A UV-cured laser anti-counterfeiting color layer coating and a preparation method thereof

Abstract

The present application provides a kind of UV solidification laser anti-counterfeiting color layer paint and preparation method thereof.The paint includes the following weight parts of raw materials: polyurethane acrylate resin 50-60 parts, epoxy acrylate resin 15-25 parts, double maleimide and furan-based polyurethane prepolymer 5-10 parts, N,N';-bis (4-aminophenyl) terephthalamide 2-5 parts, long afterglow luminescent material 3-8 parts, active diluent 25-35 parts, photoinitiator 2-5 parts, leveling agent 0.5-2 parts.The laser anti-counterfeiting color layer paint has good hot stamping peeling strength, mechanical properties and weather resistance, good anti-counterfeiting effect, can be UV solidified, hot stamping effect is good, and the preparation method of paint is simple and easy to control, process is stable, is conducive to industrial production.

Description

Technical Field

[0001] This invention relates to the field of electroplated aluminum technology, specifically to a UV-curable laser anti-counterfeiting color coating and its preparation method. Background Technology

[0002] Laser anti-counterfeiting electroplated aluminum foil, also known as laser hot stamping foil, is a functional film material that integrates anti-counterfeiting and decorative functions. It is widely used in high-end packaging for tobacco, alcohol, cosmetics, pharmaceuticals, and food. A typical laser anti-counterfeiting electroplated aluminum foil consists of a base film layer, a release layer, a color layer (information layer), an aluminum plating layer, and a hot melt adhesive layer, layered sequentially. The color layer is the core functional layer carrying the laser holographic pattern, and its performance significantly impacts the clarity of the laser effect, the adaptability of hot stamping, and the overall quality of the product. Currently, most laser color layer coatings are solvent-based thermosetting; water-based coatings and UV-cured coating technologies are not yet widely used in this field.

[0003] In addition, current laser color coatings on the market generally suffer from the following problems: poor hot stamping peel strength, easily leading to delamination and cracking during high-temperature lamination, die-cutting, and other processing; poor environmental resistance, easily yellowing and aging when exposed to light and humidity for a long time, resulting in blurred anti-counterfeiting information; and insufficient anti-counterfeiting identification. UV curing technology, on the other hand, is a mature technology in the field of thin-film coatings, combining weather resistance and flexibility with extremely fast curing speed, low VOC content, and greater environmental friendliness. Therefore, developing a UV-curable laser color coating for electroplated aluminum information layers that combines good anti-counterfeiting identification, hot stamping peel strength, and environmental resistance has become a pressing technical problem for the industry. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing a UV-curable laser anti-counterfeiting color layer coating for use as an information layer on electroplated aluminum. The coating has good hot stamping peel strength, mechanical properties, and weather resistance, and has good anti-counterfeiting effect. It can be UV cured and has a good hot stamping effect. Furthermore, the preparation method of this coating is simple and easy to control, the process is stable, and it is conducive to industrial production.

[0005] The objective of this invention is achieved through the following technical solution: a UV-curable laser anti-counterfeiting color layer coating, comprising the following raw materials in parts by weight: 50-60 parts of polyurethane acrylate resin, 15-25 parts of epoxy acrylate resin, 5-10 parts of bismaleimide and furanyl polyurethane prepolymer, 2-5 parts of N,N'-bis(4-aminophenyl)terephthalamide, 3-8 parts of long afterglow luminescent material, 25-35 parts of reactive diluent, 2-5 parts of photoinitiator, and 0.5-2 parts of leveling agent.

[0006] Furthermore, the reactive diluent is at least one selected from trimethylolpropane triacrylate, tripropylene glycol diacrylate, and 1,6-hexanediol diacrylate.

[0007] Furthermore, the photoinitiator is an acylphosphine oxide photoinitiator or a thionium salt cationic photoinitiator.

[0008] Furthermore, the acylphosphine oxide photoinitiator is at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide; the thioonium salt cationic photoinitiator is at least one of triarylthioonium salt and diaryliodonium salt.

[0009] Furthermore, the long afterglow luminescent material is strontium europium dysprosium aluminate, which is an aluminate compound doped with europium and dysprosium rare earth materials. It has high brightness and a significantly longer luminescence time, i.e., a long afterglow time. Adding such a substance helps to improve the anti-counterfeiting effect of the coating.

[0010] Furthermore, the leveling agent is polyether-modified polydimethylsiloxane. Polyether-modified polydimethylsiloxane leveling agents help reduce the surface tension of the coating, improve application flow, avoid defects such as pinholes and orange peel, and ensure that the laser texture can be completely replicated.

[0011] Furthermore, the preparation method of the bismaleimide and furanyl polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol was added to the reaction vessel, the temperature was raised to 75-85℃, isophorone diisocyanate and catalyst were added, and the reaction was carried out for 2-4 hours to obtain isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 1.8-2.2:1. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 55-65℃, add furfurylamine, and stir for 1-3 hours to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide are mixed at a molar ratio of furan group to bismaleimide group of 1:0.5-1 and reacted at 65-75℃ for 4-7h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

[0012] Furthermore, in step (A1), the catalyst is at least one of dibutyltin dilaurate and an organobismuth catalyst.

[0013] This invention combines polyurethane acrylate resin and epoxy acrylate resin in a certain ratio to balance the toughness and rigidity of the coating; and introduces bismaleimide and furan-based polyurethane prepolymer, in which the furan ring in the molecular chain can react with the bismaleimide group to form a network structure with moderate crosslinking density, which is beneficial to improving the high temperature resistance and crack resistance of the coating; the amino group of N,N'-bis(4-aminophenyl)terephthalamide can react with the carboxyl group and isocyanate group in the resin matrix to further increase the crosslinking density.

[0014] This invention also provides a method for preparing a UV-curable laser anti-counterfeiting color layer coating, comprising the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, stir and mix evenly to obtain resin premix; (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat and stir until uniform; (3) Cool the mixture to room temperature, add photoinitiator and long afterglow luminescent material, stir evenly to obtain UV-cured laser anti-counterfeiting color layer coating.

[0015] Furthermore, in step (2), N,N'-bis(4-aminophenyl)terephthalamide and leveling agent are added to the resin premix, the temperature is raised to 55-65°C, and the mixture is stirred until homogeneous.

[0016] The beneficial effects of this invention are as follows: By compounding polyurethane acrylate resin and epoxy acrylate resin, and introducing raw materials such as bismaleimide and furanyl polyurethane prepolymer, N,N'-bis(4-aminophenyl)terephthalamide, long afterglow luminescent material, reactive diluent, and photoinitiator, this invention enables the UV-curable laser anti-counterfeiting color layer coating to possess excellent hot stamping peel strength, mechanical properties, and weather resistance, resulting in good anti-counterfeiting effect, self-healing properties, and UV curing capability with excellent hot stamping effect. The preparation method of the UV-curable laser anti-counterfeiting color layer coating is simple and easy to control, with a stable process, which is conducive to industrial production. Detailed Implementation

[0017] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0018] In some embodiments of the present invention, a UV-curable laser anti-counterfeiting color coating comprises the following raw materials in parts by weight: 50-60 parts of polyurethane acrylate resin, 15-25 parts of epoxy acrylate resin, 5-10 parts of bismaleimide and furanyl polyurethane prepolymer, 2-5 parts of N,N'-bis(4-aminophenyl)terephthalamide, 3-8 parts of long afterglow luminescent material, 25-35 parts of reactive diluent, 2-5 parts of photoinitiator, and 0.5-2 parts of leveling agent.

[0019] In some embodiments of the present invention, the reactive diluent is at least one selected from trimethylolpropane triacrylate (TMPTA), tripropylene glycol diacrylate (TPGDA), and 1,6-hexanediol diacrylate (HDDA).

[0020] In some embodiments of the present invention, the photoinitiator is an acylphosphine oxide photoinitiator and a thionium salt cationic photoinitiator. The acylphosphine oxide photoinitiator is at least one selected from 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; the thionium salt cationic photoinitiator is at least one selected from triarylthionium salt and diaryliodoonium salt.

[0021] In some embodiments of the present invention, the photoinitiator is composed of an acylphosphine oxide photoinitiator and a thionium salt cationic photoinitiator in a mass ratio of 1-4:1.

[0022] In some embodiments of the present invention, the long afterglow luminescent material is europium aluminate dysprosium.

[0023] In some embodiments of the present invention, the leveling agent is polyether-modified polydimethylsiloxane.

[0024] In some embodiments of the present invention, the preparation method of the bismaleimide and furanyl polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol is added to a reaction vessel, heated to 75-85℃, isophorone diisocyanate and catalyst are added, and the reaction is carried out for 2-4 hours to obtain isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 1.8-2.2:1; the amount of catalyst used is 0.02-0.2% of the mass of polycaprolactone diol. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 55-65℃, add furfurylamine, the amount of furfurylamine is calculated according to the NCO:NH2 molar ratio of 1:1; stir the reaction for 1-3 hours to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide are mixed at a molar ratio of furan group to bismaleimide group of 1:0.5-1 and reacted at 65-75℃ for 4-7h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

[0025] In some embodiments of the present invention, in step (A1), the catalyst is at least one of dibutyltin dilaurate and an organobismuth catalyst.

[0026] This invention combines bismaleimide with furanyl polyurethane prepolymer and N,N'-bis(4-aminophenyl)terephthalamide to synergistically introduce Diels-Alder dynamic covalent bonds (DA dynamic covalent bonds) and hydrogen bonds into a UV-curable laser anti-counterfeiting color layer coating system, constructing a dual reversible crosslinking network. At a molding temperature of 80-100℃, the DA bonds undergo a reverse reaction to decrosslink, hydrogen bonds break, and the coating viscosity decreases, facilitating the filling of the grating structure of the nickel plate. At a hot stamping temperature of 150-180℃, the DA bonds decrosslink again, ensuring clean separation of the color layer and the release layer. After cooling, the DA bonds and hydrogen bonds re-recombine to form a stable crosslinking network, giving the UV-curable laser anti-counterfeiting color layer coating layer both low-temperature molding properties, high hot stamping adhesion, and self-healing function.

[0027] In some embodiments of the present invention, a method for preparing a UV-curable laser anti-counterfeiting color layer coating includes the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, and stir and mix them evenly at a speed of 300-500 r / min to obtain resin premix. (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat to 55-65℃, and stir at 500-1000r / min for 10-30min; (3) Cool the mixture to room temperature, add the photoinitiator and long afterglow luminescent material, and stir at 800-1500 r / min for 20-40 min to obtain a UV-curable laser anti-counterfeiting color layer coating. The coating can be molded at 80-90℃ and hot stamped at 150-180℃, and has no surface stickiness after UV curing.

[0028] Example 1

[0029] In this embodiment, a UV-curable laser anti-counterfeiting color layer coating comprises the following raw materials in parts by weight: 55 parts polyurethane acrylate resin, 20 parts epoxy acrylate resin, 8 parts bismaleimide and furanyl polyurethane prepolymer, 3 parts N,N'-bis(4-aminophenyl)terephthalamide, 5 parts long afterglow luminescent material, 30 parts reactive diluent, 3 parts photoinitiator, and 1 part leveling agent. The polyurethane acrylate resin is Kunshan Castel U-CURE 93721. The epoxy acrylate resin is Changxing Resin 621A-80.

[0030] Furthermore, the reactive diluent is composed of trimethylolpropane triacrylate and tripropylene glycol diacrylate in a mass ratio of 2:1.

[0031] Furthermore, the photoinitiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and triarylthionium hexafluoroantimonate in a mass ratio of 3:1.

[0032] Furthermore, the long afterglow luminescent material is selected from ALDRICH Strontium Europium Dysprosium 756539.

[0033] Furthermore, the leveling agent is polyether-modified polydimethylsiloxane, specifically BYK-333.

[0034] Furthermore, the preparation method of the bismaleimide and furanyl polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol was added to a reaction vessel, heated to 80°C, and then isophorone diisocyanate and dibutyltin dilaurate were added. The reaction was carried out for 3 hours to obtain an isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 2:1. The amount of dibutyltin dilaurate was 0.1% of the mass of polycaprolactone diol. The polycaprolactone diol used was Wuhan Haishan Technology 2205, which had been pre-dehydrated under vacuum. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 60°C, add furfurylamine, and calculate the amount of furfurylamine according to the NCO:NH2 molar ratio of 1:1; stir the reaction for 2 hours to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide were mixed at a molar ratio of furan group to bismaleimide group of 1.5:1 and reacted at 70°C for 5 h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

[0035] In this embodiment, a method for preparing a UV-curable laser anti-counterfeiting color layer coating includes the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, and stir and mix them evenly at a speed of 400 r / min to obtain resin premix. (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat to 60°C, and stir at 600 r / min for 20 min; (3) Cool the mixture to room temperature, add photoinitiator and long afterglow luminescent material, stir at 1000 r / min for 30 min to obtain UV-curable laser anti-counterfeiting color layer coating.

[0036] Example 2

[0037] In this embodiment, a UV-curable laser anti-counterfeiting color layer coating comprises the following raw materials in parts by weight: 50 parts of polyurethane acrylate resin, 22 parts of epoxy acrylate resin, 6 parts of bismaleimide and furanyl polyurethane prepolymer, 2 parts of N,N'-bis(4-aminophenyl)terephthalamide, 4 parts of long afterglow luminescent material, 25 parts of reactive diluent, 2 parts of photoinitiator, and 0.5 parts of leveling agent.

[0038] Furthermore, the reactive diluent is composed of trimethylolpropane triacrylate, tripropylene glycol diacrylate and 1,6-hexanediol diacrylate in a mass ratio of 2:2:1.

[0039] Furthermore, the photoinitiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and triarylthionium hexafluoroantimonate in a mass ratio of 2:1.

[0040] Furthermore, the preparation method of the bismaleimide and furanyl polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol was added to a reaction vessel, heated to 75°C, and isophorone diisocyanate and dibutyltin dilaurate were added. The reaction was carried out for 3.5 h to obtain isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 1.9:1. The amount of dibutyltin dilaurate was 0.1% of the mass of polycaprolactone diol. Polycaprolactone diol was pre-dehydrated under vacuum. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 55°C, add furfurylamine, and calculate the amount of furfurylamine according to the NCO:NH2 molar ratio of 1:1; stir the reaction for 3 hours to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide were mixed at a molar ratio of furan group to bismaleimide group of 1.8:1 and reacted at 70°C for 5 h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

[0041] In this embodiment, a method for preparing a UV-curable laser anti-counterfeiting color layer coating includes the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, and stir and mix them evenly at a speed of 300 r / min to obtain resin premix. (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat to 55°C, and stir at 600 r / min for 30 min; (3) Cool the mixture to room temperature, add photoinitiator and long afterglow luminescent material, stir at 800 r / min for 40 min to obtain UV-curable laser anti-counterfeiting color layer coating.

[0042] The rest of the content of this embodiment is the same as that of Embodiment 1, and will not be repeated here.

[0043] Example 3

[0044] In this embodiment, a UV-curable laser anti-counterfeiting color layer coating comprises the following raw materials in parts by weight: 60 parts of polyurethane acrylate resin, 18 parts of epoxy acrylate resin, 10 parts of bismaleimide and furanyl polyurethane prepolymer, 5 parts of N,N'-bis(4-aminophenyl)terephthalamide, 8 parts of long afterglow luminescent material, 35 parts of reactive diluent, 4 parts of photoinitiator, and 1.5 parts of leveling agent.

[0045] Furthermore, the reactive diluent is composed of trimethylolpropane triacrylate, tripropylene glycol diacrylate and 1,6-hexanediol diacrylate in a mass ratio of 1:1.

[0046] Furthermore, the photoinitiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and triarylthionium hexafluoroantimonate in a mass ratio of 1:1.

[0047] Furthermore, the preparation method of the bismaleimide and furanyl polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol was added to a reaction vessel, heated to 85°C, and then isophorone diisocyanate and dibutyltin dilaurate were added. The reaction was carried out for 2.5 h to obtain an isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 2:1. The amount of dibutyltin dilaurate was 0.1% of the mass of polycaprolactone diol. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 65°C, add furfurylamine, and calculate the amount of furfurylamine according to the NCO:NH2 molar ratio of 1:1; stir the reaction for 1.5 h to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide were mixed at a molar ratio of furan group to bismaleimide group of 1:1 and reacted at 75°C for 4 h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

[0048] In this embodiment, a method for preparing a UV-curable laser anti-counterfeiting color layer coating includes the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, and stir and mix them evenly at a speed of 500 r / min to obtain resin premix. (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat to 55-65℃, and stir at 1000r / min for 20min; (3) Cool the mixture to room temperature, add photoinitiator and long afterglow luminescent material, stir at 1200 r / min for 30 min to obtain UV-curable laser anti-counterfeiting color layer coating.

[0049] The rest of the content of this embodiment is the same as that of Embodiment 1, and will not be repeated here.

[0050] Example 4

[0051] In this embodiment, a UV-curable laser anti-counterfeiting color layer coating comprises the following raw materials in parts by weight: 55 parts of polyurethane acrylate resin, 25 parts of epoxy acrylate resin, 10 parts of bismaleimide and furanyl polyurethane prepolymer, 4 parts of N,N'-bis(4-aminophenyl)terephthalamide, 5 parts of long afterglow luminescent material, 30 parts of reactive diluent, 4 parts of photoinitiator, and 2 parts of leveling agent.

[0052] Furthermore, the active diluent is trimethylolpropane triacrylate.

[0053] Furthermore, the preparation method of the bismaleimide and furanyl polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol was added to a reaction vessel, heated to 70°C, and then isophorone diisocyanate and dibutyltin dilaurate were added. The reaction was carried out for 3 hours to obtain an isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 2:1. The amount of dibutyltin dilaurate was 0.1% of the mass of polycaprolactone diol. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 60°C, add furfurylamine, and calculate the amount of furfurylamine according to the NCO:NH2 molar ratio of 1:1; stir the reaction for 2 hours to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide were mixed at a molar ratio of furan group to bismaleimide group of 1.8:1 and reacted at 70°C for 5 h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

[0054] In this embodiment, a method for preparing a UV-curable laser anti-counterfeiting color layer coating includes the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, and stir and mix them evenly at a speed of 500 r / min to obtain resin premix. (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat to 60°C, and stir at 1000 r / min for 30 min; (3) Cool the mixture to room temperature, add photoinitiator and long afterglow luminescent material, stir at 1000 r / min for 30 min to obtain UV-curable laser anti-counterfeiting color layer coating.

[0055] The rest of the content of this embodiment is the same as that of Embodiment 1, and will not be repeated here.

[0056] Comparative Example 1 The difference between this comparative example and Example 1 is that the UV-cured laser anti-counterfeiting color coating in this comparative example does not contain bismaleimide and furanyl polyurethane prepolymer, but instead uses an equal amount of polyurethane acrylate resin. The rest of this comparative example is the same as Example 1.

[0057] Comparative Example 2 The difference between this comparative example and Example 1 is that the UV-cured laser anti-counterfeiting color coating in this comparative example does not contain N,N'-bis(4-aminophenyl)terephthalamide, but is replaced with an equal amount of polyurethane acrylate resin. The rest of this comparative example is the same as Example 1.

[0058] Comparative Example 3 In this embodiment, a UV-curable laser anti-counterfeiting color layer coating comprises the following raw materials in parts by weight: 66 parts polyurethane acrylate resin, 20 parts epoxy acrylate resin, 5 parts long afterglow luminescent material, 30 parts reactive diluent, 3 parts photoinitiator, and 1 part leveling agent. The rest of the contents of this comparative example are the same as those in Example 1.

[0059] The UV-curable laser anti-counterfeiting color layer coatings prepared in Examples 1-4 and Comparative Examples 1-3 were used to prepare laser electroplated aluminum samples using the following method: (1) Apply a commercially available wax emulsion-based release coating (such as Bang Curing Chemical LX-2016) to a 12μm PET base film. After drying, the release layer thickness is about 0.5μm. (2) The UV-curable laser anti-counterfeiting color layer coating prepared by coating with a 200-mesh anilox roller has a wet film thickness of about 2μm; it is UV-cured by irradiation under a UV lamp for 20s with a power of 80W / cm. (3) A nickel plate with a holographic grating is used, the molding temperature is 90℃, the pressure is 0.3MPa, and the molding speed is 25m / min; (4) Vacuum aluminum plating is performed, with an aluminum layer thickness of 400 Å; (5) Apply commercially available thermoplastic polyolefin hot melt adhesive (such as Bang Curing Chemical BJ-666) to the aluminum layer, and dry the coating to a thickness of 1.5 μm to obtain a laser electroplated aluminum sample.

[0060] The performance of the above-mentioned laser-electroplated aluminum was tested, and the test results are shown in the table below: The test methods for each test item in the table above are as follows: (1) Hot stamping peel force: The prepared laser electroplated aluminum foil was hot stamped on white cardboard at a temperature of 150℃, a pressure of 0.3MPa, and a time of 1s. After hot stamping, a 15mm wide strip was cut and tested according to GB / T 2792-2014. The strip was peeled at 180° with a peeling speed of 300mm / min and environmental conditions of 23℃ and 50%RH.

[0061] (2) UV aging resistance: Refer to GB / T 16422.3-2022, UV-A (340nm) irradiation for 168h, and test the color difference ΔE.

[0062] (3) Resistance to damp heat: Refer to GB / T 1740-2007, temperature 60℃, humidity 95%, place for 168h, and test the color difference ΔE.

[0063] (4) Self-healing performance: Use a blade to make a scratch about 100μm wide and measure the scratch width (W1). Heat at 70℃ for 4h, take it out and cool it down, and measure the width after repair (W2) under a microscope. Repair efficiency = (W1-W2) / W1×100%. “-” in the table indicates no obvious self-healing function.

[0064] (5) Surface stickiness: Use a clean finger to lightly touch the surface of the UV-cured coating to judge whether it is sticky: no stickiness - fully cured and dry surface; slight stickiness - incomplete curing; obvious stickiness - severe oxygen inhibition.

[0065] (6) Molding clarity rating: The laser pattern of the sample after molding is observed with a 20x magnifying glass and rated from 1 to 5 according to the following standards: 5: Sharp pattern boundary, bright rainbow color, no noise; 4: Clear pattern, obvious rainbow color, slight noise; 3: Pattern is distinguishable, rainbow color is faint; 2: Pattern is blurry, rainbow color is not obvious; 1: Basically no UV curing laser effect.

[0066] (7) Afterglow time: The sample was placed under a UV lamp (365nm, 6W) for 10 minutes, then moved into a dark room. The time it took for the afterglow to completely disappear was observed and recorded by the naked eye. It was shown that the afterglow time of Example 1 and Comparative Examples 1-3 was greater than 6 hours.

[0067] The test results show that, compared with Comparative Examples 1-3, Examples 1-4 have better hot stamping adhesion, folding resistance, UV aging resistance, and damp heat resistance, and the molding clarity is higher, indicating better anti-counterfeiting effect; in addition, the surface is not sticky and has a certain degree of self-healing, making it more suitable for market demand in application.

[0068] This invention, by compounding polyurethane acrylate resin and epoxy acrylate resin and introducing raw materials such as bismaleimide and furanyl polyurethane prepolymer, N,N'-bis(4-aminophenyl)terephthalamide, long afterglow luminescent materials, reactive diluents, and photoinitiators, enables the UV-curable laser anti-counterfeiting color layer coating to possess excellent hot stamping peel strength, mechanical properties, and weather resistance, resulting in good anti-counterfeiting effects. It can be UV-cured and molded at temperatures of 80-100℃, with good hot stamping results. Furthermore, this invention, through the synergistic effect of DA dynamic covalent bonds and hydrogen bonds, endows the UV-curable laser anti-counterfeiting color layer coating with good mechanical properties and self-healing properties. The preparation method of the UV-curable laser anti-counterfeiting color layer coating is simple and easy to control, with a stable process, which is conducive to industrial production.

[0069] The specific embodiments described above are further illustrations of the technical solution and beneficial effects of the present invention, and are not intended to limit the implementation methods. For those skilled in the art, any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A UV-cured laser anti-counterfeiting color layer coating, characterized in that: The raw materials include the following parts by weight: 50-60 parts of polyurethane acrylate resin, 15-25 parts of epoxy acrylate resin, 5-10 parts of bismaleimide and furanyl polyurethane prepolymer, 2-5 parts of N,N'-bis(4-aminophenyl)terephthalamide, 3-8 parts of long afterglow luminescent material, 25-35 parts of reactive diluent, 2-5 parts of photoinitiator, and 0.5-2 parts of leveling agent.

2. The UV-cured laser anti-counterfeiting color layer coating according to claim 1, characterized in that: The reactive diluent is at least one of trimethylolpropane triacrylate, tripropylene glycol diacrylate, and 1,6-hexanediol diacrylate.

3. The UV-curable laser anti-counterfeiting color coating according to claim 1, characterized in that: The photoinitiator is an acylphosphine oxide photoinitiator or a thionium salt cationic photoinitiator.

4. The UV-curable laser anti-counterfeiting color coating according to claim 3, characterized in that: The acylphosphine oxide photoinitiator is at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide; the thionium salt cationic photoinitiator is at least one of triarylthionium salt and diaryliodoonium salt.

5. The UV-curable laser anti-counterfeiting color coating according to claim 1, characterized in that: The long afterglow luminescent material is europium aluminate dysprosium.

6. The UV-curable laser anti-counterfeiting color coating according to claim 1, characterized in that: The leveling agent is polyether-modified polydimethylsiloxane.

7. The UV-curable laser anti-counterfeiting color coating according to claim 1, characterized in that: The preparation method of the bismaleimide-furan-based polyurethane prepolymer includes the following steps: (A1) Under nitrogen protection, polycaprolactone diol was added to the reaction vessel, the temperature was raised to 75-85℃, isophorone diisocyanate and catalyst were added, and the reaction was carried out for 2-4 hours to obtain isocyanate-terminated polyurethane prepolymer with an NCO / OH molar ratio of 1.8-2.2:

1. (A2) Cool the isocyanate-terminated polyurethane prepolymer to 55-65℃, add furfurylamine, and stir for 1-3 hours to obtain furan-terminated polyurethane. (A3) Furan-terminated polyurethane and N,N'-(4,4'-methylenediphenyl)bismaleimide are mixed at a molar ratio of furan group to bismaleimide group of 1:0.5-1 and reacted at 65-75℃ for 4-7h to obtain a bismaleimide and furan-terminated polyurethane prepolymer.

8. The UV-curable laser anti-counterfeiting color coating according to claim 7, characterized in that: In step (A1), the catalyst is at least one of dibutyltin dilaurate and an organobismuth catalyst.

9. A method for preparing a UV-curable laser anti-counterfeiting color layer coating as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Weigh polyurethane acrylate resin, epoxy acrylate resin, bismaleimide and furanyl polyurethane prepolymer and reactive diluent according to the weight parts, add them to the reaction vessel, stir and mix evenly to obtain resin premix; (2) Add N,N'-bis(4-aminophenyl)terephthalamide and leveling agent to the resin premix, heat and stir until uniform; (3) Cool the mixture to room temperature, add photoinitiator and long afterglow luminescent material, stir evenly to obtain UV-cured laser anti-counterfeiting color layer coating.

10. The method for preparing the UV-curable laser anti-counterfeiting color layer coating according to claim 9, characterized in that: In step (2), N,N'-bis(4-aminophenyl)terephthalamide and leveling agent are added to the resin premix, the temperature is raised to 55-65℃, and the mixture is stirred until homogeneous.

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