High-adhesion colored high-brightness composite film packaging material

Abstract

The invention relates to the technical field of composite films, and particularly discloses a high-adhesion colored high-brightness composite film packaging material which structurally comprises a bottom film layer and a colored layer compounded on the surface of the bottom film layer, the colored layer is formed by coating and drying a colored coating containing a modified carbon black / crystalline flake graphite compound, polyketone resin, an oily acrylic acid-organic silicon composite resin solution and the like, the modified compound has a composite coating structure of a titanium hydroxyl compound and a silane coupling agent, and the bottom film layer is selected from a specific film and is subjected to corona treatment. The compatibility and the interface bonding force of a compound and resin are enhanced through a composite coating structure, all the components synergistically improve the color development, the brightness and the stability, and an optimized preparation process is matched, so that the material has high glossiness, excellent adhesive force and wear resistance and is suitable for the field of cigarette packaging.

Description

Technical Field

[0001] This invention relates to the field of composite film technology, specifically to a high-adhesion colored high-gloss composite film packaging material. Background Technology

[0002] Composite films, with their diverse performance advantages, have become a key packaging material in the cigarette packaging industry, and their market demand continues to rise. These materials must simultaneously meet the dual requirements of protective function and appearance. Among them, coating fastness and printability are core indicators—coating fastness directly determines the barrier properties, durability, and safety of the packaging, while printability affects the brand recognition and market competitiveness of the product. High-precision color reproduction and pattern clarity are important carriers of brand communication.

[0003] Current composite films mostly employ multi-layered composite structures, achieving basic properties through the combination of a substrate and a functional coating. The substrate is typically a thin film such as PVC or PET, while the coating is formed through a coating process to impart specific functions to the material. However, existing technologies lack systematic solutions in areas such as coating formulation design (e.g., selection of film-forming substances, ratio of functional additives), composite process optimization (e.g., coating parameters, curing conditions), and interfacial bonding enhancement (e.g., substrate surface treatment, interface modification), making it difficult to balance stability and functionality in material performance.

[0004] Existing composite films have defects in practical applications: First, the coating adhesion is insufficient, which easily leads to peeling and cracking, resulting in the failure of the protective function; second, the color development effect of the colored layer is poor, with insufficient brightness and poor color stability, and it is easily affected by temperature and changes color. The root cause of these problems lies in the weak bonding force between the substrate and the coating interface and the insufficient matching of functional components in the coating formulation. Summary of the Invention

[0005] To address the technical deficiencies in the background art, this invention proposes a high-adhesion colored high-gloss composite film packaging material, which solves the aforementioned technical problems and meets practical needs. The specific technical solution is as follows: A high-adhesion colored high-gloss composite film packaging material includes a base film layer and a colored layer laminated on the surface of the base film layer. The colored layer is formed by applying a colored coating to the upper surface of the base film layer and drying it. The colored coating, by weight percentage of the total coating, contains 15-20% modified carbon black / flake graphite composite, 12-15% polyketone resin, 30-40% oil-based acrylic-organic silicone composite resin solution, 8-12% hydrogenated petroleum resin, and the balance being propylene glycol methyl ether acetate. The modified carbon black / flake graphite composite has a titanium hydroxyl-silane coupling agent composite coating layer on its surface, and the modified carbon black / flake graphite composite with titanium hydroxyl-silane coupling agent composite coating layer is also surface modified with a phosphate ester dispersant.

[0006] As a further technical solution of the present invention, the bottom film layer is selected from any one of PVC film, PET film, OPP film, and BOPP film, the thickness of the bottom film layer is 12-16μm, and the bottom film layer is subjected to corona treatment before being coated with colored paint.

[0007] As a further technical solution of the present invention, the modified carbon black / flake graphite composite is prepared by the following process: (a) Carbon black and flake graphite are mixed at a mass ratio of 10:(1-3) to obtain a carbon black / flake graphite mixture; (b) The carbon black / flake graphite obtained in step (a) is mixed with anhydrous ethanol at a mass ratio of (1-2):10 to prepare a mixture / ethanol suspension. Under ultrasonic dispersion at 30-40 kHz and mechanical stirring, the temperature is raised to 50-70 °C, and a solution prepared by alkoxytitanate and anhydrous ethanol at a volume ratio of 1:1 is slowly added dropwise. After the addition is completed, the temperature is maintained, and deionized water is slowly added dropwise. After the addition is completed, the reaction continues for 1-2 h. (c) Add a solution prepared by epoxy silane coupling agent and anhydrous ethanol in a 1:1 volume ratio to the system obtained in step (b), and add glacial acetic acid at the same time to adjust the pH value of the system to 4-5 to obtain intermediate slurry. (d) After spray drying, the intermediate slurry is used to obtain intermediate powder. The intermediate powder is mixed with phosphate ester dispersant and then subjected to high-speed shearing to obtain modified carbon black / flake graphite composite.

[0008] As a further technical solution of the present invention, in step (b), the alkoxytitanate is tetraisopropyl titanate or tetrabutyl titanate, the amount of alkoxytitanate weighed is 2-5% of the total mass of carbon black and flake graphite, and the amount of deionized water added is 1.2-1.5 times that of the mixture / ethanol suspension.

[0009] As a further technical solution of the present invention, in step (c), the epoxy silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane, and the amount of epoxy silane coupling agent added is 2-8% of the total mass of carbon black and flake graphite.

[0010] As a further technical solution of the present invention, in step (d), the intermediate slurry obtained in step (c) is cooled to below 60°C and then spray-dried. The inlet temperature of the spray dryer is 180°C and the outlet temperature is 80°C to obtain intermediate powder. The intermediate powder is placed in a high-speed shearing device, and 1% of the total mass of the intermediate powder phosphate ester dispersant BYK-110 is slowly added while stirring. After the addition is completed, the device is sheared at 5000±500rpm for 30min.

[0011] As a further technical solution of the present invention, the preparation method of the oily acrylic-organic silicone composite resin solution is as follows: Toluene and PMA are mixed in a ratio of 2:1 to obtain a toluene / PMA mixed solvent. 17.5 parts of the toluene / PMA mixed solvent are added to a four-necked flask equipped with a condenser, dropping funnel, and thermometer. The temperature is raised to 80-85°C. 30 parts of methyl methacrylate, 15 parts of butyl acrylate, 5 parts of styrene, 10 parts of vinyltrimethoxysilane, and 17.5 parts of toluene / PMA are then mixed. The solvent and 0.5 parts of AIBN initiator are mixed evenly to prepare a monomer premix. 15% of the monomer premix is ​​added to the reactor and reacted for 15-20 minutes. The remaining monomer premix is ​​then slowly added dropwise, with the dropping rate controlled to be completed within 3-4 hours. The temperature is maintained. After the addition is complete, 0.5 parts of AIBN initiator are added, the temperature is raised to 85-90℃, and the temperature is maintained for 2-3 hours to ensure the reaction is complete. Then the temperature is lowered to below 40℃, and the mixture is filtered to obtain a clear and transparent oily acrylic-organic silicone composite resin solution.

[0012] As a further technical solution of the present invention, the colored layer coating step is as follows: the polyketone resin and the oily acrylic-organic silicone composite resin solution are stirred at 800 rpm for 20 min at 40±5℃, the modified carbon black / flake graphite composite is added, and the mixture is stirred at 1200 rpm for 40 min. After vacuum degassing at -0.08 MPa for 30 min, the mixture is coated onto the surface of the corona-treated base film layer.

[0013] As a further technical solution of the present invention, the preparation method is as follows: the colored coating is wet-coated onto the base film layer, dried at a temperature of 150-160℃ for 5-10s to form a 1-5μm colored layer, and then cured at 35-45℃ for 24-48h.

[0014] The beneficial effects of this invention are as follows: The modified carbon black / flake graphite composite used in this invention, through a "titanium-coupling agent" composite coating structure and retaining some hydroxyl groups, enhances the compatibility with polyketone resin and oil-based acrylic-organic silicone composite resin solution. Furthermore, the silane bridging layer improves the interfacial bonding between the substrate and the coating, significantly increasing the adhesion of the colored layer and reducing peeling and cracking. Simultaneously, the coating components in the colored layer work synergistically to improve the color rendering effect, increase brightness, and enhance color stability. Combined with optimized coating, drying, and curing processes, this ensures stable material performance, balancing functionality and stability. It meets the high requirements for durability, safety, and appearance of cigarette packaging materials, thereby enhancing product brand recognition and market competitiveness. Detailed Implementation

[0015] The embodiments of the present invention will be described below with reference to relevant examples. The embodiments of the present invention are not limited to the following examples, and the present invention relates to relevant necessary components in this technical field, which should be regarded as well-known technology in this technical field and can be known and mastered by those skilled in this technical field.

[0016] A high-adhesion colored high-gloss composite film packaging material includes a base film layer and a colored layer laminated on the surface of the base film layer. The colored layer is formed by applying a colored coating to the upper surface of the base film layer and then drying it. The colored coating, by weight percentage of the total coating, contains 15-20% modified carbon black / flake graphite composite, 12-15% polyketone resin, 30-40% oil-based acrylic-silicone composite resin solution, 8-12% hydrogenated petroleum resin, and 13-35% propylene glycol methyl ether acetate. The modified carbon black / flake graphite composite has a titanium hydroxyl-silane coupling agent composite coating layer on its surface, and the modified carbon black / flake graphite composite with titanium hydroxyl-silane coupling agent composite coating layer is also surface modified with a phosphate ester dispersant.

[0017] The modified carbon black / flake graphite composite of this invention features a titanium-coupling agent composite coating structure, enabling it to form a tighter bond with polyketide resin and oil-based acrylic-silicone composite resin solution, thus enhancing compatibility. This excellent compatibility results in a more uniform distribution of coating components and a more stable structure. The silane bridging layer also improves the interfacial adhesion between the substrate and the coating, thereby significantly improving the adhesion of the colored layer and effectively reducing peeling and cracking.

[0018] In terms of color rendering and brightness, the components of the colored coating work synergistically. The modified carbon black / flake graphite composite exhibits good dispersibility in the system formed by polyketone resin and oily acrylic-organic silicone composite resin solution, fully demonstrating its coloring ability. Polyketone resin provides a stable carrier environment for the colored components, while the oily acrylic-organic silicone composite resin solution, with its film-forming properties, makes the surface of the colored layer smoother and more even, improving the light reflection effect, thereby enhancing the brightness and color performance of the colored layer and making the colors more vivid.

[0019] The improved color stability of this invention also benefits from the synergy of its components. The modified carbon black / flake graphite composite exhibits excellent inherent stability, and the coating structure formed by the polyketone resin and the oil-based acrylic-silicone composite resin solution is dense, effectively blocking the influence of external factors such as temperature. Furthermore, optimized coating, drying, and curing processes ensure thorough integration of the components, further enhancing the temperature resistance of the colored layer, reducing discoloration caused by temperature changes, and guaranteeing color stability.

[0020] As one of the preferred embodiments of the present invention, the bottom film layer is selected from any one of PVC film, PET film, OPP film, and BOPP film, the thickness of the bottom film layer is 12-16μm, and the bottom film layer is subjected to corona treatment before being coated with colored paint.

[0021] Specifically, the bottom film layer is preferably a BOPP film with a thickness of 14μm.

[0022] The bottom layer uses PVC, PET, OPP, or BOPP film because these films possess excellent mechanical strength, temperature resistance, and chemical stability, providing reliable support for the composite film and meeting the requirements of cigarette packaging for tensile strength and storage durability. The thickness is set at 12-16μm, a result of comprehensive consideration of protective performance and processing suitability: too thin and it is prone to breakage due to mechanical stress, too thick and it increases material rigidity, affecting packaging formation. A 14μm thick BOPP film is preferred because it combines good flexibility and stiffness within this range, and its high transparency and gloss enhance the overall high-gloss effect in conjunction with the colored layer, better meeting the appearance requirements of cigarette packaging.

[0023] Corona treatment before coating is a key pretreatment step. High-frequency high-voltage discharge generates polar groups on the surface of the substrate and forms a micro-rough structure, which greatly increases the surface tension, making it easier for colored coatings to spread and penetrate. This strengthens the interfacial bonding between the coating and the substrate and avoids delamination problems during subsequent use.

[0024] As one of the preferred embodiments of the present invention, the modified carbon black / flake graphite composite is prepared by the following process: (a) Carbon black and flake graphite are mixed at a mass ratio of 10:(1-3) to obtain a carbon black / flake graphite mixture; (b) The carbon black / flake graphite obtained in step (a) is mixed with anhydrous ethanol at a mass ratio of (1-2):10 to prepare a mixture / ethanol suspension. Under ultrasonic dispersion at 30-40 kHz and mechanical stirring, the temperature is raised to 50-70 °C, and a solution prepared by alkoxytitanate and anhydrous ethanol at a volume ratio of 1:1 is slowly added dropwise. After the addition is completed, the temperature is maintained, and deionized water is slowly added dropwise. After the addition is completed, the reaction continues for 1-2 h. (c) Add a solution prepared by epoxy silane coupling agent and anhydrous ethanol in a 1:1 volume ratio to the system obtained in step (b), and add glacial acetic acid at the same time to adjust the pH value of the system to 4-5 to obtain intermediate slurry. (d) After spray drying, the intermediate slurry is used to obtain intermediate powder. The intermediate powder is mixed with phosphate ester dispersant and then subjected to high-speed shearing to obtain modified carbon black / flake graphite composite.

[0025] The modified carbon black / flake graphite composite has a "titanium hydroxyl-silane coupling agent" composite coating structure. The inner coating formed by the titanium hydroxyl compound can enhance the bonding force between particles by binding the hydroxyl groups to the surface groups of carbon black and flake graphite. The outer silane coupling agent improves the compatibility of the composite with the resin components in the coating through chemical bridging. The dual structure synergistically solves the problems of easy agglomeration and weak bonding with the matrix of traditional carbon black.

[0026] Specifically, in the preparation process, carbon black and flake graphite are mixed at a mass ratio of 10:2 to obtain a carbon black / flake graphite mixture; the carbon black / flake graphite mixture obtained in step (a) is mixed with anhydrous ethanol at a mass ratio of 1.5:10 to prepare a mixture / ethanol suspension. Under ultrasonic dispersion at 35 kHz and mechanical stirring, the temperature is raised to 60°C, and a solution prepared by alkoxy titanate and anhydrous ethanol at a volume ratio of 1:1 is slowly added dropwise. After the addition is complete, the temperature is maintained, and deionized water is slowly added dropwise. After the addition is complete, the reaction continues for 1.5 h; a solution prepared by epoxy silane coupling agent and anhydrous ethanol at a volume ratio of 1:1 is added to the system obtained in step (b), and glacial acetic acid is added to adjust the pH value of the system to 4.5 to obtain an intermediate slurry; the intermediate slurry is spray-dried to obtain an intermediate powder, and the intermediate powder is mixed with a phosphate ester dispersant and subjected to high-speed shearing treatment to obtain a modified carbon black / flake graphite composite.

[0027] Before spray drying, the epoxy silane coupling agent in step (c) has undergone a condensation reaction with the titanium hydroxyl layer through the trimethoxysilane group, initially constructing a "titanium-silicon" connection. During spray drying, the inlet temperature of 180°C rapidly evaporates the ethanol and water in the system, causing the slurry to instantly turn into powder, while the outlet temperature of 80°C prevents the powder from overheating. This prevents the decomposition of the formed "titanium hydroxyl-coupling agent" coating structure and allows the coupling agent to be more tightly fixed on the outer layer of the titanium hydroxyl group, while retaining its epoxy activity. This process also reduces particle agglomeration, resulting in better dispersion of the intermediate powder, creating conditions for subsequent high-speed shear mixing with the phosphate ester dispersant, further enhancing the coupling effect of the coupling agent on the carbon black / flake graphite mixture and the titanium hydroxyl compound, ultimately ensuring the dispersion of the composite in the coating and its compatibility with the resin.

[0028] As one of the preferred embodiments of the present invention, in step (b), the alkoxytitanate is tetraisopropyl titanate or tetrabutyl titanate, the amount of alkoxytitanate weighed is 2-5% of the total mass of carbon black and flake graphite, and the amount of deionized water added is 1.2-1.5 times that of the mixture / ethanol suspension.

[0029] Specifically, the preferred alkoxy titanate is tetraisopropyl titanate, which is weighed at 3.5% of the total mass of carbon black and flake graphite, and the amount of deionized water added is 1.35 times that of the mixture / ethanol suspension.

[0030] In step (b), tetraisopropyl titanate or tetrabutyl titanate is selected as the alkoxy titanate because both have moderate hydrolysis rates and can be uniformly dispersed under ultrasonic treatment at 30-40 kHz. The amount of deionized water added is 1.35 times that of the mixture / ethanol suspension. When reacting at 50-70℃, it can gradually hydrolyze to generate titanium hydroxyl groups, part of which uniformly coats the surface of the carbon black / flake graphite mixture, and the other part is coated onto the surface of the carbon black / flake graphite mixture through the coupling effect of epoxy silane coupling agent, thereby enhancing the coating effect.

[0031] The dosage is set at 2-5% of the total mass of carbon black and flake graphite. If the addition is less than 2%, the titanium hydroxyl groups generated by the hydrolysis of titanate will be insufficient, failing to form a complete and continuous inner layer coating, affecting the subsequent bonding stability with the silane coupling agent. If the addition is greater than 5%, excess titanate will not participate in the reaction and will remain free in the system, increasing costs and potentially causing particle agglomeration in subsequent steps, reducing the dispersibility of the composite in the coating, and thus affecting coating performance. This dosage range ensures an appropriate titanium hydroxyl layer thickness, providing a stable substrate for the outer silane coating.

[0032] As one of the preferred embodiments of the present invention, in step (c), the epoxy silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane, and the amount of epoxy silane coupling agent added is 2-8% of the total mass of carbon black and flake graphite.

[0033] Specifically, the amount of epoxy silane coupling agent added is 5% of the total mass of carbon black and flake graphite.

[0034] In step (c), γ-glycidoxypropyltrimethoxysilane is selected as an epoxy silane coupling agent because its molecular structure contains both epoxy and trimethoxysilane groups: the epoxy group can react chemically with the hydroxyl and carboxyl groups of polyketide resin and oily acrylic-organic silicone composite resin solution in the coating system to form stable chemical bonds; the trimethoxysilane group can undergo a condensation reaction with the titanium hydroxyl layer generated in step (b) to construct a composite coating structure with "titanium-silicon" covalent connection, thereby strengthening the integrity of the coating layer.

[0035] The addition amount is set at 2-8% of the total mass of carbon black and flake graphite, based on the optimization of coating integrity and reaction efficiency: below 2%, the silane coupling agent is insufficient, failing to form a continuous outer layer and affecting compatibility with the resin; above 8%, excessive silane is prone to self-polymerization, leading to particle agglomeration and reduced dispersibility. The preferred addition amount is 5%, which can form a uniform and dense outer coating, ensuring sufficient reaction with the titanium hydroxyl layer and providing sufficient epoxy groups to bind with the subsequent resin, thus balancing interfacial bonding and dispersion stability.

[0036] As one of the preferred embodiments of the present invention, in step (d), the intermediate slurry obtained in step (c) is cooled to below 60°C and then spray-dried. The inlet temperature of the spray dryer is 180°C and the outlet temperature is 80°C to obtain intermediate powder. The intermediate powder is placed in a high-speed shearing device, and 1% of the total mass of the intermediate powder phosphate ester dispersant (BYK-110) is slowly added while stirring. After the addition is completed, the device is sheared at 5000±500 rpm for 30 minutes.

[0037] In step (d), cooling the intermediate slurry to below 60°C before spray drying avoids damage to the formed "titanium-silicon" composite coating structure due to high temperatures, prevents the decomposition of the silane coupling agent or titanium hydroxyl layer, and ensures the integrity of the coating. The spray drying inlet temperature of 180°C allows for rapid evaporation of moisture, causing the slurry to instantly turn into powder; the outlet temperature of 80°C prevents the powder from overheating and causing agglomeration, while ensuring thorough drying and obtaining well-dispersed intermediate powder.

[0038] Adding 1% of phosphate dispersant BYK-110 inhibits particle agglomeration through steric hindrance, improving the dispersion stability of the composite in the coating. High-speed shearing treatment breaks down potential agglomerates with strong shear force, allowing the coupling agent and dispersant to uniformly coat the powder surface, refining the particle size, and ultimately ensuring uniform dispersion of the composite in the coating.

[0039] As one of the preferred embodiments of the present invention, the preparation method of the oily acrylic-organic silicone composite resin solution is as follows: Toluene and PMA are mixed in a ratio of 2:1 to obtain a toluene / PMA mixed solvent. 17.5 parts of the toluene / PMA mixed solvent are added to a four-necked flask equipped with a condenser, dropping funnel, and thermometer. The temperature is raised to 80-85°C. 30 parts of methyl methacrylate, 15 parts of butyl acrylate, 5 parts of styrene, 10 parts of vinyltrimethoxysilane, and 17.5 parts of toluene / PMA are then mixed... The solvent and 0.5 parts of AIBN initiator are mixed evenly to prepare a monomer premix. 15% of the monomer premix is ​​added to the reactor and reacted for 15-20 minutes. The remaining monomer premix is ​​then slowly added dropwise, with the dropping rate controlled to be completed within 3-4 hours. The temperature is maintained. After the addition is complete, 0.5 parts of AIBN initiator are added, the temperature is raised to 85-90℃, and the temperature is maintained for 2-3 hours to ensure the reaction is complete. Then the temperature is lowered to below 40℃, and the mixture is filtered to obtain a clear and transparent oily acrylic-organic silicone composite resin solution.

[0040] Methyl methacrylate (MMA) provides a rigid framework for the resin, giving the coating sufficient hardness; butyl acrylate (BA) introduces flexible segments, balancing hardness and flexibility and preventing the coating from becoming brittle; styrene further enhances the resin's chemical resistance and structural stability; while the vinyl group of vinyltrimethoxysilane (VTMS) can participate in free radical polymerization, forming covalent bonds with other monomers, which not only improves the resin's weather resistance but also enhances its compatibility with modified carbon black / flake graphite composites and strengthens interfacial bonding.

[0041] The oily acrylic-organosilicon composite resin solution prepared by the above method combines the excellent film-forming properties of acrylic resin with the surface smoothness and weather resistance brought by organosilicon groups. The polar groups and silicon-oxygen bonds uniformly distributed in its molecular chain can form multiple forces with the hydroxyl and epoxy groups in polyketone resin and modified carbon black / flake graphite composite, which not only provides a stable carrier framework for the colored layer, but also enhances light reflection through the smooth film-forming characteristics, directly contributing to the improvement of the high gloss effect and adhesion of the composite film.

[0042] As one of the preferred embodiments of the present invention, the colored layer coating step is as follows: the polyketone resin and the oily acrylic-organic silicone composite resin solution are stirred at 800 rpm for 20 min at 40±5℃, the modified carbon black / flake graphite composite is added, and the mixture is stirred at 1200 rpm for 40 min. After vacuum degassing at -0.08 MPa for 30 min, the mixture is coated onto the surface of the corona-treated base film layer.

[0043] This coating step ensures a uniform and stable colored layer by controlling process parameters in stages. First, the polyketone resin and the oil-based acrylic-silicone composite resin solution are stirred at 800 rpm for 20 minutes at 40°C. This temperature promotes the movement of molecular chains in both resins, enhancing compatibility. Medium-speed stirring avoids excessive shearing that could damage the resin structure, forming a uniform film-forming matrix. After adding the modified carbon black / flake graphite composite, the stirring speed is increased to 1200 rpm and the stirring time is extended to 40 minutes. The strong shear force breaks down potential agglomerations of the composite, allowing it to be uniformly dispersed in the resin matrix, ensuring consistent coloring and uniform brightness.

[0044] Vacuum degassing at -0.08MPa for 30 minutes effectively removes air bubbles generated by stirring, preventing pinholes or depressions in the coating and ensuring surface smoothness. The final coating layer, applied after corona treatment, utilizes the polar groups on the substrate surface to form stronger chemical bonds with the coating resin, synergistically enhancing interfacial adhesion and laying the foundation for high adhesion and high gloss after subsequent drying and curing.

[0045] As one of the preferred embodiments of the present invention, the preparation method is as follows: a colored coating is wet-coated onto a base film layer, dried at a temperature of 150-160℃ for 5-10s to form a 1-5μm colored layer, and then cured at 35-45℃ for 24-48h.

[0046] Specifically, the colored coating is wet-coated onto a 14μm base film layer, dried at 160℃ for 5 seconds to form a 1.5μm colored layer, and then cured at 40℃ for 36 hours.

[0047] In the above preparation method, a drying temperature of 160℃ can quickly evaporate the propylene glycol methyl ether solvent and water in the coating, avoiding coating sagging or uneven thickness caused by slow drying; the 5-second drying time ensures thorough drying while preventing prolonged high temperature from damaging the film-forming structure of the oily acrylic-silicone composite resin solution and the coating layer of the modified carbon black / flake graphite composite, thus ensuring the stability of the coating composition. The subsequent curing at 40℃ for 36 hours promotes further cross-linking of resin molecules inside the coating through gentle heating, strengthening the chemical bond between polyketone resin, oily acrylic-silicone composite resin solution and modified composite, while eliminating internal stress generated during coating, making the coating and the base film layer more tightly bonded, ultimately improving the overall material's adhesion, temperature resistance and color stability, meeting the long-term use requirements of cigarette packaging materials.

[0048] The technical solution of the present invention will be further described below through embodiments and comparative examples.

[0049] Example 1 A method for preparing a high-adhesion colored high-gloss composite film packaging material, comprising the following steps: S1. Preparation of modified carbon black / flake graphite composite: Carbon black and flake graphite were mixed at a mass ratio of 10:2 to obtain a carbon black / flake graphite mixture. The carbon black / flake graphite mixture obtained in step (a) was then mixed with anhydrous ethanol at a mass ratio of 1.5:10 to prepare a mixture / ethanol suspension. Under ultrasonic dispersion at 35 kHz and mechanical stirring, the mixture was heated to 60 °C, and a solution prepared by mixing tetraisopropyl titanate and anhydrous ethanol at a volume ratio of 1:1 was slowly added dropwise. After the addition was complete, the amount of tetraisopropyl titanate weighed was 3.5% of the total mass of carbon black and flake graphite. While maintaining the temperature, deionized water was slowly added dropwise at a volume 1.35 times that of the mixture / ethanol suspension. After the addition was complete, the reaction was continued for 1.5 minutes. h; Add a solution prepared by epoxy silane coupling agent and anhydrous ethanol in a 1:1 volume ratio to the system obtained in step (b), and add glacial acetic acid to adjust the pH of the system to 4.5 to obtain an intermediate slurry; After spray drying the intermediate slurry, obtain intermediate powder, cool the intermediate slurry to below 60°C, and spray dry it at an inlet temperature of 180°C and an outlet temperature of 80°C to obtain intermediate powder; Mix the powder with 1% of the total mass of the powder phosphate dispersant BYK-110, and shear at 5000 rpm for 30 min to obtain a modified carbon black / flake graphite composite.

[0050] S2. Colored coating and curing: A mixture of 13.5% polyketone resin, 35% oily acrylic-silicone composite resin solution, 10% hydrogenated petroleum resin, and 24% propylene glycol methyl ether acetate was stirred at 800 rpm for 20 min at 40 °C. Then, 17.5% modified carbon black / flake graphite composite was added, and the mixture was stirred at 1200 rpm for 40 min. The mixture was then degassed under vacuum at -0.08 MPa for 30 min and coated onto a 14 μm corona-treated BOPP film surface. The film was then dried at 150 °C for 5 s to form a 1.5 μm colored layer and then cured at 40 °C for 36 h.

[0051] Example 2 The difference between Example 2 and Example 1 is that: a 14μm PET film is used instead of a BOPP film for the bottom film layer; the amount of modified composite is adjusted to 15%; the curing time is shortened to 24h, and the remaining steps are the same as in Example 1.

[0052] Example 3 The difference between Example 3 and Example 1 is as follows: the thickness of the bottom film layer is adjusted to 12 μm; the ratio of carbon black to flake graphite is adjusted to 10:3; tetrabutyl titanate is used as the alkoxy titanate; the thickness of the colored layer is adjusted to 1 μm; the curing temperature is increased to 45°C and the time is extended to 48 h; the remaining steps are the same as in Example 1.

[0053] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the modified composite uses an uncoated carbon black / graphite mixture (carbon black: graphite = 10:2), omitting the titanate and silane coupling agent coating process in step S1, and the remaining steps are the same as in Example 1.

[0054] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the modified composite is only coated with tetraisopropyl titanate, and the silane coupling agent treatment in step (c) of step S1 is omitted. The remaining steps are the same as in Example 1.

[0055] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the ratio of carbon black to flake graphite was adjusted to 10:0.5, while the remaining steps were the same as in Example 1.

[0056] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the oily acrylic-silicone composite resin solution was replaced with a common solvent-based acrylic resin, and the remaining steps were the same as in Example 1.

[0057] Performance testing The gloss of the colored layer was tested according to the description in standard GB / T 9754-2007.

[0058] The adhesion strength of colored layers was tested according to the standard GB / T 13217.7-2023 (a total of six grades, from 0 to 5, with grade 0 being the best).

[0059] A friction fastness tester was used to rub the sample under a load of 200g, observe the peeling of the ink layer, and record the maximum number of rubbing cycles.

[0060] The test results are shown in the table below:

[0061] By comparing the performance data of the examples and the comparative examples, the following conclusions can be drawn: In Comparative Example 1, the carbon black / graphite mixture without alkoxytitanate and silane coupling agent coating had a gloss of only 45 GU (far lower than 92 GU in Example 1), an adhesion grade of 5 (Grade 1 in Example 1), and a maximum abrasion resistance of only 10 cycles (110 cycles in Example 1). This indicates that the composite coating structure significantly improves the uniformity, stability, and adhesion performance of the coating by enhancing the compatibility and interfacial bonding between the composite and the resin. In Comparative Example 2, when only alkoxytitanate coating was performed without silane treatment, the gloss dropped to 75 GU, the adhesion grade was 3, and the abrasion resistance was 30 cycles. This shows that the bridging effect of the outer silane coupling agent is key to the synergistic performance improvement, and the lack of silane leads to the loss of the synergistic effect of the coating structure.

[0062] In Comparative Example 3, after adjusting the ratio of carbon black to flake graphite to 10:0.5, the gloss decreased to 68 GU, the adhesion grade was 4, and the abrasion resistance was only 15 cycles. This indicates that the flake structure of flake graphite plays an important role in improving the density and gloss of the coating, and an excessively low ratio will weaken these advantages and affect the dispersion of the composite and the performance of the coating.

[0063] In Comparative Example 4, after replacing the oil-based acrylic-silicone emulsion with a regular acrylic emulsion, the gloss decreased to 78 GU, the adhesion grade was 3, and the abrasion resistance was 40 cycles. This indicates that the silicone-modified emulsion, through its film-forming properties (such as surface smoothness) and the weather resistance of the silicon-oxygen bonds, can effectively improve the gloss and density of the coating, while regular emulsions cannot achieve the same effect.

[0064] The comparison of Examples 1-3 shows that, within a reasonable range of adjustments to parameters such as the base film material (BOPP, PET), composite content (15-20%), base film thickness (12-16μm), graphite ratio (10:1-3), titanate type (tetraisopropyl or tetrabutyl), and curing conditions (temperature 35-45℃, time 24-48h), the composite film can still maintain good overall performance (gloss ≥88GU, adhesion ≤2 grade, abrasion resistance ≥85 times), indicating that the formulation and process have a certain degree of adaptability.

[0065] Finally, the best performance was achieved under the parameter combination of Example 1 (14μm BOPP film, 17.5% modified carbon black / flake graphite composite, 10:2 carbon black:graphite ratio, tetraisopropyl titanate coating, 5% silane coupling agent, 1.5μm colored layer, drying at 160℃ for 5 s, and curing at 40℃ for 36 h). At this time, the gloss reached 92 GU, the adhesion was grade 1, and the abrasion resistance was 110 times. All performances were optimal, verifying the rationality of the preferred scheme.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-adhesion colored high-gloss composite film packaging material, comprising a base film layer and a colored layer laminated on the surface of the base film layer, characterized in that, The colored layer is formed by applying a colored coating to the surface of the base film layer and drying it. The colored coating, by weight percentage of the total coating, contains 15-20% modified carbon black / flake graphite composite, 12-15% polyketone resin, 30-40% oil-based acrylic-organic silicone composite resin solution, 8-12% hydrogenated petroleum resin, and the balance is propylene glycol methyl ether acetate. The modified carbon black / flake graphite composite has a titanium hydroxyl-silane coupling agent composite coating layer on its surface, and the modified carbon black / flake graphite composite with titanium hydroxyl-silane coupling agent composite coating layer is also surface modified with a phosphate ester dispersant.

2. The high-adhesion colored high-gloss composite film packaging material according to claim 1, characterized in that, The base film layer is selected from any one of PVC film, PET film, OPP film, and BOPP film. The thickness of the base film layer is 12-16μm. The base film layer is subjected to corona treatment before being coated with colored paint.

3. The high-adhesion colored high-gloss composite film packaging material according to claim 1 or 2, characterized in that, The modified carbon black / flake graphite composite is prepared by the following process: (a) Carbon black and flake graphite are mixed at a mass ratio of 10:(1-3) to obtain a carbon black / flake graphite mixture; (b) The carbon black / flake graphite obtained in step (a) is mixed with anhydrous ethanol at a mass ratio of (1-2):10 to prepare a mixture / ethanol suspension. Under ultrasonic dispersion at 30-40 kHz and mechanical stirring, the temperature is raised to 50-70 °C, and a solution prepared by alkoxytitanate and anhydrous ethanol at a volume ratio of 1:1 is slowly added dropwise. After the addition is completed, the temperature is maintained, and deionized water is slowly added dropwise. After the addition is completed, the reaction continues for 1-2 h. (c) Add a solution prepared by epoxy silane coupling agent and anhydrous ethanol in a 1:1 volume ratio to the system obtained in step (b), and add glacial acetic acid at the same time to adjust the pH value of the system to 4-5 to obtain intermediate slurry. (d) After spray drying, the intermediate slurry is used to obtain intermediate powder. The intermediate powder is mixed with phosphate ester dispersant and then subjected to high-speed shearing to obtain modified carbon black / flake graphite composite.

4. The high-adhesion colored high-gloss composite film packaging material according to claim 3, characterized in that, In step (b), the alkoxytitanate is tetraisopropyl titanate or tetrabutyl titanate, the amount of alkoxytitanate weighed is 2-5% of the total mass of carbon black and flake graphite, and the amount of deionized water added is 1.2-1.5 times that of the mixture / ethanol suspension.

5. The high-adhesion colored high-gloss composite film packaging material according to claim 3 or 4, characterized in that, In step (c), the epoxy silane coupling agent is γ-glycidyl etheroxypropyltrimethoxysilane, and the amount of epoxy silane coupling agent added is 2-8% of the total mass of carbon black and flake graphite.

6. The high-adhesion colored high-gloss composite film packaging material according to any one of claims 3 to 5, characterized in that, In step (d), the intermediate slurry obtained in step (c) is cooled to below 60°C and then spray-dried. The inlet temperature of the spray dryer is 180°C and the outlet temperature is 80°C to obtain intermediate powder. The intermediate powder is placed in a high-speed shearing device, and 1% of the total mass of the intermediate powder phosphate ester dispersant (BYK-110) is slowly added while stirring. After the addition is completed, the device is sheared at 5000±500 rpm for 30 minutes.

7. The high-adhesion colored high-gloss composite film packaging material according to claim 1, characterized in that, The preparation method of the oily acrylic-organic silicone composite resin solution is as follows: Toluene and PMA were mixed in a 2:1 ratio to obtain a toluene / PMA mixed solvent. 17.5 parts of the toluene / PMA mixed solvent were added to a four-necked flask equipped with a condenser, dropping funnel, and thermometer. The temperature was raised to 80-85℃. 30 parts of methyl methacrylate, 15 parts of butyl acrylate, 5 parts of styrene, 10 parts of vinyltrimethoxysilane, 17.5 parts of the toluene / PMA mixed solvent, and 0.5 parts of AIBN initiator were mixed evenly to prepare a monomer premix. 15% of the monomer premix was added to the reactor first, and the reaction was allowed to proceed for 15-20 minutes. The remaining monomer premix was then slowly added dropwise, controlling the dropping rate to complete the reaction within 3-4 hours while maintaining the temperature. After the addition was complete, 0.5 parts of AIBN initiator were added, and the temperature was raised to 85-90℃ and maintained for 2-3 hours to ensure complete reaction. The temperature was then lowered to below 40℃, and the mixture was filtered to obtain a clear and transparent oily acrylic-organosilicon composite resin solution.

8. The high-adhesion colored high-gloss composite film packaging material according to claim 1, characterized in that, The colored layer coating step is as follows: the polyketone resin and the oily acrylic-organic silicone composite resin solution are stirred at 800 rpm for 20 min at 40±5℃, the modified carbon black / flake graphite composite is added, and the mixture is stirred at 1200 rpm for 40 min. After vacuum degassing at -0.08 MPa for 30 min, the mixture is coated onto the surface of the corona-treated base film layer.

9. The high-adhesion colored high-gloss composite film packaging material according to claim 8, characterized in that, The preparation method is as follows: the colored coating is wet-coated onto the base film layer, dried at 150-160℃ for 5-10s to form a 1-5μm colored layer, and then cured at 35-45℃ for 24-48h.

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