Manufacturing process of high-fastness colored high-brightness composite film packaging material

Abstract

The invention relates to the technical field of composite films, and particularly discloses a high-fastness colored high-brightness composite film packaging material manufacturing process which comprises the steps of S1, base film preparation and pretreatment, S2, surface activation treatment, S3, colored coating preparation, S4, coating, S5, gradient drying and curing and S6, curing. Through corona and twice plasma treatment of different gases, oxygen-containing, amino and fluorine-containing groups are synergistically introduced to the surface of a base membrane, the chemical bonding and hydrogen bonding effects of a coating and the base membrane are enhanced, a composite system of epoxy resin, hydroxy acrylic resin and polyurea resin is adopted, and modified carbon black with the aminated surface is matched, so that the coating has a good anti-corrosion effect on the surface of the base membrane. Under the action of a catalyst and a cross-linking agent, a compact chemical cross-linking and hydrogen bond physical cross-linking dual-network structure is formed; and gradient heating drying and low-temperature curing processes are combined, so that stable volatilization of the solvent and full and complete cross-linking reaction are ensured, and the adhesive force and wear resistance of the base film and the coating layer are effectively improved.

Description

Technical Field

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

[0002] Composite films for packaging have been widely used in many fields, including food, cigarette packaging, and electronics, due to their advantages such as lightweight, good barrier properties, and convenient processing. From sealed packaging bags for snacks to outer wrapping of cigarette boxes, and protective packaging for electronic components, composite films not only protect the contents from moisture, pollution, and mechanical damage, but their surface color and gloss also directly affect the visual appeal of the product, becoming an important carrier for enhancing the added value of goods. The market demand for composite films that combine stable performance and aesthetic effects is growing day by day.

[0003] Traditional colored composite film manufacturing processes typically use polyester (PET) or polypropylene (PP) as the base film. The pretreatment stage usually involves only simple dust removal and a single corona treatment, aiming to initially improve the surface activity of the base film. The coating is usually prepared by mixing a single resin and pigment, and then applied to the surface of the base film by roller coating or blade coating. After that, it is cured by a single-stage drying process. Some processes add a short curing step to promote coating stability. The overall process is relatively simplified, focusing on production efficiency and cost control.

[0004] However, traditional processes have shortcomings. The problem lies in the insufficient adhesion between the coating and the base film. Simple corona treatment introduces a limited number of active groups with poor stability. The resin and the base film surface lack strong interaction. In addition, the resin system in the coating has a low degree of cross-linking, making it difficult to form a dense and stable bonded structure during curing. This leads to problems such as coating peeling and wear in subsequent processing or use of the composite film. This not only affects the appearance but may also cause the protective function to be lost due to coating damage, making it unable to meet the packaging requirements of scenarios such as cigarette packaging and restricting the application of composite films in the high-end packaging field. Summary of the Invention

[0005] To address the technical deficiencies in the background art, this invention proposes a manufacturing process for a high-fastness, 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 manufacturing process for a high-fastness, colored, high-gloss composite film packaging material includes the following steps: S1. Base film preparation and pretreatment: Select polyester PET or polypropylene PP film as the base film, and perform static electricity removal and ultrasonic cleaning on it. S2. Surface activation treatment: The pretreated base film is subjected to corona treatment, first plasma treatment and second plasma treatment in sequence; the first plasma treatment uses ammonia as the working gas to introduce amino groups on the surface of the base film; the second plasma treatment uses carbon tetrafluoride as the working gas to introduce fluorine-containing groups on the surface of the base film. S3. Preparation of colored coating: Epoxy resin, hydroxyl acrylic resin and polyurea resin are dissolved in a solvent and stirred at a high speed of 1000-1500 rpm for 30 min. Modified carbon black and defoamer are added and stirring is continued for 1 h. Finally, crosslinking agent and 2-ethyl-4-methylimidazole are added and stirred at a high speed for 5 min. Impurities are removed by passing the mixture through a 5 μm filter screen. The viscosity of the coating is controlled at 100-300 cP to obtain the colored coating. S4. Coating: The colored coating obtained in step S3 is applied to the surface of the treated base film using a reverse roller coating machine. The coating speed is 50-100m / min and the wet film thickness is 10-20μm. S5. Gradient drying and curing: The coated wet film is dried in a multi-stage gradient temperature increase to remove solvent and initiate a cross-linking curing reaction; S6. Curing: Place the dried membrane material at 40-45℃ for 24-48 hours to allow the cross-linking reaction to be fully completed.

[0006] As a further technical solution of the present invention, in step S2, the parameters of the corona treatment are: output power 2.0-2.2kW, frequency 10-14kHz, electrode gap 1-1.5mm, treatment speed 80-100m / min, treatment time 0.6s, and the surface tension of the base film after treatment is 50-55dyn / cm.

[0007] As a further technical solution of the present invention, in step S2, the first plasma treatment adopts low-pressure plasma treatment with the following parameters: vacuum degree 20-50Pa, output power 50-100W, ammonia purity ≥99.99%, gas flow rate 500-800sccm, and treatment time 3-5min.

[0008] As a further technical solution of the present invention, in step S2, the second plasma treatment adopts low-pressure plasma treatment with the following parameters: vacuum degree 50-100Pa, output power 150-200W, carbon tetrafluoride purity ≥99.99%, gas flow rate 700-900sccm, and treatment time 2-2.5min.

[0009] As a further technical solution of the present invention, in step S3, the colored coating comprises the following components by weight percentage: 30-40% epoxy resin, 10-20% hydroxyl acrylic resin, 3-5% polyurea resin, 2-5% modified carbon black pigment, 1-3% crosslinking agent, 0.1-0.5% 2-ethyl-4-methylimidazole, 0.1-0.3% defoamer, and the balance being solvent.

[0010] As a further technical solution of the present invention, the modified carbon black pigment is prepared by dispersing carbon black in 10 times its volume of 95% ethanol, adding 1-2% of an aminosilane coupling agent by weight of carbon black, stirring at 60°C for 2 hours, centrifuging and drying to obtain the modified carbon black pigment. The aminosilane coupling agent is selected from any one of (3-aminopropyl)trimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

[0011] As a further technical solution of the present invention, the hydroxyl acrylic resin is selected from BASF Joncryl 587 hydroxyl acrylic resin with a hydroxyl value of 92 and a molecular weight of 7500-10000, the epoxy resin is bisphenol A type epoxy resin with an epoxy equivalent of 700-900, and the polyurea resin has a number average molecular weight of 2000-5000 g / mol.

[0012] As a further technical solution of the present invention, the crosslinking agent is a blocked isocyanate, which is synthesized by isophorone diisocyanate and butanone oxime, the solvent is a mixture of propylene glycol methyl ether and ethyl acetate in a 1:1 ratio, and the defoamer is a non-silicone defoamer.

[0013] As a further technical solution of the present invention, in step S5, the coated base film is subjected to gradient drying through a five-zone continuous drying tunnel. The drying temperatures of each zone of the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃, Zone 3: 160℃, Zone 4: 155℃, Zone 5: 120℃. The drying time of each zone is 9s, and the length of each drying tunnel is 15m. After drying, the film is cooled to room temperature.

[0014] The beneficial effects of this invention are as follows: the base film is first treated with corona to increase surface roughness and oxygen-containing groups, and then amino and fluorine-containing groups are introduced through two plasma treatments, which fully react with the resin in the coating to increase the bonding force between the base film layer and the colored coating, thereby preventing coating peeling. The epoxy resin, hydroxyl acrylic resin and polyurea resin in the colored coating interweave to form a network structure, which reacts with hydroxyl groups in conjunction with a blocked isocyanate crosslinking agent, and the addition of 2-ethyl-4-methylimidazolium catalyst to catalyze the ring-opening of epoxy groups in the epoxy resin and crosslinking with amino and hydroxyl groups to form a dense film layer, effectively increasing the wear resistance of the coating. After treatment with aminosilane, the modified carbon black can be more evenly dispersed in the coating, avoiding uneven color and spots, so that the film material presents a uniform color. At the same time, the dense film layer can also improve the gloss and achieve a high-gloss effect. The multi-stage gradient drying and subsequent curing steps can fully evaporate the solvent and complete the crosslinking reaction, avoiding bubbles and cracks in the film material, further ensuring the stability of the film material. 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 the 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 manufacturing process for a high-fastness, colored, high-gloss composite film packaging material includes the following steps: S1. Base film preparation and pretreatment: Select polyester PET or polypropylene PP film as the base film, and perform static electricity removal and ultrasonic cleaning on it. S2. Surface activation treatment: The pretreated base film is subjected to corona treatment, first plasma treatment and second plasma treatment in sequence; the first plasma treatment uses ammonia as the working gas to introduce amino groups on the surface of the base film; the second plasma treatment uses carbon tetrafluoride as the working gas to introduce fluorine-containing groups on the surface of the base film. S3. Preparation of colored coating: Epoxy resin, hydroxyl acrylic resin and polyurea resin are dissolved in a solvent and stirred at a high speed of 1000-1500 rpm for 30 min. Modified carbon black and defoamer are added and stirring is continued for 1 h. Finally, crosslinking agent and 2-ethyl-4-methylimidazole are added and stirred at a high speed for 5 min. Impurities are removed by passing the mixture through a 5 μm filter screen. The viscosity of the coating is controlled at 100-300 cP to obtain the colored coating. S4. Coating: The colored coating obtained in step S3 is applied to the surface of the treated base film using a reverse roller coating machine. The coating speed is 50-100m / min and the wet film thickness is 10-20μm. S5. Gradient drying and curing: The coated wet film is dried in a multi-stage gradient temperature increase to remove solvent and initiate a cross-linking curing reaction; S6. Curing: Place the dried membrane material at 40-45℃ for 24-48 hours to allow the cross-linking reaction to be fully completed.

[0017] In the base film preparation and surface activation stages, this invention ensures the cleanliness of the base film through static electricity removal and ultrasonic cleaning. Subsequently, corona treatment combined with two plasma treatments sequentially introduces oxygen-containing, amino, and fluorine-containing groups. This three-stage surface modification of the base film not only increases its roughness but also provides active sites for subsequent coatings. Chemical bonding significantly enhances the adhesion between the coating and the base film, effectively preventing coating peeling and wear, and extending the service life of the packaging material. In the colored coating preparation process, the synergistic effect of epoxy resin, hydroxyl acrylic resin, and polyurea resin, along with modified carbon black and crosslinking agents, forms a dense crosslinked network structure. The modified carbon black, treated with aminosilane, improves its dispersibility, ensuring uniform color without spots. Furthermore, under the promotion of the catalyst 2-ethyl-4-methylimidazolium, various resins undergo ring-opening and crosslinking reactions, forming a stable chemical crosslinked network, thereby endowing the coating with high wear resistance and mechanical strength. In the coating and gradient drying / curing stages, the wet film thickness is precisely controlled using a reverse roller coater, combined with multi-stage heating and drying to gradually remove solvents and initiate cross-linking reactions. The gradient heating method avoids bubbles or cracking caused by sudden temperature changes, ensuring the uniformity and integrity of the coating structure. Subsequent curing steps are carried out at low temperatures to fully complete the cross-linking reaction, further stabilizing the film's chemical structure and improving overall durability and environmental adaptability. Overall, this invention, through comprehensive optimization of surface treatment, coating formulation, and curing process, produces a composite film that not only possesses high strength and high gloss but also meets the dual requirements of aesthetics and functionality for packaging materials in fields such as cigarette packaging.

[0018] As one of the preferred embodiments of the present invention, in step S2, the parameters of the corona treatment are: output power 2.0-2.2kW, frequency 10-14kHz, electrode gap 1-1.5mm, treatment speed 80-100m / min, treatment time 0.6s, and the surface tension of the base film after treatment is 50-55dyn / cm.

[0019] The purpose of corona treatment is to ionize air using a high-frequency, high-voltage electric field to generate plasma. The high energy of the plasma alters the surface state of the base film. The output power is controlled at 2.0-2.2kW and the frequency at 10-14kHz to stabilize the electric field. This ensures that the plasma has sufficient energy to break the molecular bonds on the base film surface without causing thermal deformation of the film due to excessive power. The electrode gap is 1-1.5mm to keep the electric field strength within a reasonable range, allowing the plasma to fully contact the base film surface while preventing damage to the electrodes and film due to an excessively small gap. The processing speed of 80-100m / min and the processing time of 0.6s are matched to ensure that the base film surface has sufficient time to complete molecular reconstruction and to adapt to the continuous production rhythm.

[0020] After corona treatment, the surface tension of the base film is 50-55 dyn / cm, indicating that not only has a micro-rough structure been formed on the surface, but also oxygen-containing active groups such as hydroxyl and carboxyl groups have been introduced. These changes can enhance the interaction with resin molecules in the coating, improve the adhesion of subsequent coatings, and avoid peeling problems.

[0021] As one of the preferred embodiments of the present invention, in step S2, the first plasma treatment adopts low-pressure plasma treatment with the following parameters: vacuum degree 20-50Pa, output power 50-100W, ammonia purity ≥99.99%, gas flow rate 500-800sccm, and treatment time 3-5min.

[0022] The first plasma treatment uses ammonia as a medium, which can directionally introduce amino groups (mainly primary amines) onto the substrate surface. The low vacuum of 20-50 Pa can significantly reduce interference from air impurities, allowing ammonia molecules to surround the substrate more densely, creating a pure environment for plasma generation. The output power of 50-100 W excites the ammonia to ionize, generating nitrogen-containing active particles without damaging the substrate structure due to excessive energy. High-purity ammonia can avoid the generation of ineffective groups by impurity gases, ensuring that the active particles are mainly amino groups. The gas flow rate of 500-800 sccm can maintain the stable existence of the plasma, while allowing the amino active particles to uniformly cover the substrate surface.

[0023] The amino groups introduced through the first plasma treatment will subsequently undergo a ring-opening reaction with the epoxy resin in the coating under the action of a catalyst, forming a stable chemical crosslink. This bond is tighter than simple physical adhesion, and combined with the rough surface formed by corona treatment, it further enhances the bonding strength between the coating and the base film, reducing the risk of peeling.

[0024] As one of the preferred embodiments of the present invention, in step S2, the second plasma treatment adopts low-pressure plasma treatment with the following parameters: vacuum degree 50-100Pa, output power 150-200W, carbon tetrafluoride purity ≥99.99%, gas flow rate 700-900sccm, and treatment time 2-2.5min.

[0025] In the second plasma treatment step, carbon tetrafluoride is used as the working gas. Utilizing the high reactivity of the low-pressure plasma environment, fluorination modification is performed on the substrate film surface, introducing fluorine-containing groups. When the system vacuum is maintained at 50-100 Pa, the gas molecules within the reaction chamber are relatively rarefied. Under 150-200 W of radio frequency power excitation, the carbon tetrafluoride gas is ionized, forming a plasma containing electrons, ions, free radicals, and excited-state molecules. The generated highly reactive fluorocarbon free radicals, such as ·CF3 and ·CF2, can modify the substrate film surface.

[0026] The aforementioned highly reactive fluorocarbon free radicals collide with the polymer molecular chains of the base film, grafting fluorine-containing groups onto the molecular chains through two main pathways: hydrogen abstraction reaction and direct bonding. Specifically, the fluorocarbon free radicals attack and abstract hydrogen atoms from the polyester or polypropylene molecular chains to generate fluorinated hydrocarbon structures. At the same time, they can also directly combine with active sites (such as free radicals) generated by the first plasma treatment, thereby stably introducing fluorine-containing functional groups such as trifluoromethyl and difluoromethylene onto the surface of the base film.

[0027] As one of the preferred embodiments of the present invention, in step S3, the colored coating comprises the following components by weight percentage: 30-40% epoxy resin, 10-20% hydroxyl acrylic resin, 3-5% polyurea resin, 2-5% modified carbon black pigment, 1-3% crosslinking agent, 0.1-0.5% 2-ethyl-4-methylimidazole, 0.1-0.3% defoamer, and the balance being solvent.

[0028] Specifically, the preferred proportions of the colored coating components are: 35% epoxy resin, 15% hydroxyl acrylic resin, 4% polyurea resin, 3% modified carbon black pigment, 2% crosslinking agent, 0.3% 2-ethyl-4-methylimidazole, 0.2% defoamer, and the remainder is solvent.

[0029] In the aforementioned colored coatings, epoxy resin and hydroxyl acrylic resin serve as the main film-forming substances, providing the coating's skeletal structure, good adhesion, and chemical resistance. The numerous hydroxyl groups on the hydroxyl acrylic resin molecular chain provide reaction sites for subsequent crosslinking reactions, while polyurea resin, with its highly polar urea bonds, constructs a hydrogen bond network in the system, enhancing the cohesive strength, toughness, and wear resistance of the colored coating.

[0030] The modified carbon black pigment surface, with amino groups grafted onto the surface of aminosilane, can chemically react with the epoxy groups of the epoxy resin, transforming the pigment particles from physical doping to chemical bonding, thereby fixing them within the resin network. This solves the problems of carbon black's easy agglomeration and poor dispersion stability, ensuring uniform color and no spots, and avoiding performance degradation caused by pigment shedding.

[0031] The crosslinking agent (blocked isocyanate) and the catalyst 2-ethyl-4-methylimidazolium are the main components for forming a dense network. During the drying and curing stage, the crosslinking agent is activated, and its isocyanate groups undergo a polyurethane reaction with the hydroxyl groups of the hydroxyl acrylic resin. At the same time, the catalyst promotes the ring opening of the epoxy groups, which crosslink with the amino groups on the modified carbon black surface, the amino groups introduced on the substrate surface during the first plasma treatment, and the hydroxyl groups of the hydroxyl acrylic resin, respectively, forming a chemically crosslinked network structure. The urea bonds (-NH-CO-NH-) in the polyurea resin molecular chain are good hydrogen bond donors and acceptors, and can spontaneously form a dense hydrogen bond network in the system. Meanwhile, the hydroxyl groups of the hydroxyl acrylic resin itself, and the fluorinated groups (such as -CF2H) introduced on the substrate surface after the second plasma treatment, have extremely high electronegativity and can form hydrogen bonds with adjacent NH or OH groups, forming a physical crosslinked network composed of hydrogen bonds. The above-mentioned hydrogen bond crosslinking and chemical crosslinking work together. Hydrogen bond networks provide rapid initial curing and good toughness, while chemical crosslinking provides the coating with ultimate durability and wear resistance. The two levels of crosslinking structures work together to achieve high adhesion and high wear resistance of the coating on the base film.

[0032] As one of the preferred embodiments of the present invention, the modified carbon black pigment is prepared by dispersing carbon black in 10 times its volume of 95% ethanol, adding 1-2% of an aminosilane coupling agent by weight of carbon black, stirring at 60°C for 2 hours, centrifuging and drying to obtain the modified carbon black pigment. The aminosilane coupling agent is selected from any one of (3-aminopropyl)trimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

[0033] Specifically, the preferred aminosilane coupling agent is 3-(2-aminoethylamino)propyltrimethoxysilane.

[0034] Carbon black was dispersed in 95% ethanol. Ethanol, as a medium, helped to break up the carbon black aggregates and wet their surface. An aminosilane coupling agent was then added. Its molecular structure consists of a methoxysilane at one end that can bind to inorganic substances and an organic long chain containing an amino group at the other end. Under heating and stirring conditions at 60°C, the methoxy group of the coupling agent molecule first hydrolyzes to generate active silanol groups. These silanol groups undergo a dehydration condensation reaction with active sites such as hydroxyl groups on the carbon black particle surface, forming strong Si-OC covalent bonds, thus binding the coupling agent to the carbon black surface. After modification, an amino-rich organic molecular layer was successfully grafted onto the carbon black particle surface. In subsequent coating processing, the amino groups on the modified carbon black surface can undergo ring-opening reactions with the epoxy groups of epoxy resin to form chemical bonds, thereby greatly improving the compatibility and adhesion between the pigment and the resin matrix.

[0035] As one of the preferred embodiments of the present invention, the hydroxyl acrylic resin is selected from BASF Joncryl 587 hydroxyl acrylic resin with a hydroxyl value of 92 and a molecular weight of 7500-10000, the epoxy resin is bisphenol A type epoxy resin with an epoxy equivalent of 700-900, and the polyurea resin has a number average molecular weight of 2000-5000 g / mol.

[0036] The selected BASF Joncryl 587 hydroxyl acrylic resin, with a hydroxyl value of 92, ensures that the resin molecular chain has sufficient reaction sites to fully react with the subsequently added isocyanate crosslinking agent, forming a polyurethane crosslinking network. Simultaneously, its molecular weight of 7500-10000 endows the resin with good film-forming and leveling properties. The bisphenol A epoxy resin, with an epoxy equivalent of 700-900, can fully react with the amino groups on the base film surface and the hydroxyl groups in the coating to form stable chemical crosslinks, without causing excessive brittleness after coating curing due to excessive epoxy groups. The polyurea resin, with a number average molecular weight of 2000-5000, has a moderate molecular chain length, allowing it to interweave well within the molecular networks of the epoxy and acrylic resins. Its urea bonds can also form hydrogen bonds, further densifying the coating structure.

[0037] In one of the preferred embodiments of the present invention, the crosslinking agent is a blocked isocyanate synthesized by isophorone diisocyanate and butanone oxime, the solvent is a mixture of propylene glycol methyl ether and ethyl acetate in a 1:1 ratio, and the defoamer is a non-silicone defoamer.

[0038] Blocked isocyanates are synthesized from isophorone diisocyanate and methyl ethyl ketone oxime. At room temperature, methyl ethyl ketone oxime blocks the isocyanate groups, preventing premature cross-linking failure during coating storage. However, in the high-temperature environment of gradient drying, the blocker deblocks and releases the isocyanate, which can quickly react with the hydroxyl groups of hydroxyl acrylic resin to form stable polyurethane bonds, improving the cross-linking density and compactness of the coating. The solvent, a 1:1 mixture of propylene glycol methyl ether and ethyl acetate, has complementary polarity and evaporation rates. It can fully dissolve all components such as epoxy resin and polyurea resin, keeping the coating uniform and stable and preventing precipitation and stratification, while also gradually evaporating after coating. During gradient drying, the mixed solvent will not produce bubbles or pinholes due to excessively rapid evaporation, nor will it affect the curing progress due to excessively slow evaporation, ensuring a smooth coating film. Non-silicone defoamers should be selected, specifically the Kedigo 920 model. Silicone defoamers are prone to leaving residues that affect the coating gloss, while non-silicone defoamers can effectively eliminate bubbles generated during paint mixing and application, allowing the coating to maintain a smooth and flat appearance, as well as good adhesion and wear resistance.

[0039] As one of the preferred embodiments of the present invention, in step S5, the coated base film is subjected to gradient drying through a five-zone continuous drying tunnel. The drying temperatures of each zone in the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃, Zone 3: 160℃, Zone 4: 155℃, Zone 5: 120℃. The drying time of each zone is 9s, and the length of each drying tunnel is 15m. After drying, the film is cooled to room temperature.

[0040] Specifically, the first zone, drying at a low temperature of 70°C, primarily allows the mixed solvent to evaporate slowly, preventing rapid boiling and bubble formation. The second zone, heated to 135°C, further evaporates residual solvent and, more importantly, de-blocks the isocyanate's blocking agent, releasing isocyanate groups that begin a polyurethane reaction with the primary hydroxyl groups of the hydroxyl acrylic resin, initiating the crosslinking process. Simultaneously, this temperature also allows for moderate movement of the resin molecular chains, promoting interpenetration between different resins.

[0041] The third drying zone is 160℃, and the fourth zone is 155℃. This process accelerates the ring-opening reaction between the 2-ethyl-4-methylimidazolium and the epoxy resin with amino and hydroxyl groups, allowing the resin system to form a dense network structure. This significantly improves the coating's wear resistance and adhesion. The high temperature also thoroughly removes residual trace solvents, preventing pinholes and cracking during subsequent curing or use. The fifth zone cools down to 120℃ for 1 minute, gradually reducing the temperature to allow the coating to cool slowly and prevent sudden cooling that could cause internal stress, leading to brittleness or peeling from the base film. Finally, cooling to room temperature allows the coating structure to solidify and maintain a smooth and even surface.

[0042] The present invention will be further described below through examples and comparative examples. Example 1 S1. Place the polyester PET film (12μm thick) in an ultrasonic cleaner for ultrasonic cleaning, then dry it at 50℃, and then perform an antistatic operation on an antistatic device. S2. Corona treatment: Output power 2.1kW, frequency 12kHz, electrode gap 1.2mm, treatment speed 90m / min, treatment time 0.6s; First plasma treatment: Vacuum degree 30Pa, output power 75W, ammonia purity 99.99%, gas flow rate 600sccm, treatment time 4min; Second plasma treatment: Vacuum degree 75Pa, output power 175W, carbon tetrafluoride purity 99.99%, gas flow rate 800sccm, treatment time 2.25min; S3. Preparation of colored coating (by weight percentage): epoxy resin (bisphenol A type, epoxy equivalent 800) 35%, hydroxyl acrylic resin (BASF Joncryl 587, hydroxyl value 92) 15%, polyurea resin (number average molecular weight 3500 g / mol) 4%, modified carbon black pigment (modified with 3-(2-aminoethylamino)propyltrimethoxysilane) 3%, crosslinking agent (blocked isocyanate) 2%, 2-ethyl-4-methylimidazolium 0.3%, defoamer (non-silicone defoamer, DIG 920) 0.2%, solvent (propylene glycol methyl ether: ethyl acetate = 1:1) 40.5%; coating is carried out using a reverse roller coater at a coating speed of 75 m / min and a wet film thickness of 15 μm. S4. Gradient drying and curing: The drying temperatures of each zone in the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃; Zone 3: 160℃, Zone 4: 155℃; Zone 5: 120℃; The drying time for each zone is 9 seconds, and then the temperature is cooled to room temperature. S5. Curing: Place at 42.5℃ for 36 hours.

[0043] Example 2 S1. Place the polypropylene (PP) film (15μm thick) in an ultrasonic cleaner for ultrasonic cleaning, then dry it at 50℃, and then perform an antistatic operation on an antistatic device. S2. Corona treatment: Output power 2.0kW, frequency 10kHz, electrode gap 1mm, treatment speed 90m / min, treatment time 0.6s; First plasma treatment: Vacuum degree 20Pa, output power 50W, ammonia purity 99.99%, gas flow rate 500sccm, treatment time 3min; Second plasma treatment: Vacuum degree 50Pa, output power 150W, carbon tetrafluoride purity 99.99%, gas flow rate 700sccm, treatment time 2min; S3. Preparation of colored coating (by weight percentage): epoxy resin (bisphenol A type, epoxy equivalent 700) 30%, hydroxyl acrylic resin (BASF Joncryl 587, hydroxyl value 92) 10%, polyurea resin (number average molecular weight 2000 g / mol) 3%, modified carbon black pigment (modified with 3-(2-aminoethylamino)propyltrimethoxysilane) 2%, crosslinking agent (blocked isocyanate) 1%, 2-ethyl-4-methylimidazolium 0.1%, defoamer (non-silicone defoamer, DIG 920) 0.1%, solvent (propylene glycol methyl ether: ethyl acetate = 1:1) 53.8%; coating is performed using a reverse roller coater at a coating speed of 50 m / min and a wet film thickness of 10 μm. S4. Gradient drying and curing: The drying temperatures of each zone in the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃; Zone 3: 160℃, Zone 4: 155℃; Zone 5: 120℃; The drying time for each zone is 9 seconds, and then the temperature is cooled to room temperature. S5. Curing: Place at 40℃ for 24 hours.

[0044] Example 3 S1. Place the polyester PET film (12μm thick) in an ultrasonic cleaner for ultrasonic cleaning, then dry it at 50℃, and then perform an antistatic operation on an antistatic device. S2. Corona treatment: Output power 2.2kW, frequency 14kHz, electrode gap 1.5mm, processing speed 90m / min, processing time 0.6s; First plasma treatment: Vacuum degree 50Pa, output power 100W, ammonia purity 99.99%, gas flow rate 800sccm, processing time 5min; Second plasma treatment: Vacuum degree 100Pa, output power 200W, carbon tetrafluoride purity 99.99%, gas flow rate 900sccm, processing time 2.5min; S3. Preparation of colored coating (by weight percentage): epoxy resin (bisphenol A type, epoxy equivalent 900) 40%, hydroxyl acrylic resin (BASF Joncryl 587, hydroxyl value 92) 20%, polyurea resin (number average molecular weight 5000 g / mol) 5%, modified carbon black pigment (modified with 3-(2-aminoethylamino)propyltrimethoxysilane) 5%, crosslinking agent (blocked isocyanate) 3%, 2-ethyl-4-methylimidazolium 0.5%, defoamer (non-silicone defoamer, DIG 920) 0.3%, solvent (propylene glycol methyl ether: ethyl acetate = 1:1) 26.2%; coating is performed using a reverse roller coater at a coating speed of 100 m / min and a wet film thickness of 20 μm. S4. Gradient drying and curing: The drying temperatures of each zone in the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃; Zone 3: 160℃, Zone 4: 155℃; Zone 5: 120℃; The drying time for each zone is 9 seconds, and then the temperature is cooled to room temperature. S5. Curing: Place at 45℃ for 48 hours.

[0045] Example 4 S1. Place the polypropylene (PP) film (15μm thick) in an ultrasonic cleaner for ultrasonic cleaning, then dry it at 50℃, and then perform an antistatic operation on an antistatic device. S2. Corona treatment: Output power 2.1kW, frequency 12kHz, electrode gap 1.2mm, treatment speed 90m / min, treatment time 0.6s; First plasma treatment: Vacuum degree 40Pa, output power 80W, ammonia purity 99.99%, gas flow rate 700sccm, treatment time 4min; Second plasma treatment: Vacuum degree 80Pa, output power 180W, carbon tetrafluoride purity 99.99%, gas flow rate 850sccm, treatment time 2.25min; S3. Preparation of colored coating (weight percentage): epoxy resin (bisphenol A type, epoxy equivalent 850) 38%, hydroxyl acrylic resin (BASF Joncryl 587, hydroxyl value 92) 18%, polyurea resin (number average molecular weight 4000 g / mol) 4.5%, modified carbon black pigment (modified with 3-(2-aminoethylamino)propyltrimethoxysilane) 4%, crosslinking agent (blocked isocyanate) 2.5%, 2-ethyl-4-methylimidazolium 0.4%, defoamer (non-silicone defoamer, DIG 920) 0.25%, solvent (propylene glycol methyl ether: ethyl acetate = 1:1) 32.35%; coating is carried out using a reverse roller coater at a coating speed of 80 m / min and a wet film thickness of 18 μm. S4. Gradient drying and curing: The drying temperatures of each zone in the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃; Zone 3: 160℃, Zone 4: 155℃; Zone 5: 120℃; The drying time for each zone is 9 seconds, and then the temperature is cooled to room temperature. S5. Curing: Place at 43℃ for 40 hours.

[0046] Example 5 S1. Place the polyester PET film (12μm thick) in an ultrasonic cleaner for ultrasonic cleaning, then dry it at 50℃, and then perform an antistatic operation on an antistatic device. S2. Corona treatment: Output power 2.0kW, frequency 13kHz, electrode gap 1.3mm, treatment speed 90m / min, treatment time 0.6s; First plasma treatment: Vacuum degree 25Pa, output power 60W, ammonia purity 99.99%, gas flow rate 550sccm, treatment time 3.5min; Second plasma treatment: Vacuum degree 60Pa, output power 160W, carbon tetrafluoride purity 99.99%, gas flow rate 750sccm, treatment time 2.1min; S3. Preparation of colored coating (weight percentage): epoxy resin (bisphenol A type, epoxy equivalent 750) 32%, hydroxyl acrylic resin (BASF Joncryl 587, hydroxyl value 92) 12%, polyurea resin (number average molecular weight 3000 g / mol) 3.5%, modified carbon black pigment (modified with 3-(2-aminoethylamino)propyltrimethoxysilane) 2.5%, crosslinking agent (blocked isocyanate) 1.5%, 2-ethyl-4-methylimidazolium 0.2%, defoamer (non-silicone defoamer, DIG 920) 0.15%, solvent (propylene glycol methyl ether: ethyl acetate = 1:1) 48.15%; coating is carried out using a reverse roller coater at a coating speed of 60 m / min and a wet film thickness of 12 μm. S4. Gradient drying and curing: The drying temperatures of each zone in the five-zone drying tunnel are as follows: Zone 1: 70℃, Zone 2: 135℃; Zone 3: 160℃, Zone 4: 155℃; Zone 5: 120℃; The drying time for each zone is 9 seconds, and then the temperature is cooled to room temperature. S5. Curing: Place at 41℃ for 30 hours.

[0047] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the surface activation treatment only involves static electricity removal and ultrasonic cleaning, omitting the corona treatment and two plasma treatments. The remaining steps (base film, coating preparation, coating, drying and curing, and aging) are completely consistent with Example 1.

[0048] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in the preparation of the colored coating, ordinary carbon black pigment that has not been modified by 3-(2-aminoethylamino)propyltrimethoxysilane is used instead of modified carbon black pigment, while the remaining steps (base film, surface activation treatment, coating, drying and curing, aging) are completely consistent with Example 1.

[0049] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the gradient drying and curing steps are changed to direct drying at 160°C for 45 seconds, replacing the original five-stage gradient drying process. The remaining steps (base film, surface activation treatment, coating preparation, coating, curing) are completely consistent with Example 1.

[0050] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the S5 curing step is omitted, and the performance test is carried out directly after gradient drying and curing and cooling to room temperature. The remaining steps (base film, surface activation treatment, coating preparation, coating, drying and curing) are completely consistent with Example 1.

[0051] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the first ammonia plasma treatment is omitted in the surface activation treatment, and only the corona treatment and the second carbon tetrafluoride plasma treatment are retained. The parameters of the retained treatment steps are the same as those in Example 1, and the remaining steps (base film, coating preparation, coating, drying and curing, and ripening) are completely the same as those in Example 1.

[0052] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the second carbon tetrafluoride plasma treatment is omitted in the surface activation treatment, and only the corona treatment and the first ammonia plasma treatment are retained. The parameters of the retained treatment steps are the same as those in Example 1. The remaining steps (base film, coating preparation, coating, drying and curing, and aging) are completely the same as those in Example 1.

[0053] Performance testing The gloss of the coating layer was tested in accordance with the standard GB / T9754-2007 Determination of 20°, 60° and 85° specular gloss of paint films without metallic pigments.

[0054] Refer to the standard GB / T13217.7-2023 "Test Method for Adhesion of Ink" to test the adhesion strength of the coating layer (a total of six levels from 0 to 5, with 0 being the best).

[0055] A friction fastness tester was used to rub the sample under a load of 200g, observe the peeling of the coating layer, and record the maximum number of rubbing cycles.

[0056] The test results are shown in the table below:

[0057] Based on the comparative data of the examples and comparative examples, it can be seen that Examples 1-5 all exhibit excellent gloss (82-88 GU), high adhesion level (0-2 grade), and excellent abrasion resistance (155-185 cycles), proving the reliability and repeatability of the process of the present invention. Comparative Example 1, after omitting all surface treatment, showed a sharp drop in adhesion to grade 5 and abrasion resistance of only 40 cycles, indicating performance degradation. This demonstrates that surface modification of the base film is crucial for establishing a strong interfacial bond. Further analysis revealed that the performance of Comparative Example 5 (lacking amino groups) and Comparative Example 6 (lacking fluorine-containing groups) was significantly worse than that of Example 1. This indicates that amino groups achieved chemical bonding with the epoxy groups of the coating, while fluorine-containing groups enhanced the interfacial forces by forming a strong hydrogen bond network. The synergistic effect of both significantly improved adhesion and abrasion resistance. Comparative Example 2 used unmodified carbon black, which resulted in a decrease in gloss, adhesion, and abrasion resistance. This indicates that the amination treatment of the carbon black surface is crucial for improving its dispersibility and chemical bonding with the resin, and can effectively prevent pigment agglomeration and detachment. Comparative Example 3 used a one-step high-temperature drying process, which resulted in defects in the coating and a decrease in performance due to solvent evaporation and excessively rapid reaction. Comparative Example 4 omitted the curing step, which resulted in insufficient abrasion resistance due to inadequate crosslinking reaction. This demonstrates the importance of gradual heating and sufficient curing for the formation of a complete and dense crosslinked network.

[0058] 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 manufacturing process for a high-fastness, colored, high-gloss composite film packaging material, characterized in that, Includes the following steps: S1. Base film preparation and pretreatment: Select polyester PET or polypropylene PP film as the base film, and perform static electricity removal and ultrasonic cleaning on it. S2. Surface activation treatment: The pretreated base film is subjected to corona treatment, first plasma treatment and second plasma treatment in sequence; the first plasma treatment uses ammonia as the working gas to introduce amino groups on the surface of the base film. The second plasma treatment uses carbon tetrafluoride as the working gas to introduce fluorine-containing groups on the surface of the base film. S3. Preparation of colored coating: Epoxy resin, hydroxyl acrylic resin and polyurea resin are dissolved in a solvent and stirred at a high speed of 1000-1500 rpm for 30 min. Modified carbon black and defoamer are added and stirring is continued for 1 h. Finally, crosslinking agent and 2-ethyl-4-methylimidazole are added and stirred at a high speed for 5 min. Impurities are removed by passing the mixture through a 5 μm filter screen. The viscosity of the coating is controlled at 100-300 cP to obtain the colored coating. S4. Coating: The colored coating obtained in step S3 is applied to the surface of the treated base film using a reverse roller coating machine. The coating speed is 50-100m / min and the wet film thickness is 10-20μm. S5. Gradient drying and curing: The coated wet film is dried in a multi-stage gradient temperature increase to remove solvent and initiate a cross-linking curing reaction; S6. Curing: Place the dried membrane material at 40-45℃ for 24-48 hours to allow the cross-linking reaction to be fully completed.

2. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 1, characterized in that, In step S2, the parameters of the corona treatment are: output power 2.0-2.2kW, frequency 10-14kHz, electrode gap 1-1.5mm, treatment speed 80-100m / min, treatment time 0.6s, and the surface tension of the base film after treatment is 50-55dyn / cm.

3. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 1, characterized in that, In step S2, the first plasma treatment uses low-pressure plasma treatment with the following parameters: vacuum degree 20-50 Pa, output power 50-100 W, ammonia purity ≥99.99%, gas flow rate 500-800 sccm, and treatment time 3-5 min.

4. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 1, characterized in that, In step S2, the second plasma treatment is performed using low-pressure plasma treatment with the following parameters: vacuum degree 50-100Pa, output power 150-200W, carbon tetrafluoride purity ≥99.99%, gas flow rate 700-900sccm, and treatment time 2-2.5min.

5. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 1, characterized in that, In step S3, the colored coating comprises the following components by weight percentage: 30-40% epoxy resin, 10-20% hydroxyl acrylic resin, 3-5% polyurea resin, 2-5% modified carbon black pigment, 1-3% crosslinking agent, 0.1-0.5% 2-ethyl-4-methylimidazole, 0.1-0.3% defoamer, and the balance being solvent.

6. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 5, characterized in that, The modified carbon black pigment is prepared by dispersing carbon black in 10 times its volume of 95% ethanol, adding 1-2% of an aminosilane coupling agent by weight of carbon black, stirring at 60°C for 2 hours, centrifuging and drying to obtain the modified carbon black pigment. The aminosilane coupling agent is selected from any one of (3-aminopropyl)trimethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

7. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 5, characterized in that, The hydroxyl acrylic resin is selected from BASF Joncryl 587 hydroxyl acrylic resin, with a hydroxyl value of 92 and a molecular weight of 7500-10000. The epoxy resin is a bisphenol A type epoxy resin with an epoxy equivalent of 700-900. The number average molecular weight of the polyurea resin is 2000-5000 g / mol.

8. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 5, characterized in that, The crosslinking agent is a blocked isocyanate synthesized from isophorone diisocyanate and butanone oxime, the solvent is a mixture of propylene glycol methyl ether and ethyl acetate in a 1:1 ratio, and the defoamer is a non-silicone defoamer.

9. The manufacturing process of a high-fastness colored high-gloss composite film packaging material according to claim 1, characterized in that, In step S5, the coated base film is subjected to gradient drying through a five-zone drying tunnel. The drying temperatures of each zone are as follows: Zone 1: 70℃, Zone 2: 135℃, Zone 3: 160℃, Zone 4: 155℃, Zone 5: 120℃. The drying time for each zone is 9 seconds, and the length of each drying tunnel is 15m. After drying, the film is cooled to room temperature.

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