Formula and preparation method of heat-adhesion-resistant water-based plastic gravure ink

Abstract

The invention discloses a formula of heat-adhesion-resistant water-based plastic gravure ink and a preparation method thereof, and belongs to the technical field of printing materials, the formula comprises a water-based acrylic resin emulsion, a water-based polyurethane dispersion, a coloring pigment, a composite anti-adhesion auxiliary agent, a wetting dispersant, a defoaming agent, a leveling agent, a pH regulator and deionized water; the composite anti-adhesion auxiliary agent is composed of an organosilicon modified wax emulsion, hollow glass microspheres and cross-linked polyurethane particles. The invention also provides a preparation method of the composite anti-adhesion auxiliary agent. By designing a ternary composite anti-adhesion aid synergistic system and an optimized formula process, 24-hour non-adhesion is kept at the high temperature of 60 DEG C and the pressure of 0.2 MPa, the high-temperature and high-humidity environment requirements of summer storage and long-distance transportation in tropical and subtropical regions are met, and meanwhile, the high-adhesion and high-glossiness flexible hot melt adhesive also has high adhesion, high glossiness, good flexibility and storage stability.

Description

Technical Field

[0001] This invention relates to the field of printing materials, and in particular to a formulation and preparation method of a heat-resistant, water-based plastic gravure ink. Background Technology

[0002] Gravure printing on plastics is widely used in food packaging, daily chemical packaging, and other fields. The performance of the inks directly affects the practicality and safety of the printed materials. Traditional gravure inks for plastics are mostly solvent-based. However, with increasingly stringent global environmental regulations, solvent-based gravure inks are gradually being replaced by water-based inks due to their high VOC emissions and potential safety hazards. However, water-based inks face a core technological bottleneck in plastic film printing—thermal adhesion. Adhesion can lead to scratches on the images and text, and the inability to unwind the roll, resulting in a scrap rate as high as 15%-20%, severely restricting the application of water-based inks in high-end fields such as food packaging and daily chemical packaging.

[0003] Existing technologies mostly use single organosilicone wax emulsions or inorganic microparticles as anti-blocking agents. However, while single organosilicone wax emulsions can improve surface smoothness, they have poor temperature resistance (thermal adhesion temperature ≤45℃) and are prone to migration and loss during long-term storage. If the particle size of inorganic microparticles is not properly controlled, it can easily lead to roughness and reduced gloss of printed materials. If the particle size is too small, it cannot form an effective physical gap, resulting in a weak anti-blocking effect.

[0004] Based on the above problems, a formulation and preparation method for a water-based plastic gravure ink with heat-resistant adhesion are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a formulation and preparation method of a heat-resistant, water-based plastic gravure ink to solve the problems in the background art.

[0006] To achieve the above objectives, the present invention provides a formulation for a heat-resistant, adhesive-resistant water-based plastic gravure ink, comprising the following components by weight: The composition includes 30-50 parts of waterborne acrylic resin emulsion, 10-20 parts of waterborne polyurethane dispersion, 15-25 parts of coloring pigment, 3-8 parts of composite anti-blocking agent, 0.5-1.5 parts of wetting and dispersing agent, 0.1-0.5 parts of defoamer, 0.2-0.8 parts of leveling agent, 0.5-1.5 parts of pH adjuster, and 10-20 parts of deionized water. The composite anti-adhesion additive is composed of organosilicon-modified wax emulsion, hollow glass microspheres, and cross-linked polyurethane microparticles.

[0007] Preferably, in the composite anti-adhesion additive, the weight ratio of organosilicon modified wax emulsion, hollow glass microspheres, and cross-linked polyurethane microparticles is (2~3):(1~2):1.

[0008] Preferably, the organosilicon-modified wax emulsion has a solid content of 30-40%, a particle size ≤100nm, and a silicon content of 5-8%. The hollow glass microspheres have an average particle size of 5~20μm, a wall thickness of 0.5~1.5μm, a true density of 0.15~0.30g / cm³, and a compressive strength ≥0.5MPa; The cross-linked polyurethane microparticles have an average particle size of 0.1~0.5μm, contain 2~3% isocyanate groups, and have a glass transition temperature of 50~60℃.

[0009] Preferably, the weight ratio of the aqueous acrylic resin emulsion to the aqueous polyurethane dispersion is (2.5~3.5):1.

[0010] Preferably, the waterborne acrylic resin emulsion has a glass transition temperature (Tg) of 30~40℃, a solid content of 40~50%, a weight-average molecular weight (Mw) of 50000~80000 g / mol, and an acid value of 50~70 mgKOH / g; the waterborne polyurethane dispersion has a solid content of 35~45%, an elongation of ≥300%, and a minimum film-forming temperature (MFFT) of ≤10℃.

[0011] Preferably, the coloring pigment is one of Phthalocyanine Blue BGS with an average particle size of 0.1~0.5μm, Carbon Black FW200 with an average particle size of 13nm, and Permanent Yellow G with an average particle size of 0.2~0.6μm.

[0012] Preferably, the wetting and dispersing agent is a polycarboxylate polymeric dispersant; the defoamer is an organosilicon defoamer; the leveling agent is a polyether-modified siloxane leveling agent; and the pH adjuster is ammonia or dimethylethanolamine at a concentration of 28-30%.

[0013] This invention also provides a method for preparing the above-mentioned anti-heat-blocking water-based plastic gravure ink formulation, comprising the following steps: S1. Premixing stage: Add deionized water to the high-speed disperser, and add wetting and dispersing agent, 50% defoamer and pH adjuster in sequence under stirring. Stir until the solution is clear and transparent. S2, Pigment Dispersion Stage: Add coloring pigment while maintaining stirring, increase the rotation speed for high-speed dispersion, and use a scraper fineness gauge to check the fineness of the slurry multiple times during the process until the fineness of the slurry is ≤15μm, so as to obtain a uniform and stable color paste. S3. Paint mixing stage: Reduce the rotation speed and slowly add water-based acrylic resin emulsion, water-based polyurethane dispersion, leveling agent, and the remaining 50% defoamer to the color paste in sequence. Stir until the system is uniform and there are no visible layers or eddy streaks. S4. Core Additive Addition Stage: Maintain a rotation speed of 300~500 rpm, slowly add the composite anti-blocking additive, and continue stirring for 20~30 minutes to ensure that the additive is evenly dispersed and not damaged. S5. Filtration and Curing Stage: Use a 200-300 mesh nylon filter to remove any coarse particles or broken microspheres. Then place it in a sealed container for static curing to obtain heat-resistant, non-sticking water-based plastic gravure ink. In addition, after curing, the ink's viscosity, pH value, and other key indicators need to be tested. Only after passing the tests can the ink be used.

[0014] Preferably, in step S1, the stirring speed is 300~400 rpm and the stirring time is 5~10 min.

[0015] Preferably, in step S2, the stirring speed is 1000~1500 rpm and the stirring time is 30~45 min.

[0016] Preferably, in step S3, the stirring speed is 400~600 rpm and the stirring time is 15~20 min.

[0017] Preferably, in step S4, cross-linked polyurethane microparticles and hollow glass microspheres are added sequentially to the silicone-modified wax emulsion under low-speed stirring conditions of 200-400 rpm, the temperature is controlled at 25-40℃, and stirring is continued for 30-60 minutes until the mixture is uniform, resulting in a homogeneous composite anti-blocking agent dispersion. This method utilizes the lubricating and encapsulating effect of the wax emulsion to make the latter two easier to disperse, which helps to achieve a uniform state more quickly in the subsequent ink preparation.

[0018] Preferably, in step S5, the curing temperature is 25~27℃, the relative humidity is 40~60%, and the resting time is 20~30h.

[0019] The composite anti-adhesion additive used in this invention consists of a silicone-modified wax emulsion, hollow glass microspheres, and cross-linked polyurethane microparticles. These three components form a three-dimensional protective system of "surface lubrication - physical support - bulk reinforcement." The core function of the silicone-modified wax emulsion is to construct a "low surface energy lubrication layer" on the ink film surface, reducing adhesion tendency from the source, thus serving as the "first line of defense" against adhesion. The core function of the hollow glass microspheres is to construct "microscopic support pillars" inside the ink film, preventing large-area tight adhesion between the ink film and the contact surface through physical spacing, thus serving as the "second line of defense" against adhesion. The core function of the cross-linked polyurethane microparticles is to enhance the bulk hardness and heat resistance of the ink film through cross-linking reactions, preventing adhesion caused by softening and deformation of the ink film at high temperatures, thus serving as the "third line of defense" against adhesion. This creates a synergistic effect of "1+1+1>3," specifically: Although the surface wax layer of silicone-modified wax emulsion is stable at 60°C, if the ink film softens, the wax layer will break down as the ink film deforms, losing its lubricating effect. However, the cross-linking enhancement of cross-linked polyurethane microparticles can ensure that the ink film does not deform at high temperatures, providing "structural support" for the wax layer of silicone-modified wax emulsion and ensuring the continuous effectiveness of the lubricating layer. The microscopic support of hollow glass microspheres requires the ink film to have sufficient strength to fix the position of the microspheres; the cross-linked network of cross-linked polyurethane microparticles can "anchor" the microspheres within the ink film, preventing the microspheres from sliding under pressure and ensuring the continuity of the support effect. The dispersion of hollow glass microspheres depends on the encapsulation of silicone-modified wax emulsion; the wax layer of silicone-modified wax emulsion can reduce the interfacial tension between the hollow glass microspheres and the resin, allowing the hollow glass microspheres to be uniformly dispersed and ensuring the continuity of the support network.

[0020] Therefore, the formulation and preparation method of the heat-resistant water-based plastic gravure ink of the present invention have the following beneficial effects: (1) Through the ternary synergistic system of "organosilicon wax (surface lubrication) - hollow microspheres (physical support) - cross-linked microparticles (bulk reinforcement)," it is possible to maintain non-adhesion for 24 hours under high temperature of 60℃ and pressure of 0.2MPa, which is far beyond the level of existing technologies that can usually only cope with 40℃ environment. It can meet the high temperature and high humidity environment requirements of summer storage and long-distance transportation in tropical and subtropical regions, and solve the core bottleneck of water-based plastic gravure ink application.

[0021] (2) After the anti-adhesion is improved, the other properties of this invention can also maintain excellent performance. Its adhesion reaches level 0, ensuring that the printed pattern is firmly attached and does not fall off in various post-processing (such as lamination and bag making). The gloss is ≥85%, which is much higher than that of inks with added traditional anti-adhesion agents, meeting the requirements of high-end packaging for appearance quality. Its flexibility allows for 180° bending without cracking, ensuring that the plastic soft packaging will not be damaged by bending during use and transportation. After 7 days of storage, there is no hard sedimentation and the sedimentation rate is <5%, solving the problem of easy sedimentation of traditional inorganic anti-adhesion agents.

[0022] (3) It uses water as the dispersion medium and the VOC content is far below the limit of the national mandatory standard GB38507-2020 (≤50g / L), which is in line with the green and environmentally friendly development trend. The preparation method does not require special or expensive equipment and can be achieved by controlling the speed in the existing high-speed disperser, which is easy to scale up production.

[0023] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0024] The technical solution of the present invention will be further described below through embodiments.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0026] The main raw materials used in the following examples and comparative examples are: Aqueous acrylic resin emulsion, Tg=35℃, solid content 45%.

[0027] Waterborne polyurethane dispersion, solid content 40%, elongation 350%.

[0028] The composite anti-adhesion additive is: Organosilicon-modified wax emulsion, solid content 35%, particle size 80nm; Hollow glass microspheres, with an average particle size of 10 μm and a true density of 0.25 g / cm³. 3 ; Cross-linked polyurethane microparticles, with a particle size of 0.3 μm and an -NCO content of 2.5%; A uniform dispersion of the composite anti-blocking agent was obtained by pre-mixing.

[0029] Pigments: Phthalocyanine Blue BGS, Carbon Black FW200.

[0030] Wetting and dispersing agent, defoamer, leveling agent, 28% ammonia water; deionized water (conductivity ≤10μS / cm).

[0031] Example 1 This embodiment prepares a blue, heat-resistant, water-based plastic gravure ink. The specific raw materials, by weight, are as follows: The mixture contains 40 parts of waterborne acrylic resin emulsion and 15 parts of waterborne polyurethane dispersion, with a resin ratio of waterborne acrylic resin emulsion: waterborne polyurethane dispersion = 2.67:1.

[0032] Five parts of the composite anti-adhesion additive are specifically: organosilicon modified wax emulsion: hollow glass microspheres: cross-linked polyurethane microparticles = 2:1:1.

[0033] 20 parts phthalocyanine blue, 1 part wetting and dispersing agent, 0.3 parts defoamer, 0.5 parts leveling agent, 1 part 28% ammonia water, and 15.7 parts deionized water.

[0034] The specific preparation steps are as follows: S1. Premixing stage: Add deionized water to the high-speed disperser, and add wetting and dispersing agent, 50% defoamer and 28% ammonia water in sequence under stirring at 350 rpm. Stir for 8 minutes until the solution is clear and transparent. S2, Pigment Dispersion Stage: Add coloring pigment while maintaining stirring, increase the rotation speed to 1200 rpm for high-speed dispersion for 40 minutes. During this period, the fineness of the slurry can be checked multiple times with a scraper fineness gauge until the fineness of the slurry is ≤15μm, so as to obtain a uniform and stable color paste. S3. Paint mixing stage: Reduce the speed to 500 rpm, and slowly add water-based acrylic resin emulsion, water-based polyurethane dispersion, leveling agent and the remaining 50% defoamer to the color paste in sequence. Stir for 18 minutes until the system is uniform and there are no visible layers or eddy streaks. S4. Core Additive Addition Stage: Maintain a rotation speed of 400 rpm, slowly add the composite anti-blocking additive, and continue stirring for 25 minutes to ensure that the additive is evenly dispersed and not damaged. S5. Filtration and maturation stage: Use a 250-mesh nylon filter to remove any coarse particles or broken microspheres that may be present. Then place it in a sealed container and mature at 25°C and 50% relative humidity for 24 hours.

[0035] Example 2 This embodiment prepares a blue, heat-resistant, water-based plastic gravure ink. The specific raw materials, by weight, are as follows: The mixture consists of 35 parts of waterborne acrylic resin emulsion and 10 parts of waterborne polyurethane dispersion, with a resin ratio of waterborne acrylic resin emulsion: waterborne polyurethane dispersion = 3.5:1.

[0036] Four parts of the composite anti-blocking agent are specifically: organosilicon modified wax emulsion: hollow glass microspheres: cross-linked polyurethane microparticles = 2.5: 1.5: 1.

[0037] Phthalocyanine blue 18 parts, wetting and dispersing agent 0.8 parts, defoamer 0.2 parts, leveling agent 0.4 parts, 28% ammonia water 1.8 parts, deionized water 17.2 parts.

[0038] The specific preparation steps are the same as in Example 1, except that the rotation speed in step S4 is changed to 300 rpm.

[0039] Example 3 This embodiment prepares a black, heat-resistant, water-based plastic gravure ink. The specific raw materials, by weight, are as follows: The mixture consists of 45 parts of waterborne acrylic resin emulsion and 15 parts of waterborne polyurethane dispersion, with a resin ratio of waterborne acrylic resin emulsion to waterborne polyurethane dispersion of 3:1.

[0040] Six parts of composite anti-blocking additive, specifically: organosilicon modified wax emulsion: hollow glass microspheres: cross-linked polyurethane microparticles = 3:2:1.

[0041] 22 parts carbon black, 1.2 parts wetting and dispersing agent, 0.4 parts defoamer, 0.6 parts leveling agent, 1.2 parts 28% ammonia water, and 12.2 parts deionized water.

[0042] The specific preparation steps are the same as in Example 1, except that the rotation speed in step S4 is changed to 500 rpm.

[0043] The performance of the heat-resistant water-based plastic gravure inks prepared in Examples 1-3 was tested, and the specific results are shown in Table 1. Table 1 Performance Test Results

[0044] Comparative Example 1 The preparation steps in Comparative Example 1 are the same as in Example 1, except that the raw materials are modified so that no composite anti-adhesion agent is added and 5 parts of para-ionized water are added.

[0045] Testing revealed that the product exhibited "severe adhesion" in its heat resistance, making it impossible to peel off the roll material normally. Other properties included adhesion grade 1 and gloss level of 88%, which were acceptable, but the core function was completely lost, demonstrating the necessity of composite anti-adhesion additives.

[0046] Comparative Example 2 The preparation steps for this comparative example are the same as those for Example 1, except that the composite anti-blocking agent in the raw materials is changed to a single organosilicon-modified wax emulsion, with a dosage of 5 parts.

[0047] Testing revealed that the product's heat resistance to adhesion was "adhesive," and the graphics showed obvious scratches. This indicates that the product only has surface lubrication, lacks physical support and bulk reinforcement, and cannot withstand high temperatures and pressures.

[0048] Comparative Example 3 The preparation steps of this comparative example are the same as those of Example 1, except that the composite anti-blocking agent in the raw materials is changed to organosilicon modified wax emulsion + hollow glass microspheres, with a total amount of 5 parts and a ratio of 2.5:1.5.

[0049] Testing revealed that the product exhibited "slight adhesion" in terms of its resistance to thermal adhesion. This performance was superior to Comparative Example 2, indicating the effectiveness of the "surface lubrication + physical support" approach. However, because the ink film itself still softens at high temperatures, adhesion could not be completely avoided, demonstrating the indispensable role of the cross-linking enhancement in the waterborne polyurethane dispersion.

[0050] Comparative Example 4 The preparation steps of this comparative example are the same as those of Example 1, except that the amount of waterborne acrylic resin emulsion is modified to 30 parts and the amount of waterborne polyurethane dispersion is modified to 20 parts, with a ratio of 1.5:1.

[0051] Testing revealed that the product exhibited "slight adhesion" in its heat resistance and a grade of 0 in its adhesion. However, due to an excessively high polyurethane ratio, the ink film became too flexible and prone to adhesion at high temperatures. Conversely, if the acrylic acid content was excessive, the ink film would become brittle, reducing its adhesion. This demonstrates that the resin ratio in this invention is crucial for balancing performance.

[0052] Comparative Example 5 The raw materials and dosages in this comparative example are the same as those in Example 1, except that in step S4, the rotation speed is changed to 1000 rpm, and the composite anti-adhesion agent is added slowly.

[0053] Testing revealed that the anti-adhesion property decreased to "slight adhesion." This is because the physical structure of the hollow glass microspheres was damaged under high-speed shear force, causing their "supporting" function to fail and resulting in a decrease in anti-adhesion property. Conversely, if the rotation speed is too low, uneven dispersion of the additives can lead to localized adhesion. This demonstrates that the low-speed process of 300-500 rpm specified in this application can protect the structural integrity of the hollow glass microspheres, thereby ensuring their anti-adhesion function.

[0054] Therefore, this invention relates to a formulation and preparation method of a heat-resistant water-based plastic gravure ink. By designing a ternary composite anti-blocking additive synergistic system and optimizing the formulation process, it achieves 24-hour non-blocking at 60°C and 0.2MPa pressure, meeting the high temperature and high humidity requirements of summer storage and long-distance transportation in tropical and subtropical regions. At the same time, it also has high adhesion, high gloss, good flexibility and storage stability.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A formulation for a heat-resistant, adhesive-resistant water-based plastic gravure ink, characterized in that, By weight, it includes the following components: The composition includes 30-50 parts of waterborne acrylic resin emulsion, 10-20 parts of waterborne polyurethane dispersion, 15-25 parts of coloring pigment, 3-8 parts of composite anti-blocking agent, 0.5-1.5 parts of wetting and dispersing agent, 0.1-0.5 parts of defoamer, 0.2-0.8 parts of leveling agent, 0.5-1.5 parts of pH adjuster, and 10-20 parts of deionized water. The composite anti-adhesion additive is composed of organosilicon-modified wax emulsion, hollow glass microspheres, and cross-linked polyurethane microparticles.

2. The formulation of an anti-heat-blocking water-based plastic gravure ink according to claim 1, characterized in that: In the composite anti-adhesion additive, the weight ratio of organosilicon-modified wax emulsion, hollow glass microspheres, and cross-linked polyurethane microparticles is (2~3):(1~2):

1.

3. The formulation of an anti-heat-blocking water-based plastic gravure ink according to claim 1, characterized in that: The solid content of the organosilicon-modified wax emulsion is 30-40%, and the particle size is ≤100nm; The hollow glass microspheres have an average particle size of 5–20 μm, a wall thickness of 0.5–1.5 μm, and a true density of 0.15–0.30 g / cm³. 3 ; The cross-linked polyurethane microparticles have an average particle size of 0.1~0.5μm and contain 2~3% isocyanate groups.

4. The formulation of a heat-resistant, adhesion-resistant water-based plastic gravure ink according to claim 1, characterized in that: The weight ratio of the aqueous acrylic resin emulsion to the aqueous polyurethane dispersion is (2.5~3.5):

1.

5. The formulation of a heat-resistant, adhesion-resistant water-based plastic gravure ink according to claim 1, characterized in that: The wetting and dispersing agent is a polycarboxylate polymeric dispersant; the defoamer is an organosilicon defoamer; the leveling agent is a polyether-modified siloxane leveling agent; and the pH adjuster is ammonia or dimethylethanolamine.

6. A method for preparing the formulation of the heat-resistant, adhesive-resistant water-based plastic gravure ink as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Premixing stage: Add deionized water to the high-speed disperser, and add wetting and dispersing agent, 50% defoamer and pH adjuster in sequence under stirring. Stir until the solution is clear and transparent. S2, Pigment Dispersion Stage: While maintaining stirring, add coloring pigments and increase the rotation speed to disperse at high speed until the slurry fineness is ≤15μm, thus obtaining the color paste; S3. Paint mixing stage: Reduce the rotation speed and slowly add water-based acrylic resin emulsion, water-based polyurethane dispersion, leveling agent, and the remaining 50% of defoamer to the color paste in sequence, and stir until the system is uniform. S4. Core Additive Addition Stage: Maintain a rotation speed of 300~500 rpm, slowly add the composite anti-blocking additive, and continue stirring for 20~30 minutes to ensure uniform dispersion of the additive; S5. Filtration and curing stage: Filter using a 200-300 mesh filter, then place in a sealed container for static curing to obtain heat-resistant, adhesive-resistant water-based plastic gravure ink.

7. The preparation method according to claim 6, characterized in that: In step S1, the stirring speed is 300~400 rpm and the stirring time is 5~10 min.

8. The preparation method according to claim 6, characterized in that: In step S2, the stirring speed is 1000~1500 rpm and the stirring time is 30~45 min.

9. The preparation method according to claim 6, characterized in that: In step S3, the stirring speed is 400~600 rpm and the stirring time is 15~20 min.

10. The preparation method according to claim 6, characterized in that: In step S5, the curing temperature is 25~27℃ and the resting time is 20~30h.

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