensive barrier property of the ink is significantly improved, and the OTR is reduced to 4.2 cc / m2·day.

Description

Technical Field

[0001] This invention relates to the field of inks, and more specifically to a water-based ink with barrier properties and its preparation process. Background Technology

[0002] With increasing environmental awareness, water-based inks are gradually replacing solvent-based inks in the packaging materials field, such as for food and pharmaceuticals. However, traditional water-based inks have the following shortcomings in terms of barrier performance: food packaging standards require an oxygen translucency (OTR) of <5 cc / m²·day, a water vapor transmission rate (WVTR) of <5 g / m²·day, and grease barrier performance that requires no penetration for 72 hours; while traditional water-based inks have an OTR of 15~20 cc / m²·day and a WVTR of 8~12 g / m²·day, and grease penetration occurs after 24 hours, making it difficult to meet the high barrier performance requirements of food and pharmaceutical packaging materials.

[0003] The main reasons for the weak barrier properties of traditional water-based inks are: poor film density, with water as a dispersion medium causing a 30%-40% reduction in the entanglement of resin molecular chains; weak interfacial bonding, with adhesion on PE / PP substrates of only 3-4B (cross-cut test), lower than the 5B of solvent-based inks; and insufficient weather resistance, with barrier properties decreasing by up to 50% after accelerated aging at 60℃ / 75%RH.

[0004] Existing technologies for improving the barrier properties of water-based inks mainly include: adding inorganic nanomaterials, such as nano-silica and nano-alumina, but these methods suffer from poor dispersibility and easy agglomeration, affecting ink performance; adding organic barrier agents, such as polyvinyl alcohol and polyvinylidene chloride, but these methods suffer from poor compatibility with water-based resins and affect the printability of the ink; and multilayer composite structures, which improve barrier properties by coating multiple layers of inks with different functions, but these methods are complex and costly. Summary of the Invention

[0005] The purpose of this invention is to provide a water-based ink with barrier properties and its preparation process, which improves the problem of insufficient barrier properties of existing water-based inks by using a process of split-stripping-pre-crosslinking protection-directional final curing.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A water-based ink with barrier properties, comprising the following components by weight percentage:

[0008] Modified acrylic resin: 30-50%; Pigment: 10-20%; Montmorillonite: 5-15%; Polyester dispersant: 1-3%; Acrylylene diol wetting agent: 0.5-2%; Organosilicon composite defoamer: 0.1-0.5%; Low viscosity modified siloxane leveling agent: 0.1-0.5%; Aziridine crosslinking agent: 2-5%; Balance: deionized water;

[0009] The modified acrylic resin has perfluorobutyl, glycidyl etheroxy and hydroxyl groups grafted onto its molecular chain, and the montmorillonite has a particle size of less than 500 nm and an aspect ratio of >50.

[0010] The modified acrylic resin of this invention is grafted with perfluorobutyl groups, providing excellent low surface energy and forming a fluorinated brush structure on the acrylic resin surface with a contact angle >110°, giving the coating water and oil repellency, reducing the adsorption and penetration of water, oil, and other substances. The grafted glycidyl ether oxygen groups provide reactive sites, enhancing adhesion to the substrate. More importantly, they can react efficiently with aziridine crosslinking agents, achieving efficient and rapid crosslinking and curing, forming a three-dimensional network structure with high crosslinking density. High crosslinking density can effectively reduce free volume and block the diffusion and penetration of small molecules (such as water vapor and oxygen); the grafted hydroxyl groups enhance water dispersibility and prevent demulsification in compound formulations. This solution combines both on the same resin molecular chain. This bifunctional group setting produces a synergistic effect: fluorinated segments tend to migrate and enrich towards the coating surface, providing a durable low surface energy barrier; epoxy groups mainly participate in crosslinking inside the coating, constructing a dense network framework; the combination of the two can simultaneously construct a barrier layer on the coating surface and inside, overcoming the limitations that may exist with single modification.

[0011] Montmorillonite particles with a diameter < 500 nm and an aspect ratio > 50 are nanosheetized using a peel-and-recombination technique, allowing for directional arrangement during ink film formation and extending the oxygen permeation path. Traditional water-based inks have an OTR > 15 cc / m²·day, which cannot meet the packaging requirements for products like milk powder (requiring < 5 cc / m²·day). In this invention, montmorillonite nanosheets provide oxygen barrier properties, while fluorine brushes work synergistically to block water, reducing the OTR to 4.2 cc / m²·day, a 300% improvement in barrier properties compared to pure resin coatings. Solvent-based inks offer excellent barrier properties but have VOCs > 300 g / L, while traditional water-based inks have VOCs < 50 g / L but poor barrier properties. This invention has VOCs < 30 g / L and barrier performance comparable to solvent-based inks. High-barrier inks require high-temperature baking (> 120°C), making them unsuitable for heat-sensitive substrates like PET. This invention uses aziridine-based crosslinking agents for room-temperature crosslinking, enabling room-temperature curing. This invention resolves the conflict between barrier properties and water-based properties through fluorine / silicon / hydroxyl ternary grafting; it also utilizes high aspect ratio montmorillonite to achieve directional arrangement during ink film formation, breaking through the penetration threshold of nanofillers.

[0012] The content range of each component in this invention has also been carefully considered. The resin content (30-50%) ensures sufficient continuous film formation; the filler (5-15%) provides barrier properties while avoiding excessive amounts that would lead to poor rheology and reduced gloss; the crosslinking agent (2-5%) needs to be sufficient to allow the epoxy groups to react effectively and form a network, while too much may increase costs or affect flexibility.

[0013] This invention simultaneously introduces fluorinated groups (perfluorobutyl), epoxy groups (glycidyl etheroxy) and hydroxyl groups to modify acrylic resin, and uses highly active aziridine crosslinking agents and sheet-like nano clay fillers (montmorillonite) in a specific formulation ratio to achieve synergistic effects and significantly improve the overall barrier properties of ink.

[0014] Furthermore, the pigment is selected from either composite titanium red or resinized phthalocyanine blue; the aziridine crosslinking agent is trimethylolpropane tris(2-methylaziridine)propionate.

[0015] A preparation process applicable to the aforementioned water-based ink with barrier properties includes the following steps:

[0016] S100. Add the filler, 45-55% of the total amount of wetting agent, and 25-35% of the total amount of dispersant to 35-45% of the total amount of deionized water. Sonicate at 55-65℃ for 28-32 minutes to fully peel off the filler and form a pre-activated slurry with a fineness of <5μm. In a separate container, mix the pigment, defoamer, and remaining dispersant with 15-25% of the total amount of deionized water and pre-disperse by high-speed shearing to obtain a concentrated pigment slurry.

[0017] S200: Add the modified acrylic resin to the pre-activated slurry from step S100, heat to 72~78℃, slowly add 45~55% crosslinking agent, and react for 0.8~1.2h.

[0018] Cool the reaction system to 38~42℃ at a rate of ≤5℃ / min, add 20~35% deionized water, then add the pigment concentrate, leveling agent and remaining wetting agent from step S100, stir evenly, add the remaining deionized water, stir at low speed for 18~22min, mix evenly, and obtain a mixed slurry.

[0019] S300: Grind the mixture from step S200 at a temperature of ≤35℃ until the fineness is <5μm; immediately after grinding, add the remaining crosslinking agent, then add ammonia water, adjust the pH to 8.2~8.6, stir at low speed for 8~12 minutes, and then filter to obtain the target product.

[0020] In step S100, montmorillonite is not ultrasonically treated simultaneously with the pigment to avoid pigment interference and decomposition. Hydraulic shearing is used to peel off the layered structure, resulting in a thickness-to-diameter ratio > 50, effectively improving peeling efficiency and barrier properties. High-speed shearing of the pigment effectively breaks down agglomerates, achieving a fineness < 5 μm. In step S200, at a high temperature of 72-78℃, 45-55% of the crosslinking agent pre-reacts with the resin-clay composite to form anchor crosslinking points, preventing a sudden increase in viscosity due to concentrated crosslinking later. The nano-clay becomes the crosslinking network node, improving coating density and increasing oxygen barrier properties by 30%. Glycidyl ether oxygen preferentially reacts with aziridine crosslinking agents to form a dense crosslinked shell on the resin surface, preventing subsequent filler incorporation from damaging the network. In step S300, after the temperature is reduced to ≤35℃, the remaining crosslinking agent is added to prevent high-temperature migration of fluorine chains, reducing the attenuation rate of the contact angle from 118° to 105° to <3%. After pre-crosslinking of the filler / resin, grinding is performed, and shear force is used to orient the montmorillonite sheets into parallel arrangements. The fineness <5μm ensures that the montmorillonite has no stacked pores, the oxygen permeation path is extended to twice that of the traditional method, and the OTR is reduced from 8.5cc / m²·day to 4.2 cc / m²·day. The pH is 8.2~8.6, which can inhibit the hydrolysis of aziridine, and the viscosity increase is <10% after 30 days of storage at 50℃.

[0021] The ink preparation process of this invention, with montmorillonite stripping and pigment dispersion pathway treatment, can balance high aspect ratio and color stability; 45-55% crosslinking agent high-temperature pre-reaction to construct a resin protective shell layer, provides a low-temperature and high-efficiency mass production process for high-barrier water-based inks.

[0022] Further, in step S100, the ultrasonic power is 40kHz, the high-speed shearing speed is 4500~5500rpm, and the time is 12~18min; in step S200, the cooling rate is ≤5℃ / min; and the low-speed stirring speed is 200~300rpm.

[0023] Furthermore, the preparation process of the modified acrylic resin, by weight, includes the following raw materials:

[0024] MMA: 35-45 parts, BA: 25-35 parts, HEA: 10-15 parts; SDS: 1.0-1.5 parts, emulsifier OP-10: 0.8-1.2 parts; APS: 0.8-1.2 parts; polymerization inhibitor hydroquinone: 0.01-0.02 parts; sodium bicarbonate: 0.1-0.3 parts; deionized water: 120-150 parts; KH-560: 6-8 parts; tetraisopropyl titanate: 0.1-0.3 parts; PFBMA: 20-25 parts; CuBr: 4-5 parts; PMDETA: 10-12 parts; perfluoropolyether surfactant: 7-8 parts; KH-570 modified nano-SiO2: 2-4 parts; E-513: 5 parts.

[0025] Furthermore, the preparation process of the modified acrylic resin includes the following steps:

[0026] Step 1: Dissolve 28-32% of SDS and NaHCO3 buffer in 20-25% of deionized water, heat to 78-82℃, and purge with nitrogen for 14-16 min; add 29-31% of APS initiator and stir at low speed; add 9-11% of pre-emulsion at a rate of 1 ml / min, keep warm at 79-81℃, and react for 28-32 min.

[0027] Step 2: Dissolve the remaining initiator APS in the remaining deionized water to prepare a solution. Add the remaining pre-emulsion and initiator APS solution dropwise to the solution obtained in Step 2 at a rate of 2 mL / min, and control the temperature at 78~82℃. 28~32 min before the remaining pre-emulsion is completely added, cool down to 74~76℃, add HEA, and mix rapidly for 8~12 min.

[0028] Step 3: Cool down to 60℃, add KH-560 in 3 batches with an interval of 18~22 min between each batch, add sodium bicarbonate, adjust the pH to 6.5~7.5, then add a 5% ethanol solution of tetraisopropyl titanate, and keep the reaction at the temperature for 2.8~3.2h; after post-treatment, obtain the dried resin intermediate product.

[0029] Step 4: Add the intermediate product obtained in Step 3, 2-bromoisobutyryl bromide, and triethylamine to a mixed solvent of THF and water, and react at 58-62°C under N2 protection for 1.8-2.2 h; cool to 48-52°C, add PFBMA, CuBr, and PMDETA, and react under N2 protection for 11.5-12.5 h; stop the reaction by purging with air, and add a perfluoropolyether surfactant.

[0030] Step 5: Add the pre-dispersed KH-570 modified nano-SiO2 to the solution obtained in Step 4 and stir until homogeneous; heat to 74~76℃, add bisphenol A epoxy resin E-51, and stir for 1 h; cool to 35~40℃, adjust the pH to 7.5-8.0 with ammonia water, filter through a 180~200 mesh screen to obtain modified acrylic resin.

[0031] This invention pre-emulsifies 65-75% HEA, then adds the remaining 25-35% HEA later, enriching the surface of latex particles with hydroxyl groups, increasing the surface hydroxyl density by 40% and improving the grafting rate of KH-560 to 92%. Grafting glycidyl ether oxygen groups first, followed by perfluorobutyl groups, avoids interference from siloxane hydrolysis with ATRP, increasing the fluorine grafting rate to 94.1% and solving the phase separation problem. Nano-SiO2 is added in the post-crosslinking stage; SiO2 is anchored by the reaction of Si-OH with epoxy groups, improving barrier properties by 50%. Anionic emulsifier SDS is used in the seed stage for precise particle size control. Nonionic emulsifier OP-10 is added in the main polymerization stage to improve the inclusion of fluorine / silicone monomers and prevent gel formation. This invention solves the phase separation problem in the synthesis of multifunctional resins through delayed addition of functional monomers and synergistic temperature / emulsifier regulation, while also meeting the operability requirements for industrial production.

[0032] Further, in step 1, the preparation process of the pre-emulsion includes the following: MMA, BA, and 65-75% HEA (total amount) are premixed, and then added to 55-65% deionized water along with 68-72% SDS, emulsifier OP-10, and hydroquinone (total amount). The mixture is stirred at low speed for 30 minutes at 15-25°C to obtain the pre-emulsion. In step 2, the mass of HEA added is 25-35% of the total mass of HEA.

[0033] Further, in step 3, the post-processing method includes the following: cooling to below 25°C, adding 5% CaCl2 solution and stirring for 15 min, centrifuging for 8-12 min to obtain the middle layer resin flocculent; washing the resin flocculent with an acetone-water mixed solvent 2-3 times at 60°C, and vacuum drying at 60-62°C for 23-24 h, with a water content of <0.1% after drying; the volume ratio of acetone to water is 1-2:1; the mass of the added 5% CaCl2 accounts for 4.9-5.1% of the total mass of the emulsion after the reaction in step 3.

[0034] CaCl2 demulsification precision control (4.9~5.1%): compresses the double electric layer without destroying the fluorine chain, resulting in a resin yield >98%.

[0035] Further, in step 4, the mass ratio of intermediate product, 2-bromoisobutyryl bromide, and triethylamine is 1:0.28~0.32:0.50~0.55; the resin intermediate product and THF are prepared with a solid content of 10%, and the volume ratio of THF to water is 2.2~2.5:1.

[0036] The aqueous phase promotes the Cu⁺ / Cu²⁺ cycle, and THF dissolves the fluorine monomer, resulting in a grafting efficiency of 92%.

[0037] Furthermore, the method for pre-dispersing KH-570 modified nano-SiO2 is characterized by: controlling the temperature in an ice-water bath to ≤30℃, ultrasonically dispersing KH-570 modified nano-SiO2 in propylene glycol methyl ether for 20~30 min, the ultrasonic dispersion power being 300~400 W, and the mass ratio of KH-570 modified nano-SiO2 to propylene glycol methyl ether being 1:8~12.

[0038] Beneficial effects of the invention

[0039] 1. The ink formulation of this invention simultaneously introduces fluorinated groups (perfluorobutyl), epoxy groups (glycidyl etheroxy), and hydroxyl groups to modify acrylic resin, and uses highly active aziridine crosslinking agents and flake-like nano-clay fillers (montmorillonite) in matching ratios to achieve synergistic effects, significantly improving the overall barrier properties of the ink and significantly reducing OTR. This invention provides a water-based ink solution for food and pharmaceutical packaging with VOC < 30 g / L and OTR < 4.2 cc / m²·day, which can promote the green development of the packaging industry.

[0040] 2. The ink preparation process of the present invention, with montmorillonite stripping and pigment dispersion through separate pathways, can balance high aspect ratio and color stability; 45~55% crosslinking agent is pre-reacted at high temperature to construct a resin protective shell layer, providing a low-temperature and high-efficiency mass production process for high-barrier water-based inks.

[0041] 3. The preparation process of the modified acrylic resin of the present invention breaks through the fluorosilicone compatibility barrier, with a grafting rate >92%; it achieves high-efficiency ATRP in a water-based system, with a fluorine grafting rate of 93.5% and VOC <28 g / L; it provides a resin synthesis solution for food packaging inks that combines super barrier properties with extreme environmental protection.

[0042] MMA: Methyl methacrylate;

[0043] BA: Butyl acrylate;

[0044] HEA: Hydroxyethyl acrylate;

[0045] SDS: Sodium dodecyl sulfate;

[0046] E-51: Bisphenol A type epoxy resin;

[0047] KH-560: γ-glycidoxypropyltrimethoxysilane;

[0048] PFBMA: Perfluorobutyl methacrylate;

[0049] PMDETA: Pentamethyldiethylenetriamine;

[0050] APS: Ammonium persulfate;

[0051] THF: Tetrahydrofuran. Detailed Implementation

[0052] Example 1

[0053] The preparation process of the modified acrylic resin includes the following raw materials:

[0054] MMA: 400g; BA: 300g; HEA: 120g; SDS: 12g; Emulsifier OP-10: 10g; APS: 10g; Polymerization inhibitor hydroquinone: 0.15g; Sodium bicarbonate: 2g; Deionized water: 1350g; KH-560: 70g; Tetraisopropyl titanate: 2g; PFBMA: 230g; CuBr: 45g; PMDETA: 110g; Surfactant Capstone FS-3100: 75g; KH-570 modified nano-SiO2: 30g; E-5140g.

[0055] The preparation process of the modified acrylic resin includes the following steps:

[0056] Step 1: Dissolve 3.6g of SDS and buffer NaHCO3 in 310g of deionized water, heat to 80℃, and purge with nitrogen for 15min; add 3g of initiator APS and stir at low speed; add 10% of the total amount of pre-emulsion at a rate of 1ml / min, keep warm at 80℃, and react for 30min.

[0057] The preparation process of the pre-emulsion includes the following: 400g MMA, 300g BA and 84g HEA are premixed and then added to 810g deionized water along with 8.4g SDS, 10g emulsifier OP-10 and 0.15g hydroquinone. The mixture is stirred at low speed for 30min at 20℃ to obtain the pre-emulsion.

[0058] Step 2: Dissolve the remaining initiator APS in the remaining deionized water to prepare a solution. Add the remaining pre-emulsion and initiator APS solution dropwise to the solution obtained in Step 2 at a rate of 2 mL / min, and control the temperature at 80℃. 30 min before the remaining pre-emulsion is completely added, cool down to 75℃, add 36 g HEA, and mix rapidly for 10 min.

[0059] Step 3: Cool down to 60℃, add KH-560 in 3 batches with an interval of 20 min between each batch, add sodium bicarbonate, adjust the pH to 7, then add 5% ethanol solution of tetraisopropyl titanate, keep the reaction at the temperature for 3 hours; after post-treatment, obtain the dried resin intermediate product.

[0060] The post-processing method includes the following: cooling to below 25℃, adding 5% CaCl2 solution and stirring for 15 min, centrifuging for 10 min to obtain the middle layer resin flocculent; washing the resin flocculent three times with a mixed solvent of 15 L acetone and 10 L water at 60℃, and vacuum drying at 61℃ for 24 h; the mass of the added 5% CaCl2 accounts for 5.0% of the total mass of the emulsion after the reaction in step 3.

[0061] Step 4: Take 500g of the intermediate product obtained in Step 3, 150g of 2-bromoisobutyryl bromide, and 260g of triethylamine and add them to 6457mL of a mixed solvent of THF and water. React at 60℃ under N2 protection for 2h. Cool down to 50℃, add 230g of PFBMA, 45g of CuBr, and 110g of PMDETA. React under N2 protection for 12h. Stop the reaction by purging air and add 75g of perfluoropolyether surfactant.

[0062] The resin intermediate product and THF were prepared with a solid content of 10% and the volume ratio of THF to water was 2.3:1.

[0063] Step 5: Add the pre-dispersed KH-570 modified nano-SiO2 to the solution obtained in Step 4 and stir until homogeneous; heat to 75℃, add 40g of bisphenol A epoxy resin E-51, and stir for 1 h; cool to 38℃, adjust the pH to 7.6 with ammonia water, filter through a 200-mesh filter to obtain modified acrylic resin.

[0064] The pre-dispersion method of KH-570 modified nano-SiO2 includes: controlling the temperature in an ice-water bath at 30℃, ultrasonically dispersing 30g of KH-570 modified nano-SiO2 in 300g of propylene glycol methyl ether for 25 min, with an ultrasonic dispersion power of 350W.

[0065] Example 2

[0066] The preparation process of the modified acrylic resin includes the following raw materials:

[0067] MMA: 350g; BA: 250g; HEA: 100g; SDS: 10g; Emulsifier OP-10: 8g; APS: 8g; Polymerization inhibitor hydroquinone: 0.1g; Sodium bicarbonate: 1g; Deionized water: 1200g; KH-560: 60g; Tetraisopropyl titanate: 1g; PFBMA: 200g; CuBr: 40g; PMDETA: 100g; Surfactant Capstone FS-3100: 70g; KH-570 modified nano-SiO2:

[0068] 20g; E-5130g.

[0069] The preparation process of the modified acrylic resin includes the following steps:

[0070] Step 1: Dissolve 2.8g of SDS and buffer NaHCO3 in 300g of deionized water, heat to 78℃, and purge with nitrogen for 14min; add 2.3g of initiator APS and stir at low speed; add 9% of the total amount of pre-emulsion at a rate of 1ml / min, keep warm at 79℃, and react for 28min.

[0071] The preparation process of the pre-emulsion includes the following: 350g of MMA, 250g of BA and 65g of HEA are premixed and then added to 780g of deionized water along with 7.2g of SDS, 8g of emulsifier OP-10 and 0.1g of hydroquinone. The mixture is stirred at low speed for 30min at 15℃ to obtain the pre-emulsion.

[0072] Step 2: Dissolve the remaining initiator APS in the remaining deionized water to prepare a solution. Add the remaining pre-emulsion and initiator APS solution dropwise to the solution obtained in Step 2 at a rate of 2 mL / min, and control the temperature at 78℃. 28 min before the remaining pre-emulsion is completely added, cool down to 74℃, add 35 g HEA, and mix rapidly for 8 min.

[0073] Step 3: Cool down to 60℃, add KH-560 in 3 batches with an interval of 18 min between each batch, add sodium bicarbonate, adjust the pH to 6.5, then add a 5% ethanol solution of tetraisopropyl titanate, and keep the reaction at the temperature for 2.8 h; after post-treatment, a dry resin intermediate product is obtained.

[0074] The post-treatment method includes the following: cooling to below 25℃, adding 5% CaCl2 solution and stirring for 15 min, centrifuging for 8 min to obtain the middle layer resin flocculent; washing the resin flocculent twice with a mixed solvent of 12 L acetone and 12 L water at 60℃, and vacuum drying at 60℃ for 23 h; the mass of the added 5% CaCl2 accounts for 4.9% of the total mass of the emulsion after the reaction in step 3.

[0075] Step 4: Take 500g of the intermediate product obtained in Step 3, 140g of 2-bromoisobutyryl bromide, and 250g of triethylamine and add them to 6928mL of a mixed solvent of THF and water. React at 58℃ under N2 protection for 1.8h. Cool down to 48℃, add 200g of PFBMA, 40g of CuBr, and 100g of PMDETA. React under N2 protection for 11.5h. Stop the reaction by purging air and add 70g of perfluoropolyether surfactant.

[0076] The resin intermediate was prepared with THF at a solid content of 9.5%, and the volume ratio of THF to water was 2.2:1.

[0077] Step 5: Add the pre-dispersed KH-570 modified nano-SiO2 to the solution obtained in Step 4 and stir until homogeneous; heat to 74℃, add bisphenol A epoxy resin E-51, and stir for 0.9 h; cool to 35℃, adjust pH to 7.5 with ammonia water, filter through a 180-mesh filter to obtain modified acrylic resin.

[0078] The pre-dispersion method of KH-570 modified nano-SiO2 includes: controlling the temperature in an ice-water bath at 25℃, ultrasonically dispersing 20g of KH-570 modified nano-SiO2 in 160g of propylene glycol methyl ether for 20 min, with an ultrasonic dispersion power of 300W.

[0079] Example 3

[0080] The preparation process of the modified acrylic resin includes the following raw materials:

[0081] MMA: 450g, BA: 350g, HEA: 150g; SDS: 15g, emulsifier OP-10: 12g; APS: 12g; polymerization inhibitor hydroquinone: 0.2g; sodium bicarbonate: 3g; deionized water: 1500g; KH-560: 80g; tetraisopropyl titanate: 3g; PFBMA: 250g; CuBr: 50g; PMDETA: 120g; surfactant Capstone FS-3100: 80g; KH-570 modified nano-SiO2: 40g; E-5150g.

[0082] The preparation process of the modified acrylic resin includes the following steps:

[0083] Step 1: Dissolve 4.8g of SDS and buffer NaHCO3 in 525g of deionized water, heat to 82℃, and purge with nitrogen for 16min; add 3.7g of initiator APS and stir at low speed; add 11% of the total amount of pre-emulsion at a rate of 1ml / min, keep warm at 81℃, and react for 32min.

[0084] The preparation process of the pre-emulsion includes the following: MMA, BA and 112.5g HEA are premixed, and then 10.2g SDS, emulsifier OP-10 and hydroquinone are added to 825g deionized water. The mixture is stirred at low speed for 30min at 25℃ to obtain the pre-emulsion.

[0085] Step 2: Dissolve the remaining initiator APS in the remaining deionized water to prepare a solution. Add the remaining pre-emulsion and initiator APS solution dropwise to the solution obtained in Step 2 at a rate of 2 mL / min, and control the temperature at 82℃. 32 min before the remaining pre-emulsion is completely added, cool down to 76℃, add HEA, and mix rapidly for 12 min.

[0086] Step 3: Cool down to 60℃, add KH-560 in 3 batches with an interval of 22 min between each batch, add sodium bicarbonate, adjust the pH to 7.5, then add a 5% ethanol solution of tetraisopropyl titanate, and keep the reaction at the temperature for 3.2 h; after post-treatment, a dry resin intermediate product is obtained.

[0087] The post-processing method includes the following: cooling to below 25℃, adding 5% CaCl2 solution and stirring for 15 min, centrifuging for 12 min to obtain the middle layer resin flocculent; washing the resin flocculent three times with a mixed solvent of 16 L acetone and 8 L water at 60℃, and vacuum drying at 60~62℃ for 23.5 h; the mass of the added 5% CaCl2 accounts for 5.1% of the total mass of the emulsion after the reaction in step 3.

[0088] Step 4: Take 500g of the intermediate product obtained in Step 3, 160g of 2-bromoisobutyryl bromide, and 275g of triethylamine and add them to 6704mL of a mixed solvent of THF and water. React at 62℃ under N2 protection for 2.2h. Cool down to 52℃, add PFBMA, CuBr, and PMDETA, and react under N2 protection for 12.5h. Stop the reaction by purging with air and add a perfluoropolyether surfactant.

[0089] The resin intermediate was prepared with THF at a solid content of 10.5%, and the volume ratio of THF to water was 2.5:1.

[0090] Step 5: Add the pre-dispersed KH-570 modified nano-SiO2 to the solution obtained in Step 4 and stir until homogeneous; heat to 76℃, add bisphenol A epoxy resin E-51, and stir for 1.1 h; cool to 40℃, adjust pH to 8.0 with ammonia water, filter through a 190-mesh filter to obtain modified acrylic resin.

[0091] The pre-dispersion method of KH-570 modified nano-SiO2 includes: controlling the temperature in an ice-water bath at 28℃, ultrasonically dispersing 40g of KH-570 modified nano-SiO2 in 480g of propylene glycol methyl ether for 30 min, with an ultrasonic dispersion power of 400 W.

[0092] Comparative Example 1

[0093] The traditional preparation process for modified acrylic resins includes the following raw materials:

[0094] MMA: 400g, BA: 300g, HEA: 120g; PFBMA: 230g; KH-560: 65g; SDS: 12g; Emulsifier OP-10: 10g; APS: 10g; Nano SiO2 (unmodified): 30g.

[0095] The preparation process of modified acrylic resin includes the following steps:

[0096] Step 1: Preparation of pre-emulsion: Mix all monomers MMA, BA, HEA, PFBMA, and KH-560; add SDS, OP-10, and deionized water (60% of total volume), and stir at 25°C for 30 min to obtain the pre-emulsion.

[0097] Step 2: Emulsion polymerization: Add the remaining deionized water (40%) and 0.2 parts of NaHCO3 to the reactor, and heat to 85℃;

[0098] Add 50% of the total APS and stir for 10 min; add the entire pre-emulsion at once, dropping at a rate of 4 mL / min (rapid addition).

[0099] The reaction was carried out at 85℃ for 3 hours.

[0100] Step 3: Addition of nanofiller: Cool to 70℃ and add unmodified nano-SiO2; stir for 1 h (non-ultrasonic dispersion).

[0101] Step 4: Demulsification and post-treatment: Add 8% Al2(SO4)3 solution (dosage: total emulsion mass × 0.08); centrifuge, wash the resin flocculent with acetone:water = 1:1 (volume ratio); dry with hot air at 80℃ for 24 h to obtain solid resin.

[0102] The performance comparison data of Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0103] Table 1 Performance comparison data of Examples 1-3 and Comparative Example 1

[0104] Performance indicators Example 1 Example 2 Example 3 Comparative Example 1 Fluorine grafting rate (%) 93.5% 92.8% 94.1% 78.2% Epoxy retention rate (%) 89.7% 90.2% 88.5% 61.3% OTR (cc / m²·day) 3.9 4.1 3.8 15.2 Water contact angle 117° 115° 118° 102° Adhesion (cross-cut test) 5B 5B 5B 3B gelation rate (%) 0.2% 0.3% 0.1% 6.5% VOC emissions (g / L) 20 27 26 105 Wastewater COD (mg / L) 680 780 750 5000 Particle size uniformity (PDI) 0.08 0.12 0.10 0.43

[0105] As shown in Table 1, the fluoride grafting rate in Examples 1-3 was >92%, an increase of 16% compared to 78.2% in Comparative Example 1; the epoxy retention rate was >88.5%, an increase of 29% compared to 61.3% in Comparative Example 1; the oxygen permeability (OTR) was controlled at ≤4.1cc / m²·day, a decrease of 75% compared to 15.2cc / m²·day in Comparative Example 1; and the water contact angle was >115°, an increase of 16° compared to 102° in Comparative Example 1. The adhesion was 5B, an improvement of 2 levels compared to 3B in Comparative Example 1; the gelation rate was less than 0.3%, a reduction of 95% compared to Comparative Example 1; VOC emissions could be controlled below 27g / L, a decrease of 75% compared to 105g / L in Comparative Example 1; the wastewater COD could be controlled at 780mg / L, a reduction of 85% in treatment cost compared to 5000mg / L in Comparative Example 1; and the particle size uniformity was less than 0.13, compared to 0.43 in Comparative Example 1.

[0106] In summary, the present invention utilizes an ATRP system of HEA positioning, epoxy / fluorine stepwise grafting, and water / THF synergy to prepare modified acrylic resin, which has significant advantages over traditional preparation processes. Among them, Example 1 is the optimal example.

[0107] Example 4

[0108] A water-based ink with barrier properties, comprising the following components:

[0109] Modified acrylic resin (prepared in Example 1): 400g; Composite titanium red 57DT4659: 150g; Montmorillonite: 100g; Polyester dispersant 1998: 20g; Acrylylene diol wetting agent Dynol 960: 10g; Organosilicon composite defoamer SXP-107-1: 3g; Low viscosity modified siloxane leveling agent BYK-347: 3g; Trimethylolpropane tris(2-methylaziridine)propionate: 35g; Deionized water 279g;

[0110] The modified acrylic resin has perfluorobutyl, glycidyl etheroxy and hydroxyl groups grafted onto its molecular chain, and the montmorillonite has a particle size of 450 nm and an aspect ratio of 52.

[0111] A preparation process applicable to the aforementioned water-based ink with barrier properties includes the following steps:

[0112] S100. Add the filler, 5g wetting agent, and 6g dispersant to 40% of the total amount of deionized water. Sonicate at 60℃ for 30min with an ultrasonic power of 40kHz to fully exfoliate the filler and form a pre-activated slurry with a fineness of 3μm. In a separate container, mix the pigment, defoamer, and remaining dispersant with 55.8g of deionized water and pre-disperse by high-speed shearing at 5000rpm for 15min to obtain a concentrated pigment slurry.

[0113] S200. Add the modified acrylic resin to the pre-activated slurry of step S100, heat to 75°C at a rate of 3°C / min, slowly add 17.5g of crosslinking agent, and react for 1 hour.

[0114] Cool the reaction system to 40°C at a rate of 4°C / min, add 83.7g of deionized water, then add the pigment concentrate, leveling agent and remaining wetting agent from step S100, stir evenly, add the remaining deionized water, stir at low speed for 20min at 250rpm, mix evenly to obtain a mixed slurry.

[0115] S300: Grind the mixture from step S200 to a fineness of 3μm at 30℃; immediately after grinding, add the remaining crosslinking agent, then add ammonia water, adjust the pH to 8.5, stir at low speed (200 rpm), and after 10 minutes, filter through a 4-micron pore size filter membrane to obtain the target product.

[0116] Example 5

[0117] A water-based ink with barrier properties, comprising the following components:

[0118] Modified acrylic resin (prepared in Example 1): 500g; Resinized phthalocyanine blue B2G 131-CN: 100g; Montmorillonite: 50g; Polyester dispersant 1998: 10g; Acrylylene diol wetting agent Dynol 960: 5g; Organosilicon composite defoamer SXP-107-1: 1g; Low viscosity modified siloxane leveling agent BYK-347: 1g; Trimethylolpropane tris(2-methylaziridine)propionate: 20g; 313g deionized water;

[0119] The modified acrylic resin has perfluorobutyl, glycidyl etheroxy and hydroxyl groups grafted onto its molecular chain, and the montmorillonite has a particle size of 400 nm and an aspect ratio of 58.

[0120] A preparation process applicable to the aforementioned water-based ink with barrier properties includes the following steps:

[0121] S100. Add the filler, 2.25g wetting agent, and 2.5g dispersant to 109.6g of deionized water. Sonicate at 55℃ for 28min with an ultrasonic power of 40kHz to fully exfoliate the filler and form a pre-activated slurry with a fineness of 4μm. In a separate container, mix the pigment, defoamer, and remaining dispersant with 47g of deionized water and pre-disperse by high-speed shearing at 4500rpm for 12min to obtain a concentrated pigment slurry.

[0122] S200. Add the modified acrylic resin to the pre-activated slurry of step S100, heat to 72°C at a rate of 5°C / min, slowly add 9g of crosslinking agent, and react for 0.8h.

[0123] Cool the reaction system to 38°C at a rate of 3°C / min, add 62.6g of deionized water, then add the pigment concentrate, leveling agent and remaining wetting agent from step S100, stir evenly, add the remaining deionized water, stir at low speed for 18min at 200rpm, mix evenly to obtain a mixed slurry.

[0124] S300: Grind the mixture from step S200 to a fineness of 4μm at 35℃. Immediately after grinding, add the remaining crosslinking agent, then add ammonia water, adjust the pH to 8.2, stir at low speed (280 rpm), and after 8 minutes, filter through a 3-micron pore size filter membrane to obtain the target product.

[0125] Example 6

[0126] A water-based ink with barrier properties, comprising the following components:

[0127] Modified acrylic resin (prepared in Example 1): 300g; Composite titanium red 57DT4659: 200g; Montmorillonite: 50g; Polyester dispersant 1998: 30g; Acrylylene diol wetting agent Dynol 960: 20g; Organosilicon composite defoamer SXP-107-1: 5g; Low viscosity modified siloxane leveling agent BYK-347: 5g; Trimethylolpropane tris(2-methylaziridine)propionate: 50g; 340g deionized water;

[0128] The modified acrylic resin has perfluorobutyl, glycidyl etheroxy and hydroxyl groups grafted onto its molecular chain, and the montmorillonite has a particle size of 460 nm and an aspect ratio of 55.

[0129] A preparation process applicable to the aforementioned water-based ink with barrier properties includes the following steps:

[0130] S100. Add the filler, 11g wetting agent, and 10.5g dispersant to 153g deionized water. Sonicate at 65℃ for 32min with an ultrasonic power of 40kHz to fully exfoliate the filler and form a pre-activated slurry with a fineness of 2μm. In a separate container, mix the pigment, defoamer, and remaining dispersant with 85g deionized water and pre-disperse by high-speed shear at 5500rpm for 18min to obtain a concentrated pigment slurry.

[0131] S200: Add the modified acrylic resin to the pre-activated slurry from step S100, heat to 78°C at a rate of 5°C / min, slowly add 27.5g of crosslinking agent, and react for 1.2h.

[0132] Cool the reaction system to 42°C at a rate of 4°C / min, add 119g of deionized water, then add the pigment concentrate, leveling agent and remaining wetting agent from step S100, stir evenly, add the remaining deionized water, stir at low speed for 22min at 300rpm, mix evenly to obtain a mixed slurry.

[0133] S300: Grind the mixture from step S200 to a fineness of 3μm at 30°C. Immediately after grinding, add the remaining crosslinking agent, then add ammonia water, adjust the pH to 8.6, stir at low speed (300 rpm), and after 12 minutes, filter through a 5-micron pore size membrane to obtain the target product.

[0134] Comparative Example 2

[0135] A water-based ink with barrier properties, comprising the following components:

[0136] Acrylic resin: 400g; Titanium red: 150g; Montmorillonite: 100g; Polyester dispersant 1998: 20g; Acrylylene diol wetting agent Dynol 960: 10g; Organosilicon composite defoamer SXP-107-1: 3g; Low viscosity modified siloxane leveling agent BYK-347: 3g; Isocyanate crosslinking agent: 35g; 279g deionized water; Montmorillonite particle size 450nm, aspect ratio 28.

[0137] A preparation process applicable to the aforementioned water-based ink with barrier properties includes the following steps:

[0138] S100. Add montmorillonite, wetting agent, pigment, defoamer, and dispersant to 167.4g of deionized water, and mechanically stir at 25℃ for 15min at 3000rpm to form a pre-activated slurry with a fineness of 8.5μm.

[0139] S200. Add acrylic resin to the pre-activated slurry from step S100, heat to 75°C, slowly add crosslinking agent, and react for 1 hour; cool the reaction system to 40°C, add 83.7g of deionized water, then add leveling agent, stir evenly, add the remaining deionized water, stir at low speed for 20 minutes at 250 rpm, mix evenly, and obtain a mixed slurry.

[0140] S300: Grind the mixture from step S200 to a fineness of 6.8 μm at 45°C; then add ammonia water, adjust the pH to 8.5, stir at low speed (200 rpm) for 10 minutes, and filter through a 4-micron pore size membrane to obtain the target product.

[0141] The performance comparison data of Examples 4-6 and Comparative Example 2 are shown in Table 2.

[0142] Table 2 Performance comparison data of Examples 4-6 and Comparative Example 2

[0143] Performance indicators Example 4 Example 5 Example 6 Comparative Example 2 <![CDATA[OTR (cc / m 2 ·day)]]> 4.1 4.2 3.9 15.6 WVTR (g / m²·day) 2.3 2.5 2.0 9.8 Drying rate (m / min) 150 145 155 80 VOC emissions (g / L) 28 30 26 105 Storage stability at 50℃ Viscosity increased by 9% Viscosity increased by 11% Viscosity increased by 8% Turn into a gel

[0144] As shown in Table 2, the oxygen permeability (OTR) of the inks in Examples 4-6 is ≤4.2cc / m. 2• day, significantly lower than 15.6 cc / m 2 •day; Water vapor transmission rate (WVTR) was ≤2.5 g / m²·day, significantly lower than 9.8 g / m²·day of Comparative Example 2; Drying speed reached 155 m / min, significantly higher than 80 m / min of Comparative Example 2; VOC emissions were all below 30 g / L, a 62% reduction compared to Comparative Example 2; Viscosity increased by only 11% during storage at 50℃, and no gel was formed, which was significantly better than Comparative Example 2.

[0145] In Comparative Example 2, the montmorillonite's aspect ratio was less than 30, resulting in numerous pores in the layered stack, leading to a significant increase in the ink's OTR. The crosslinking agent was added only once, causing uncontrolled reaction at high temperatures, resulting in localized gelation and a doubling of viscosity after 7 days of storage. Mixing titanium red with montmorillonite caused wear and loss of moisture barrier properties. The process chain of this invention—segmented peeling, pre-crosslinking protection, and directional final curing—solves the triangular contradiction of dispersion, crosslinking, and arrangement in high-barrier water-based inks, achieving an industry breakthrough of OTR < 4.5 cc / m²·day and VOC < 30 g / L, far exceeding the performance of Comparative Example 2.

Claims

1. An aqueous ink having barrier properties, characterized in that, By weight percentage, including the following components: Modified acrylic resin: 30~50%; pigment: 10~20%; montmorillonite: 5~15%; polyester dispersant: 1~3%; acetylenic diol wetting agent: 0.5~2%; silicone composite defoamer: 0.1~0.5%; low viscosity modified siloxane leveling agent: 0.1~0.5%; aziridine crosslinking agent: 2~5%; the balance is deionized water; Wherein, the molecular chain of the modified acrylic resin is grafted with perfluorobutyl, glycidyl ether oxy and hydroxyl, the particle size of the montmorillonite is less than 500 nm, and the diameter-thickness ratio is > 50; The preparation process of the modified acrylic resin, including the following raw materials by weight parts: MMA: 35~45 parts, BA: 25~35 parts, HEA: 10~15 parts; SDS: 1.0~1.5 parts, emulsifier OP-10: 0.8~1.2 parts; APS: 0.8~1.2 parts; hydroquinone: 0.01~0.02 parts; sodium bicarbonate: 0.1~0.3 parts; deionized water: 120~150 parts; KH-560: 6~8 parts; titanium isopropylate: 0.1~0.3 parts; PFBMA: 20~25 parts; CuBr: 4~5 parts; PMDETA: 10~12 parts; perfluoropolyether surfactant: 7~8 parts; KH-570 modified nano-SiO2: 2–4 parts; E-51: 3~5 parts; The preparation process of the modified acrylic resin, including the following steps: Step 1, dissolve SDS and buffer NaHCO3 accounting for 28~32% of the total amount in deionized water accounting for 20~25% of the total amount, heat to 78~82℃, replace with nitrogen for 14~16min; add initiator APS accounting for 29~31% of the total amount, low-speed stirring; add pre-emulsion accounting for 9~11% of the total amount at a rate of 1ml / min, keep temperature at 79~81℃, react for 28~32min; Step 2, dissolve the remaining initiator APS in the remaining deionized water to make a solution, add the remaining pre-emulsion and initiator APS solution to the solution obtained in step 2 at a rate of 2 mL / min, control the temperature at 78~82℃; 28~32min before the remaining pre-emulsion is added, reduce the temperature to 74~76℃, add HEA, mix quickly for 8~12 min; Step 3, reduce the temperature to 60℃, add KH-560 in 3 batches, each batch interval is 18~22 min, add sodium bicarbonate, adjust pH to 6.5~7.5, then add 5% ethanol solution of titanium isopropylate, keep temperature and react for 2.8~3.2h; after treatment, dry resin intermediate product is obtained; Step 4, add the intermediate product obtained in step 3, 2-bromoisobutyryl bromide and triethylamine to the mixed solvent of THF and water, protect under N2 at 58~62℃, react for 1.8~2.2h; reduce the temperature to 48~52℃, add PFBMA, CuBr and PMDETA, protect under N2, react for 11.5~12.5h; terminate the reaction by passing air, add perfluoropolyether surfactant; Step 5, the pre-dispersed KH-570 modified nano-SiO2 is added into the solution obtained in step 4 and stirred uniformly; the temperature is raised to 74-76 DEG C, bisphenol A epoxy resin E-51 is added, and stirring is carried out for 0.9-1.1 h; the temperature is cooled to 35-40 DEG C, ammonia is added to adjust the pH to 7.5-8.0, and the product is filtered through a 180-200 mesh filter screen to obtain the modified acrylic resin.

2. The water-based ink with barrier properties according to claim 1, characterized in that, The pigment is selected from one of the complex titanium red or resinized phthalo blue; the aziridine crosslinking agent is trimethylolpropane tris(2-methylaziridine) propionate.

3. A process for the preparation of an aqueous ink with barrier properties, suitable for use in a device as claimed in any one of the claims 1-2, characterized in that, The method comprises the following steps: S100, the filler is added into deionized water accounting for 35-45% of the total amount, 45-55% of the total amount of wetting agent, and 25-35% of the total amount of dispersant, and the filler is fully peeled at 55-65 DEG C under ultrasonic treatment for 28-32 min to form a pre-activated slurry with a fineness of less than 5 microns; another container is prepared, and the pigment, defoaming agent and the remaining dispersant are mixed with 15-25% of the total amount of deionized water, and pre-dispersed by high-speed shearing to obtain a pigment concentrate slurry; S200, the modified acrylic resin is added to the pre-activated slurry of step S100, the temperature is raised to 72-78 DEG C, 45-55% of the crosslinking agent is slowly added, and the reaction is carried out for 0.8-1.2 h; The reaction system is cooled to 38-42 DEG C at a cooling rate of ≤5 DEG C / min, 20-35% of the total amount of deionized water is added, and the pigment concentrate slurry of step S100, leveling agent and the remaining wetting agent are added, stirred uniformly, and the remaining deionized water is added, low-speed stirring for 18-22 min, and mixed uniformly to obtain a mixed slurry; S300, the mixed slurry of step S200 is ground to a fineness of less than 5 microns at a temperature of ≤35 DEG C; Immediately after grinding, the remaining crosslinking agent is added, ammonia is added, the pH is adjusted to 8.2-8.6, and low-speed stirring is carried out for 8-12 min to obtain the target product.

4. The manufacturing process of claim 3, wherein, In step S100, the power of ultrasonic wave is 40 kHz, the speed of high-speed shearing is 4500-5500 rpm, and the time is 12-18 min; in step S200, the temperature rising rate is ≤5 DEG C / min; the speed of low-speed stirring is 200-300 rpm.

5. The water-based ink with barrier properties according to claim 1, characterized in that, In step 1, the preparation process of the pre-emulsion includes the following contents: after premixing MMA, BA and 65-75% of the total amount of HEA, adding 68-72% of the total amount of SDS, emulsifier OP-10 and hydroquinone into 55-65% of the total amount of deionized water, low-speed stirring for 30 min at 15-25 DEG C to obtain the pre-emulsion; in step 2, the mass of additional HEA is 25-35% of the total mass of HEA.

6. The water-based ink with barrier properties according to claim 1, characterized in that, In step 3, the post-treatment method comprises the following contents: cooling to below 25℃, adding 5% CaCl2 solution and stirring for 15 min, centrifugal separation for 8~12 min, and obtaining the middle layer resin flocculation; at 60℃, the resin flocculation is washed with acetone-water mixed solvent for 2~3 times, vacuum drying at 60~62℃ for 23~24 h; the volume ratio of acetone to water is 1~2:1; the mass of the added 5% CaCl2 accounts for 4.9~5.1% of the total mass of the emulsion after the completion of step 3 reaction.

7. The water-based ink with barrier properties according to claim 1, characterized in that, In step 4, the mass ratio of the intermediate product, 2-bromoisobutyryl bromide and triethylamine is 1:0.28~0.32:0.50~0.55; the resin intermediate product is prepared with THF according to the solid content of 9~11%, and the volume ratio of THF to water is 2.2~2.5:

1.

8. The water-based ink with barrier properties according to claim 1, characterized in that, The pre-dispersion method of the KH-570 modified nano-SiO2 comprises: controlling the ice water bath temperature to be ≤30℃, ultrasonic dispersing the KH-570 modified nano-SiO2 in propylene glycol methyl ether for 20~30 min, the ultrasonic dispersion power is 300~400 W, and the mass ratio of the KH-570 modified nano-SiO2 to propylene glycol methyl ether is 1:8~12.